Safety valve actuator and pilot system

• US 4,240,463 A
• Filed: 07/27/1979
• Issued: 12/23/1980
• Est. Priority Date: 07/27/1979
• Status: Expired due to Term

• Current Assignee: Otis Engineering Corporation (Halliburton Company)
• Original Assignee: Otis Engineering Corporation (Halliburton Company)
• Inventors: Moore, Allen D.
• Primary Examiner(s): Weakley, Harold W.
• Application Number:
  US06/061,497
• Time in Patent Office: 515 Days
• Field of Search: 137/492.5, 137/488, 137/458
• US Class Current: 137/492.5
• CPC Class Codes: F16K 17/00 Safety valves; Equalising valves, e.g. pressure relief valves
• CPC Class Codes: F16K 17/10 with auxiliary valve for fluid operation of the main valve
• CPC Class Codes: Y10T 137/7725 Responsive to both high and low pressure or velocity
• CPC Class Codes: Y10T 137/7762 Fluid pressure type
• CPC Class Codes: Y10T 137/777 Spring biased

Abstract

A safety valve actuator and pilot system for emergency closure of a flow line for fluids such as oil and gas including a hydraulic valve actuator connected on a valve in a flow line for opening and closing the valve, a pressure sensing pilot valve communicating with the flow line for directing operating fluid into the hydraulic actuator in response to a predetermined pressure change in the flow line, a closed fluid storage system connected with the hydraulic actuator for containing exhausted operating fluid and redirecting the fluid back into the flow line, and flow connections for operating the actuator to reopen the safety valve. One form of the system operates directly from flow line pressure for response to the predetermined high pressure. Another form of the system includes an operating fluid storage tank and functions in response to either a high or high and low pressure in the flow line.

Claims

1. A safety valve actuator and pilot valve system for closing and reopening a normally open gate valve in a flow line responsive to a predetermined pressure value in said flow line comprising:

a hydraulic valve actuator coupled with said safety valve for closing said safety valve responsive to a fluid pressure increase communicated to said actuator from said flow line;

pressure responsive pilot valve means connected with said flow line;

a conduit from said pilot valve means to said valve actuator for conducting operating fluid pressure to said actuator when said pilot valve functions to close said safety valve;

a conduit from said flow line to said valve actuator for conducting pressure fluid from said flow line to reopen said safety valve; and

a conduit from said valve actuator to said flow line to return operating fluid from said actuator to said flow line after said operating fluid has been used to close said safety valve.

2. The safety valve actuator and pilot valve system of claim 1 wherein said pilot valve means is operable responsive to a predetermined high pressure value in said flow line.

3. A safety valve actuator and pilot valve system in accordance with claim 1 wherein said pilot valve means is operable responsive to either of a predetermined high pressure value in said flow line and a predetermined low pressure value in said flow line, including an operating fluid reservoir, a conduit from said pilot valve means to said reservoir for flowing operating fluid from said reservoir through said pilot valve means to said actuator, and a conduit from said flow line to said reservoir for charging said reservoir with operating fluid from said flow line.

4. A safety valve actuator and pilot valve system in accordance with claim 3 including a fluid velocity responsive check valve between said pilot valve means and said flow line, and a fluid velocity responsive check valve between said actuator and said flow line in said conduit for returning operating fluid from said actuator back to said flow line.

5. A safety valve actuator and pilot valve system in accordance with claim 4 wherein said pilot valve means includes a first low-pressure responsive monitor-actuator pilot valve, a second high-pressure responsive monitor-actuator pilot valve, and a third actuator pilot valve connected with said first and second pilot valves and operable responsive to either of said first and second pilot valves to release operating fluid pressure from said reservoir to said safety valve actuator.

