Filter element

Abstract

A filter element (2) is disclosed which comprises a filtration media (4) and an end fitting (6) through which a sealing connection is made between the filter element and a housing (100) so that, when the sealing connection is made, the end fitting defines in part a flow path for fluid between the housing and the filter element. The end fitting includes an annular seal (36′) made from a compressible material which extends around the periphery of the filter element, and a support (30, 31, 32, 34) for the annular seal which can be expanded outwardly to cause the transverse dimension of the seal to increase so that the seal is urged into contact with an inner wall of a housing (100) in which the filter element is located.

Claims

1. A filter element which comprises a filtration media and an end fitting through which a sealing connection is made between the filter element and a housing so that, when the sealing connection is made, the end fitting defines in part a flow path for fluid between the housing and the filter element, in which the end fitting includes: a) an annular seal made from a compressible material which extends around a periphery of the filter element, and b) a support for the annular seal which can be expanded outwardly to cause a transverse dimension of the annular seal to increase so that the annular seal is urged into contact with an inner wall of the housing when the filter element is located in the housing, in which the support has a periphery and a plurality of slits formed in the support which facilitate outward expansion of the support, the plurality of slits being arranged around the periphery of the support so that the support comprises a plurality of segments which can flex to allow the transverse dimension of the support to increase.

2. The filter element as claimed in claim 1, further including a sealing web which covers each slit of the plurality of slits to prevent flow of fluid through each slit of the plurality of slits.

3. The filter element as claimed in claim 2, in which the sealing web is formed as a part of the support.

4. The filter element as claimed in claim 2, in which the sealing web is provided as a deformable collar formed from an elastomeric material which covers each slit of the plurality of slits in the support.

5. The filter element as claimed in claim 4, in which the annular seal is an O-ring and in which the annular seal and the sealing web can be fitted on to and separated from the support as a single component.

6. The filter element as claimed in claim 1, in which the annular seal is an O-ring which is separate from the support.

7. The filter element as claimed in claim 6, in which the support defines a groove in an outer wall of the end fitting and in which the O-ring is received in the groove.

8. The filter element as claimed in claim 1, in which the annular seal is an O-ring which is formed as one piece with the support.

9. An assembly including the filter element as claimed in claim 1, in which the support has an opening, and an expander component which can be inserted into the opening to cause the support to expand outwardly.

10. The assembly as claimed in claim 9, in which the expander component closes the opening when the expander component is inserted into the opening.

11. The filter element as claimed in claim 1, in which: the support comprises a plurality of castellations formed in a side wall of the end fitting, the plurality of castellations defining a radially outwardly facing groove between a rib at top edges of the plurality of castellations and a remainder of the side wall extending from the plurality of castellations towards a bottom edge of the end fitting, a base surface of the radially outwardly facing groove being inclined inwardly towards the top edges of the plurality of castellations when the end fitting is in an undeformed configuration; and the annular seal is a sealing ring which extends around the end fitting in the radially outwardly facing groove.

12. A filter assembly which comprises a filter element and a housing, the housing having a cavity in which the filter element is received, the filter element includes a filtration media and an end fitting through which a sealing connection is made between the filter element and the housing so that, when the sealing connection is made, the end fitting defines in part a flow path for fluid between the housing and the filter element, in which the end fitting includes: a) an annular seal made from a compressible material which extends around a periphery of the filter element, and b) a support for the annular seal which can be expanded outwardly to cause a transverse dimension of the annular seal to increase so that the annular seal is urged into contact with an inner wall of the housing, in which the support has a plurality of slits formed in the support which facilitate outward expansion of the support, the plurality of slits being arranged around a periphery of the support so that the support comprises a plurality of segments which can flex to allow a transverse dimension of the support to increase, the inner wall of the housing is contacted by the annular seal when the transverse dimension of the annular seal has been increased.

13. The filter assembly as claimed in claim 12, in which the inner wall of the housing is provided by an additional filter element.

