Ball and seat-type check valve for downhole rod pump

• US 5,297,579 A
• Filed: 04/14/1992
• Issued: 03/29/1994
• Est. Priority Date: 05/23/1990
• Status: Expired due to Fees

• Current Assignee: Douglas A. Jensen, Kenneth R. Mcconnell
• Original Assignee: Douglas A. Jensen, Kenneth R. Mcconnell
• Inventors: McConnell, Kenneth R., Jensen, Douglas A.
• Primary Examiner(s): Nilson, Robert G.
• Application Number:
  US07/868,361
• Time in Patent Office: 714 Days
• Field of Search: 137/515.5, 137/515.7, 137/533.25, 137/533.29, 137/543
• US Class Current: 137/515.7
• CPC Class Codes: F16K 15/04 shaped as balls
• CPC Class Codes: F16K 15/06 with guided stems
• CPC Class Codes: Y10T 137/7857 Valve seat clamped between coupling elements
• CPC Class Codes: Y10T 137/7917 Oppositely disposed
• CPC Class Codes: Y10T 137/7919 Guide and seat integral unit
• CPC Class Codes: Y10T 137/7933 Yoke or cage-type support for valve stem

Abstract

The plunger of the valve has a semi-spherical valve member of reduced diameter, so that it is inwardly spaced from the ribs of the cage. The plunger is centralized and guided by top and bottom stems attached to the ball and working loosely in apertured webs carried by the cage and seat member. The cage has 2 or 3 ribs only, so that the windows are wider. The cage web is downwardly spaced from the top of the cage, to maximize the area of the cage outlet. The valve member has a reduced diameter neck at its upper end, to keep the valve member downwardly spaced from the cage web when the valve is fully open. As a result of these features the cross-sectional areas of the flow passage through the opened valve are increased. The stems are preferably straight-sided and the web openings are circular so fluid may flush out solids packing between the stems and webs. The valve has been improved to increase flow capacity and ensure line contact seating which can be maintained even though there is wear of the parts.

Claims

1. A check valve for assembly and use in a downhole rod pump, comprising:

a tubular one-piece barrel having a longitudinal bore;

a tubular nose sub adapted to thread into the lower end of the barrel and having a longitudinal bore;

a hollow cylindrical cage adapted to be contained in the upper end of the barrel bore, said cage having upstanding, spaced apart ribs forming its side wall and defining flow windows therebetween, said cage forming an internal chamber having a bottom inlet and top outlet;

a tubular seat member, forming a longitudinal bore, adapted to be retained in the lower end of the barrel bore by end support from the nose sub, said seat member forming an annular valve seat;

means for retaining the cage in the barrel bore;

a plunger having a valve member adapted to be disposed in the cage chamber, said valve member having upper and lower ends, said lower end forming an arcuate sealing surface adapted to seal against the valve seat with essentially line contact to effect a liquid-tight seal, the valve member being spaced inwardly from the ribs;

the seat member and nose sub being adapted to form a unit for cooperating with the barrel to effect a liquid-tight lower outer seal for preventing downward leakage of liquid through the check valve when the valve member is seated;

the length of the cage chamber being sufficient to allow the valve member to be displaced upwardly off the valve seat to open a flow passage extending through the assembled check valve;

the plunger having centrally located upper and lower guide stems extending axially from the upper and lower ends of the valve member;

the seat member and cage each having a transversely extending guide web forming a central aperture for receiving and loosely guiding the guide stems to centralize the valve member, each associated guide means and stem having a clearance therebetween for enabling sand particles to pass therethrough.

2. The check valve according to claim 1 wherein:

the upper guide web of the cage is spaced downwardly from the top ends of the ribs to open up the top outlet of the cage; and

the number of ribs is two or three.

3. The check valve according to claim 2 wherein:

the valve member is generally semi-spherical; and

the cage guide web comprises legs extending inwardly from each of the ribs and connector means connecting the ends of the legs and forming the central aperture.

4. The check valve according to claim 3 wherein:

the valve member has spacer means at its upper end for spacing it downwardly from the upper guide web when the valve is fully open.

5. The check valve according to claim 4 wherein:

one of each guide stem and associated web aperture is partially straight-sided and the other is circular.

6. The check valve as set forth in claim 4 wherein:

the cage retaining means is a tubular member adapted to threadably connect with the upper end of the barrel.

7. The check valve as set forth in claim 2 comprising:

a seal ring for retention between the cage retaining means and the cage for preventing leakage through the threaded connection of said means with the barrel.

8. The check valve as set forth in claim 3 comprising:

a seal ring for retention between the cage retaining means and the cage for preventing leakage through the threaded connection of said means with the barrel.

9. The check valve as set forth in claim 4 comprising:

a seal ring for retention between the cage retaining means and the cage for preventing leakage through the threaded connection of said means with the barrel.

10. The check valve as set forth in claim 5 comprising:

a seal ring for retention between the cage retaining means and the cage for preventing leakage through the threaded connection of said means with the barrel.

11. The check valve as set forth in claim 2 comprising:

the cage having top and bottom ring connectors connecting the ribs; and

tubular first means, adapted to connect with the upper end of the barrel, for retaining the cage in the barrel.

12. The check valve as set forth in claim 3 comprising:

the cage having top and bottom ring connectors connecting the ribs; and

tubular first means, adapted to connect with the upper end of the barrel, for retaining the cage in the barrel.

