Pressure control system for relief and shutdown of flow

Abstract

This disclosure is related to a non-electronic pressure control system for a pressurized system that receives fluid from a fluid supply. The pressure control system includes a control module, an actuator and a flow control device. The control module monitors the pressure of fluid either upstream or downstream of the flow control device. The control module can send a pneumatic signal to the actuator to open or close the flow control device responsive to the pressure monitored by the control module and the pressure required for the pressurized system.

What is claimed is: 
     
         1 . A pressure control system for monitoring fluid pressure for a pressurized system, the pressure control system comprising:
 a fluid control device for affecting the pressure of fluid downstream from the fluid control device;   an actuator for opening and closing the fluid control device; and   a control module for processing pneumatic signals from at least one predetermined pressure point upstream or downstream from the fluid control device, the control module sending signals to the actuator to open or close the fluid control device responsive to pneumatic signals, the control module comprising:
 a pressure sensor to determine pressures of the fluid from the at least one predetermined pressure point; 
 an air switch to receive pneumatic signals from the pressure sensor responsive to the pressure of the fluid from the at least one predetermined pressure point; and 
 a charge valve to send a pneumatic signal to the actuator or exhaust fluid from the control module responsive to a pneumatic signal received from the air switch. 
   
     
     
         2 . The pressure control system of  claim 1  further comprising a fluid supply which provides a fluid source for the pressurized system, the fluid supply in fluid communication with the pressurized system via a fluid transportation conduit. 
     
     
         3 . The pressure control system of  claim 1  wherein the predetermined pressure point can be located upstream or downstream of the fluid control device. 
     
     
         4 . The pressure control system of  claim 1  wherein the predetermined pressure point can be located within the pressurized system. 
     
     
         5 . The pressure control system of  claim 1  wherein fluid is taken from the predetermined pressure point to the control module via a first pressure sensing line. 
     
     
         6 . The pressure control system of  claim 1  wherein the control module further comprises a first regulator to control the pressure of fluid entering the control module from an instrument air pressure line and passing to the charge valve. 
     
     
         7 . The pressure control system of  claim 1  wherein the control module further comprises a circuit enable to stabilize and optimize performance of the air switch. 
     
     
         8 . The pressure control system of  claim 1  wherein the control module opens or closes the fluid control device via the actuator when the pressure of the fluid from the predetermined pressure point is above or below a predetermined pressure range. 
     
     
         9 . The pressure control system of  claim 1  wherein the control module opens or closes the fluid control device via the actuator when the pressure of the fluid from the predetermined pressure point is above or below a predetermined pressure. 
     
     
         10 . The pressure control system of  claim 1  wherein the predetermined pressure point is positioned upstream from the fluid control device and a second predetermined pressure point is positioned downstream of the fluid control device. 
     
     
         11 . The pressure control system of  claim 10  wherein the predetermined pressure point is positioned upstream from the fluid control device and the second predetermined pressure point is positioned at a location within the pressurized system. 
     
     
         12 . The pressure control system of  claim 10  wherein the fluid from the second predetermined pressure point is fed to the pressure sensor of the control module in addition to the predetermined pressure point. 
     
     
         13 . The pressure control system of  claim 12  wherein the pressure sensor provides a pneumatic signal to the air switch responsive to the differential in pressure between the fluid from the pressure of the fluid from the predetermined pressure point and the fluid from the second predetermined pressure point.