U.S. patent application number 10/588069 was filed with the patent office on 2007-11-01 for electric fan.
This patent application is currently assigned to Farmer Controls PLc. Invention is credited to Ronald Kenneth Russell.
Application Number | 20070253806 10/588069 |
Document ID | / |
Family ID | 34828673 |
Filed Date | 2007-11-01 |
United States Patent
Application |
20070253806 |
Kind Code |
A1 |
Russell; Ronald Kenneth |
November 1, 2007 |
Electric Fan
Abstract
This invention relates to electric fans or blowers which may be
used in, for instance, domestic, medical, commercial, industrial
and transport applications.
Inventors: |
Russell; Ronald Kenneth;
(Swindon, GB) |
Correspondence
Address: |
SHUMAKER & SIEFFERT, P. A.
1625 RADIO DRIVE
SUITE 300
WOODBURY
MN
55125
US
|
Assignee: |
Farmer Controls PLc
Envirovent House Hornbeam Business Park Harrogate
North Yorkshire
GB
HG2 8PA
|
Family ID: |
34828673 |
Appl. No.: |
10/588069 |
Filed: |
January 28, 2005 |
PCT Filed: |
January 28, 2005 |
PCT NO: |
PCT/GB05/00307 |
371 Date: |
April 23, 2007 |
Current U.S.
Class: |
415/15 ;
415/121.2; 415/208.2; 416/247R |
Current CPC
Class: |
F04D 29/4253 20130101;
F04D 29/703 20130101; F04D 29/263 20130101; F04D 27/008
20130101 |
Class at
Publication: |
415/015 ;
415/121.2; 415/208.2; 416/247.00R |
International
Class: |
F04D 29/70 20060101
F04D029/70 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 30, 2004 |
GB |
0402041 8 |
Jun 15, 2004 |
GB |
0413332 8 |
Claims
1. An electric fan comprising a housing body, a front cover
defining a fluid inlet to the housing and a rear fluid outlet
aligned with said fluid inlet, a motor and impeller mounted within
the housing between said inlet and outlet for drawing fluid into
the housing in a direction from said inlet towards said outlet
within the housing in an outwardly radially direction before
exiting via the outlet, the front cover being moveable relative to
the housing to allow access to the impeller and motor.
2. An electric fan according to claim 1, wherein the front cover is
removable from the housing body.
3. An electric fan according to claim 1 or 2, wherein the removal
of the front cover effects isolation of the motor to prevent the
fan working in an unguarded state.
4. An electric fan according to any of claims 1 to 3, wherein the
front cover clips onto the housing body about their respective
peripheral edges.
5. An electric fan according to any of claims 1 or 4, wherein the
impeller is removable from the housing body
6. An electric fan according to any of claims 1 to 5, wherein
components of the electric fan are co-axially arranged along the
axis such that removal of a first component by movement along the
axis facilitates access to a second component.
7. An electric fan according to any of claims 1 to 6 which further
includes a means to collect the radially directed fluid and direct
it towards the fluid outlet, the collecting means being a plurality
of collection chambers.
8. An electric fan according to claim 7, wherein the collection
chambers are circumferentially spaced about said axis.
9. An electric fan according to claim 8 or 9, wherein the
collection chambers comprise a plurality of helical conduits.
10. An electric fan according to claim 9, wherein the helical
conduits each have a circumferentially disposed inlet and an
axially disposed outlet.
11. An electric fan according to any of claims 1 to 10, wherein at
least one component of the fan is substantially sealed from dust or
water.
12. An electric fan according to claim 11, wherein the component is
selected from the group consisting of; motor, drive, controls.
13. An electric fan according to claims 11 or 12, wherein the
sealed component is encased in protective chamber.
14. An electric fan according to any of claims 1 to 13, wherein the
fan further comprises a humidity sensor.
15. An electric fan according to claim 14, wherein the speed of the
fan is increased in response to a predetermined increase in
humidity detected by the humidity sensor.
16. An electric fan according to any of claims 1 to 15, wherein the
fluid is a gas.
17. An electric fan according to claim 16, wherein the gas is
air.
18. An electric fan according to any of claims 1 to 15, wherein the
fan is a pump and the fluid is a liquid.
19. An electric fan according to any of claims 1 to 18, wherein the
fan is an extract fan, pressure device or circulation device.
20. A fan assembly comprising two or more electric fans according
to any of claims 1 to 19, wherein the fans are mounted within a
common housing.
21. An appliance comprising an electric fan according to any of
claims 1 to 19.
22. An appliance according to claim 21, wherein the appliance is a
domestic appliance.
Description
FIELD OF THE INVENTION
[0001] This invention relates to electric fans or blowers which may
be used in, for instance, domestic, medical, commercial, industrial
and transport applications.
