Abstract:
The present invention is directed to a valve for controlling the flow of fluid through a component which includes a flow conduit extending therethrough. The valve comprises a first closure member for controlling the flow of fluid through the conduit, a second closure member for controlling the flow of fluid through the conduit, and a valve stem which is connected to both the first and second closure members. The stem is responsive to an external force to move the first and second closure members from a closed position, in which the fluid is blocked from flowing through the conduit by both the first and second closure members, to an open position, in which the fluid is permitted to flow through the conduit past both the first and second closure members.

Description:
This application is based on U.S. Provisional Patent Application No. 60/199,795, which was filed on Apr. 26, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a closure device for controlling the flow of fluid through a conduit. More particularly, the invention relates to a valve which comprises both a poppet type closure member and a gate closure member which are actuated simultaneously to open and close the valve. 
     In flow completion systems for oil and gas wells, closure devices are often employed to isolate the conduits within various flow completion system components from the external environment. For example, a poppet type valve such as the male or female member of a conventional hydraulic coupling may be used to isolate a service and control conduit within a tubing hanger when the coupler is not engaged by a corresponding coupler on the tubing hanger running tool or the tubing spool. However, this type of closure device is prone to leakage and is therefore unreliable as a primary closure device. 
     One solution to this problem is to provide a second, more reliable closure device in the conduit. However, because of the space and weight limitations inherent in many flow completion system components, the use of two closure devices in a single conduit is often not possible. In addition, the second closure device typically must be actuated independently of the first closure device. This usually requires that the flow completion system component be provided with suitable conduits to communicate an actuating fluid to the second closure device, and this necessarily complicates the design of the flow completion system component. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, these and other disadvantages in the prior art are overcome by providing a valve for controlling the flow of fluid through a component which includes a flow conduit extending therethrough, the valve comprising a first closure member for controlling the flow of fluid through the conduit, a second closure member for controlling the flow of fluid through the conduit, a valve stem which is connected to both the first and second closure members, and a spring for biasing the first and second closure members into a first position. The stem is responsive to an external force to move the first and second closure members from the first position to a second position. Moreover, one of the first and second positions corresponds to an open position of the valve, in which the fluid is permitted to flow through the conduit past both the first and second closure members, and the other position corresponds to a closed position of the valve, in which the fluid is blocked from flowing through the conduit by both the first and second closure members. 
     In one embodiment of the invention, the first closure member comprises a poppet head which is adapted to engage a corresponding poppet seat surrounding an opening that is in fluid communication with the conduit. In addition, the second closure member comprises a gate which is slidably positioned between a pair of seats which each comprise a through bore that is in fluid communication with the conduit. The valve preferably also comprises a valve bonnet which includes a male coupling portion that is adapted to connect with a female coupling member of a hydraulic coupler, and the valve stem comprises an actuating tip that is adapted to be engaged by a corresponding portion of the female coupling member to move the valve stem and thus the first and second closure members from the first position to the second position. In this manner, when the female coupling member is connected to the valve, the valve stem will actuate both the poppet closure member and the gate closure member to thereby open the conduit. Similarly, when female member is disconnected from the valve, the spring will return the poppet closure member and the gate closure member to the closed position to thereby seal the conduit. 
     Thus, the valve of the present invention provides two barriers between the conduit and the environment in a single device. Moreover, the second closure member is preferably a gate valve, which is recognized in the flow control industry as being a robust and reliable valve. In addition, since the first and second closure members are connected by the valve stem, the second closure member is actuated upon actuation of the first closure member. Consequently, no need exists for separate control signals to actuate the second closure member. 
