Filter Element Assembly

Abstract

A filter element assembly (10) is disclosed comprising: a filter element (12) for location in a housing (4) of a filter (2), comprising a wall (16) of a filtration medium which defines a hollow space (18), for a gas stream to flow from the space through the wall, the filtration medium including a filtration layer (20), and a drainage layer (22) located outside the filtration layer, first (24) and second (26) end caps at opposite ends of the wall, one including a port (28) for a gas stream which communicates with the space; and a drainage promoter (14) comprising a fin (46) which can be fitted to the filter element so that it extends along the filter element substantially an entire distance between the first and second end caps, the fin compressing the drainage layer along its length to promote drainage of liquid which has collected in the drainage layer.

Claims

1. A filter element assembly, comprising: a filter element for location in a housing of a filter, the filter element comprising a wall of a filtration medium which defines a hollow space, for a gas stream to flow from the space through the wall to be filtered, the filtration medium including a filtration layer, and a drainage layer located outside the filtration layer in which liquid separated from the gas stream can collect, and first and second end caps at opposite ends of the wall, one of the end caps including a port for a gas stream which communicates with the space within the wall; and a drainage promoter comprising a fin configured to be connected to the filter element so that, in use, it extends along the filter element substantially an entire distance between the first and second end caps and compresses the drainage layer along its length to promote drainage of liquid which has collected in the drainage layer, and wherein the fin comprises at least one connection feature for engaging the filter element, to connect the fin to the filter element.

2. The filter element assembly as claimed in claim 1, in which the fin is elongate, having first and second axial ends, a base extending along a length of the fin between the ends, and a tip opposite the base and extending along the length of the fin, in which the tip defines a free edge of the fin and the base presses into the drainage layer during use.

3. The filter element assembly as claimed in claim 2, in which the tip defines a discharge location from which liquid flowing from the drainage layer can be discharged from the fin, and in which the fin has a tapered shape in cross-section, tapering in a direction towards its tip.

4. The filter element assembly as claimed in claim 1, in which the fin is configured to be connected to at least one of the first and second end caps, so that it can be secured to the filter element.

5. The filter element assembly as claimed in claim 4, in which the fin is configured to be connected to both end caps so that it extends from one end cap to the other end cap.

6. The filter element assembly as claimed in claim 1, in which the fin is configured to be releasably connected to at least one of the end caps.

7. The filter element assembly as claimed in claim 1, in which the connection feature engages an end cap of the filter element.

8. The filter element assembly as claimed in claim 7, in which the fin comprises a first connection feature for engaging one of the end caps, and a second connection feature for engaging the other one of the end caps, the first and second connection features being spaced apart along a length of the fin.

9. The filter element assembly as claimed in claim 8, in which the fin comprises a first axial end and a second axial end, and the first and second connection features are provided at or near the respective first and second axial ends.

10. The filter element assembly as claimed in claim 7, in which the filter element comprises at least one connection feature, which cooperates with the connection feature on the fin for connecting the fin to the element.

11. The filter element assembly as claimed in claim 10, in which at least one of the end caps comprises the connection feature.

12. The filter element assembly as claimed in claim 11, in which the first end cap comprises a first connection feature and the second end cap comprises a second connection feature, the first and second end cap connection features being configured to cooperate with respective first and second connection features of the fin, to connect the fin to the filter element.

13. The filter element assembly as claimed in claim 10, in which: the connection feature of the fin is a male connection feature, and the connection feature of the filter element is a corresponding female connection feature; or the connection feature of the fin is a female connection feature, and the connection feature of the filter element is a corresponding male connection feature.

14. The filter element assembly as claimed claim 1, comprising a pivoting connection between the fin and the filter element.

15. The filter element assembly as claimed in claim 14, in which one of the fin and the filter element defines a connection feature in the form of a pivot pin, and the other one of the fin and the filter element defines a pivot mount shaped to receive the pivot pin, so that the fin can pivot relative to the filter element.

16. The filter element assembly as claimed in claim 15, in which the pivot pin and the pivot mount are aligned along a longitudinal axis of the fin, so that the fin can pivot about its longitudinal axis between a folded position and a deployed position.

17. The filter element assembly as claimed in claim 15, in which the fin comprises a pivot pin or a pivot mount at each of its ends, configured to engage a corresponding pivot mount or pivot pin of the filter element.

18. The filter element assembly as claimed in claim 15, in which the pivot pin and the pivot mount are disposed on a pivot axis which is transverse to the longitudinal axis of the fin when the fin is connected to the filter element.

19. The filter element assembly as claimed in claim 18, in which the fin comprises a first pivot pin portion extending in a first lateral direction away from the fin, and a second pivot pin portion extending in a second lateral direction away from the fin.

20. The filter element assembly as claimed in claim 18, in which the fin is pivotable about the pivot axis between a disconnected position in which the fin is not connected the filter element, and a connected position in which the fin is connected to the filter element, and in which, in the connected position, the longitudinal axis of the fin is disposed substantially parallel to a longitudinal axis of the filter element.

21. The filter element assembly as claimed in claim 18, in which the fin and the filter element define respective latch features, which cooperate to provide a latching engagement between the fin and the element.

22. The filter element assembly as claimed in claim 21, in which the latch feature on the fin is spaced along a length of the fin from its pivot pin or pivot mount, and the latch feature on the filter element is provided on one of the end caps.

23. The filter element assembly as claimed in claim 21, in which one of the latch features provided by the fin and the filter element is a resiliently deformable latch arm.

24. The filter element assembly as claimed in claim 10, comprising a sliding connection between the fin and the filter element, the sliding connection defined by connection features of the fin and the filter element.

25. The filter element assembly as claimed in claim 24, in which the fin is translatable relative to the filter element between a disconnected position in which it is not connected to the filter element, and a connected position in which it is connected to the filter element.

26. The filter element assembly as claimed in claim 24, in which one of the fin and the filter element defines a connection feature in the form of a key, and the other one of the fin and the filter element defines a keyway shaped to receive the key in a sliding fit.

27. The filter element assembly as claimed in claim 24, in which the first end cap comprises a first connection feature for engaging a corresponding first connection feature on the fin, the second end cap comprises a second connection feature for engaging a corresponding second connection feature on the fin, and in which the respective first connection features of the filter element and the fin, and the respective second connection features of the filter element and the fin, require to be aligned in order for the fin to be connected to the element.

28. The filter element assembly as claimed in claim 24, in which at least one of the end caps comprises a plurality of connection features which are spaced around a perimeter of the end cap.

29. The filter element assembly as claimed in claim 1, in which the fin is configured so that it is connected to the filter element in a press-fit between the end caps.

30. The filter element assembly as claimed in claim 1, in which the drainage promoter comprises at least one drainage element which is coupled to the fin and extends in a direction away from the fin and around an outer surface of the drainage layer.

31. The filter element assembly as claimed in claim 30, in which the drainage element extends part way around a perimeter of the outer surface and is disposed transverse to a longitudinal axis of the fin.

32. The filter element assembly as claimed in claim 1, in which the at least one drainage element has a base at which it is coupled to the fin and extends away from the base to a tip which defines a free end, the at least one drainage element tapering in a direction from the base towards the tip.

33. The filter element assembly as claimed in claim 30, in which, in use, at least one first drainage element extends from the fin around the outer surface of the drainage layer in a first direction around the perimeter of the filter element, and at least one second drainage element extends from the fin around the outer surface of the drainage layer in a second direction around the perimeter of the filter element.

34. The filter element assembly as claimed in claim 33, in which the first and second drainage elements extend from respective first and second flanks of the fin.

35. The filter element assembly as claimed in claim 33, in which, in use, the first and second drainage elements are configured to together impart a clamping force on the filter element, for connecting the drainage promoter to the element.

36. The filter element assembly as claimed in claim 33, in which, in use, the drainage elements each extend around the perimeter of the filter element to an over-centre position, relative to a central axis of the filter element, so that the first and second drainage elements together encompass more than half of a circumference of the filter element.

37. The filter element assembly as claimed in claim 33, in which the first and second drainage elements together describe a generally cylindrical passage between their inner surfaces, which passage is shaped to receive the filter element.

38. The filter element assembly as claimed in claim 37, in which the passage has a central axis, and the drainage elements each extend, in use, to an over-centre position relative to the central axis.

39. The filter element assembly as claimed in claim 33, in which a space is defined between a free end of the first drainage element and a free end of the axially adjacent second drainage element, and in which a dimension of the space, measured in a direction perpendicular to a longitudinal axis of the filter element, is smaller than a width of the filter element.

40. The filter element assembly as claimed in claim 30, in which the drainage promoter comprises a first part defining a first part of the fin and at least one drainage element, and a second part defining a second part of the fin and at least one drainage element, and in which the first and second fin parts are adapted to be coupled together to form the drainage promoter.

