AIR FILTER ASSEMBLY WITH IMPROVED LIQUID DRAINAGE

Abstract

An air filter assembly and use thereof for filtration of air in wet or damp conditions, said air filter assembly comprising: an air filter comprising a front frame defining at least one rectangular aperture for receiving an air flow to be filtered; characterized in that said air filter assembly comprises a deflector element extending alongside edge portion of the rectangular aperture and adapted an to deflect an air flow passing through the rectangular aperture away from an adjacent inside surface of the air filter; and a liquid drain arranged such that liquid collected at said adjacent inside surface of the air filter can exit the air filter through said liquid drain.

Claims

1. An air filter assembly comprising: an air filter comprising a front frame defining at least one rectangular aperture for receiving an air flow to be filtered; characterized in that said air filter assembly comprises a deflector element extending alongside an edge portion of the rectangular aperture and adapted to deflect an air flow passing through the rectangular aperture away from an adjacent inside surface of the air filter; and a liquid drain arranged such that liquid collected at said adjacent inside surface of the air filter can exit the air filter through said liquid drain.

2. An air filter assembly according to claim 1, wherein said liquid drain is arranged between said deflector element and said edge portion of the rectangular aperture, such that liquid collected at said adjacent inside surface of the air filter can exit the air filter through said liquid drain.

3. An air filter assembly according to any one of claim 1 or 2, wherein said air filter is a panel filter, a deep pleat box filter, or a V-type filter.

4. An air filter assembly according to any one of claims 1-3, wherein said air filter is a panel filter or a deep pleat box filter comprising: a rectangular pleated filter element; and a rectangular filter frame having the pleated filter element disposed therein, said filter frame comprising a first pair of opposing side plates sealed to the pleated edges of the rectangular pleated filter element and a second pair of opposing side plates sealed to the non-pleated edges of the rectangular pleated filter element, said rectangular filter frame forming a front frame defining a rectangular aperture at the open end for receiving an air flow to be filtered.

5. An air filter assembly according to any one of claims 1-3, wherein said air filter is a V-type filter comprising: at least one pair of rectangular pleated filter elements arranged in a V configuration having an open end, a closed end and two V-shaped ends; and a filter frame having the at least one pair of filter elements disposed therein, said filter frame comprising a front frame sealed to the filter elements at the open end, a rear plate sealed to the filter elements at the closed end, and two side plates connected to the front and rear plates and sealed to the filter elements at the V-shaped ends; said front frame defining at least one rectangular aperture at the open end for receiving an air flow to be filtered.

6. An air filter assembly according to any one of the preceding claims, wherein the deflector element extends in a direction substantially perpendicular to the pleat direction of the filter element(s).

7. An air filter assembly according to any one of the preceding claims, wherein said at least one rectangular aperture for receiving an air flow to be filtered has two opposing short sides and two opposing long sides and said deflector element extends alongside an edge portion of a short side of the rectangular aperture.

8. An air filter assembly according to any one of the preceding claims, wherein in a normal operating mode: said at least one rectangular aperture for receiving an air flow to be filtered is vertical; said deflector element extends alongside a bottom edge portion of the rectangular aperture; and said adjacent inside surface of the air filter is a bottom inside surface.

9. An air filter assembly according to any one of the preceding claims, wherein the pleated edges of the rectangular pleated filter element(s) are sealed to the side plates.

10. An air filter assembly according to any one of the preceding claims, wherein said deflector element is an integral part of the air filter.

11. An air filter assembly according to any one of claims 1-9, wherein said deflector element is separate from the air filter.

12. An air filter assembly according to claim 11, wherein said deflector element is provided on a deflector frame separate from the air filter.

13. An air filter assembly according to any one of the preceding claims, wherein said at least one deflector element comprises an elongated fixed vane having a flat or curved surface adapted to deflect an air flow passing away from an adjacent inside surface of the air filter.

14. An air filter assembly according to any one of the preceding claims, wherein in a normal operating mode said adjacent inside surface of the air filter is inclined, such that liquid collected at said adjacent inside surface will be urged by force of gravity towards the open end of the air filter.

15. An air filter assembly according to any one of the preceding claims, further comprising a liquid collection system configured to receive liquid which exits the air filter through said liquid drain.

16. An air filter assembly according to claim 15, wherein said liquid collection system is provided in a deflector frame separate from the air filter.

17. A deflector frame for an air filter, said deflector frame defining at least one rectangular aperture for receiving an air flow to be filtered by the air filter, said deflector frame comprising: at least one deflector element extending along an edge portion of the rectangular aperture and adapted to deflect an air flow passing through the rectangular aperture away from an adjacent inside surface of an air filter; and at least one liquid drain arranged such that liquid collected at said adjacent inside surface of an air filter can exit the air filter through said liquid drain.