     These and other objects and advantages of the present invention will be made apparent from the following detailed description, with reference to the accompanying drawings. In the drawings, the same reference numbers are used to denote similar components in the various embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial cross-sectional view of an exemplary flow completion system having a tubing hanger in which the valve of the present invention is installed; 
     FIG. 2 is a top view of the tubing hanger component of the flow completion system shown in FIG. 1; 
     FIG. 3 is a schematic representation of the flow completion system of FIG. 1 showing a controls bridge connected to the tubing hanger; 
     FIG. 4 is a cross-sectional view of one embodiment of the valve of the present invention shown engaged by a female member of a hydraulic coupling; 
     FIG. 5 is a cross-sectional view of the valve shown in FIG. 4; 
     FIG. 5A is an enlarged view of the poppet closure member component of the valve shown in FIG. 5; 
     FIGS. 6A and 6B are side and front elevational views, respectively, of the lower portion of the stem component of the valve shown in FIG. 4; 
     FIG. 7 is a cross-sectional view of an alternate embodiment of the valve of the present invention; 
     FIG. 8 is a perspective view of another embodiment of the valve of the present invention; 
     FIG. 9 is a cross-sectional view of the valve shown in FIG. 8; 
     FIG. 10 is a cross-sectional view of yet another embodiment of the valve of the present invention; and 
     FIGS. 11A and 11B are sequential views showing the valve of FIG. 10 being actuated by a stab. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The valve of the present invention comprises both a poppet closure member and a gate closure member which are disposed across a common flow passage. Thus, the valve comprises both the primary and the secondary closure members for the flow passage in a single component. Moreover, the poppet and gate closure members are connected by a valve stem and are therefore actuated simultaneously. In the preferred embodiment of the invention, the poppet closure member is adapted to be engaged by the female member of a conventional hydraulic coupling. Thus, when the valve is connected with the female member, the female member will push the poppet and gate closure members into the open position. Furthermore, the valve preferably includes a return biasing means to move the poppet and gate closure members back to the closed position when the female member is disengaged from the valve. 
     The valve of the present invention is therefore particularly useful in isolating a fluid conduit from the environment. When the conduit is connected with another fluid conduit having a female member attached thereto, the valve will allow for the free flow of fluid between the fluid conduits. Alternatively, an external actuator could be employed to engage the valve and thereby allow the fluid in the conduit to flow into a chamber or other controlled environment. Many other variations of the present invention may be envisioned by one of skill in the art. Therefore, while the invention will be described in connection with a service and control conduit in a tubing hanger component of a flow completion system, it should be understood that the present invention should not be limited by this specific application. For example, the valve of the invention could be employed to control the flow of fluid through an annulus bore in a tubing hanger, or through any other type of fluid conduit in general. 
     Referring to FIG. 1, the valve of the present invention, which is indicated generally by reference number  10 , is shown installed in the top end of a service and control conduit  12  extending through a tubing hanger  14  which is landed in a Christmas tree or tubing spool  16  of an exemplary flow completion system  18 . As shown in FIG. 2, the tubing hanger  14  may comprise a plurality of service and control conduits  12  spaced radially about the axial centerline CL of the tubing hanger, and a separate valve  10  (not shown in FIG. 2) may be installed in each of one or more such conduits. When the tubing hanger  14  is not engaged by an external tool, controls bridge or similar device, the valve  10  serves to isolate the service and control conduit  12  from the sea or other external environment. 
     FIG. 3 is a schematic representation of the flow completion system  18  having a controls bridge  20  operatively connected to the tubing hanger  14  and/or the tubing spool  16 . The tubing hanger is shown to include several valves  10  installed in respective service and control conduits  12 . As will be discussed below, the valve  10  does not require a separate actuation signal to move the poppet and gate closure members between the open and closed positions. Therefore, no additional control conduits need to be routed through the controls bridge  20  to the valves. Also, each valve  10  provides a double barrier between service and control conduit  12  and the environment. Therefore, no pressure plug or other temporary closure device needs to be installed in the service and control conduits when the controls bridge, or other device is removed from the tubing hanger or the tubing spool. 
