FILTER FRAME FOR AN AIR HANDLING UNIT

Abstract

A filter frame for an air handling unit, an air handling unit, and a method of assembling a filter frame for an air handling unit. The filter frame (100) includes a holder (110) defining a cavity configured to receive a plurality of filter cells (201, 202; 201, 202, 203), and a removable lid (120) configured to secure the plurality of filter cells (201, 202; 201, 202, 203) in the cavity. The removable lid (120) can also include a biasing element (130) configured to urge the plurality of filter cells (201, 202; 201, 202, 203) together within the cavity, to assist with securing the plurality of filter cells (201, 202; 201, 202, 203) in the cavity.

Claims

1. A filter frame (100) for an air handling unit (300), the filter frame (100) comprising: a holder (110) defining a cavity configured to receive a plurality of filter cells (201, 202; 201, 202, 203); and a removable lid (120) configured to secure the plurality of filter cells (201, 202; 201, 202, 203) in the cavity.

2. A filter frame (100) as claimed in claim 1, wherein the filter frame (100) comprises a biasing element (130) configured to urge the plurality of filter cells (201, 202; 201, 202, 203) together within the cavity.

3. A filter frame (100) as claimed in claim 2, wherein the biasing element is a resiliently biased spring member (130).

4. A filter frame (100) as claimed in claim 2, wherein the removable lid (120) comprises a plurality of biasing elements (130) distributed around a periphery of the removable lid (120).

5. A filter frame (100) as claimed in claim 1, wherein the holder (110) is configured to receive the removable lid (120) at a plurality of positions; wherein a volume of the cavity is defined by the position in which the removable lid (120) is received.

6. A filter frame (100) as claimed in claim 1, wherein the removable lid (120) is configured to be slidably received by the holder (110).

7. A filter frame (100) as claimed in claim 6, wherein the holder (110) comprises a first pair of rails (115); wherein the removable lid (120) comprises a second pair of rails (125); and wherein the holder (110) is configured to receive the removable lid (120) by sliding engagement between the first pair of rails (115) and the second pair of rails (125).

8. A filter frame (100) as claimed in claim 7, wherein a height of the first pair of rails (115) relative to a base (111) of the holder (110) is adjustable from a first height to a second height.

9. A filter frame (100) as claimed in claim 1, wherein the holder (110) comprises a U-shaped body (111, 112, 113).

10. A filter frame (100) as claimed in claim 1, wherein the holder (110) comprises an opening configured to define an air inlet or an air outlet; and wherein the removable lid (120) comprises an opening (128) configured to define the other of the air outlet or air inlet.

11. A filter frame (100) as claimed in claim 1, the filter frame (100) comprising a plurality of filter cells (201, 202; 201, 202, 203) located in the cavity of the filter frame (100).

12. A filter frame (100) as claimed in claim 11, wherein each filter cell (201, 202; 201, 202, 203) contacts one or more adjacent filter cells (201, 202; 201, 202, 203).

13. An air handling unit (300), the air handling unit (300) comprising: a filter frame (100) as claimed in claim 11; and an air pump (350) in flow communication with the filter frame (100) for pumping air through the plurality of filter cells (201, 202; 201, 202, 203).

14. A method of assembling a filter frame (100) for an air handling unit (300), the method comprising: providing a filter frame (100) as claimed in claim 1; providing a plurality of filter cells (201, 202; 201, 202, 203); inserting the plurality of filter cells (201, 202; 201, 202, 203) into the cavity; and mounting the removable lid (120) to the holder (110), such that the plurality of filter cells (201, 202; 201, 202, 203) are held securely within the cavity.

15. A method as claimed in claim 14, wherein the step of mounting the removable lid (120) comprises: sliding the removable lid (120) into the holder (110); and urging the plurality of filter cells (201, 202; 201, 202, 203) together within the cavity using one or more biasing elements (130) of the filter frame (100).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Certain exemplary embodiments of the invention are described below by way of example only and with reference to the accompanying drawings in which:

[0096] FIG. 1A shows a perspective view of a first prior art filter frame;

[0097] FIG. 1B shows a perspective view of a second prior art filter frame;

[0098] FIG. 2A shows a perspective view of a filter frame;

[0099] FIG. 2B shows a perspective view of a filter frame where a lid of the filter frame is partially removed;

[0100] FIG. 3 shows a schematic representation of an exemplary filter cell;

[0101] FIG. 4 shows a cross-sectional side view of a filter frame;

[0102] FIG. 5 shows a side view and a plan view of a resiliently biased spring member;

[0103] FIG. 6 shows a perspective view of a filter frame housed in an air handling unit; and

[0104] FIG. 7 shows a schematic representation of a filter frame housed in an air handling unit.

