U.S. patent application number 11/720369 was filed with the patent office on 2008-10-16 for sterilising filter arrangement apparatus & method.
This patent application is currently assigned to ALPHA TECHNOLOGIES CORPORATION LTD. Invention is credited to Richard Rubin.
Application Number | 20080253754 11/720369 |
Document ID | / |
Family ID | 36564672 |
Filed Date | 2008-10-16 |
United States Patent
Application |
20080253754 |
Kind Code |
A1 |
Rubin; Richard |
October 16, 2008 |
Sterilising Filter Arrangement Apparatus & Method
Abstract
A sterilizing hand-drying apparatus is used to produce a stream
of sterilized, heated air for drying hands. The apparatus is
provided with an electric control circuit that supplies electrical
power to the apparatus. The electric control circuit has a cut-off
mechanism that disables the supply of electrical power when the
housing is opened. This minimizes the risk of the user being
electrocuted when opening the housing.
Inventors: |
Rubin; Richard; (Victoria,
AU) |
Correspondence
Address: |
STITES & HARBISON PLLC
1199 NORTH FAIRFAX STREET, SUITE 900
ALEXANDRIA
VA
22314
US
|
Assignee: |
ALPHA TECHNOLOGIES CORPORATION
LTD
Melbourne
AU
|
Family ID: |
36564672 |
Appl. No.: |
11/720369 |
Filed: |
November 30, 2005 |
PCT Filed: |
November 30, 2005 |
PCT NO: |
PCT/AU05/01803 |
371 Date: |
June 10, 2008 |
Current U.S.
Class: |
392/381 |
Current CPC
Class: |
B01D 46/10 20130101;
A47L 7/04 20130101; A47L 9/122 20130101; B01D 46/0005 20130101;
B01D 2257/91 20130101; A61L 9/04 20130101; A61L 9/16 20130101; A47K
10/48 20130101; B01D 46/0028 20130101; B01D 2267/40 20130101; A45D
20/12 20130101; D06F 58/20 20130101 |
Class at
Publication: |
392/381 |
International
Class: |
A47K 10/48 20060101
A47K010/48 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 30, 2004 |
AU |
2004233510 |
Sep 20, 2005 |
AU |
2005905191 |
Claims
1-122. (canceled)
123. A sterilizing hand-drying apparatus adapted to produce a
stream of substantially sterilized, heated air for drying hands,
the apparatus including: a housing; heating-means positioned in the
housing for heating of air useable for drying hands; inlet-means
through which the air, in use, enters the housing and travels to
reach the heating-means; outlet-means through which the air, in
use, after being heated by the heating-means, is emitted as heated
air useable for drying hands; and airflow-generation-means adapted
to move the air swiftly as an airflow from the inlet-means via the
heating-means to the outlet-means; wherein the apparatus is
provided with an electric control circuit that supplies electrical
power to the apparatus, and wherein the electric control circuit is
provided with a cut-off mechanism that disables the supply of
electrical power when the housing is opened so as to minimize risk
of the user being electrocuted when opening the housing.
124. Apparatus of claim 123 wherein the cut-off mechanism includes
a two-state switch which enables the supply of electrical power
only when in the first state, and wherein an actuator is provided
within the housing that maintains the switch in the first state
when the housing is closed, and which activates the switch into the
second state when the housing is opened to thereby disable the
supply of electrical power to the apparatus when the housing is
opened.
125. Apparatus of claim 123 wherein the cut-off mechanism includes
a resiliently-mounted switch which enables the supply of electrical
power only when activated, and wherein a
cut-off-mechanism-activator is provided within the housing and
arranged so as to activate the switch when the housing is closed,
and to deactivate the switch when the housing is opened thereby to
disable the supply of electrical power to the apparatus when the
housing is opened.
126. Apparatus of claim 125 wherein the resiliently-mounted switch
is mounted on a base-mounting to which a hood of the housing is
removably attachable, and the cut-off-mechanism-activator is
mounted on an interior surface of the hood.
127. Apparatus of claims 125 wherein the
cut-off-mechanism-activator is mounted on a base-mounting to which
a hood of the housing is removably attachable, and the
resiliently-mounted switch is mounted on an interior surface of the
hood.
128. Apparatus of claims 126 wherein the
cut-off-mechanism-activator is in the form of a depressor that
activates the cut-off mechanism when in contact therewith.
129. Apparatus of claim 127 wherein the cut-off-mechanism-activator
is in the form of a depressor that activates the cut-off mechanism
when in contact therewith.
130. Apparatus of claim 126 wherein the base-mounting is adapted to
be fastened to an upright mounting surface, such that the
hand-drying apparatus is able to be installed onto the upright
mounting surface by attaching the housing to the base-mounting.
131. Apparatus of claim 127 wherein the base-mounting is adapted to
be fastened to an upright mounting surface, such that the
hand-drying apparatus is able to be installed onto the upright
mounting surface by attaching the housing to the base-mounting.
132. A baseplate to which a hood of a housing of a sterilising
hand-drying apparatus is adapted to be removably attached, wherein
the hand-drying apparatus is provided with an electric control
circuit that supplies electrical power to the apparatus, and
wherein the baseplate is provided with a cut-off mechanism that
disables the supply of electrical power to the electric control
circuit when, in use with the hood attached to the baseplate, the
housing is opened so as to minimise risk of the user being
electrocuted when opening the housing.
133. A baseplate to which a hood of a housing of a sterilising
hand-drying apparatus is adapted to be removably attached, wherein
the hand-drying apparatus is provided with an electric control
circuit that supplies electrical power to the apparatus, and
wherein the baseplate is provided with a cut-off mechanism that
disables the supply of electrical power to the electric control
circuit when, in use with the hood attached to the baseplate, the
housing is opened so as to minimise risk of the user being
electrocuted when opening the housing, and wherein the sterilising
hand-drying apparatus includes: a housing; heating-means positioned
in the housing for heating of air useable for drying hands;
inlet-means through which the air, in use, enters the housing and
travels to reach the heating-means; outlet-means through which the
air, in use, after being heated by the heating-means, is emitted as
heated air useable for drying hands; and airflow-generation-means
adapted to move the air swiftly as an airflow from the inlet-means
via the heating-means to the outlet-means.
134. A sterilising hand-drying apparatus adapted to produce a
stream of substantially sterilised, heated air for drying hands,
the apparatus including: a housing; heating-means positioned in the
housing for heating of air useable for drying hands; inlet-means
through which the air, in use, enters the housing and travels to
reach the heating-means; outlet-means through which the air, in
use, after being heated by the heating-means, is emitted as heated
air useable for drying hands; airflow-generation-means adapted to
move the air swiftly as an airflow from the inlet-means via the
heating-means to the outlet-means; and filter material adapted to
filter the airflow; wherein the apparatus includes a
filter-replacement mechanism that is able to automatically replace
the filter material in use with replacement filter material.
135. Apparatus of claim 134 wherein the filter-replacement
mechanism replaces the filter material in use with replacement
filter material periodically after a period of time.
136. Apparatus of claim 134 wherein the filter-replacement
mechanism replaces the filter material in use with replacement
filter material progressively in a continuous or intermittent
manner.
137. Apparatus of claim 136 wherein the filter material is in the
form of a sheet-like strip.
138. Apparatus of claim 137 wherein the filter material is conveyed
by a motorized reel-mechanism.
139. Apparatus of claim 134 wherein the filter material includes
bacteria-entrapment-filter-means through which, in use, the airflow
passes, and wherein the bacteria-entrapment-filter-means, in use,
is adapted to trap and retain therein a substantial portion of
bacteria in the airflow, such that the airflow leaving the
bacteria-entrapment-filter-means is more sterile than when entering
the bacteria-entrapment-filter-means.
140. An auto filter-replacement mechanism to change filter material
of a sterilizing hand-drying apparatus, said hand drying apparatus
including: a housing; heating-means positioned in the housing for
heating of air useable for drying hands; inlet-means through which
the air, in use, enters the housing and travels to reach the
heating-means; outlet-means through which the air, in use, after
being heated by the heating-means, is emitted as heated air useable
for drying hands; airflow-generation-means adapted to move the air
swiftly as an airflow from the inlet-means via the heating-means to
the outlet-means; and filter material adapted to filter the
airflow, said auto filter-replacement mechanism providing automatic
replacement of the filter material in use with replacement filter
material.
Description
FIELD OF INVENTION
[0001] The present invention relates to an improvement in
components used in indoor apparatus which have an internal airflow
that is expelled from the apparatus into an indoor human-activity
environment.
[0002] One aspect of the invention relates particularly to an
improvement in a filter arrangement used to sterilise the airflow
that emanates from such indoor apparatus.
[0003] Other preferred aspects of the invention relate to features
that contribute to the goal of achieving 100% bacteria removal from
the airflow.
[0004] Other aspects of the present invention also relate to
improved devices that give off an airflow, particularly, but not
exclusively, to hand dryers, hair dryers, vacuum cleaners, air
fans, air conditioners, refrigerators, clothing tumble dryers.
BACKGROUND OF THE INVENTION
Spread Of Bacteria By Airflow Apparatus
[0005] It is known that indoor apparatus, which draw in air and
then expel that air as an airflow into the indoor human-activity
environment, are a vehicle for spreading germs, bacteria and
viruses. As a result, the people in this environment can more
readily come into contact with the bacteria that are spread around
by the expelled air from the apparatus.
[0006] For example, the prior art includes a number of hand drying
apparatus that emit a stream of warm airflow to dry the hands. It
was assumed that the use of such hand drying apparatus is hygienic.
Contrary to expectations, however, it has been found that these
prior art hand drying apparatus are actually a means of spreading
the germs.
[0007] The reason is that the warm airflow from these prior art
hand drying apparatus is, itself, laden with airborne bacteria.
This is because the hand dryers draw in air from the bacteria-laden
atmosphere of the toilet, and expel the warm, germ-infested airflow
onto the wet hands of the user.
[0008] Moreover, many people do not leave their hands in the warm
airstream for long enough to completely dry their hands. As a
result, the warm moist environment on the user's hands is ideal for
the bacteria, that has been blown onto the hands by the dryer, to
multiply rapidly.
[0009] Many of the micro-organisms in the airflow are not killed by
the heating element of hand dryers. Moreover, the warm air from a
hand dryer is an ideal environment for bacteria to multiply.
Consequently, these live bacteria are directed onto the user's
hands. Indeed, it is found that such hot air blowers in the prior
art may actually increase bacteria levels by up to 500%.
The Problem of Less-Than-100% Bacteria Removal
[0010] Even though such prior art hand drying apparatus have found
widespread acceptance in public facilities, such as public toilets,
there is resistance to using these apparatus in the certain fields,
particularly the medical field such as in hospitals and medical
clinics, and also in childcare centres and in the food
industry.
[0011] For instance, when a surgeon, prior to performing surgery,
washes his hands with anti-bacteria liquid or soap, it would be
futile if the surgeon's hands were to be re-infected with bacteria,
if the surgeon were to dry his wet hands in the warm airflow of a
prior art hand drying apparatus.
[0012] Also, in the new Millennium, virologists and public health
officials predict a future worldwide pandemic of deadly flu and
other viruses in terms of when it will happen, rather than if such
a pandemic might occur. When such a global pandemic occurs, it can
also be predicted that there will be a need for 100% bacteria
removal in indoor apparatus that emit airflows. If not, such
apparatus, particularly in public places, even if capable of
removing say 90% of bacteria, would still become vehicles for
spreading deadly virus in the pandemic. In other words, during a
pandemic, 100% bacteria removal would become critically
important.
[0013] The prior art contains air-flow apparatus that are intended
to kill bacteria and/or remove the bacteria from the airflow of the
apparatus, however, in actual practice, such known products do not
come close to removing 100% of the bacteria from the airflow in the
apparatus, particularly through long-term use.
[0014] Even though such prior art apparatus may kill or remove part
of the bacteria in the airflow, the ultimate goal of 100% bacteria
removal has remained elusive.
[0015] Hence, at the outset of this specification, a distinction is
made between a prior art apparatus that make an assertion of
killing or removing bacteria, but, in actual performance, only
achieves, say, 80% and even 90 or 95% removal of the bacteria from
the airflow, in contrast to the present goal of removing 100% of
bacteria from the airflow.
[0016] An invention that aims for 100% bacteria removal faces a
different set of obstacles which are unlikely to be addressed by a
prior art apparatus that does not necessarily aim for, nor achieve,
100% bacteria removal.
Prior Art
[0017] Attempts have been made in the prior art to enable airflow
apparatus to produce a sterilised stream of warm air. A major area
of development in this field has focused on the use of ultraviolet
(UV) radiation in an attempt to kill the bacteria in the airflow.
Contrary to expectations, however, it has been ascertained that UV
radiation performs poorly in the task of killing the bacteria in
the airstream.
[0018] Firstly, it must be remembered that, even if the UV
radiation were to kill a large portion of the bacteria, the fact is
that the remaining bacteria in the airflow can still reach the
user's hands, and begin multiplying in a matter of minutes.
[0019] Secondly, some microbiologist are of the view that UV
radiation does not actually kill the bacteria, but merely
sterilizes the bacteria, in that sense that UV merely stops the
bacteria from breeding or multiplying. If this is true, then it
would mean that the warm airflow, emanating from UV-equipped
hand-dryers, would still contain an unhygienic content of live
bacteria.
[0020] This ultimate level of sanitisation, namely 100% bacteria
removal, would be particularly important for surgical or medical
applications. In this regard, laboratory tests conducted for the
inventor show that some ultraviolet-equipped hand drying machines,
currently on the market, do not kill 100% of the bacteria in the
emitted airflow.
[0021] Thus, prior art hand drying apparatus are often not favoured
for use in medical applications where the strictest standard of
sterilisation of hands is critically important, particularly in the
area of surgery, and in the medical treatment of open wounds.
[0022] Another problem is that, over a period of weeks, months or
even years, germs can collect inside the apparatus. As airflow is
drawn inside the apparatus, through continued use, amounts of
bacteria are constantly drawn into the machine. In other words, all
the inner surfaces of the machine, which come in contact with the
airflow, are constantly exposed to bacteria. Over time, the insides
of the machine can become a source of bacteria. When the machine is
turned off, or when it is not generating an airflow, the bacteria
inside can continue to grow and multiply. When a prior art
apparatus is incapable of 100% bacteria removal, then those
remanent of the bacteria remains in the apparatus, and then
internal surfaces of the apparatus can, over time, become a source
of bacteria.
[0023] Other types of apparatus are also used to spread bacteria
indoors by their emitted airflows. For example, air-conditioners
draw in air, either from outdoors or from the indoor environment,
and then expel the airflow indoors. Thus, if there is not a 100%
killing or removal of the bacteria in the airflow expelled from the
air conditioner, there is likely to be, over a period of time, a
gradual net build-up of bacteria in the air of the indoor
environment.
[0024] As another example, a vacuum cleaner draws in bacteria as it
sucks up particulate from the floor or surfaces. While the
filtration of the vacuum cleaner system can filter out particulate
from the airflow, there remains in the airflow minute particles of
bacteria. These are spread into the indoor environment by the
airflow emanating from the vacuum cleaner.
[0025] The same phenomenon of spreading bacteria can be seen in
other airflow apparatus that draw in and expel an airflow. These
include, for example, hair dryers, fans and clothes dryers. In the
case of clothes dryers, bacteria-laden air is drawn in from the
indoor environment, and directed onto the clothes.
[0026] Even a refrigerator draws in air, and expels the
bacteria-laden air into the cooling chamber of the refrigerator,
exposing foods to the bacteria.
[0027] An object of some of the several aspects of the present
invention is to provide one or more features that, individually or
in combination, enable an apparatus, that emits an airflow into a
human activity environment, to achieve 100% bacteria reduction in
the airflow leaving the filtration arrangement.
[0028] Another object of the present invention is to overcome or
ameliorate one or more problems in the prior art, or to provide an
improved alternative over the prior art.
[0029] Discussion of prior art in this specification should not be
taken as an admission or a commentary on the state of common
general knowledge of the skilled addressee in this field.
SUMMARY OF INVENTION
[0030] The present specification contains several aspects of the
present invention.
[0031] According to a first aspect of the present invention, there
is provided a sterilising hand-drying apparatus adapted to produce
a stream of substantially sterilised, heated air for drying hands,
the apparatus including:
[0032] a housing;
[0033] heating-means positioned in the housing for heating of air
useable for drying hands;
[0034] inlet-means through which the air, in use, enters the
housing and travels to reach the heating-means;
[0035] outlet-means through which the air, in use, after being
heated by the heating-means, is emitted as heated air useable for
drying hands; and
[0036] airflow-generation-means adapted to move the air swiftly as
an airflow from the inlet-means via the heating-means to the
outlet-means;
[0037] wherein the apparatus is provided with
bacteria-entrapment-filter-means through which, in use, the airflow
passes, and
[0038] wherein the bacteria-entrapment-filter-means, in use, is
adapted to trap and retain therein a substantial portion of
bacteria in the airflow, such that the airflow leaving the
bacteria-entrapment-filter-means is more sterile than when entering
the bacteria-entrapment-filter-means,
[0039] the entrapment filter-means being in the form of a fibrous
matrix that has on its fibres a toxic bacteria-killing substance
which is able to kill any bacteria that impinges on the
bacteria-killing substance on the fibres.
[0040] Preferably, the bacteria-killing substance is a
liquid-applied substance which, when on the fibre, presents a
sticky coating on the fibre which captures bacteria that impinges
on the bacteria-killing substance found on the fibres.
[0041] In the exemplary embodiment, the airflow leaving the
bacteria-entrapment-filter-means has numerically fewer bacteria
than the airflow entering the bacteria-entrapment-filter-means.
[0042] Preferably, the airflow leaving the
bacteria-entrapment-filter-means is fully or at least substantially
bacteria-free.
[0043] Preferably, the airflow leaving the
bacteria-entrapment-filter-means is 100% free of bacteria
particles.
[0044] Preferably, the bacteria-entrapment-filter-means intercepts
the airflow before the airflow reaches the heating-means.
[0045] Preferably, the inlet-means includes at least one main
entrance through which all the airflow that is emitted from the
hand-drying apparatus has to pass initially through this main
entrance
[0046] Preferably, the at least one main entrances is located
totally inside the housing.
[0047] Preferably, the at least one main entrance is located in an
entrance into the airflow-generation-means such that all air
entering the airflow-generation-means passes through this at least
one main entrance.
[0048] Preferably, the airflow-generation-means is contained in a
casing and wherein said at least one main entrance is located on
the casing.