18. A deflector frame according to claim 17, wherein said liquid drain is arranged between said deflector element and said edge portion of the rectangular aperture, such that liquid collected at said adjacent inside surface of an air filter can exit the air filter through said liquid drain.

19. A deflector frame according to claim 17 or 18, further comprising a liquid collection system configured to receive liquid which exits the air filter through said liquid drain.

20. Use of an air filter assembly according to any one of claims 1-16 for filtration of air in wet or damp conditions.

21. Use according to claim 20, wherein said at least one rectangular aperture for receiving an air flow to be filtered is vertical, said deflector element extends alongside a bottom edge portion of the rectangular aperture, and said adjacent inside surface of the air filter is a bottom inside surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0084] Referring now to the drawings, which are exemplary embodiments, and wherein:

[0085] FIG. 1 is a perspective view of an embodiment of the inventive air filter;

[0086] FIG. 2 is a perspective view of a partially assembled embodiment of the inventive air filter and a magnified view of the position of the deflector element;

[0087] FIG. 3 is a cross sectional view of the deflector element and liquid drain;

[0088] FIG. 4a-4c is a schematic cross-sectional view of various deflector element and liquid drain configurations;

[0089] FIG. 5a is a perspective view of an embodiment of the inventive deflector frame;

[0090] FIG. 5b is a cross sectional view of the deflector element and liquid drain of the inventive deflector frame.

[0091] FIG. 6a-6c is a schematic cross-sectional view of various deflector element and liquid drain configurations with a deflector frame;

[0092] FIG. 7a is a perspective view of an embodiment of the inventive air filter;

[0093] FIG. 7b is a cross sectional view of the air filter of FIG. 7a showing the deflector element and liquid drain.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0094] The air filter assembly will be further described with reference to an embodiment in which the air filter is a V-type air filter. However, it should be understood that the the air filter could also be a panel filter or a deep pleat box filter.

[0095] The V-type air filter 100, shown in FIG. 1 comprises a filter frame 102, and several, in this embodiment eight, rectangular pleated filter elements 104 carried by the filter frame 102. The filter elements 104 are arranged in pairs in a V configuration having an open end 106, a closed end 108 and two V-shaped ends 110a, 110b. Although the invention will be described mainly with reference to a 4V embodiments, it is understood that the invention is equally applicable to 1V, 2V, 3V or more V configurations, i.e. filter assemblies comprising 2, 4, 6, or more filter elements. The filter elements can be of any suitable kind, but typically each filter element comprises a sheet of filter media, which has been pleated to an accordion shape in order to increase the effective filtering area of the filter body.

[0096] Although the filter is shown having pleated filter elements, it is contemplated that the filter elements may be comprised of carbon beds or other gas phase filter medium. The filter element may be suitable for at least one of liquid phase, gas phase, particulate or molecular filtration. In one embodiment, the filter element may be a molecular filtration media, such as bed of carbon or other gas phase absorber.

[0097] The filter frame 102 comprises a front frame 112, here in the form of a front plate, two side plates 114a, 114b and a rear plate 116, embodied by four separate plate elements. In order to secure the filter elements 104 to the frame structure 102 and prevent air from bypassing the filter elements, the filter elements are adhered and sealed against the frame structure by means of an adhesive. The front frame 112 is sealed to the filter elements at the open end 106, the rear plate elements 116 are sealed to the filter elements at the closed end 108, and the two side plates 114a, 114b are connected to the front and rear plates and sealed to the filter elements at the V-shaped ends 110a, 110b.

[0098] The pleated filter elements 104 are arranged such that the pleated zig-zag edges of the rectangular pleated filter elements are sealed to the side plates 114a, 114b, and the straight edges of the rectangular pleated filter elements 104 are sealed to the front frame 112 and rear plate(s) 116 respectively.

[0099] V-type air filters are provided in a wide variety of sizes. A common type has a substantially square front frame of about 600×600 mm. The height of the front frame may vary, but is often 20 mm or 25 mm.

[0100] The air flow direction through the filter is indicated by arrow 118. The direction of the arrow is orientated as V-type filters are typically utilized.

[0101] The front frame of the V-type air filter assembly defines four rectangular apertures 120 for receiving the air flow to be filtered. Each rectangular aperture 120 corresponds to the open end 106 of one of the pairs of filter elements arranged in a V configuration.

[0102] During operation, air to be filtered is passed in the direction of the arrow 118 from a “dirty” upstream side to a “clean” downstream side of the filter. The air to be filtered passes through a rectangular aperture 120 defined by the front frame 112, and into a V-shaped upstream space defined by the pair of filter elements 104 forming a V-shape, and the opposing side plates 114a, 114b at the V-shaped ends 110a, 110b of the space. The air then passes through the porous filter media of the filter elements 104 to the “clean” downstream side of the filter.

