GB2512043A

GB2512043A - Extractor fan

Info

Publication number: GB2512043A
Application number: GB1303896.3A
Authority: GB
Inventors: Samuel John Gregson
Original assignee: Vent Axia Group Ltd
Current assignee: Vent Axia Group Ltd
Priority date: 2013-03-05
Filing date: 2013-03-05
Publication date: 2014-09-24
Anticipated expiration: 2033-03-05
Also published as: GB2512043B; GB201303896D0

Abstract

An extractor fan comprising a housing 3 fitted in an opening of a building from which air is extracted. Fan 5 comprises a motor 81 driven impeller 71 delivering an air flow through the housing, a flow sensor 97 sensing flow through the housing, and a flow indicator 101, 103, 105 providing an indication of the sensed flow through the housing. The housing may comprise a body 21 including an aperture 23, and a duct 24 extends from the aperture, and a support 28 supporting the fan. The support may comprise a platform 29 coaxial with the duct and a plurality of planar radial web elements 30. A planar cover 7 may be fitted to the body. The impeller may be an axial, radial or hybrid impeller and comprises a hub 77 and a plurality of blades 79. A control unit 91 controls operation of the motor. The sensor may be a velocity or pressure sensor. The indicator may comprise a display 101, a display element 103 (LCD or LED) and an optical element 105 having a reflective surface which may be a right angle prism, or may be a transmitter connected to a wireless handset.

Description

EXTRACTOR FAN

The present invention relates to an extractor fan for a building, particularly, but not exclusively, for residential applications.

In many countries, regulations require the ventilation of buildings and that a minimum prescrIbed volume of air be extracted over a defined period, determining a mInImum flow for the extractor fan. In the UK, these regulations are governed by Building Regulations (Approved Document F).

Furthermore, it is a requirement that building inspectors, in application of the regulations, validate the ventilation as achieved by extractor fans. To date, thIs validation has been done by utilizing test equipment. Whilst this is a long-standing approach, which ensures that an extractor fan achieves the minimum flow, the present inventors have recognized that the test equipment utilized by building inspectors introduces a flow/pressure restrictIon, which requires that the extractor fan is configured to operate at a higher nominal rate, in order to overcome the flow/pressure restriction of the test equipment and still pass the ventilation test. The consequence of requiring the fan to operate at a higher nominal rate is to cause the extractor fan to draw more power than is actually required to achieve the flow as required by regulations.

The present inventors have thus proposed providing an extractor fan with a flow meter and providing for display of a measured flow, without requiring use of any ancillary test equipment which introduces a flow/pressure restriction. In this way, building Inspectors can validate the flow as achieved by an extractor fan, and the need to over-rate the extractor fan is avoided, leading to significant power savings over the operative lifetime of the extractor fan.

In one aspect the present invention provides an extractor fan, comprising a housing which In use is fitted to an opening in a building from which air is to be extracted, a fan assembly which comprises an impeller and a motor unit which is coupled to the impeller to drive the same to deliver an air flow through the housing, a flow sensor for sensing flow through the housing, and a flow indicator for providing an indication of the sensed flow through the housing.

In one embodiment the housing comprises a body member which includes a flow aperture, and a duct which extends from the flow aperture in the body member and defines a flow path for extracted air.

In one embodiment the housing comprises a support for supporting the fan assembly.

In one embodiment the support comprises a platform which is disposed co-axially with the duct, and a plurality of web eiements which extend radially between an outer surface of the platform and an inner surface of the duct.

In one embodiment the web elements comprise substantially planar elements which are disposed in spaced relation around the piatform, optionally being radially directed, and optionally being in substantially parallel relation to a longitudinal axis of the duct.

In one embodiment the housing further comprises a cover which is fitted to the body member.

In one embodiment the cover comprises a cover member which is disposed over and in spaced relation to the body member, such as to define a flow path between the cover member and the body member.

In one embodiment the cover member has a generally planar form, optionally having substantially the same lateral extent as the body member.