     Referring to FIG. 4, the valve  10  is opened upon being engaged by a female member  22  of a conventional hydraulic coupling. In the example shown, the female coupling member  22  is carried by a tool  24 , such as a tubing hanger running tool. However, the female coupling member  22  may be mounted in any appropriate device which one may desire to operatively connect with the tubing hanger  14  and/or the service and control conduits  12 , such as a tree cap, a controls bridge, or any other appropriate device. The female coupling member  22  communicates with a service and control line  26  in the tool  24 . Thus, when the female coupling member  22  and the valve  10  are properly mated, a fluid path is established between the service and control line  26  in the tool  24  and the service and control conduit  12  in the tubing hanger  14 . 
     Referring to FIG. 5, a preferred embodiment of the valve  10  comprises a cylindrical valve body  28  which is secured within the upper end of the service and control conduit  12  such as by threads  30 , a cylindrical valve bonnet  32  which is preferably threaded into an axial bore  34  that is formed in an upper end of the valve body, an elongated valve stem  36  which is movably mounted in a stepped cylindrical bore  38  that extends axially through the valve bonnet, a poppet type closure member  40  which is connected to an upper end of the valve stem, and a gate type closure member  42  which is connected to a lower end of the valve stem. The valve body  28  is sealed to the service and control conduit  12  with a first annular seal  44 , such as a non-metallic S-type seal, and preferably also a second annular seal  46 , such as a U-shaped lip seal. While the first seal  44  is received within a corresponding recess that is formed in the outer diameter of the valve body  28 , the second seal  46  is preferably held in place by an annular retainer  48  which is secured to the outer diameter of the valve body by a retainer ring  50 . Similarly, the valve bonnet  32  is ideally sealed to the valve body  28  with first and preferably also second annular seals  52  and  54  which are similar to the first and second seals  44  and  46 , respectively. It should be understood, however, that any suitable type, number, or combination of seals could be used for sealing the valve body  28  to the service and control conduit  12  and for sealing the valve bonnet  32  to the valve body. 
     The poppet closure member  40  is ideally formed on a part of the valve stem  36  which is positioned within a portion of the valve bonnet  32  that is adapted to be engaged by a corresponding external coupling member. In the embodiment of the invention depicted in FIG. 5, therefore, the valve bonnet  32  comprises an upper male coupling portion  56  that is adapted to be engaged by the female coupling member  22  shown in FIG.  4 . The male coupling portion  56  terminates in a radially inwardly extending lip  58  which defines an opening  60  through the valve bonnet  32 . The lip  58  forms a poppet seat  62  which optimally has a sealing surface formed thereon. Furthermore, the valve stem  36  comprises an upper section  64  which includes an annular poppet head  66  and an actuating tip  68  that protrudes through the opening  60 . The poppet head  66  includes an upper, preferably conical surface  70  which is adapted to seal against the seat  62  when the poppet valve  40  is in the closed position. 
     The gate closure member  42  comprises a gate  72  which is connected to a lower end  74  of the valve stem  36  that extends into a gate chamber  76  which is formed in the valve body  28 . The gate  72  is slidably disposed between two annular, preferably floating seats  78  and  80  which are mounted in corresponding annular recesses that are formed in the valve body  28 . Each seat  78 ,  80  is ideally biased toward the gate  72  by a Belleville washer or similar means. In addition, each seat  78 ,  80  includes a through bore which is aligned with a lateral branch  82  of a flow passage that extends through the valve  10 , as will be described below. In accordance with the present invention, when the poppet closure member  40  is in the closed position, the gate closure member  42  will also be in a closed position, in which a lateral hole  84  in the gate is offset from the lateral branch  82  of the flow passage, as shown in FIG.  5 . 
