Common Types Of Relief Valves

You should not try and pick right Pressure Relief Valves for the application on the basis of size of pipes in system and for setting the pressure.

The very first thing for determining here is kind of pressure relief valves that you look for. There are 2 common kinds of relief valve. One of pop off or safety valve which opens completely once the fixed pressure reaches, diverting all of flow out discharge port of valve. The example of this kind of relief valve, is made up of metal, is found on the hot water heater for protecting them from damages should steam from inside heater and causes over pressurisation.

Common types of relief valves

Other common kind of relief valve diverts flow out gradually out of discharge port while the pressure relieves. This kind of valve is used not just for relieving pressure but for controlling flow in system.

In this kind of valve, the spring pushes down the piston on the seat. Since pressure exceeds set pressure, piston moves off the seat and flow of pressure gradually gets diverted from discharge port. More flow gets diverted since the pressure of the system continues for increasing above set pressure. When piston pushes far up in the valve which its design allows, the maximum flow reaches. These kind of pressure relief valves are used for controlling the pressure and flow. 

One single application used is to use the pressure relief valve for protecting the pump.