6. A safety valve actuator and pilot valve system for closing and reopening a normally open gate valve in a flow line responsive to a predetermined pressure value in said flow line comprising:

a hydraulic valve actuator for connection on said safety valve including a piston rod and piston in a cylinder, said cylinder being connectible on the housing of said gate valve and said piston rod being connectible with the valve stem of said gate valve, spring means in said cylinder engaged with a first side of said piston biasing said piston in a first valve opening direction, said piston and said piston rod being movable in a second opposite valve closing direction responsive to operating fluid injected into said cylinder on the second opposite side of said piston;

a high pressure responsive pilot valve connected into said flow line;

a conduit connected from said pilot valve into said cylinder on said second side of said piston for conducting operating fluid from said flow line to said cylinder responsive to operation of said pilot valve at a predetermined high pressure value in said flow line;

a valve in said conduit from said pilot valve to said cylinder for shutting off flow in said conduit;

a conduit including a valve from said flow line into said cylinder on said first side of said piston for introducing operating fluid from said flow line into said cylinder for opening said gate valve;

a pump and fluid reservoir system for receiving operating fluid from said cylinder and returning said fluid to said flow line;

a conduit including a velocity check valve from said cylinder on said second side of said piston to said pump and fluid reservoir system;

a conduit from said cylinder on said first side of said piston to said pump and fluid reservoir system; and

a conduit from said pump and fluid reservoir system to said flow line for reintroducing operating fluid into said flow line from said cylinder on both said first and second side of said piston.

7. A safety valve actuator and pilot valve system for closing and reopening a normally open gate valve in a flow line responsive to either of a predetermined high pressure value and a predetermined low pressure value in said flow line comprising:

a hydraulic valve actuator for opening and closing said gate valve including a cylinder having means for mounting on the housing of said gate valve defining a fluid pressure tight chamber, a piston movable in said cylinder, a piston rod connected with said piston and having means for connection with the valve stem of said gate valve for opening and closing said gate valve responsive to operating fluid pressure on said piston, and a spring in said cylinder engaged between one end of said cylinder and one side of said piston biasing said piston and said piston rod in a valve opening direction;

an operating fluid storage reservoir;

a conduit including a velocity check valve connected with said reservoir and connectible into said flow line for supplying said reservoir with operating fluid from said flow line;

an actuator pilot valve connected into said reservoir;

a conduit including a cut-off valve from said actuator pilot to said cylinder on a second side of said piston for supplying operating fluid from said reservoir into said cylinder against said second side of said piston for closing said gate valve responsive to operation of said actuator pilot conduit from said flow line to said actuator pilot;

a low-pressure monitor-actuator pilot valve connected into said actuator pilot valve between said actuator pilot valve and said velocity check valve;

a high-pressure monitor-actuator pilot valve connected into said actuator pilot valve between said actuator pilot valve and said velocity check valve;

a conduit including a cut-off valve from said operating fluid storage reservoir into said gate valve actuator cylinder on said first side of said piston for supplying operating fluid from said storage reservoir to reopen said gate valve;

a pump and operating fluid storage system for receiving and reintroducing into said flow line operating fluid employed in said gate valve actuator for closing and reopening said gate valve;

a conduit including a velocity check valve from said gate valve actuator cylinder on said second side of said piston to said operating fluid storage and pump system;

a conduit from said gate valve actuator cylinder on said first side of said piston including a cut-off valve to said operating fluid pump and storage system; and

a conduit from said operating fluid pump and storage system including a cut-off valve connectible into said flow line for reintroducing into said flow line operating fluid employed in closing and reopening said gate valve in said gate valve actuator.

8. A safety valve actuator and pilot valve system for closing and reopening a normally open gate valve in a flow line responsive to a predetermined pressure valve in said flow line comprising:

a hydraulic valve actuator coupled with said safety valve for closing said safety valve responsive to a fluid pressure increase communicated to said actuator from said flow line;

pressure responsive pilot valve means connected with said flow line;

a conduit from said pilot valve means to said valve actuator for conducting operating fluid pressure to said actuator when said pilot valve functions to close said safety valve;

a conduit from said flow line to said valve actuator for conducting pressure fluid from said flow line to reopen said safety valve; and

valve means from said valve actuator to vent spent operating fluid after said operating fluid has been used to close said safety valve.

