U.S. patent application number 11/997305 was filed with the patent office on 2008-12-11 for drying apparatus.
This patent application is currently assigned to DYSON TECHNOLOGY LIMITED. Invention is credited to Paul Cedric Campbell Hackwell, Frederic Nicolas.
Application Number | 20080301970 11/997305 |
Document ID | / |
Family ID | 34983823 |
Filed Date | 2008-12-11 |
United States Patent
Application |
20080301970 |
Kind Code |
A1 |
Hackwell; Paul Cedric Campbell ;
et al. |
December 11, 2008 |
Drying Apparatus
Abstract
A drying apparatus having a casing, a cavity formed in the
casing for receiving an object, a fan located in the casing and
creating an airflow, and at least one slot-like opening
communicating with the fan and arranged in the casing to direct an
airflow transversely across the cavity. The slot-like opening is
formed between opposing walls which approach one another at an
angle of between 10.degree. and 20.degree.. In another aspect, two
slot-like openings are provided ducting providing communication
between the fan and the slot-like openings has a first
cross-section in the vicinity of the fan whose dimensions are
similar in all directions and a slot-like cross-section in the
vicinity of the openings, the transition between the said
cross-sections being gradual and smooth.
Inventors: |
Hackwell; Paul Cedric Campbell;
(Wiltshire, GB) ; Nicolas; Frederic; (Wiltshire,
GB) |
Correspondence
Address: |
MORRISON & FOERSTER LLP
1650 TYSONS BOULEVARD, SUITE 400
MCLEAN
VA
22102
US
|
Assignee: |
DYSON TECHNOLOGY LIMITED
Malmesbury
GB
|
Family ID: |
34983823 |
Appl. No.: |
11/997305 |
Filed: |
June 12, 2006 |
PCT Filed: |
June 12, 2006 |
PCT NO: |
PCT/GB2006/002144 |
371 Date: |
June 18, 2008 |
Current U.S.
Class: |
34/202 |
Current CPC
Class: |
A47K 10/48 20130101 |
Class at
Publication: |
34/202 |
International
Class: |
A47K 10/00 20060101
A47K010/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 30, 2005 |
GB |
0515739.1 |
Jan 17, 2006 |
GB |
0600880.9 |
Claims
1. A drying apparatus, comprising a casing, a cavity formed in the
casing for receiving an object, a fan located in the casing and
capable of creating an airflow, and at least one slot-like opening
communicating with the fan and arranged in the casing to direct an
airflow transversely across the cavity, wherein the slot-like
opening is formed between opposing walls which approach one another
at an angle of between 10.degree. and 20.degree..
2. The drying apparatus as claimed in claim 1, wherein the opposing
walls approach one another at an angle of about 14.degree..
3. A drying apparatus having comprising a casing, a cavity formed
in the casing for receiving an object, a fan located in the casing
and creating an airflow, and two opposing slot-like openings
communicating with the fan via ducting and arranged in the casing
to direct an airflow transversely across the cavity, wherein the
ducting has a first cross-section in the vicinity of the fan whose
dimensions are similar in all directions and a slot-like
cross-section in the vicinity of the openings, a transition between
the said cross-sections being gradual and smooth.
4. The drying apparatus as claimed in claim 3, wherein the total
cross-sectional area of the ducting is substantially constant
between the fan and a point immediately upstream of the slot-like
openings.
5. The drying apparatus as claimed in claim 3 or 4, wherein the
ducting is divided into two separate airflow paths at a point
downstream of the fan.
6. The drying apparatus as claimed in claim 1 or 3, wherein the
width of the or each slot-like opening is no more than 0.5 mm.
7. The drying apparatus as claimed in claim 1 or 3, wherein the fan
is adapted to cause an airflow to be emitted through the or each
slot-like opening at a velocity of at least 80 m/s.
8. The drying apparatus as claimed in claim 7, wherein the fan is
adapted to cause an airflow to be emitted through the slot-like
opening at a velocity of at least 100 m/s.
9. The drying apparatus as claimed in claim 1 or 3, wherein the fan
is adapted to cause an airflow to be emitted through the or each
slot-like opening at a pressure of at least 8 kPa.
10. The drying apparatus as claimed in claim 9, wherein the fan is
adapted to cause an airflow to be emitted through the or each
slot-like opening at a pressure of at least 12 kPa.
11. The drying apparatus as claimed in claim 1 or 3, wherein the
drying apparatus is a hand dryer.
