Hydraulic actuator with built-in pressure compensator

• US 6,783,107 B2
• Filed: 07/12/2002
• Issued: 08/31/2004
• Est. Priority Date: 02/14/2002
• Status: Active Grant

• Current Assignee: HP&T Products Incorporated (National Oilwell Varco Incorporated)
• Original Assignee: HP&T Products Incorporated (National Oilwell Varco Incorporated)
• Inventors: Chatufale, Vijay
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): Fristoe, Jr., John K.
• Application Number:
  US10/194,871
• Publication Number:
  US 20020175303A1
• Time in Patent Office: 781 Days
• Field of Search: 251/54, 251/63.5, 251/63.6, 91/4.R
• US Class Current: 251/54
• CPC Class Codes: F15B 1/24 with rigid separating means, e.g. pistons
• CPC Class Codes: F15B 15/1433 End caps F15B15/1438 takes precedence
• CPC Class Codes: F15B 21/006 Compensation or avoidance of ambient pressure variation
• CPC Class Codes: F15B 2201/21 using springs
• CPC Class Codes: F15B 2201/312 Sealings therefor, e.g. piston rings
• CPC Class Codes: F15B 2201/32 having multiple separating means, e.g. with an auxiliary piston sliding within a main piston, multiple membranes or combinations thereof
• CPC Class Codes: F15B 2201/411 having valve means

Abstract

A hydraulic actuator (20) with a built-in hydrostatic pressure compensator (111) is provided. The actuator (20) includes an actuator housing (30), a compensator cylinder portion (86), a compensator piston portion (94), a first compensator piston chamber (98), a second compensator piston chamber (103), a hydraulic port (106), and a hydraulic via (108). The compensator cylinder portion (86) is located within the actuator housing (30), is fixed relative to the housing (30), and has a compensator cylinder internal chamber (88) formed therein. The compensator piston portion (94) slidably fits within the compensator cylinder internal chamber (88). The first compensator piston chamber (98) is formed between a first side (101) of the compensator piston portion (94) and the compensator cylinder portion (86). The second compensator piston chamber (103) is formed between a second side (102) of the compensator piston portion (94) and the compensator cylinder portion (86). The hydraulic port (106) is routed through the housing (30) and opens to the first compensator piston chamber (98). The hydraulic via (108) fluidly couples the second compensator piston chamber (103) with a first housing internal chamber (82).

Claims

1. A hydraulic actuator, comprising:

an actuator housing;

a built-in pressure compensator located within the housing, the built-in pressure compensator comprising;

a compensator cylinder portion located within the actuator housing, the compensator cylinder portion being fixed relative to the housing, and the compensator cylinder portion having an internal chamber formed therein,

a compensator piston portion slidably fitting within the compensator internal chamber, a first compensator piston chamber being formed between a first side of the compensator piston portion and the compensator cylinder portion within the compensator internal chamber, a second compensator piston chamber being formed between a second side of the compensator piston portion and the compensator cylinder portion within the compensator internal chamber, wherein a compensator hydraulic port is routed through the housing, one end of the hydraulic port opening outside of the housing and another end of the hydraulic port opening to the first compensator piston chamber;

a first housing internal chamber formed within the housing;

a first hydraulic passageway formed through the compensator cylinder portion and fluidly coupling the second compensator piston chamber with the first housing internal chamber;

an operating stem extending into the housing and slidably coupled to the housing, the operating stem being coupleable to a valve;

an actuator cylinder portion slidably fitting within the housing, the actuator cylinder portion having an actuator cylinder internal chamber formed therein with a closed end and an open end, and the actuator cylinder portion being mechanically coupled to the operating stem, wherein the first housing internal chamber is formed between the housing and the actuator cylinder portion at the open end of the actuator cylinder internal chamber, such that the actuator cylinder internal chamber of the actuator cylinder portion opens to the first housing internal chamber;

a spring located within the housing, the spring being biased between the housing and the actuator cylinder portion; and

an actuator piston portion located within the housing, being fixed relative to the housing, extending through the open end of the actuator cylinder internal chamber, and slidably fitting into the actuator cylinder internal chamber of the actuator cylinder portion.

2. The actuator according to claim 1, further comprising a stop ring located between the actuator cylinder portion and the housing, the stop ring being positioned so as to limit the displacement of the actuator cylinder portion in one direction.

