Sand lock valve

Abstract

A singular piston included behind a valve seat within a gate valve assembly can be energized by external pressure through a hydraulic port within the valve body. When the back side of the singular piston is energized, the singular piston applies force in one direction against the adjacent valve seat, valve gate, opposing valve seat and valve seat pocket in both the valve open position and the valve closed position to block any unwanted matter from moving into the valve backside cavity. A singular piston has a pressure sealing surface and a piston pocket with an adjacent pressure sealing surface that allows the valve to seal in the closed position with the contained fluid bore pressure against the opposing valve body flow path side to the piston without the piston being energized.

1 - 13 . (canceled) 
     
     
         14 . A gate valve comprising:
 a body defining a bore, a channel, and a port, the bore defined through the body for fluid flow, the channel defined in the body relative to the bore, the port defined in the body for communication of hydraulic pressure;   first and second seat surfaces disposed in the bore respectively on first and second sides of the channel;   a gate being movable in the channel in sealing engagement relative to the first and second seat surfaces and being configured to selectively permit and prevent the fluid flow through the bore; and   a piston surface being sealed in communication with the hydraulic pressure from the port, the piston surface being movable relative to the first seat surface in response to the hydraulic pressure and being configured to adjust a force of the sealing engagement at least between the first seat surface and the gate.   
     
     
         15 . The gate valve of  claim 14 , wherein the bore defines first and second recesses being recessed from the bore and disposed respectively on the first and second sides of the channel, the first recess having a first seat disposed therein, the first seat having the first seat surface adjacent to the gate, the second recess having a second seat disposed therein, the second seat having the second seat surface disposed adjacent to the gate. 
     
     
         16 . The gate valve of  claim 15 , wherein each of the first and second seats in the respective first and second recesses comprises a seal disposed about an outside dimension of the respective seat and being configured to seal with the respective recess. 
     
     
         17 . The gate valve of  claim 15 , wherein the gate defines a gate passage therethrough; and wherein each of the first and second seats defines a seat passage therethrough, the seat passages communicating with the bore, the gate being movable relative to the first and second seat surfaces of the first and second seats at least between first and second states, the gate in the first state having the gate passage aligned with the seat passages, the gate in the second state having the gate passage misaligned with the seat passages. 
     
     
         18 . The gate valve of  claim 15 , wherein the port defined in the body communicates with a pocket defined in the body adjacent to the first recess, the pocket having the piston surface sealably disposed therein. 
     
     
         19 . The gate valve of  claim 18 , comprising a piston disposed in the pocket, a first portion of the piston being configured to contact the first seat, a second portion of the piston being sealed in the pocket and having the piston surface exposed to the hydraulic pressure from the port, the first portion of the piston being urged into contact with the first seat in response to the hydraulic pressure exposed against the piston surface. 
     
     
         20 . The gate valve of  claim 19 , wherein the first portion of the piston comprises a crown configured to contact the first seat; and wherein the second portion of the piston comprises a skirt extending from the crown. 
     
     
         21 . The gate valve of  claim 19 , wherein the pocket has an internal facing wall that is recessed from the bore and has an external facing wall that faces the internal facing wall and is radially separated from the internal facing wall; and wherein the piston comprises:
 a first seal in sealed engagement with the internal facing wall of the pocket; and   a second seal in sealed engagement with the external facing wall of the pocket.   
     
     
         22 . The gate valve of  claim 21 , wherein the first seal comprises a first O-ring seal disposed about an outside surface of the piston; and wherein the second seal comprises a second O-ring seal disposed about an inside surface of the piston. 
     
     
         23 . The gate valve of  claim 19 , further comprising a seal configured to seal between the first portion of the piston and the first seat. 
     
     
         24 . The gate valve of  claim 23 , wherein the seal comprises an annular seal disposed in an annular groove defined on an end of the first seat. 
     
     
         25 . The gate valve of  claim 14 , further comprising a control valve being connected to the port and being configured to control communication of the hydraulic pressure with the piston surface. 
     
     
         26 . A sealing apparatus for use in a gate valve having first and second seats disposed in a bore of a body of the gate valve and disposed on opposing sides of a gate movable in the gate valve relative to the first and second seats, the sealing apparatus comprising:
 a control valve being configured to communicate hydraulic pressure to an area of the bore adjacent the first seat; and   a piston being insertable in the bore in the area adjacent to the first seat, the piston having first and second surfaces, the first surface being configured to contact the first seat, the second surface being configured to communicate with the hydraulic pressure from the control valve, the piston being movable in a direction of the bore relative to the first seat in response to the hydraulic pressure from the control valve against the second surface of the piston.   
     
     
         27 . The sealing apparatus of  claim 26 , wherein the piston comprises:
 a crown having the first surface;   a skirt extending from the crown opposite the first surface and having the second surface;   a first seal disposed about an outside dimension of the piston and configured to sealably engage with an internal facing wall of the area of the bore; and   a second seal disposed about an inside dimension of the skirt on the piston and configured to sealably engage with an external facing wall of the area of the bore.   
     
     
         28 . A method to configure a gate valve having first and second seats disposed in a bore of a body of the gate valve, the first and second seats disposed in recesses on opposing sides of a gate, the gate being movable in the gate valve in sealing engagement relative to the first and second seats, the method comprising:
 defining an annular pocket adjacent to the recess for the first seat;   defining a port in the body to communicate hydraulic pressure with the annular pocket;   installing a piston surface in sealed engagement in the annular pocket and exposed in fluid communication with the port; and   installing the first seat in the recess of the bore between the gate and the piston surface.   
     
     
         29 . The method of  claim 28 , wherein defining the annular pocket in the bore adjacent to the recess for the first seat comprises:
 forming an internal facing wall of the annular pocket that is adjacent to the recess for the first seat and that is recessed from the bore; and   forming an external facing wall of the annular pocket that faces the internal facing wall and that is radially spaced from the internal facing wall.   
     
     
         30 . The method of  claim 29 , wherein installing the piston surface in sealed engagement in the annular pocket and exposed in fluid communication with the port comprises:
 engaging an external seal of the piston surface with the internal facing wall of the annular pocket; and   engaging an internal seal of the piston surface with the external facing wall of the annular pocket.   
     
     
         31 . A method of operating a gate valve having first and second seat surfaces disposed in a bore of a body of the gate valve, the first and second seat surface disposed on opposing sides of a gate, the gate being movable in the gate valve, the method comprising:
 moving the gate in the gate valve in sealing engagement relative to the first and second seat surfaces in the bore;   communicating hydraulic pressure via a port defined in the gate valve against a piston surface disposed adjacent to the first seat surface in the bore; and   adjusting a force in the sealing engagement at least between the first seat surface and the gate by urging the first seat surface against the gate in response to the hydraulic pressure communicated against the piston surface.   
     
     
         32 . The method of  claim 31 , wherein communicating the hydraulic pressure via the port defined in the gate valve against the piston surface disposed adjacent to the first seat surface in the bore comprises:
 communicating the hydraulic pressure via the port to an annular pocket defined in the body; and   sealing the hydraulic pressure in the annular pocket against the piston surface by using an external seal of the piston surface engaged with an internal facing wall of the annular pocket and using an internal seal of the piston surface engaged with an external facing wall of the annular pocket.   
     
     
         33 . The method of  claim 31 , wherein adjusting the force in the sealing engagement at least between the first seat surface and the gate by urging the first seat surface against the gate in response to the hydraulic pressure communicated against the piston surface comprises moving the piston surface in a direction of the bore toward the first seat surface in response to the hydraulic pressure communicated via the port to the piston surface.