13. The check valve as set forth in claim 4 comprising:

the cage having top and bottom ring connectors connecting the ribs; and

tubular first means, adapted to connect with the upper end of the barrel, for retaining the cage in the barrel.

14. The check valve as set forth in claim 7 comprising:

the cage having top and bottom ring connectors connecting the ribs; and

tubular first means, adapted to connect with the upper end of the barrel, for retaining the cage in the barrel.

15. The check valve as set forth in claim 8 comprising:

the cage having top and bottom ring connectors connecting the ribs; and

tubular first means, adapted to connect with the upper end of the barrel, for retaining the cage in the barrel.

16. The check valve as set forth in claim 9 comprising:

the cage having top and bottom ring connectors connecting the ribs; and

tubular first means, adapted to connect with the upper end of the barrel, for retaining the cage in the barrel.

17. The check valve as set forth in claim 10 comprising:

the cage having top and bottom ring connectors connecting the ribs; and

tubular first means, adapted to connect with the upper end of the barrel, for retaining the cage in the barrel.

18. A check valve replacement assembly for use in a check valve of the type used in a downhole rod pump, comprising:

a hollow open-ended cylindrical cage forming an internal chamber and comprising transverse upper and lower ring connectors at each end joined by substantially equally spaced apart, upstanding ribs forming the cage side wall and defining flow windows therebetween said cage having a transversely extending web forming a central aperture, said web projecting across the cage chamber, said web being spaced downwardly from the upper ring connector, said web being formed by inwardly projecting legs joined at their inner ends by aperture-forming means, whereby an upper outlet from the cage is formed between the web and upper ring connector;

a tubular seat member forming a longitudinal bore and having its side wall recessed at its upper end to form a thinned side wall end portion, said portion forming an annular valve seat, said seat member having a transversely extending web forming a central aperture, said web projecting across its bore adjacent its lower end;

a plunger having a valve member adapted to be disposed in the cage chamber, said valve member having upper and lower ends, said lower end forming an arcuate sealing surface adapted to seal against the valve seat with essentially line contact to effect a liquid-tight seal, the valve member being inwardly spaced from the ribs when operating in the cage;

the plunger having centrally located upper and lower guide stems extending axially from the upper and lower ends of the valve member;

said cage and seat member web apertures being adapted to slidably receive the upper and lower guide stems respectively, when assembled, each associated web and stem having a clearance therebetween.

19. The assembly according to claim 18 wherein:

the valve member is generally semi-spherical.

20. The assembly according to claim 19 wherein:

the valve member has spacer means at its upper end for spacing it downwardly from the upper guide web when the assembly is fully open.

21. The assembly according to claim 19 wherein:

the number of ribs is two or three.

22. The assembly according to claim 20 wherein:

the number of ribs is two or three.

23. A check valve for use in a downhole rod pump, comprising:

an upper tubular one-piece barrel having a longitudinal bore and forming an inwardly projecting reduced diameter ring between its ends;

a tubular seat member forming a longitudinal bore and having its side wall recessed at its upper end to form a radial shoulder and a thinned side wall end portion, said shoulder abutting the lower shoulder of the barrel inner ring, said end portion forming an annular valve seat, said seat member having a transversely extending web, forming a central aperture, projecting across its bore adjacent its lower end;

a tubular nose sub threaded into the lower end of the barrel for retaining the seat member in the barrel against the barrel inner ring;

a hollow open-ended cylindrical cage forming an internal chamber and seated on the upper shoulder of the barrel inner ring, said cage comprising transversely extending upper and lower ring connectors at each end joined by substantially equally spaced apart, upstanding ribs forming the cage side wall and defining flow windows therebetween, said cage having a transversely extending web, forming a central aperture, projecting across the cage chamber, said web being spaced downwardly from the upper ring connector, said web being formed by inwardly projecting legs joined at their inner ends by aperture-forming means, whereby the lower connector forms a lower cage inlet and an upper cage outlet is formed between the cage web and upper ring connector;

a tubular top sub threaded into the upper end of the barrel for retaining the cage in the barrel against the barrel inner ring;

a plunger having a valve member disposed in the cage chamber, said valve member having upper and lower ends, said lower end forming an arcuate seating surface adapted to seal against the valve seat with essentially line contact to effect a liquid-tight seal, the valve member being inwardly spaced from the ribs;

the plunger having centrally located upper and lower guide stems extending axially from the upper and lower ends of the valve member and being slidably received in the web aperture of the cage and valve member;

each stem and associated web aperture having a loose fit and a clearance therebetween;

the entire outer side surfaces of the cage and seat member being in contiguous supporting contact with the barrel;

the length of the cage chamber being sufficient to allow the valve member to be displaced upwardly off the valve seat to open a flow passage extending through the check valve;

the seat member and nose sub forming a unit for cooperating with the barrel to effect a liquid-tight lower outer seal for preventing downward leakage of liquid through the check valve when the valve member is seated.

24. The check valve according to claim 23 wherein:

the number of cage ribs is two or three;

the valve member is generally semi-spherical; and

a seal ring is positioned between the top sub and cage to seal the thread connection between barrel and top sub.

25. The check valve according to claim 24 wherein:

one of each guide stem and associated web aperture is partially straight-sided and the other is circular.

26. The check valve according to claim 24 wherein:

the valve member has spacer means at its upper end for spacing it downwardly from the upper guide web when the valve is fully open.