GREASE PRESSURE RELIEF SYSTEM

Abstract

A check valve bleed assembly eliminates the requirement for a person to enter the red zone when bleeding the grease out of a gate or other valve. A gas or other fluid is provided to the check valve bleed assembly. The gas or other fluid acts upon the surface driving a pin into the associated check valve with sufficient force to overcome the resistance of the object sitting on a seat and moves the object off of the seat. The force is maintained as long as is necessary. Usually, the check valve is held open until the gate transitions into the gate's associated gate recess thereby displacing the grease within the gate recess through the check valve, into the check valve bleed assembly, and finally to a waste collection tube. In some embodiments a gate valve greasing access port is included in the check valve bleed assembly such that grease may be injected into the check valve bleed assembly.

Claims

1. A gate valve bleed system comprising: a gate valve having a bleed port; at least one check valve having a ball and a seat; wherein the check valve is affixed to the bleed port; wherein the check valve prevents fluid flow through the gate valve bleed port when the check valve ball is on the check valve seat; a piston, at least one rod, and a waste collection port; wherein the piston is acted upon by an externally supplied fluid to create a first force; wherein the first force is directed through the at least one rod to displace the ball from the seat.

2. The gate valve bleed system of claim 1 wherein, a second fluid within the gate valve is in fluid communication with the waste collection port only when the rod displaces the ball from the seat.

3. The gate valve bleed system of claim 1 wherein, the first force acting upon the piston is removed.

4. The gate valve bleed system of claim 3 further comprising a bias device.

5. The gate valve bleed system of claim 4 wherein, the bias device supplies a second force to the rod moving the rod out of contact with the ball.

6. The gate valve bleed system of claim 1 wherein, the piston includes a position indicator.

7. A gate valve bleed system comprising: a gate valve having a bleed port; a fluid flow path from the bleed port to a waste collection port; a second fluid flow path from a grease injection port to the bleed port; a first check valve; wherein the first check valve prevents fluid flow from the bleed port past the first check valve when the first check valve is closed; a second check valve in the second fluid flow path preventing fluid flow past the second check valve when the second check valve is closed; a third check valve in the first fluid flow path between the waste collection port and the second fluid flow path; wherein grease flowing into the second fluid flow path from an exterior of the gate valve opens the first and second check valves while closing the third check valve

8. A gate valve bleed system comprising: a gate valve having a bleed port; a first fluid flow path from the bleed port to a waste collection port; at least one check valve; wherein the check valve prevents fluid flow through the bleed port when the check valve is closed; a piston and at least one rod; wherein the piston is acted upon by an externally supplied fluid in a second fluid flow path to create a first force; wherein the first force is directed through the at least one rod to open the first check valve.

9. The gate valve bleed system of claim 8 wherein, a second fluid within the gate valve is in fluid communication through the first fluid flow path with the waste collection port only when the first check valve is open.

10. The gate valve bleed system of claim 8 wherein, the first force acting upon the piston is removed.

11. The gate valve bleed system of claim 10 further comprising a bias device.

12. The gate valve bleed system of claim 11 wherein, the bias device supplies a second force to the rod allowing the first check valve to close.

13. The gate valve bleed system of claim 8 wherein, the piston includes a position indicator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a side view of a gate valve having a check valve bleed assembly where the gate prevents fluid access through the gate valve throughbore.

[0009] FIG. 2 is a side view of a gate valve having a check valve bleed assembly where the gate allows fluid access through the gate valve throughbore.

[0010] FIG. 3 is a side view of a check valve bleed assembly having a closed fluid flow path through the check valve bleed assembly.

[0011] FIG. 4 is a side view of a check valve bleed assembly having an open fluid flow path through the check valve bleed assembly.

[0012] FIG. 5 is a side view of a check valve bleed assembly having an open grease injection flow path through the check valve bleed assembly.

DETAILED DESCRIPTION

[0013] The description that follows includes exemplary apparatus, methods, techniques, or instruction sequences that embody techniques of the inventive subject matter. However, it is understood that the described embodiments may be practiced without these specific details.

[0014] FIG. 1 is a representation of an embodiment of the current invention. A gate valve 100 includes gate 110. Gate 110 has a blocking portion 112 and open portion 114. The gate valve 100 has an upper end 102 and a lower end 104. Additionally, gate valve 100 includes a 1st gate cavity 106 and a 2.sup.nd gate cavity 108. As shown, the gate 100's blocking portion 112 sits across throughbore 120 preventing fluid access through throughbore 120 between the upper end 102 of the gate valve 100 and the lower end 104 of the gate valve 100. Gate valve 110 is positioned within the 2.sup.nd gate cavity 108. The gate valve 100 also includes a 1.sup.st bleed port 130 and a 2.sup.nd bleed port 132. The 1st bleed port 130 and the 2.sup.nd bleed port 132 are each provided with a check valve bleed assembly 134 and 136 respectively. Generally, the 1.sup.st gate cavity 106 and the 2.sup.nd gate cavity 108 are filled with grease.

[0015] In order to shift the gate valve 100 from the currently shown closed condition the gate 110 must be shifted such that the blocking portion 110 no longer sits across throughbore 120 and that open portion 114 is aligned with the throughbore 120 allowing fluid access between the upper portion 102 of gate valve 100 and the lower portion 104 of gate valve 100 as is shown in FIG. 2.

