What is a Pressure Relief Valve?
What is a Pressure Relief Valve?
A pressure relief valve (PRV) is a type of safety-related component used in the pipeline or with vessels in pneumatics. Relief valves are used to limit the amount of compressed air pressure in a system so that it doesn’t build up above a pre-set level and cause damage to machinery or people. These types of valves are therefore used to stop over-pressurisation, where air pressure exceeds the maximum allowed for that system.
Also known as...
A pressure relief valve is also referred to as a PRV, a relief valve, or a pressure release valve.
How do pressure relief valves work?
Relief valves are designed to protect compressed air systems from over-pressurisation by releasing excess pressure.
Pressure acts against the valve seat and the force generated opens the valve against a spring tension. Turning the control knob can increase or decrease the tension in the spring, therefore adjusting the pressure required to open the valve.
Should pressure rise above a pre-determined setting, pressure will be relieved through a spring-loaded mechanism which opens due to the increased pressure upstream of the valve, compared to the set point. Once air has been exhausted out of the system, and the pressure has fallen down to its pre-set level, the pressure relief valve will close.
To stop a tank or vessel from becoming over-pressurised, pressure relief valves can be used to exhaust air into the atmosphere quickly and are an important component in terms of both safety and the reliable running of an air compression system.
How do I select pressure relief valves?
There are a wide variety of pressure relief valves available and choosing the appropriate valve will depend on the type of application you will be using it for. Norgren’s comprehensive range includes valves designed to fit with the Excelon and Olympian Plus ranges, as well as valves for pressure vessels and those with the ability to be utilised in system pipework.
Before selecting your pressure relief valve, you should consider the following:
Operating pressure range / maximum pressure level
Flow requirement for system delivery
Failure mode
What temperatures the valve is required to act at
Where it is utilised in the compressed air system
The port size required
How it will be mounted
Material type required: e.g. brass, steel
Environment to be used in: e.g. corrosive
Types of pressure relief valves
Norgren’s range of pressure relief valves include:
Excelon modular system pressure relief valves
Olympian Plus relief valves
Miniature ported pressure relief valves
Pop Type relief valves
Typical applications of pressure relief valves
Pressure relief valves are commonly seen in any application which uses compressed air, such as pneumatics systems in industrial automation.
They’re also an important component in high pressure applications such as oil and gas and defence and nuclear, where industrial and process gases are stored and transported at high pressure and need to be regulated down to a safe working pressure before use.
Pressure relief valves should always be used where there is a risk to any individual or process from over-pressurisation. It is good practice to automatically include them in any system design.
Do I need anything else to make pressure relief valves work?
Accessories required for use with valves depend on the type selected, and can include wall mountings and gauges. Tubing and fittings will be required to connect the relief valve into a system. Tamper resistant kits are also available on some pressure relief valves.
Visit our Valves section to find out more.