41. The filter element assembly as claimed in claim 1, in which the drainage promoter is configured to be connected to the filter element at a location between the first and second end caps.

42. The filter element assembly as claimed in claim 41, in which the drainage promoter comprises at least one connecting component which is configured to engage the drainage layer, to connect the fin to the filter element.

43. The filter element assembly as claimed in claim 42, in which the connecting component is a strap which extends, in use, from the fin and around at least part of a perimeter of the drainage layer.

44. The filter element assembly as claimed in claim 43, in which the strap comprises a first strap portion extending, in use, in a first direction away from the fin and around part of a perimeter of the drainage layer, and a second strap portion extending in a second direction away from the fin and around part of a perimeter of the drainage layer, and in which the first and second strap portions are adapted to be coupled together to connect the fin to the filter element.

45. A drainage promoter which can be connected to a filter element, the drainage promoter comprising: at least one fin which can be fitted to the filter element so that it extends along the filter element substantially an entire distance between first and second end caps of the filter element, to compress a drainage layer of the filter element along its length and promote drainage of liquid which has collected in the drainage layer; in which the fin comprises a first connection feature configured to engage the first end cap of the filter element, and a second connection feature configured to engage the second end cap of the filter element, for connecting the fin to the filter element.

46. A drainage promoter which can be connected to a filter element, the drainage promoter comprising: at least one fin which can be fitted to the filter element so that it extends along the filter element substantially an entire distance between the first and second end caps, to compress a drainage layer of the filter element along its length and promote drainage of liquid which has collected in the drainage layer; and at least one connecting component configured to engage the drainage layer to connect the fin to the filter element.

47. A drainage promoter which can be connected to a filter element, the drainage promoter comprising: at least one fin which can be fitted to the filter element so that it extends along the filter element substantially an entire distance between the first and second end caps, to compress a drainage layer of the filter element along its length and promote drainage of liquid which has collected in the drainage layer, the fin having first and second axial ends and a longitudinal axis extending along the fin between its axial ends; and at least one drainage element coupled to the fin and extending in a direction away from the fin, transverse to its longitudinal axis.

48. A method of improving drainage of liquid from a drainage layer of an existing filter element, the method comprising fitting a drainage promoter according to claim 47 to the drainage layer of the filter element.

49. A filter element for location in a housing of a filter, the filter element comprising: a wall of a filtration medium which defines a hollow space, for a fluid stream to flow from the space through the wall to be filtered, the filtration medium including a filtration layer, and a drainage layer located outside the filtration layer in which fluid separated from the fluid stream can collect; first and second end caps at opposite ends of the wall, one of the end caps including a port for a fluid stream which communicates with the space within the wall; and at least one connection feature configured to cooperate with a connection feature on a drainage promotor fin, for connecting the filter element to the drainage promotor fin.

50. A filter element assembly, comprising: a filter element for location in a housing of a filter, the filter element comprising a wall of a filtration medium which defines a hollow space, for a gas stream to flow from the space through the wall to be filtered, the filtration medium including a filtration layer, and a drainage layer located in surrounding relation to the filtration layer in which liquid separated from the gas stream can collect, and first and second end caps at opposite ends of the wall, one of the end caps including a port for a gas stream which communicates with the hollow space within the wall; and a drainage promoter comprising a fin connected to the filter element so that, the drainage promoter extending along the filter element substantially an entire distance between the first and second end caps and compressing the drainage layer along its length to promote drainage of liquid which has collected in the drainage layer during use, and wherein the fin comprises at least one connection feature for engaging the filter element, to connect the fin to the filter element.

51. The filter element assembly as claimed in claim 50, in which the first end cap comprises a first connection feature and the second end cap comprises a second connection feature, the first and second end cap connection features being configured to cooperate with respective first and second connection features of the fin, to connect the fin to the filter element.

52. The filter element assembly as in claim 50, in which the first and second connection features of the first and second end caps are configured to releasably connect the fin to the filter element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0080] FIG. 1 is a front view of a filter element assembly in accordance with an embodiment of the present disclosure;

[0081] FIG. 1A is a longitudinal cross-sectional view of a filter comprising the filter element assembly of FIG. 1, drawn to a smaller scale;

[0082] FIG. 2 is an end view of the filter element assembly shown in FIG. 1, taken in the direction of the arrow A in FIG. 1;

[0083] FIG. 3 is an end view of the filter element assembly shown in FIG. 1, taken in the direction of the arrow B in FIG. 1;

[0084] FIG. 4 is a longitudinal cross-sectional view of the filter element assembly shown in FIG. 1;

[0085] FIG. 5 is a front view of a drainage promoter forming part of the filter element assembly shown in FIG. 1;

[0086] FIG. 6 is an end view of a drainage promoter forming part of the filter element assembly shown in FIG. 1;

[0087] FIG. 7 is a perspective view of a drainage promoter forming part of the filter element assembly shown in FIG. 1

[0088] FIG. 8 is a perspective view of the filter element assembly shown in FIG. 1, drawn to a smaller scale;

[0089] FIG. 9 is an end view of the filter element assembly, drawn to the smaller scale of FIG. 8, and showing fitting of the drainage promoter to a filter element of the assembly;

[0090] FIG. 10 is a perspective view of the filter element assembly, drawn to the smaller scale of FIG. 8, and showing fitting of the drainage promoter to a filter element of the assembly;

[0091] FIG. 11 is a front view of a filter element assembly in accordance with another embodiment of the present disclosure;

[0092] FIG. 12 is an end view of the filter element assembly shown in FIG. 11, taken in the direction of the arrow A in FIG. 11;

[0093] FIG. 13 is an end view of the filter element assembly shown in FIG. 11, taken in the direction of the arrow B in FIG. 11;

[0094] FIG. 14 is a perspective view of the filter element assembly shown in FIG. 11, drawn to a smaller scale;

[0095] FIG. 15 is a longitudinal cross-sectional view of the filter element assembly shown in FIG. 11, drawn to a smaller scale;

[0096] FIG. 16 is an end view of the filter element assembly, drawn to the smaller scale of FIG. 14, and showing fitting of a drainage promoter to a filter element of the assembly;

[0097] FIG. 17 is a front view of the drainage promoter forming part of the filter element assembly shown in FIG. 11;

[0098] FIG. 18 is an end view of the drainage promoter forming part of the filter element assembly shown in FIG. 11;

[0099] FIG. 19 is a perspective view of the drainage promoter forming part of the filter element assembly shown in FIG. 11;

[0100] FIG. 20 is an enlarged detail view showing connection features of the filter element and the drainage promoter following connection of the drainage promoter to the filter element;

[0101] FIG. 21 is a further enlarged detail view showing connection features of the filter element and the drainage promoter following connection of the drainage promoter to the filter element;

[0102] FIG. 22 is a front view of a filter element assembly in accordance with a further embodiment of the present disclosure;

[0103] FIG. 23 is an end view of the filter element assembly shown in FIG. 22, taken in the direction of the arrow A in FIG. 22;

[0104] FIG. 24 is an end view of the filter element assembly shown in FIG. 22, taken in the direction of the arrow B in FIG. 22;

[0105] FIG. 25 is a longitudinal cross-sectional view of the filter element assembly shown in FIG. 22;

[0106] FIG. 26 is a perspective view of the filter element assembly shown in FIG. 22, illustrating a drainage promoter being fitted to a filter element of the assembly;

[0107] FIG. 26A is a side view of the filter element assembly shown in FIG. 22, showing a first step fitting of a drainage promoter to a filter element of the assembly;

[0108] FIG. 26B is a side view of the filter element assembly shown in FIG. 22, showing a second step fitting of a drainage promoter to a filter element of the assembly;

[0109] FIG. 26C is a side view of the filter element assembly shown in FIG. 22, showing a third step fitting of a drainage promoter to a filter element of the assembly;

[0110] FIG. 27 is a side view of the drainage promoter forming part of the assembly of FIG. 22;

[0111] FIG. 28 is an end view of the drainage promoter forming part of the assembly of FIG. 22;

[0112] FIG. 29 is a perspective view of the drainage promoter forming part of the assembly of FIG. 22;

[0113] FIG. 30 is a front view of a filter element assembly in accordance with a further embodiment of the present disclosure;

[0114] FIG. 31 is a front view of a drainage promoter forming part of the filter element assembly shown in FIG. 30;

[0115] FIG. 32 is an end view of a drainage promoter forming part of the filter element assembly shown in FIG. 30;

[0116] FIG. 33 is a perspective view of a drainage promoter forming part of the filter element assembly shown in FIG. 30;