[0103] During operation of the filter in wet or damp environments, substantial amounts of water will be separated from the incoming air, accumulate on the surfaces of the filter elements 104, and eventually trickle down to the V-shaped bottom 122a of the frame structure by force of gravity. Water collected at the bottom of the V is then expected to drain out through the open end 106 of the filter.

[0104] The front frame 112 of the V-type air filter assembly 100 further comprises a deflector element 130a extending alongside an edge portion 132a of the rectangular aperture 120 and adapted to deflect an air flow passing through the aperture 120 away from an adjacent inside surface 122a of the V-type air filter. In this embodiment, the deflector element 130a is an integral part of the front frame 112 of the V-type air filter. The deflector element 130a has the form of an elongated fixed vane having a curved surface adapted to deflect an air flow passing the deflector element away from an adjacent inside surface of the V-type air filter.

[0105] The front frame 112 of the V-type air filter assembly further comprises a second deflector element 130b, provided at the opposing edge portion 132b of the rectangular aperture 120 adjacent the opposing V-shaped ends 122b of the V-type air filter. This allows for the filter assembly 100 to be mounted with either side plate (114a or 114b) as the bottom side plate.

[0106] The unobstructed cross sectional area of the rectangular aperture is at least 95%. In other words, the deflector elements block no more than 5%, of the cross sectional area of the rectangular aperture. In order to minimize obstructions of the air flow and resulting pressure drop, the cross sectional area of the rectangular aperture is free from other obstructions besides the deflector element(s).

[0107] A liquid drain 140a, 140b in the form of a slot is arranged between each deflector element 130a, 130b and the corresponding edge portion 132a, 132b of the rectangular aperture 120, such that liquid collected at said adjacent inside surface 122a or 122b of the V-type air filter can exit the V-type air filter through the liquid drain 140a, 140b.

[0108] The inside surface 122a, 122b of the V-type air filter is slightly inclined, such that liquid collected at said adjacent inside surface will be urged by force of gravity towards the open end 106 of the V-type air filter.

[0109] FIG. 2 depicts partially assembled embodiment of the inventive V-type air filter 100 with three of the pairs of filter elements removed. The partial magnified view shows the position of the deflector element 130a.

[0110] The deflector element 130a extends alongside an edge portion 132a of the rectangular aperture 120 and is adapted to deflect an air flow passing through the rectangular aperture away from the adjacent inside surface 122a of the V-type air filter. In this embodiment, the deflector element 130a is an integral part of the front frame 112 of the V-type air filter. The deflector element 130a has the form of an elongated fixed vane having a curved surface adapted to deflect an air flow passing the deflector element away from the adjacent inside surface of the V-type air filter.

[0111] The front frame 112 is rectangular and comprises a peripherally extending rim, and parallel troughs extending between opposite rim sides of the front frame. The front frame 112 is formed in a single piece, having a first coupling portion configured to receive the front edge portion of the first side plate 114a, and a second coupling portion configured to receive the front edge portion of the second side plate 114b.

[0112] The side plates 114a, 114b are arranged at the opposite rim sides of the front frame 112. The side plates include an exterior side and an interior side. Each side plate extends perpendicular to the front frame, and rearwards therefrom. The filter elements 104 are plate shaped and extend obliquely substantially in the direction of the air flow from the front frame 112, although they extend close to perpendicular to the front frame. The filter elements are arranged side by side, leaning alternately to one side and to the other side. More particularly, they are arranged in pairs, each pair forming a V shape, such that the mouth of the V shape faces the front frame 112. A front edge of each filter element is received in one of the troughs, and apertures between the troughs are aligned with the mouths of the V shapes. Each side plate 114a, 114b has four V-shaped portions extending between the front edge portion and an opposite rear edge portion of the side plate, with the mouth of each V-shaped portion facing the front edge portion.

[0113] Reinforcing elements 124 may be provided extending between adjacent V-shaped portions to further increase the structural rigidity of the side plates 114a, 114b. These reinforcing elements can also serve as handles when handling the side plates or (semi-) assembled filter frame assemblies. Each V-shaped portion is defined by a channel, having side walls. Each V-shaped channel 126 is adapted to receive side edge portions, of two filter elements 104. Of course, it is also possible for the side plates to have more or less than four V-shaped portions, such as one, two, three or more. Also, the side plates may not have V-shaped portions at all but may for example be provided in the form of a cover having a rectangular or trapezoidal shape or similar without openings between adjacent pairs of filter elements. Each plate element of the rear plate 116 covers rear edge portions of two filter elements forming a V-shape. The pleated filter elements 104 are arranged such that the pleated zig-zag edges of the rectangular pleated filter elements are sealed to the side plates 114a, 114b, and the straight edges of the rectangular pleated filter elements 104 are sealed to the front frame 112 and rear plate(s) 116 respectively. Consequently, the front frame, the side plates, and the rear plate support each other to form a strong filter frame, which carries the filter elements.