In one embodiment the impeller is an axial flow impeller and comprises a hub and a plurality of blades which project radially from the hub.

In one embodiment the hub has a radial dimension which is substantially the same as a radial dimension of the platform of the support, and the blades have a radial projection which corresponds to a radial distance between an outer surface of the platform and an inner surface of the duct of the housing, whereby the blades act to displace air through an annular flow path within the duct.

In one embodIment the extractor fan further comprises a control unit which Is operative to control operation of the fan assembly.

In one embodiment the control unit is implemented on a printed circuit board which is located within a cavity between body parts of the housing, optionally such as to be enclosed from the environment.

In one embodiment the control unit comprises a processor and a motor controller which is operated under control of the processor to control operation of the motor unit to maintain a predefined flow, optionally a predetermined minimum flow, by reference to the sensed flow.

In one embodiment the flow sensor comprises a velocity sensor, which by reference to an open flow area of the housing, enables a determination of flow.

In one embodiment the flow indicator comprises a display which displays indicia which are visible at a normal viewing angle when viewing the fan when installed in the building.

In another embodiment the flow indicator comprises a display which displays indicia which are not visible or at least obscured at a normal viewing angle when viewing the fan when installed in the building. 4-,.

In one embodiment the normal viewing angle Is not more than about 30 degrees from a direction orthogonal to a surface of the building to which the fan is Installed, optionally not more than about 45 degrees, optionally not more than about 60 degrees, optionally not more than about 80 degrees, optionally not more than about 85 degrees.

In one embodiment the display comprises a display element, optionally an LCD or LED element, which displays indicia, and an optical element which extends through an opening in the body member of the housing and relays the displayed indicia.

In one embodiment the optical element is configured to allow displayed indicia to be viewed when the cover is fitted to the housing, but only when viewed laterally of the cover.

In one embodiment the optical element includes a reflective surface which is located over the display element and reflects indicia displayed by the display element laterally relative to the cover, with the reflected indicia being visible in a space between the body member and the cover.

In one embodiment the optical element comprises a right-angle prism, which comprises a main body which closes the opening in the body member and a surface which provides the reflective surface.

In a further embodiment the flow indicator comprises a display, and further comprising a further transparent or at least partially transparent cover which is fitted to the body member during testing and through which the displayed indicia are visible, with this further cover being replaced on completion of testing by the first-mentioned cover.

In one embodiment the display is configured to display indicia only for a predetermined period following connection of the fan to mains voltage. -5.-

In a yet further embodiment the flow Indicator comprises a display which is a part separate to the housing.

In one embodiment the display is provided by a display component which is connected to the housing when a measurement of flow is required, optionally the display component Is plugged into a socket in the housing.

In another embodiment the flow indicator comprises a transmitter, optionally a short-range transmitter, and the display is provided by a wireless handset, optionally by an application running on a smartphone.

In one embodiment the display is configured to display one or more error codes in the event that an obstruction is detected downstream of the housing, such as can occur with improper flwng or as a result of any downstream ducting becoming at least partially blocked.

Preferred embodiments of the present Invention will now be described hereinbelow by way of example only with reference to the accompanyIng drawings, in which: Figure 1 illustrates a front perspective view of an extractor fan In accordance with a preferred embodiment oF the present invention; Figures 2 and 3 illustrate exploded front and rear perspective views of the extractor fan of Figure 1; Figure 4 illustrates a front view of the extractor fan of Figure 1; Figure 5 illustrates a front view of the extractor fan of Figure 1, with the cover removed; Figure 6 illustrates a rear view of the extractor fan of Figure 1; Figure 7 illustrates one side view of the extractor fan of Figure 1; Figure 8 Illustrates the other side view of the extractor fan of Figure 1; Figure 9 illustrates a plan view of the extractor fan of Figure 1; Figure 10 illustrates an underneath view of the extractor fan of Figure 1; Figure 11 Illustrates a sectional view (along section I-I in Figure 3) of the extractor fan of Figure 1; Figure 12 illustrates an enlarged view of detail A In Figure 9; and Figure 13 represents the control circuitry of the extractor fan of Figure 1.