[0049] Alternatively, the at least one main entrance may be located
on the housing of the apparatus, provided that all other entrances
into the housing, apart from said at least one main entrance, are
sealed so that, in operational use, air can only enter the housing
through said at least one main entrance.
[0050] Preferably, the inlet-means includes one or more secondary
entrances arranged in series with the main entrance through which
the airflow passes sequentially one after another.
[0051] The main entrance may be separated from its next nearest
entrance in the series by a substantial space that contains
sufficient air to satisfy the air intake requirements of the
airflow-generation-means in terms of volume of air per unit
time.
[0052] At least one of the secondary entrances may be located on an
external surface of the housing, and accessible by the user from
outside of the housing.
[0053] Preferably, each of said secondary entrances is provided
with said bacteria-entrapment-filter-means.
[0054] Preferably, the main entrance is provided with said
bacteria-entrapment-filter-means.
[0055] Preferably, said bacteria-entrapment-filter-means includes a
fibrous, dense filter material that is sufficiently dense to
intercept and entrap a substantial portion of bacteria particles in
the airflow.
[0056] Preferably, the filter material is a non-woven fibre.
[0057] Preferably, the filter material has average gaps or pores
between the fibres selected to be around 150 microns.
[0058] Preferably, the filter material has an air permeability of
around 234.7 cm3/cm2/sec.
[0059] The bacteria-entrapment-filter-means may include a
filter-replacement mechanism that is able to automatically replace
the filter material in use with replacement filter material.
[0060] Preferably, filter-replacement mechanism replaces the filter
material in use with replacement filter material periodically after
a period of time. Preferably, the filter-replacement mechanism
replaces the filter material in use with replacement filter
material progressively in a continuous or intermittent manner.
Preferably, the filter material is in the form of a sheet-like
strip. Preferably, the filter material is conveyed by a motorised
reel-mechanism.
[0061] Preferably, the apparatus is provided with an electric
control circuit that supplies electrical power to the apparatus,
and wherein the electric control circuit is provided with a cut-off
mechanism that disables the supply of electrical power when the
housing is opened so as to minimise risk of the user being
electrocuted when opening the housing.
[0062] Preferably, the cut-off mechanism includes a two-state
switch which enables the supply of electrical power only when in
the first state, and wherein an actuator is provided within the
housing that maintains the switch in the first state when the
housing is closed, and which activates the switch into the second
state when the housing is opened to thereby disable the supply of
electrical power to the apparatus when the housing is opened.
[0063] Preferably, the cut-off mechanism includes a
resiliently-mounted switch which enables the supply of electrical
power only when depressed, and wherein a
cut-off-mechanism-activator is provided within the housing and
arranged so as to depresses the switch when the housing is closed,
and to lift off the switch when the housing is opened thereby to
disable the supply of electrical power to the apparatus when the
housing is opened.
[0064] Preferably, the resiliently-mounted switch is mounted on a
base-mounting to which a hood of the housing is removably
attachable, and the cut-off-mechanism-activator is mounted on an
interior surface of the hood.
[0065] Preferably, the cut-off-mechanism-activator is mounted on a
base-mounting to which a hood of the housing is removably
attachable, and the resiliently-mounted switch is mounted on an
interior surface of the hood.
[0066] The cut-off-mechanism-activator may be in the form of a
depressor that activates the cut-off mechanism when in contact
therewith.
[0067] The base-mounting may be adapted to be fastened to an
upright mounting surface, such that the hand-drying apparatus is
able to be installed onto the upright mounting surface by attaching
the housing to the base-mounting.
[0068] The hand-drying apparatus may be provided with a
timer-control-circuit to regularly auto-activate the
airflow-generation-means for a predetermined period of time so that
the hand-drying apparatus effectively sterilises part of the
ambient atmosphere surrounding the hand-drying apparatus.
[0069] The timer-control-circuit may auto-activate the apparatus
without concurrently activating the heating-means.
[0070] Alternatively, the timer-control-circuit may auto-activate
the apparatus while concurrently activating the heating-means.
[0071] The timer-control-circuit may be provided with
light-sensor-means and only auto-activates the apparatus only the
light-sensor indicates that there is ambient light.
[0072] Preferably, the apparatus is provided with hand-sensor-means
which detects the presence of hands in the vicinity of the
outlet-means and is adapted to activate the
airflow-generation-means and the heating-means when hands are so
detected, and wherein the timer-control-circuit only auto-activates
the apparatus when the hand-sensor-means detects that there is no
presence of hands in the vicinity of the outlet-means.
[0073] Preferably, the bacteria-entrapment-filter-means includes an
airborne-bacteria filter arrangement described below.
[0074] According to a second aspect of the present invention, there
is provided a method of producing a stream of substantially
sterilised, heated air from a sterilising hand-drying apparatus for
drying hands, the method including:
[0075] using airflow-generation-means to move air swiftly as an
airflow;
[0076] heating the air with heating-means so that the airflow is
useable for drying hands;
[0077] providing the hand-drying apparatus with
bacteria-entrapment-filter-means through which, in use, the airflow
passes; and
[0078] wherein the bacteria-entrapment-filter-means, in use, is
adapted to trap and retain therein a substantial portion of
bacteria in the airflow, such that the airflow leaving the
bacteria-entrapment-filter-means is more sterile than when entering
the bacteria-entrapment-filter-means,
[0079] the entrapment filter-means being in the form of a fibrous
matrix that has on its fibres a toxic bacteria-killing substance
which is able to kill any bacteria that impinges on the
bacteria-killing substance on the fibres.
[0080] According to a third aspect of the present invention, there
is provided a sterilising hand-drying apparatus adapted to produce
a stream of substantially sterilised, heated air for drying hands,
the apparatus including:
[0081] a housing;
[0082] heating-means positioned in the housing for heating of air
useable for drying hands;
[0083] inlet-means through which the air, in use, enters the
housing and travels to reach the heating-means;
[0084] outlet-means through which the air, in use, after being
heated by the heating-means, is emitted as heated air useable for
drying hands; and
[0085] airflow-generation-means adapted to move the air swiftly as
an airflow from the inlet-means via the heating-means to the
outlet-means;
[0086] wherein the apparatus is provided with an electric control
circuit that supplies electrical power to the apparatus,
[0087] and wherein the electric control circuit is provided with a
cut-off mechanism that disables the supply of electrical power when
the housing is opened so as to minimise risk of the user being
electrocuted when opening the housing.
[0088] Preferably, the cut-off mechanism includes a two-state
switch which enables the supply of electrical power only when in
the first state, and wherein an actuator is provided within the
housing that maintains the switch in the first state when the
housing is closed, and which activates the switch into the second
state when the housing is opened to thereby disable the supply of
electrical power to the apparatus when the housing is opened.
[0089] Preferably, the cut-off mechanism includes a
resiliently-mounted switch which enables the supply of electrical
power only when activated, and wherein a
cut-off-mechanism-activator is provided within the housing and
arranged so as to activate the switch when the housing is closed,
and to deactivate the switch when the housing is opened thereby to
disable the supply of electrical power to the apparatus when the
housing is opened.
[0090] The resiliently-mounted switch may be mounted on a
base-mounting to which a hood of the housing is removably
attachable, and the cut-off-mechanism-activator is mounted on an
interior surface of the hood.
[0091] The cut-off-mechanism-activator may be mounted on a
base-mounting to which a hood of the housing is removably
attachable, and the resiliently-mounted switch is mounted on an
interior surface of the hood.
[0092] The cut-off-mechanism-activator may be in the form of a
depressor that activates the cut-off mechanism when in contact
therewith.
[0093] The base-mounting may be adapted to be fastened to an
upright mounting surface, such that the hand-drying apparatus is
able to be installed onto the upright mounting surface by attaching
the housing to the base-mounting.
[0094] According to a fourth aspect of the present invention, there
is provided baseplate to which a hood of a housing of a sterilising
hand-drying apparatus is adapted to be removably attached,
[0095] wherein the hand-drying apparatus is provided with an
electric control circuit that supplies electrical power to the
apparatus,
[0096] and wherein the baseplate is provided with a cut-off
mechanism that disables the supply of electrical power to the
electric control circuit when, in use with the hood attached to the
baseplate, the housing is opened so as to minimise risk of the user
being electrocuted when opening the housing.
[0097] According to a fifth aspect of the present invention, there
is provided a sterilising hand-drying apparatus adapted to produce
a stream of substantially sterilised, heated air for drying hands,
the apparatus including:
[0098] a housing;
[0099] heating-means positioned in the housing for heating of air
useable for drying hands;
[0100] inlet-means through which the air, in use, enters the
housing and travels to reach the heating-means;
[0101] outlet-means through which the air, in use, after being
heated by the heating-means, is emitted as heated air useable for
drying hands; and
[0102] airflow-generation-means adapted to move the air swiftly as
an airflow from the inlet-means via the heating-means to the
outlet-means;
[0103] wherein the hand-drying apparatus is provided with a
timer-control-circuit to regularly auto-activate the
airflow-generation-means for a predetermined period of time.
[0104] The timer-control-circuit may auto-activate the apparatus
without concurrently activating the heating-means.
[0105] Alternatively, the timer-control-circuit may auto-activate
the apparatus while concurrently activating the heating-means.
[0106] The timer-control-circuit may be provided with
light-sensor-means and only auto-activates the apparatus only the
light-sensor indicates that there is ambient light.
[0107] The apparatus may be provided with hand-sensor-means which
detects the presence of hands in the vicinity of the outlet-means
and is adapted to activate the airflow-generation-means and the
heating-means when hands are so detected, and wherein the
timer-control-circuit only auto-activates the apparatus when the
hand-sensor-means detects that there is no presence of hands in the
vicinity of the outlet-means.
[0108] The apparatus may be provided with a fragrance-material that
is a source of fragrance so that the fragrance infuses into the
airflow.
[0109] According to a sixth aspect of the present invention, there
is provided a timing circuit component adapted to regularly
auto-activate airflow-generation-means in a sterilising hand-drying
apparatus for a predetermined period of time,
[0110] the sterilising hand-drying apparatus adapted to produce a
stream of substantially sterilised, heated air for drying hands,
the apparatus including:
[0111] a housing;
[0112] heating-means positioned in the housing for heating of air
useable for drying hands;
[0113] inlet-means through which the air, in use, enters the
housing and travels to reach the heating-means;
[0114] outlet-means through which the air, in use, after being
heated by the heating-means, is emitted as heated air useable for
drying hands; and
[0115] said airflow-generation-means adapted to move the air
swiftly as an airflow from the inlet-means via the heating-means to
the outlet-means;
[0116] wherein the timer-control-circuit is adapted to regularly
auto-activate the airflow-generation-means for a predetermined
period of time.
[0117] According to a seventh aspect of the present invention,
there is provided a method of sterilising ambient atmosphere around
a sterilising hand-drying apparatus that is adapted to produce a
stream of substantially sterilised, heated air for drying hands,
the method including:
[0118] providing the hand-drying apparatus with a
timer-control-circuit that is adapted to regularly auto-activate
the airflow-generation-means for a predetermined period of time;
and
[0119] using the timer-control-circuit to auto-activate the
sterilising hand-drying apparatus periodically for a predetermined
period of time,
[0120] wherein the hand-drying apparatus includes:
[0121] a housing;
[0122] heating-means positioned in the housing for heating of air
useable for drying hands;
[0123] inlet-means through which the air, in use, enters the
housing and travels to reach the heating-means;
[0124] outlet-means through which the air, in use, after being
heated by the heating-means, is emitted as heated air useable for
drying hands; and
[0125] airflow-generation-means adapted to move the air swiftly as
an airflow from the inlet-means via the heating-means to the
outlet-means.
[0126] According to a eighth aspect of the present invention, there
is provided a method of fragrancing ambient atmosphere around a
hand-drying apparatus that is adapted to produce an airflow of
heated air for drying hands, the method including:
[0127] providing the hand-drying apparatus with a
timer-control-circuit that is adapted to regularly auto-activate
the airflow-generation-means for a predetermined period of
time;
[0128] providing the apparatus with a fragrance-material that is a
source of fragrance so that the fragrance infuses into the airflow;
and
[0129] using the timer-control-circuit to auto-activate the
hand-drying apparatus periodically for a predetermined period of
time, which effectively causes the fragrance in the airflow to
fragrance the ambient atmosphere around the hand-drying
apparatus;
[0130] wherein the hand-drying apparatus includes:
[0131] a housing;
[0132] heating-means positioned in the housing for heating of air
useable for drying hands;
[0133] inlet-means through which the air, in use, enters the
housing and travels to reach the heating-means;
[0134] outlet-means through which the air, in use, after being
heated by the heating-means, is emitted as heated air useable for
drying hands; and
[0135] airflow-generation-means adapted to move the air swiftly as
an airflow from the inlet-means via the heating-means to the
outlet-means.
[0136] According to a ninth aspect of the present invention, there
is provided a sterilising hand-drying apparatus adapted to produce
a stream of substantially sterilised, heated air for drying hands,
the apparatus including:
[0137] a housing;
[0138] heating-means positioned in the housing for heating of air
useable for drying hands;
[0139] inlet-means through which the air, in use, enters the
housing and travels to reach the heating-means; outlet-means
through which the air, in use, after being heated by the
heating-means, is emitted as heated air useable for drying
hands;
[0140] airflow-generation-means adapted to move the air swiftly as
an airflow from the inlet-means via the heating-means to the
outlet-means; and
[0141] filter material adapted to filter the airflow;
[0142] wherein the apparatus includes a filter-replacement
mechanism that is able to automatically replace the filter material
in use with replacement filter material.
[0143] According to a tenth aspect of the present invention, there
is provided a sterilising hand-drying apparatus adapted to produce
a stream of substantially sterilised, heated air for drying hands,
the apparatus including:
[0144] a housing;
[0145] heating-means positioned in the housing for heating of air
useable for drying hands;
[0146] inlet-means through which the air, in use, enters the
housing and travels to reach the heating-means;
[0147] outlet-means through which the air, in use, after being
heated by the heating-means, is emitted as heated air useable for
drying hands; and
[0148] airflow-generation-means adapted to move the air swiftly as
an airflow from the inlet-means via the heating-means to the
outlet-means;
[0149] wherein the inlet-means includes at least one main entrance
through which all airflow in the apparatus must pass through said
at least one main entrance, and
[0150] wherein the at least one main entrance is located in an
entrance into the airflow-generation-means such that all air
entering the airflow-generation-means passes through this at least
one main entrance which is filtered.
[0151] According to a eleventh aspect of the present invention,
there is provided an airborne-bacteria filter arrangement adapted
to be used with an apparatus that draws in and expels an airflow
into a human-activity environment, the filter arrangement including
the following through which the airflow passes in sequence:
[0152] i) entrapment filter-means in the form of a fibrous matrix
that has on its fibres a toxic bacteria-killing substance which is
able to kill any bacteria that impinges on the bacteria-killing
substance on the fibres.
[0153] Preferably, after the entrapment filter-means, the airflow
passes through:
[0154] ii) carbon filter-means that intercepts and removes from the
airflow any of the toxic bacteria-killing substance that originates
from the entrapment filter means so that the airflow leaving the
filter arrangement into the human-activity area is substantially
free both of bacteria and of traces of the bacteria-killing
substance.
[0155] Preferably, the airborne-bacteria filter arrangement is
located fully inside the apparatus interior.
[0156] Preferably, the filter arrangement is provided with
filter-barrier-means which, in use, houses the entrapment filter
means and the charcoal-filter-means so as to provide a
bacteria-impermeable barrier therefor.
[0157] Preferably, the bacteria-impermeable barrier of the
filter-barrier-means separates the entrapment filter means and the
charcoal-filter-means from the interior of the apparatus such that,
in use with the airflow, bacteria or other contaminants inside the
apparatus can only enter the filter arrangement via the entrapment
filter means and not through other parts of the filter
arrangement.
[0158] Preferably, the bacteria-impermeable barrier includes
components that are adapted to fit together such that, when fitted
together, bacteria cannot enter the interior of the filter
arrangement through points of abutment of the components.
[0159] Preferably, the bacteria-impermeable barrier of the
filter-barrier-means also prevents any live bacteria inside the
filter arrangement from escaping therefrom back into the apparatus
interior.
[0160] Preferably, the entrapment filter means and the
charcoal-filter-means are separated by a volumetric region that is
sealed within the bacteria-impermeable barrier such that the
volumetric region acts as an interim destination for the airflow to
enter after leaving the entrapment filter means.
[0161] Preferably, the entrapment filter means and the
charcoal-filter-means are generally parallel to one another such
that the volumetric region therebetween is a flat and
planar-like.
[0162] Preferably, in use, the airflow leaves the entrapment filter
means and enters the charcoal-filter-means in a manner that the
airflow is substantially perpendicular to the surfaces of each of
the filter-means.
[0163] Preferably, the entrapment filter means and the
charcoal-filter-means are followed next, in sequence, by an
emitting-filter-means containing a beneficial emittable-substance
which, in use, is infused into the airflow expelled from the
filtration arrangement.
[0164] The entrapment filter means and the charcoal-filter-means
may be followed next, in sequence, by two or more
emitting-filter-means each containing a different beneficial
emittable-substance which, in use, is infused into the airflow
expelled from the filtration arrangement.
[0165] The beneficial emittable-substance may include a
pharmaceutical that is able to be administered to a user in an
airborne manner.
[0166] The beneficial emittable-substance may include a
fragrance.
[0167] The beneficial emittable-substance may include an
anti-bacterial substance.
[0168] Preferably, the beneficial emittable-substance is combined
with an air-flow activated composition described below, wherein the
beneficial emittable-substance is the active substance.
[0169] At least the emitting-filter-means may be in the form of a
flat piece of filter material that is supported in the filter
arrangement such that the flat piece is able to flutter in the
airflow.
[0170] Preferably, the bacteria-killing substance is a
liquid-applied substance which, when on the fibre, presents a
sticky coating on the fibre which captures bacteria that impinges
on the bacteria-killing substance found on the fibres.
[0171] Preferably, the sticky coating is able to physically hold
impinging bacteria particles to the fibre so that the bacteria are
held and killed in that location.
[0172] Preferably, the charcoal filter-means is a fibrous matrix
infused with charcoal particles.
[0173] Preferably, the charcoal-filter-means re-oxygenates the
airflow and removes odours.
[0174] Preferably, each of the filters is housed in a
filter-holder, and where each of the filter-holders is provided
with attachment-sequence-means that ensure that the filters can
only be attached one to the other in the aforesaid sequence.