[0114] FIG. 3 is a cross sectional view of the deflector element and liquid drain. The deflector element 130a extends alongside an edge portion 132a of the rectangular aperture 120 and is adapted to deflect an air flow passing through the rectangular aperture away from the adjacent inside surface 122a of the V-type air filter. In this embodiment, the deflector element 130a is an integral part of the front frame 112 of the V-type air filter. The deflector element 130a has the form of an elongated fixed vane having a curved surface adapted to deflect an air flow passing the deflector element away from an adjacent inside surface of the V-type air filter.

[0115] The liquid drain 140a in the form of a slot is arranged between said deflector element 130a and said edge portion 132a of the rectangular aperture 120, such that liquid collected at said adjacent inside surface 122a of the V-type air filter can exit the V-type air filter through the liquid drain 140a.

[0116] FIG. 4a-4c show different configurations of the deflector element 130a and liquid drain 140a in the front frame 112 of the V-type filter. Arrow 144 illustrates the deflected air flow and arrow 146 illustrates the draining water. FIG. 4c also includes an optional liquid collection system 150 configured to receive liquid which exits the V-type air filter through said liquid drain 140a.

[0117] In an alternative embodiment (not shown), the deflector element is arranged on the front side of the front frame and the liquid drain is arranged as a gap formed between the deflector element and the adjacent inside surface of the air filter, such that liquid collected at the adjacent inside surface of the air filter can exit the air filter through said liquid drain.

[0118] FIGS. 5a and 5b depict a separate deflector frame 160 for attachment to the front frame of a V-type air filter which does not have a deflector element and liquid drain. The deflector frame 160 defines a rectangular aperture 162 configured to correspond to a rectangular aperture of the V-type air filter. The deflector frame 160 further comprises a deflector element 164a extending alongside an edge portion 166a of the rectangular aperture 162 and adapted to deflect an air flow passing through the rectangular aperture away from an adjacent inside surface of a V-type air filter to which the deflector frame 160 is attached. The deflector element 164a has the form of an elongated fixed vane having a curved surface adapted to deflect an air flow passing the deflector element away from an adjacent inside surface of a V-type air filter.

[0119] The deflector frame 160 further comprises a second deflector element 164b, provided at the opposing edge portion 166b of the rectangular aperture 162 adjacent the opposing V-shaped ends of the V-type air filter.

[0120] A liquid drain 168a, 168b in the form of a slot is arranged between the deflector element 164a, 164b and the edge portion 166a, 166b of the rectangular aperture 162, such that liquid collected at an adjacent inside surface of a V-type air filter can exit the V-type air filter through the liquid drain.

[0121] The deflector frame 160 can be attached to the front frame of a V-type air filter using for example a snap lock or clamping functionality (not shown).

[0122] FIG. 6a-6c show different configurations of the deflector element 164a and liquid drain 168a in the deflector frame 160. Arrow 144 illustrates the deflected air flow and arrow 146 illustrates the draining water. In FIGS. 6a and 6b, the deflector element 164a and liquid drain 168a are both included in the deflector frame. In FIG. 6c, the deflector element 164a is included in the deflector frame, but the liquid drain 168a is formed by a spacing between the deflector frame 160 and the front frame 170 of the V-type air filter. FIG. 6c also includes an optional liquid collection system 150 configured to receive liquid which exits the V-type air filter through the liquid drain.

[0123] FIG. 7a shows an alternative embodiment in which the air filter is a panel filter. The panel filter 200 has a rectangular pleated filter element 204 and a rectangular filter frame 202 having the pleated filter element 204 disposed therein. The filter frame 202 includes a first pair of opposing side plates 206a, 206b sealed to the pleated edges of the rectangular pleated filter element and a second pair of opposing side plates 208a, 208b sealed to the non-pleated edges of the rectangular pleated filter element. The rectangular filter frame 202 forms a front frame 212 (not shown) defining a rectangular aperture 220 for receiving an air flow to be filtered. The panel filter 200 is provided with a deflector element 230 and a liquid drain (not shown) between the deflector element 230 and the front frame 212.

[0124] FIG. 7b is a cross-sectional view of the panel filter 200 of FIG. 7a showing the deflector element 230 and the liquid drain 240. The deflector element 230 is arranged on the front side of the front frame 212 and the liquid drain 240 is arranged as a gap formed in the front frame 212 between the deflector element 230 and the adjacent inside surface of the air filter, such that liquid collected at the adjacent inside surface of the air filter can exit the air filter through said liquid drain.

[0125] While the invention has been described herein with reference to various exemplary embodiments, it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted for elements thereof, without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or feature to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Furthermore, it would be understood by the person skilled in the art what features of the different embodiments can be combined although not explicitly written above.