The extractor fan comprises a housing 3 which Is fitted to an aperture in a building, a fan assembly S which is mounted within the housing 3 to draw an air flow therethrough from the building, and a cover 7 which is fitted to the housing 3.

In this embodiment the housing 3 comprises a first, main body part 11 which is fixed to the building, and a second, cover body part 15 which is attached to the first body part 11 and defines a chamber 17 therebetween.

In this embodiment the main body part 11 comprises a body member 21, here in the form a generally rectangular plate, which Includes a flow aperture 23, here located centrally therein, and a duct 24, here a tubular element, having a substantially cylindrical form, which extends rearwardly from the flow aperture 23 in the body member 21 and defines a flow path for ventilated air. When fitted, the body member 21 is located flush to a wall surface and the duct 24 extends through a wall to an external opening, either directly or through further ducting (not illustrated). -.7-

In this embodiment the body member 21 has an internal flange 25 which extends around the periphery of the flow aperture 23 In the body member 4 21 and an external flange 26, here forwardly projecting, which extends around the external periphery of the body member 21 and is configured to F engage a counterpart flange 41 on the cover body part 15, as will be described further hereinbelow.

In this embodiment the main body part 11 comprises a support 28 For supporting the fan assembly 5, here the motor 81 of the fan assembly 5.

In this embodiment the support 28 comprises a platform 29, here of substantially cylindrical form, which Is disposed coaxially with the duct 24, and a plurality of web elements 30 which extend radially between an outer surface of the platform 29 and an inner surface of the duct 24. With this configuration, an annular flow path is defined between the platform 29 and the duct 24, through which ventilated air is expelled.

In this embodIment the web elements 30 comprise substantially planar elements which are disposed In spaced relation around the platform 29, optionally being radially directed, and optionally being in substantially parallel relation to the longitudinal axis of the duct 24.

In this embodiment the duct 24 does not incorporate any back-draught shuttering, but instead the fan assembly 5 is controlled to compensate for any back-draught if and when such arises. k

In this embodiment the cover body part 15 comprises a body member 31, here having a generally planar surface and the same rectangular form as the body member 21 of the main body part 11, which includes a flow aperture 33, here located centrally therein in correspondence with the flow aperture 23 in the body member 21 of the main body part 11, and a coupling 35, here an annular element, having a substantially cylindrical form, which extends rearwardly from the flow aperture 33 in the body member 31 and engages the internal flange 27 at the flow aperture 23 of the body member 21, such that the coupling 35 of the cover body part 15:1 and the duct 24 of the main body part 11 together define a continuous flow path therethrough.

In this embodiment the junction of the body member 31 and the coupling is provided by a radlused surface 37, here having an arcuate surface, whereby an air flow Is drawn over the surface of the body member 31, here in a direction substantially parallel to the wall surface, over the radiused surface 37 and directed orthogonally through the flow channel provided by the coupling 35 of the cover body part 15 and the duct 24 of the main body part 11.

In this embodiment the body member 31 includes an external flange 41, here rearwardly projecting, which extends around the external periphery of the body member 31 and is configured to engage the counterpart flange 26 on the main body part 11.

In this embodiment the body member 31 includes a first opening 45, here adjacent the flow aperture 33 thereof, at which a flow sensor 97 is located, as will be described further hereinbelow.

In this embodiment the body member 31 includes a second opening 47, here adjacent one vertical side thereof, at which an Indication of the flow as achieved through the fan Is displayed, as will be described further hereinbelow.

In this embodiment the body member 31. includes a plurality of fixtures 49, here recesses, which receive counterpart fixtures 65 on the cover 7, as will be described further below.

in this embodiment the cover body part 15 is attached to the main body part ii by fixings 53, here threaded screws, in this embodiment the cover 7 comprises a cover member 61, here generay planar in form.. and having the same rectangular shape as the body member 21 of the main body part 11, in this embodiment the cover 7 includes a plurahtv of Fixtures 65, here projections, which are located in the counterpart fixtures 49 on the body member 31 of the cover body part 15 of the housing 3, and provide fbr fixing of the cover 7 to the housing 3.