[0175] Preferably, when each of the filters holders is attached to
one of the other in the aforesaid sequence, the filter-holders
combine to provide said bacteria-impermeable barrier.
[0176] Preferably, the attachment-sequence-means on each
filter-housing is in the form of a shaped contour that can only
mate precisely with a corresponding contour on the filter-housing
that is next in the aforesaid sequence.
[0177] Preferably, the filter-holders fit together in the aforesaid
sequence to form a stack.
[0178] Preferably, the fibrous matrix is adapted to physically
capture bacteria particles and, at the same time, also to present
minimal impedance to the airflow, and, as such, the fibrous matrix
is therefore characterised by:
[0179] average gaps or pores between the fibres that are very
significantly larger than the size of bacteria so as to present
minimal impedance to the airflow; and
[0180] a tortuous path for the airflow created by the fibrous
matrix so that the bacteria particles have an extremely high
probability of impacting at least some of the fibres of the
matrix.
[0181] Preferably, the average gaps or pores between the fibres is
selected to be around 150 microns.
[0182] According to a twelfth aspect of the present invention,
there is provided an air-flow activated composition including:
[0183] an active substance capable of becoming airborne at least
for a useful period of time; and
[0184] a release agent to restrain the active substance from
becoming airborne at normal room temperature and pressure,
[0185] wherein upon exposure of the composition to flowing air, the
release agent will release the active ingredient into the air
stream.
[0186] Preferably, the active substance is a biocide and/or a
fragrance.
[0187] Preferably, the release agent is a microporous polymer.
[0188] The release agent may be a microcapsule polymer shell.
[0189] The release agent may be a melamine-formaldehyde
microencapsulate shell.
[0190] The shells may range in size between 5-100 .mu.m
micrometers.
[0191] Preferably, he composition is sprayed on to the substrate in
a liquid emulsion.
[0192] There is provided a filter, installed in an air blowing
device whereby air passed over or through the filter whereby to
release the active substance.
[0193] Other preferred or optional features of this twelfth aspect
of the invention are summarised and described towards the end of
the specification, rather than at this point in the specification,
merely for the sake of clarity, so that in the specification, the
chemical aspects of the invention may be, as far as possible,
separated from the mechanical aspects.
DRAWINGS
[0194] In order that aspects of the present invention might be more
fully understood, embodiments of each aspect of the present
invention will be described, by way of example only, with reference
to the accompany drawings, in which:
[0195] FIG. 1A is a bottom perspective view of an embodiment of a
sterilising hand-drying apparatus, shown with its secondary filter
arrangement depicted in exploded view--the embodiment is shown as
it would be viewed from below when mounted on an upright surface,
such as a wall;
[0196] FIG. 1B is an upper perspective view of the same embodiment
of FIG. 1A, except with the apparatus shown opened up to reveal its
internal components inside the housing, and the main filter
arrangement positioned on the fan-casing;
[0197] FIG. 1C shows a front view of a baseplate for the embodiment
of FIGS. 1A and 1B, and shows the baseplate as it would appear,
face on, when mounted on an upright surface, such as a wall;
[0198] FIGS. 2A and 2B show side views of the embodiment of FIG.
1A, with FIG. 2A showing the apparatus with the housing in a closed
arrangement, and FIG. 2B showing the same apparatus with the
housing in an opened arrangement. (Certain internal components are
shown in FIGS. 2A and 2B using dotted lines. Details of most of the
internal components inside the hood, however, have been omitted
from FIGS. 2A and 2B for the sake of clarity);
[0199] FIG. 3 shows an exploded view of a first embodiment of a
filter arrangement of the main filter that is used in the main
aperture in the embodiment of FIG. 1A;
[0200] FIG. 4 is a bottom perspective view of the fan-casing that
is seen in FIG. 1B, except that here the fan-casing is shown
separately to reveal its underside and the heating elements. Also
shown in FIG. 4 is an exploded perspective view of components of
the embodiment of the main filter arrangement shown relative to
where these fit into the main aperture of the fan-housing;
[0201] FIG. 5 is a simplified block diagram of electrical circuitry
elements of an embodiment of the hand drying apparatus;
[0202] FIG. 6A illustrates a see-through perspective view of a
further modified embodiment which has a filter-replacement
mechanism that continuously or intermittently feeds a sheet-like
filter material across an aperture in the housing;
[0203] FIG. 6B is a modification of the embodiment of FIG. 6A;
[0204] FIG. 7A shows an exploded side view of a second embodiment
of a main filter arrangement that can be used to fit into the main
aperture of FIG. 4;
[0205] FIG. 7B shows an assembled side view of the filter
arrangement of FIG. 7A;
[0206] FIG. 8A show an exploded view of a third embodiment of a
main filter arrangement, having three filter components, compared
to the two components of the embodiment of FIGS. 7A and 7B;
[0207] FIG. 8B shows an assembled side view of the filter
arrangement of FIG. 8A;
[0208] FIG. 8C shows a fourth embodiment of a main filter
arrangement having four filter components;
[0209] FIG. 8D shows an assembled side view of the filter
arrangement of FIG. 8C having four filter components;
[0210] FIGS. 9A and 9B show an embodiment where filters pieces are
installed inside their filter housings, with FIG. 9A shown when
there is no airflow, and FIG. 9B shown when an airflow passes
through;
[0211] FIG. 10A shows yet a further embodiment of a filter
arrangement used with a hair drying apparatus;
[0212] FIG. 10B shows a modification of the embodiment of FIG. 10A,
with the modification being that the filter arrangement has an
additional substance-effusing filter;
[0213] FIG. 10C shows another modification of the embodiment of
FIG. 10A, having a four-filter arrangement similar to that shown in
FIG. 8C;
[0214] FIG. 11A shows yet another embodiment of a filter
arrangement used with a vacuum cleaner;
[0215] FIG. 11B shows another modification of the embodiment of
FIG. 11A, having a four-filter arrangement similar to that shown in
FIG. 8C;
[0216] FIGS. 12A, 12B and 12C show a different embodiment of a
filter arrangement, in front, side and exploded side views
respectively, used with an air-circulation fan;
[0217] FIGS. 12D and 12E show a further embodiment of a filter
arrangement used with a fan, having a four-filter arrangement that
has a similar function to that of the embodiment in FIG. 8C;
[0218] FIG. 13 is a simple schematic diagram of an embodiment of a
filter arrangement incorporated in a clothes dryer; and
[0219] FIG. 14 is a simple schematic diagram of an embodiment of a
filter arrangement incorporated in a refrigerator.
[0220] It is noted that FIGS. 6A and 6B have been drawn with
minimum detail, only showing details of embodiments of a
filter-replacement mechanism. For the sake of simplicity, other
internal details of the dryer have been omitted from FIGS. 6A and
6B, and likewise for FIGS. 13 and 14.
[0221] In the drawings of different embodiments, like elements have
been shown with like reference numerals, merely for ease of
understanding the various embodiments.
[0222] The embodiments are intended to kill a full spectrum of
bacteria, germs and the like, and the terms bacteria or germs are
used in a general sense, and should not be construed narrowly from
any biological definitions that would otherwise limit the invention
to killing a certain type of harmful micro-organism.
DESCRIPTION OF EMBODIMENTS
[0223] Referring to the accompanying drawings, FIG. 1A shows a
sterilising hand-drying apparatus in the form of a hand dryer
1.
[0224] The dryer 1 draws in and expels an airflow into a
human-activity environment frequented by people, such as a toilet,
or in a washroom such as in a hospital, to name but a few
examples.
[0225] The hand dryer 1 is adapted to emit or expel an airflow or
stream of substantially sterilised, heated air 200 C for drying
hands. In the exemplary embodiment, the operational range of the
heated air is around 55 to 65 degrees Centigrade.
[0226] The hand dryer 1 has a housing which includes a main hood 10
and a base-mounting in the form of a baseplate 11. The baseplate 11
is best seen in FIGS. 1B and 1C, and also in FIGS. 2A and 2B.
[0227] In FIG. 1B, the hood 10 is mounted to the baseplate 11 by
hinges 12.
[0228] The hinges 12 are designed such that the hood 10 can be
detached or removed from the baseplate 11. This enables the hand
dryer 1 to be installed in the simple two-step process: firstly,
the baseplate 11 is mounted to an upright surface such as a wall,
and secondly, the hood 10 is attached to the hinges of the
baseplate 11.
[0229] The baseplate 11 is secured to the wall with screws 13,
bolts or other appropriate fastening mechanism.
[0230] FIG. 1A shows the hood 10 arranged in a closed position,
which is the arrangement when the dryer 1 is in installed in
location.
[0231] FIG. 1B shows the hood 10 arranged in an opened
position.
[0232] In both FIGS. 1A and 1B, the orientation of the dryer 1 has
been drawn as it would be when mounted on a wall.
[0233] In a commercial embodiment, the hood 10 is locked to the
base-plate 11, and requires a special key 16A to unlocked the lock
16B, as seen in FIGS. 1A and 1B.
Air-Flow
[0234] As an overall summary, when the dryer 1, in use, is operated
to dry a user's hands, air from the ambient environment is drawn or
sucked into the housing, and then heated, and expelled, in that
sequence. The path of this airflow is notionally depicted by arrow
200A in FIG. 1A, then arrow 200B in FIG. 1B, and finally arrow 200C
in FIG. 1A. Of course, the actual flow of the air in the dryer 1 is
much more complex and turbulent, and so the arrows 200A, 200B, 200C
are a simplification for the sake of illustration.
Air Heater
[0235] In FIG. 4, the dryer 1 is provided with heating-means in the
form of a heating element 300. The heating element 300 is located
at an opening of the fan-casing 400, and is shown more clearly in
the separate bottom perspective view of the fan-casing 400 in FIG.
4.
[0236] The heating element 300 includes a grid of wires or plates
adapted to be heated up electrically when the dryer 1 is emitting
the hot airflow.
[0237] Regarding FIGS. 1B and 4, the heating element 300 is
positioned inside in the housing 10, 11, and is used to heat up the
airstream 200B so that the air is sufficiently warm to dry the
user's hands.
Inlet-Means
[0238] The dryer 1 has an inlet-means through which the air, in
use, enters the housing 10, 11 and travels to reach the heating
element 300.
[0239] In the embodiment, the inlet-means is regarded as a region
or passage through which the air travels to reach the heating
element 300.
[0240] In FIG. 1B, the inlet-means encompasses quite a range of
components and features in the embodiment of FIG. 1B. To begin
with, the inlet-means includes a secondary filter assembly 520A,
520B, 520C through which air enters the housing.
[0241] The inlet-means also include the cavernous interior of the
housing 10, 11. The air flows through the secondary filter assembly
520A, 520B, 520C and then into the interior of the cavernous
interior of the housing 10, 11.
[0242] The inlet means also includes a main-entrance 405 located in
the side of the fan-casing 400. Into this main-entrance 405 is
inserted a main airborne-bacteria filter arrangement in the form of
main-filter assembly 410A, 410B, 410C (and other embodiments
described below).
[0243] An exploded view of a first embodiment of the main filter
assembly 410A, 410B, 410C is shown in FIG. 3.
[0244] FIG. 4 shows the embodiment of the main filter assembly, in
relation to where it fits into the main entrance 405 of the
fan-casing 400.
[0245] In FIG. 4, the main filter assembly preferably includes a
base element 410A that fits directly into the main entrance or main
aperture 405. In FIG. 7B, the base element 410A is provided with
several resilient claws 408 that enable the base element to engage
and lock with the main aperture 405.
[0246] FIG. 3 shows an exploded view of parts of the main filter
assembly 410A, 410B, 410C.
[0247] In FIGS. 3 and 4, a bacteria entrapment filter-means in the
form of a filter material 410B is attached to the filter holder
410C. The filter holder 410C is able to engage with the base
element 410.
[0248] The filter material 410B is provided with slits which are
used to mount the filter on the filter holder 410C. In use,
protruding pins 411 on the filter holder 410C, pass through the
slits in the filter, as seen in FIG. 4 and best in FIG. 7B.
[0249] Each of the filter holders 410A, 410C has a coarse mesh 414
that is also limits the movement of the filter material 410B in
place.
[0250] The base element 410A and the filter holder 410C are
provided with corresponding bayonet mounting parts, that enable
these parts to fit together with a bayonet-style engagement. In
other embodiments, other forms or styles of engagements mechanisms
can be used, such as inter-fitting pins or press fit mounting, or
press-and-lock mountings.
Outlet-Means
[0251] The dryer 1 has an outlet-means through which the air, after
being heated by the heating element 300, is emitted as a heated
airflow 200C that is used for drying hands.
[0252] In the embodiment, the outlet-means is regarded as region or
passage through which the air travels away from the heating element
300 until it is expelled from the dryer 1.
[0253] In FIG. 1A, the heating element 300 is located inside a
projecting snout-like opening 14 on the front of the hood 10.
Hence, in the exemplary embodiment, the outlet-means is rather
short in overall distance, compared to the distance the air has to
travel through the inlet-means.
[0254] The heated air, that flows past the heating elements 300,
exits the housing almost immediately through the opening 14.
[0255] The opening 14 has a grille 15 which prevents the user's
fingers from touching the heated parts of the heating element
300.
Fan
[0256] The airflow 200A, 200B, 200C through the dryer 1 is created
by airflow-generation-means in the form of a rotating fan 401, seen
in FIG. 4. The fan 401 is in the form of a rotor that revolves
inside the fan-casing 400. Inner portions of the circular fan 401
can be seen in FIG. 4. The generally circular shape of the
fan-casing 400 accommodates the circular fan 401. The rotation of
the fan 401 is operated by a motor 430, seen in FIG. 1B. In the
example, the motor is a 125 watt, 7500 rpm universal motor. The
casing of the motor 430 is sealed to avoid bacteria entering the
airflow in the fan-casing 400 via any gaps in the casing of the
motor 430.
[0257] The rotating fan 401, located in the fan-casing 400, is
adapted to move the air swiftly as an airflow. The airflow enters
into the housing via the initial secondary aperture 520D and its
secondary filter assembly 520A, 520B, 520C, then through the
cavernous interior of the housing 10, 11, and then through the main
aperture 405 and through the main-filter assembly 410A, 410B, 410C
until the airflow reaches the heating elements 300. Then, the
airflow or air current, generated by the fan 401, is expelled from
the housing as a heated airflow 200C that is able to be used for
drying the user's hands.
Location of the Main Filter Arrangement
[0258] The inlet-means of the dryer 1 includes at least one "main
entrance" in the form of a main aperture 405. This main aperture is
intended as the only entrance for air and bacteria to enter the
fan-casing 400.
[0259] The notion of a "main entrance" is that all the airflow that
is emitted from the dryer has to finally pass initially through
this main entrance. In the embodiments, an opening would be defined
to be a "main aperture" or "main entrance" if literally all the air
in the airflow that comes out of the dryer, at some point, has to
pass through that aperture or entrance.
[0260] By placing an effective bacteria-entrapping filter on the
one or more main entrances, it ensures that all airflow coming out
of the dryer is intercepted by a bacteria-entrapping filter.
[0261] In the embodiment, the main aperture 405 is located on the
fan-casing 400. The main aperture 405 is in an opening in the
fan-casing 400, such that all air that enters the fan-casing 400
has to pass through this final filter 410B. After the airflow
enters the fan-casing, there is only one exit 14 out of the
apparatus 1. Therefore, this aperture 405 is regarded as a "main
entrance" because, apart from this, there is no other entrance into
the fan-casing. In other words, there is no other path that leads
to the final exit 14.
[0262] As an aside, to make the definition of an "main entrance"
more understandable, for example, the secondary entrance 520D, in
FIG. 1A, cannot be regarded as a "main entrance" because there
could be numerous other ways for air to enter the apparatus. For
instance, bacteria could bypass the secondary filter 520D when the
hood 10 is opened, or even enter through gaps in the hood 10 and
baseplate 11 when the hood 10 is closed. For example, when the hood
10 is opened, bacteria-laden ambient air of the toilet floods into
the interior of the apparatus 1. Also, in between the entrance 520D
and the final exit 14, there are numerous internal surfaces inside
the apparatus 1 which, over months or years of use, can become
infested and act as sources of bacteria. The secondary filter 520B
would not intercept this extraneous bacteria that enters the
airflow through other ways, such as the opened hood or from
internal surfaces, but the final main filter 410B would stop such
extraneous bacteria. That is why the secondary entrance 520D is not
regarded as a "main entrance", and why the secondary filter 520B is
not regarded as a "main filter".
[0263] The main entrance, in the form of main aperture 405, can be
seen in FIG. 4. In the illustration in FIG. 1B, this main aperture
405 is obscured because the main filter assembly 410A, 410B, 410C
is shown inserted into this main aperture 405 in the
fan-casing.
[0264] This main filter-assembly 410A, 410B, 410C intercepts the
airflow before the airflow reaches the heating element 300. The
main aperture 405 is the point in the airflow where all the airflow
in the dryer must pass through if it is to be expelled from the
dryer. Here, bacteria particles are finally entrapped and thus
stopped from entering the fan-casing 400. Preferably, the rest of
the casing 400, 430 is sealed such that air cannot enter, for
instance, through the motor casing 430.
[0265] By placing the main filter arrangement 410A, 410B, 410C at
the final point of entry into the fan-casing, it acts as the last
possible line of defence. It ensures that all the bacteria, that
might have remained in the airflow, is intercepted by the main
filter 410B. Even if bacteria enters the machine unexpectedly
through gaps in the walls of the apparatus, or from long-term
bacteria accumulation inside the apparatus, such bacteria cannot be
expelled through the emanating airflow 200C from grille 15, because
any airflow leaving the apparatus must finally pass through the
main filter arrangement 410A, 410B, 410C.
[0266] Thus, the identification of the main entrance, and the
location of the main filter arrangement at that final entry point
405 to the fan-housing, is a feature that contributes to the
ability of the apparatus 1 to achieve 100% removal and destruction
of bacteria in the airflow 200C that emanates from the drying
apparatus 1.
[0267] It is believed that, in the prior art, achievement of 100%
bacteria removal would be difficult, if no consideration is given
to addressing the fact that the internal surfaces inside the
apparatus are also a potential source of bacteria. Every internal
surface and part inside the apparatus is a potential source of
contaminants. For example, internal-painted surfaces can give off
toxins, and also the airflow can cause debris to come off internal
parts after years of use. In the prior art, a filter that is
positioned very early in the airflow path would not guard against
bacteria coming off internal surfaces that are downstream of the
filter.