[0002] Reference will be made hereinbelow to ventilating fans for
causing air to be expelled from a space, for instance, from a
kitchen. Such fans may be wall, window or duct mounted so that the
air is expelled from the kitchen or other space to the exterior of
the building. However, it should be appreciated that the present
invention may be embodied in all sorts of different pressure and
suction fans and blowers and, more generally, to fluid moving
devices, for example circulation devices, in which the fluid is a
gas or a liquid.
BACKGROUND TO THE INVENTION
[0003] Ventilating fans are known which may be of the centrifugal
or axial variety. In general, they are rather inefficient devices
and there is a need for a ventilating fan which can effectively
shift large volumes of air with low electric power requirements.
Existing fans have components such as a motor, electronics and
connectors, that, because they are positioned in the path of air
passing through the fan, are vulnerable to dust, grease and other
contaminants. These contaminants cause reduction in life expectancy
of the components and make them difficult to clean.
[0004] An attempt to deal with these problems involves the
provision of some form of device to pre-filter the air and such a
device adds to the cost of the fan and itself has maintenance
requirements.
[0005] Accordingly, there is a need for a ventilating fan which can
be easily disassembled, at least to the extent that its front cover
may be removed to allow the consequential easy removal of the
various moving parts, for instance, the impeller. Once these moving
parts are removed, smooth, rounded internal surfaces are more
easily cleaned.
STATEMENTS OF THE INVENTION
[0006] According to the present invention there is provided an
electric fan comprising a housing body, a front cover defining a
fluid inlet to the housing and a rear fluid outlet aligned with
said fluid inlet, a motor and an impeller mounted within the
housing between said inlet and outlet for drawing fluid into the
housing in a direction from said inlet towards said outlet in an
outwardly radially direction before exiting via the outlet, the
front cover being moveable relative to the housing to allow access
to said impeller and motor.
[0007] The fact that the front cover is moveable relative to the
housing body enables easy access to the components of the fan for
servicing and cleaning purposes. The front cover may, for example,
be hinged to a wall of the housing body.
[0008] In a more preferred embodiment of the invention the front
cover is removable. For example, the front cover is attached to the
housing by screws or a snap fit-mechanism or is slidable relative
to the housing body. Even more preferably the front cover clips
onto the housing body about their peripheral edges.
[0009] In order to increase the safety aspect of the fan the
movement of the front cover effects isolation of the motor and thus
ensures that it is not possible to run the electric fan in an
unguarded state.
[0010] Once the front cover has been moved or removed to allow
access to other components within the fan, such as the impeller,
hub, motor mount, air collector, driver or duct adapter, these
components can be simply cleaned in situ using an appropriate
cleaning solution, for example warm soapy water.
[0011] In an even more preferred embodiment of the invention the
impeller is removable from the electric fan and can be thoroughly
cleaned by immersion in an appropriate cleaning solution, for
example water soapy water. This avoids the problem of unsightly
fans with clogged filters. Preferably the impeller is removable
from the housing by relative movement along the axis between the
fluid inlet and the fluid outlet.
[0012] Any un-removable components exposed within the fan by the
removal of the front cover and/or impeller are preferably designed
and arranged such that plain surfaces are exposed allowing easy
cleaning with, for instance, a damp cloth. Furthermore such
components, for example, the motor, the drive and the controls, are
preferably sealed from dust and water spray, which makes them not
only easy to clean but also both hygienic and safe. Accordingly, a
fan of the present invention may have all those components which
are vulnerable to contamination by dust, grease and other
contaminants, encased in protective chambers, thereby avoiding the
problems mentioned above in connection with existing electric fans.
Cleaning is fundamentally easier and quicker and life expectancy is
extended. Furthermore, the requirement for a device to pre-filter
the air is eliminated.
[0013] In a further preferred embodiment of the invention the
components of the fan are co-axially arranged along an axis
extending between the fluid inlet and the fluid outlet such that
removal of a first component by movement along the axis facilitates
access to a second component. For example, removal of the front
cover enables access to the impeller, removal of the impeller
enables access to the motor mount, removal of the motor mount
enables access to the motor and so on.
[0014] In an alternative embodiment of the invention the components
of the electric fan are concentrically arranged along the axis.
[0015] In a still further preferred embodiment of the invention
which further includes a means to collect the radially directed
fluid and direct it towards the fluid outlet, the collecting means
being a plurality of collection chambers.
[0016] Preferably the collection chambers are circumferentially
spaced about said axis. Preferably, the collecting means is a
plurality of helical conduits, each having a circumferentially
disposed inlet and axially disposed outlet.
[0017] The provision of multiple collecting chambers to receive air
from a rotating impeller allows significant reductions in space for
a given performance, and without reduction in efficiency, compared
with a conventional fan.
