Self cleaning reciprocating and/or rotating device

- Roper Holdings, Inc.

A cylinder and sleeve combination, such as those found in fluid control devices, having closely positioned moving elements that leach one or more substances upon sustained contact with the subject, reactive fluid. One embodiment comprises a metering pump which utilizes small clearances that were heretofore unacceptably tight for the applications disclosed. The materials used to form at least one of the moving elements allow a substance to leach out of the moving elements as a result of a chemical reaction with the fluid, and the leached substance undergoes a separate reaction with the fluid which causes it to coagulate. The various embodiments of the present invention avoid binding of the moving elements by providing at least one scraping edge which continuously scrapes away the coagulum forming between these elements. The scraping edge is advantageously configured so as not to interfere with the operative movement of these elements.

Skip to:  ·  Claims  ·  References Cited  · Patent History  ·  Patent History

Claims

1. A fluid control system for controlling the movement of a fluid from a fluid source to a fluid outlet comprising:

means for supplying a reactive fluid comprising a reactive fluid;
a substantially hollow sleeve, said sleeve comprising a control portion and a journal portion, said control portion comprising at least one inlet and at least one outlet, wherein said inlet is in fluidic communication with said supplying means;
a piston comprising a control portion and a journal portion, wherein said piston is movably supported at least partially within said sleeve such that said sleeve overlaps said piston forming a contact area and wherein said piston controls the flow of fluid within said control portion, said journal portion of said piston having a generally cylindrical cross-section with an outer diameter dimensioned to form a gap with a clearance of less than 0.0005 inches between said journal portion of said piston and said journal portion of said sleeve;
wherein at least one of said piston or said sleeve comprises a leachable substance which migrates out of said piston or said sleeve and coagulates in said gap upon sustained contact with said fluid thereby forming a coagulum and decreasing said clearance between said sleeve and said piston and tending to bind said piston to said sleeve;
at least one of said piston or said sleeve further comprising a scraping surface which moves across at least a portion of said journal portion to scrape said coagulum from said gap.Iadd., said journal portion not comprising rinse ports for the removal of said coagulum.Iaddend..

2. A fluid control device according to claim 1 wherein said piston comprises an alumina ceramic.

3. A fluid control device according to claim 2 wherein said leachable material is present in said piston and said leachable material comprises calcium.

4. A fluid control device according to claim 2 wherein said sleeve comprises an alumina ceramic.

5. A fluid control device according to claim 4 wherein said leachable material is present in said sleeve and said leachable material comprises calcium.

6. A fluid control device according to claim 1 wherein said sleeve comprises an alumina ceramic.

7. A fluid control device according to claim 6 wherein said leachable material is present in said sleeve and said leachable material comprises calcium.

8. A fluid control device according to claim 1 wherein said scraping surface forms a scraping angle of at least 45.degree..

9. A fluid control device according to claim 1 wherein said scraping edge moves over at least 50% of said contact area.

10. A fluid control device according to claim 1 wherein said clearance is less than 0.0002 inches.

11. A fluid control device according to claim 1 wherein said clearance is less than 0.0001 inches.

12. A fluid metering device for pumping a fluid from a fluid source to a fluid outlet comprising:

a substantially hollow sleeve, said sleeve comprising a pumping portion and a journal portion, said pumping portion comprising at least one inlet and at least one outlet;
a piston comprising a pumping portion and a journal portion, wherein said piston is movably supported at least partially within said sleeve such that said journal portion of said sleeve overlaps said journal portion of said piston forming a contact area, and wherein said pumping portion of said piston displaces a fluid within said pumping portion of said sleeve, said journal portion of said piston comprising a generally cylindrical cross-section with an outer diameter dimensioned to provide a clearance of less than 0.0005 inches between said journal portion of said piston and said journal portion of said sleeve;
wherein at least one of said piston or said sleeve comprises a ceramic comprising a leachable substance which migrates out of said ceramic and coagulates in said clearance upon sustained contact with said fluid thereby forming a coagulum and tending to bind said piston to said sleeve;
at least one of said piston or said sleeve further comprising a scraping edge which moves across a portion of said contact area to scrape said coagulum from said gap.Iadd., said journal portion not comprising rinse ports for the removal of said coagulum.Iaddend..

13. A fluid metering device for pumping a fluid from a fluid source to a fluid outlet according to claim 12 wherein said clearance is not greater than 0.0002 inches.

14. A fluid metering device for pumping a fluid from a fluid source to a fluid outlet according to claim 12 wherein said clearance is less than 0.0001 inch.

15. A fluid metering device for pumping a fluid from a fluid source to a fluid outlet according to claim 12 wherein said scraping edge moves across at least 25% of said contact area.

16. A fluid metering device for pumping a fluid from a fluid source to a fluid outlet according to claim 12 wherein said scraping edge moves across at least 75% of said contact area.

17. A fluid metering device for pumping a fluid from a fluid source to a fluid outlet according to claim 12 wherein:

said sleeve and said piston are formed of an alumina ceramic and wherein said sleeve comprises a greater proportion of calcium than said piston;
said clearance is less than 0.0015 inches;
said leachable substance comprises a form of calcium; and
said scraping edge moves across at least 75% of said contact area and forms a scraping angle of at least 45.degree..

