U.S. patent application number 12/531250 was filed with the patent office on 2010-08-19 for airflow system and apparatus and method for airflow system.
Invention is credited to Rudolf Hanselmann, Richard Rubin.
Application Number | 20100209080 12/531250 |
Document ID | / |
Family ID | 39758908 |
Filed Date | 2010-08-19 |
United States Patent
Application |
20100209080 |
Kind Code |
A1 |
Rubin; Richard ; et
al. |
August 19, 2010 |
AIRFLOW SYSTEM AND APPARATUS AND METHOD FOR AIRFLOW SYSTEM
Abstract
An airflow system enhances airflow in a hand-drying apparatus
which expels a stream of sterilised, hot air for drying of hands.
Inside the apparatus, the airflow is decelerated by one or more
filters. Therefore, the system is provided with an airflow-pathway
that is progressively smaller along its pathway in respect of
flowthrough cross-section. The airflow is enhanced by flowing
initially through a larger part of the airflow-pathway, and
subsequently through a smaller part of the airflow-pathway after
which the airflow exits the apparatus. To enhance the airflow, a
universal commutator motor is used to drive an appliance that
provides air movement. The motor comprises magnetic field
generating means, a rotating armature adapted for rotational motion
in operative association with the magnetic field. A ratio of
magnetic field strength at the armature to the magnetic field
strength within the magnetic field is less than about 1 to 1.
Inventors: |
Rubin; Richard; (Victoria,
AU) ; Hanselmann; Rudolf; (Smithfield New South
Wales, AU) |
Correspondence
Address: |
STITES & HARBISON PLLC
1199 NORTH FAIRFAX STREET, SUITE 900
ALEXANDRIA
VA
22314
US
|
Family ID: |
39758908 |
Appl. No.: |
12/531250 |
Filed: |
March 12, 2008 |
PCT Filed: |
March 12, 2008 |
PCT NO: |
PCT/AU08/00338 |
371 Date: |
April 6, 2010 |
Current U.S.
Class: |
392/380 |
Current CPC
Class: |
H02K 23/40 20130101;
H02K 13/006 20130101; A47K 10/48 20130101 |
Class at
Publication: |
392/380 |
International
Class: |
A47K 10/48 20060101
A47K010/48 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 12, 2007 |
AU |
2007201038 |
Mar 12, 2007 |
AU |
2007201120 |
Mar 12, 2007 |
AU |
2007901255 |
Claims
1. An airflow system adapted to enhance airflow in a hand-drying
apparatus which expels a stream of substantially sterilised, hot
air that is heated by a heating-means for drying of hands, where
the airflow inside the apparatus is decelerated by one or more
filters through which the airflow passes, wherein the system,
downstream of the heating-means, is provided with an
airflow-pathway that is progressively smaller along its pathway in
respect of flowthrough cross-section, such that, in use, the
airflow is enhanced by flowing initially through a larger part of
the airflow-pathway, and subsequently through a smaller part of the
airflow-pathway after which the airflow exits the apparatus.
2. A system of claim 1 wherein the airflow-pathway includes at
least a part that has a degree of taper.
3. A system of claim 2 wherein the degree of taper is able to be
selectively varied by the user.
4. A system of claim 1 wherein the degree of taper of the
airflow-pathway is able to be selectively varied by the user
substituting a replacement airflow-pathway device of different size
preferably selected from a range of passageways of differing
degrees of taper.
5. A system of claim 2 wherein the airflow-pathway includes parts
that are not tapered.
6. A system of claim 1 wherein the hand-drying apparatus, in which
the system is adapted to be used, comprises: a completely sealed
apparatus-housing that includes therein a fan-casing containing a
fan.
7. A system of claim 6 wherein all airflow enters the
apparatus-housing through initial main-inlet-means on the
apparatus-housing, and all airflow subsequently enters the
fan-casing through final main-inlet-means on the fan-casing,
wherein the initial main-inlet-means is larger than the final
main-inlet-means such that, in use, the airflow is enhanced by
flowing initially through the larger initial main-inlet-means, and
subsequently through the smaller final main-inlet-means.
8. A system of claim 7 where the larger initial main-inlet-means
and the smaller final main-inlet-means have flowthrough
cross-sections which have a ratio of around 1.38 relative to one
another.
9. A system of claim 6 wherein the fan is a dual-fan comprising two
fan-halves each of which is adapted to draw in airflow into the
fan-casing.
10. A system of claim 1 wherein the airflow inside the apparatus is
decelerated by a plurality of filters
11. An airflow system of claim 1 in which the airflow through the
system is driven by a fan apparatus that is activated by a
universal commutator motor.
12. A sterilising hand-drying apparatus which includes an improved
airflow system of claim 1.
13. A method of enhancing airflow through a hand-drying apparatus
that expels a stream of substantially sterilised, hot air that is
heated by a heating-means for drying of hands, where the airflow
inside the apparatus is decelerated by one or more filters through
which the airflow passes, wherein the method includes providing the
apparatus with an airflow system which, downstream of the
heating-means, includes an airflow-pathway that is progressively
smaller along its pathway in respect of flowthrough cross-section,
and, in use, enhancing the airflow by causing the airflow to flow
initially through a larger part of the airflow-pathway, and
subsequently through a smaller part of the airflow-pathway after
which the airflow exits the apparatus.
14. (canceled)
15. A hand-drying apparatus airflow system adapted to enhance
airflow in an apparatus that expels a stream of substantially
sterilised, hot air that is heated by a heating-means for drying of
hands, where the airflow inside the apparatus is decelerated by one
or more filters through which the airflow passes, wherein the
hand-drying apparatus comprises a completely sealed
apparatus-housing that includes therein a fan-casing containing a
fan, wherein the fan is a dual-fan comprising two fan-halves each
of which is adapted to draw in airflow into the fan-casing.
16-34. (canceled)
35. An airflow system adapted to enhance airflow in a hand-drying
apparatus which expels a stream of substantially sterilised, hot
air that is heated by a heating-means for drying of hands, where
the airflow inside the apparatus is decelerated by one or more
filters through which the airflow passes, wherein the system is
provided with an airflow-pathway that is progressively smaller
along its pathway in respect of flowthrough cross-section, such
that, in use, the airflow is enhanced by flowing initially through
a larger part of the airflow-pathway, and subsequently through a
smaller part of the airflow-pathway after which the airflow exits
the apparatus.
36. A system of claim 35 where the airflow-pathway that is
progressively smaller along its pathway is provided downstream of
the heating-means.
