Keeping a certain pressure limit is essential for the safety and efficiency of a plumbing system. The use of a plumbing pressure relief valve is important, since it is an essential component to achieve the set pressure.

Primarily, pressure relief valves are utilized to control or limit the overpressure within a system. Due to differing factors, overpressure is created within the system’s pipeline, the overpressure can cause rigorous damage to the system, property and even human life.

With the pressure relief valve’s application, the pre-determined appropriate valve is maintained instead of overpressure. Therefore, ensuring an overall safety, that is why, pressure relief valves are noted among safety valves as well.

But how does a pressure relief valve actually work? To learn more about its working mechanism, keep reading till the end.

Pressure Relief Valve – Working Mechanism

There are essentially three functional elements in a pressure relief valve that constitutes its overall working mechanism. These three elements are:

   i.          Valve element – Commonly a spring-loaded poppet valve.

   ii.          Reference force element – Generally, a spring.

   iii.          Sensing element – Commonly a piston or diaphragm.

The pressure relief valve typically remains closed until the upstream pressure reaches the predetermined pressure. As soon as the chosen pressure reaches, the valve cracks open and it opens up continuously enabling more and more flow as the overpressure increases.

Only when the upstream pressure declines for a few psi below the predetermined pressure then the valve shuts off and closes.

Valve Element               

Typically, in a pressure relief valve, there’s a spring-loaded poppet valve which has an elastomeric seal. In case of high-pressure design pressure relief valves, there's a thermoplastic seal.

This seal is constructed to make a valve seat’s seal. When in operation, the valve element of a pressure relief valve is forced by the upstream pressure and the spring.

When the upstream pressure’s force expends the force of spring, then the poppet moves away from the valve seat that enables fluid flow to get past the outlet port. The valve closes up only when the upstream pressure drops.

Reference Force Element

This is typically a mechanical spring and its function is to exert pressure on the sensing element. This element is used for the closing of the valve

A majority of pressure relief valves have an adjustable design that allows the operator to make an adjustment of the set-point relief pressure by altering the reference spring’s exerted force.

Sensing Element

Sensing element normally consists of a piston or a diaphragm. When high relief pressure is needed, the piston shaped design is effectively used. Piston design is also applied when there’s no requirement for high tolerance held by the relief pressure.

Diaphragm design is applied when there’s requirement for high accuracy or for low pressure applications. The diaphragm has a disc-shaped element that quickly senses the pressure change.

All of these three elements synchronize simultaneously and an efficient working mechanism is carried out. Pressure relief valves play a huge part in keeping water flow controlled within a system.

     Make sure to pick high-quality pressure relief valves to ensure maximum safety in your plumbing system.