18. A cylinder-sleeve combination operating in the presence of a reactive fluid comprising:

a reactive fluid;
a substantially hollow sleeve;
a cylinder movably supported at least partially within said sleeve such that said sleeve overlaps at least a portion of said cylinder to define a contact area, said cylinder having an outer diameter dimensioned to provide a gap having a clearance of less than 0.0005 inches between said cylinder and said sleeve in said contact area;
wherein at least one of said cylinder or said sleeve is formed of a material comprising a leachable substance which migrates out of said cylinder or said sleeve and coagulates in said gap upon sustained contact with said reactive fluid thereby forming a coagulum and decreasing said clearance between said sleeve and said cylinder and tending to bind said cylinder to said sleeve;
at least one of said cylinder or said sleeve further comprising a scraping edge which move across a portion of said contact area to scrape said coagulum from said gap.Iadd., said journal portion not comprising rinse ports for the removal of said coagulum.Iaddend..

25. A fluid control device according to claim 18 wherein said clearance is less than 0.0002 inches.

26. A fluid control device according to claim 18 wherein said clearance is less than 0.0001 inches.

27. A fluid control device according to claim 18 wherein said clearance is less than 0.00005 inches..Iadd.28. A valveless, positive displacement pump for controlling the movement of a fluid from a fluid source to a fluid outlet comprising:

a substantially hollow sleeve;
a piston movably supported at least partially within said sleeve such that said sleeve overlaps at least a portion of said piston, said piston having an outer diameter dimensioned to provide a gap having a clearance of less than 0.0005 inches between said piston and said sleeve in said overlap area;
means for supplying fluid, said fluid comprising at least one component which will coagulate on the surface of at least one of said sleeve or said piston and decrease said clearance between said sleeve and said piston and tending to bind said piston to said sleeve;
said sleeve comprising a control portion and a journal portion, said control portion comprising at least one inlet and at least one outlet, wherein said inlet is in fluidic communication with said supplying means;
said piston further comprising at least one groove which extends entirely around the circumference of said piston forming a scraping edge which moves across a portion of said contact area to scrape said coagulum from said gap..Iaddend..Iadd.29. A valveless, positive displacement pump according to claim 28 comprising a plurality of spaced grooves extending

entirely around the circumference of said piston..Iaddend..Iadd.30. A valveless, positive displacement pump according to claim 28 wherein said journal portion of said sleeve does not comprise rinse ports for the removal of said coagulum..Iaddend..Iadd.31. A valveless, positive displacement pump according to claim 28 wherein said clearance is less than 0.0002 inches..Iaddend..Iadd.32. A valveless, positive displacement pump according to claim 28 wherein said clearance is less than 0.0001 inches..Iaddend..Iadd.33. A valveless, positive displacement pump according to claim 28 wherein said clearance is less than 0.00005 inches..Iaddend..Iadd.34. A valveless, positive displacement pump according to claim 28 wherein said scraping edge moves across at least 25% of said journal portion..Iaddend..Iadd.35. A valveless, positive displacement pump according to claim 28 wherein said scraping edge forms a scraping angle of at least 45.degree...Iaddend..Iadd.36. A valveless, positive displacement pump for pumping a fluid from a fluid source to a fluid outlet comprising:

a substantially hollow sleeve, said sleeve comprising a pumping portion and a journal portion, said pumping portion comprising at least one inlet and at least one outlet;
a piston comprising a pumping portion and a journal portion, wherein said piston is movably supported at least partially within said sleeve such that said journal portion of said sleeve overlaps said journal portion of said piston forming a contact area, and wherein said pumping portion of said piston displaces a fluid within said pumping portion of said sleeve, said journal portion of said piston comprising a generally cylindrical cross-section with an outer diameter dimensioned to provide a clearance of less than 0.0005 inches between said journal portion of said piston and said journal portion of said sleeve;
at least one of said piston or said sleeve further comprising a scraping edge with a scraping angle of at least 45.degree. which moves across a portion of said contact area to scrape said coagulum from said gap..Iaddend..Iadd.37. A valveless, positive displacement pump according to claim 36 wherein said scraping angle is at least 60.degree...Iaddend..Iadd.38. A valveless, positive displacement pump according to claim 36 wherein said scraping angle is at least 90.degree...Iaddend..Iadd.39. A valveless, positive displacement pump according to claim 36 wherein said scraping angle is greater than 90.degree...Iaddend.
Referenced Cited
U.S. Patent Documents
2791209 May 1957 Sheppard
3880055 April 1975 Nakamura et al.
3923428 December 1975 Clark et al.
4772184 September 20, 1988 Laing et al.
4846051 July 11, 1989 Wade et al.
4955284 September 11, 1990 Faulkner
5020980 June 4, 1991 Pinkerton
5158441 October 27, 1992 Aid et al.
Patent History
Patent number: RE35997
Type: Grant
Filed: Jan 17, 1996
Date of Patent: Dec 22, 1998
Assignee: Roper Holdings, Inc. (Wilmington, DE)
Inventor: Dennis T. Pinkerton (West Islip, NY)
Primary Examiner: Thomas E. Denion
Law Firm: Galgano & Burke
Application Number: 8/587,997
Classifications
Current U.S. Class: 92/1701; Nonmetallic Portion (92/248)
International Classification: F01B 1102; F16J 1000;