WO2016012739A1

WO2016012739A1 - Sub-plate mounted valve

Info

Publication number: WO2016012739A1
Application number: PCT/GB2014/052293
Authority: WO
Inventors: Jonathan Lynch; Paul Campbell
Original assignee: Axon Energy Products Uk Ltd
Priority date: 2014-07-25
Filing date: 2014-07-25
Publication date: 2016-01-28

Abstract

A sub-plate mounted valve (100) for installation in a sub-plate or manifold as used in subsea hydrocarbon recovery systems. The sub- plate mounted valve (100) includes a valve spool (124) moveable within a valve body (114) between two positions corresponding to two valve seats. At least one of the valve seats creates a cylindrical seal around a portion of the outside surface of the valve spool (124), enabling the valve spool (124) to be integrally formed with a valve stem (122) and other valve components. The valve body (114) includes a cage (portion 116) having holes (118B/120B) for permitting flow through the vale (100).

Description

SUB-PLATE MOUNTED VALVE

TECHNICAL FIELD

The present disclosure relates to sub-plate mounted valves generally used to control flow of pressurized fluids in subsea blow out preventers.

BACKGROUND

Subsea hydrocarbon recovery systems normally include a blowout preventer for sealing, controlling, and monitoring well operations. Control and operation of the blowout preventer and related equipment is typically achieved through a system of hydraulic actuators controlled by a manifold having multiple control valves. Among the control valves commonly used in such arrangements are sub-plate mounted valves.

Generally, one or more sub-plate mounted valves are installed directly into the manifold. Each valve is pilot-operable between two positions. In the first position, the valve permits fluid flow from a high-pressure supply port of the manifold to a function port. The function port is in turn connected to a piece of hydraulic equipment to be controlled. In the second position, the valve relieves pressure in the hydraulic circuit by permitting flow through a return loop or venting the fluid.

Subsea operations continue to progress towards deeper and harsher oceanic environments. As a result, there is a growing need for subsea equipment capable of effectively and efficiently operating in such environments. With respect to sub-plate mounted valves specifically, the flow path through the valve directly affects the valve's efficiency. Restrictions and tortuous flow paths cause energy losses to the fluid which are magnified as operating pressure increases. Further, increased operating pressures heighten the demand for effective sealing between valve components. Complex valve designs requiring multiple seals between components may therefore become prone to leakage when subjected to subsea pressures. As a result, there is a need for a sub- plate mounted valve with improved flow efficiency and simplified construction suitable for deep sea applications.

SUMMARY

Embodiments of the present disclosure are directed to a sub-plate mounted valve having simplified construction and improved flow characteristics.

In accordance with the present disclosure, the sub-plate mounted valve includes a body and a valve stem having a piston and a spool. The valve stem is movable between an open and closed position. In the closed position, the spool seals against a cylindrical seal while in the open position, the spool seals against a t-seal seal inserted into the inside surface of the valve body. Because of this sealing arrangement, both the valve body and valve stem may be constructed as single pieces, reducing the number of seals required within the valve and simplifying construction and assembly of the valve.

Certain embodiments of the sub-plate mounted valve include various features for efficient flow through the valve.

In some embodiments, the t-seal and cylindrical seal are configured to minimize interflow through the valve. Specifically, the seals are arranged such that both seals seal against the spool at the midpoint of the valve stroke, ensuring that only one manifold port is open at a time.

Other embodiments include modifications to the valve body to reduce restrictions through the valve. The valve body includes a portion commonly referred to as a cage that includes holes for communicating fluid into the valve. According to certain embodiments overall flow efficiency is improved by making the holes wider than their corresponding manifold ports, slotted in shape, and with rounded edges. In other embodiments, the holes are eccentric from the centers of the ports, allowing flow through the valve at earlier points in the valve stroke. In still other embodiments, the cage has a smaller outside diameter than the inside diameter of the valve pocket, creating a gap that limits restrictions to flow through the valve. Embodiments of valves in accordance with this disclosure also include an alignment mechanism to ensure proper installation of the valve into a manifold. Specifically, during installation, the spring housing and valve body are coupled together using a pin or lock such that the holes in the cage align with indicators on the top of the spring housing. During installation, the valve can be rotated to align the indicators on the top of the spring housing with indicators on the manifold, ensuring proper alignment of the valve.

These and various other features and advantages will be apparent from a reading of the following detailed description and drawings along with the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments and advantages of the present disclosure may be best understood by one of ordinary skill in the art by referring to the following description and accompanying drawings. In the drawings:

FIG. 1 is a cross-sectional view of a sub-plate mounted valve in the open position.