DETAILED DESCRIPTION OF THE INVENTION

[0105] FIG. 2A and 2B each show a perspective view of a filter frame 100. The filter frame 100 comprises a holder 110 which defines a cavity. The cavity is sized so as to receive a plurality of filter cells 201, 202. The holder 110 also receives a removable lid 120, which secures the plurality of filter cells 201, 202 in the cavity.

[0106] The holder 110 comprises a base 111, a pair of side walls 112 and a back wall 113. The base 111 comprises an opening defining an air inlet (not shown). A front opening is defined between the base 111 and the pair of side walls 112, i.e. opposite the back wall 113. A top opening is defined between the pair of side walls 112 and the back wall 113, i.e. opposite the base 111. As illustrated in FIGS. 2A and 2B, the base 111 is wider than the side walls 112. The portion of the base 111 extending past the side walls 112 may facilitate placement of the filter frame 100 within an air handling unit 300.

[0107] The removable lid 120 is a generally planar structure comprising a central opening 128, the opening 128 defining an air outlet. The opening 128 is bounded by a periphery of the removable lid 120.

[0108] The removable lid 120 and the holder 110 are arranged such that the removable lid 120 is received by the holder 110 at the top opening. When the removable lid 120 is received by the holder 110, as shown in FIG. 2A, the plurality of filter cells 201, 202 are secured in the cavity. The plurality of filter cells 201, 202 are aligned with the air inlet of the holder 110 and the air outlet of the removable lid 120, such that the filter frame 100 defines an air passageway therethrough.

[0109] The plurality of filter cells 201, 202 are inserted into the cavity defined by the holder 110 either by sliding the filter cells 201, 202 into the cavity defined by the holder 110 in a direction as indicated by the arrow in FIG. 2B (i.e. via the front opening of the holder 110); or by placing the filter cells 201, 202 into the cavity from above (i.e. via the top opening of the holder 110).

[0110] FIG. 3 shows a schematic representation of an exemplary filter cell 200. The filter cell 200 comprises a filter cell frame 200a which surrounds a filtering medium 200b, and at least partially defines a boundary, or walls of, the air passageway. The filtering material 200b extends across the air passageway such that all the air passes through the filtering material 200b. As air passes through the filtering material 200b, one or more targeted substances are trapped or absorbed.

[0111] It is preferable to prevent the ingress of objects, debris or targeted substances of greater diameter or size at an upstream location of the air passageway (i.e. towards the air inlet), with targeted substances of diminishing size progressively filtered out as the untreated air flows towards the air outlet through the air passageway. Thus in the present embodiment, the first filter cell 201 is a coarse filter, where the filtering medium 201b is chosen to prevent the ingress of larger targeted substances and/or debris. The second filter cell 202, located downstream of the coarse filter 201, is a HEPA filter, where the filtering medium 202b comprises a pleated structure arranged to absorb particulates. In various embodiments, a carbon filter 203 can be provided downstream of the HEPA filter 202, where the filtering medium 203b of the carbon filter 203 is arranged to absorb odours or other targeted gases.

[0112] When the removable lid 120 is received by the holder 110 as shown in FIG. 2A, the removable lid 120 contacts an upper surface of the filter cell 202 in the cavity and adjacent to the removable lid 120. That is, an underside of the periphery of the removable lid 120 contacts an upper surface of the filter cell frame 202a of the filter cell 202 located adjacent to the removable lid 120. The removable lid 120 therefore secures the plurality of filter cells 201, 202 in place as they are bounded by the removable lid 120, and restrained via frictional forces between the removable lid 120 and the upper surface of the adjacent filter cell 202. Accordingly removal or slippage of the plurality of filter cells 201, 202 via the front opening or the top opening of the holder 110 is restricted when the removable lid 120 is in place.

[0113] The holder 110 comprises a first set of rails 115 and the removable lid 120 comprises a second set of rails 125. The first set of rails 115 and the second set of rails 125 are complementary to one another such that the removable lid 120 can be slidably received by the holder 110, via engagement of the first pair of rails 115 with the second pair of rails 125. The direction of sliding engagement is indicated by the arrow in FIG. 2B. That is, the removable lid 120 is slid towards the back wall 113 of the holder 110 from the front opening of the holder 110.

