In each circuit that requires the use of high pressure water, a discharge valve must be installed in addition to the by-pass valve. In case of malfunction of the by-pass valve dangerous pressure peaks can occur that can damage the system or worse, jeopardize the safety of the operator. The pressure relief valve must be calibrated at a pressure 10% -20% higher than the working pressure and obviously must be proportionate to the performance of the system. A pressure relief valve that is too small could in fact discharge too slowly compromising its function as a safety device.
For the selection of the correct valve it is necessary to take into consideration:
PRESSURE AND FLOW RATE
The pressure relief valve must be proportionate to the operating parameters of the system and must intervene at a pressure of about 10% -20% higher than the working pressure. It is thus clear that, if the system works at 200 bar, the drain valve to be used must be able to withstand a pressure of, at least, 240 bar.
TEMPERATURE
As for the by-pass valves, in addition to the flow rate and pressure, it is essential to dwell on the working temperature. There are specially designed exhaust valves for working at high temperatures.
CONSTRUCTION MATERIALS
Finally it is essential to take construction materials into consideration. Brass and stainless steel represent the construction materials with which the bodies and internal components of the pressure relief valves offered by Emiltec are made. Aisi 316 stainless steel is indispensable when working with salt water, demineralised water or more generally with solutions that involve mixing water with aggressive substances.