FIG. 2 is a cross-sectional view of a sub-plate mounted valve in the closed position.

FIG. 3 is a cross-sectional view of a sub-plate mounted valve having a normally-closed configuration.

FIGS. 4A-C are partial cross-sectional views of a spool depicting three positions, open, closed, and mid-stroke, respectively.

FIG. 5A is a cross-sectional view of a valve body.

FIG. 5B is a cross-sectional view of a valve body installed in a valve pocket.

FIG. 6A is a top-down view of a valve installed in a manifold illustrating alignment markers on the spring housing.

FIG. 6B is a cross-sectional view of a valve installed in a valve pocket. DETAILED DESCRIPTION

FIG. 1 is a cross-sectional view of a sub-plate mounted valve 100 according to one embodiment of the present disclosure. The valve 100 is depicted as being installed in a manifold 102. Alternatively, the valve 100 may be installed into a sub-plate.

As shown in FIG. 1, the manifold 102 is machined to have a valve pocket 104 to receive the valve 100 and a series of ports for directing fluid through the valve 100. As depicted, the ports include a function port 106, a supply port 108 through which a fluid is provided, a return port 110, and a pair of pilot ports 112A-B. The function port 106 is connected to a pneumatic or hydraulic circuit for performing a particular function when pressurized fluids are supplied to the circuit. As depicted in FIG. 1, the supply port 108 and the return port 110 are located on the same side of the valve pocket 104. In other embodiments, the supply port 108 and the return port 110 may be located on different sides of the valve pocket 104.

According to one embodiment, the valve 100 includes a valve body 114. A portion of the valve body 114 called the cage 116 includes a series of holes. As depicted and visible in FIG. 1, the holes include supply holes 118A-B and return holes 120A-B that correspond to the supply port 108 and the return port 110, respectively. Generally, the number and location of the supply holes 118A- B and the return holes 120A-B may vary depending on the arrangement of the supply port 108 and the return port 110 within the valve pocket 104.

The valve 100 also includes a movable valve stem 122. The valve stem 122 includes a hollow valve spool 124 and a series of pistons 126A-B. The valve stem 122 is selectively operated by supplying pressurized fluid through one of the pilot ports 112A-B into one of two chambers 128A-B defined by the valve body 114 and the valve stem 122 and pistons 126A-B.

Supplying pressurized fluid through pilot port 112B into chamber 128B causes the valve 100 to actuate into an open position as depicted in FIG. 2. In the open position, a flow path is created between the function port 106 and the supply port 108, allowing fluid to travel from the supply port 108 to the function port 106 and into the hydraulic circuit.

Supplying pressure through pilot port 112A into chamber 128A causes the valve 100 to actuate into a closed position, as depicted in FIG. 1. In the closed position, the spool 124 is positioned to create a flow path between the function port 106 and the return port 110. In the closed position, fluid is permitted to flow from the function port 106, through the spool 124 and through the return port 110, reducing pressure in the circuit. The fluid may be returned to a reservoir or, in some embodiments, the return port 110 may instead be a vent port leading to a vent for relieving the fluid to atmosphere.

The embodiment of the valve 100 depicted in FIG. 1 can be biased in a closed position. A spring 130 located within a spring housing 132 applies force to the valve stem 122 through a spring retainer 134 and biases the valve 100 into the closed position. In contrast, FIG. 3 is a cross-sectional view of a sub-plate mounted valve 300 according to another embodiment in which the valve is biased in an open position. In the open configuration, spring 330 biases the valve 300 in the open position. Generally, this is done by extending the valve stem 322 through the spring 330 and connecting the valve stem 322 to a spring retainer 334 located on the opposite end of the spring than in the biased closed configuration.

During installation, the valve stem 122 is inserted into the valve body 114. The valve body 114 is then coupled to the spring housing 132 and inserted into the valve pocket 104. Once inserted into the valve pocket 104, the spring housing 132 can be rotated causing threads 136 located at the base of the spring housing 132 to engage mating threads 138 at the opening of the valve pocket 104, securing the valve body 114 and valve stem 122 within the valve pocket 104.

FIG. 4A and 4B are cross-sectional view of a biased closed valve in the open and closed positions, respectively. The valve includes a variety of seals. In addition to piston seals 450A, 450B around a piston 426 and spool 424, the valve includes a t-seal 402 and a cylinder seal 404. When the valve is in the open position, as depicted in FIG. 4A, the t-seal 402 acts as a valve seat, sealing against the outer surface of the spool. When the valve is in the closed position, the spool seats against the cylinder seal 404. As depicted, the cylinder seal 404 is t-shaped, forming both a cylindrical seal around the outside of the spool 424 and a poppet seal against the leading face of the spool.