37-38. (canceled)
Description
RELATED APPLICATIONS
[0001] This application claims priority to Australian Provisional
Patent Application No. 2007901255 in the name of Alpha Global
Holdings Pty Ltd, which was filed on 12 Mar. 2007, entitled
"Improved Airflow System & Apparatus and Method for Airflow
System" and, the specification thereof is incorporated herein by
reference in its entirety and for all purposes.
FIELD OF INVENTION
[0002] The present invention relates to airflow systems, and also
apparatus and methods for airflow systems, in particular,
appliances adapted to produce air movement, such as for example,
air dryers adapted to produce a stream of sterilised air for
`clean` drying conditions. In one form, the present invention is
suitable for use in hand dryers and it will be convenient to
hereinafter describe the invention as it relates to sterilising
hand dryers that produce a stream of sterilised, heated air,
particularly for drying hands, where airflow inside the apparatus
may be decelerated by one or more filters through which the airflow
passes. However, it should be appreciated that the invention is not
limited to that use, only.
BACKGROUND OF THE INVENTION
[0003] Throughout this specification the use of the word "inventor"
in singular form may be taken as reference to one (singular), more
than one (plural), or all (plural) inventors of the present
invention. The inventor has identified the following related
art.
[0004] Hand dryers may be used to emit a stream of heated or warm
airflow to dry a user's hands. These hand dryers are typically used
in public toilets, and in environments, such as in the medical
profession, where the user hopes to retain maximum cleanliness by
avoiding contact with potential bacteria-sources such as paper
towels, cloth towels or tissues.
[0005] It is often assumed that use of such hand drying apparatus
is more hygienic. Contrary to assumptions, however, the inventor
has found that these related art hand drying apparatus are actually
a mechanism for spreading germs. The warm airflow from these
related art hand drying apparatus is, itself, laden with airborne
bacteria. 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.
[0006] In the present applicant's corresponding International
Application PCT/AU2005/001803 (filed in the name of Panache Global
Holdings Pty Ltd), a plurality of filters are placed in the path of
the airflow through the dryer, each filter either having a function
of killing and/or removing bacteria particles, or effusing a
beneficial substance into the airflow, however, a problem is that
the airflow of the apparatus tends to be slowed down by these
filters, because the air has to pass through such a large number of
filters that impede the airflow.
[0007] At least one response to this problem may be to solely rely
on a larger, more powerful fan motor in the dryer that can provide
higher torque and faster fan-speed. In the related art, when
designers wished to have faster exit airflow speed, there may be a
tendency to use a faster, more powerful fan motor. But there would
be problems with this approach of solving the problem by solely
using a larger fan motor, for example, as follows:
[0008] First, it must be remembered that the ambient air of a
public toilet can often be laden with airborne bacteria. Therefore,
without being limited by theory, it is believed that using a larger
fan-motor may result in a stronger suck-in rate of air entering the
dryer. The present inventor reasons that a greater rate of incoming
airflow, into the dryer, may mean a greater amount of bacteria
entering into the dryer. Hence, a more powerful motor, with its
associated faster suck-in rate, may not be the most ideal solution
to the problem.
[0009] Secondly, faster fan-motors tend to be more expensive, and
can tend to have a greater amount of internal wear and tear,
tending towards shorter lifespan of the motor.
[0010] Thirdly, larger fan-motors can run hotter, and can tend to
produce more noise.
[0011] Fourthly, faster fan-motors tend to be larger, leading to
motors burning out, which may require the apparatus-housing of the
dryer to be larger to accommodate the larger motor.
[0012] In general, the inventor has identified that, in motors that
may be used for appliances adapted for air movement, the carbon
brush life may not be sufficient to meet the specification of the
appliance. Further, the inventor has identified that the speed of
motors in such appliances may be too low to overcome back pressure
that may build up. This has been particularly noted by the inventor
with respect to appliances that make use of the present applicant's
bactericidal filter system, with respect to impeded air flow
through an appliance. Further, commutators used for motors in such
applications as the above noted appliances may be normally `shell
type` commutators. Shell type commutators are generally
manufactured from a copper strip and moulded material such as
phenolic thermoset moulding material. The copper strip may be
blanked and formed, the formed copper shell is then moulded with
the thermoset moulding material such as phenolic as noted. After
moulding, the copper shell is separated into the required
individual bars or segments. This type of commutator is suitable
for low to moderate operating speeds and low electrical currents.
However, at higher speeds and higher electrical currents the risk
exists of individual segments or bars moving or lifting. The reason
for this effect may be attributed to the fact that the material
used to mould the commutator (eg Phenolic Thermoset and equivalent
materials) may not adhere to the copper and, as the inventor has
identified, the bond may be only mechanical in nature. Should a
commutator bar lift, move or distort through heat or rotational
speed, the motor may start sparking and destroy itself. At the very
least it may drastically reduce the carbon brush life of the motor.
Some attempts have been made to improve upon commutator design such
as disclosed in U.S. Pat. No. 5,491,373 (Cooper et al) where a
non-conducting ring is embedded in the internal core of the device
and is in contact with copper conductor.
[0013] With respect to the example of hand dryers, it is desirable
to reduce hand drying time, which only contributes to one or more
of the above noted drawbacks.
[0014] An additional difficulty that the inventor has identified
with respect to appliances providing air movement is that testing
and operating conditions may often tend to be opposite in their
specifications. For example, it may be a requirement that the
testing of a motor for providing air movement in an appliance is
performed with the motor under continuous operation. In direct
contrast, in normal operating conditions for the appliance, the
motor may be required to work in short intervals, such as about 30
seconds, at full performance or in other words, up to full load for
short intervals over a relatively long expected lifetime.
[0015] It has also been recognised that motors used to address the
above difficulties may be modified to perform outside of their
standard operating range and accordingly may be subject to
failure.
[0016] An object of the present invention is to overcome or at
least ameliorate one or more of the problems in the related art, or
to provide an improved alternative.
[0017] In particular, an object of the present invention is to
provide at least an improved alternative to the option of simply
providing a larger fan-motor, when confronted by the problem of one
or more filters decelerating the airflow through a hot air hand
drying apparatus.
[0018] In this specification, discussion of related art, either
individually or in combination, should not be construed as an
admission of any state of the common general knowledge of the
skilled addressee in this field of art of sterilising hand
dryers.
[0019] The present invention excludes from its scope those
sterilising hand dryers that do not use filters in the path of the
internal airflow, since such dryers would not have to address the
present problem of decelerated airflow resulting from the filters
being placed in the airflow path.
SUMMARY OF INVENTION
[0020] The present specification contains more than one aspect of
the present invention.
