Pressure Reducing Systems

PRS/Gas trains are consisting of,

Ball valves: to isolate the system from main supply or to isolate the either side of PRS.

Filtration unit: A filter protects rest of the system from any debris or dust that may carried with gas stream. Debris may for example consist of parts accidently left in the pipe during construction. It could also result from swarf from drilling holes & taps or welding & sand from construction or fine iron oxide dust.

Slam shut off Valve: Slam shut off valves is installed after Filter & before pressure regulator. Slam shut off valve close the supply of gas when a downstream pressure exceeds a pre-determined limit.

Pressure regulator: Pressure regulator maintain downstream pressure at certain quantity of gas , irrespective of variation in upstream pressure from maximum to minimum limit. Spring loaded or Pilot operated pressure regulators are used.

Relief valves:

• Creep relief Valve: A slight weeping of pressure regulator/ increase in downstream due to rise in downstream surrounding temperature result in increasing the downstream pressure to dangerous level, such creep pressure is blown off through creep relief valve.
• Safety Relief Valve: The safety relief valve set at higher pressure than slam shut off valve so that the safety relief valve will operate when slam shut off valve fails to operate.