[0117] FIG. 34 is a front view of a filter element assembly in accordance with a further embodiment of the present disclosure;

[0118] FIG. 35 is an end view of the filter element assembly shown in FIG. 34, taken in the direction of the arrow A in FIG. 34;

[0119] FIG. 36 is an end view of the filter element assembly shown in FIG. 34, taken in the direction of the arrow B in FIG. 34;

[0120] FIG. 37 is a perspective view of the filter element assembly shown in FIG. 34, drawn to a smaller scale;

[0121] FIG. 38 is a longitudinal cross-sectional view of the filter element assembly shown in FIG. 34, drawn to a smaller scale;

[0122] FIG. 39 is a front view of a drainage promoter forming part of the filter element assembly shown in FIG. 34, drawn to a smaller scale;

[0123] FIG. 40 is an end view of a drainage promoter forming part of the filter element assembly shown in FIG. 34, drawn to a smaller scale;

[0124] FIG. 41 is a perspective view of a drainage promoter forming part of the filter element assembly shown in FIG. 34, drawn to a smaller scale;

[0125] FIG. 42A is an end view of the filter element assembly of FIG. 34, shown during fitting of the drainage promoter to the filter element;

[0126] FIG. 42B is an end view of the drainage promoter forming part of the filter element assembly of FIG. 34, showing assembly of the drainage promoter;

[0127] FIG. 43 is a front view of a filter element assembly in accordance with a further embodiment of the present disclosure;

[0128] FIG. 44 is an end view of the filter element assembly shown in FIG. 43, taken in the direction of the arrow A in FIG. 43;

[0129] FIG. 45 is an end view of the filter element assembly shown in FIG. 43, taken in the direction of the arrow B in FIG. 43;

[0130] FIG. 46 is a front view of a drainage promoter forming part of the filter element assembly shown in FIG. 43, drawn to a smaller scale;

[0131] FIG. 47 is an end view of a drainage promoter forming part of the filter element assembly shown in FIG. 43, drawn to a smaller scale;

[0132] FIG. 48 is a perspective view of a drainage promoter forming part of the filter element assembly shown in FIG. 43, drawn to a smaller scale;

[0133] FIG. 49 is a front view of the filter element assembly shown in FIG. 43, shown during fitting of the drainage promoter to a filter element of the assembly, drawn to a smaller scale;

[0134] FIG. 50 is an end view of the filter element assembly shown in FIG. 43, shown during fitting of the drainage promoter to a filter element of the assembly, drawn to a smaller scale;

[0135] FIG. 51 is a longitudinal cross-sectional view of the filter element assembly shown in FIG. 43, drawn to the smaller scale of FIG. 49 and shown following fitting of the drainage promoter to the filter element; and

[0136] FIG. 52 is a perspective view of the filter element assembly shown in FIG. 43, drawn to the smaller scale of FIG. 49 and shown following fitting of the drainage promoter to the filter element.

DETAILED DESCRIPTION

[0137] Turning firstly to FIG. 1, there is shown a front view of a filter element assembly in accordance with an embodiment of the present disclosure, the filter element assembly indicated generally by reference numeral 10. The filter element assembly 10 is also shown in the end views of FIGS. 2 and 3, taken in the direction of the arrows A and B respectively in FIG. 1, and the longitudinal cross-sectional view of FIG. 4, which is drawn to a larger scale.

[0138] In use, and as is well known in the field of fluid filters, the filter element assembly 10 is located in a filter 2, as shown in the cross-sectional view of FIG. 1A, drawn to a smaller scale. The filter element assembly 10 is located within a chamber defined by a housing 4 of the filter 2. The housing 4 includes an opening 5 through which the filter element assembly 10 can be inserted into the housing for location in the chamber 3. A cover 6 is then coupled to the housing 4, to secure the filter element assembly 10 in the chamber 3 so that fluid to be filtered can be directed through the filter element assembly 10, from a filter head 7. A tie-rod 8 secures the filter element assembly 10 within the housing 4. Gas to be filtered enters the filter head 7 through a port 9 and flows into the filter element assembly 10 to be filtered.

[0139] The filter element assembly 10 comprises a filter element 12, and a drainage promoter, which is indicated by reference numeral 14. As best shown in FIG. 4, the filter element 12 comprises a wall 16 of a filtration medium defining a hollow space 18, for a gas stream to flow from the space through the wall to be filtered. The filtration medium includes a filtration layer 20, and a drainage layer 22 located outside the filtration layer, in which liquid separated from the gas stream can collect. Filter elements having such filtration and drainage layers are well known in the field of fluid filters, and persons skilled in the art will appreciate their general construction and operation during use. Accordingly, the filtration and drainage layers 20 and 22, including their materials and methods of manufacture, will not be described in detail in this document. In general terms however, the filtration and drainage layers 20 and 22 may have the following features.

[0140] The material for the filtration medium in the filtration layer 20 of the filter element 12 will be selected according to the nature of the gas that is to be filtered, the nature of the contaminants (liquid droplets, aerosols, solid particles etc.) to be filtered from the gas, the pressure differential across the filter and so on. Such materials are known, including those used by Parker Domnick Hunter in products which are available under the trademark OIL-X. Suitable materials include, but are not restricted to, borosilicate and other glass fibres, activated carbon minerals, activated silica materials and so on.

[0141] The filtration layer 20 can be made from woven fibres. However, as will be appreciated, the filtration layer can be made from sheets of non-woven fibres. For example, a microfibre filtration layer made from fine organic or inorganic fibres may be employed. A coarser fibre layer may be fitted on the inside of a microfibre filtration layer, which may protect a microfibre filtration layer from gross pollution. The filtration layer 20 may comprise a layer of a material which has been folded so that it is fluted (or pleated). This can increase the surface area of the filtration layer 20 through which gas flowing through the filter element 12 will pass. This can also help to increase the rigidity of the filtration layer 20.

[0142] The drainage layer 22 comprises a material that is capable of retaining liquid that has been coalesced by the filtration layer 20 and is carried to the drainage layer by the gas stream that flows through the drainage layer. The drainage layer 22 will generally be porous and made from a material which encourages flow of coalesced liquid towards the base of the filter element 12. Factors affecting the drainage characteristics may include pore size and structure, and the material of the drainage layer 22, including for example the surface energy of liquid which is in contact with the material. Materials suitable for use in the drainage layer are used in similar products sold by Parker Domnick Hunter under the trade mark OIL-X. Suitable materials include open-celled foam plastics, felted fabric material, expanded foam materials, woven and non-woven materials.

[0143] The filter element 12 also comprises first and second end caps 24 and 26 at opposite ends of the wall 16, the first end cap including a port 28 for the gas stream to flow into the filter element from the filter head port 9, the filter port 28 communicating with the space 18 within the wall. In normal use of the filter, the filter element 12 will be substantially horizontally oriented as shown in FIG. 1A, so that the first end cap 24 defines a first lateral end of the filter element, and the second end cap 26 defines a second lateral end of the filter element.

[0144] Perforated tubular supports 30 and 32, typically of a metal or metal alloy material, are secured to the end caps 24 and 26, and serve for securing both the filtration layer 20 and the drainage layer 22 to the end caps and separating the different layers. As is well known in the field of the invention, this is suitably achieved by ‘potting’ the supports 30 and 32, and the filtration and drainage layers 20 and 22, within annular channels 34 and 36 defined by the end caps 24 and 26, using an adhesive such as an epoxy-based adhesive.

[0145] The filter head comprises a flow conduit 33 which defines the inlet port 9 and serves to direct a gas stream entering the filter head into the filter element 12 through its inlet port 28, so that contaminants in the gas stream can be removed. The filter may have a wide range of uses but may have a particular use in removing contaminants from a gas stream such as a compressed or vacuum gas stream which is to be used in an industrial application, to remove residual oil from a compressor used to pressurise the gas.

[0146] The first end cap 22 of the filter element 11 comprises a seal in the form of an O-ring 37 (FIG. 1A), which is mounted in a groove 38 defined in a tubular wall 40 of the end cap defining the port 28. The O-ring seal 37 serves for sealing the filter element 12 relative to the filter head conduit 33, so that gas entering the head is directed into the filter element. The gas stream entering the filter element 12 flows through its port 28 generally in a direction along an axis 42 of the filter element, and into the space 18. The gas stream containing the contaminants flows from the central space 18 radially outwardly, through the wall 16 of the filter element 12, passing through the filtration layer 20 and the drainage layer 22. The filtration layer 20 serves for filtering out contaminants, which as described above may be residual oil entrained in the gas stream. Oil droplets coalesce and enter the drainage layer 22, building up to form a ‘wet band’ towards a lower part of the drainage layer. The liquid oil in this wet band progressively drains from the lower part of the drainage layer 22 into a sump 43 of the filter housing 4 and can flow out of the sump via a drain 45.