The t-seal 402 and cylinder seal 404 are positioned such that interflow is minimized. Interflow is a flow of fluid from the supply port to the return port (instead of the function port) and generally has a negative impact on the flow efficiency of the valve. Interflow occurs when, during the valve stroke, the supply or return port is not completely sealed when the other port is opened. With both the supply port and the return port at least partially open, a flow path is created between them and interflow results.

FIG. 4C depicts the valve at a midpoint in its stroke. As depicted in FIG. 4C, the spool 424 maintains a seal against both the t-seal 402 and cylinder seal 404 at the midpoint of the stroke. As a result, regardless of whether the valve is opening or closing, only one of the return port 410 and the supply port 408 will be opened as the valve continues its stroke.

FIG. 5A is a cross-sectional view of a valve body 514 for a valve according to one embodiment of the present disclosure. The valve body 514 includes a cage 516 that further includes a series of supply holes 518A-C and a series of return holes 520A-C that, when installed, correspond to the supply port and the return port of a manifold, respectively. In certain embodiments, the supply holes 518A-C and return holes 520A-C are arranged to correspond to the locations of supply holes and return holes of a previously installed SPM valve. As a result, the improved SPM valve disclosed herein may be used as a retrofit for existing manifolds.

In one embodiment, the supply 518A-C and return holes 520A-C may be slotted holes. Generally, the slotted supply and return holes have a cross-sectional area that exceeds that of the supply or return port to which they correspond, minimizing restrictions created by the supply or return holes. The slotted holes also permit relatively unrestricted flow when the supply and return holes are not directly aligned with the supply and return ports. To further improve flow efficiency through the slotted holes, the edges of the holes may be rounded as opposed to sharp or edged.

FIG. 5B is a cross-sectional view of valve body 514 as installed in a valve pocket 504. For purposes of explaining features of the valve body 514, a valve stem and other structures are not depicted. The valve pocket 504 includes a supply port 506, a return port 508, and a return port 510.

FIG. 5B includes two structures that can improve flow efficiency through the valve. First, in the region surrounding the supply 518A-C and return holes 520 A-C, the cage 516 has a smaller outside diameter than the inside diameter of the valve pocket 504. The resultant gap between the cage 516 and valve pocket 504 can reduce restrictions as the fluid flows from the ports through the cage 516. The effects of this gap can be stronger when the supply 518A-C and return holes 520A-C are not directly aligned with the supply port 506 and the return port 508.

Second, the supply 518A-C and return holes 520A-C are also depicted as being eccentric with respect to the supply port 508 and the return port 510. Specifically, the supply holes 518A-C are biased towards the function port 506 and the return holes 520A-C are biased away from the function port. Biasing the holes in this manner can improve the transition time between the open and closed positions of the valve. Specifically, fluid can be permitted to flow along the flow path corresponding to the open or closed position at an earlier time in the valve stroke as compared to a design in which the holes and ports are concentric.

To assist in aligning the supply and return holes with the supply and return ports during installation, the valve may include various indicators. FIG. 6A is a top-down view depicting an embodiment of a valve installed in a valve pocket. As depicted in FIG. 6A, the top surface of the valve spring housing 632 includes a set of indicators. In one embodiment, these indicators include one of more major indicators 636 corresponding to the center of the supply and return holes of the valve body. For each major indicator, the spring cover 632 may include minor indicators 638A-B to indicate the extents of the supply and return holes.

FIG. 6B is a cross-sectional view of a valve body 614, valve stem 622, and the spring housing 632 installed in a valve pocket 604. As depicted in FIG. 6B, the valve body may include one or more recesses 640. The spring housing 632 similarly may include one or more holes 642. During installation, the spring housing 632 is placed on the valve body 614 and aligned such that the recesses and holes are aligned and can receive a pin or lock. The pin or lock maintains proper alignment of the spring housing and valve body during insertion into the valve pocket. Once inserted, the valve may be rotated to engage the threads and align one of the major indicators on the spring housing with a marking on the manifold indicating the location of ports within the manifold.

The improved sub-plate mounted valves described in this disclosure is suitable for use in both new equipment and as a retrofit to existing manifold assemblies. To facilitate the use of the improved sub-plate mounted valve as a retrofit component, the improved sub-plate mounted valve may be designed in accordance with industry standard specifications related to overall valve dimensions, material selection, manifold port locations, or other aspects of the valve or equipment. Alternatively, a retrofit may be achieved by designing aspects of the valve to correspond with a previously installed sub-plate mounted valve.