12. (canceled)
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application is a national stage application under 35
USC 371 of International Application No. PCT/GB2006/002144, filed
Jun. 12, 2006, which claims the priority of United Kingdom
Application Nos. 0515739.1, filed Jul. 30, 2005, and 0600880.9,
filed Jan. 17, 2006, the contents of which prior applications are
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to drying apparatus which makes use of
a narrow jet of high velocity, high pressure air to dry an object,
including part of the human body. Particularly, but not
exclusively, the invention relates to a hand dryer in which the air
jet is emitted through a slot-like opening in the casing of the
hand dryer.
BACKGROUND OF THE INVENTION
[0003] The use of air jets to dry hands is well known. Examples of
hand dryers which emit at least one air jet through a slot-like
opening are shown in GB 2249026A, JP 2002-034835A and JP
2002306370A. However, in practice it is very difficult to achieve
an evenly distributed airflow of sufficiently high momentum to dry
the user's hands efficiently in an acceptably short length of time.
The prior art does not achieve this.
SUMMARY OF THE INVENTION
[0004] It is an object of the invention to provide drying apparatus
which, in use, emits an air jet through a slot-like opening which
is capable of drying an object in a short time as compared to the
prior art. It is another object to provide a hand dryer which is
capable of drying the user's hands in a short time in comparison to
the prior art. It is a further object of the invention to provide
an improved hand dryer in which the drying efficiency is improved
in comparison to the prior art.
[0005] A first aspect of the invention provides drying apparatus
having a casing, a cavity formed in the casing for receiving an
object, a fan located in the casing and capable of creating an
airflow, and at least one slot-like opening communicating with the
fan and arranged in the casing so as to direct an airflow
transversely across the cavity, wherein the slot-like opening is
formed between opposing walls which approach one another at an
angle of between 10.degree. and 20.degree..
[0006] In a preferred embodiment, the angle between the walls of
the slot-like opening is substantially 14.degree.. This angle has
been found to be advantageous in that the momentum of the airflow
emitted through the slot-like opening is greatly increased in
comparison to that of the prior art devices. This increases the
efficiency of the dryer by virtue of the fact that more water is
blown from the object during each pass thereof through the airflow
exiting the slot-like openings.
[0007] A second aspect of the invention provides drying apparatus
having a casing, a cavity formed in the casing for receiving an
object, a fan located in the casing and capable of creating an
airflow, and two opposing slot-like openings communicating with the
fan via ducting and arranged in the casing so as to direct an
airflow transversely across the cavity, wherein the ducting has a
first cross-section in the vicinity of the fan whose dimensions are
similar in all directions and a slot-like cross-section in the
vicinity of the openings, the transition between the said
cross-sections being gradual and smooth.
[0008] Preferably, the total cross-sectional area of the ducting is
substantially constant between the fan and a point immediately
upstream of the slot-like openings. This minimises losses within
the ducting and enhances the efficiency of the fan.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] An embodiment of the invention in the form of a hand dryer
will now be described with reference to the accompanying drawings,
in which:
[0010] FIG. 1 is a side view of a hand dryer according to the
invention;
[0011] FIG. 2 is a perspective view of the hand dryer of FIG.
1;
[0012] FIG. 3 is a side sectional view of the hand dryer of FIG.
1;
[0013] FIG. 4 is a side sectional view, shown on an enlarged scale,
of the upper ends of the air ducts forming part of the hand dryer
of FIG. 1;
[0014] FIG. 5 is a schematic sectional side view, shown on a
further enlarged scale, of the slot-like opening located in the
front wall of the cavity of the hand dryer of FIG. 1;
[0015] FIG. 6 is a schematic sectional side view, shown on the same
further enlarged scale, of the slot-like opening located in the
rear wall of the cavity of the hand dryer of FIG. 1;
[0016] FIG. 7 is an isometric view of the ducting forming part of
the hand dryer of FIG. 1 shown in isolation from the other
components of the apparatus;
[0017] FIG. 8a is a plan view of the cavity entrance of a hand
dryer according to a second embodiment of the invention; and
[0018] FIG. 8b is a front view of the slot-like opening located in
the rear wall of the cavity of the hand dryer of FIG. 8a.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Referring firstly to FIGS. 1 and 2, the hand dryer 10 shown
in the drawings comprises an outer casing 12 having a front wall
14, a rear wall 16, an upper face 18 and side walls 20, 22. The
rear wall 16 can incorporate fixing devices (not shown) for
securing the hand dryer 10 to a wall or other structure prior to
use. An electrical connection (not shown) is also provided on the
rear wall or elsewhere on the casing 12. A cavity 30 is formed in
the upper part of the casing 12 as can be seen from FIGS. 1 and 2.
