Partial stroke testing system coupled with fuel control valve

Abstract

A system for on-line testing of an emergency shut-off valve includes a first emergency shut-off valve (first valve) and a flow control valve (second valve), with the system being configured to allow the second valve to serve as a combination flow control and second emergency shut-off valve. A subsystem is also provided for testing the first valve without fully closing the first valve in response to a signal from the control. In this subsystem, a solenoid valve bleeds off pressurized fluid to move the first valve from a fully opened to a partially closed position. A bypass around the second valve allows it to be tested as the second emergency shut-off valve, allowing the second valve to close completely without shutting down the process. The use of the two emergency shut-off valves in series wherein either valve can shut down the process provides a level 3 safety integrity level.

1 . A partial stroke testing system coupled with fuel control valve, comprising:
 a combustion gas delivery line;   a selectively operable gas shutoff valve disposed along the combustion gas delivery line;   a selectively operable combination gas control and shutoff valve disposed along the combustion gas delivery line, the combination gas control and shutoff valve being disposed in series with the gas shutoff valve;   a control system for selectively automatically or manually substantially completely closing and reopening the gas shutoff valve;   a control system for selectively automatically or manually partially closing and opening the gas shutoff valve; and   a control system for selectively automatically or manually substantially completely closing and reopening the combination gas control and shutoff valve.   
     
     
         2 . The partial stroke testing system according to  claim 1 , further comprising:
 a gas vent line extending from the gas delivery line and between the gas shutoff valve and the combination gas control and shutoff valve, the gas vent line having a distal end; and   a gas combustion port disposed at the distal end of the gas vent line.   
     
     
         3 . The partial stroke testing system according to  claim 1 , further comprising:
 a combustion gas bypass line disposed in parallel about the combination gas control and shutoff valve; and   at least one selectively openable and closable bypass line shutoff valve disposed along the combustion gas bypass line.   
     
     
         4 . The partial stroke testing system according to  claim 1 , further comprising:
 a gas shutoff valve actuator communicating pneumatically with the gas shutoff valve;   a pneumatic pressure line communicating pneumatically with the gas shutoff valve actuator;   a main solenoid valve disposed in the pneumatic pressure line, the main solenoid valve selectively controlling pneumatic pressure to the gas shutoff valve actuator;   a pneumatic vent line communicating pneumatically with the pneumatic pressure line;   a second solenoid valve disposed in the pneumatic vent line, the second solenoid valve selectively controlling pneumatic pressure in the pneumatic vent line;   a combination gas control and shutoff valve actuator communicating with the combination gas control and shutoff valve; and   a third solenoid valve communicating pneumatically with the combination gas control and shutoff valve actuator;   wherein closure of any one of the main solenoid valve, second solenoid valve, and third solenoid valve results in closure of one of the gas shutoff valve and combination gas control and shutoff valve.   
     
     
         5 . The partial stroke testing system according to  claim 4 , further comprising:
 an emergency shut-off system controller communicating electronically with the main solenoid valve, the second solenoid valve, and the third solenoid valve;   a computer communicating electronically with the emergency shut-off system controller; and   a process control communicating pneumatically with the combination gas control and shutoff valve actuator.   
     
     
         6 . The partial stroke testing system according to  claim 4 , further comprising a current to pressure converter communicating pneumatically with the combination gas control and shutoff valve actuator. 
     
     
         7 . The partial stroke testing system according to  claim 4 , further comprising:
 a first open limit switch, a first closure limit switch, and a partial stroke limit switch, each of the switches communicating with the gas shutoff valve and the emergency shut-off system controller; and   a second open limit switch and a second closure limit switch, each of the second limit switches communicating with the combination gas control and shutoff valve and the emergency shut-off system controller.   
     
     
         8 . A partial stroke testing system coupled with fuel control valve, comprising:
 a combustion gas delivery line;   a selectively operable gas shutoff valve disposed along the combustion gas delivery line;   a selectively operable combination gas control and shutoff valve disposed along the combustion gas delivery line, the combination gas control and shutoff valve being disposed in series with the gas shutoff valve;   a control system for selectively automatically or manually substantially completely closing and reopening the gas shutoff valve;   a control system for selectively automatically or manually substantially completely closing and reopening the combination gas control and shutoff valve;   a gas vent line extending from the gas delivery line and between the gas shutoff valve and the combination gas control and shutoff valve, the gas vent line having a distal end; and   a gas combustion port disposed at the distal end of the gas vent line.   
     
     
         9 . The partial stroke testing system according to  claim 8 , further comprising a control system for selectively automatically or manually partially closing and opening the gas shutoff valve. 
     
     
         10 . The partial stroke testing system according to  claim 8 , further comprising:
 a combustion gas bypass line disposed in parallel about the combination gas control and shutoff valve; and   at least one selectively openable and closable bypass line shutoff valve disposed along the combustion gas bypass line.   
     
