Pressure Relief Valves

Materials Used

Types

Uses

The pressure relief valves are a kind of safety valve, used widely in various industrial applications. They are self-actuated valves manufactured to relieve excess pressure upstream from the line. They are designed in such a way so as to provide protection from over-pressure in steam, gas, air and liquid lines. The pressure relief valve "lets off steam" when safe pressure exceeds, and close automatically when pressure drops to a preset level. The main purpose of pressure relief valve is to provide protection from over-pressure in steam, air, gas and other liquid lines.

Buying Tips Never select a pressure relief valve for your application based on just the size of the pipe in the system or the set pressure. If you do this way, you are almost guaranteed to be spending time trying to find out why the valve is not doing what it is supposed to do. The first thing to decide is the type of pressure relief valve. Examine all the application parameters before reaching a decision on a pressure relief valve. Factors to consider are as follows: Material End Connection End Usage Sizes Inlet pressure Operating differential pressure Durability Corrosion resistant

Materials used:

• Brass
• Bronze
• Steel
• Copper
• Cast Iron
• Cast Steel
• Stainless Steel
• Zirconium
• Rubber
• Plastic etc.

Types of pressure relief valves:

• The safety or pop off valve: This type of valve opens completely when the set pressure is reached. It diverts almost all of the flow out the discharge port of the pressure relief valve. An example of this type of relief valve is found on hot water heaters. This valve protect the heaters from damage if steam form inside the heater and cause over pressurization.
• The other common type of relief valve is the one that gradually diverts the flow out of the discharge port as the pressure is relieved. This type of valve is often used not only to relieve pressure but also to control the flow in the piping system.

Uses of pressure relief valves:

• Pressure relief valves are used whenever there is a need to exhaust the overpressure volume of gas, vapor and/or liquid.
• Pressure relief valves are used to control flow as well as pressure.
• They prevent inlet pressure from rising.
• The unique closure mechanism available in this type of valve maintains complete water shutoff in the fully closed condition.
• The pressure relief valve is clog-resistant.
• These valves are usually excellent in durability and practically maintenance-free. Hence, using this valve is considered to be economical.
• These valves are designed to be used on-
  • oil and gas production systems
  • gas transmission
  • compressor stations
  • pipeline facilities
  • storage systems
  • gas processing plants
  • petrochemical and refinery operations etc.