In this embodiment the fixtures 65 on the cover 7 comprise clip elements which engage with detents in the counterpart fixtures 49 on the body member 31 of the cover body part 15 ol the housing 3.

In this embodiment the fan assembly 5 comprises an impeller 71 and a motor unit 73 which is coupled to the impeller 71 to drive the same.

in this embodiment the impeller 71 is an axial flow impeiler which comprises a hub 77 and a plurality of blades 79 which project radiafly from the hub 77, here radially outwardly In alternative embodiments the impeller 71 could be a radial flow impeller or a hybrid impeller in this embodiment the hub 77 has a radial dimension which is substantiaHy the same as the radial dimension of the platform 29 of the support 2$, and the blades 79 have a radial projection which corresponds to the radial distance between the outer surface of the platform 29 and the inner surface of the: duct 24 of the housing 3, whereby the blades 79 act to displace air through the annular flow path within the duct 24 in its entirety.

In this embodiment the motor unit 73 comprises a motor 81 and a cradle 83 which receives the motor 81 and fixes the motor 81 to the platform 29 of -10 -the support 28 in the housing 3. For the purposes of IllustratIon, in the exploded views, the motor unit 83 is illustrated to the rear of the duct 24, but in assembly the motor unit 83 Is Installed from the front of the duct 24.

In this embodiment the motor 81 comprises a body 84 and a driven shaft 85, which is coupled to the impeller 71, here directly.

In this embodiment the motor 81 is a brushless motor.

The extractor fan further comprises a control unIt 91 which is operative to control operation of the fan, In thIs embodiment through control of the motor 81.

In this embodiment the control unit 91, which implemented on a printed circuit board 93, is located within the cavity between the body parts 11, 15 of the housing 3. In this way, the control unit 91 is enclosed from the environment, which is typically humid or wet.

In thIs embodiment the control unit 91 comprises a processor 94 and a motor controller 95 which is operated under control of the processor 94 to control operation of the motor 81 to maintain a predefined flow by reference to a sensed flow. With this arrangement, power consumption is minimIzed, as the motor 81 is only being driven sufficiently to achieve the predefined flow, and not a greater flow.

In this embodiment the motor controller 95 is controlled by the processor 94 to maintain a predefined flow, and, in the event of a back-draught through the duct 24, the motor 81. is driven faster to compensate for this back-draught.

In this embodiment the control unit 91 Includes a flow sensor 97 which detects flow through the fan.

-11 -In this embodiment the flow sensor 97 comprIses a velocity sensor, here a MEMS sensor, which by reference to the known open flow area of the fan, enables a determination of flow rate by the processor 94.

In another embodiment the flow sensor 97 could comprise a pressure sensor, here a MEMS sensor, which, by reference to a (low table enables a determInation of flow rate by the processor 94.

In this embodiment the control unIt 91 further comprises a display 101 which is configured to dIsplay a flow characteristic, here flow rate. In this way, the flow beIng achieved by the fan can be checked. This is particularly advantageous in relation compliance with regulations and validation by building inspectors, as a building inspector can validate the flow being achieved without the application of testing equipment, which the present inventors have found to alter the flow characteristics of the fan and require over-rating of the fan in normal operation.

In this embodiment the display 101 comprises a display element 103, such as an LCD or LED element, which is fixed to the PCB 93 and an optical element 105 which extends through the second opening 47 in the body member 31 of the cover body part 15.

In this embodiment the optical element 105 is configured to allow the display 101 to be viewed when the cover 7 is fitted to the housing 5, but not from the front of the fan.