[0114] As shown more clearly in FIG. 2B, the first pair of rails 115 generally comprises a pair of overturned U-shaped grooves formed by the side walls 112 being bent back on themselves at an uppermost edge. The overturned U-shaped grooves prevent movement of the second pair of rails 125 in an upwards direction. The second pair of rails 125 generally comprises a pair of protrusions which are formed by folding side edges of the periphery perpendicular to the plane of the removable lid 120. When received by the holder 110, the removable lid 120 is effectively sandwiched between the overturned U-shaped grooves of the first pair of rails 115 and the upper surface of the adjacent filter 202 such that an interference fit is produced between the first pair of rails 115 and the second pair of rails 125, which holds the removable lid 120 in place.

[0115] The removable lid 120 comprises a pair of handle members 121 located on adjacent sides of the removable lid 120 perpendicular to the second pair of rails 125. The pair of handle members 121 are therefore located on sides of the removable lid 120 which will be adjacent to the front opening and the back wall 113 of the holder 110. The pair of handle members 121 may facilitate insertion/removal of the removable lid 120 into/from the holder 110. As shown in FIGS. 2A and 2B the removable holder 120 is symmetrical about its lengthwise direction, and accordingly can be inserted into the holder 120 in multiple orientations. This may further facilitate ease of insertion/removal of the removable lid 120 into/from the holder 110.

[0116] FIG. 4 shows a cross-sectional side view of the filter frame 100 comprising the plurality of filter cells 201, 202 received in the cavity. The removable lid 120 is shown received by the holder 110, such that the plurality of filter cells 201, 202 are secured in the cavity. The removable lid 120 comprises a plurality of biasing elements 130, which in the present embodiment are a plurality of resiliently biased spring members, or more specifically are a plurality of C-shaped springs.

[0117] The C-shaped spring is shown in further detail FIG. 5, in both a side view and a plan view. The C-shaped spring 130 comprises a plurality of fastening holes 132, which one or more of may receive a suitable fastening such as a bolt, screw or rivet, to fasten the C-shaped spring to the underside of the removable lid 120. A spring portion 133 is located at a free end distal to the fastening holes 132. The spring portion 133 comprises a curved profile.

[0118] As shown in FIG. 4, each biasing element 130 is attached to an underside of the removable lid 120 and is arranged such that a spring portion 133 of the biasing element 130 contacts the upper surface of the filter cell 202 adjacent to the removable lid 120. Contact with the upper surface of the filter cell 202 deforms the spring portion 133 such that a spring force is generated by the biasing element 130, which in turn urges the plurality of filter cells 201, 202 together within the cavity. The provision of the plurality of biasing elements 130 hence assists the removable lid 120 in securing the plurality of filter cells 201, 202 within the cavity. Further, by urging the plurality of filter cells 201, 202 within the cavity an airtightness of the filter frame 100 may be improved. That is, the plurality of filter cells 201, 202 may be tightly held together due to the urging force provided by the plurality of biasing elements 130 such that no air gaps are present within the air passageway partially defined through the plurality of filter cells 201, 202 and the air inlet, which may otherwise result in untreated air being able to flow through the filter frame 100.

[0119] The direction of the urging force is parallel and opposite to an airflow direction through the air passageway defined partially through the plurality of filter cells 201, 202. Accordingly air currents through the filter frame 100 which, in use, could disturb or move the plurality of filter cells 201, 202 within the cavity are cancelled out or minimised. In other words, the biasing elements 130 are arranged to urge the plurality of filter cells 201, 202 together in a direction opposite to a direction of airflow through the plurality of filter cells 201, 202 when in use.

[0120] The plurality of biasing elements 130 are evenly distributed around the underside of the periphery of the removable lid 120. Evenly distributing the biasing elements 130 may result in an even distribution of force across the upper surface of the adjacent filter 202 (i.e. around the upper surface of the filter cell frame 202a), such that the resulting direction of the urging force is normal to the surface of the removable lid 120. This may further improve air tightness within the filter frame 100.

[0121] As shown in FIG. 4, the biasing elements 130 are located one in each corner of the underside of the removable lid 120, with biasing elements 130 further located evenly between each corner biasing element 130. However, in various embodiments other numbers of biasing elements 130 and distributions of the biasing elements 130 are contemplated.

[0122] Each of the spring portions 133 of the biasing elements 130 is also arranged such that the spring portion 133 guides the biasing element 130 into engagement with the upper surface of the adjacent filter cell 202. That is, the curved or rounded profile of the spring portion 133 provides a smooth contact between the upper surface of the adjacent filter cell 202 and the biasing elements 130. This may facilitate insertion of the removable lid 120 into the holder 110, and also prevent possible damage to the upper surface of the adjacent filter cell 202. Further, as the curved profile of the spring portions 133 is symmetrical, smooth contact between the biasing elements 130 and the upper surface of the adjacent filter cell 202 is provided regardless of the orientation of the removable lid 120 as it is inserted into the holder 110.

