General:
Pressure set on a device (DIN 24 312).
On pressure-limiting and safety valves (DIN 3320):
set pressure p e is the pressureat which in test stand conditions (atmospheric back pressure), directly actuated pressure-limiting valves start to open (Figure E 12) and on pilot-controlled pressure-limiting valves the pilot control starts to initiate the opening of the main stage. It is the response pressure in test stand conditions. In implemented systems the response pressure is at the set pressure.
At the opening pressure p c the full mass flow flows through the valve. The difference between p c and p e essentially depends on the stiffness of the closing spring and is significantly less on pilot-controlled pressure-limiting valves than on directly controlled pressure-limiting valves.
Figure E 12: Set pressure – opening pressure – closing pressure