14. The filter element as in claim 1, wherein the annular seal is supported by the plurality of segments.

15. A filter element comprising a cylindrical filtration media and an end fitting at an end of the cylindrical filtration media through which a sealing connection is made, the end fitting defines in part a flow path for fluid between the housing and the filter element, the end fitting including: a) an annular support having at least one slit formed in the annular support which facilitates an outward expansion of the annular support, the at least one slit being arranged around the annular support to define at least one segment which can flex to allow a transverse dimension of the annular support to increase, the at least one segment defining a radially outwardly-facing groove around a periphery of the annular support, and b) an annular, compressible seal located within the radially outwardly-facing groove, wherein the annular support and the annular, compressible seal are configured such that the annular support can expand outwardly to cause a transverse dimension of the annular, compressible seal to increase so that the annular, compressible seal is urged into sealing contact with an inner wall of the housing when the filter element is located in the housing.

16. The filter element as claimed in claim 15, further including a sealing web covering each slit of the at least one slit to prevent flow of fluid through each slit of the at least one slit.

17. The filter element as claimed in claim 16, in which the sealing web is integral with the annular support.

18. The filter element as claimed in claim 16, in which the sealing web is a deformable, elastomeric collar covering each slit of the at least one slit in the annular support.

19. The filter element as claimed in claim 18, in which the annular, compressible seal is an O-ring and in which the annular, compressible seal and the sealing web can be fitted on to and separated from the annular support as a single component.

20. The filter element as claimed in claim 15, in which the annular, compressible seal is an O-ring.

21. The filter element as claimed in claim 15, in which: the annular support comprises a plurality of castellations formed in a side wall of the end fitting, the plurality of castellations defining the radially outwardly facing groove between a rib at top edges of the plurality of castellations and a remainder of the side wall extending from the plurality of castellations towards a bottom edge of the end fitting, a base surface of the radially outwardly-facing groove being inclined inwardly towards the top edges of the plurality of castellations when the end fitting is in an undeformed configuration; and the annular, compressible seal is a sealing ring which extends around the end fitting in the radially outwardly-facing groove.

22. The filter element as in claim 15, wherein the annular, compressible seal is supported by the at least one flexible segment.

23. The filter element as in claim 15, wherein the annular support projects outwardly away from an end face of the fitting.

24. The filter element as in claim 15, wherein the annular support includes a plurality of slits arranged around the periphery of the annular support, and which define a plurality of segments that can flex to allow the transverse dimension of the annular support to increase.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Filter elements, filter assemblies and components thereof are described below by way of example with reference to the accompanying drawings, in which:

(2) FIG. 1 is a side elevation of a filter element.

(3) FIG. 2 is an isometric cut-away view of the filter element shown in FIG. 1, showing the end fittings and an outer cylindrical wall of a pleated filter media material.

(4) FIG. 3 is an isometric view of the top end fitting of the filter element shown in FIG. 1.

(5) FIG. 4 is an isometric cut-away view of the top end fitting shown in FIG. 3, in which a sealing web in the form of a deformable collar has been applied to the base of an annular groove which extends around the end fitting.

(6) FIG. 5 is a sectional elevation through an upper portion of a filter assembly which includes a filter element as shown in FIG. 1, with an expander component in the form of a closing lid for the housing in position to be pressed on to the end fitting to cause the end fitting to expand.

(7) FIG. 6 is a sectional elevation through the upper portion of the filter assembly as shown in FIG. 5, with the closing lid for the housing pressed on to the end fitting, to cause the end fitting to expand.

DETAILED DESCRIPTION

(8) Referring to the drawings, FIGS. 1 and 2 show a filter element 2 which can be used to filter a fluid so as to remove contaminants from the fluid. The element can be used to remove contaminants from a liquid. The contaminants can be in the form of solid particles. The contaminants can be in the form of droplets of an immiscible liquid. The fluid might be a fuel, such as a liquid hydrocarbon, and the filter can then be used in the removal of aqueous contaminants.

(9) The filter element 2 has a cylindrical wall 4 which is formed from a paper filter media by pleating. The filter element has a top end fitting 6 and a bottom end fitting 8. Each of the end fittings has an outer groove formed in it in which an end face 10 of the cylindrical wall 4 is received. The outer groove 14 in the top end fitting faces downwardly, towards the bottom end fitting. The outer groove 16 in the bottom end fitting faces upwardly, towards the top end fitting.