[0016] FIG. 2 depicts the gate valve 100, from FIG. 1, with the gate 110 shifted so that open portion 114 is aligned with the throughbore 120 allowing fluid access between the upper end 102 of gate valve 100 and the lower end 104 gate valve 100. The gate 110 has been shifted such that blocking portion 112 of the gate 110 is within the 1.sup.st cavity 106. However, the 1.sup.st cavity 106 is filled with grease which is an incompressible fluid therefore prior to shifting the gate 110 into the 1.sup.st cavity 106 a provision must be made for the grease to exit the 1.sup.st cavity 106 either prior to or as the blocking portion 112 of the gate 110 shifted into the 1.sup.st cavity 106. In most instances as the blocking portion 112 of the gate 110 is shifted into the 1.sup.st cavity 106 a like amount of grease is displaced from the 1.sup.st cavity 106 through port 130.

[0017] In most instances when the throughbore 120 is pressurized, usually with fracking fluid, all fluid ports that provide a fluid path to the throughbore 120 must be sealed. In order to seal bleed ports 130 and 132 generally a check valve bleed assembly such as check valve bleed assemblies 134 and 136 are affixed, usually by threads, into bleed ports 130 and 132. Check valve bleed assemblies 134 and 136 include a check valve that remains closed unless the check valve bleed assembly is actuated.

[0018] FIG. 3 is a check valve bleed assembly 134 and it's normally an actuated state. The check valve bleed assembly 134 includes at least a 1.sup.st check valve 202. At the lower end 204 of the check valve 202 are threads 206 which may be threaded into port 130. The check valve 202 generally includes a seat 210, a ball 212, and a biasing device such as a spring 214. The spring 214 provides a force to push the ball 212 into the seat 210. As fluid from bleed port 130 proceeds into the check valve 210 the fluid will act upon the ball 212 to add additional force to the spring 214 to push the ball 212 into the seat 210. At the upper end of the check valve is port 208. Port 208 provides fluid access to passageway 220. Passageway 220 in turn is fluidly connected to port 222 and port 224.

[0019] The check valve bleed assembly 134 also has a port 230. Port 230 is fluidly connected to chamber 240 by passageway 232. In this instance the fluid may be a gas or a liquid such as hydraulic fluid within chamber 240 is piston 250. Piston 250 has a lower rod 252 that extends into passageway 220. In some instances piston 250 has an upper rod 254 that extends through cap 242 to the exterior of the check valve bleed assembly 134. Within chamber 240 and below piston 250 is a piston biasing device 256, in this instance a spring. In other instances the piston biasing device 256 may be a compressible fluid or gas such as nitrogen. In certain instance rod 254 may be used to indicate the position of the check valve, ie whether the ball 312 is off of the seat 310 and open or the ball 312 is on the seat 310 and closed.

[0020] When not actuated spring 256 pushes piston 250 towards the upper end of chamber 240 thereby moving lower rod 252 out of contact with ball 212. With lower rod 250 removed from contact with ball 212 biasing device 214 may push valve 212 into contact with seat 210 and with any additional fluid pressure from within bleed port 130 seals in the pressure within bleed port 130. In certain instances the lower rod 252 may remain in contact with ball 212 relying upon biasing device 214 to provide sufficient force to move ball 212 into contact with seat 210 despite the added resistance of lower rod 252, piston 250, and any fluid within chamber 240 above piston 250.

[0021] FIG. 4 depicts the check valve bleed assembly 134 in its actuated condition. Fluid pressure is provided through port 230, into passageway 232, and then into chamber 240 the fluid pressure acts upon piston 250 and provides sufficient force to move the piston 250 downwards in opposition to the piston biasing device 256. As the piston 250 moves downwards rod 252 is also forced downwards and into contact with ball 212. Ball 212 is also forced downwards in opposition to biasing device 214. As ball 212 is forced downwards it no longer contacts seat 210 thereby opening a fluid passageway. Any grease or other fluid within bleed port 130 may then move from bleed port 130 into check valve 202, around ball 212, into passageway 220, further moving up passageway 220 where it enters port 222 exiting the check valve bleed assembly 134 into a waste tube 221 as indicated by arrow 203 and 205.

[0022] FIG. 5 is an alternative arrangement of a check valve bleed assembly 300 that includes a grease injection system 350. The check valve bleed assembly 300 includes at least a 1.sup.st check valve 302. At the lower end 304 of the check valve 302 are threads 306 which may be threaded into port 330. The check valve 302 generally includes a seat 310, a ball 312, and a biasing device such as a spring 314. The spring 314 provides a force to push the ball 312 into the seat 310. At the upper end of the check valve is a port 308. Port 308 provides fluid access between passageway 320 and port 330. Passageway 320 in turn is fluidly connected to port 353. Within passageway 320 is a seat 355. Rod 352 is within passageway 320 and includes a shoulder 357. Generally, when the check valve bleed assembly 300 is not actuated shoulder 357 will contact seat 355 and act as a check valve preventing fluid from proceeding through passageway 322 port 322. In general any check valve could be placed at the location of the seat and rod shoulder assembly provided that force could be applied thought the assembly from the rod above to another rod below in order to move the ball 312 off of the seat 310 when required.

[0023] Generally, when the grease injection system 350 is actuated grease is supplied through tube 360. The high-pressure grease applies force to the ball 362 and moves ball 362 off of seat 364. With the ball 362 displaced from seat 364 the grease can move from tube 360 around ball 362 and into port 353. The grease then moves from port 353 in the passageway 320. Seat 355 and shoulder 357 act as a check valve to prevent grease from moving further up in passageway 320 towards port 322. Grease moves from passageway 320 into passageway 308 within check valve 302 where again the grease supply sufficient pressure to force ball 312 off of seat 310. The grease is then able to flow around ball 312 through check valve 302 into bleed port 330 and finally into a 1.sup.st or 2.sup.nd cavity within a gate valve.

[0024] Plural instances may be provided for components, operations or structures described herein as a single instance. In general, structures and functionality presented as separate components in the exemplary configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements may fall within the scope of the inventive subject matter.