The cavity 30 is open at its upper end and delimited thereat by the
top of the front wall 14 and the front of the upper face 18. The
space between the top of the front wall 14 and the front of the
upper face 18 forms a cavity entrance 32 which is sufficiently wide
to allow a user's hands to be introduced to the cavity 30 through
the cavity entrance 32. The cavity 30 is also open to the sides of
the hand dryer 10 by appropriate shaping of the side walls 20,
22.
[0020] The cavity 30 has a front wall 34 and a rear wall 36 which
delimit the cavity 30 to the front and rear respectively. Located
in the lowermost end of the cavity 30 is a drain 38 which
communicates with a reservoir (not shown) located in the lower part
of the casing 12. The purpose of the drain and reservoir will be
described below.
[0021] As shown in FIG. 3, a motor (not shown) is located inside
the casing 12 and a fan 40, which is driven by the motor, is also
located inside the casing 12. The motor is connected to the
electrical connection and is controlled by a controller 41. The
inlet 42 of the fan 40 communicates with an air inlet 44 formed in
the casing 12. A filter 46 is located in the air passageway
connecting the air inlet 44 to the fan inlet 42 so as to prevent
the ingress of any debris which might cause damage to the motor or
the fan 40. The outlet of the fan 40 communicates with a pair of
air ducts 50, 52 which are located inside the casing 12. The front
air duct 50 is located primarily between the front wall 14 of the
casing 12 and the front wall 34 of the cavity 30, and the rear air
duct 52 is located primarily between the rear wall 16 of the casing
12 and the rear wall 36 of the cavity 30.
[0022] The air ducts 50, 52 are arranged to conduct air from the
fan 40 to a pair of opposed slot-like openings 60, 62 which are
located in the front and rear walls 34, 36 respectively of the
cavity 30. The slot-like openings 60, 62 are arranged at the upper
end of the cavity 30 in the vicinity of the cavity entrance 32. The
slot-like openings 60, 62 are each configured so as to direct an
airflow generally across the cavity entrance 32 towards the
opposite wall of the cavity 30. The slot-like openings 60, 62 are
offset in the vertical direction and angled towards the lowermost
end of the cavity 30.
[0023] FIG. 4 shows the upper ends of the air ducts 50, 52 and the
slot-like openings 60, 62 in greater detail. As can be seen, the
walls 54a, 54b of the air duct 50 converge to form the slot-like
opening 60 and the walls 56a, 56b of the air duct 52 converge to
form the slot-like opening 62. Even greater detail can be seen in
FIGS. 5 and 6. FIG. 5 shows that the slot-like opening 60 has a
width of W1 and FIG. 6 shows that the slot-like opening 62 has a
width of W2. The width W1 of the slot-like opening 60 is smaller
than the width W2 of the slot-like opening 62. The width W1 is 0.3
mm and the width W2 is 0.4 mm.
[0024] Each pair of walls 54a, 54b, 56a, 56b is arranged so that
the respective walls approach one another as they approach the
respective slot-like opening 60, 62. If an imaginary axis 70 is
considered to lie midway between each pair of walls, as is shown in
FIGS. 5 and 6, then each wall 54a, 54b, 56a, 56b lies at an angle
of substantially 7.degree. to the respective axis 70. Thus the
angle formed between each pair of walls 54a, 54b, 56a, 56b is thus
substantially 14.degree.. This angle has been found to be
advantageous, although it could be varied by several degrees.
Angles of between 10.degree. and 20.degree. may be used.
[0025] Sensors 64 are positioned in the front and rear walls 34, 36
of the cavity 30 immediately below the slot-like openings 60, 62.
These sensors 64 detect the presence of a user's hands which are
inserted into the cavity 30 via the cavity entrance 32 and are
arranged to send a signal to the motor when a user's hands are
introduced to the cavity 30. As can be seen from FIGS. 1 and 3, the
walls 54a, 54b, 56a, 56b of the ducts 50, 52 project slightly
beyond the surface of the front and rear walls 34, 36 of the cavity
30. The inward projection of the walls 54a, 54b, 56a, 56b of the
ducts 50, 52 reduces the tendency of the user's hands to be sucked
towards one or other of the walls 34, 36 of the cavity, which
enhances the ease with which the hand dryer 10 can be used. The
positioning of the sensors 64 immediately below the inwardly
projecting walls 54a, 54b, 56a, 56b of the ducts 50, 52 also
reduces the risk of the sensors 64 becoming dirty and
inoperative.