     Referring to FIGS. 6A and 6B, the gate  72  of the preferred embodiment of the invention comprises a generally flat, oval shaped insert  86  which is received in a corresponding opening  88  that is formed in the lower end  74  of the stem  36 . The opening  88  is preferably formed through opposing flat portions  90  which are machined into the stem  36 . In addition, the insert  86  preferably protrudes slightly beyond the flat portions  90 . Alternatively, the gate  72  may be a conventional gate which is attached to the lower end  74  of the stem  36  by threads, a T-slot, or other suitable means. 
     Referring again to FIG. 5, the valve stem  36  is sealed to the valve body  28  above the gate chamber  76  by a suitable stem packing  92 . The stem packing  92  is held in position by a gland bushing  94  which in turn is secured within the valve body  28  by the bottom of the valve bonnet  32 . To prevent improper loading of the stem packing  92 , the valve bonnet  32  is threaded into the valve body  28  until a radial flange  96  on the valve bonnet abuts the top of the valve body. The stem packing  92  and the first and second seals  52 ,  54  define a fluid cavity  98  between the valve body  28  and the valve bonnet  32 , and the gland bushing  94  preferably includes one or more holes  100  to allow fluid to flow between the fluid cavity and the cylindrical bore  38  of the valve bonnet. 
     The poppet closure member  40  and the gate closure member  42  are both positioned across a flow passage through the valve  10  which is formed between the opening  60  in the upper end of the valve bonnet  32  and a port  102  in the lower end of the valve body  28 . The flow passage extends from the opening  60  into an annular space between the valve stem  36  and the cylindrical bore  38  of the valve bonnet  32 , through the holes  100  in the gland bushing  94 , and into the fluid cavity  98 . From the fluid cavity  98 , the flow passage extends through a number of bores in the valve body  28  to the port  102 . Accordingly, the flow passage extends through a first longitudinal bore  104  between the fluid cavity  98  and the lateral branch  82 , through the lateral branch  82  and the through bores in the valve seats  78 ,  80 , through a second longitudinal bore  106  which in the embodiment shown extends through a cover plate  108 , through a transverse bore  110  which communicates with the second longitudinal bore  106 , and through a third longitudinal bore  112  which extends between the transverse bore  110  and the port  102 . The first longitudinal bore  104  may actually comprise two or more generally parallel bores which are radially spaced about the axial centerline of the valve  10  and are connected to the lateral branch  82  by one or more transverse branches (not shown). In addition, the second longitudinal bore  106  and the transverse bore  110  may be omitted and the third longitudinal bore  112  instead connected directly to the lateral branch  82 . 
     The cover plate  108  is provided to seal an aperture  114  which is formed in the valve body  28  to facilitate the installation of the valve seats  78 ,  80 . One side of valve body  28  ideally comprises a cutout or recess  116  for receiving the cover plate  108 , which is preferably removably attached to the valve body by bolts (not shown). In addition, suitable annular seals  118  are ideally provided between the cover plate  108  and the valve body  28  around each of the lateral branch  82  and the transverse bore  110 . 
     The valve  10  also includes a return biasing means to bias the poppet closure member  40  and the gate closure member  42  into the closed position. In the embodiment of the invention shown in FIG. 5, the return biasing means comprises a compression spring  120  which is positioned around the stem  36  between the gland bushing  94  and a spring bushing  122  that is connected to the stem. The spring  120  will accordingly bias the stem  36  upwardly into the closed position of the valve  10 . In this position, the conical surface  70  of the poppet head  66  will seal against the seat  62  and the hole  84  in the gate  72  will be offset from the lateral branch  82 . Thus, the flow passage through the valve  10  will be sealed by both the poppet closure member  40  and the gate closure member  42 , and the service and control conduit  12  will therefore be isolated from the environment by these two barriers. 
