What is the Difference Between a Pressure Relief Valve and a Pressure Reducing Valve?
In order to identify and explain the key differences between a pressure relief valve and a pressure reducing valve, how it works must first be understood. Pressure reducing valves simply use spring pressure against a diaphragm to open the valve. The outlet pressure rises and begins to approach the set level. The pressure beneath the diaphragm then starts to overcome spring pressure. As this increases, the stem of the valve is forced upwards and this closes the valve.
Therefore, a pressure relief valve will release extra pressure from the tank or system. Conversely, a pressure reducing valve will diminish the pressure in a pneumatic or hydraulic circuit. Reducing valves are planned to look for even the smallest pressure rises in fluid lines, and they do not permit pressure to increase beyond pre-set limits.
What Causes a Pressure Relief Valve to Open?
Pressure acts against the valve seat and the force generated by this action opens the valve against spring tension. Turning the control knob can increase or decrease the tension in the spring, therefore adjusting the amount of pressure needed to open the valve.
What is the Purpose of a Pressure Regulating Valve?
Pressure regulating valves can be used with either gas or liquid. Essentially, they control the pressure as measured against a pre-set value. These valves can be found in a wide range of applications and are available as either integrated devices or external components.
Pressure regulating valves are designed to operate continuously. This ensures that they can hold a fixed downstream pressure, regardless of the upstream pressure or any fluctuations which might occur.