[0021] According to a first aspect of the present invention, there
is provided an airflow system adapted to enhance airflow in a
hand-drying apparatus which expels a stream of substantially
sterilised, hot air that is heated by a heating-means for drying of
hands, where the airflow inside the apparatus is decelerated by one
or more filters through which the airflow passes,
[0022] wherein the system, downstream of the heating-means, is
provided with an airflow-pathway that is progressively smaller
along its pathway in respect of flowthrough cross-section,
[0023] such that, in use, the airflow is enhanced by flowing
initially through a larger part of the airflow-pathway,
[0024] and subsequently through a smaller part of the
airflow-pathway after which the airflow exits the apparatus.
[0025] The airflow-pathway may include at least a part that has a
degree of taper.
[0026] The degree of taper is able to be selectively varied by the
user.
[0027] The degree of taper of the airflow-pathway may be able to be
selectively varied by the user substituting a replacement
airflow-pathway device of different size preferably selected from a
range of passageways of differing degrees of taper.
[0028] The airflow-pathway may include parts that are not
tapered.
[0029] The hand-drying apparatus, in which the system is adapted to
be used, may comprise a completely sealed apparatus-housing that
includes therein a fan-casing containing a fan.
[0030] In an exemplary embodiment, all airflow enters the
apparatus-housing through initial main-inlet-means on the
apparatus-housing,
[0031] and all airflow subsequently enters the fan-casing through
final main-inlet-means on the fan-casing,
[0032] wherein the initial main-inlet-means is larger than the
final main-inlet-means such that, in use, the airflow is enhanced
by flowing initially through the larger initial
main-inlet-means,
[0033] and subsequently through the smaller final
main-inlet-means.
[0034] The larger initial main-inlet-means and the smaller final
main-inlet-means may have flowthrough cross-sections which have a
ratio of around 1.38 relative to one another.
[0035] The fan may be a dual-fan comprising two fan-halves each of
which is adapted to draw in airflow into the fan-casing.
[0036] The airflow inside the apparatus is decelerated by a
plurality of filters
[0037] The airflow through the system may be driven by a fan
apparatus that is activated by a universal commutator motor.
[0038] According to a second aspect of the present invention, there
is provided a method of enhancing airflow through a hand-drying
apparatus that expels a stream of substantially sterilised, hot air
that is heated by a heating-means for drying of hands, where the
airflow inside the apparatus is decelerated by one or more filters
through which the airflow passes,
[0039] wherein the method includes providing the apparatus with an
airflow system which, downstream of the heating-means, includes an
airflow-pathway that is progressively smaller along its pathway in
respect of flowthrough cross-section,
[0040] and, in use, enhancing the airflow by causing the airflow to
flow initially through a larger part of the airflow-pathway,
[0041] and subsequently through a smaller part of the
airflow-pathway after which the airflow exits the apparatus.
[0042] According to a third aspect of the present invention, there
is provided a hand-drying apparatus airflow system adapted to
enhance airflow in an apparatus that expels a stream of
substantially sterilised, hot air that is heated by a heating-means
for drying of hands, where the airflow inside the apparatus is
decelerated by one or more filters through which the airflow
passes,
[0043] wherein the hand-drying apparatus comprises a completely
sealed apparatus-housing that includes therein a fan-casing
containing a fan,
[0044] wherein the fan is a dual-fan comprising two fan-halves each
of which is adapted to draw in airflow into the fan-casing.
[0045] According to a fourth aspect of the present invention, there
is provided a universal commutator motor adapted to drive an
appliance for providing air movement, the motor comprising:
[0046] magnetic field generating means for generating a magnetic
field;
[0047] a rotating armature adapted for rotational motion in
operative association with the magnetic field;
[0048] wherein a ratio of magnetic field strength at the armature
to the magnetic field strength within the magnetic field is less
than about 1 to 1.
[0049] The ratio of magnetic field strength may be about 0.9 to
1.
[0050] The armature may comprise:
[0051] a lamination armature structure having an arc of winding of
about slot 1 to about slot 11 and about slot 12 to about slot 22,
respectively.
[0052] The motor may further comprising:
[0053] at least two carbon brushes;
[0054] at least two brush holders operatively associated with the
at least two carbon brushes;
[0055] wherein flexible conducting material is adapted to provide
electrical connection to a commutator under variable operating
conditions.
[0056] The flexible conducting material may comprise braided copper
wire.
[0057] The motor may further comprise:
[0058] a commutator comprising a reinforcing ring located within
the body of the commutator such that it is isolated from conducting
segments and adapted to substantially reduce bar to bar
movement.
[0059] According to a fifth aspect of the present invention, there
is provided a universal commutator motor adapted to drive an
appliance for providing air movement, the motor comprising:
[0060] magnetic field generating means for generating a magnetic
field;
[0061] a rotating armature adapted for rotational motion in
operative association with the magnetic field, wherein a ratio of
magnetic field strength at the armature to the magnetic field
strength within the magnetic field is less than about 1 to 1;
[0062] wherein the armature comprises a lamination armature
structure having an arc of winding of about slot 1 to about slot 11
and about slot 12 to about slot 22, respectively;
[0063] at least two carbon brushes;
[0064] at least two brush holders operatively associated with the
at least two carbon brushes wherein flexible conducting material is
adapted to provide electrical connection of the carbon brushes to a
commutator under variable operating conditions; and,
[0065] the commutator comprises a reinforcing ring located within
the body of the commutator such that it is isolated from conducting
segments and adapted to substantially reduce bar to bar
movement.
[0066] The appliance for providing air movement may comprise an air
dryer.
[0067] According to a sixth aspect of the present invention, there
is provided a method of operating a universal commutator motor, the
motor adapted to drive an electric appliance for providing air
movement, the method comprising the steps of:
[0068] generating a magnetic field within the motor;
[0069] operatively associating a rotating armature of the motor
with the magnetic field;
[0070] maintaining a ratio of magnetic field strength at the
armature to the magnetic field strength within the magnetic field
at less than about 1 to 1.
[0071] The ratio of magnetic field strength may be about 0.9 to
1.
[0072] The method may further comprise the step of:
[0073] providing an increased magnetized area for the armature
corresponding to a lamination armature structure having an arc of
winding of about slot 1 to about slot 11 and about slot 12 to about
slot 22, respectively.
[0074] The method may further comprise the steps of:
[0075] providing at least two carbon brushes;
[0076] providing at least two brush holders operatively associated
with the at least two carbon brushes;
[0077] provide electrical connection to a commutator under variable
operating conditions by use of flexible conducting material adapted
to provide electrical connection to a commutator under variable
operating conditions.
[0078] The flexible conducting material may comprise braided copper
wire.
[0079] The method may further comprise the steps of:
[0080] providing a commutator comprising a reinforcing ring located
within the body of the commutator such that it is isolated from
conducting segments and adapted to substantially reduce bar to bar
movement.