Although numerous characteristics and advantages of embodiments of the present disclosure have been set forth in the foregoing description and accompanying figures, this description is illustrative only. Changes to details regarding structure and arrangement that are not specifically included in this description may nevertheless be within the full extent indicated by the claims.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A sub-plate mounted valve for use in a valve pocket having at least a first port, a second port and a function port, the sub-plate mounted valve comprising

a valve body, the valve body further comprising

a first valve seat;

a second valve seat disposed on an inner surface of the valve body; a cage, the cage defining a first hole corresponding to the first port and a second hole corresponding to the second port; and

a valve spool at least partially disposed within the valve body,

wherein the valve spool is movable along a longitudinal axis of the valve body between

a first position wherein at least a portion of the valve spool seals against the first valve seat and flow is permitted between the first port and the function port via the first hole, and

a second position wherein at least a portion of the outer surface of the valve spool seals against the second valve seat and flow is permitted between the second port and the function port via the second hole.

2. The sub-plate mounted valve of claim 1 wherein

at least a portion of the valve spool maintains a seal against at least one of the first valve seat and the second valve seat as the valve spool is moved between the first position and the second position.

3. The sub-plate mounted valve of claim 1 wherein

the valve spool is selectively moveable between the first and the second position by a pilot- operated piston.

4. The sub-plate mounted valve of claim 3 wherein

the valve spool and the pilot-operated piston are integrally formed with a valve stem.

5. The sub-plate mounted valve of claim 1 further comprising

a spring for biasing the valve spool towards one of the first position and the second position.

6. The sub-plate mounted valve of claim 1 wherein

at least one of the first hole and the second hole are slotted holes.

7. The sub-plate mounted valve of claim 1 wherein

at least one of the first hole is eccentric with the first port and the second hole is eccentric with the second port.

8. The sub-plate mounted valve of claim 1 wherein

at least a portion of the cage does not abut the valve pocket.

9. The sub-plate mounted valve of claim 1 further comprising

a housing coupled to the valve body, the housing comprising a threaded portion corresponding to a threaded portion of the valve pocket, wherein

the sub-plate mounted valve is installed in the valve pocket by mating the threaded portion of the housing with the threaded portion of the valve pocket.

10. The sub-plate mounted valve of claim 9, wherein

the housing further comprises at least one indicator such that when the housing is coupled to the valve body, the indicator aligns with at least one of the first and the second hole.

11. The sub-plate mounted valve of claim 10, wherein

the housing further comprises a plurality of minor indicators, the plurality of minor indicators corresponding to extents of the at least one of the first and the second hole.

12. The sub-plate mounted valve of claim 1, wherein

the sub-plate mounted valve is suitable for replacing a second sub-plate mounted valve previously installed in the valve pocket.

13. The sub-plate mounted valve of claim 1, wherein

the valve spool is integrally formed with a valve stem.

14. The sub-plate mounted valve of claim 13, wherein

the valve stem further includes at least one integrally formed piston for moving the valve stem between the first position and the second position.

15. A manifold assembly, comprising

a valve pocket, the valve pocket comprising

a first port;

a second port; and

a function port; and

a sub-plate mounted valve installed in the valve pocket, the sub-plate mounted valve comprising

a valve body, the valve body further comprising

a first valve seat;

a second valve seat disposed on an inner surface of the valve body;

a cage, the cage defining a first hole corresponding to the first port and a second hole corresponding to the second port; and

a valve spool at least partially disposed within the valve body,

a second position wherein at least a portion of the outer surface of the valve spool seals against the second valve seat and flow is permitted between the second port and the function port via the second hole

16. The manifold of claim 15, wherein

the manifold further comprises a port indicator corresponding to at least one of the first port and the second port; and

the sub-plate mounted valve further comprises at least one hole indicator corresponding to at least one of the first hole and the second hole, wherein

alignment of the port indicator and the hole indicator aligns the first port or the second port with the first hole or the second hole.

17. The manifold of claim 15, wherein

the sub-plate mounted valve is a retrofit for a previously installed sub-plate mounted valve.

18. A method of installing a sub-plate mounted valve in a manifold, comprising:

connecting a cap portion of the sub-plate mounted valve to a body portion of the sub-plate mounted valve such that a cap portion indicator aligns with a hole through the valve body; inserting the sub-plate mounted valve into the manifold, and

rotating the sub-plate mounted valve within the manifold such that the cap portion indicator aligns with at least one manifold port.

19. The method of claim 18, wherein:

aligning the cap portion indicator with the at least one manifold port further comprises aligning the cap portion indicator with a manifold port indicator corresponding to the at least one manifold port.

20. The method of claim 18, further comprising:

removing a previously installed sub-plate mounted valve from the manifold before inserting the sub- plate mounted valve.