[0018] In a preferred embodiment of the present invention, the fan
is provided with a humidity sensor and means for automatically
increasing the speed of the fan in response to a predetermined
increase in the humidity of the fluid passing through the fan.
[0019] The inclusion of a humidity sensor in a fan of the present
invention allows the fan to be responsive very rapidly to a
situation requiring effective operation of the fan. Such situations
may include the running of a bath or shower in a bathroom or the
cooking of a meal in a kitchen. The fan can be running at a
relatively low speed (standby operation) with a very small flow
rate passing through it. As and when the humidity sensor detects a
sufficient increase in the humidity of the air passing through the
fan, the speed of the fan may be automatically increased. In this
way the fan will be "in control" of the local environment at all
times. As soon as any increase in local humidity is dealt with, the
fan will quickly and automatically revert to standby mode.
[0020] If the "non-local" environment is itself both warm and
humid, the above described system, incorporating a humidity sensor,
would result in the fan continuing to operate at an increased flow
rate. To deal with the situation, an "outside" humidity sensor can
also be installed along with appropriate circuitry to compare
humidity both "locally" and "non-locally".
[0021] A fan in accordance with the present invention may be one
which can operate at two speeds, a low speed or trickle mode and a
higher speed or boost mode. When fitted with a humidity sensor as
described above, the fan may be provided with a variable speed
function to match the rising or falling humidity. The above
described fans are provided with a housing body or rear car case
which is an easy to fit, maintenance-free item which never needs to
be removed from the wall to which it is secured. A fan in
accordance with the present invention may be small enough for
bathroom installations but with more than enough power for
kitchens. Small power consumption is achieved through the use of a
self-regulating, whisper-quiet, DC electronically commutated motor.
The fan is filterless. The internal design gives air management
which forces dust and contaminates away from the sealed electric
motor, pushing it past internal smooth surfaces to the atmosphere,
thereby avoiding the need for a filter. As the motor is protected
from noise-inducing, power-draining dirt and grime, it remains
quiet, efficient and economical throughout its life.
[0022] At the heart of the fan is located the above described
helical power expansion chamber which moves large volumes of
vapour-laden and/or contaminated air, all within the confines of a
small piece of equipment operating with great power efficiency.
[0023] It will be understood that the electric fan of the present
invention can be an extract fan, pressure device or circulation
device. Preferably the fluid is air.
[0024] In an alternative embodiment of the invention the electric
fan is a pump for a liquid.
[0025] There is also provided a fan assembly comprising two or more
electric fans according the invention wherein the fans are mounted
within a common housing.
[0026] There is also provided an appliance comprising an electric
fan according to the invention, for example a domestic
appliance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The invention is illustrated, by way of example only, by the
embodiments shown in the accompanying drawings, in which:
[0028] FIG. 1 is a front view of an electric fan in accordance with
the present invention;
[0029] FIG. 2 is a side view of the electric fan of FIG. 1;
[0030] FIG. 3 is a section on line AA of FIG. 1;
[0031] FIG. 4 is a section on line BB of FIG. 1;
[0032] FIG. 5 is a rear view of the fan of FIG. 1;
[0033] FIG. 6 is an exploded perspective view of the fan of FIG. 1;
and
[0034] FIG. 7 is a scrap assembly showing part of an electric fan
similar to that of FIG. 1 and incorporating a humidity sensor.
DETAILED DESCRIPTION OF THE INVENTION
[0035] The invention will now be described, by way of example, with
reference to the accompanying drawings.
[0036] An electric fan 1 is broadly rectangular when viewed from
the front or the rear as shown in FIGS. 1 and 5. From the side it
is again generally rectangular although with a somewhat protruding
front face 3 and a rear extension 5 provided by a duct adaptor
7.
[0037] The main components of fan 1 are perhaps best illustrated in
the exploded view of FIG. 6, these components being front cover 9,
impeller 11, hub 13, motor mount 15, motor 17, air collector 19,
housing body 21 and the above mentioned duct adaptor 7. These
components are all connected together essentially concentrically
along an axis extending between the front cover 9 and the duct
adaptor 7.
[0038] Front cover 9 includes a centrally disposed circular air
inlet which itself has a central hub 25 surrounded by concentric
rings 27, interlinked by generally radial webs 29.
[0039] Front cover 9 clips on to housing body 21 about their
respective peripheral edges. Housing body 21 is in the form of a
deep, generally rectangular wall 31 which is partly open at both
ends, the front end being for securing to front cover 9 and the
rear end for securing to duct adaptor 7. Within walls 31, air
collector 19 is provided with a lead cover 5 which encloses the
electric leads.
[0040] Together the front cover 9 and housing body 21 provide the
overall housing for the electric fan 1. Within the housing the
various components 11, 13, 15, 17 and 19 are located and extending
rearwardly from the housing is the duct adaptor 7.