[0081] According to a seventh aspect of the present invention,
there is provided a method of operating a universal commutator
motor, the motor adapted to drive an electric appliance for
providing air movement, the method comprising the steps of:
[0082] operatively associating a rotating armature of the motor
with the magnetic field;
[0083] maintaining a ratio of magnetic field strength at the
armature to the magnetic field strength within the magnetic field
at less than about 1 to 1;
[0084] providing an increased magnetized area for the armature
corresponding to a lamination armature structure having an arc of
winding of about slot 1 to about slot 11 and about slot 12 to about
slot 22, respectively;
[0085] providing at least two carbon brushes;
[0086] providing at least two brush holders operatively associated
with the at least two carbon brushes;
[0087] providing electrical connection to a commutator under
variable operating conditions by use of flexible conducting
material adapted to provide electrical connection of the carbon
brushes to a commutator under variable operating conditions;
and,
[0088] providing a commutator comprising a reinforcing ring located
within the body of the commutator such that it is isolated from
conducting segments and adapted to substantially reduce bar to bar
movement.
[0089] The appliance for providing air movement may comprise an air
dryer.
[0090] The appliance for providing air movement may comprise a
hand-drying apparatus airflow system as described.
[0091] According to a eighth aspect of the present invention, there
is provided an airflow system adapted to enhance airflow in a
hand-drying apparatus which expels a stream of substantially
sterilised, hot air that is heated by a heating-means for drying of
hands, where the airflow inside the apparatus is decelerated by one
or more filters through which the airflow passes,
[0092] wherein the system is provided with an airflow-pathway that
is progressively smaller along its pathway in respect of
flowthrough cross-section,
[0093] such that, in use, the airflow is enhanced by flowing
initially through a larger part of the airflow-pathway,
[0094] and subsequently through a smaller part of the
airflow-pathway after which the airflow exits the apparatus.
[0095] In this eighth aspect, the airflow-pathway, that is
progressively smaller along its pathway, may be provided downstream
of the heating-means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0096] In order that the present invention might be more fully
understood, embodiments of the invention will be described, by way
of example only, with reference to the accompanying drawings, in
which:
[0097] FIG. 1A is a front view of an embodiment of a sterilising
hand-drying apparatus which has a internal airflow that is
decelerated by several filters, and which incorporates an
embodiment of an improved airflow system that enables enhanced
airflow through the apparatus;
[0098] FIG. 1B is a side view of the hand-drying apparatus of FIG.
1A;
[0099] FIG. 1C is an underside view of the bottom of the
hand-drying apparatus of FIG. 1A;
[0100] FIG. 2 is a rear perspective view of the hand-drying
apparatus of FIG. 1A, when the apparatus-housing is opened to
reveal its interior, and when viewed from the perspective of arrow
A in FIG. 1B;
[0101] FIG. 3 shows a perspective view of an embodiment of four
main filter holders that hold filters, with the first holder shown
with its filter withdrawn, being filters that decelerate airflow in
the embodiment of FIG. 1A;
[0102] FIG. 4A shows a perspective view of an embodiment of a
fan-casing and a fan motor, with a pair of subsequent filter
holders and filters which are attached to the fan-casing;
[0103] FIG. 4B shows an exploded view of the apparatus of FIG. 4A,
showing an embodiment of a dual fan that is contained inside the
fan-casing;
[0104] FIG. 4C shows a further exploded view of the apparatus of
FIG. 4A, showing more details of the dual fan;
[0105] FIG. 4D is a side, cross-sectional view of the dual-fan of
FIGS. 4B and 4C;
[0106] FIGS. 4E and 4F are side views of the dual-fan of FIGS. 4B,
4C and 4D, each viewed from a different side of the fan
respectively;
[0107] FIG. 4G is a section view of the embodiment of the dual-fan
in FIGS. 4B, 4C, 4D, 4E and 4F.
[0108] FIG. 5 shows three different embodiments of exit-passageways
that can be used interchangeably in the embodiment of FIGS. 1A to
2, each embodiment have a different degree of taper through which
airflow leaves the fan-casing and exits the hand-drying
apparatus;
[0109] FIG. 6A shows a plan view of an example arc winding in
relation to a lamination arm in an electric motor in accordance
with at least one related art technique identified by the
inventor;
[0110] FIG. 6B shows a plan view of arc winding in an electric
motor in accordance with a preferred embodiment;
[0111] FIG. 6C is a plan view of a field assembly of a universal
motor with an exploded view of its components in accordance with a
preferred embodiment;
[0112] FIG. 6D is a component parts listing for the field assembly
of FIG. 6C;
[0113] FIG. 6E is plan view of a brush commutator housing assembly
of a universal motor with an exploded view of its components in
accordance with a preferred embodiment;
[0114] FIG. 6F is a component parts listing for the brush
commutator housing assembly of FIG. 6E;
[0115] FIG. 6G is plan view of an armature assembly of a universal
motor with an exploded view of its components in accordance with a
preferred embodiment;
[0116] FIG. 6H is a component parts listing for the armature
assembly of FIG. 6G;
[0117] FIG. 6I is a plan view of a drive end housing assembly of a
universal motor with an exploded view of its components in
accordance with a preferred embodiment;
[0118] FIG. 6J is a component parts listing for the drive end
housing assembly of FIG. 6I;
[0119] FIG. 6K(a) shows a commutator of a preferred embodiment of
the present invention in top plan view;
[0120] FIG. 6K(b) shows a cross sectional side view of the
commutator of FIG. 6K(a) taken along the direction of line A-A in
FIG. 6K(a); and
[0121] FIG. 6K(c) is an expanded view of section B in FIG.
6K(b).
[0122] In the embodiments, like components are labeled with like
reference numerals merely for the sake of ease of understanding the
different embodiments and modifications.
DETAILED DESCRIPTION
[0123] Referring to the accompanying drawings, FIG. 1A shows a
front view of a sterilising hand-drying apparatus in the form of a
hand dryer 1.
[0124] FIG. 1B shows a side view of the dryer 1, and FIG. 1C shows
an underside view of the same dryer 1.
[0125] FIG. 2 shows a rear perspective view of the dryer 1 when it
is opened, showing its interior.
[0126] The dryer 1 draws in ambient air. Bacteria in the airflow is
killed and preferably removed. The airflow is heated, and then
expelled from the dryer, typically directly onto the user's hands
for drying.
[0127] In FIG. 2, the hand dryer 1 has an apparatus-housing 10, 11
which includes a main hood 10 and a baseplate 11. The hood 10 is
mounted to the baseplate 11 by hinges 12.