[0147] The ‘clean’ gas stream exiting the drainage layer 22 flows out through an external surface 44 of the filter element 12 (defined by the drainage layer 22) and into the chamber 3, before passing to an outlet conduit 47 of the filter housing 4. The gas stream exiting the filter 2 flows on to a downstream location.

[0148] The filter element assembly 10 of the present disclosure also comprises the drainage promoter 14. The drainage promoter 14 is shown separately in the front and end views of FIGS. 5 and 6, and the perspective view of FIG. 7. The drainage promoter 14 comprises a fin 46 which can be fitted to the filter element 12 so that it extends along the filter element substantially an entire distance between its first and second end caps 24 and 26, as can be seen for example in FIGS. 1 and 4. The fin 46 acts to compress the drainage layer 22 of the filter element 12 along its length, to promote drainage of liquid which has collected in the drainage layer. In the exemplary use discussed above, this is oil which has coalesced from the gas flowing through the filter element 12, in the drainage layer 22. The drainage promoter fin 46 compresses the drainage layer 22 of the filter element 12, breaking the surface tension of the drainage layer material and promoting quicker and more deficient drainage of liquid from it. The filter element 12 and the drainage promoter 14 are capable of being connected to one another so that the filter element and the drainage promoter can be manipulated by a user as a unitary component for positioning in the housing 4 of the filter 2.

[0149] The fin 46 is elongate, having first and second axial ends 48 and 50. The fin 46 also comprises a base 52 which extends along a length of the fin between its axial ends 48 and 50, and a tip 54 which defines a free edge of the fin. The tip 54 is disposed opposite the base 52, and similarly extends along the length of the fin 46. A length dimension of the fin 46 measured between its two ends 48 and 50 is greater than a height dimension, measured from the base 52 to the tip 54. In the illustrated embodiment, the height dimension is substantially constant along the length of the fin 46. However, the height may vary along a length of the fin 46, for example the fin (in particular its base 52) may be curved and may be generally convex.

[0150] As discussed above, during use, the fin 46 presses into the drainage layer 22. This is best shown in the cross-sectional view of FIG. 4, the fin base 52 pressing into the drainage layer 22 to break the surface tension and promote drainage of liquid. Liquid flowing from the drainage layer 22 on to the fin 46 flows in a direction from the base 52 towards the tip 54, the tip defining a discharge location from which the liquid can be discharged from the fin into the housing sump 43, as discussed above. The fin 46 has a tapered shape in cross-section, taken in a direction which is perpendicular to a longitudinal axis 56 of the fin. This tapered shape can be best seen in the end and perspective views of FIGS. 6 and 7. Providing the fin 46 with such a tapered shape helps to promote the flow of liquid along the fin to its tip 54, and subsequent discharge. As can be seen, a cross-sectional width of the fin decreases in a direction away from its base 52 towards its tip 54. The base 52 has a generally rounded profile so as to reduce a likelihood of damaging the material of the drainage layer 22.

[0151] The fin 46 is releasably connectable to the filter element at its first and second end caps 24 and 26. Releasably connecting the fin 46 to the filter element 12 allows the drainage promoter to be fitted to the filter element following assembly of the element. It may also allow the drainage promoter 14 to be used with a further filter element, for example if the existing filter element in the filter 2 becomes clogged and requires replacement.

[0152] In the illustrated embodiment, the fin 46 comprises first and second connection features 58 and 60 at its first and second axial ends 48 and 50, which serve for connecting the fin to the filter element 12. The first and second connection features 58 and 60 each take the form of a male feature, in particular a protrusion or projection defining a pivot pin, as best shown in FIG. 7. The pivot pins 58 and 60 are generally cylindrically shaped and have respective rounded heads 59 and 61. The filter element 12 comprises corresponding first and second connection features 62 and 64, which cooperate respectively with the first and second connection features 58 and 60 of the fin 46. In the illustrated embodiment, the first and second connection features 62 and 64 of the filter element 12 are provided respectively on the first and second end caps 24 and 26 and are female connection features in the form of a pivot mount or socket which is shaped to receive the pins 58 and 60 of the fin 46. To this end, the sockets are typically circular in shape, defining a cylindrical space which can receive the cylindrical pins 58 and 60.

[0153] The pins 58 and 60, and the sockets 62 and 64, together provide a pivoting connection between the fin 46 and the filter element 12. The pins 58 and 60 can rotate within the sockets 62 and 64, so that the fin 46 can be pivoted between a folded or installation position, and a deployed or used position. Reference is made here to FIGS. 8, 9 and 10 which are a perspective view of the filter element 12, an end view taken in the direction of the arrow B in FIG. 1, and a front view similar to FIG. 1, respectively, all drawn to a smaller scale. The fin 46 is shown in its deployed position in FIG. 8 (as well as FIGS. 1 to 4). FIG. 9 also shows the fin 46 in its deployed position, as well as the folded position of the fin, which is indicated in the drawing with a broken line 66. The fin 46 can pivot between its folded position 66 and its deployed position in the direction of the arrow C in FIG. 9. When the fin 46 is in its folded position 66, the tip 54 of the fin is disclosed closer to the external surface 44 of the drainage layer 22 than when the fin is in its deployed position. A flank 68 of the fin is disposed proximate the external surface 44 when the fin is in its folded position. The ability of the fin 46 to fold or pivot in this way can facilitate fitting of the filter element assembly 10 in its filter housing, for example if access to the housing is restricted, such as in a tight or confined space, or if the housing opening 5 is small compared to the filter element assembly 10 with the fin deployed.

[0154] As can best be appreciated from FIGS. 5 to 7, the pivot pins 58 and 60 are aligned along the longitudinal axis 56 of the pin 46, so that the fin pivots about its longitudinal axis when it is moved between its folded and deployed positions. The portion of the fin 46 defining the base 52 extends a certain distance away from the longitudinal axis 56, so that the base 52 presses into the external surface 44 of the drainage layer 22 to compress it, when the fin is pivoted to its deployed position. Shaping the base 58 so that it is rounded as discussed above helps to prevent damage to the drainage layer 22 as the fin 46 pivots between its different positions.

[0155] Fitting of the fin 46 to the filter element 12 is shown in FIG. 10. The fin 46 is typically of a polymeric material and may be resiliently deformable for fitting to the filter element 12. The fin 46 may be fitted by locating one of the pivot pins 58 and 60 in its respective mounting socket 62 or 64 on the filter element 12. This requires that the fin 46 be disposed at an angle relative to the filter element 12, so that its longitudinal axis 56 is transverse to the filter element axis 42. The fin 46 can then be moved to a position in which the other one of the pivot pins 58 and 60 is proximate its mounting socket 62 or 64, and the fin resiliently deformed to a certain extent in order to snap the pivot pin into its socket. This may be achieved by deforming the fin 46 along its length, for example by causing it to adopt a curved shape, and/or the pin itself may be resiliently deformable so that it can pass into the socket. To facilitate fitting of the fin 46, the sockets 62 and 64 on the end caps 24 and 26 may comprise radially outer lips 70 and 72 forming outer wall portions of the sockets, over which the pivot pins 58 and 60 can pass in order to be received in the sockets.

[0156] Although the fin 46 can be fitted to the filter element 12 by locating the fin at a transverse angle relative to the filter element, the sockets 62 and 64 on the end caps 24 and 26, and in particular their lips 70 and 72, may be dimensioned so that the fin 46 can be press-fitted to both sockets at the same time. This is shown in FIG. 10 and can be achieved by bringing the fin 46 adjacent to the filter element 12 with the fin axis 56 substantially parallel to the filter element axis 42. The pivot pins 58 and 60 can then be press fitted into the sockets, passing over the lips 70 and 72, this involving a small deformation of the fin 46 to adopt a curved shape, and/or deformation of the pivot pins 58 and 60, as discussed above.

[0157] The fin 46 will typically be located in its folded position during installation of the filter element assembly 10 in a filter housing. Following location of the filter element assembly 10 in the housing with the fin disposed at the bottom of the element (considered in a circumferential sense and viewing along the assembly), the fin 46 can be manually rotated towards its deployed position, in which a transverse axis 74 of the fin (FIG. 6) is disposed substantially on a radius of the filter element 12, which radius intersects with its longitudinal axis 42.

[0158] As discussed above, the drainage promoter fin 46 may be of a polymeric material, and may be moulded, for example injection moulded. Suitable materials may include Nylon, ABS (Acrylonitrile Butadiene Styrene), Polypropylene and Acetal (POM, PolyOxyMethylene). Constructing the fin 46 from such materials may provide it with sufficient resilience/elastic deformability for it to be fitted to the filter element 12. Other materials and manufacturing techniques may however be suitable, including die casting using an aluminium or zinc alloy, for example.