[0268] Hence, in the embodiment, it is preferred that the final
main filter 410B is located directly on the fan-housing, so that
all of these extraneous contaminants and bacteria, upstream in the
airflow, can be caught and intercepted by the final and main filter
arrangement 410A, 410B, 410C before it enters the fan-housing. The
main filter arrangement is located at the last possible location
before the airflow reaches the heating element 300 and the exit
point 15. (It would be inconvenient to place the filter inside the
fan-housing, because this could not easily be replaced, and a
filter that is not easily replaced can, over time, itself become a
source of contamination).
[0269] In the embodiment, the main aperture 405, and the associated
main filter assembly 410A, 410B, 410C, are located totally inside
the apparatus housing 10, 11. This ensures that users cannot access
the main filter assembly, and that it can only be accessed and
replaced by authorised personnel.
[0270] In other modifications, there may be more than one or more
main apertures 405 located on the fan-casing 400, but in such
modified embodiments, it is still required that all air entering
the fan-casing 400 has to pass through these one or more
main-apertures 405 on the fan-casing.
[0271] In the present embodiment, even if bacteria were to enter
through gaps in the housing 10, 11, the location of the main filter
410B on the fan-casing, being the only entrance leading into the
fan-casing, ensures that this main filter 410B can intercept all
bacteria that enters the fan-casing 400.
[0272] In the embodiment of FIG. 1A and 1B, the main entrance 405
is located in an entrance leading into the
airflow-generation-means, or in other modifications its actual
location can be modified, provided that all air entering the
airflow-generation-means passes through this final entrance.
[0273] In the embodiments, the main aperture (or main apertures) is
only located on or connected to the fan-casing 400, such that all
airflow entering the fan-casing has to pass through this main
aperture. This is the preferred and best location, as shown in the
embodiment of FIG. 1A.
[0274] Another factor in designing the embodiment is that the main
aperture, which is the main and only opening into the fan-casing
400, should preferably not be accessible from the outside of the
dryer 1. For instance, the main aperture 405 into the fan casing
400 cannot be accessible from the outer surface of the hood 10,
otherwise it would enable unauthorised users to have access into
the moving parts and the electrically-wired parts of the hand dryer
apparatus 1. It would also offer vandals an opportunity to insert
harmful matter into the motorised parts of the apparatus, and even
squirt water into the fan and motor. All these possibilities would
pose a danger to users of the dryer 1.
Bacteria-Entrapment
[0275] Bacteria is actually comprised of extremely minute,
microscopic particles. The dryer 1 of the present embodiment is
provided with bacteria-entrapment-filter-means. In other words, a
means for trapping the bacteria particles so that the air which is
emitted from the dryer 1 is actually free from or devoid of the
bacteria particles. The focus is not just on killing the bacteria,
but also on entrapping the bacteria particles.
[0276] In the present embodiment, in FIG. 3, the
bacteria-entrapment-filter-means of the main-filter assembly 410A,
410B, 410C includes the filter material 410B which is a fibrous,
dense, generally non-uniform matrix of filter material that is
sufficiently dense to intercept and entrap a substantial portion of
the bacteria particles in the airflow. The fibres act as a physical
obstacle to the passage of the bacteria particles.
[0277] In the embodiment, it is found that the filter material 410B
ideally needs to be replaced around once per month, given its
regular use, for instance, in a typical public toilet facility,
since there would be a build-up of bacteria particles in the filter
material.
Filter Material
[0278] In the exemplary preferred embodiment, the filter material
is a melded, non-woven fibrous material. Non-woven fibres are
preferred because it is found that woven materials are less
suitable, with their tighter weave, which tend to restrict airflow
more than non-woven fibrous materials.
[0279] The filter material in the embodiment of FIG. 1A is a
non-woven, needle-felt, polyester fibrous pad of material, which
has the following characteristics:
TABLE-US-00001 Weight (gsm) 150 ISO 9073-1: 1989 Thickness (mm) 1.4
mm to 1.8 mm ISO 9073-2: 1995 Tensile Strength ISO 9073-3: 1989
(N/50 mm): Machine Direction 165 Cross Machine 165 Direction Air
Permeability 2,500 ISO 9230 @ 20 cm.sup.2/ (l/sec/m.sup.2) 200
Pa
[0280] In another preferred sample of filter material, a
determination of air permeability was conducted according to
Australian Standard AS 2001.2.34-90. The results were that the
preferred sample of filter material had an air permeability of
234.7 cm3/cm2/sec, with a coefficient of variation of 5.9.
[0281] The filter material is a melded polyester fibrous matrix
that has a totally random weaving matrix, or random lay. Thus, the
bacteria particles in an airstream, that pass through this fibrous
matrix, have to pass through a tortuous flow-path to navigate
through the random, fibrous matrix, thus increasing the likelihood
of each bacteria particle impacting and being entrapped by or on
one of the fibres.
[0282] It is often a compromise between choosing between the
conflicting requirements of a dense filter to assist in bacteria
capture, versus a less dense filter to ensure faster airflow.
[0283] The problem is this: an increase in the denseness or
thickness of the filter would, on one hand, more effectively
capture the bacteria particles, but, at the same time, would also
slow down the airflow through the filter, which can cause the
fan-motor to overheat. Therefore, some experimentation may be
required to find the appropriate denseness of filter material used
with the particular powered motor and fan for a given embodiment,
if it is desired to achieve the preferred object of 100%
bacteria-interception. For instance, with a more powerful fan that
produces a stronger airflow, a denser and/or thicker filter
material may be used.
[0284] The filter mesh weight in gsm (grams per metre square) gives
an indication of the nature of the average size of gaps in the
filter mesh.
[0285] For example, it was found that a fibrous matrix of a 50 gsm
material adequately entrapped bacteria particles, but the 50 gsm
fibrous material was found not to provide sufficient airflow to the
fan 401.
[0286] In the prior art, there is tendency to attempt to achieve
bacteria-filtration by selecting extremely fine filter meshes. The
notion in the prior art is similar to that of a net for catching
fish, where the mesh size has to be sufficiently small to match the
size of the bacteria. That creates a problem because, as mesh size
decreases, so does the ability of the airflow the pass through at
high speeds. This problem is not readily acknowledged in known
prior art that refers to very fine sterilising filters, without
realising the problems that can be associated with extremely fine
filter mesh sizes.
[0287] The present embodiment recognises the issue of conflicting
needs. On one hand, it is desirable for the filter mesh to be
sufficient to catch the bacteria particles, but, on the other hand,
the mesh cannot be so small that it impedes optimum airflow.
[0288] In the present embodiment, the mesh size is selected as
being around a 150 micron weave, in the sense that the non-woven
material has average gaps or pores between the fibres of around 150
microns. This has been selected from the vast range of filter
materials as being in the size-region where very fast airflow is
achievable, while retaining the capacity to entrap 100% of the
bacteria. The ability to use a relatively large pore-sized 150
micron weave is made possible because the filter is used in
conjunction with a sticky liquid coating on the filter, described
below.
[0289] Without being limited by theory, it is postulated that a 150
micron weave might not have been recognised, in the prior art, as a
suitable mesh size for bacteria entrapment because the pores of a
150 micron weave are very significantly larger than the typical
size of bacteria particles. In the present embodiment, however, it
is recognised that when the fibres are coated with a sticky
anti-bacteria liquid, mesh sizes selected around 150 microns become
suitable, because the large pore sizes allow fast airflow, while
presenting a sufficiently tortuous and random flow-path that
ensures that 100% of the bacteria will impinge on one of the
fibres, and adhere thereto because of the sticky coating.
[0290] The weave, selected around 150 microns, thus, uses a
different mechanism to trap the bacteria. The bacteria are not
necessarily only caught between the gaps of two proximate fibres
(as per the analogy of fish caught in a net). Rather, the weave of
the fibrous matrix, at a 150 micron weave, is found to present a
sufficiently tortuous path, that the probability of a bacteria
hitting or colliding with a fibre is extremely high. Also, as will
be described below, the filter strands are coated with a sticky
material to ensure that the bacteria particles, which do collide
with a filter fibre, are more than likely to cling to the fibre,
rather than carry on with the airflow. In other words, in a filter
mesh or around 150 microns, the large gaps in the fibres enable the
airflow to move very quickly through the filter material. At the
same time, the density of fibres at 150 microns ensures that the
bacteria in the air are captured by the filter threads as the air
moves through the filter.
[0291] In other words, it is the nature of the fibrous material,
plus the sticky coating on the fibres, that combine to address both
the conflicting requirement of i) germ capture, and ii) airflow
speed.
[0292] While filters of around 150 microns are, of course, widely
available in the market for general use, it is the unforeseen
selection of a filter mesh around 150 microns that gives the
unexpected result of enabling both i) 100% germ capture and ii)
very high airflow speed. The selection of around 150 micron mesh is
unexpected because the large pore size is many multiple times
larger than the typical bacteria size. The selection, used for the
present embodiment, recognises that this seemingly large filter
pore size actually and unexpectedly becomes an ideal choice, if it
is combined with the sticky coating.
[0293] Some experimentation may be done to determine the upper and
lower limits of acceptability, in terms of plus-or-minus variance
from the 150 micron mark that can still achieve the dual and
unexpected benefits of enabling i) 100% germ capture and ii) very
high airflow speed.
[0294] The main filter material 410B traps and retains, in the
filter, a substantial portion of the bacteria particles in the
airflow. Thus, the airflow leaving the main filter 410B is more
sterile than when it enters the filter 410B.
[0295] In the above paragraph, the word "retains" indicates that a
substantial portion of the bacteria enters, but is unable to leave
the filter. In other words, the airflow leaving the main filter
410B has numerically fewer particles of bacteria than the airflow
entering the same main filter 410B.
[0296] A feature of the present embodiment, that has been verified
by independent microbiological testing, is that the airflow leaving
the filter 410B is fully 100% bacteria-free or at least
substantially bacteria-free and extremely close to the 100% mark.
In other words, the bacteria particles have not merely been
inactivated or killed, but have been physically removed from the
airflow to a very substantial degree.
[0297] An early experimental model of the embodiment was tested in
a male washroom of an industrial factory, in which aerial
contamination with different micro-organisms was verified to be
present. The airflow emanating from the dryer 1 was found to be
100% free of bacteria particles or pathogens. Thus, the
bacteria-entrapment-filter-means of the embodiment is able to trap
100% of the bacteria in the airflow, such that the airflow leaving
the bacteria-entrapment-filter-means is, or substantially close to
100% bacteria-free.
[0298] It would be evident, therefore, that the embodiment of the
present invention which can achieve the goal of 100% bacteria-free
hand drying would be arguably more hygienic for drying hands than
even disposable paper towels. For instance, the model which
achieves this close to 100% bacteria-removal would be suitable for
use by surgeons prior to attending to surgery.
[0299] Thus, in this aspect of the invention, the embodiment of the
dryer 1 is provided with a means of entrapping and retaining the
actual bacteria particles, so as to prevent the bacteria from
leaving the dryer in the warm airflow 200C. This is conceptually
different to air filters, used in prior art dryers, which merely
filter out larger particles such as dust and grit, and which are
not adapted or even intended to entrap the bacteria on a scale of
100% removal of the bacteria particles. Thus, any prior art that
recites merely an "air filter" should not necessarily be treated,
prima facie, as a prior disclosure of a
bacteria-entrapment-filter-means unless it teaches the actual
entrapment of the bacteria particles.
[0300] A broad premise of the embodiment is that, in order to kill
the bacteria effectively, the bacteria particles have to entrapped.
This is a different approach to those prior art sterilising dryers
that attempt to kill the bacteria while the bacteria is entrained
in the swiftly moving airflow, without first trapping and retaining
the bacteria particles. In experiments, it has been found that such
prior art systems are far less effective at removing bacteria from
the airflow, compared to experimental embodiments of the present
embodiment which, firstly, entrap the bacteria, and then secondly
kill the entrapped bacteria which is held motionless in the
filter.
[0301] In summary, the fibrous matrix is able to physically capture
bacteria particles and, at the same time, also to present minimal
impedance to the airflow. Hence, the average gaps or pores between
the fibres that are very significantly larger than the size of
bacteria so as to present minimal impedance to the airflow. Also, a
tortuous path for the airflow created by the fibrous matrix so that
the bacteria particles have an extremely high probability of
impacting at least some of the fibres of the matrix.
Example of Filter Material
[0302] As an example, the filter material used in the present
embodiment is a carded polyester spun-bond membrane with multiple
random fibres of 150 grams per metre square. The filter material
has a calliper thickness of 1.4 to 1.8 mm. This relatively large
pore size, in the 150 gsm filter material, allows a maximum air
velocity permeability of 2500 l/sec/m.sup.2.
[0303] This material, when in the dry state, provides a degree of
fibre entanglement with average gaps or pore sizes of around 30-40
microns. Thus, in a dry state, this material is inadequate for
achieving 100% bacteria capture, because the bacteria particles are
usually 0.3 to 30 microns, and viruses are between 0.01 and 0.05
microns. Hence, in its dry state, the 150 gsm filter material is,
in itself, unlikely to be suited to achieving the goal of 100%
capture rate or close to that. However, the selection of such an
apparently unsuitably large mesh size, when combined with the
sticky coating on the fibres, is unexpectedly able to be used in
achieving the goal of 100% capture rate, while still enabling fast
airflow speeds through the large pore sizes.
[0304] The added stickiness of the coated fibres enhances the
ability to entrap particles many times over the normally expected
capture rate that would be suggested merely from the 150 micron
pore size alone.
Bacteria-Killing Substance: Killing The Germs In The Filter
[0305] In the preferred embodiment, the filter material 410B is
coated with a bacteria-killing substance that is able to kill the
bacteria entrapped and retained therein.
[0306] The fibrous matrix has, on its fibres, a toxic
bacteria-killing substance which is able to kill any bacteria that
impinges on the bacteria-killing substance on the fibres.
[0307] Thus, a substantial portion of the bacteria, that is trapped
and retained in the filter, is also killed in the filter, on the
fibres. (If there were no anti-bacterial material in the filter,
the entrapment of bacteria particles would lead to an
bacterial-infestation in the filter material).
[0308] In the embodiment, it is an advantage that the germs or
bacteria are entrapped, and then killed while they are in the
filter. Otherwise, if the germs were merely entrapped, but not
killed, then bacteria levels in the filter would gradually increase
over time. Then, when the machine is turned off or not in
operation, bacteria on the filter would grow, such that the filter
itself would become a source of bacteria that could spread
throughout the apparatus to infect the internal surfaces.
[0309] The anti-bacteria material, which is used to kill the
bacteria, may be in the form of liquid or gel, provided it performs
the role of killing the bacteria that is entrapped in the
filter.
[0310] In practice in the embodiment, the bacteria-killing
substance is sprayed onto the fibrous filter material within an
alcohol-based liquid spray. When the alcohol evaporates, the
bacteria-killing substance remains on the fibrous, random
matrix.
[0311] In the embodiment, the bacteria-killing substance is a
liquid-applied substance. When the bacteria-killing substance is
applied as a liquid to the fibre, it forms a sticky coating on the
fibre which aids in the capture of bacteria that impinges on the
bacteria-killing substance found on the fibres. The sticky coating
is able to physically hold the impinging bacteria particles to the
fibre so that the bacteria are held and killed in that
location.
[0312] It is appreciated that any number of anti-bacterial
materials or liquids can be used to kill the bacteria particles
that are entrapped in the filters 410B, 520B. In the present
embodiment, the substance is manufactured by Healthguard
Corporation of Campbellfield, Victoria, Australia, bearing product
code: AFA-BK, 9-260.
[0313] In the embodiment, the entrapment filter 410B should be
changed each month, since the potency of the anti-bacterial sticky
material on the filter does not maintain its effectiveness for
extended periods.
Further Modifications: Filter Arrangement
[0314] In the first embodiment of FIG. 4, there is one main filter
410B in the main-filter assembly. In that first embodiment, while
the anti-bacteria material kills bacteria that impinges on the
filter 410B, a disadvantage is that traces of the anti-bacteria
material can remain in the airflow, and exit the filter into the
atmosphere of the human-activity environment. Although these minute
trace amounts anti-bacteria material are unlikely to be dangerous
to the average person, these can be highly dangerous to some
people, particularly those who suffer from respiratory or lung
ailments. For example, people who suffer from cystic fibrosis can
be harmed by even trace amounts of toxic materials in the
atmosphere.
[0315] The anti-bacteria liquid, when it is at the level of potency
that can kill 100% of the typically most virulent bacteria, tends
to be very poisonous and harmful to humans. For example, it is
potentially an eye-irritant.
[0316] The bacteria-killing substance is required to be highly
toxic in order to kill the bacteria, but preferably the toxins need
to be removed from the airflow.
[0317] In order to remove any trace amounts of toxic material from
the airflow, FIGS. 7A and 7B show that the main fibrous filter
410B, which has the a toxic bacteria-killing substance, is followed
in sequence by a charcoal or carbon filter-means. In the
embodiment, the charcoal filter-means is the form of a
charcoal-infused fibrous or porous filter material 410D that is
infused with charcoal or carbon particles.
[0318] The charcoal or carbon particles, in the charcoal-infused
filter material 410D, intercept and remove from the airflow any of
the toxic bacteria-killing substance that originates from the
coating on the entrapment filter 410B. This ensures that the
airflow leaving the main filter assembly is substantially free, not
only of bacteria particles, but also of traces of the
bacteria-killing substance.
[0319] Removal of the bacteria-killing substance from the airflow,
as mentioned above, enables the apparatus 1 to be used in
human-activity environment where there are people with very
sensitive lung conditions, such as in hospitals.
[0320] Also, since the bacteria-killing substance is removed from
the airflow, this allows the option to use of much more highly
potent bacteria-killing substances on the first fibrous filter
410B. This because, without the subsequent charcoal filter 410D, it
would have been necessary to refrain from using extremely toxic
materials in the first filter 410B, for fear that the greater
toxicity in the airflow might harm people in the surrounding
environment. Whereas, with the subsequent charcoal filter 410D, the
use of much more highly toxic substances in the first filter 410B
enables the apparatus to achieve greater effectiveness in its
bacteria-killing capacity. In the embodiment, this ability to use
much more highly toxic materials, due to the presence of the
charcoal filter, contributes to the ability to achieve a 100%
bacteria-free airflow emanating from the apparatus 1.
[0321] Furthermore, without being limited to theory, it is believed
that the charcoal re-oxygenates the airflow as it flows through the
charcoal-infused filter 410D.
[0322] Thus, the charcoal is believe to have the dual roles of,
firstly, removing the toxic anti-bacterial chemical, and, secondly,
re-oxygenating the airflow. The charcoal is also believed to remove
malodours and smells from the airflow.