[0128] The baseplate 11 can be secured to a wall with screws, bolts
or other appropriate fastening mechanism.
[0129] FIG. 1A shows the hood 10 arranged in a closed position,
installed ready for use, for example, mounted on a wall.
Air-Flow
[0130] The hand dryer 1 is adapted to expel an airflow or stream of
substantially sterilised, hot air for drying hands. In the
embodiment, the operational range of the heated air is around 55 to
65 degrees Centigrade.
[0131] In summary, when the dryer 1 is operated to dry a user's
hands, ambient air is sucked into the apparatus housing, then
heated, and expelled from the apparatus.
[0132] Air is sucked into the dryer 1 (depicted by arrow 200A in
FIG. 1A), and eventually is expelled from the dryer (depicted by
arrow 200E in FIG. 1A).
Main Filters
[0133] (FIG. 1A is a front view, whereas FIG. 2 is a rear view. In
FIG. 1A, the airflow 200A enters the dryer in the region of the
left hand side of the diagram. Whereas, in FIG. 2, the incoming
airflow 200A would enter the dryer 1 in the region of the right
hand side of the drawing).
[0134] In FIG. 2, inside the dryer 1, the incoming air 200A passes
through a main-filter assembly 410. In the embodiment, this main
filter assembly includes four main filter holders 410A, 410B, 410C,
410D (seen in more detail in FIG. 3).
[0135] The function of these main filter holders and their filters
is to kill and remove bacteria particles, to the extent that in the
embodiment, the airflow can be made substantially bacteria-free,
and preferably 100% bacteria-free. The features of an example o the
filters, and their role in killing bacteria, is described in the
present inventor's earlier corresponding International Patent
Application PCT/AU2005/001803 (filed in the name of Panache Global
Holdings Pty Ltd), which is incorporated herein by reference into
this present description merely as a non-limiting example of the
function of these filters. The information in PCT/AU2005/001803
explains how an exemplary embodiment of a dryer is able to expel a
substantially bacteria-free airflow, preferably a 100%
bacteria-free airflow.
Subsequent Filters
[0136] In this embodiment, after the airflow passes through the
filters of the main filter holders 410A, 410B, 410C, 410D, the
airflow is drawn towards a fan-casing 400A, 400B that contains a
fan.
[0137] Part of the airflow enters the fan-casing through one 400A
of the sides of the casing, passing through the filters of some
subsequent filter holders 420A, 420B. The purpose of these
subsequent filters, which are further upstream, is to effuse and
add beneficial substances to the airflow. For example, the filters
of one of these subsequent filters 420A or 420B can effuse another
anti-bacterial substance into the airflow.
[0138] This subsequent anti-bacterial substance, effused from the
filters of the subsequent holders 420A or 420B, stays in the
airflow until it is expelled from the dryer 1 in the exit airflow
200E, where the substance can become coated onto the hands of the
user.
[0139] Any one or more of the filters, from either the main
holders, preferably the latter ones 410C, 410D, or from the
subsequent holders 420A, 420B, can be used to effuse a beneficial
substance into the airflow.
[0140] That substance can be ultimately coated onto the hands of
the user when it exits the dryer 1, or alternatively the substance
can spread into the ambient air surrounding the hand dryer 1. For
example, a fragrance can be effused into the airflow so that the
washroom atmosphere smells pleasant. As another example, an
anti-bacterial substance can be effused into the washroom
atmosphere to minimise airborne bacteria.
[0141] Many people that use public toilets, after washing their
hands, are slightly uneasy about having to touch the bacteria-laden
doorhandles of the toilet door. It almost defeats the purpose of
washing hands, if bacteria will return immediately by touching the
dirty toilet door handle. Some users try to open the door with the
feet, to avoid touching the door handle. In the embodiment, the
airflow coats the user's hands with a small amount of the
expellable-substance. For example, the user's hands can be coated
with a small amount of an anti-bacterial substance. In the
embodiment, the amount is sufficient to provide a greater degree of
protection for the user's hands when touching the bacteria-coated
handle of the toilet door.
[0142] In some examples, the effused substance on the hands of user
may be of a sufficient amount to feel like a cream on the hands.
This gives the user tangible evidence that something beneficial has
been coated onto the hands.
[0143] Some examples of substances, that can be effused into the
airflow for this purpose, are described in the present inventor's
corresponding International Patent Application PCT/AU2006/001815
(filed in the name of Panache Global Holdings Pty Ltd), which is
incorporated herein by reference into this present description
merely as a non-limiting example of chemical substances that can be
thus effused into the airflow.
[0144] It is preferable to effuse the expellable-substance from a
subsequent filter (420A or 420B) that is located on the fan-casing
400A, 400B, rather than from the earlier main filters holders 410A,
410B, 410C, 410D. This ensures that substantially all the
expellable-substance will enter the fan-casing. If, on the other
hand, the expellable-substance were to be effused primarily using
one of the main filters in the main filter holders 410A, 410B,
410C, 410D, then a portion of the expellable-substance may
otherwise deposit on internal surfaces of the housing 10, 11. This
depends of the nature of the expellable-substance, and so the user
should decide where the optimum location for a filter, that
contains a particular expellable-substance, is on the main filter
holders 410A, 410B, 410C, 410D, or on the subsequent filter holders
420A, 420B.
[0145] After the airflow is drawn into the fan-casing 400A, 400B,
it is expelled from the dryer 1, through an exit-nozzle 14 as an
outflow 200E of air.
Filter Options
[0146] The number of filters, used in practice, is determined by a
user of the dryer 1 who may be responsible for installation and/or
maintenance.
[0147] FIGS. 3 and 4C show that the filters can be removed from
their holders 410A, 410B, 410C, 410D and 420A, 420B. For example,
when the active ingredient in a particular filter has reached its
lifespan, the maintenance user can replace the filter with a new
filter.
[0148] As another example, different filters can contain different
active ingredients that are intended to be infused into the
airflow, hence, the maintenance user can purchase different filters
to suit the particular need. For instance, the substance that are
effused into the airflow, for use by medical staff such as
surgeons, might differ from different substances that are effused
in dryers used in public toilets, for example.
Air Heater
[0149] Referring to FIG. 4A, the dryer 1 is provided with an
electric heating element 4 (not shown in detail). The heating
element is located at a heating means location 5 which is close to
an opening of the fan-casing 400A, 400B, behind a protective grille
15. The heating element includes a grid of wires or plates adapted
to be heated up electrically when the dryer 1 is emitting the hot
airflow 200E.