In this embodiment the optical element 105 comprises a reflector 106, which is located over the display element 103 and reflects indicia displayed by the display element 103 laterally relative to the front surface of the fan, such that the indicia can only be observed when viewed close to the surface of the wall on which the fan is mounted, with the reflected indicia being visible In the space between the housing 3 and the cover 7.

-12 -In this embodiment the optical element 105 comprises a right-angle prism, the main body of which closes the second opening 47 in the cover body part of the housing 3 and one surface of which provides the reflector 106.

In an alternative element the reflector 106 could be provided by a separate reflective surface, which could, for example, be attached to a rear surface of the cover 7. In one such embodiment the second opening 47 in the cover body part 15 of the housing 3 could be closed by a transparent window.

In an alternative embodiment the optical element 105 could be omitted and a separate transparent or at least partially transparent cover member 7 provided In order to allow for testing, with this cover member 7 being replaced on completion of testing.

In an alternative embodiment the display 101 could be provided by a part separate to the fan.

In one embodiment the display 101 could be provided by a component which Is connected to the control unit 91 of the fan when a measurement of flow is required, such as a component which is plugged into a socket provided in a side of the housing 3.

In yet another embodiment the control unit 91 could, in addition to or in replacement of the dIsplay 101, be provided with a transmitter, typically a short-range transmitter, such as a Bluetooth (RTM) transmitter, and the measurement provided on a wireless handset. In one embodiment the wireless handset could be provided by an application running on a smartphone.

In a preferred embodiment the display 101 is concealed or at least obscured from a normal viewing angle, such as not more than about 30 degrees from a direction orthogonal to the building surface to whIch the fan is mounted, preferably not more than about 45 degrees, more preferably not more than -13 -about 60 degrees, yet more preferably not more than about 80 degrees, still more preferably not more than about 85 degrees.

In this embodiment the control unit 91 Is configured to power the display 101 for a predetermined period following connection of the fan to the mains. In one embodiment the display 101 is powered for 5 minutes, but the display 101 could be powered for any requIred period. If, at any time, it Is required to identify the flow, the fan can be disconnected and re-connected to mains voltage, typically by breaking the fuse link at the consumer unit.

In one embodiment the control unit 91 can be configured to drive the display 101 to display a system pressure. Knowledge of this system pressure in conjunction with the system design, such as having a long or short length of downstream ducting, enables a determination as to whether there is a fault, as could occur with Improper installation or as a result of any downstream ducting becoming at least partially blocked.

In this embodiment the motor controller 95 operates under a control algorithm which is configured to minimize noise generated by operation of the motor 81.

Finally, it will be understood that the present invention has been described in its preferred embodiments and can be modified in many different ways with departing from the scope of the invention as defined by the appended claims.