[0323] In the embodiment, a fibrous filter material 410D is infused
with charcoal particles or powder, however, in other modifications,
highly porous pieces of charcoal or charcoal-infused material, may
also be used, provided the porosity is sufficient to not
substantially impede the airflow velocity.
[0324] In the embodiment, it is not intended that the charcoal
filter 410D be primarily used to trap and kill the bacteria. The
step of trapping and killing the bacteria is performed in the first
entrapment filter 410B. Hence, the airflow that comes from the
entrapment filter 410B would have reached the 100% bacteria free
level, or at least virtually at that level, at the point where it
enters the charcoal filter 410D.
[0325] In fact, charcoal or carbon is believed to be an inferior
material for trapping and killing the bacteria. Without being
limited by theory, it is believed that the charcoal is not as
suitable a substrate on which to place the bacteria-killing
substance, perhaps because the bacteria-killing substance may be
absorbed inside the charcoal particles, rather than letting the
bacteria-killing substance remain on the surface to be available to
kill the bacteria. Also, it is postulated that the charcoal
particles may contaminate the bacteria-killing substance, which, in
the embodiment, is a liquid or liquid-applied substance. In
summary, the charcoal filter 410D in the embodiment is not adapted
to perform the step of killing the bacteria.
[0326] Since the charcoal filter 410D, in the embodiment, does not
contain the sticky anti-bacterial liquid coating, the 100% removal
of bacteria from the airflow should have been achieved before the
airstream reaches the charcoal filter 410D. If not, then it implies
that some bacteria could be reaching the charcoal filter, and this
bacteria could multiply when the airflow is not operating. That
could lead to the charcoal filter, over time, turning into a source
of bacteria. Hence, the 100% removal of bacteria must occur before
the airflow reaches the charcoal filter.
Filter Housing--Bacteria Cannot Enter
[0327] In the second embodiment of FIG. 7A (in similar manner to
FIG. 4), the base element 410A of the filter assembly is adapted to
fit directly into the main entrance or main aperture 405 of the
fan-casing.
[0328] In the exploded view of FIG. 7A, the first filter holder
410C, in turn, fits onto the base element 410A, followed by a
second filter holder 410E which, in turn, fits onto the first
filter holder 410C.
[0329] FIG. 7B shows the components of FIG. 7A in an assembled
state. The assembled parts fit together with a bayonet-style
engagement, although other forms of attachment mechanisms are
possible in other embodiments.
[0330] In FIG. 7B, an arrow 409 shows the direction of the airflow
when the apparatus 1 is in use. In FIG. 7B, the filter arrangement
is provided with filter-barrier-means which, in the embodiment,
includes the walls of the filter holders which, when assembled, fit
very tightly together. It also includes the barrier created by the
interface of the lower edge of the base element 410A and the
fan-housing.
[0331] The walls of the filter holders 410C, 410E, when fitted
together in use, serve to house the main entrapment filter 410B and
the charcoal filter 410D. The net effect of the
filter-barrier-means is to provide a bacteria-impermeable barrier
for the filters 410B, 410D. This effective bacteria-impermeable
barrier separates the filters 410B, 410E from the interior of the
apparatus. This means that, when the airflow is blowing through the
apparatus 1 and even when it is not, bacteria or other contaminants
inside the apparatus can only enter the filter arrangement via the
face of the main filter 410B that directly faces the incoming
airflow. The contaminants and bacteria cannot pass through other
parts or joints of the filter arrangement.
[0332] In the embodiment of FIGS. 1A to 4, the airborne-bacteria
filter arrangement 410A, 410B, 410C, 410D, 410E is located fully
inside the interior of the apparatus 1.
[0333] When the base element 410A and the filter housings 410C,
410E are fitted together, bacteria cannot enter into the interior
of the filter arrangement through points of abutment of the
components 410A, 410C, 410E, due to the bacteria-impermeable
barrier that results from the tight fitting of the components. This
is an advantage because, potentially, the interior surfaces of the
apparatus 1, like any machine, are a potential source of
contaminants, whether from the materials from which they parts are
made, or from bacteria that enters the machine in spite of
safeguards described herein. Hence, the bacteria-impermeable
barrier prevents entry of bacteria through the sides or joints of
the filter assembly (410A to 410E).
[0334] Also, the same bacteria-impermeable barrier prevents any
live bacteria inside the filter arrangement from escaping into the
interior of the apparatus when the apparatus is turned off, or not
generating an airflow. For instance, bacteria might enter through
the grille 15, in FIG. 1A. For instance, when the apparatus is not
in use, the bacteria-impermeable barrier prevents bacteria from
entering into the interior of the apparatus. This avoids the
interior of the apparatus itself eventually becoming a source of
bacteria. (When the machine is turned off, the main filter 410B
prevents bacteria, entering via the opposite, end passage 14, from
reaching the internal regions of the apparatus. Once the apparatus
is turned on again and used, any bacteria in the end passage 14
would tend to be killed by the heat from the heating element
300).
[0335] This creation of the bacteria-impermeable barrier, in the
surfaces of the filter arrangement, complements the function of
other features of the apparatus which, individually and/or in
combination, act to prevent, as far as possible, bacteria from
entering into the interior of the apparatus. This is to avoid or
minimise a situation where the interior of the drying apparatus 1
could itself become a source of bacteria.
[0336] These features, which minimise the entry of bacteria into
the interior of the apparatus, contribute to the ability of the
apparatus 1 to achieve 100% bacteria removal from the airflow. In
other words, the prevention of bacteria entry into the interior,
even when the apparatus is not generating an airflow, is another
factor that can influence whether the apparatus, overall, is able
to achieve the goal of 100% bacteria removal.
[0337] It has been described above that the main filter arrangement
410A to 410E, in this embodiment, is positioned and located at the
final entry point to the fan-housing 400. In combination with this
fact, the provision of a bacteria-impermeable barrier for the main
filter arrangement, further ensures that bacteria cannot pass
through the main aperture 405 through gaps or joints in the filter
assembly, except and only through the front of the main filter
410B.
[0338] In other modifications, the mechanism for fitting the
components of the filter assembly together may be designed so that,
once fitted, the components cannot be pulled apart by the user.
Some form of locking mechanism may be provided. This is to ensure
that the user does not inadvertently open up the filter assembly,
thus releasing any bacteria therein. The intention, for such an
embodiment, is that the entire filter assembly 410A to 410E is
replaced periodically, as an entire unit. In the present
embodiment, it is recommended that the filter assembly be replaced
at least once a month.
[0339] It is noted that, in some cases, particularly in non-medical
ambient environments, the use of the charcoal filter may not
strictly be required. People with a general state of health may
tolerate the low trace levels of the bacteria-killing substances in
the airflow that emanates into the surrounding atmosphere.
Integral Unit: Replacing & Disposing of Filter and its
Components
[0340] From FIGS. 3, 7A, 7B, 8A, 8B, and 1B, the filter
arrangement, when assembled, is in the form of an integral and
single unit. In other words, all the relevant components of the
filter arrangement are contained in a single replaceable and
disposable unit. When the main filter 410B starts to become filled
with captured and killed bacteria particles, the entire main filter
arrangement can be removed as a single entity, and replaced. This
is an advantage because the ability to conveniently replace the
main filter assembly ensures that it does not itself become a
source of bacteria when the filter starts to be clogged with
bacteria particles that have been entrapped and killed. It is not
only the fibrous filter material that needs replacing, but also the
surrounding components that are also tainted by bacteria. Such an
advantage would not be present in prior art apparatus where
components are spread around the machine as separate
components.
Integral Unit: Replacing & Disposing of Internal Surfaces of
the Apparatus
[0341] This ability to remove and replace a single unit can be
appreciated in another light. Not only does this enable the
replacement of the filter elements 410B, 410D, but, just as
importantly, it enables the removal and replacement of the
"internal surfaces" 412 of the apparatus 1 that are closest to the
final entry point to the final aperture 405. It ensures that these
internal surfaces 412, themselves, do not, over months or years of
use, become coated with bacteria or other contaminants.
[0342] This recognises the fact that the design of an apparatus
must be assessed for its potential performance over years of use,
not just as it functions when new. Over years, the internal
surfaces of the machine can become contaminated with bacteria too.
That adds another factor to the difficulty of achieving 100%
bacteria removal from the airflow over the long term use of the
apparatus, which can be in operation for many years.
[0343] Thus, the ability to replace the critical internal surfaces
of the apparatus, that are closest to the final aperture 405 is
another factor in the embodiment that contributes to the ability to
achieve 100% bacteria removal, not simply in a new apparatus, but
over years of use.
[0344] In prior art apparatus, while the component that are spread
around the apparatus may possibly be removable, it is very
difficult to replace internal surfaces. In the present embodiment,
it is therefore an advantage that this sealed environment, created
within the main filter arrangement, can be removed and replaced as
a single unit. Critical internal surfaces, that lead towards the
final aperture, can be readily replaced. This ensures that the
internal surfaces, that are downstream of the final entrapment
filter 410B, do not themselves, over time, become sources of
bacteria.
[0345] In FIGS. 7B, 8B, 9A and 9B, the main entrapment filter 410B
and the charcoal-infused filter 410D are separated by a volumetric
region, in the form of a volumetric gap 413. The gap 413 is sealed
within the bacteria-impermeable barrier. The volumetric gap 413
acts as an interim destination for the airflow to enter after
leaving the entrapment filter 410B. Without being limited by
theory, it is believed that this confined volumetric gap 413 helps
to maintain the airflow within a confined area, rather than
diffusing over a wide cavernous volume that could add to air
turbulence and decreased airflow speed.
[0346] The main entrapment filter 410B and the charcoal-infused
filter 410D, when there is no airflow passing through, are
generally parallel to one another such that the volumetric region
therebetween is a flat and planar-like.
[0347] The airflow leaves the main entrapment filter 410B and
enters the charcoal-infused filter 410D in a manner that the
airflow is substantially perpendicular to the surfaces of each of
the filter-means.
[0348] In FIG. 7A, the height of the rim of each filter component
determines the distance of the gap 413 between each filter
component. It is believed that the distance between filter pieces
affects the ability of air to flow through the overall filter
arrangement. This is because the same filter materials 410B, 410D,
placed together as a single, thick sandwich of filter materials,
without gaps, would not allow the same speed of air-flow.
[0349] The charcoal filter 410D should be relatively close the
entrapment filter, so that substantially all the anti-bacteria
toxic material from the main filter 410B can be intercepted.
Otherwise, if the charcoal filter 410D were separated from the
entrapment filter 410B by a very great distance, then, over a
period of years, the internal surfaces of the apparatus in between
the main entrapment filter 410B and the charcoal-infused filter
410D could see a steady build-up of the toxic anti-bacteria
chemicals on its internal surfaces. Thus, it is an advantage for
the gap 413 to be as small as possible. A small gap 413 ensures
that the airflow coming out of the main filter 410B, will enter
almost immediately into the charcoal filter 410D, with less chance
of depositing the toxic anti-bacterial liquid on internal surfaces
of the apparatus.
Emitting a Substance
[0350] By way of brief review, the airflow enters the filter
arrangement via the entrapment filter 410B where the bacteria is
trapped and killed by the anti-bacterial liquid that is coated on
the fibres. Next, in sequence, the airflow coming out of the filter
410B enters a charcoal-infused filter 410D where any traces of the
anti-bacterial liquid, in the airflow, are removed.
[0351] In the third embodiment of FIGS. 8A and 8B, following after
the two filters 410B, 410D, there can an emitting-filter-means in
the form of an effusing filter 410F held in a third housing
410G.
[0352] The purpose of this effusing filter 410F is to add or infuse
into the airflow some emittable-substance that has some manner of
benefit. For example, the beneficial emittable-substance may be a
pharmaceutical that is able to be administered to a user in an
airborne manner. In one example, the pharmaceutical could be a
medicinal substance used by people who suffer from asthma.
Typically, people who suffer from asthma use an inhaler to breathe
in medicinal vapour, however, an embodiment of the present
invention can be used to infuse that substance into the ambient
atmosphere, so that the pharmaceutical can be breathed in
continuously in smaller trace amounts. This approach can be used in
relation to other breathing disorders, such as bronchitis and
sinusitis. Potentially, any ailment that is treated by a person
breathing in a vapour, can be delivered by effusing that substance
into the air.
[0353] Alternatively, the beneficial emittable-substance may be a
fragrance. This is useful when the apparatus 1 is used in
environments that have unpleasant odours, such as in public
toilets, where there is a need for air-freshening substances to be
infused into the atmosphere. This has particular application to the
field of aromatherapy.
[0354] In the case of a hand dryer used in medical fields or in
other washrooms, even though the highly toxic bacteria-killing
substances, that come from the main filter 410B, should preferably
be removed from the airflow, this subsequent effusing filter 410F
can emit a less-toxic anti-bacterial substance, which is less
potent compared to the highly toxic substance found on the
entrapment filter 410B. This less-toxic substance can be directed
onto the user's hands as the hands are dried. This would provide
additional anti-bacterial treatment for the hands.
[0355] In the embodiment, the use of a less-toxic anti-bacterial
substance, emitted from the effusing filter 410F, also performs an
added role of killing or minimising the amount of bacteria that
enters the apparatus 1 via the end-opening 14.
[0356] As described below, each beneficial emittable-substance can
be used in combination with a chemical release agent.
Fluttering Filter
[0357] FIGS. 9A and 9B show an embodiment where filters are
installed inside their filter housings, with FIG. 9A being when
there is no airflow, and FIG. 9B when an airflow passes
through.
[0358] In the embodiment, the filters, as mentioned, are in the
form of a flat piece of filter material that is mounted loosely on
a pin 411. The loose mounting of the filter on the pin is such that
the filter is able to flutter in the airflow, as shown
diagrammatically in FIG. 9B. Without being limited to theory, it is
believed that this fluttering of the effusing filter 410F assists
in effusing the emittable-substance, from the fibres of the filter
410F, into the airflow.
Acceptable Filter Sequences & Combinations
[0359] Various embodiments of the invention can have a range of
acceptable sequences and/or combinations of filters.
[0360] In all embodiments of the filter arrangement, a main
bacteria entrapment filter 410B is essential.
[0361] For certain medical environments, it is preferred that the
entrapment filter 410B is followed by the charcoal-infused fibrous
filter 410D, and in other human-activity environment where there
are people who may be adversely sensitive to even trace doses of
the highly toxic bacteria-killing substance used in the main
entrapment filter 410B.
[0362] In other embodiments, where there are unlikely to be many
people with adverse sensitivity to the trace doses of the toxic
bacteria-killing substances, the charcoal-infused fibrous filter
410D may be omitted. For example, in such cases, the effusing
filter 410F can follow after the entrapment filter 410B as the next
filter in sequence.
[0363] Also, in other environments, the effusing filter 410F may
not be required, and here it would be sufficient to have just the
entrapment filter 410B, and sometimes followed by the
charcoal-infused fibrous filter 410D, where necessary.
Filter Sequences & Combinations: Four Filters
[0364] FIGS. 8C and 8D show a fourth embodiment where the filter
arrangement includes four filters 410B, 410D, 410F, 410FF in
sequence.
[0365] In FIG. 8C and 8D, airflow through the filter arrangement
first encounters the main entrapment filter 410B and the
charcoal-infused filter 410D. Following these are two effusing
filters 410F, 410FF.
[0366] In the embodiments, when there are two or more effusing
filters, 410F, 410FF, each effusing filter preferably contains a
different beneficial emittable-substance.
[0367] For example, the next filter 410F in the sequence could
effuse a fragrance or perfume into the air, while the ultimate
filter 410FF in the sequence could emit the less-toxic
anti-bacterial substance.
[0368] Therefore, in the four-filter embodiment of FIG. 8C:
[0369] i) the bacteria in the airflow is entrapped by the filter
and killed by a poisonous, highly toxic anti-bacteria substance on
the first filter 410B;
[0370] ii) the poisonous anti-bacteria substance is removed from
the airflow by the charcoal-infused filter 410D;
[0371] iii) a fragrance or perfume from a penultimate effusing
filter 410F is evaporated into the airflow; and
[0372] iv) a mist of mild anti-bacterial substance is effused into
the airflow by the ultimate effusing filter 410FF, so that the
airflow emanating from the apparatus will contain a mild non-toxic
anti-bacterial substance.
[0373] It is noted that some substances are effused into the
airflow by the substance fully or substantially evaporating into
the airflow. In contrast, there are other substances that are
effused into the airflow as minute particles or a fine mist of
liquid. For instance, in the previous example, a perfume or
fragrance is likely to evaporate into the airflow, whereas effusing
some types of mild anti-bacterial substance into the airflow is
more likely to happen in the form of a fine mist entering the
airflow.
[0374] Therefore, when there are two or more effusing filters 410F,
410FF, and when one of these has an evaporating substance and the
other has a mist-creating substance, it is preferred that the
airflow first encounters the filter 410F with the evaporating
substance, followed by the filter 410FF that has the mist-creating
substance.
[0375] This sequence and arrangement is recommended because, if the
mist-creating substance were to be on the penultimate filter (410F
in FIG. 8A), then the mist is likely to be trapped or collect on
the ultimate filter (410FF) instead of passing out into the ambient
environment.
Filter Sequence Mechanism to ensure Acceptable Filter Sequences
[0376] In order to ensure that the components in the filter
arrangement are arranged or fitted together in the desired
sequence, each of the filter holders are provided with a mechanism
that can engage with another filter holder only in a predetermined
acceptable sequence. Each of the filter-holders 410C, 410E, 410G is
provided with attachment-sequence-means that ensure that the
filters can only be attached one to the other in the aforesaid
sequence.
[0377] The attachment-sequence-means on each filter-housing is in
the form of a shaped contour that can only mate precisely with a
corresponding contour on the filter-housing that is next in any one
of the acceptable sequences. In FIG. 7B, the
attachment-sequence-means is in the form of a bayonet-style mount.
The dimensions and position of the bayonet mount on each of the
housings 410C, 410E, 410G are designed to ensure that unacceptable
combinations cannot possibly occur, as described above.
[0378] For instance, the embodiment of the filter arrangement
cannot have the charcoal-infused fibrous filter 410D being the
first filter in the sequence. Hence, the filter housings 410C,
410E, 410G are designed with connectors that can only mate or
connect with another of the filter housings, in an acceptable
combination.
[0379] For example, an acceptable combination would be seen in FIG.
7B where the rear of the main filter housing 410C is able to mate
or connect with the front of the housing 410D for the
charcoal-infused filter.