     
         11 . The partial stroke testing system according to  claim 8 , further comprising:
 a gas shutoff valve actuator communicating pneumatically with the gas shutoff valve;   a pneumatic pressure line communicating pneumatically with the gas shutoff valve actuator;   a main solenoid valve disposed in the pneumatic pressure line, the main solenoid valve selectively controlling pneumatic pressure to the gas shutoff valve actuator;   a pneumatic vent line communicating pneumatically with the pneumatic pressure line;   a second solenoid valve disposed in the pneumatic vent line, the second solenoid valve selectively controlling pneumatic pressure in the pneumatic vent line;   a combination gas control and shutoff valve actuator communicating with the combination gas control and shutoff valve; and   a third solenoid valve communicating pneumatically with the combination gas control and shutoff valve actuator;   wherein closure of any one of the main solenoid valve, second solenoid valve, and third solenoid valve results in closure of one of the gas shutoff valve and combination gas control and shutoff valve.   
     
     
         12 . The partial stroke testing system according to  claim 11 , further comprising:
 an emergency shut-off system controller communicating electronically with the main solenoid valve, the second solenoid valve, and the third solenoid valve;   a computer communicating electronically with the emergency shut-off system controller; and   a process control communicating pneumatically with the combination gas control and shutoff valve actuator.   
     
     
         13 . The partial stroke testing system according to  claim 11 , further comprising a current to pressure converter communicating pneumatically with the combination gas control and shutoff valve actuator. 
     
     
         14 . The partial stroke testing system according to  claim 11 , further comprising:
 a first open limit switch, a first closure limit switch, and a partial stroke limit switch, each of the switches communicating with the gas shutoff valve and the emergency shut-off system controller; and   a second open limit switch and a second closure limit switch, each of the second switches communicating with the combination gas control and shutoff valve and the emergency shut-off system controller.   
     
     
         15 . A partial stroke testing system coupled with fuel control valve, comprising:
 a combustion gas delivery line;   a selectively operable gas shutoff valve disposed along the combustion gas delivery line;   a selectively operable combination gas control and shutoff valve disposed along the combustion gas delivery line, the combination gas control and shutoff valve being disposed in series with the gas shutoff valve;   a control system for selectively automatically or manually substantially completely closing and reopening the gas shutoff valve;   a control system for selectively automatically or manually substantially completely closing and reopening the combination gas control and shutoff valve;   a combustion gas bypass line disposed in parallel about the combination gas control and shutoff valve; and   at least one selectively openable and closable bypass line shutoff valve disposed along the combustion gas bypass line.   
     
     
         16 . The partial stroke testing system according to  claim 15 , further comprising a control system for selectively automatically or manually partially closing and opening the gas shutoff valve. 
     
     
         17 . The partial stroke testing system according to  claim 15 , further comprising:
 a gas vent line extending from the gas delivery line and between the gas shutoff valve and the combination gas control and shutoff valve, the gas vent line having a distal end; and   a gas combustion port disposed at the distal end of the gas vent line.   
     
     
         18 . The partial stroke testing system according to  claim 15 , further comprising:
 a gas shutoff valve actuator communicating pneumatically with the gas shutoff valve;   a pneumatic pressure line communicating pneumatically with the gas shutoff valve actuator;   a main solenoid valve disposed in the pneumatic pressure line, the main solenoid valve selectively controlling pneumatic pressure to the gas shutoff valve actuator;   a pneumatic vent line communicating pneumatically with the pneumatic pressure line;   a second solenoid valve disposed in the pneumatic vent line, the second solenoid valve selectively controlling pneumatic pressure in the pneumatic vent line;   a combination gas control and shutoff valve actuator communicating with the combination gas control and shutoff valve; and   a third solenoid valve communicating pneumatically with the combination gas control and shutoff valve actuator;   wherein closure of any one of the main solenoid valve, second solenoid valve, and third solenoid valve results in closure of one of the gas shutoff valve and combination gas control and shutoff valve.   
     
     
         19 . The partial stroke testing system according to  claim 18 , further comprising:
 an emergency shut-off system controller communicating electronically with the main solenoid valve, the second solenoid valve, and the third solenoid valve;   a computer communicating electronically with the emergency shut-off system controller;   a process control communicating pneumatically with the combination gas control and shutoff valve actuator; and   a current-to-pressure converter communicating pneumatically with the combination gas control and shutoff valve actuator.   
     
     
         20 . The partial stroke testing system according to  claim 18 , further comprising:
 a first open limit switch, a first closure limit switch, and a partial stroke limit switch, each of the switches communicating with the gas shutoff valve and the emergency shut-off system controller; and   a second open limit switch and a second closure limit switch, each of the second switches communicating with the combination gas control and shutoff valve and the emergency shut-off system controller.