     Referring again to FIG. 4, when the male coupling portion  56  is engaged by the female coupling member  22 , a portion of the female coupling member will push the actuating tip  68  downward and thereby simultaneously move the poppet head  66  off of the poppet seat  62  and the hole  84  in the gate  72  into alignment with the lateral branch  82 . In this open position of the valve  10 , fluid is now free to flow through the flow passage past both the poppet closure member  40  and the gate closure member  42 . Thus, a fluid connection is established between service and control line  26  in the tool  22  and the service and control conduit  12  in the tubing hanger  14 . In an alternative embodiment of the invention which is not illustrated in the drawings, the poppet closure member  40  or the gate closure member  42  could be replaced by a check valve, a plug valve, or any other suitable valve which is actuated by axial movement of a valve stem  36 . 
     Referring now to FIG. 7, an alternate embodiment of the valve of the present invention is illustrated. The valve of this embodiment, which is indicated generally by reference number  200 , is similar in many respects to the valve  10  discussed above. However, the gland bushing  94  of the valve  200  does not comprise any holes to allow fluid to pass from the fluid cavity  98  into the cylindrical bore  38  of the valve bonnet  32 . Instead, the lower end of the valve bonnet  32  includes one or more radial slots  124  that extend between the fluid cavity  98  and the cylindrical bore  38 . The valve  200  is similar to the valve  10  in all other material respects. 
     Another embodiment of the valve of the present invention is shown in FIGS. 8 and 9. The valve of this embodiment, which is indicated generally by reference number  300 , is also similar in many respects to the valve  10  discussed above. In this embodiment, however, the valve body  28  is preferably sealed to the service and control conduit  12  by a suitable packing  126 , and the valve bonnet  32  is preferably sealed to the valve body by a similar packing  128 . The packing  126  is ideally retained on the outer diameter of the valve body  28  by a retainer sleeve  130  which in turn is secured to the valve body by a retainer ring  132 . In addition, the packing  128  is trapped between the valve body  28  and the outer diameter of the valve bonnet  32  by an upper axial extension  134  of the gland bushing  94 . Also, the gland bushing  94  includes a number of axial holes  136  to allow for fluid communication between the fluid cavity  98  and the cylindrical bore  38  of the valve bonnet  32 . 
     Furthermore, in order to simplify the construction of the valve  300 , the valve stem  36  includes an upper portion  138  which is threadedly connected to a lower portion  140 . In addition, the spring bushing  122  is preferably formed integrally with the upper portion  138 . Moreover, the spring bushing  122  of this embodiment may be provided with a number of axial apertures  142  to facilitate the passage of fluid past the spring bushing. 
     The flow passage of valve  300  is similar to the portion of the flow passage in valve  10  which extends between the gate cavity  76  and the opening  60  in the valve bonnet  32 . However, after passing through the first longitudinal bore  104  and the lateral passage  82 , the fluid exits a port  144  which is formed in the cover plate  108 . The fluid then enters an annular portion of the service and control conduit  12  that is defined between the packing  126  and the outer diameter of the valve body  28 . In the embodiment of the invention shown in FIGS. 8 and 9, the a lower portion  146  of the valve body  28  is threaded into the service and control conduit  12 . Thus, the valve body  28  preferably includes a suitable bore  148  to facilitate the passage of the fluid past the lower portion  146 . Of course, if the valve body  28  is secured to the service and control conduit  12  above the port  144 , the lower portion  146 , and thus the bore  148 , may be omitted. 
     Referring now to FIG. 10, an embodiment of the valve of the present invention is depicted which may be conveniently actuated by a stab that is mounted on a tubing hanger running tool, a tree or any other suitable component. The valve of this embodiment, which is indicated generally by reference number  400 , is shown to comprise a valve stem  150  which is slidably received in a retainer sleeve  152  that is secured in a preferably cylindrical valve cavity  154  by a retainer nut  156 . The retainer sleeve  152  is ideally sealed to the valve cavity  154  by a suitable seal  158 , and the valve stem  150  is optimally sealed to the retainer sleeve by an appropriate packing  160 . The valve cavity  154  is preferably formed coaxially with a portion of the service and control conduit  12  that extends to the top or outer surface of the tubing hanger  14 . In addition, the valve cavity  54  is shown to intersect preferably two spaced apart generally lateral upper and lower branches  162 ,  164  of the service and control conduit  12 . Furthermore, the valve  400  comprises a poppet closure member  166  which is connected to the top of the valve stem  150  and is preferably positioned to control the flow through the upper branch  162 , and a gate closure member  168  which is connected to the lower end of the valve stem and is preferably positioned to control the flow through the lower branch  164 . 