(10) The top end fitting has a downwardly facing inner groove 12 located radially inside the outer groove 10. The inner groove is defined inwardly by a shallow cylindrical wall 13 which defines a central core socket 58. The inner groove can receive an inner layer of a filter media material or a support core or both. For example, the filter element can include a layer of a coalescer material such as a coalescer foam. The filter element can include a support core, for example provided by a perforated cylinder formed from metal sheet or by a porous support which is formed from a polymeric material, for example by moulding. Such additional components of the element are not shown in FIGS. 1 and 2.

(11) The bottom end fitting 8 has an outwardly facing groove 20 which can receive a compressible O-ring seal. An O-ring in the groove of the external wall of the bottom end fitting 8 forms a seal with an internally facing portion of the outer cylindrical wall of a filter housing when the filter element is in its in-use position within the housing.

(12) The top end fitting 6 is shown in greater detail in FIGS. 3 and 4. The fitting has a plurality of castellations 30 formed in its side wall 31. The top edge of each of the castellations is chamfered on its inwardly facing surface (as can be seen in FIGS. 5 and 6). A radially outwardly facing groove 32 is defined by the castellations between a rib 34 at the top edges of the castellations and the remainder of the wall extending from the castellations towards the bottom edge of the top end fitting. The base surface of the groove 32 is inclined inwardly towards the top edges of the castellations when the top end fitting is in its undeformed configuration, as shown in FIG. 3. The portion of the side wall of the top end fitting between the castellations 30 and the bottom edge of the fitting is approximately cylindrical.

(13) FIGS. 3 and 4 show a sealing ring 36 which extends around the top end fitting in the groove 32. The sealing ring is formed by moulding. For example, the sealing ring can be formed by moulding in situ within the groove 32 in the top end fitting. The sealing ring within the groove has a generally flat cross-section. The material of the sealing ring also fills the gaps 37 between adjacent castellations, preferably so that it is bonded to the sides of the castellations where they face towards one another. The material of the sealing ring is capable of elastic deformation. Use of a deformable material for the sealing ring means that the sealing ring material can remain bonded to the sides of the castellations when the sides move apart slightly due to flexing of the castellations, for example when the castellations are deformed outwardly by being bent about their bottom edges.

(14) The end fittings 6, 8 of the filter element 2 can be formed from a polymeric material by moulding. Suitable polymeric materials include polyolefins, polyamides, polyesters, polycarbonates and the like. A polymeric material from which an end fitting is formed by moulding can include a reinforcing component, for example reinforcing fibres.

(15) The top end fitting 8 has three extending upwardly tangs 50. Each of the tangs has an outwardly facing barb 51. The tangs are capable of flexing radially.

(16) The top end fitting 32 has eight ribs 52 which extend radially outwardly from the centre of the top face of the end fitting. Each of the ribs has a tall portion close to the axis of the end fitting. The tall portions of the ribs effectively define a central turret having eight sides.

(17) The top end fitting 32 has a pair of channels 42 which extend radially from openings 44 in the side wall of the end fitting, communicating at their inner ends with the central core socket 58 defined by the shallow cylindrical wall 13.

(18) FIGS. 5 and 6 show an upper portion of a filter assembly which includes a filter element generally as discussed above with reference to FIGS. 1 to 4. The filter assembly includes a housing which is provided by a hollow cylindrical housing body 100 and a housing lid 102. The housing is configured so that the filter element can be fitted within the cylindrical space defined by the housing body and the housing lid. The housing has a base which includes an inlet port and an outlet port for the fluid which is filtered within the filter assembly. The housing base provides a cylindrical socket in which the bottom end fitting of the filter element can be received, in such a way that an O-ring located in the groove 20 in the bottom end fitting 8 of the filter element is compressed against the cylindrical surface provided by the socket when the filter element is in its in-use position within the housing.