3. The actuator according to claim 1, wherein the spring is submerged in hydraulic fluid and the volume of hydraulic fluid that the spring is submerged in remains constant and remains sealed within the housing during use of the actuator.

4. The actuator according to claim 1, wherein the spring is strong enough to move the actuator cylinder portion to one of its displacement limits so that the actuator is a failsafe actuator.

5. The actuator according to claim 1, further comprising:

a second housing internal chamber formed within the housing between the housing and an exterior of the actuator cylinder portion;

an actuator piston chamber formed between the actuator piston portion and the actuator cylinder portion within the actuator cylinder internal chamber;

an actuator hydraulic port routing through the actuator piston portion and the housing, one end of the actuator hydraulic port opening outside of the housing and another end of the actuator hydraulic port opening to the actuator piston chamber; and

a second hydraulic passageway formed through the actuator cylinder portion and fluidly coupling the first housing internal chamber with the second housing internal chamber.

6. The actuator according to claim 5, further comprising a spring plate ring located about the exterior of the actuator cylinder portion between the spring and the actuator cylinder portion.

7. The actuator according to claim 6, wherein the spring plate ring and the actuator cylinder portion comprise separate pieces, wherein the actuator cylinder portion includes a flange portion extending from the exterior thereof, and wherein the spring plate ring presses against the flange portion of the actuator cylinder portion.

8. The actuator according to claim 6, wherein the spring plate ring is integral to the actuator cylinder portion.

9. The actuator according to claim 5, wherein the spring is located in the second housing internal chamber.

10. The actuator according to claim 5, wherein the housing comprises:

a bonnet portion; and

an outer sidewall portion removably attached to the bonnet portion, wherein the actuator piston portion is removably attached to the outer sidewall portion.

11. The actuator according to claim 10, wherein the housing further comprises:

a first seal between the outer sidewall portion and the bonnet portion;

a second seal between the actuator piston portion and the outer sidewall portion;

a packing gland about the operating stem and secured within the bonnet portion;

a first seal ring between the operating stem and the packing gland; and

a second seal ring between the packing gland and the bonnet portion.

12. The actuator according to claim 10, further comprising a retainer ring located about the outer sidewall portion and fastened to the bonnet portion, wherein the outer sidewall portion is attached to the bonnet portion using the retainer ring.

13. The actuator according to claim 12, wherein the retainer ring and the outer sidewall portion comprise separate pieces.

14. The actuator according to claim 12, wherein the retainer ring is integral to the outer sidewall portion.

15. The actuator according to claim 10, further comprising:

a first filling port routed within the housing, one end of the first filling port opening outside of the housing and another end of the first filling port opening to the first housing internal chamber; and

a second filling port routed within the bonnet portion, one end of the second filling port opening outside of the bonnet portion and another end of the second filling port opening to the second housing internal chamber.

16. The actuator according to claim 1, wherein the housing further comprises:

a cover plate removably attached to the compensator cylinder portion to form an enclosure for the compensator cylinder internal chamber, wherein the compensator hydraulic port is formed through the cover plate; and

a third seal between the cover plate and the compensator cylinder portion.

17. The actuator according to claim 1, wherein the housing is filled with hydraulic fluid.

18. A method of producing petroleum, comprising:

coupling the actuator according to claim 1 to a valve; and

controlling the flow of petroleum through the valve using the actuator during production operations.

19. A method of compensating for pressure changes and hydraulic fluid displacement within an actuator, comprising:

providing an actuator according to claim 1;

inputting hydraulic fluid into the actuator; and

compensating for pressure changes and hydraulic fluid displacement within the actuator using the built-in pressure compensator.

20. The actuator according to claim 1, wherein the compensator piston portion is unrestrained from sliding relative to the compensator cylinder portion within the compensator cylinder internal chamber.

21. The actuator according to claim 1, further comprising a relief valve coupled to the compensator piston portion, wherein the relief valve is fluidly coupled to the second compensator piston chamber.

22. The actuator according to claim 1, further comprising a first filling port routed within the housing, one end of the first filling port opening outside of the housing and another end of the first filling port opening to the first housing internal chamber.