[0380] In other embodiments, the attachment-sequence-means could be
in the form of pins on one filter housing that can only mate with
another of the filter housings when there is a corresponding
pin-hole. The location of the pins and pin-holes are located to
ensure that only the acceptable sequences of connection are
possible.
[0381] When each of the filters holders are attached one to the
other in an acceptable sequence, the filter-holders combine to
create the bacteria-impermeable barrier, discussed above.
[0382] The filter-holders also fit together in an acceptable
sequence to form a single stack, also discussed above.
Secondary Filter or Filters
[0383] In the embodiment of FIG. 1A and 1B, in addition to the main
filter assembly 410A, 410B, 410C and also preferably 410D to 410G,
it is preferable for the inlet-means to also include one or more
secondary filters arranged in series with the main filter
arrangement 410A to 410E/G.
[0384] In the embodiment in FIG. 1A, a secondary filter 520B
partially reduces the amount of bacteria in the airflow, but not
all of the airflow passes through the secondary filter. For
instance, in the embodiment, when there is no rubber strips to seal
the gaps between the hood 10 and the baseplate 11, some airflow can
enter the dryer 1 through these gaps, and, as a consequence, allow
entry of bacteria through the gaps. That is the reason why, in the
embodiment, the external filter 520B is regarded merely as a
"secondary filter".
Maintaining Airflow
[0385] Each of the one or more secondary entrances 520D is provided
with a bacteria-entrapment-filter-means (520B). It stands to reason
that having more than one filter increases the overall combined
"thickness" of filter material that the bacteria has to pass
through, thus increasing the likelihood of the bacteria being
entrapped by the filter material.
[0386] In the embodiment of FIG. 1A and 1B, the air, which enters
the housing 10, 11, eventually reaches the heating elements 300
after it passes through a series of apertures. (The initial
secondary aperture 520D is obscured in FIG. 1A, since this aperture
520D is shown with the secondary filter assembly 520A, 520B, 520C
in exploded view, indicating how the three parts of the secondary
filter-assembly fit into this aperture 520D).
[0387] The coarse mesh of the secondary filter holders 520A, 520C
are useful for filtering our large dust and other particles. Other
embodiments can have more than three layers comprised in the
secondary filter assembly.
[0388] The secondary filter 520B, located at this initial aperture
520D, stops a substantial portion of the bacteria particles
entering the inlet-means of the dryer. In practice, however, not
all bacteria particles are entrapped by this secondary filter 520B,
and moreover, further bacteria can enter the dryer 1 through gaps
in the housing 10, 11, and even when the hood 10 is open.
Therefore, the main filter 410B, on the main aperture 405, is used
to entrap any bacteria in the airflow that eludes entrapment by the
initial secondary filter 520B.
[0389] It is logical that the greater the thickness of filter
material that the airflow has to pass through, the greater the
likelihood that the airflow-borne bacteria will be entrapped.
However, it is not a viable solution simply to increase the
thickness of the main filter 410B found on the internal fan-casing
400. This is because the operation of the fan 401 requires a
certain input or throughput of air as part of the operational
parameters of the fan. If the main filter 410B were simply to be
thickened, then it could lead to a lower rate of air entering the
fan-casing, which would most likely lead to overheating and
degradation of the fan mechanism, and can even cause the fan motor
to catch fire.
[0390] Therefore, rather than simply increasing the thickness of
the main filter 410B, it is preferable to have two or more
entrapment filters in series, so as to effectively increase the
amount of filter material through which the airflow has to pass. In
other words, to have one or more secondary filters 520B through
which the airflow passes before coming to the main filter 410B.
[0391] Alternatively, in embodiments where there are a series of
entrapment filters, these can also be achieved by adding further
multiples of the entrapment filter components 410B, 410C. The
series would be achieved by adding to the stack of components. In
other words, it is better to have several entrapment filters in
series, rather than having one single entrapment filter of great
and equivalent thickness.
[0392] In the embodiment, the secondary filter 520B may also be
regarded as being in series with the main filter 410B because the
airflow passes through each of these filters, one after the other,
in sequence, or in series, as it were.
[0393] By way of background, the fan assembly 401 acts as an
air-pump that the sucks air from within the housing 10,11 into the
pump. To maintain the rate of airflow produced by the fan 401,
there must be a sufficient body of air for the fan to suck in. This
is why the housing 10, 11 is provided with a sizeable interior, so
that a sizeable body of air can be located proximate to the fan
assembly. This is also why the main aperture 405 and the main
filter assembly 410A, 410B, 410C are separated from its next
nearest entrance in the series, namely the initial secondary
aperture 520D and its filter assembly 520A, 520B, 520C, by a
substantial space in the housing that contains sufficient air to
satisfy the air intake requirements of the fan 401 assembly, in
terms of volume of air per unit time.
Benefit of Series Of Filters
[0394] In the embodiment, at least one secondary entrance 520D may
be located on an external surface of the housing 10, so as to be
accessible by the user from outside of the housing. FIG. 1A shows
the assembly 520A, 520B, 520C of the secondary filter in exploded
view, indicating that its components can be accessed and replaced
from outside of the housing 10.
[0395] In the embodiment of FIG. 1A and 1B, which has an inner main
filter 410B and an external secondary filter 520B, it is found that
the external filter 520B traps most of the dust and large
particulate. This leaves the main inner filter 410B to be used
mostly for entrapping the bacteria particles.
[0396] In experimental tests, it is found that, with the secondary
filter 520B alone, the dryer 1 is capable of achieving around a 79%
reduction in bacteria particles in the airflow that is emitted from
the dryer. It is believed that this loss of efficiency is because
some bacteria enters the housing 10,11 through the fine gaps
between the edge of the hood 10 and the baseplate 11.
[0397] However, with the combination of the main filter 410B
located at the final entrance 405 of the fan-housing, plus the
secondary filter 520B, experimental tests show the dryer 1 is
capable of reaching the goal of 100% removal of the bacteria
particles from the emitted airflow 200C.
[0398] In those modifications where the main filter is on the
surface of the hood 10, and where this is the only filter
arrangement, the preferred 100% bacteria reduction can be achieved,
preferably when all other gaps or entrances into the housing are
sealed in use. For instance, the gaps between the housing 10 and
the base plate 11 can be fitted with rubber gaskets, so that a seal
is created when the hood 10 is closed and pressed against the
baseplate 11, however, this modification is less effective when the
hood is opened to introduce bacteria into the apparatus. In other
words, in the embodiment, all gaps in the housing, that are not
intended by intent and design for the airflow path of the
apparatus, are sealed to such a level to prevent bacteria
entry.
[0399] For the avoidance of doubt, the airflow path of the
apparatus, which is by intent and design, is characterised by those
apertures that are provided with the intent to allow airflow
therethrough, and does not include unintentional gaps through which
air can enter unintentionally.
[0400] In other embodiments, the secondary filter holders 520A,
520C can also hold a wad of material that contains a fragrance. In
other embodiments, the secondary filter can carry both a
fragrance-carrier, as well as a filter material impregnated with
anti-bacteria, killing material.
Filter Replacement
[0401] In the present embodiment, the filter actually entraps the
bacteria particles and kills the entrapped particles. Consequently,
the filter can, over a period of time, become clogged with dead
bacteria particles. Hence, in the embodiment of FIG. 1A, it is
advisable for the filter or filters 410B, 520B to be replaced each
month.
[0402] In actual practice, it is possible that the person, who is
responsible for maintenance of the dryer, may forget to replace the
filters as frequently as required for optimum operating conditions.
If the filter is not replaced, such that it becomes clogged, this
may cause damage to the motor. For instance, the motor can overheat
because the clogged filter allows less air to reach the motor that
the motor requires to keep from overheating.
[0403] Hence, in modified embodiments in FIGS. 6A and 6B, the
bacteria-entrapment-filter-means includes a filter-replacement
mechanism that is able to automatically replace the filter
material, in use, with replacement filter material.
[0404] In the embodiment of FIG. 6A, the filter-replacement
mechanism includes a spool-motor 700. In FIG. 6A, the filter
material is in the form of a loop of sheet-like filter material
440B that travels around and around the spools 710 in a manner
similar to a conveyor-belt.
[0405] The sheet-like filter material 440B traverses across a
secondary aperture (not shown) in the hood 10 of FIG. 6A, so as to
act as a filter for that secondary aperture. Thus, over a period of
time, as the filter material 440B moves across the aperture, the
filter material in use is replaced with replacement filter material
periodically after a period of time.
[0406] In other embodiments, the sheet-like filter material 440B
may be adapted for use in the main filter assembly.
[0407] The movement of the spool-motor 700 is controlled by a
micro-processor control circuit which controls the timing and
motion of the spool-motor. The motor 700 can move the filter
material 440B either continuously or intermittently. For instance,
the motor can move the filter material once every month, so that
the filter material which covers the aperture in effectively
replaced each month. Alternatively, the motor 700 can move the
filter material 440B progressively with a constant, very slow
motion. This enables a greater amount of filter material to
participate in the filtering process. Assuming this filter material
440B is also replaced often, say, once a month, it would mean that
this form of cycling filter would have less likelihood of being
clogged.
[0408] The embodiment is provided with a guide to ensure that the
filter material is held taut against the aperture.
[0409] FIG. 6B shows another variation, in which the sheet-like
filter material 450B is formed like camera roll-film which rolls
from one spool to the next, eventually coming off the first spool
710A, at which point the air would pass unfiltered into the housing
10, 11. This means that the user, who is responsible for
maintenance, has to change the filter on time before the filter has
totally spooled onto the second spool 710B. The advantage of this
variation, however, is that the filter is unlikely to be clogged to
the degree that would lead to damage and overheating of the
fan-motor 430.
[0410] It is noted that FIGS. 6A and 6B have been drawn briefly,
only to show details of embodiments of a filter-replacement
mechanism, and for the sake of simplicity, other internal details
of the dryer, such as the fan-casing etc., have been omitted from
FIGS. 6A and 6B.
Safety Features
[0411] In the embodiment of FIG. 1A, the internal main filter
assembly 410A, 410B, 410C of FIGS. 1B and 3 can only be replaced by
opening up the housing to reveal the inner components within the
housing.
[0412] As a general comment, which pertains to hand dryers of this
art, the step of opening up the body or housing of a hand dryer, by
a user untrained as an electrician, can increase the risk of the
user being electrocuted.
[0413] In the embodiment of FIG. 1A, the dryer 1 has an electric
control circuit which supplies electrical power to the dryer 1. The
electrical control circuit is provided with a cut-off mechanism
that disables the supply of electrical power when the housing is
opened so as to minimise risk of the user being electrocuted when
opening the housing.
[0414] In FIG. 1B, the cut-off mechanism is in the form of a
resiliently-mounted switch 501 which enables the supply of
electrical power only when depressed.
[0415] FIG. 2A shows the embodiment of present embodiment with its
hood 10 in a closed state, while FIG. 2B shows the same with the
hood 10 in an open state. In this open state of FIG. 2B, the user
is able to access the internal components, and particularly is able
to change the internal main filter 410B.
[0416] To remove the risk of the user being electrocuted, the
interior of the hood 10 is provided with
cut-off-mechanism-activator or an actuator in the form of an
upstanding post 502. From comparing FIG. 2A with FIG. 2B, it is
evident that, when the hood is closed, the switch 501 is depressed
by the tip of the post 502. Whereas, then the hood is opened, the
tip of the post 502 lifts off the switch 501, thereby disabling the
supply of electrical power to the dryer 1.
[0417] The switch 501 is located and mounted on the baseplate 11.
The hood 10 of the housing is removably attachable to the baseplate
11. The post 502 is mounted on an interior surface of the hood.
[0418] In an alternative embodiment, the depressor (post) may be
mounted on the baseplate, while the switch may be mounted on an
interior surface of the hood.
[0419] The feature of the cut-off mechanism contributes, at least
in part, to achieving the goal of a sterilising hand-drying
apparatus that emits a stream of heated air that is preferably 100%
bacteria-free. This is because it allows for an internal filter
410B that can be replaced by a user, without risk of electrocution
when exposed to the internal components. Hence, it provides a safer
environment where a series of filters can be housed in the
dryer.
Installation Of The Dryer
[0420] In the embodiment of FIG. 1A, the base-plate 11 is fastened
to a wall, for example. The dryer 1 can be installed onto the wall
by attaching the housing 10 to the base-plate 11. This means that,
in practice, if the dryer 1 is defective, the user can disconnect
the hood 10 from the base-plate 11, and connect a defect-free
replacement hood 10.
[0421] The electrical cut-off switch 501 means that there is an
increased level of safety when the user opens up the hood 10, and
either installs or removes the hood and its included assembly of
components. The cut-off switch 501 ensures that the apparatus 1
cannot become electrically live until the hood is closed. A
commercial benefit of this feature is that the dryer 1 can
therefore be maintained by those who are not qualified
electricians. Generally there may be cost savings on the
maintenance of these drying apparatus, and there may also be
substantial savings when the apparatus is used in countries where
the absence of live electricity in the opened-dryer would avoid the
requirement of a qualified electrician to install the unit.
[0422] Also, in construction of large buildings, such as hotels or
hospitals, it is possible for the baseplate to be installed
initially by an electrician to connect the wiring to the mains
power, and then for another person to later on attach the hood 10
with its attached components e.g. 400, 430.
[0423] Another advantage of the ability to separate the assembly of
the hood 10 from the base plate 11 is that, rather then a repair
technician having to repair the dryer 1 on location, the user can
simply detach the hood assembly 10, with its components, and
replace it with a new hood. Then, the defective hood can be taken
away for repair. This means the repairman need not spend excessive
time at the location where the dryer is installed. Also, the user
experiences less down-time, and the user may replace the hood with
its components without assistance.
[0424] In the embodiment of FIG. 1A and 1B, the dryer 1 is
connected to an external source of electricity by a terminal block
500. The terminal block facilitates connection of the electric
control circuit of the dryer 1 to the external mains power
supply.
[0425] In FIG. 1B, the electrical control circuit of the dryer 1
has a plug 503 that is able to plug into the terminal block 500 in
order to connect to the mains power source.
Sensors
[0426] In FIGS. 1A and 1B, the dryer 1 is provided with a
sensor-means, in the form of a detector-sensor 600.
[0427] The detector-sensor 600 detects the presence of hands in the
vicinity of the projecting end-opening 14 on the front of the hood
10. When hands are detected, the detector-sensor 600 activates the
rotating fan 401 and the heating element 300. Thus, when a user
places his hands beneath the end-opening 14, the dryer 1
automatically activates and starts drying the user's hands.
[0428] In the embodiment, the detector-sensor 600 includes an
infra-red sensor.
Sanitising The Ambient Atmosphere
[0429] By way of review, the dryer of FIG. 1 has the capacity to
remove bacteria particles from the air that is sucked into the
housing 10, 11, and to expel it with all or substantially all of
the bacteria particles removed. Thus, if the fan 401 were to be
activated periodically, such a modified embodiments of the dryer 1
can function as atmospheric bacteria-removal apparatus. For
example, if the dryer 1 of the present embodiment were to be
activated every 30 minutes, or hour, or some other appropriate
interval, the air in the public toilet, for instance, can be
regularly purified of a substantial portion of its airborne
bacteria.
[0430] To achieve this, the modified apparatus 1 is provided with a
timer-control-circuit to regularly auto-activate the fan 401 for a
predetermined period of time.
[0431] Thus, periodic automatic activation of the apparatus 1
effectively sterilises part of the ambient atmosphere surrounding
the hand-drying apparatus. For example, the timer-control-circuit
may activate for 3 minutes every half hour.
[0432] In such a modified embodiment, the detector-sensor 600 can
also detect the absence of hands.
[0433] When the detector-sensor 600 detects that there is no
presence of hands in the vicinity of the end-opening 14, it is able
to auto-activate the dryer 1 to operate in the air-purifying mode
with heating the air flow.
[0434] This is the ensure that the dryer 1 does not blow cold or
unwarmed air onto hands that are placed below the end-opening 14.
Thus, the timer-control-circuit can activate the apparatus 1 at
regular intervals or intermittently to sterilise the ambient
atmosphere surrounding the apparatus 1.
[0435] This feature that enables the hand dryer to have the added
function of sterilising the ambient air is useful particularly in
seasons during the year when there are a greater occurrence of
airborne diseases. For instance, it is particularly useful during
influenza season.
[0436] This feature also enables the dryer to act as an
air-freshener, when a scented material is also held by the filter
holder. For instance, a pad of fragrance or perfumed substance can
be included between the filter holders 410A, 410C, 520A, 520C. When
used in conjunction with the timer control circuit, it means that
the ambient air of a washroom or public toilet environment can be
automatically and periodically infused at regular intervals with a
fragrance.
[0437] When using the apparatus 1 as a means of sanitising the
ambient environment air and/or adding fragrance to the ambient air,
it is preferred that the heating-element 300 not be activated,
otherwise for example the temperature of the washroom could
increase unnecessarily or to the point of discomfort for the
users.
[0438] Alternatively, in some embodiments, the heating-element 300
is can still activated during this automatic activation by the
timer control circuit. It is found that having the heater operating
during this automatic cycle does not excessively heat up the
ambient air.
[0439] Thus, some embodiments of the invention can function as a
combined air-fragrancer, sterilised hand dryer, and ambient air
sanitiser.
[0440] In a further embodiment, the timer-control-circuit is
provided with light-sensor-means 504, and can optionally be
constrained such that the timer-control-circuit only auto-activates
the apparatus, for the purposes of ambient air sanitising and/or
fragrancing, only when the light-sensor-means indicates that there
is ambient light. In other words, this function will not
auto-activate, for example, when the washroom or toilet is in total
darkness. This could apply to a case where a washroom is only used
during the daytime, and there is no need for the apparatus to be
operating continually through the night.
Further Alternatives
[0441] The embodiments have been advanced by way of example only,
and modifications are possible within the scope of the invention as
defined by the appended claims.
[0442] In other embodiments, the components of the fan casing 400
and the fan motor may be fastened to the base plate 11, rather than
inside the hood 10.
[0443] In other embodiments, the air stream 200C can be emitted
into a drying chamber, rather than directly to the ambient
environment surrounding the dryer 1.
[0444] The shape of the post 502 and the cut-off mechanism can be
varied to achieve the similar function. For instance, the cut-off
mechanism could be incorporated at the hinge 12. The embodiment is
not limited to a particular appearance of cut-off mechanism, as
long as the cut-off occurs when the hood is opened up.
[0445] The number of filters can be varied, particularly depending
on the power of the motor being used.
[0446] The style of motor or fan can be varied.