[0026] As can be seen from FIG. 2, the shape of the cavity entrance
32 is such that the front edge 32a is generally straight and
extends laterally across the width of the hand dryer 10. However,
the rear edge 32b has a shape which consists of two curved portions
33 which generally follow the shape of the backs of a pair of human
hands as they are inserted downwardly into the cavity 30 through
the cavity entrance 32. The rear edge 32b of the cavity entrance 32
is substantially symmetrical about the centre line of the hand
dryer 10. The intention of the shaping and dimensioning of the
front and rear edges 32a, 32b of the cavity entrance 32 is that,
when a user's hands are inserted into the cavity 30 through the
cavity entrance 32, the distance from any point on the user's hands
to the nearest slot-like opening is substantially uniform.
[0027] The air ducts 50, 52 form part of the ducting 90 which lies
between the fan 40 and the slot-like openings 60, 62. A perspective
view of the ducting 90 is shown in FIG. 7. The ducting 90 includes
a scroll 92 which lies adjacent the fan 40 and receives the airflow
generated by the fan 40. The scroll 92 communicates with a first
chamber 94 which is generally square in cross-section, although the
cross-section could easily be generally circular. The intention is
that the cross-section of the chamber 94 should have dimensions
which are substantially the same in both directions. Immediately
downstream of the chamber 94 is a Y-junction 96 downstream of which
the air ducts 50, 52 are located. As has been described above, the
air ducts 50, 52 pass towards the upper end of the casing 12 with
the front air duct 50 being located between the front wall 14 of
the casing 12 and the front wall 34 of the cavity 30 and the rear
duct 52 being located between the rear wall 16 of the casing 12 and
the rear wall 36 of the cavity 30. The air ducts 50, 52 communicate
with the slot-like openings 60, 62 at the upper end of the cavity
30.
[0028] The ducting 90 is designed so that the cross-sectional area
of the ducting 90 gradually transforms from the generally square
(or circular) shape of the chamber 94 to the slot-like shape of the
openings in a smooth and gradual manner. Immediately downstream of
the chamber 94, the ducting divides into the air ducts 50, 52, at
the upstream end of which the cross-sectional area is still
generally square in shape--ie, the breadth and depth of the
cross-section are substantially similar. However, the cross-section
changes gradually with distance from the chamber 94 so that the
breadth of each duct 50, 52 increases as the depth reduces. All of
the changes are smooth and gradual to minimise any frictional
losses.
[0029] At a point 98 immediately upstream of each of the slot-like
openings 60, 62, the cross-sectional area of each of the air ducts
60, 62 begins to decrease so as to cause the velocity of the
airflow travelling towards the slot-like openings 60, 62 to
increase dramatically. However, between the chamber 94 and the
point 98 in each air duct 50, 52, the total cross-sectional area of
the ducting (ie. the combined cross-sectional area of the air ducts
50 and 52) remains substantially constant.
[0030] The hand dryer 10 described above operates in the following
manner. When a user's hands are first inserted into the cavity 30
through the cavity entrance 32, the sensors 64 detect the presence
of the user's hands and send a signal to the motor to drive the fan
40. The fan 40 is thus activated and air is drawn into the hand
dryer 10 via the air inlet 44 at a rate of approximately 20 to 40
litres per second and preferably at a rate of least 25 to 27 litres
per second, more preferably air is drawn into the hand dryer 10 at
a rate of 31 to 35 litres per second. The air passes through the
filter 46 and along the fan inlet 42 to the fan 40. The airflow
leaving the fan 40 is divided into two separate airflows; one
passing along the front air duct 50 to the slot-like opening 60 and
the other passing along the rear air duct 52 to the slot-like
opening 62.
[0031] The airflow is ejected from the slot-like openings 60, 62 in
the form of very thin, stratified sheets of high velocity, high
pressure air. As the airflows leave the slot-like openings 60, 62,
the air pressure is at least 15 kPa and preferably approximately 20
to 23 kPa. Furthermore, the speed of the airflow leaving the
slot-like openings 60, 62 is at least 80 m/s and preferably at
least 100 or 150 m/s, more preferably approximately 180 m/s.
Because the size of the slot-like opening 62 located at the end of
the rear duct 52 is greater than the size of the slot-like opening
60 located at the end of the front duct 50, a larger volume of air
is emitted from the duct 52 than from the duct 50. This provides a
greater mass of air for drying the backs of the user's hands which
is advantageous.
[0032] The two thin sheets of stratified, high velocity, high
pressure air are directed towards the surfaces of the user's hands
which, during use, are inserted fully into the cavity 30 and are
subsequently withdrawn from the cavity 30 via the cavity entrance
32. As the user's hands pass into and out of the cavity 30, the
sheets of air blow any existing water off the user's hands. This is
achieved reliably and effectively because of the high momentum of
the air leaving the slot-like openings 60, 62 and because the
airflow is evenly distributed along the length of each slot-like
opening 60, 62.