23. A hydraulic actuator, comprising:

an actuator housing;

a built-in pressure compensator located within the housing, the built-in pressure compensator comprising;

a compensator cylinder portion located within the actuator housing, the compensator cylinder portion being fixed relative to the housing, and the compensator cylinder portion having an internal chamber formed therein,

a compensator piston portion slidably fitting within the compensator internal chamber, a first compensator piston chamber being formed between a first side of the compensator piston portion and the compensator cylinder portion within the compensator internal chamber, a second compensator piston chamber being formed between a second side of the compensator piston portion and the compensator cylinder portion within the compensator internal chamber, wherein a compensator hydraulic port is routed through the housing, one end of the hydraulic port opening outside of the housing and another end of the hydraulic port opening to the first compensator piston chamber;

a first housing internal chamber formed within the housing; and

a first hydraulic passageway formed through the compensator cylinder portion and fluidly coupling the second compensator piston chamber with the first housing internal chamber, wherein the compensator piston portion is unrestrained from sliding relative to the compensator cylinder portion within the compensator cylinder internal chamber.

24. A method of producing petroleum, comprising:

coupling the actuator according to claim 23 to a valve; and

controlling the flow of petroleum through the valve using the actuator during production operations.

25. A method of compensating for pressure changes and hydraulic fluid displacement within an actuator, comprising:

providing an actuator according to claim 23;

inputting hydraulic fluid into the actuator; and

compensating for pressure changes and hydraulic fluid displacement within the actuator using the built-in pressure compensator.

26. A hydraulic actuator, comprising:

an actuator housing;

a built-in pressure compensator located within the housing, the built-in pressure compensator comprising;

a compensator cylinder portion located within the actuator housing, the compensator cylinder Portion being fixed relative to the housing, and the compensator cylinder portion having an internal chamber formed therein,

a compensator piston portion slidably fitting within the compensator internal chamber, a first compensator piston chamber being formed between a first side of the compensator piston portion and the compensator cylinder portion within the compensator internal chamber, a second compensator piston chamber being formed between a second side of the compensator piston portion and the compensator cylinder portion within the compensator internal chamber, wherein a compensator hydraulic port is routed through the housing, one end of the hydraulic port opening outside of the housing and another end of the hydraulic port opening to the first compensator piston chamber;

a first housing internal chamber formed within the housing;

a first hydraulic passageway formed through the compensator cylinder portion and fluidly coupling the second compensator piston chamber with the first housing internal chamber; and

a relief valve coupled to the compensator piston portion, wherein the relief valve is fluidly coupled to the second compensator piston chamber.

27. A method of producing petroleum, comprising:

coupling the actuator according to claim 26 a valve; and

controlling the flow of petroleum through the valve using the actuator during production operations.

28. A method of compensating for pressure changes and hydraulic fluid displacement within an actuator, comprising:

providing an actuator according to claim 26;

inputting hydraulic fluid into the actuator; and

compensating for pressure changes and hydraulic fluid displacement within the actuator using the built-in pressure compensator.

29. A hydraulic actuator for controlling a valve, comprising:

a housing;

an operating stem extending into the housing and slidably coupled to the housing, the operating stem being coupleable to the valve;

a first cylinder portion slidably fitting within the housing, the first cylinder portion having a first cylinder internal chamber formed therein with a closed end and an open end, and the first cylinder portion being mechanically coupled to the operating stem;

a first housing internal chamber formed within the housing between the housing and the first cylinder portion at the open end of the first cylinder internal chamber, such that the first cylinder internal chamber of the first cylinder portion opens to the first housing internal chamber;

a second housing internal chamber formed within the housing between the housing and an exterior of the first cylinder portion;

a spring located within the housing, the spring being biased between the housing and the first cylinder portion;

a first piston portion located within the housing, being fixed relative to the housing, extending through the open end of the first cylinder internal chamber, and slidably fitting into the first cylinder internal chamber of the first cylinder portion;

a first piston chamber formed between the first piston portion and the first cylinder portion within the first cylinder internal chamber;

a second cylinder portion located within the housing, the second cylinder portion being fixed relative to the housing, and the second cylinder portion having a second cylinder internal chamber formed therein;

a second piston portion located within the housing and slidably fitting within the second cylinder internal chamber;

a second piston chamber formed between a first side of the second piston portion and the second cylinder portion within the second cylinder internal chamber;

a third piston chamber formed between a second side of the second piston portion and the second cylinder portion within the second cylinder internal chamber;

a first hydraulic port routing through the first piston portion and the housing, one end of the first hydraulic port opening outside of the housing and another end of the first hydraulic port opening to the first piston chamber;

a second hydraulic port routing through the housing, one end of the second hydraulic port opening outside of the housing and another end of the second hydraulic port opening to the second piston chamber;

a first hydraulic passageway formed through the second cylinder portion and fluidly coupling the third piston chamber with the first housing internal chamber; and

a second hydraulic passageway formed through the first cylinder portion and fluidly coupling the first housing internal chamber with the second housing internal chamber.