[0447] Any discussion of prior art in this specification is not to
be taken as an admission of the state of common general knowledge
of the skilled addressee.
[0448] The above specification contains description relating to a
number of aspects of the present invention.
OTHER INDUSTRIAL APPLICATIONS
[0449] The filter arrangement of the present invention can also be
used in other apparatus that draws in and expels an airflow, apart
from warm air hand dryers. Such other apparatus include, but are
not limited to: hair dryers, vacuum cleaners, fans, air
conditioners, refrigerators, clothing tumble dryers.
[0450] In the following exemplary embodiments of a hair dryer,
vacuum cleaner, fan and refrigerator, the above description of the
characteristics and benefits, and preferred features of the filter
arrangement of the hand dryer 1 are imported into the brief
descriptions of the hair dryers, vacuum cleaners, fans, air
conditioners, clothes dryer, refrigerator and other applicable
applications:
Example: Hair Dryer
[0451] FIG. 10A shows an embodiment of a filter arrangement used in
a hair dryer 2.
[0452] The airflow through the hair dryer 2 is represented by an
arrow 200A, 200C. Ambient air enters the hair dryer 2 (the arrow
200A), and is warmed, and then leaves the dryer (arrow 200C).
[0453] The intention, with the hair dryer 2, is the same as for the
hand dryer 1, namely that the stream of hot air 200C emanating from
the dryer should be free of bacteria.
[0454] The principles of arranging the filter arrangement in the
hair dryer 2 are somewhat similar to that of the hand dryer 1 in
terms of the sequence of filters in relation to the airflow,
however, the sequence of attachment to the base element is
reversed.
[0455] FIGS. 10A shows an exploded view of the main filter assembly
410A, 410B, 410C, 410D, 410E.
[0456] FIG. 10A shows the main filter assembly in relation to where
it fits into the main entrance 405 of the casing 400 of the hair
dryer. (Similar reference numerals are used as for earlier
embodiments merely to assist the reader to understand the
embodiment).
[0457] In FIG. 10A, the filter assembly includes a base element
410A that fits directly into the main entrance or main aperture 405
of the hair dryer.
[0458] The base element 410A is provided with several resilient
claws 408 that enable the base element to engage and lock with the
main aperture 405.
[0459] In the case of the hair dryer, the bacteria entrapment
filter 410B does not connect directly with the base element 410A.
Instead, the entrapment filter 410B must be the first in sequence
to receive the incoming airflow 200A.
[0460] The sequence of the filters is always described with respect
to the direction of the airflow 200A, 200C.
[0461] Accordingly, a filter holder 410C is used to carry a
bacteria entrapment filter material 410B. This is the first filter
that the airflow 200A encounters as it enters the hair dryer 2.
This entrapment filter 410B is coated with the anti-bacterial
sticky coating, and performs as described above.
[0462] Next, in sequence, the airflow encounters another filter
holder 410E that is used to carry the charcoal-infused filter 410D.
This charcoal filter 410D intercepts and removes from the airflow
200A any traces of the bacteria-killing material.
[0463] The filter holder 410E, for the charcoal filter, is the one
that engages with the base element 410A.
[0464] The base element 410A engages with the rear end of the hair
dryer 2.
[0465] Thus, the airflow which enters the main entrance 405 of the
hair dryer 2 is able to be 100% free of bacteria, and thus the warm
airflow that is expelled onto the user's hair is also 100% bacteria
free and, just as importantly, free of the toxic bacteria-killing
substance.
[0466] In another embodiment in FIG. 10B, a third filter can be
added in sequence to add a substance-effusing filter, in similar
manner as described above. A fragrance can be added to the airflow
which can add a scent to the hair that is being dried. The
fragrance filter would be positioned just between the base element
410A and the charcoal filter holder 410E. In other words, the
fragrance filter would be the last filter in sequence.
[0467] FIG. 10C shows another modification of the embodiment of
FIG. 10A, having a four-filter arrangement similar to that shown in
FIG. 8C.
[0468] In other embodiments, the filter arrangement 410A to 410E
can be housed inside the casing of the hair dryer 2 so as to be
inconspicuous to the user. The internal stack of filters also has
the bacteria-impermeable barrier, which confers benefits that have
been described in relation to the internal construction of the hand
dryer 1.
Example: Vacuum Cleaner
[0469] FIG. 11A shows an embodiment of a filter arrangement used in
a vacuum cleaner 3.
[0470] The airflow through the vacuum cleaner 3 is represented by
an arrow 200A, 200C. Ambient air enters the vacuum cleaner 3 (the
arrow 200A), is filtered for dust and large particulate, and then
leaves the vacuum cleaner (arrow 200C). It still, however, contains
bacteria, and hence the filter arrangement is used to remove the
bacteria and germs.
[0471] FIG. 11A shows an exploded view of the main filter assembly
410A, 410B, 410C, 410D, 410E.
[0472] FIG. 11A shows the main filter assembly in relation to where
it fits into the main outlet 405 of the rear of the casing 400 of
the vacuum cleaner. (Similar reference numerals are used as for
earlier embodiments merely to assist the reader to understand the
embodiment).
[0473] In FIG. 11A, the filter assembly includes a base element
410A that fits directly into the main entrance or main
outlet-aperture 405 at the rear of the vacuum cleaner.
[0474] The base element 410A is provided with several resilient
claws 408 that enable the base element to engage and lock with the
main outlet-aperture 405.
[0475] In the case of the vacuum cleaner, once again, the
entrapment filter 410B is the first in sequence to contact the
outgoing airflow 200C.
[0476] The sequence of the filters is always described with respect
to the direction of the airflow 200A, 200C.
[0477] In FIG. 11A, the filter assembly includes a base element
410A that fits directly into the main entrance or main
outlet-aperture 405 at the rear of the vacuum cleaner. The base
element 410A is provided with several resilient claws 408 that
enable the base element to engage and lock with the main
outlet-aperture 405.
[0478] The airflow 200C, emanating from the vacuum cleaner, first
encounters a bacteria entrapment filter 410B. The bacteria
entrapment filter 410B is supported and housed by a filter holder
410C which engages with the base element 410. This entrapment
filter 410B is coated with the anti-bacterial sticky coating, and
performs as described above.
[0479] The base element 410A and the filter holder 410C are
provided with corresponding bayonet mounting parts, to enable these
parts to fit with a bayonet-style engagement. In other embodiments,
other forms of engagements mechanisms can be used, such as
inter-fitting pins or press fit mounting.
[0480] Next, in sequence, the airflow encounters the
charcoal-infused filter 410D which is carried or housed by another
filter holder 410E. This charcoal filter 410D intercepts and
removes from the airflow 200A any traces of the bacteria-killing
material.
[0481] Thus, the airflow leaving the main outlet 405 of the vacuum
cleaner 3 is able to be 100% free of bacteria and, just as
importantly, free of the toxic bacteria-killing substance. Thus it
does not contribute to the bacterial contamination of the ambient
atmosphere.
[0482] In other embodiments, the filter arrangement 410A to 410E
can be housed inside the casing of the vacuum cleaner 3 so as to be
inconspicuous to the user. The internal stack of filters also has
the bacteria-impermeable barrier, which confers benefits that have
been described in relation to the internal construction of the hand
dryer 1.
[0483] The air that comes out of ordinary vacuum cleaner contain
germs that are sucked off the floor. Hence, the above filter
arrangement helps to remove the bacteria from the emanating airflow
from the vacuum cleaner.
[0484] FIG. 11B shows another modification of the embodiment of
FIG. 11A, having a four-filter arrangement similar to that shown in
FIG. 8C.
Example: Fan
[0485] FIG. 12A shows a front view of a fan 4 that uses an
embodiment of a filter arrangement. FIG. 12B shows a side view of
the fan.
[0486] The airflow through the fan 4 is represented by arrows 200A,
200C.
[0487] The rotatable fan blades 4A are housed in an enclosure
comprised of a cage made up of two opposed and facing
half-dome-like cages 4B-F, 4B-R (F=front, R=rear).
[0488] Ambient air (arrow 200A) enters the rear of the fan 4
through the rear half-dome cage 4B-R, and is expelled by the fan
through the front half-dome cage 4B-F (arrow 200C).
[0489] FIG. 12C shows an exploded side view of the main filter
assembly 410A, 410B, 410C, 410D, 410E, 410F, 410G. (Similar
reference numerals are used as for earlier embodiments merely to
assist the reader to understand the embodiment).
[0490] Attached to the outer surface of the rear dome-like cage
4B-R is a filter arrangement which is formed as a stack of nested
half-dome-like filter holders 410C, 410E, 410G. Each of these
filter holders carries within its dome a fibrous filter of the like
described above in relation to the filters used in the hand dryer
1.
[0491] In the embodiment, the function of the filter arrangement is
the cause the airflow 200C, emanating from the fan, to contain
substantially less bacteria than the airflow 200A which enters the
fan.
[0492] FIG. 12B shows a side view of the main filter assembly with
all the filter holders 410C, 410E, 410G attached to each other in
sequence. The filter holders 410C, 410E, 410G are more clearly seen
in the exploded view of FIG. 12C.
[0493] The filter holders are provided with attachment means that
enables them to be attached to the back of the rear dome-like cage
4B-R. The actual attachment means is not illustrated here, and can
be implemented in numerous forms.
[0494] As the airflow 200A is drawn towards the fan 4, it initially
encounters a first filter holder 410C which contains, held on its
inner curved surface, a bacteria entrapment filter material 410B,
of the kind and function described above in relation to the hand
dryer 1.
[0495] Next, where applicable or required, the airflow 200A
encounters a second filter holder 410E which contains, held on its
inner curved surface, a charcoal-particle infused filter 410D, of
the kind and function described above in relation to the hand dryer
1.
[0496] Preferably, the airflow 200A encounters a third filter
holder 410F which contains, held on its inner curved surface, an
effusing filter 410F which effuses an emittable-substance, from the
fibres of the filter 410F, into the airflow, of the kind and
function described above in relation to the hand dryer 1.
[0497] Thus, the airflow which enters the expelled from the fan is
able to have substantially less bacteria than the level of the
ambient air, and, just as importantly, is free of the toxic
bacteria-killing substance that is used to kill the bacteria in the
entrapment filter 410B.
[0498] In other embodiments, the filter arrangement 410A to 410G
can be housed inside a casing for the fan 4 so as to be
inconspicuous to the user.
[0499] The filter holders 410C, 410E, 410G are formed as
semi-circular dome-like cages that have a slit along a radius of
the dome that can be spread apart temporarily to enable the filter
holders to fit over the supporting stand or frame 4C of the
fan.
[0500] The filter holders each also have a centrally located hole
to accommodate the frame 4C of the frame.
[0501] In the embodiment, the actual configuration of the fan is
not part of the invention, since embodiments of the filter
arrangements, of the present invention, can be adapted for use with
a wide variety of fans.
[0502] FIGS. 12D and 12E show a further embodiment of a filter
arrangement used with a fan, having a four-filter arrangement that
has a similar function to that of the embodiment in FIG. 8C.
Examples: Air Conditioner & Garment Dryers
[0503] Embodiments of the filter arrangement can also be
incorporated in air conditioners and garment or clothes dryers. In
the case of garment dryers, the filter arrangement is on the air
inlet to ensure that the clothes are not subjected to
bacteria-laden air
[0504] In the case of hair dryers and garment dryers, the filtering
occurs as the airflow enters the device.
[0505] In the case of the hand dryer and vacuum cleaner, the
filtering occurs as the air flow leaves the device.
[0506] Embodiments of the filter arrangement can also incorporated
in refrigerators to ensure that the air that enters the interior of
the refrigerator is free of bacteria.
[0507] Three and four filter arrangements can also be used in these
embodiments.
Examples: Clothes Dryer
[0508] FIG. 13 shows a simple schematic diagram of a clothes dryer
5. The actual mechanics of the machine are known to a skilled
address in the field of clothes dryers, and are not described in
detail here.
[0509] The clothes dryer 5 contains an enclosure SA within the
machine that receives hot air to dry the clothes.
[0510] An airflow 200A enters the machine, and passes first through
a bacteria entrapment filter 410B, of the kind and function
described above in relation to the hand dryer 1.
[0511] Next, in sequence, the airflow 200A passes through a
charcoal-particle infused filter 410D, of the kind and function
described above in relation to the hand dryer 1.
[0512] Thus, the airflow which enters the enclosure 5A is able to
have substantially less bacteria than the level of the ambient air,
and, just as importantly, is free of the toxic bacteria-killing
substance that is used to kill the bacteria in the entrapment
filter 410B.
[0513] Three and four filter arrangements can also be used in these
embodiments used in clothes dryers.
Examples: Refrigerator
[0514] FIG. 14 shows a simple schematic diagram of a refrigerator
6. The actual mechanics of the refrigerator are known to a skilled
address in the field of refrigeration manufacture, and are not
described in detail here.
[0515] The refrigerator 6 contains an enclosure 6A which receives
chilled refrigerated air.
[0516] An airflow 200A enters the machine, and passes first through
a bacteria entrapment filter 410B, of the kind and function
described above in relation to the hand dryer 1.
[0517] Next, in sequence, the airflow 200A passes through a
charcoal-particle infused filter 410D, of the kind and function
described above in relation to the hand dryer 1.
[0518] Thus, the airflow which enters the enclosure 6A is able to
have substantially less bacteria than the level of the ambient air,
and, just as importantly, is free of the toxic bacteria-killing
substance that is used to kill the bacteria in the entrapment
filter 410B.
[0519] Three and four filter arrangements can also be used in these
embodiments used in refrigerators.
Chemical Release Agent
[0520] In the embodiment of the hand dryer 1 and other embodiments
of airflow apparatus described above, the airflow is able to be
intermittent. In other words, there can be lengthy periods of time
where there is no operational airflow generated through the
apparatus.
[0521] Reference is made to the exemplary embodiments of FIGS. 8A
and 8C, and also FIGS. 10B, 10C, 11B, 12C, 12D, and the like. In
these embodiments, where there are one or more effusing filters
410F, 410FF, there is an active substance on the filter fibres that
is capable of becoming airborne. For instance, in the embodiments,
the active substance could be a fragrance, perfume, or even a mild
non-toxic anti-bacteria substance.
[0522] In the air-flow activated composition, the active substance,
is capable of becoming airborne at least for a useful period of
time. For instance, the active substance can evaporate into a
vapour, or effuse into the air as a mist.
[0523] In a modified embodiment, the active substance is able to be
combined with a release agent that restrains the active substance
from becoming airborne at normal room temperature and pressure,
however, upon exposure of the composition to the airflow, the
release agent will release the active ingredient into the air
stream.
[0524] An advantage of using the active substance, in combination
with such a release agent, is that it avoids or minimises passive
effusion of the active substance into the atmosphere when there is
no airflow operating through the apparatus. Thus, the active
substance, found on the filter, can potentially last longer,
compared to a case where the active substance were to be
continually and gradually effusing into the air, even when there is
no operational airflow.
[0525] The active substance may be any substance or combination of
substances that may usefully be made airborne for the purposes of
the invention. For example, the active substance may be a
fragrance, deodorant or biocide. The biocide may be a bactericide
or insecticide. Preferably, the active agent is a biocide such as
n-alkyl dimethyl benzyl ammonium saccharinate, quaternary ammonium
salts (such as chlorides), Triclosan, o-benzyl chlorophenol,
2-phenylphenol and/or N-alkyl N-Ethyl morpholinium sulphates.
[0526] Preferably, the active substance is volatile within the
normal range of ambient temperatures and pressures, but this is not
essential to the invention as long as the active substance is able
to remain airborne for sufficient time to have its useful
effect.
[0527] The active substance may be dissolved or suspended in a
carrier. The carrier may be formulated to enhance the volatisation
of the active substance, once released into the surrounds. The
carrier may be formulated to physically and/or chemically stabilise
the active substance against deterioration over time. For example,
the carrier may include a UV stabiliser to reduce deterioration of
the active substance where the active substance may be exposed to
sunlight during transport or storage.
[0528] The carrier may be a solvent that is volatile at room
temperature, preferably non-toxic to mammals, such as water,
linseed oil, suitable organic solvents, alcohol or a mixture
thereof. Solvent mixtures may be advantageously used, for example,
where the active substance comprises two or substances having
different solubilisation or dissolution properties. Preferably,
where the active substance and/or the carrier include a volatile
component, the release agent will encapsulate the active substance
and/or the carrier.
[0529] The release agent includes any substance or combination of
substances that:
[0530] (1) is/are adapted to contain or retard the active substance
against becoming airborne such as by volatisation; and
[0531] (2) remain stable at normal room temperature and pressure in
still air.
[0532] The release agent will therefore vary in formulation and/or
preparation according to the properties of the active substance
used in a particular application. The release agent will therefore
be compatible with the active substance and different formulations
of release agent will be applicable depending on the active
substance. The active substance may be impregnated, embedded or
encapsulated in, or physically or chemically bonded to the active
substance. In a particularly preferred formulation according to the
invention, the active agent includes a volatile biocide
microencapsulated in the release agent. In another preferred form,
the active substance is a fragrance.
[0533] The release agent may be a solvent, gel, paste or slurry
with low or virtually no volatibility at room temperature and
pressure, the solvent, paste or gel able to be volatised only by
the application of air flow and/or warmed air. For example, the
active substance may be stably impregnated, dissolved or mixed in
the release agent at room temperature and pressure, the active
substance at least substantially retarded against volatisation and
preferably trapped in the release agent. Upon exposure to flowing
air, optionally heated, the release agent may become volatile
and/or unstable to release the active substance to the passing air
stream.
[0534] Where the release agent includes a solvent, this may be
viscous and non-volatile at room temperature and pressure. Examples
of suitable solvents include vegetable oils with suitably heavy
fractions such as cooking oils, lanolin, and fatty acids such as
stearic acid.
[0535] Where the release agent includes a gel, this may be a
polymeric material. The polymeric material may be a homopolymer or
copolymer. The polymeric material may be cross linked.
[0536] Preferably, the release agent is in the form of small
capsules or microcapsules. The microcapsules typically have a
diameter smaller than 500 .mu.m, and preferably are in the range
5-200 .mu.m. A particularly preferred type of capsule is a wall or
shell type capsule which has a generally spherical, hollow shell of
material insoluble to the active substance. The material is
normally a plastic material. The plastic material may be a polymer
or copolymer, optionally crosslinked and optionally including
suitable additives known in the art to achieve desired properties.
The plastic material may be a resin. The plastic material may be an
amino resin such as the condensation products of urea and of
melamine with formaldehyde.