Claims

CLAIMS1. An extractor fan, comprising a housing which in use is fitted to an opening in a building from which air is to be extracted, a fan assembly which comprises an impeHer and a motor unit which is coupled to the impeUer to drive the same to deliver an air flow through the housing, a flow sensor for sensing flow through the housing, and a flow indicator for providing an indication of the sensed flow through the housing.
2 The extractor fan of claim 1, wherein the housing comprises a body member which includes a flow aperture, and a duct which extends from the flow aperture in the body member anrJ define.s a flow path for extracted air,
3. The extractor fan of caim 2, wherein the housing comprises a support [or supporting the fan assembly.
4. The extractor fan of claim 3, wherein the support comprises a pla&orm whri s ospoed co axially Mth hu cjct, and a plur of web elements which extend radially between an outer surface of*Le platform and an inner surface of the duct.
5, The extractor fan of ciaim 4, wherein the web elements comprise subrtantiaily planar elements which are. disposed in spaced relation around the piatforrn, optionafly being radiafly directed, and optionally being in suhstan.tiaUy earaHel relation to a longitudinal axis of the di i' -LA %_.
6. The extractor fan of any of claims 2 to 5, wherein the housing further comprises a cover which is fitted to the body member.-15 -
7. The extractor fan of claim 6, wherein the cover comprises a cover member which is disposed over and in spaced relation to the body member, such as to define a flow path between the cover member and the body member.
8. The extractor fan of claim 7, wherein the cover member has a generally planar form, optionally having substantially the same lateral extent as the body member.
9. The extractor fan of any of claims 1 to 8, wherein the impeller is an axial flow impeller and comprises a hub and a plurality of blades which project radially from the hub.
10. The extractor fan of claim 9, wherein the hub has a radial dimension which is substantially the same as a radial dimension of the platform of the support, and the blades have a radial projection which corresponds to a radial distance between an outer surface of the platform and an inner surface of the duct of the housing, whereby the blades act to displace air through an annular flow path within the duct.
11. The extractor fan of any of claims 1 to 10, further comprising a control unit which is operative to control operation of the fan assembly.
12. The extractor fan of claim 11, wherein the control unit is implemented on a printed circuit board which is located within a cavity between body parts of the housing, optionally such as to be enclosed from the environment.
13. The extractor fan of claim 12, wherein the control unit comprises a processor and a motor controller which is operated under control of the processor to control operation of the motor unit to maintain a -16 predefined flow, optionally a predetermined minimum flow, by reference to the sensed flow.
14. The extractor fan of any of claims 1 to 13, wherein the flow sensor comprises a velocity sensor, which by reference to an open flow area of the housing, enables a determination of flow.
15. The extractor fan of any of claims 1 to 14, wherein the flow Indicator comprises a display which displays indicia which are visible at a normal viewing angle when viewing the fan when Installed in the building.
16. The extractor fan of any of claims 1 to 14, wherein the flow indicator comprises a display which displays Indicia which are not visible or at least obscured at a normal viewing angle when viewing the fan when installed in the building.
17. The extractor fan of claim 15 or 16, wherein the normal viewing angle is not more than about 30 degrees from a direction orthogonal to a surface of the building to which the fan is installed, optionally not more than about 45 degrees, optionally not more than about 60 degrees, optionally not more than about 80 degrees, optionally not more than about 85 degrees.
18. The extractor fan of any of claims 15 to 17, wherein the display comprises a display element, optionally an LCD or LED element, which displays indicia, and an optical element which extends through an opening in the body member of the housing and relays the displayed indicia.
19. The extractor fan of claim 18, wherein the optical element is configured to allow displayed indicia to be viewed when the cover is fitted to the housing, but only when viewed laterally of the cover.-17 -
20. The extractor fan of claim 18 or 19, wherein the optical element includes a reflective surface which Is located over the display element and reflects indicia displayed by the display element laterally relative to the cover, with the reflected indicia being visible in a space between the body member and the cover.
21. The extractor fan of claim 20, wherein the optical element comprises a right-angle prism, which comprises a main body which closes the opening in the body member and a surface which provides the reflective surface.
22. The extractor fan of any of claims 1 to 14, wherein the flow indicator comprises a display, and further comprising a further transparent or at least partially transparent cover which is fitted to the body member during testing and through which the displayed indicla are visible, with this further cover being repiaced on completion of testing by the first-mentioned coven
23. The extractor fan of any of claims 1 to 22, where the display is configured to display indicia only for a predetermined period following connection of the fan to mains voltage.
24. The extractor fan of any of claims 1 to 14, where the flow indicator comprises a dlspiay which is a part separate to the housing.
25. The extractor fan of claim 24, wherein the display is provided by a display component which is connected to the housing when a measurement of flow is required, optionally the display component is plugged into a socket in the housing.
26. The extractor fan of claim 24, wherein the flow indicator comprises a transmitter, optionally a short-range transmitter, and the display is -18 -provided by a wireless handset, optionally by an application running on a smartphone.
27. The extractor fan of any of claims 15 to 26, whereIn the display is configured to dIsplay one or more error codes In the event that an obstruction is detected downstream of the housing, such as can occur with improper fitting or as a result of any downstream ducting becoming at least partially blocked.
28. An extractor fan substantially as hereinbefore described with reference to the accompanying drawings.