30. The actuator according to claim 29, wherein the housing comprises:

a bonnet portion;

an outer sidewall portion removably attached to the bonnet portion, wherein the first piston portion is removably attached to the outer sidewall portion;

a first seal between the outer sidewall portion and the bonnet portion;

a second seal between the first piston portion and the outer sidewall portion;

a packing gland about the operating stem and secured within the bonnet portion;

a first seal ring between the operating stem and the packing gland;

a second seal ring between the packing gland and the bonnet portion;

a cover plate removably attached to the second cylinder portion to form an enclosure for the second cylinder internal chamber, wherein the second hydraulic port is formed through the cover plate; and

a third seal between the cover plate and the second cylinder portion.

31. The actuator according to claim 29, wherein the spring is submerged in hydraulic fluid and the volume of hydraulic fluid that the spring is submerged in remains constant and remains sealed within the housing during use of the actuator.

32. The actuator according to claim 29, wherein the spring is located in the second housing internal chamber.

33. The actuator according to claim 29, further comprising a relief valve coupled to the second piston portion, wherein the relief valve is fluidly coupled to the third piston chamber.

34. A method of manufacturing an actuator, comprising:

providing an actuator housing;

disposing a compensator cylinder portion within the actuator housing, the compensator cylinder portion being fixed relative to the housing and having a compensator internal chamber formed therein;

slidably fitting a compensator piston portion within the compensator internal chamber, wherein a first compensator piston chamber is formed between a first side of the compensator piston portion and the compensator cylinder portion, wherein a second compensator piston chamber is formed between a second side of the compensator piston portion and the compensator cylinder portion;

forming a hydraulic port through the housing such that the hydraulic port opens to the first compensator piston chamber;

forming a hydraulic passageway through the compensator cylinder portion to fluidly couple the second compensator piston chamber with a first housing internal chamber, wherein at least the compensator cylinder portion and compensator piston portion comprise a built-in pressure compensator;

extending an operating stem into the housing, the operating stem being slidably coupled to the housing, the operating stem being coupleable to a valve;

slidably fitting an actuator cylinder portion within the housing, the actuator cylinder portion having an actuator cylinder internal chamber formed therein with a closed end and an open end, and the actuator cylinder portion being mechanically coupled to the operating stem, wherein the first housing internal chamber is formed between the housing and the actuator cylinder portion at the open end of the actuator cylinder internal chamber, such that the actuator cylinder internal chamber of the actuator cylinder portion opens to the first housing internal chamber;

biasing a spring within the housing between the housing and the actuator cylinder portion; and

disposing an actuator piston portion within the housing, the actuator piston portion being fixed relative to the housing, extending through the open end of the actuator cylinder internal chamber, and slidably fitting into the actuator cylinder internal chamber of the actuator cylinder portion.

35. The method according to claim 34, further comprising forming at least one filling port in the actuator housing, and filling the actuator with hydraulic fluid through the at least one filling port.

36. The method according to claim 35, further comprising bleeding the actuator through one said at least one filling port.

37. The method according to claim 34, wherein providing the actuator housing comprises providing a bonnet portion proximate the spring and operating stem, further comprising:

forming a first filling port within the housing, one end of the first filling port opening outside of the housing and another end of the first filling port opening to the first housing internal chamber;

forming a second filling port in the bonnet portion, one end of the second filling port opening outside of the bonnet portion and another end of the second filling port opening to a second housing internal chamber formed within the actuator housing between the actuator housing and an exterior of the actuator cylinder portion; and

filling the actuator with hydraulic fluid through the first filling port or the second filling port.

38. The method according to claim 37, further comprising bleeding the actuator through the first filling port or the second filling port.

39. The method according to claim 37, further comprising plugging the first filling port and the second filling port.