Swing check valves and the importance of temperature when designing

In addition to the temperature pressure diagram, the load loss diagram is also required to choose swing check valves correctly

The main job of the stainless steel swing check valves in the INTERTUBI catalogue is to operate the fluid seal inside the system. The flap, in fact, closes through gravity when the flow inside the piping is interrupted.
This is why swing check valves have to be fitted horizontally if possible, or at an angle that allows the flap, which does not have a spring, to fall.
This is known technology. Instead, one of the design aspects evaluated when swing check valves are used is mechanical resistance at high temperatures. This is done by consulting the pressure-temperature diagram. The catalogue, in fact, gives the maximum working pressure, but it refers to a temperature range which reaches up to approximately 40° C for this type of valve. From this point to the maximum working temperature, the maximum working pressure decreases in an almost linear manner until it almost zeroes.
For swing check valves, this diagram is just as important as that of the load losses.