Initial-Main-Inlet & Final-Main-Inlet
[0150] In the embodiment, it is a requirement that the housing 10,
11 of the dryer 1 is completely sealable, for instance with rubber
gasket seals. The complete sealing of the housing is achieved by
providing seals at all points of contacting between the main hood
10 and the baseplate 11. The sealing is to such a degree that, when
the housing 10, 11 is closed, absolutely all air entering the dryer
1 must pass through an initial-main-inlet in the form of the
initial main aperture 405A. This ensures that all incoming air will
be filtered by the filters in the main filter holders 410A, 410B,
410C, 410D. If not, then any air that were to leak into the
housing, other than through the initial-main-inlet, would not be
subjected to filtration through the filters in the main holders
410A, 410B, 410C, 410D.
[0151] Hence, all of the airflow that enters the dryer 1 through
the initial main aperture 405A, must pass through the sequence of
filters in the holders 410A, 410B, 410C, 410D.
[0152] In the embodiment of FIG. 1A, there is only one initial main
aperture 405A, however, in other embodiments, the initial opening
can be divided into several openings, provided that the combined
area of the plurality of initial-main-inlets is larger than the
area of the final-main-inlet on the fan-casing.
[0153] The air then enters into a chamber area inside the
completely-sealed, closed housing. (The apparatus has a cut-off
switch so that the airflow cannot be generated when the housing is
open).
[0154] Next, the airflow is drawn, from the chamber, into the
fan-casing 400A, 400B.
[0155] Part of the airflow enters the fan through the
final-main-inlet in the form of final main apertures 405B, which is
the part 400A of the fan-casing that is filtered by the filters in
the subsequent filter holders 420A, 420B.
[0156] Another part of the airflow is drawn into the fan-casing
through another portion of the final-main-inlet in the form of
final main apertures 405C, which is the part 400B of the fan-casing
that is not filtered, and which is closer to the fan motor 430.
Fan
[0157] The airflow through the dryer 1 is created by a fan 401,
shown in FIGS. 4B, 4C and 4D. The fan rotates inside the fan-casing
400A, 400B.
[0158] The rotation of the fan 401 is operated by a motor 430. In
the example, the motor may be a universal motor capable of up to or
greater than a speed of 7500 rpm under operating conditions and is
discussed further herein.
[0159] In the embodiment, the fan blade 401 is made of
injection-moulded plastic. The fan should not be made of a material
that would readily shatter of extremely high rotation speeds. Also,
the fan should not be so flexible that it would warp at high
rotation speeds. The fan of the embodiment is made of a nylon
composite material, although other suitable materials can be
used.
Dual Fan-Blade
[0160] By way of background, the filters in the filter holders
410A, 410B, 410C, 410D and 420A, 420B tend to decelerate the
airflow through the dryer.
[0161] A feature that at least ameliorates this problem is to make
the fan 401, in the embodiment, to be a dual-fan, seen in FIGS. 4C
and 4D.
[0162] The dual-fan has two regions that each has a similar
function to a normal single fan. In other words, one fan item acts
as if it were two fans.
[0163] In FIG. 4D, even though the fan 401 is manufactured as a
single item, it is regarded as a dual-fan, because it has two
separate fan regions, which are separated by a central web 403 that
extends from a central, axial spindle 404. The spindle 404 is
connected to the drive shaft (not shown) of the motor 430.
[0164] In the embodiment, the dual-fan consists of two
fan-halves.
[0165] FIG. 4D shows a cross-sectional view of the two halves of
the fan-halves 402A, 402B in cross-section.
[0166] FIG. 4E shows a side view of the fan 401, showing the
fan-half 402A that is closer to the final main aperture 405B that
is filtered.
[0167] Similarly, FIG. 4F shows the other side of the same fan,
showing the fan-half 402B that is closer to the opposite final main
aperture 405C which is nearer the fan-motor 430.
[0168] FIGS. 4E and 4F show that the circumferential rim of the fan
401 is provided with a series of fan-blades 406 evenly disposed
around the circular rim. When these fan-blades 406 rotate, air is
draw into the fan-casing, thereby also causing ambient air to be
sucked into the dryer 1.
[0169] FIG. 4G is similar to FIG. 4D, except that the present FIG.
4G shows a section view, or "slice view", of the dual-fan 401, when
a slice is taken along the dotted line 407 in FIG. 4E. The
embodiment of the dual-fan could be described roughly as having a
cylindrical outer rim, which carries the fan blades, where the
cylinder has a central partition or central web 403. The central
web divides the cylinder roughly into two halves.
[0170] Without being limited by theory, it is believed that the use
of the dual-fan lessens the degree of turbulence in the airflow
that is expelled from the fan. It is believed that the airflow,
coming out of the dual-fan, is more streamlined, with less
turbulence, compared to the airflow that would come from a single,
non-dual fan. It is believed that an advantage of having less
turbulence is that there would be less likelihood of back-pressure
building up particularly inside the fan and the exit nozzle 14.
Therefore, the dual-fan is able to contribute to the enhanced
airflow, for example, by minimizing the occurrence of internal
turbulence in the airflow that is expelled from the fan via the
exit nozzle 14.
[0171] It is an advantage to minimize back-pressure in the exit
nozzle 14, because back-pressure can, amongst other things, slow
down the exit airflow and/or increases the level of noise.
[0172] In the side cross-sectional view of FIG. 4D, the fan is
slightly tapered, in the sense that the diameter of the first
fan-half 402A is slightly smaller than the diameter of the second
fan-half 402B. In other words, the cross-section of the dual-fan is
slightly frusto-conical.
Exit Nozzle
[0173] As mentioned, the filters in the filter holders 410A, 410B,
410C, 410D and 420A, 420B have a detrimental effect of decelerating
the airflow through the dryer.
[0174] A feature that at least ameliorates this problem is to
provide the airflow system, of the dryer 1, downstream of the
location 5 of the heater, with an airflow-pathway that is
progressively smaller along its pathway in respect of flowthrough
cross-section.
[0175] In the embodiment, the airflow-pathway is in the form of the
exit nozzle 14 that is downstream from the heater location 5. The
nozzle 14 is tapered, so that it fulfils the criteria of being
progressively smaller along its pathway in respect of flowthrough
cross-section. The airflow is enhanced by flowing initially through
a larger part of the nozzle, and subsequently through a smaller
part of the nozzle.
[0176] Airflow velocity tends to increase, when it is forced to
flow through progressively smaller flowthrough cross-sections of
the nozzle 14.
[0177] The airflow exits the dryer 1 through an outlet-means in the
form of the exit nozzle 14.
[0178] Providing the exit-nozzle 14 with a tapered passageway
enables a faster speed of the exit airflow 200E, without, at the
same time, necessarily requiring a larger and faster fan-motor,
which may result in the associated problems, as discussed in the
above preamble of this specification.