[0159] In the illustrated embodiment, the fin 46 includes pivot pins 58 and 60, and pivot mounts 62 and 64 are provided on the filter element 12. It will be understood however that this arrangement may be reversed so that the fin 46 is provided with mounts, and the filter element with pivot pins. Equally, the fin 46 may be provided with one pivot pin and one pivot mount, for engaging a corresponding mount and pin on the filter element 12.

[0160] As discussed above, the drainage promoter 14 can readily be fitted to the filter element 12 and facilitates drainage of liquid contaminants from the gas stream flowing through the filter. The drainage promoter fin 46 is fitted to the end caps 24 and 26 of the filter element 12, which must carry appropriate fittings such as the pivot sockets 62 and 64. Dedicated end caps will therefore need to be manufactured, although it is conceivable that existing filter elements could be modified by mounting additional structure on its end caps, providing mountings for the connection features on the fin 46.

[0161] Turning now to FIG. 11, there is shown a front view of a filter element assembly in accordance with another embodiment of the present disclosure, the filter element assembly indicated generally by reference numeral 10a. The filter element assembly 10a comprises a filter element 12a and a drainage promoter 14a. Like components of the filter element assembly 10a with the filter element 10 shown in FIGS. 1 to 10 share the same reference numerals, with the addition of the suffix “a”.

[0162] The filter element 12a is of substantially the same construction as the filter element 12 shown in FIGS. 1 to 11 and described above. Accordingly, details of the construction and operation of the filter element 10a will not be described again in detail, reference instead being made to the discussion of the filter element 12 forming part of the filter element assembly 10 described above. Only substantial differences between the filter element assembly 10a and the assembly 10 will be described herein. In addition, the filter element assembly 10a can be located in a housing 4 of a filter 2 in a horizontal orientation in the same way as the filter element assembly 10. Reference will therefore be made to the discussion above concerning the way in which the filter element assembly 10a is located in a filter housing, and the way in which it operates during use.

[0163] The filter element assembly 10a is also shown in the end views of FIGS. 12 and 13, taken in the direction of the arrows A and B respectively in FIG. 11. FIG. 14 is a perspective view, and FIG. 15 a longitudinal cross-sectional view of the filter element assembly 10a, both drawn to a smaller scale.

[0164] In this embodiment, the drainage promoter 14a again comprises a fin 46a which is releasably connectable to the filter element 12a. The fin 46a is pivotable relative to the filter element 12a for connecting it to the element, the fin being shown in a connected position in FIGS. 11 to 15, and in a disconnected position in the side view of FIG. 16, during fitting of the fin to the filter element. The fin 46a is also shown separately in the front, end and perspective views of FIGS. 17, 18 and 19, the end view being taken in the direction of the arrow D in FIG. 17. The fin 46a is drawn to the same scale in FIGS. 17 and 19 as it is in FIG. 11 but is shown in a different orientation.

[0165] The filter element assembly 10a of FIGS. 11 to 19 differs from the filter element assembly 10 largely in relation to the way in which the fin 46a is connected to the filter element 12a. To this end, both the filter element 12a, and the fin 46a, include connection features which are different to those of the respective filter element 12, and fin 46.

[0166] In this embodiment, a pivoting connection is provided between the fin 46a and the filter element 12a which facilitates fitting of the fin to the filter element. The fin 46a has a first axial end 48a and a second axial end 50a. A first connection feature 58a is provided at the first axial end 48a, which is a male connection feature in the form of a pivot pin. The male connection feature 58a in fact comprises first and second pivot pin portions 76 and 78, which are generally cylindrical and have rounded heads. The pivot pin portions 76 and 78 are aligned along a transverse axis 80, which is disposed substantially perpendicular to a longitudinal axis 56a of the fin 46a. The first pivot pin portion 76 extends in a first lateral direction away from the longitudinal axis 56a, and the second pivot pin portion 78 in a second lateral direction.

[0167] The filter element end cap 24a comprises a first connection feature 62a in the form of a pivot socket or mount, which is a female feature that is shaped to receive the male connection feature defined by the pivot pin portions 76 and 78 on the fin 46a. The female pivot mount 62a on the first end cap 24a is best shown in the enlarged perspective detail view of FIG. 20, as well as the end views of FIGS. 12 and 13. The connection socket 62a includes a channel 82 which is shaped to receive the pivot pin portions 76 and 78, the channel being defined by a pair of curved arms 84 which extend from an outer perimeter 86 of the first end cap 24a. A slot 88 is defined between ends of the two arms 84, which is shaped to receive the fin 46 and communicates with the channel 82. The channel 82 has a closed end 90 (FIG. 20), which defines a detent for the pivot pin portions 76 and 78.

[0168] The fin 46a is connected to the filter element 12a by aligning the pivot pin portions 76 and 78 with the channel 82, as shown in FIG. 13. The pivot pin portions 76 and 78 can then be translated along the channel 82 until they come to rest at the closed end 90. The fin 46a is then in the position shown in FIG. 16 and can be pivoted about the transverse axis 80 of the pivot pin portions 76 and 78, by moving the second axial end 50a of the fin 46a in the direction of the arrow F in FIG. 16. The fin 46a can then be secured to the second end cap 26a at its second axial end 50a, to secure the fin to the filter element 12a.

[0169] Referring to FIG. 21, which is an enlarged detail view of the connection between the fin 46a and the second end cap 26a, the fin comprises a second connection feature 60a, which in this embodiment is a latch feature that provides a latching engagement with the second end cap 26a. The second end cap 26a comprises a second connection feature 64a, and the latch feature 60a on the fin 46a engages the latch feature 64a on the end cap 26a to secure the fin 46a to the filter element.

[0170] In the illustrated embodiment, the latch feature 60a on the fin 46a comprises a resiliently deformable latch arm 92 having a latch tooth 94. The latch feature 64a on the end cap 26a comprises a recess 96 which the latch tooth 94 of the latch arm 92 can engage in order to secure the fin 46a to the end cap 26a. A plurality of such recesses 96 may be provided in the end cap 26a, as shown in the end view of FIG. 13. This may facilitate orientation of the end caps 24a and 26a during manufacture of the filter element 12a, so that the connection features 62a and 64a can be aligned for receiving the fin connection features 58a and 60a.

[0171] When the fin 46a is pivoted from its disconnected position of FIG. 16 to its connected position of FIG. 21, the latch arm 92 comes in to contact with a chamfered surface 98 on the end cap 26a. The latch tooth 94 is similarly chamfered such that application of force to the fin 46a in the direction F causes the latch arm 92 to deform, so that the latch tooth 94 can pass along the chamfered surface and over an end surface of the end cap 26a, before latching into the recess 96 as shown in FIG. 21. The fin 46a is then connected to the filter element 12a.

[0172] The fin 46a also includes a recess 100 at its second axial end 50a, the recess being shaped to receive an outer peripheral portion 102 of the end cap 26a. When the peripheral portion 102 is located in the recess 100, the fin 46a is securely connected to the end cap 26a, constrained between end faces of the recess. A further resilient latch tooth 104 on the fin 46a snaps over an inner peripheral surface 106 of the end cap 26a, to provide an additional restraint against separation of the fin 46a from the filter element 12a. Engagement of the second axial end 50a of the fin 46a to the end cap 26a also acts to maintain engagement between the first axial end 48a of the fin and the first end cap 24a, because it prevents movement of the pivot pin portions 76 and 78 out of the channel 82 defined between the arms 84. When fitted to the filter element 12a, the fin 46a extends over the second end cap 46a, and partly over the first end cap 24a. A portion of the fin 46a including its base 52a is disposed between the end caps 24a and 26a and spans the distance between the end caps.

[0173] It will be understood that the orientation of the fin 46a relative to the filter element 12a may be reversed, with the pivoting connection provided at the second end cap 26a, and the latching connection at the first end cap 24a.

[0174] Turning now to FIG. 22, there is shown a front view of a filter element assembly in accordance with another embodiment of the present disclosure, the filter element assembly indicated generally by reference numeral 10b. The filter element assembly 10b comprises a filter element 12b and a drainage promoter 14b. Like components of the filter element assembly 10b with the filter element 10 shown in FIGS. 1 to 10 share the same reference numerals, with the addition of the suffix “b”.

[0175] The filter element 12b is of substantially the same construction as the filter element 12 shown in FIGS. 1 to 11 and described above. Accordingly, details of the construction and operation of the filter element 10b will not be described again in detail, reference instead being made to the discussion of the filter element 12 forming part of the filter element assembly 10 described above. Only substantial differences between the filter element assembly 10b and the assembly 10 will be described herein. In addition, the filter element assembly 10b can be located in a housing 4 of a filter 2 in a horizontal orientation in the same way as the filter element assembly 10. Reference will therefore be made to the discussion above concerning the way in which the filter element assembly 10b is located in a filter housing 4, and the way in which it operates during use.