[0123] FIG. 6 shows a perspective cross-sectional view of the filter frame 100 housed in an air handling unit 300. As shown schematically in FIG. 7, a pump 350 can be located in flow communication with the air outlet 128 of the filter frame 100, also housed within the air handling unit 300. The pump 350 is hence located downstream of the filter frame 100 such that the pump draws air through the filter frame 100. A direction of airflow through the filter frame 100 is indicated by the arrows F.

[0124] The filter frame 100 is shown comprising three filter cells 201, 202, 203 received within the cavity of the holder 110 however, rather than two filter cells 201, 202. Whilst three filter cells 201, 202, 203 are received within the cavity, the operation of the removable lid 120 and the mechanisms by which the removable lid 120 secures the plurality of filter cells 201, 202, 203 are identical to those described above in respect of the arrangement where two filter cells 201, 202 are received in the cavity.

[0125] To accommodate the third filter cell 203, the filter frame 100 is adjusted from a first position in which the cavity has a first volume (as in FIGS. 2A, 2B and 3) to a second position in which the cavity has a second volume (as in FIG. 6). The second volume is greater than the first volume.

[0126] In the present embodiment the holder 110 comprises a first portion and a second portion. The first portion comprises the base 111, the side walls 112 and the back wall 113. The second portion comprises a pair of side walls 112′ and a back wall 113′ (not visible). The second portion is nested with the first portion, and is slidable with respect to the first portion such that an overall height of the filter frame can be adjusted. That is, the second portion telescopically extends with respect to the first portion. The first portion comprises a plurality of first fastening points to which a secondary fastening point of the second portion can be mated. In the present embodiment the plurality of first fastening points and the second fastening point each comprise a hole through which a threaded member can be received, and a fastener tightened on to, which fastens the holder 110 at the desired height and hence the filter frame 100 in the desired position. In various embodiments, alternative configurations for the plurality of first fastening points and the second fastening point are contemplated.

[0127] It will be appreciated that in each of the first position and the second position, the cross-sectional area of the filter frame 100 remains unchanged. However a height of the holder 110 (and hence a height of the filter frame 100) is increased when the filter frame 100 is adjusted from the first position to the second position. Accordingly the removable lid 120, which is received at the top opening of the holder 110, is capable of being received at a multiplicity of heights or positions with respect to the base 111 of the holder 110.

[0128] Whilst the filter frame 100 has been discussed herein in a preferred orientation where the base 111 of the holder 110 is located at a bottommost part of the filter frame 100 and the removable lid 120 is located at an uppermost part of the filter frame 100, it will be readily appreciated that the filter frame 100 is also capable of being used in alternative orientations. For example, the back wall 113 of the holder 110 may be located at the bottommost part of the filter frame 100 when in use, with the front opening located at the uppermost part of the filter frame 100. In another example, a side wall 112 of the holder 110 is located at the bottommost part of the filter frame 100 when in use, with the opposing side wall 112 located at the uppermost part of the filter frame 100.

[0129] In various embodiments, the first pair of rails 115 may comprise a pair of C-shaped brackets and the second pair of rails 125 may comprise a pair of complementary poles or rods configured to be received by the pair of C-shaped brackets. Other rail configurations are also contemplated in various embodiments.

[0130] In various embodiments, the removable lid 120 is connected to the holder 110 via a hinged connection, preferably at the back wall 113 of the holder 110, in place of the sliding rails 115, 125. In various embodiments the removable lid further comprises a pair of spring-loaded clips or other suitable, hand-releasable, fastenings which are arranged to maintain the hinged connection in a closed position when the plurality of filter cells 201, 202; 201, 202, 203 are located in the cavity. The hand-releasable fastenings are located partially on each of the removable lid 120 and the side walls 112 of the holder 110, and are preferably located distally to the hinged connection.

[0131] In various embodiments, each resiliently biased spring member 130 is formed integral with the removable lid 120, rather than being subsequently attached to the underside of the removable lid 120. Each integrally formed resiliently biased spring member 130 may hence depend from the underside of the removable lid 120 via an integrally formed hinge joint. The integrally formed resiliently biased spring member 130 may be formed for example by laser cutting, or appropriately machining, the resiliently biased spring members 130 from material of the periphery of the removable lid 120.