[0537] There are various methods of making such shell capsules
including in situ polycondensation used to produce aminoplast resin
capsules from urea-formaldehyde or melamine-formaldehyde polymers.
The process may involve forming a dispersion or emulsion of the
active substance, for example in an aqueous solution of
urea-formaldehyde or melamine-formaldehyde precondensate under
agitative conditions to obtain capsules in a preselected size
range. Conditions can be adjusted to cause condensation of the
precondensate by acid catalysis resulting in the condensate
separating from solution and surrounding the dispersed active
substance to produce microcapsules.
[0538] The microcapsules show excellent active substance retention
over long periods because the capsule prevents evaporation or other
loss of the active substance until the integrity of the capsule
walls is disrupted to release active substance or the walls are
otherwise ruptured. In its most preferred form, the present
invention is concerned with microcapsules having good storage
stability properties in static air, but having polymer walls
adapted to lose sufficient structural integrity on exposure to
rapidly flowing air.
[0539] The microencapsules are optionally formed by a coacervation
process in which a carrier in the form of an oil reservoir is
surrounded by a very thin polymeric membrane which is generally
mechanically very unstable, but hydrophobic and resistant to humid
conditions such as may be found in a public rest room. This
property is exploited in use in the active substance delivery
application, wherein the delivery is initiated by mechanical force,
such as by the application of a stream of air to disturb the
integrity of the polymeric membrane and to release the active
substance.
[0540] Where the release agent includes a paste or slurry, this may
include a synthetic or natural adhesive such as gum Arabic or a
synthetic polymer adhesive to act as a binding agent.
[0541] The release agent may be a micro porous encapsulation
product. The release agent may be a melamine polymer shell. The
melamine polymer shell is preferably comprised of microencapsulates
adapted to retain the active agent. The polymer shell may be
impervious and therefore effective to contain a volatile active
agent, such as a fragrance or biocide. The microencapsulates may
contain both fragrances and biocides. The fragrances may be
chemically unreactive and therefore storable in the same
microcapsule without deterioration. Alternatively some of the
microencapsulates may contain fragrance, and others, biocide. The
mixture of microencapsulates may be stored in the same device, such
as a filter cartridge. The microcapsules may vary dimensionally,
such as in the range 3-500 .mu.m, preferably 3-200 .mu.m and still
more preferably 5-100 .mu.m.
[0542] The release agent may be suitably formulated for bonding or
otherwise adhering to a substrate. The substrate may be a porous
panel such as wire or plastic mesh. The panel may be of sufficient
gauge to permit the flow of air there through. The release agent
may be sufficiently tacky or sticky to adhere to the surface of the
panel and to itself.
[0543] The substrate may be a filter medium. The filter medium may
be filter fibres. The filter media may be natural or synthetic
material, depending on the application and the filtration
properties required. The filter media may include cellulosic based
fibre, such as cotton weave, or a synthetic material, such as
polyester, or a combination thereof. The substrate may be
additionally impregnated or coated with other useful substances
such as carbon to act as a deodoriser and/or absorbent.
[0544] The release agent and active substance may together be
applied as a mass, optionally layered, to the substrate by
spraying, brushing or rolling on. As air flow is applied to the
substrate, the surface layer of the composition is depleted,
thereby exposing previously unexposed surface to the surrounding
environment. The composition mass may advantageously present new
surface material through multiple applications of flowing air over
time.
[0545] Preferably, the active substance is contained in the release
agent in the form of polymer microcapsules. The microencapsulates
may be sprayed or otherwise applied onto the substrate surface,
such as a filter, for installation in a cartridge. The
microcapsules may be applied by spraying an emulsion onto the
substrate. A suitable microencapsulate system may be obtained from
Reed Pacific Pty Ltd under the product name "Potenza", optionally
with suitable additives to provide the air-flow release
capability.
[0546] The composition may be presented in the form of an enclosed
cartridge for the preservation of the composition and easily
substitution for spent, like components. The cartridge may include
a sealed container in which is housed the composition for storage.
The cartridge is preferably vacuum sealed once the composition is
delivered to the cartridge. The cartridge may be made from any
suitable material resistant to the composition components. Suitable
materials may include APET, PETG, polypropylene and
polyacrylonitrile for their clarity, thermoformability and general
chemical resistance. Other materials having less clarity may
include polyethylene, and nylon. Other materials may be selected
for their strength and chemical resistance, such as aluminium or
stainless steel. Of course, the skilled person will select a
suitable material or combination of materials according to the
composition formulation.
[0547] The container may include a seal. The seal may be activated
to expose the contents of the cartridge to the surrounding
environment. The seal may be deflectable, removable or penetrable.
The seal may be adapted to be activated when the cartridge is
placed in active use to expose its contents. The seal may be a
membrane or film. The membrane or film may be made from metal foil
or soft plastic such as polyethylene.
[0548] The composition may be applied to the substrate in the form
of panels arranged in parallel or in series, depending on the
application, with respect to the anticipated direction of air flow
in use. Alternatively, the substrate may be in the form of columns,
nodules or amorphous fibre, whereby new surface of the composition
is exposed to the surrounding air as the previous composition
surface is progressively depleted.
[0549] Normal room temperature, humidity and pressure will vary
depending on a number of factors including location and season.
Generally, high altitude locations far from the equator will be
characterised by cooler temperatures and lower air pressures,
whereas equatorial regions will be characterised by warmer ambient
temperatures and higher humidity and pressure. The skilled person
will appreciate that such factors need to be considered in
determining the composition formulation.
EXAMPLE 1
[0550] A lemon-scented fragrance was encapsulated in micro melamine
polymer shells ranging between 5-100 .mu.m in size. The polymer
shells were impervious to the encapsulated fragrance to preserve
the fragrance until the release trigger was activated. (However,
the polymer shells are sufficiently thin whereby their structural
integrity is easily disrupted by mechanical agitation; such as by
the application of a blast of moving air over the surface of the
polymer shells.) The microencapsulates were sprayed onto a filter
cartridge and the cartridge was vacuum sealed. The cartridge was
then opened and installed in a washroom hand dryer. When the hand
dryer was on, a passage of warm air (about 50.degree. C.) passed
through the cartridge. The flow of air structurally disrupted the
microencapsulates polymer shell walls and volatile fragrance was
released. The cartridge was left in the hand dryer and anecdotally
tested for fragrance effectiveness many times per day. A good
spread of fragrance release was observed over a thirty five day
period. Suitable encapsulate product may be purchased from Canpoint
International Pty Limited of Lidcombe, NSW, Australia. Independent
testing by a UK laboratory showed that the application of the
composition to the filter medium resulted in at least a 79%
reduction in the total number of live airborne fungal spores in air
having passed through the air dryer containing an active
cartridge.
EXAMPLE 2
[0551] A suitable composition formulation in the form of a stable
perfumed gel is described in U.S. Pat. No. 5,419,879 to Vlahakis et
al. U.S. Pat. No. 5,419,879 describes the manufacture of a perfumed
stable gel comprised of a combination of chemical components. The
perfumed stable gel has a melting point temperature range of from
about 125 DEG F. to about 150 DEG F. The preferred melting point
temperature of the gel is about 140 DEG F. The perfumed stable gel
has a perfume content of from about 70.0% to about 85.0% by weight
of the composition. The preferred perfume content is about 75.0% to
about 80.0% by weight of the composition. The more preferred
perfume content is about 75.0% by weight of the composition. The
stable nature of the perfumed gel of this prior art disclosure
means that the gel can be maintained as a solid, homogeneous,
uniform mixture. The perfumed stable gel will not liquefy or form a
slurry, but will remain as a solid, under the above temperature
conditions and having the above perfume content.
[0552] Vlahakis' perfumed stable gel composition includes water in
an amount of from about 2.0% to about 10.0% by weight of the
composition. Preferably, the water is at its boiling point when
initially mixed with an odourless glycol, and preferably the water
is in an amount of about 5.0% by weight of the composition.
[0553] The perfumed stable gel composition also includes a soap in
an amount of from about 5.0% to about 15.0% by weight of the
composition. The preferred soap is sodium stearate having a carbon
content in the range of C12-C20 and having a melting point of about
158 DEG F. or higher. Preferably, the soap is in an amount of about
7.5% by weight of the composition in the formulations for the
cherry, jasmine, baby powder, and spice deodorant gels. Preferably,
the soap is in an amount of about 9.0% by weight of the composition
in the formulations for the green apple, lemon, bubble gum,
spearmint, and gardenia deodorant gels. The increased amount of
soap in these latter formulations increases the melting point and
aids in solubilizing the perfumes.
[0554] Vlahakis' perfumed stable gel composition also includes a
non-ionic surfactant to increase the melting point of the
composition and aid in initially maintaining the composition
product in solution and later stabilizing the composition product
as a solid. Preferably, the non-ionic surfactant contains a
sufficient amount of ethylene oxide to provide a melting point
temperature in the range of from about 100 DEG F. to about 150 DEG
F. The non-ionic surfactant is preferably in an amount of from
about 2.0% to about 15.0% by weight of the composition. More
preferably, the non-ionic surfactant is in an amount of about 3.75%
by weight of the composition. The preferred non-ionic surfactants
that are used include nonylphenols, polyethylene glycols, or a
mixture thereof. The nonylphenols may include Nonoxynol 100, with
100 mols of ethylene oxide in the product, Iconol NP-100, and
nonylphenols of 80 mols up to 150 mols. The polyethylene glycols
may include polyethylene glycol 8000 and BASF's Pluracol line.
Other non-ionic surfactants that can be used include non-ionics
similar to BASF's Tetronic and Tetronic R line. However, this
latter group of non-ionic surfactants is generally more expensive
to use than the former groups.
[0555] The perfumed stable gel composition also includes a
preservative in an amount of from about 0.1% to about 0.3% by
weight of the composition. The preservative helps to inhibit the
growth of mould or fungus on the surface of the perfumed stable
gel. The preferred preservative used in the present invention is
Glydant (chemically known as DMDM Hydantoin (55% solution)(C7 H12
N2 O4)--Chemical Abstract No. is 6440-58-0). Preferably, the
preservative is in an amount of about 0.25% by weight of the
composition.
[0556] Vlahakis' perfumed stable gel composition may also include a
perfume component. It has been found that an effective perfume
content for Viahakis' composition is in an amount of from about
70.0% to about 85.0% by weight of the composition. For the purposes
of the present invention, it is preferred that the amount of
perfume be reduced to less than about 50% by weight of the
composition to afford greater stability with the other components
increased proportionally to make up the balance of the percentage
weight of the composition. The perfume agent enhances the odour
characteristics of the product. Specific examples of suitable
perfume agents include lemon, bubble gum, cherry, spearmint, green
apple, baby powder, gardenia, jasmine, herbal, spice, and others.
The primary scents used are obtained from the fruity and floral
scent groups. However, it is possible to produce any number of
different scents depending on the type of scent desired.
[0557] Vlahakis' perfumed stable gel composition also includes an
odourless glycol. The amount of odourless glycol used in the
chemical composition should be sufficient to aid in solubilizing
the perfume component. The addition of an odourless glycol aids in
the stability of the evaporation rate of the composition and aids
in increasing the melting point of the composition. Preferably, the
amount of odourless glycol used is in an amount of from about 0.1%
to about 12.0% by weight of the composition. The preferred amount
of odourless glycol is about 8.75% by weight of the composition.
The preferred odourless glycols used in the composition include
propylene glycol, glycerol, hexylene glycol, or a mixture of two or
more thereof.
[0558] Vlahakis' perfumed stable gel composition may also include
inert filler materials. The amount of filler material used in the
composition is from 0% to about 4.0% by weight of the composition.
Preferably, the amount of filler material used is about 0.5% by
weight of the composition. The filler material may be selected from
the group including diatomaceous earth, clay, dirt, silica and
sand. The addition of these filler materials to the composition is
optional. However, the filler material helps to control the
evaporation rate of the perfume component.
[0559] Vlahakis' perfumed stable gel composition may also include
ethanol or odourless mineral spirits. The amount of ethanol or
odourless mineral spirits used is from 0% to about 5.0% by weight
of the composition. Preferably, the amount of ethanol or odourless
mineral spirits used is about 3.0% by weight of the composition.
The ethanol and odourless mineral spirits aid in solubilizing some
of the perfumes and in lowering the costs of manufacturing some of
the more expensive perfumes (i.e., green apple) without affecting
the performance of the gels. Preferably, the mineral spirits are
comprised of aliphatic hydrocarbons.
[0560] The manufacture of Vlahakis' perfumed stable gel involves
the mixing of: (1) an oil phase and (2) a water phase. The oil
phase includes the non-ionic surfactant and the desired perfume.
First, the non-ionic surfactant is heated to a temperature in the
range of from about 120 DEG F. to about 150 DEG F. It is heated in
a 55 gallon jacketed stainless steel mixing vessel. Heating bands
surrounding the mixing vessel act to heat and liquefy the non-ionic
surfactant. The non-ionic surfactant is heated in this manner for
about 24 to 48 hours, depending on the size of the batch and the
heating temperatures used.
[0561] After the non-ionic surfactant has been sufficiently heated
and liquefied, it is transferred to a smaller open-top 55 gallon
jacketed stainless steel mixing vessel. This mixing vessel also has
heating bands surrounding it which act to heat the non-ionic
surfactant and the perfume, which is added at this step in a
pre-measured amount. The two components are thoroughly mixed in the
mixing vessel with an electric mixer that has an attached agitator
working at approximately 750 rpm. The perfume is mixed with the
non-ionic surfactant for approximately 10 minutes at a temperature
in the range of about 120 DEG F. to about 150 DEG F.
[0562] The second phase involved in forming the perfumed stable gel
is the water phase. To manufacture the water phase, a pre-measured
amount of the odourless glycol is added to boiling hot water. The
glycol and water are mixed together in an open-top 55 gallon
jacketed stainless steel mixing vessel. The two components are
thoroughly mixed in the mixing vessel with an electric mixer that
has an attached agitator working at approximately 750 rpm. The
odourless glycol is mixed into the hot water for approximately 5
minutes at a temperature of about 158 DEG F. Next, the soap is
added in a pre-measured amount to the glycol/water mixture. The
soap is thoroughly mixed into the glycol/water mixture in the
mixing vessel until the soap is dissolved and there are no clumps
remaining. The soap is mixed with the odourless glycol and water
for approximately 15 minutes to 30 minutes at a temperature of
about 158 DEG F.
[0563] Next, the mixture of the water, the odourless glycol, and
soap, i.e., the water phase, is added to the non-ionic surfactant
and perfume, i.e., the oil phase. All of these components are
thoroughly blended at a temperature of over 140 DEG F. in the
mixing vessel with an electric mixer that has an attached agitator
working at approximately 750 rpm. The preservative is added at this
stage of the mixing. All of these components are then thoroughly
mixed for approximately 15 minutes.
[0564] Finally, an optional filler material can be added to the
mixture by spooning with a ladle a desired amount of the filler
material into the mixture. The mixture is stirred thoroughly until
the desired consistency is reached.
[0565] Once it is determined that the composition is thoroughly
blended and while it is still in the molten state, the composition
is spooned with a ladle out of the mixing vessel and into the
individual deodorant containers.
[0566] Lastly, the containers holding the composition are cooled by
placing the dispensers on a conveyer belt and blowing cold air upon
those dispensers. The cold air is passed through a tunnel fed by an
air conditioning unit. During the containers' 3 to 5 minutes in the
tunnel, the gel composition solidifies in the dispenser assembly,
thus securing the completed perfumed stable gel in the disposable
deodorant container. The amount of composition prepared at one time
is limited to the amount that is to be filled in the dispensers on
a particular day. Typically, this amount can vary between 200
pounds to 400 pounds per day.
EXAMPLE 3
[0567] In prior art GB Patent Application No. 1,432,163 (CIBA GEIGY
AG) there is described a slow release formulation which is suitable
for use in the present invention, release of active substance being
negligible in still air at room temperature and pressure, but
accelerated when subject to an air stream at elevated temperature,
such as may be provided in or adjacent an electric fan hand
dryer.
[0568] Particularly good long lasting deodorising is obtained using
the following air conditioning preparations according to the
formulation in GB 1,432,163:
[0569] 1) Gelling agent: bentonite derivatives or aluminium
soaps
[0570] Deodorant: dimethylfumarate or diethylfumarate; and [0571]
Reodorant: diphenylmethane, diphenylether, bornylacetate or
mixtures thereof, wherein with bornylacetate and linalool
deodorising action is still evident, even after 90 days.
[0572] 2) Gelling agent: polymer resins
[0573] Deodorant: dimethylfumarate or diethylfumarate; [0574]
Reodorant: diphenylether, bornylacetate.
[0575] 3) Gelling agent: bentonite derivatives, aluminium soaps or
polymer resins
[0576] Deodorant: citral or several aldehydes which are free of
aromatic nuclei; [0577] Reodorant: diphenylmethane, wherein using
bentonite derivatives as gelling agents, deodorising action is
still evident even after 90 days.
[0578] 4) Gelling agent: bentonite derivates
[0579] Deodorant: phenylacetaldehyde and similar aldehydes
containing at least one aromatic nucleus; [0580] Reodorant:
diphenylmethane, diphenylether, bornylacetate, wherein deodorising
action is still evident even after using the preparation for 90
days.
[0581] 5) Gelling agent: aluminium distearate
[0582] Deodorant: mixture of citral and dimethyl and/or diethyl
fumarate in a weight ratio of 1:5 to 5:1; [0583] Reodorant:
diphenylether or bornylacetate, wherein deodorising is still
evident even after use of this preparation for 90 days.
[0584] The composition is preferably prepared by:
[0585] 1) heating the total quantity of gelling agent such as
aluminium soap and liquid paraffin regularly and with continuous
stirring until one obtains a homogenous gelled mass of temperature
between 70 and 150.degree. C.;
[0586] 2) cooling the resultant gel with continued stirring to
90.degree. C.; adding the total quantity of deodorant and
reodorant;
[0587] 3) adding the total quantity of deodorant and reodorant; and
finally
[0588] 4) casting the resulting fluid gel into moulds at about
80.degree. C. or working it to a granulate in a granulation
apparatus.
[0589] On cooling the preparations according to this prior art
composition example, there is obtained a solid preparation. This
preparation can easily be removed from moulds and can then be
packed in a casing such as a modular cartridge installable in a
blower hand dryer, the cartridge being impermeable for the
deodorant and reodorant components in storage, this cartridge being
opened or activated by the user to expose the composition.
[0590] The embodiments have been advanced by way of example only,
and modifications are possible within the scope of the invention as
defined by the appended claims.
* * * * *