[0041] Considering the components within the housing from front to
rear, impeller 11 has a central hub connector 33 which includes a
fastening device for securing the impeller to adjacent hub 13. This
fastening device (not shown) is released by gripping radially
outwardly biased lugs 35 and pressing inwardly towards the centre
of the hub connector 33.
[0042] Surrounding hub connector 33 are axially spaced apart
forward and rearward rings 37 and 39. Between these rings extend
peripherally spaced apart vanes 41, each vane being attached at
each end to a respective ring 37, 39 and extending generally
towards the centre of the impeller. Each vane 41 is broadly an
elongate rectangle being curved across its width.
[0043] Hub 13 is generally of truncated dome shape having a
flattened forward end 43 from the middle of which projects a
circular peg 45. On opposite sides of peg 45 are apertures 47 and
these, together with peg 45, are for engagement with corresponding
elements (not shown) of the fastening device located within the
central hub connector 33 of impeller 11.
[0044] The inner surface of rearward rim 49 and forward circular
flange 51 of motor mount 15 form a labyrinth seal between the
moving and stationary components of the fan.
[0045] Motor mount 15 is in the form of a cup within which is
located the forward end of motor 17. Motor 17 is provided with a
forwardly extending stub shaft 53 which extends through motor mount
15 to locate in the hollow peg 45 as best illustrated in FIG. 4.
When the motor is running, stub shaft 53 rotates and this in turn
causes hub 3 and impeller 11 to rotate.
[0046] The rotation of impeller 11 causes air to be sucked into the
housing of fan 1 through the inlet provided in front cover 9.
Surrounding the above described components 11, 13, 15 and 17 is an
inner housing in the form of an air collector 19. In this
embodiment, collector 19 comprises two air collection
ducts/conduits 55a and 55b (55b is not shown) each of which are
substantially helically shaped channels which extend both
circumferentially and rearwardly from the front of the collector 19
towards its rear. The orientation of the helical channel of air
collection duct 55a is such that it directs air in a clockwise
direction towards a peripherally located discharge 57a at the rear.
The orientation of the helical channel of air collection duct 55b
is such that it directs air in an anti-clockwise direction towards
a peripherally located discharge 57b (not shown) at the rear. This
air collector 19 accordingly directs air thrown radially outwardly
by impeller 11 in a direction towards the rear of the fan and into
duct adaptor 7. In use duct adaptor 7 will extend through a window
or wall to the exterior of the building or may itself be fitted to
a further conduit which extends to the exterior of the building. It
may also be fitted in a duct in, for instance, a roof, ceiling or
floor cavity. Appropriate circuitry and electronic components
necessary to work the motor of the electric fan are provided on a
circuit board that is located within a cavity (not shown) that is
provided in the lower section of the rear of collector 19.
[0047] The internal housing of the above described electric fan
collects the air discharging from impeller 11 and, in so doing,
causes the air to expand thereby converting part of the kinetic
pressure head to a static head. The extent to which such a
conversion occurs depends on the system to which the blower is
subjected, the system being the arrangement located either before
the inlet to the device, or after its outlet or a combination of
both. The level and efficiency of this conversion directly
contributes to the capacity and overall efficiency of the fan as a
whole.
[0048] Essentially the above described fan receives air travelling
in the direction of the main axis of the device and, through the
rotating part of the device, causes it to leave in a radial
direction. The air leaves via a collecting chamber which modifies
the static and dynamic components of pressure and provides a
discrete ducted direction to the air. The provision of multiple
collecting chambers to receive air from a single rotating impeller,
as provided by the above described fan, allows significant
reductions in space for a given performance and without reduction
in efficiency. In addition, with many smaller outlets from the
multiple collecting chambers, changing the direction of the air to
the axial directions is achieved much more efficiently.
[0049] The location of the key moving and other parts of the above
described fan around a single axis extending from the front to the
rear of the device allows for the simple disassembly of at least
some of these key components. This is particularly advantageous in
that it allows the fan to be very simply maintained, in particular
with regard to removing grease, cleaning generally, washing and
disinfecting.
[0050] Referring now to FIG. 7 of the accompanying drawings, there
is illustrated the central part of a fan similar to that described
above. Items corresponding to those already mentioned in connection
with the fan described above have been indicated with the same
reference numerals. The airflow leading to discharge from the fan
via duct adaptor 7 has been indicated by arrows 59. Located on the
outer surface of an internal partition 61 of collector 19 is a
humidity sensor 58. Provided adjacent and forward of humidity
sensor 58 is a hole 63 in motor mount 15. Opposite hole 63 and
provided in the wall of collector 19, adjacent and rearward of
sensor 58, is a further hole 65 which is aligned with hole 63.
Arrows 67 indicate the airflow through holes 65 and 63, from the
main airflow indicated by arrows 59, and past and into contact with
sensor 58.
* * * * *