(19) The housing base includes a drain through which collected contaminants (especially liquid contaminants) can be removed from the filter assembly. Features of the housing base are not shown in the drawings. They are commonplace in known filter assemblies as used to filter fluids such as gases (for example compressed air) and liquids (for example to remove oil contaminants from water and to remove water contaminants from liquid hydrocarbons).

(20) In the filter assembly which is shown in FIGS. 5 and 6, the filter element 2 has a sealing ring located in the groove 32 in the top end fitting 6 which is in the form of an O-ring 36′ with a circular cross-section. The filter element is shown with a layer 38 of a coalescing foam located in the downwardly facing inner groove 12 of the top end fitting, together with a foraminous support element 40. A support component can be made from a polymeric material such as a polyolefin or a polyester or a polyamide. A support component can be made conveniently by moulding.

(21) The housing lid 102 is circular with a radius which is sufficient for it to cover the upper edge of the cylindrical housing body 100. The housing lid has three downwardly extending tangs 110. Each of the tangs has an inwardly facing barb 111. The tangs are capable of flexing radially. The spacing between the tangs on the housing lid matches that of the tangs on the upper end cap so that the barbs on the housing lid and the end cap can engage one another.

(22) The housing lid has a downwardly extending actuator flange 112. The bottom edge of the actuator flange is chamfered on its outwardly facing surface (as can be seen in FIGS. 5 and 6). The radius of the outside surface of the actuator flange 112 on the housing lid is approximately equal to the radius of the internal surface of the cylindrical portion of the side wall 31 of the upper end fitting which extends downwardly from the castellations 30.

(23) The housing lid has a central cavity 114 whose cross-section is approximately octagonal. The cavity in the housing lid can receive the turret which is defined by the tall portions of the ribs 52 on the top end fitting when the lid is fitted on to the top end fitting.

(24) Assembling the Filter Element in the Housing

(25) An initial step in the assembly of the filter involves locating the filter element 2 in the housing body 100. This involves the bottom end fitting 8 being received within the cylindrical socket in the housing base so that an O-ring located in the groove in the bottom end fitting 8 of the filter element is compressed against the cylindrical wall that is provided by the socket. FIG. 5 shows the filter element when it is partially inserted into the housing and FIG. 6 shows the filter element fully inserted into the housing.

(26) When the filter element 2 is fully inserted into the housing body 100, with the bottom end fitting 8 fully received in the cylindrical socket, the top end fitting 6 is located largely within the housing body at its open end so that the groove 32 in the top end fitting, and the sealing O-ring 36′ in the groove, are located below upper edge of the housing body 100. The filter element is shown in this position within the housing body in FIG. 6.

(27) The castellations 30 in the side wall of the top end fitting 6 are inclined inwardly during the step of positioning the filter element in the housing body. The external diameter of the top end fitting as defined by the sealing ring 36′ is less than the internal diameter of the opening into the space that is defined by the top edge of the cylindrical wall of the housing body.

(28) The housing lid 102 is positioned on the top of the housing body. The barbed tangs 110 on the housing lid are aligned with the barbed tangs 50 on the top end fitting 6 of the filter element 2. The tangs 50, 110 deform to enable the barbs 111 on the lid tangs 110 to pass the barbs 51 on the end fitting 50 as the lid is pressed on to the housing body. This results in the tangs 110 on the lid becoming engaged with the tangs 50 on the end fitting. The ribs 52 on the top end fitting 6 are received in the central cavity 114 in the housing lid. The engagement between the edges of the ribs and the walls of the octagonal cavity help to locate the lid relative to the filter element rotationally.

(29) Continued movement of the housing lid 102 towards the filter element 2 causes the downwardly extending actuator flange 112 on the lid to engage the chamfered top edge of the side wall of the top end fitting of the filter element, which is provided by the castellations 30. The outer diameter of the actuator flange on the housing lid is less than the internal diameter of the side wall of the top end fitting at its top edge. The movement of the housing lid causes the castellations which make up the side wall of the top end fitting to deform outwardly, by a bending deformation about the bottom edges of the castellations. The deformation of the castellations causes the distance between adjacent castellations to increase. The result of the deformation is that the external diameter of the upper end cap in the region of the castellations increases, so that the sealing ring 36′ which is provided in the groove 32 in the external walls of the castellations comes into contact with the inner cylindrical wall of the housing body. An annular space 106 between the cylindrical wall 4 of the filter element 2 and the internal wall of the housing body 100 is sealed at the top end of the housing by means of the sealing ring 36′.