[0176] The filter element assembly 10b is also shown in the end views of FIGS. 23 and 24, taken in the direction of the arrows A and B respectively in FIG. 22. FIG. 25 is a longitudinal cross-sectional view of the filter element assembly 10b, and FIG. 26 is a perspective view of the assembly, showing a fin 46b of its drainage promoter 14b prior to connection to the filter element 12b. The fin 46b is shown in its connected state in FIGS. 22 and 25, and in its disconnected state in FIG. 26, as mentioned above. FIGS. 26A, B and C are front views of the filter element assembly 10b showing successive steps in connection of the fin 46b to the filter element 12b.

[0177] In this embodiment, a sliding connection is provided between the fin 46b and the filter element 12b, the sliding connection being defined by connection features of the fin and the filter element. The connection features on the fin are shown in more detail in the enlarged front and end views of FIGS. 27 and 28, and the perspective view of FIG. 29, the end view taken in the direction of the arrow D in FIG. 27. The fin 46b is translatable relative to the filter element 12b between its disconnected position and its connected position. The fin 46b has a first axial end 48b and a second axial end 50b. A first connection feature 58b is provided at the first axial end 48b, and a second connection feature 60b at the second axial end 50b. The filter element 12b, in particular first and second end caps 24b and 26b of the filter element, define corresponding connection features 62b and 64b, which cooperate with the respective first and second connection features 58b and 60b on the fin 46b, so that the fin can be connected to the filter element end caps.

[0178] The second connection feature 60b on the fin 46b takes the form of a protrusion or projection which defines a key, and which takes the form of an elongate finger. The second connection feature 64b defined by the second end cap 26b defines a keyway in the form of a channel which is shaped to receive the key 60b of the fin 46b in a sliding fit. The key 60b has to be aligned with the keyway 64b in order for the features to be connected. This is best shown in the end view of FIG. 24.

[0179] The first connection feature 58b on the fin 46b similarly takes the form of a protrusion or projection defining a key. The first connection feature 62b defined by the first end cap 24b defines a keyway which similarly receives the key 58b in a sliding fit. Once again, the key 58b and the keyway 62b must be aligned for connection of the features. A restraint in the form of a shoulder 108 on the fin 46b proximate the key 60b acts to resist further translation of the fin relative to the filter element 12b, once the fin has been translated a sufficient distance relative to the filter element and adopted its connected position.

[0180] The key 58b defined by the fin 46b comprises key portions 110 and 112 which are aligned along a transverse axis 80b (FIG. 28) of the fin, the key portion 110 extending in a first lateral direction away from the fin, and the second key portion 112 in a second, opposite lateral direction. The key portions 110 and 112 are shaped to engage within a channel 114 of the keyway 58b on the first end cap 24b, which is defined by a pair of arms 116 and 118. The channel 114 tapers in a direction radially outwardly of the filter element 12b and the key portions 110 and 112 have a corresponding taper. This provides secure engagement of the key portions 110 and 112 within the channel 114 and acts to resist radial separation of the fin 46b from the first end cap 24b when connected. Latch teeth 120, 122 on the respective arms 116 and 118 engage on radially outer ledges 124, 126 of the respective key portions 110, 112 to restrain them in the channel 114.

[0181] The keyway 64b defined by the second end cap 26b is similarly tapered, as is the key 60b defined by the fin 46b. This acts to restrain the key 60b within the keyway 64b once the fin 46b has been connected to the filter element 12b. The key 60b also has a tapered leading end 128 which assists alignment with the keyway 64b during connection of the fin 46b. The leading end 128 defines a latch tooth 130 which can engage in a circumferential recess 132 (FIG. 25) defined on a lower end of the second end cap 26b. This acts to resist sliding movement of the fin 46b away from its connected position.

[0182] The keyways 62b and 64b on the end caps 24b and 26b, and the keys 58b and 60b defined by the fin 46b, must be aligned along an axis which is parallel to a longitudinal access 42b of the filter element 12b in order for connection of the fin to the element. The alignment axis is shown in the perspective view of FIG. 26 and given the reference numeral 134. In use, and once the fin 46b has been connected to the filter element 12b, a longitudinal axis 56b of the fin 46b resides on the alignment axis 134.

[0183] Fitting of the fin 46b to the filter element 12b is shown in the views of FIGS. 26A to C. As can be seen from FIG. 26A, a base 52b of the fin 46b has an axial length which is slightly smaller than an axial length L.sub.1 of the drainage layer 22b disposed between the filter end caps 24b and 26b. This allows the base 52b to be inserted between the end caps 24b and 26b, in contact with the drainage layer 22b. This is shown in FIG. 26B. The key 60b is aligned with the keyway 64b, and the key 58b with the keyway 62b, along the axis 134. The base 52b of the fin 46b has facing end surfaces, one of which is defined by the shoulder 108, and the other by a shoulder 136 (FIG. 29). The key portions 110 and 112 of the key 58b are spaced along a length of the fin 46b from the shoulder 136, defining an area 138 which can receive the arms 116 and 118 of the keyway 62b, so that the fin 46b can be located between the end caps 24b and 26b as shown in FIG. 26B. In this position, the key 60b is axially spaced from the keyway 64b on the second end cap 26b, and the key 58b is axially spaced from the keyway 62b on the first end cap 24b.

[0184] With the keys and keyways aligned as discussed above, the fin 46b can then be translated in the direction of the arrow G in FIG. 26C. This advances the key 60b into the keyway 64b, and the key 58b into the keyway 62b, so that they are located in their respective positions shown in FIG. 24 and FIG. 23 and described above. The latch tooth 130 engages in the circumferential recess 132 on the second end cap 26b, and a lip 140 adjacent the shoulder 108 on the fin 46b engages over an inner peripheral surface 106b (FIG. 25) of the second end cap 26b. When the fin 46b is connected to the filter element 12b, there is a small gap 142 between the shoulder 136 on the fin and the first end cap 24b. This gap enables fitting of the fin 46b between the end caps 24b and 26b, and the translational movement of the fin between its positions of FIG. 28 and FIG. 29.

[0185] As can best be seen from FIGS. 24 and 26, the second end cap 26b in fact comprises a plurality of keyways 64b, which are spaced around a circumference of the end cap. The provision of such a plurality of keyways 64b can aid manufacture of the filter element 12b. In particular and as discussed above, the filtration and drainage layers 20 and 22 of the filter element 12b, as well as other components such as the perforated support tubes 30b and 32b, are potted in the end caps 24b and 26b using a suitable adhesive. In order for the fin 46b to be fitted to the filter element 12b, the keyway 62b on the first end cap 24b must be aligned with a keyway 64b on the second end cap 26b. Providing the large number of keyways 64b spaced around the circumference of the second end cap 26b can simplify alignment with the keyway 62b during assembly.

[0186] When fitted to the filter element 12b, the fin 46b extends along the second end cap 26b, and partly over the first end cap 24b. A portion of the fin 46a including its base 52a is disposed between the end caps 24a and 26a and spans a majority of the distance between the end caps.

[0187] Turning now to FIG. 30, there is shown a front view of a filter element assembly in accordance with another embodiment of the present disclosure, the filter element assembly indicated generally by reference numeral 10c. The filter element assembly 10c comprises a filter element 12c and a drainage promoter 14c. Like components of the filter element assembly 10c with the filter element assembly 10 shown in FIGS. 1 to 10 share the same reference numerals, with the addition of the suffix “c”.

[0188] The filter element 12c and the drainage promoter 14c are in fact of very similar construction to the filter element 12b and the drainage promoter 14b of the filter element assembly 10b shown in FIGS. 22 to 29 and described above. In particular, the drainage promoter 14c comprises a fin 46c which is connected to the filter element 12c in a sliding connection, in the same way as the fin 46b is fitted to the filter element 12b. Reference is therefore made to the discussion of FIGS. 22 to 29 concerning the way in which the fin 46c is fitted to the filter element 12c.

[0189] The drainage promoter 14c is shown separately, disconnected from the filter element 12c, in the front, end and perspective views of FIGS. 31, 32 and 33. The drainage promoter fin 46c differs from the fin 46b in that it comprises a plurality of drainage elements 144 to 162, each of which is coupled to the fin 46c and extends in a direction away from the fin. The drainage elements 144 to 162 each take the form of a finger, rib, arm or the like, and are typically moulded integrally with the fin 46c. It will be understood however that the drainage elements 144 to 162 may be manufactured separately and subsequently connected to the fin 46c. The drainage elements 144 to 162 each extend in a direction around an outer surface of a drainage layer 22c of the filter element 12c, as shown in FIG. 30, and act to compress the drainage layer along their lengths, to further promote the drainage of liquid from the drainage layer and on to the fin 46c.