[0179] In the embodiment of FIG. 2, the exit nozzle 14 has a taper
of around 7 degrees to the vertical, however, the degree of taper
in other embodiments can be modified. FIG. 5 shows several other
alternative embodiments 14A, 14B, 14C of nozzles with different
degrees of tapering.
[0180] When the dryer 1 is used in different environments by a
range of users, each end-use situation may have different
requirements.
[0181] Another criteria is that the degree of taper can affect the
noise level as airflow rushes through the nozzle 14.
Different Uses
[0182] In some environments, the user requires the exit airflow to
be as fast as possible. For example, when effusing a beneficial
substance in the airflow, the need is to spread that beneficial
substance as far as possible into the ambient environment outside
the dryer 1. For example, such an aim occurs in a public toilet or
washroom where it is desirable to effuse a fragrance throughout the
atmosphere of a washroom. This requires the exit airflow 200E to be
as fast as possible, so that it can have a chance to reach the
furthest reaches of the washroom. This application can benefit from
a narrower nozzle 14C in FIG. 5.
[0183] In other uses, while the speed of the exit airflow 200E
remains important, the end-user may prefer to have a wider size of
airflow to ensure that his hands are fully or effectively coated
with the beneficial substance that is in the exit airflow 200E.
This application can benefit from a slightly wider nozzle 14A in
FIG. 5.
[0184] In some other situations, there needs to be a compromise, so
that both the above applications can be achieved using one
apparatus. This application can benefit from a medium-sized nozzle
14B in FIG. 5.
[0185] The variation in the size of the nozzles produces different
sound noise, with smaller nozzles tending to produce louder noise
levels than the larger nozzles.
[0186] In the nozzles in FIG. 5, the different models of the
nozzles can be used interchangeably in the embodiment of FIG.
2.
Back Pressure
[0187] In the context of other parameters of the dryer 1, if the
degree of taper is too great, then a problem of back pressure can
occur. Without being limited by theory, it is believed that when
the degree of tapering is excessive, the desired laminar airflow
through the nozzle 14 can be compromised, and there can be a
reduction of the exit speed of the exit airflow 200E.
[0188] Hence, the problem of build-up of back pressure can occur
when the airflow cannot exit the dryer fast enough. This back
pressure can build up inside the nozzle, and possibly inside the
dryer.
[0189] Although tapering of the nozzle can enhance the exit speed,
on the other hand, excessive tapering can inadvertently slow down
the airflow speed, due to build-up of back pressure. Hence, when
the designer is determining the limit of tapering beyond which back
pressure occurs, it is also necessary for the designer to consider
a number of other parameters of the dryer.
[0190] In the present embodiment, the optimum taper was found to be
about 7 degrees to the vertical, however, some experimentation may
be required when the dryer is modified in terms of its shapes of
the internal chamber, the design and power of the fan-motor, the
diameter of the fan, the length of the nozzle, the number of
filters, the degree of internal surface smoothness of the nozzle,
and other variables that affect the overall speed of airflow
through the dryer. All these factors can influence the optimum
degree of taper for a particular embodiment of a dryer.
Modifications of the Nozzle
[0191] In other modifications, there can be different means of
achieving an airflow-pathway that is progressively smaller along
its pathway in respect of flowthrough cross-section.
[0192] For example, the nozzle can consist of an initial
non-tapered region having a larger flowthrough cross-section, which
is followed by a subsequent non-tapered region having a smaller
flowthrough cross-section. In other words, this feature is not
limited to embodiments that have tapering.
[0193] In some other embodiments, the degree of tapering of the
nozzle is not only defined in terms of slope, but can also be
defined in terms of the transition from, for example, a square
cross-section at one end of the nozzle, can transition to a
circular or differently-shaped aperture at the other end of the
same nozzle.
[0194] There can be a variation of noise level of airflow through
different nozzles, and so this must be considered in the context of
the nature of the use of the dryer. Some environments may be more
or less critical of high noise levels.
Enhancement of Airflow
[0195] In the specification, the notion of enhanced airflow does
include the concept of having faster airflow, however, the notion
of enhanced airflow also includes the concept of maintaining a
suitable airflow through and out of the dryer 1, in spite of the
decelerating effect of the filters. In other words, the enhancement
comes from overcoming the deceleration that normally would occur
when one or more filters would otherwise impede the airflow inside
the dryer to a detrimental degree.
[0196] Hence, in some embodiments, the invention is able to, but
not necessarily limited to, achieving faster airflow.
[0197] The invention may include cases where the airflow speed is
not substantially reduced, even with the use of one or several
impeding filters, compared to a situation where none of the
improved features of the present embodiments were incorporated in
the dryer.
Motor Design
[0198] The airflow, that flows through the airflow system in the
hand dryer 1, is driven by the fan 401. In the embodiment, the fan
is rotated and thus activated by a universal commutator motor.
[0199] In providing the dryer 1 with a motor to address the
problems identified hereinabove and meet the requirements of an
appliance such as a sterilising hand drying apparatus described
herein, the inventor has identified a need to establish a
relationship between the stationary field of preferably a universal
motor and its rotating armature. The failing of motors of this type
is very often the result of the failing of the bearing due to
overheating which may result in the leaking out of lubricant
resulting in at least one of the following: Noisy Bearing; Higher
Friction; More Heat generated to overcome the friction and the
final result may be the burning out of the motor. Accordingly, the
magnetic relationship has been established to achieve a relatively
cooler Armature. The traditional design of universal motors
attempts to keep the magnetic force (or magnetic field strength) at
a ratio of 1 to 1 between armature and stationary field.
[0200] In the magnetic relationship established in accordance with
a preferred embodiment, a ratio of less than 1 to 1 is provided.
Preferably, the ratio is about 0.9 to 1. This provides for a cooler
armature when operating even up to full power corresponding to full
load on the motor. In fact, the inventor has found that this
relationship contributes to an increase in power at the same time
as a reduction in heat dissipation from the armature.
[0201] With reference to FIGS. 6A and 6B showing a lamination arm
600 in plan view, it is further preferable in accordance with
embodiments to increase the magnetised area of the armature of a
universal motor. As shown in FIG. 6A, traditional motors provide an
arc of winding 601, 602 from slot 2 to 10 to slot 12 to 20. The
inventor has found that it is advantageous to provide an arc of
winding of about slot 1 to 11 and about slot 12 to 22,
respectively. In FIG. 6A and 6B the magnetic field is shown in
accordance with convention in which crosses within the lamination
arm structure indicate the direction of the field to be heading out
of the plane of the page and circular markings within the
lamination arm structure indicate the direction the magnetic field
to be heading into the plane of the page.