(30) It is an advantage that the sealing ring has a reduced diameter when the filter element is introduced into the housing body because the sealing ring is not forced into sealing contact with the relevant counter-surface during the introduction. This can help to reduce the risk of damage to the sealing ring during the introduction. The separation of the introduction and the formation of a seal can also help to reduce the risk of a filter element not being introduced fully into a filter housing.

(31) The deforming interaction between the housing lid and the side wall of the top end fitting of the filter element is facilitated by the chamfer on the top edge of the side wall. A chamfer might be provided on the actuator flange on the lid, in addition to or instead of the chamfer on the top edge of the side wall.

(32) The housing lid can be fastened to the housing body once the lid and the inner filter element are fully seated. For example, the housing lid might be fastened to the housing body by bayonet features, for example in which a bayonet lug is provided on the housing lid which is received in a bayonet slot on the housing body. A separate component such as a fastener band might be used to fasten the housing lid to the housing body.

(33) Use of the Filter Assembly

(34) The assembled filter assembly with the filter element 20 within the housing 100 defines flow paths for the process fluid. A first flow path extends from a fuel inlet in the housing body to the annular space between the internal surface of the cylindrical wall of the housing body and the external surface of the cylindrical wall 4 of the filter element 2.

(35) Fluid which is supplied to the annular space 106 between the internal surface of the cylindrical wall of the housing body and the filter element flows through the media layers 4, 38 of the filter element. The support element 40 supports the media layers against the pressure of the fluid flowing through it. Contaminants (for example particulate contaminants, and water based liquid contaminants when the process fluid is a hydrocarbon fuel) collect on the media.

(36) Fluid which has flowed through the media layers 4, 38 of the filter element 2 flows into the cylindrical cavity within the filter element, defined at its upper end by the core socket 58 provided by the top end fitting 6. The filtered fluid within the cylindrical cavity in the filter element is discharged from the filter assembly through an outlet in the housing base. Such flow path arrangements for fluid in a filter assembly are known from existing filter assemblies.

(37) Gases (especially air) which are entrained in fluid flowing through the filter are separated initially from the fluid at the filter element 2. Such gases tend to collect in the annular space between the internal surface of outer cylindrical wall 120 of the housing body 100 and the external surface of the cylindrical wall 4 provided by the paper filter media material of the filter element, at the top of that space. Collected gases can flow through the channels 42 in the upper end cap 6 of the filter element 2 to the central core socket 58. Collected gases can be vented to atmosphere.

(38) Separating the Filter Element from the Housing

(39) The filter element requires replacement when accumulated contaminants cause the pressure drop across the element to increase beyond a pre-determined threshold. Such operating requirements apply conventionally to existing filters. In a filter assembly such as that shown in the drawings, the housing lid can be separated initially from the housing body, for example by detaching the rib and slot features of a bayonet connection or removing a separate fastening strap. The housing lid can then be lifted from the housing body and from the inner and outer filter elements. This involves the actuator flange 112 on the housing lid separating from the upper end cap of the filter element so that the outwardly deformed castellations 30 can relax inwardly, and so that the sealing ring 36′ in the groove 32 in the external walls of the castellations can separate from the cylindrical wall of the housing body.

(40) Continued separation of the housing lid from the housing body causes the barbed tangs 50 on the top end fitting 6 of the filter element 2 to engage the barbed tangs 110 on the housing lid 102 so that the filter element is withdrawn from within the housing. The filter element can then be separated from the housing lid and replaced. It is an advantage that the operator does not need to touch the filter element during the step of removing it from within the housing.

(41) In a variation of the disclosed embodiment, the support may be continuous around the periphery of the filter element and made from a material which can be deformed to allow the support to expand outwardly.