Claims
- 1. A cartridge filter comprising:
a housing body; a sump releasably attached to the housing body; and a filter cartridge within the housing body releasably attached to the housing body by a screw connection that is separate from the connection of the sump to the housing.
- 2. A cartridge filter according to claim 1, wherein said screw connection comprises screw thread formations on said filter cartridge and on said housing body.
- 3. A cartridge filter according to claim 2, wherein said screw thread formations comprise a plurality of screw thread formations evenly spaced about a circumference of each of said filter cartridge and said housing body.
- 4. A cartridge filter according to claim 3, wherein said circumference is a circumference of a tubular formation providing communication for fluid flow between said housing body and an interior space of said filter cartridge.
- 5. A cartridge filter according to claim 3, wherein said screw formations define sloped surfaces that slide over each other when the connection is being screwed up or unscrewed, and axially-facing surfaces that rest on each other when the connection is in a fully-engaged condition.
- 6. A cartridge filter according to claim 5, wherein said screw thread formations on one of said filter cartridge and said housing body comprise projections having a said sloped surface and a said axially-facing surface of comparable length.
- 7. A cartridge filter according to claim 6, wherein said screw thread formations that comprise projections are largely bounded by two opposite sloped surfaces and two opposite axially-facing surfaces of comparable length.
- 8. A cartridge filter according to claim 3, wherein said screw thread formations on at least one of said filter cartridge and said housing body comprise axially-extending surfaces against which said screw thread formations on the other of said filter cartridge and said housing body stop when the connection is fully engaged.
- 9. A cartridge filter according to claim 2, wherein said housing body comprises an adapter for said cartridge, and said screw thread formations on said housing body are on said adapter.
- 10. A cartridge filter according to claim 1, wherein said connection between said sump and said housing body comprises a screw connection.
- 11. A cartridge filter according to claim 10, wherein said screw connection between said sump and said housing body comprises:
on one of said sump and said housing body, a first screw formation having a sloped screw surface and, at the end that is leading with respect to tightening of the connection, a lug projecting above said sloped screw surface; on the other of said sump and said housing body, a second screw formation having a sloped screw surface along which said lug can run as said screw connection is being tightened and an end at the end that is trailing with respect to tightening of the connection; and on the other of said sump and said housing body, a feature positioned to engage the leading end of said first screw formation and to deflect said lug over the trailing end of said second screw formation.
- 12. A cartridge filter according to claim 11, wherein said lug is secured between said feature and said second screw formation.
- 13. A cartridge filter according to claim 11, wherein said lug has a running surface parallel to said sloped screw surface of said first screw formation.
- 14. A cartridge filter according to claim 11, wherein said lug has a sloped trailing end and said trailing end of said second screw formation is correspondingly sloped at an angle such that when said lug is over said trailing end a rotational force in the unscrewing sense can cause said sloped ends to slide over one another, lifting said lug onto said sloped screw surface of said second screw formation.
- 15. A cartridge filter according to claim 11, comprising equal pluralities of said first screw formations, said second screw formations, and said features.
- 16. A cartridge filter according to claim 15, wherein each said feature is so positioned that, when said lugs are resting on the leading ends of said sloped screw surfaces of said second screw formations, said projections form a running clearance with back surfaces of said first screw formations.
- 17. A filter cartridge for use in a cartridge filter having a housing body and a sump releasably attached to the housing body and enclosing the cartridge, the cartridge comprising: an end with screw thread formations for engagement with corresponding screw thread formations on a housing body of said filter.
- 18. A filter cartridge according to claim 17, wherein said screw thread formations comprise a plurality of screw thread formations evenly spaced about a circumference of said filter cartridge.
- 19. A filter cartridge according to claim 17, wherein said screw thread formations define sloped surfaces that are arranged to slide over correspondingly sloped surfaces of said housing body when the connection is being screwed up or unscrewed, and axially-facing surfaces that are arranged to rest on corresponding axially-facing surfaces of said housing body when the connection is in a fully-engaged condition.
- 20. A housing body for a cartridge filter, comprising:
a receptacle with screw thread formations for engagement with corresponding screw thread formations in a filter cartridge of said filter; and formations for engaging a sump of said filter surrounding said cartridge, independently of said screw connection with said cartridge.
- 21. A housing body according to claim 20, wherein said screw thread formations comprise a plurality of screw thread formations evenly spaced about a circumference of each of said housing body and said cartridge.
- 22. A housing body according to claim 21, wherein said circumference of said housing body is a circumference of a tubular formation providing communication for fluid flow between said housing body and an interior space of said filter cartridge.
- 23. A housing body according to claim 20, wherein said screw formations define sloped surfaces over which correspondingly sloped surfaces on said cartridge are arranged to slide when the connection is being screwed up or unscrewed, and axially-facing surfaces on which corresponding axially-facing surfaces of said cartridge are arranged to rest when the connection is in a fully-engaged condition.
- 24. A housing body according to claim 23, wherein said screw thread formations comprise axially-extending surfaces against which corresponding screw thread formations on said filter cartridge are arranged to stop when the connection is fully engaged.
- 25. A screw connection comprising:
a first component having a first screw formation with a bearing surface and, at the end that is leading with respect to tightening of the connection, a lug projecting from said sloped screw surface; and a second component having:
a second screw formation with a sloped screw surface along which said lug can run as said screw connection is being tightened and an end at the end that is trailing with respect to tightening of the connection; and a projection positioned to engage the leading end of said first screw formation and to deflect said lug over the trailing end of said second screw formation.
- 26. A screw connection according to claim 25, wherein said lug is secured between said projection and said second screw formation.
- 27. A screw connection according to claim 25, wherein said lug has a running surface that, when the screw connection is being screwed up, is parallel to and runs on the sloped screw surface of said first screw formation.
- 28. A screw connection according to claim 25, wherein said lug has a sloped trailing end and said trailing end of said second screw formation is correspondingly sloped at an angle such that when said lug is over said trailing end a rotational force in the unscrewing sense can cause said sloped ends to slide over one another, lifting said lug onto said sloped screw surface of said second screw formation.
- 29. A screw connection according to claim 25, comprising equal pluralities of said first screw formations, second screw formations, and projections.
- 30. A screw connection according to claim 29, wherein each said projection is so positioned that, when said lugs are resting on the leading ends of said sloped screw surfaces of said second screw formations, said projections form a running clearance with back surfaces of said first screw formations.
- 31. A screw connection comprising a first member and a second member having lugs and screw threads so arranged that when the screw connection is engaged each lug engages a screw thread, wherein each lug has an angled surface and an axially-facing surface, and each screw thread has an angled surface that when the screw connection is engaged aligns with the angled surface of one of the lugs, an axially-facing surface, and an axially extending stop, and wherein when the screw connection is fully tightened the lugs rest on the axially-facing surfaces of the screw threads and against the stops.
- 32. A cartridge filter comprising:
a body; and a sump removably attachable to the body and arranged to enclose a cartridge; wherein the body is provided with a screw connector arranged to engage a corresponding screw connector on the cartridge so as to retain the cartridge on the body when the sump is removed.
- 33. A cartridge filter according to claim 32, wherein the body is provided with an adapter for the cartridge and the screw connector is on the adapter.
- 34. A cartridge filter according to claim 32, wherein the sump and the body are provided with screw connectors for attaching the sump to the body.
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Application No. 60/472,848, filed May 23, 2003.
Provisional Applications (1)
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Number |
Date |
Country |
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60472848 |
May 2003 |
US |