[0202] Further, it has been found to be advantageous to provide for
a positive electrical connection at all operating times between
brushes and the commutator.
[0203] Preferably, at least one Carbon Brush and Brush Holder may
be modified to provide good electrical connection and flexible
conductor is preferably used to ensure a positive electrical
connection at all times.
[0204] In an exemplary embodiment, two carbon brushes and brush
holders, i.e. two carbon brushes each with a brush holder, may be
modified to provide the good electrical connection and flexible
conductor.
[0205] In this respect, it is preferable to provide flexible
braided copper wire inserted into the carbon brush at one end
thereof the brush and have the copper attached, for example,
soldered or crimped, at the other end to the terminal connecting to
the field wiring. Other suitable materials for the flexible
conductor may be silver, brass or other conducting materials which
would be recognised by the person skilled in the art. A commutator
of high performance grading with a reinforcing ring may be used to
substantially eliminate any Bar to Bar movement at high speed. With
reference to FIG. 6K(a) to 6K(c), a solution provided in preferred
embodiments is to use a commutator 610 with individual copper
segments 611 and a conducting reinforcing ring 612 that is
positioned or located within the commutator body 613 at a distance
from the conductive segments 611 and moulded within the moulding
material 614 of the commutator 610. The conducting material used
for the reinforcing ring 612 may be a metal with sufficient
strength to provide suitable reinforcement under high speed
operation and durability to the commutator, for example, steel or
aluminium. The commutator 610 of FIG. 6K has the following
advantages which may ensure that the commutator bars or segments
611 do not lift or move even at high speeds:
[0206] A. The solid and rigid copper segment 611 will not get
distorted or bend even in elevated temperatures.
[0207] B. The reinforcing ring 612 which is moulded into the
commutator 610 acts like a reinforcing as in concrete.
[0208] C. The reinforcing ring 612 being made of a strong material
to provide rigidity to the commutator 610 and may be useful where
individual copper segments 611 are used in the commutator 610. It
is noted that the commutator of Cooper et al mentioned above may
not be applicable to such commutators.
[0209] With the above described features in mind, the universal
motor has been tested to operate at speeds in excess of 7,500 rpm.
For example, trials of the motor operating have given a free load
speed of up to 25,000 rpm +/-about 15-20%. Exemplary testing
results are noted below.
[0210] 3. Performance [0211] (1) Life test 30 seconds on/30 seconds
off for c.c.w. direction more than 500 hours. [0212] (2) Insulation
Grade Class E [0213] (3) Characteristic
TABLE-US-00001 [0213] Voltage AC 240 V/50 H.sub.Z No-load Input
220.0 W max No-load Current 0.95 A max. No-load Speed 25000 .+-.
15% R.P.M. Rated Torque 2.85 kg-cm Rated Current 2.55 .+-. 12% A
Rated Speed 12000 .+-. 12% R.P.M. Rated In-put 585.0 .+-. 12% W
[0214] 4. No-load Starting Voltage [0215] Less than 100 V at 50
H.sub.z
[0216] 5. Insulating Resistance [0217] More than 100 M ohm at
DC500V(under normal temp. & humidity)
[0218] 6. Dielectric Strength [0219] Withstand for 1500 V for 1
sec. 1.0 mA.
[0220] 7. Noise Less than 80 dB(A) when measured 1 meter from the
motor on unresonant rubber.
[0221] 8. Vibration No abnormal vibrations.
[0222] 9. Structure & Construction
TABLE-US-00002 (9-1) External Dimension As DWG. NO. W5R32 (9-2)
Shaft S45C o12.0 (9-3) Bearing ball bearing
(629-2RSLTN9&627-2Z) (9-4) Bracket 1.2 mm steel-cold dull black
(9-5) Commutator 22 seg (9-6) Poles 2 poles (9-7) Lead Wire 0.75
mm.sup.2 7.5 A PVC V90-110.degree. C. 250 V (9-8) Motor Weight 1.45
KGS (9-9) Thermal Protector VDE Licen NO: 104216 SEKI ST-22
105.degree. C. 10. Rotor End-play Less than 0.5 MM 11. Screw Clamp
Torque 15.0 kg-cm(screw 3/16''-24) & 10.0 kg-cm(screwM4 .times.
0.7)
[0223] The universal motor of preferred embodiments also comprises
a thermal fuse/protector as a useful safety and failsafe
addition.
[0224] The advantages provided with the above noted features of the
universal motor in combination are as follows.
[0225] The motor performs at lower armature temperature
[0226] The motor has a longer life expectancy
[0227] The motor is serviceable
[0228] The motor is suitable for short interval operation as well
as continuous operation
[0229] The motor can operate in higher ambient temperatures.
[0230] A preferred embodiment of the universal motor with suitable
components and example construction is illustrated in FIGS. 6C to
6J.
Synergy of Various Enhancing Features
[0231] The above description highlights a few features, each of
which, by themselves, is able to enhance or speed up the airflow of
the dryer when used alone in embodiments. In the embodiment, these
enhancing features include: the use of a dual fan, and/or provision
of the tapered exit nozzle and/or use of a suitable constant speed
motor.
[0232] However, where all these features are combined in the one
drying apparatus, as it is in the embodiment of FIGS. 1A to 2,
there is an added synergy when all those features act together to
further enhance the internal and exit airflow of the apparatus
beyond conventional expectations.
[0233] In the embodiment of FIGS. 1A to 2, the exit airflow 200E
can be around 72 m/s.
Other Modifications
[0234] In another modification, rather than substituting different
nozzles, a single nozzle can be designed with a mechanism that
allows the user to mechanically adjust the shape of the taper of
the nozzle, so that this one single user-variable nozzle can be
used in all environments.
[0235] The apparatus can be provided with multiple exit nozzles
that incorporate the principles of faster airflow, described
herein. Hence, the reference to a downstream exit airflow-pathway
includes the option of more airflow-pathways.
[0236] The system can be used with dryers that have one or more
filters, although the benefits of the system are best seen in
dryers that have a plurality of filters. For example, the
embodiment in FIG. 2 has potentially six filters that can each
decelerate the speed of the airflow.
[0237] 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.
[0238] In other modifications, it is conceivable and possible that,
in a further embodiment of the system, upstream of the
heating-means is provided with the airflow-pathway that is
progressively smaller along its pathway in respect of flowthrough
cross-section, i.e. in this embodiment, a or the heater is provided
at the end of the tapered nozzle.
[0239] In this specification, where the words comprise or comprises
or derivatives thereof are used in relation to elements, integers,
steps or features, this is to indicate that those elements, steps
or features are present but it is not to be taken to preclude the
possibility of other elements, integers, steps or features being
present.
* * * * *