9. The safety valve actuator and pilot valve system of claim 8 wherein said pilot valve means is operable responsive to a predetermined high pressure value in said flow line.

10. A safety valve actuator and pilot valve system in accordance with claim 8 wherein said pilot valve means is operable responsive to either of a predetermined high pressure value in said flow line and a predetermined low pressure value in said flow line, including an operating fluid reservoir, a conduit from said pilot valve means to said reservoir for flowing operating fluid from said reservoir through said pilot valve means to said actuator, and a conduit from said flow line to said reservoir for charging said reservoir with operating fluid from said flow line.

11. A safety valve actuator and pilot valve system in accordance with claim 10 including a fluid velocity responsive check valve between said pilot valve means and said flow line, and said valve means from said valve actuator includes a velocity check valve.

12. A safety valve actuator and pilot valve system in accordance with claim 11 wherein said pilot valve means includes a first low-pressure responsive monitor-actuator pilot valve, a second high-pressure responsive monitor-actuator pilot valve, and a third actuator pilot valve connected with said first and second pilot valves and operable responsive to either of said first and second pilot valves to release operating fluid pressure from said reservoir to said safety valve actuator.

13. A safety valve actuator and pilot valve system for closing and reopening a normally open gate valve in a flow line responsive to a predetermined pressure value in said flow line comprising:

a hydraulic valve actuator for connection on said safety valve including a piston rod and piston in a cylinder, said cylinder being connectible on the housing of said gate valve and said piston rod being connectible with the valve stem of said gate valve, spring means in said cylinder engaged with a first side of said piston biasing said piston in a first valve opening direction, said piston and said piston rod being movable in a second opposite valve closing direction responsive to operating fluid injected into said cylinder on the second opposite side of said piston;

a high pressure responsive pilot valve connected into said flow line;

a conduit connected from said pilot valve into said cylinder on said second side of said piston for conducting operating fluid from said flow line to said cylinder responsive to operation of said pilot valve at a predetermined high pressure value in said flow line;

a valve in said conduit from said pilot valve to said cylinder for shutting off flow in said conduit;

a conduit including a valve from said flow line into said cylinder on said first side of said piston for introducing operating fluid from said flow line into said cylinder for opening said gate valve; and

vent lines from said cylinder on each side of said piston including a velocity check valve from said vent line on said second side of said piston and a shut-off valve in said vent line on said first side of said piston.

14. A safety valve actuator and pilot valve system for closing and reopening a normally open gate valve in a flow line responsive to either of a predetermined high pressure value and a predetermined low pressure value in said flow line comprising:

a hydraulic valve actuator for opening and closing said gate valve including a cylinder having means for mounting on the housing of said gate valve defining a fluid pressure tight chamber, a piston movable in said cylinder, a piston rod connected with said piston and having means for connection with the valve stem of said gate valve for opening and closing said gate valve responsive to operating fluid pressure on said piston, and a spring in said cylinder engaged between one end of said cylinder and one side of said piston biasing said piston and said piston rod in a valve opening direction;

an operating fluid storage reservoir;

a conduit including a velocity check valve connected with said reservoir and connectible into said flow line for supplying said reservoir with operating fluid from said flow line;

an actuator pilot valve connected into said reservoir;

a conduit including a cut-off valve from said actuator pilot to said cylinder on a second side of said piston for supplying operating fluid from said reservoir into said cylinder against said second side of said piston for closing said gate valve responsive to operation of said actuator pilot conduit from said flow line to said actuator pilot;

a low-pressure monitor actuator pilot valve connected into said actuator pilot valve between said actuator pilot valve and said velocity check valve;

a high-pressure monitor-actuator pilot valve connected into said actuator pilot valve between said actuator pilot valve and said velocity check valve;

a conduit including a cut-off valve from said operating fluid storage reservoir into said gate valve actuator cylinder on said first side of said piston for supplying operating fluid from said storage reservoir to reopen said gate valve;

a vent line including a velocity check valve from said gate valve actuator cylinder on said second side of said piston and a vent line from said gate valve actuator cylinder on said first side of said piston including a cut-off valve.