     The poppet closure member  166  comprises a generally disc-shaped poppet head  170  which is connected to the top of the valve stem by suitable means, such as one or more cap screws (not shown). The poppet head  170  includes a radially outwardly facing sealing lip  172  that is adapted to engage a corresponding poppet seat  174  which is installed or formed in a top branch  176  of the service and control conduit  12 . The poppet seat  174  of this embodiment is in the form of a cylindrical sealing surface which defines an opening through the top branch  176 , and when the valve  400  is in the closed position, the sealing lip  172  will seal against the sealing surface  174  and thereby block the passage of fluid between the top branch  176  and the upper branch  162 . 
     The gate closure member  168  comprises a gate  178  which is connected to the bottom of the valve stem  150  by suitable means, such as a yoke and pin connection  180 . The gate  178  is slidably disposed between two valve seats  182 ,  184  which are mounted in corresponding recesses that extend laterally from the valve cavity  154  into the tubing hanger  14 . Each seat  182 ,  184  is preferably sealed to its corresponding recess by a suitable seal (not shown), and each seat includes a through bore which is aligned with the lower branch  164  of the service and control conduit  12 . When the valve  400  is in the closed position, a transverse through hole  186  in the gate  178  will be offset from the lower branch  164  and thereby block the passage of fluid through the lower branch. 
     The valve  400  further comprises a return biasing means for urging the valve stem  150  into the closed position. In the embodiment of the invention depicted in FIG. 10, the return biasing means comprises a compression spring  188 . The compression spring  188  is operatively engaged between an annular step  190  that is formed in the valve cavity  154  and a flange  192  that extends radially from the valve stem  150 . Upward movement of the valve stem is restricted by the engagement of the flange  192  with the bottom of the retainer sleeve  152 . 
     The operation of the valve  400  will now be described with reference to FIGS. 11A and 11B. In the rest position of the valve  400 , both the poppet closure member  166  and the gate closure member  168  are closed. These closure members therefore provide two barriers between the service and control conduit  12  and the external environment. In order to open the valve  400 , a seal stab  194  which is mounted on a tubing hanger running tool, a tree or any other suitable component is lowered into the top branch  176  of the service and control conduit  12  and against the poppet head  170 . The stab  194  may be either fixed or hydraulically extendable and ideally includes an axial bore  196  and a number of lateral apertures  198  extending between the axial bore and the outer diameter of the stab. Further downward movement of the stab  194  will push the poppet head  170 , and thus the valve stem  150  downward into the open position of the valve  400 , which is shown in FIG.  11 B. In this position, the sealing lip  172  of the poppet head  170  is positioned below at least a portion of the upper branch  162 , and the through hole  186  in the gate  178  is aligned with the lower branch  164 . Consequently, fluid within the axial bore  196  will flow through the apertures  198 , past the poppet head  170  through the upper branch  162 , through an intermediate branch that extends between the upper and lower branches  162 ,  164  (which is shown in phantom in FIG.  11 B), through the lower branch  164  and into the remainder of the service and control conduit  12 . Of course, the fluid may flow in the opposite direction if need be. 
     It should be recognized that, while the present invention has been described in relation to the preferred embodiments thereof, those skilled in the art may develop a wide variation of structural and operational details without departing from the principles of the invention. For example, the various elements shown in the different embodiments may be combined in a manner not illustrated above. Therefore, the appended claims are to be construed to cover all equivalents falling within the true scope and spirit of the invention.