[0190] A first row or array of drainage elements 164 comprises drainage elements 144, 148, 152, 156 and 160, which each extend from the fin 46c in a first lateral direction, from a first flank 165 of the fin. A second row or array 166 comprises the drainage elements 146, 150, 154, 158 and 162 which each extend from the fin 46c in a second lateral direction, from a second flank 167 of the fin. The drainage elements in the arrays 164 and 166 each extend partway around a circumference of an external surface 44c of the drainage layer 22c when the drainage promoter 14c is fitted to the filter element 12c. The drainage elements 144 to 162 in the two rows 164 and 166 together act to promote drainage of liquid from a wet band or zone 170, which can form during use of the filter element 12c. Accordingly, the drainage element need only extend around part of the circumference of the drainage layer 22c in order to provide the enhanced drainage effect.

[0191] The drainage elements 144 to 162 are each disposed transverse to a longitudinal axis 56c of the fin and are suitably disposed substantially perpendicular to the fin axis, as can be seen in FIG. 31. It will be understood however that the drainage elements 144 to 162 may be oriented so that they are transverse to the fin axis 56c but at non-perpendicular angles. The drainage elements 144 to 162 are each curved, having inner surfaces which have a curvature that substantially matches a curvature of the external surface 44c of the drainage layer 22c, an inner surface of drainage element 144 being shown in FIG. 33 and given the reference numeral 172.

[0192] The drainage elements 144 to 162 each have a base at which they are coupled to the fin, a base 174 of the drainage element 146 being shown in FIG. 33. The drainage elements 144 to 162 each taper in a direction from their base towards a respective tip, the tip 176 of drainage element 146 being shown in FIG. 33. As can best be seen from FIG. 31, a width of each drainage element W.sub.1 at its base (shown for the drainage element 146 in FIG. 31) reduces in a direction towards its tip, to a width W.sub.2. An effective depth D.sub.1 of the drainage element 144 to 162 also reduces in a direction from its base 174 towards its tip 176, as again shown in FIG. 31. The reduced depth at the tip 176 can be appreciated from the perspective view of FIG. 33. Providing drainage elements 144 to 162 which taper in width and/or depth may help to promote the flow of liquid along the drainage elements and on to the fins 46c for subsequent discharge, during use of the drainage promoter 14c.

[0193] The drainage elements in the first row 164 are axially staggered along a length of the fin 46c relative to the drainage elements in the second row 166. This can best be seen from FIG. 31. Staggering the drainage elements in the first row 164 relative to the second row 166 can help to improve drainage of liquid from the drainage layer 22c in the wet band 170. It will be understood however that the drainage elements in the first and second rows 164 and 166 may be axially aligned, for example by arranging the elements in pairs at common axial positions. For example, and viewing FIG. 31, the drainage elements 144 and 146 may be arranged at a common axial position, and so aligned along a transverse axis of the fin 46c.

[0194] Whilst the drainage elements 144 to 162 have been shown on a fin 46c which is a sliding connection to its filter element 12c in the fashion of the fin 46b to the element 12b, it will be understood that similar such drainage elements may be provided on any of the other drainage promoters/fins disclosed in this document. By way of non-limiting example therefore, similar such drainage elements may be provided on the fin 46 of FIG. 1, and on the fin 46a of FIG. 11.

[0195] Turning now to FIG. 34, there is shown a front view of a filter element assembly in accordance with another embodiment of the present disclosure, the filter element assembly indicated generally by reference numeral 10d. The filter element assembly 10d comprises a filter element 12d and a drainage promoter 14d. Like components of the filter element assembly 10d with the filter element 10 shown in FIGS. 1 to 10 share the reference numerals, with the addition of the suffix “d”.

[0196] The filter element 10d is of substantially the same construction as the filter element 12 shown in FIGS. 1 to 11 and described above. Accordingly, details of the construction and operation of the filter element 10d will not be described again in detail, reference instead being made to the discussion of the filter element 12 forming part of the filter element assembly 10 described above. Any substantial differences between the filter element assembly 10d and the assembly 10 will be described herein. In addition, the filter element assembly 10d can be located in the housing 4 of a filter 2 in a horizontal orientation in the same way as the filter element assembly 10. Reference will therefore be made to the discussion above concerning the way in which the filter element assembly 10d is located in a filter housing 4, and the way in which it operates during use.

[0197] The filter element assembly 10d is also shown in the end views of FIGS. 35 and 36, taken in the direction of the arrows A and B respectively in FIG. 34. FIG. 37 is a perspective view and FIG. 38 a longitudinal cross-sectional view of the filter element assembly 10d, both drawn to a smaller scale.

[0198] In this embodiment, the drainage promoter 14d can be connected to a drainage layer 22d of the filter element 12d, rather than to first and second end caps 24d and 26d of the filter element 12d, in the way that the previously described drainage promoters are connected to their respective filter elements. The drainage promoter 14d is connected to the filter element 12d at a location between first and second end caps 24d and 26d of the filter element. A fin 46d of the drainage promoter 14d comprises connection features which serve for connecting the fin directly to the drainage layer 22d. In this case, the connection features take the form of resilient elements which are similar to the drainage elements 144 to 162 forming part of the drainage promoter 14c discussed above.

[0199] The drainage promoter 14d is shown separately in the front, end and perspective views of FIGS. 39, 40 and 41. A first array 164d of connection elements is provided, comprising connection elements 144d, 148d, 152d, 156d and 160d. A second row or array 166d comprises connection elements 146d, 150d, 154d, 158d and 162d. The connection elements 144d to 162d are of similar construction to the drainage elements 146 to 162 described above, and can also provide a drainage function, serving to enhance the flow of liquid from the drainage layer 22 to the fin 46d. However, a primary function of the connection elements 144d to 162d in this embodiment is to connect the fin 46d to the drainage layer 22d, and so to the filter element 12d.

[0200] The connection elements 144d to 162d each have a shape which is substantially similar to the drainage elements 144 to 162, tapering from a base 174d towards a tip 176d, which is shown for the connection element 144d in the end view of FIG. 40. In this embodiment however, the drainage elements 144d to 162d are arranged to impart a clamping force on the drainage layer 22d, for connecting the drainage promoter 14d to the filter element 12d. Specifically, the connection elements are arranged in pairs, axially adjacent connection elements (taken in a direction along a length of the fin 46d) acting together to provide the clamping force. A clamping force is therefore exerted between the connection elements 144d and 146d, as well as between successive pairs of connection elements along the length of the fin 46d. Thus, a clamping force is along exerted between the connection elements 146d and 148d, the connection elements 148d and 150d and so on. This is achieved by providing the connection elements as resilient arms, fingers or the like in a similar fashion to the drainage elements 144 to 162 described above.

[0201] In order to provide the clamping force, the connection elements 144d to 162d each extend from the fin 46d around a circumference of the filter element 12d to an over-centre position, relative to a central longitudinal axis 56d of the filter element 12d. A location of the central axis 56d, and the over-centre positioning of the connection elements 144d to 162d, is shown in the end view of FIG. 40. As can be seen, the pair of connection features 144d and 146d together encompass more than half of a circumference of the circular section drainage layer 22d, and so the filter element 12d. Effectively, the connection elements 144d to 162d together describe a generally cylindrical passage or opening 178 which is shaped to receive the filter element 12d. A space is defined between the ends 176 of the connection elements 144d to 162d, the space indicated generally by reference numeral 180 in FIG. 20. A dimension W.sub.2 of the space 180 is smaller than a diameter of the filter element 12d at its drainage layer 22d. This serves to provide the clamping force.

[0202] The drainage promoter 14c described above is typically moulded as a unitary or one-piece component, comprising its fin 46c and drainage features 144 to 162. The drainage promoter 14d can similarly be constructed as a unitary or one-piece structure, which would then require a push-fit of the drainage promoter to the drainage layer 22d. This would require that the space 180 defined between the tips 176 of the connection features 144d to 162d be opened up to pass around the drainage layer 22d, over its diameter to the over-centre position shown in FIG. 40.