[0033] Each stratified sheet of air is directed towards the wall of
the cavity 30 which is remote from the slot-like opening through
which the respective sheet of air is emitted. Because the slot-like
openings 60, 62 are also inclined towards the lowermost end of the
cavity 30, the emitted airflows are directed into the cavity 30.
This reduces the risk of turbulent air movement being felt by the
user outside the casing, eg in the user's face.
[0034] It is envisaged that it will take only a small number of
"passes" of the hand dryer described above to dry a user's hands to
a satisfactory degree. (By "pass", we mean a single insertion of
the hands into the cavity and subsequent removal therefrom at a
speed which is not unacceptable to an average user. We envisage
that a single pass will have a duration of no more than 3 seconds.)
The momentum achieved by the airflows is sufficient to remove the
majority of water found on the surface of the user's hands after
washing during a single pass.
[0035] The water removed by the airflows is collected inside the
cavity 30. Each airflow will rapidly lose its momentum once it has
passed the user's hands and the water droplets will fall to the
lower end of the cavity 30 under the forces of gravity whilst the
air exits the cavity 30 either through the cavity entrance 32 or
via the open sides of the cavity 30. The water, however, is
collected by the drain 38 and passed to a reservoir (not shown)
where it is collected for disposal. The reservoir can be emptied
manually if desired.
[0036] Alternatively, the hand dryer 10 can incorporate some form
of water dispersal system including, for example, a heater for
evaporating the collected water into the atmosphere. The means by
which the collected water is dispersed does not form part of the
present invention.
[0037] In an alternative embodiment, the slot-like openings 60, 62
can be arranged so that the sheets of air which are emitted
therefrom are directed generally along planes which are
substantially parallel to one another. This minimises the amount of
turbulent flow present inside the cavity 30 whilst the drying
apparatus is in use.
[0038] In a further alternative embodiment shown in FIGS. 8a and 8b
the slot-like openings are not of constant width across the length
L of the cavity of the hand dryer. FIG. 8a shows a plan view of the
cavity entrance of length L. The dotted lines indicate the position
and shape of the user's hands as they are normally inserted into
the cavity 30 between the front and rear edges 32a, 32b. The arrows
80 shown in FIG. 8a indicate the direction of the airflow emitted
from the slot-like openings 60, 62 located in the edges 32a, 32b of
the cavity entrance 32. In this embodiment the curved portions 33
of the rear edge 32b are symmetrical about the centre line A-A of
the cavity entrance 32 with the centre portion of the rear edge 32b
being closer to the front edge 32a at the centre line than at a
position spaced from the centre line. The minimum distance d
between the front and rear edges 32a, 32b is at the centre line.
The distance between the front edge 32a and the rear edge 32b is at
a maximum, D, at the mid point of each curved portion. FIG. 8b
shows the shape of the slot-like opening located in the rear wall
of the cavity.
[0039] Preferably, the width of the slot-like opening in the rear
wall varies gradually, increasing towards the mid point of the
opening, at centre line A-A of cavity entrance 32.
[0040] In this alternative embodiment it is preferred that the
variation in width of the opening is achieved by varying the
distance of the upper wall of the slot-like opening away from the
lower wall, in the shape of a curve, preferably in a smoothly
curving shape. More preferably the curve is symmetrical about
centre line A-A of the cavity entrance 32. Preferably the maximum
width R of the opening is at centre line A-A and is 0.7 mm.
[0041] Preferably, the width r is substantially constant in regions
F and G with the varying width region (region E in FIGS. 8a and 8b)
comprising at least half the total length L of the cavity entrance,
most preferably the central half. Preferably r is 0.4 mm.
[0042] In region E of the hand dryer the width of the slot-like
opening 62 is greater than the width of the slot-like opening 62 in
regions F and G. The increase in size of the slot-like opening 62
provides a greater mass of air 80 from rear duct 52 for drying the
backs of the user's hands in the thumb and forefinger area which is
advantageous. The greater mass of air in region E and the momentum
achieved by the airflow is sufficient to remove the majority of
water found on the backs of the user's hands after washing during a
single pass.
[0043] The invention is not intended to be limited to the precise
detail of the embodiments described above. Modifications and
variations to the detail which do not alter the scope of the
invention will be apparent to a skilled reader. For example, the
shape of the cavity 30 and its entrance 32 may be altered without
departing from the essence of the present invention.
* * * * *