[0203] It may therefore be preferable to construct the drainage promoter 14d as a two-piece structure, to facilitate fitting of the drainage promoter to the filter element 12d. This is best shown in the end view of the drainage promoter 14d in FIG. 42B, and the end view of the assembly in FIG. 42A, showing fitting of the drainage promoter to the filter element 14d. Referring to FIG. 42B, first piece 182 of the drainage promoter 14d comprises a first part 184 of its fin 46d and the first row 164d of connection features. A second piece 186 comprises a second part 188 of the fin 46d and the second row 166d of connection features. The first part 184 of the fin 46d defines a first flank 165d of the fin and a planar inner mating surface 190. The second part 188 of the fin 46d comprises a second flank 167d of the fin and a planar inner mating surface 192. The planar mating surface 190 is shown in the cross-sectional view of FIG. 38 and carries a number of mating protrusions 194 and mating apertures 196, the protrusions engaging in corresponding apertures (not shown) on the mating surface 192 and the apertures receiving corresponding mating protrusions 198 (one shown) on the mating surface 192. Engagement between the respective mating protrusions and apertures on the planar surfaces 190 and 192 serves for connecting the first and second pieces 182 and 186 of the fin together as shown in FIG. 40. The first fin piece 182 is typically fitted to the drainage layer 22d of the filter element 12d as shown in FIG. 42A, and then the other fin piece 186 is connected to the first fin piece, so that the connection features 144d to 162d clamp the drainage layer 22d.

[0204] When fitted to the filter element 12d, the fin 46d is disposed between the end caps 24d and 26d and spans a majority of the distance between the end caps.

[0205] Turning now to FIG. 43, there is shown a front view of a filter element assembly in accordance with another embodiment of the present disclosure, the filter element assembly indicated generally by reference numeral 10e. The filter element assembly 10e comprises a filter element 12e and a drainage promoter 14e. Like components of the filter element assembly 10e with the filter element assembly 10 shown in FIGS. 1 to 10 share the same reference numerals, with the addition of the suffix “e”.

[0206] The filter element 12e is of substantially the same construction as the filter element 12 shown in FIGS. 1 to 11 and described above. Accordingly, details of the construction and operation of the filter element 10e will not be described again in detail, reference instead being made to the discussion of the filter element 12 forming part of the filter element assembly 10 described above. Any substantial differences between the filter element assembly 10e and the assembly 10 will be described herein. In addition, the filter element assembly 10e can be located in a housing 4 of a filter 2 in a horizontal orientation in the same way as the filter element assembly 10. Reference will therefore be made to the discussion above concerning the way in which the filter element assembly 10e is located in a filter housing 4, and the way in which it operates during use.

[0207] The filter element assembly 10e is also shown in the end views of FIGS. 44 and 45, taken in the direction of the arrows A and B respectively in FIG. 43. In this embodiment, the drainage promoter 14e can be connected to the filter element 12e at a location between first and second end caps 24e and 26e of the filter element. The drainage promoter 14e can be connected to a drainage layer 22e, in a similar fashion to the drainage promoter 14d discussed above.

[0208] The drainage promoter 14e comprises a fin 46e and first and second connection elements 200 and 202 which can engage the drainage layer 22e, to connect the fin to the filter element. In the illustrated embodiment, the connection components 200 and 202 are spaced spart along a length of the fin 46e and are suitably provided at respective first and second axial ends 48e and 50e of the fin 46e. It will be understood however that the connection components 200 and 202 may be provided at alternative locations on the fin 46e, and/or that more than two connection components, or conceivably only a single connection component, may be provided.

[0209] The connection components 200 and 202 each take the form of a strap or tie which extends from the fin 46e and around a circumference of the drainage layer 22e. The drainage promoter 14e is shown separately in the front, end and perspective views of FIGS. 46, 47 and 48, which are drawn to a smaller scale, FIG. 47 viewing in the direction of the arrow D in FIG. 46.

[0210] The first strap 200 comprises a first strap portion 204 which extends in a first direction away from the fin 46e and around part of a perimeter of the drainage layer 22e, and a second strap portion 206 which extends in a second opposite direction away from the fin and around a further part of the perimeter of the drainage layer. The first and second strap portions 204 and 206 can be coupled together to connect the fin 46e to the filter element 12e. To this end, the strap portions 204 and 206 comprise respective connection features 205 and 207 which serve for coupling the portions together.

[0211] The first strap portion 204 comprises a female connection feature in the form of an aperture 205 formed in a stepped end section 209. The second strap portion 206 comprises a male connection feature in the form of a protrusion such as a button 207, which can be located within the aperture 205 in a press-fit, to secure the strap portions 204 and 206 together. The button 207 may include an enlarged head and may be resiliently deformable for passing through the aperture 205 and securing the strap portions 204 and 206 together. It will be understood that this represents just one option for the way in which the strap portions 204 and 206 can be coupled together. Alternatives can be envisaged, including a zip-tie type structure, a separate mechanical connection, or the use of an adhesive. The second strap 202 comprises similar such first and second strap portions 208 and 210 which also comprise connection features in the form of an aperture 212 and a button 214.

[0212] The straps 200 and 202 extend from the fin 46e to encompass the entire circumference of the drainage layer 22e, when their respective strap portions 204/206 and 208/210 are coupled together. In a variation however, a strap may be provided comprising a single portion which substantially encircles the drainage layer 22e, the strap being coupled at one end to the fin 46e and having a free end which can be connected to the fin after encircling the drainage layer. In a further variation, one or more straps may be provided separately, and may be connectable to the fin 46e to secure it to the filter element 12e, for example by passing through a locating aperture in the fin and around the drainage layer (or in an alternative, around an end cap).

[0213] FIGS. 49 and 50 are front and end views of the filter element assembly 10e shown during fitting of the drainage promoter 14e to the filter element 12b, drawn to a smaller scale. As shown in these drawings, the drainage promoter is introduced to the filter element 12e so that the fin 46e is positioned adjacent to the drainage layer 22e and located between the end caps 24e and 26e. The first strap portions 204 and 208 pass away from the fin 46e on one side of the fin, and the second strap portions 206 and 210 pass away from the other side of the fin. The strap portions 204 and 206 can then be brought together to encircle the drainage layer 22e, by bringing ends of the strap portions together in the direction of the arrows E and F shown in FIG. 50. The stepped end portion 209 on the first strap portion 204 can be located so that it passes over the button 207 on the second strap portion 206, and the button press-fitted through the aperture 205 to connect the two strap portions together. A similar procedure can then be followed for the strap portions 208 and 210 of the second strap 202.

[0214] Engagement of the strap portions 204, 206 and 208, 210 exerts a clamping force on the drainage layer 22e, causing the fin 46e to press into its external surface 44e, as shown in the longitudinal cross-sectional view of FIG. 51. The fitted drainage promoter 14e therefore adopts the position shown in the perspective view of FIG. 52. The connection straps 200 and 202 can also act to compress the drainage layer 22e, to provide improved drainage, in a similar fashion to the drainage elements discussed above.

[0215] When fitted to the filter element 12e, the fin 46e is disposed between the end caps 24e and 26e and spans the distance between the end caps.

[0216] Drainage promoters of the type disclosed in this document which can be connected to a drainage layer of a filter element (in particular the drainage promoters 14e and 14d) may provide the advantage that they can be connected to filter elements of a standard type, without necessarily requiring any modification to be made to the structure of the filter element, in particular its end caps. These and other drainage promoters disclosed in this document can provide the advantage that they can be removed from the filter element and connected to a further element, say in the situation where the filter element becomes clogged during use and requires replacement. This may provide material and cost benefits.

[0217] Various modifications may be made to the foregoing without departing from the spirit or scope of the present invention.

[0218] Numerous different embodiments of drainage promoters and filter elements to which the disclosed drainage promoters can be fitted are disclosed in this document. In further variations, the features of one or more of the disclosed embodiments may be provided in combination. Thus, for example, combinations of sliding and pivoting connection features, and connection features involving connection to a drainage layer rather than end caps of a filter element, may be provided in combination in further embodiments.

[0219] In each embodiment of filter element assembly disclosed in this document, either of the first and second end caps may comprise a port for the entry of gas into the filter element. In relevant embodiments, the fin may be connected differently to end caps of the filter element, for example in the embodiment of FIG. 11, the fin 46a may be pivotally connected to the second end cap 26a and may latch-fit to the first end cap 24a.

[0220] Reference is generally made in this document to a filter element comprising a wall of a filtration medium which defines a hollow space for a gas stream to flow from the space through the wall to be filtered, and a drainage layer located outside the filtration layer in which liquid separated from the gas stream can collect, as well as to a drainage promoter which compresses the drainage layer to promote drainage of liquid which has collected in the drainage layer. Reference may however be made generally to a fluid stream (which may not specifically be a gas), and to the drainage of fluid (which may not specifically be a liquid) which has collected in the drainage layer. The fluid which is collected in the drainage layer may have been filtered from the fluid stream flowing through the wall of the filter element. The fluid stream may therefore comprise a first fluid and at least one further fluid, which further fluid may collect in the drainage layer.