Pressure and vacuum relief valves
With the help of pressure and vacuum relief valves, it is possible to avoid the emergence of under pressure (vacuum) in the piping or the tank or the formation of excessive overpressure in the system.
Vacuum gives rise to state of disturbance
A vacuum can occur in oversized heat exchangers – for example, in cases where the steam condenses rapidly and a possibly oversized control valve drives itself into the closed position. If the natural differential pressure in the system becomes negative, it is subjected to water hammer when the condensate drainage stops. We recommend equipment components dimensioned correctly for the application, but on a case-by-case basis, vacuum protection can solve the problem under such circumstances.
The valves by GESTRA, NIEZGODKA, and AWH are designed for relatively small size classes and flow rates. The section Vent valves for tanks includes corresponding pressure and vacuum relief valves for gas, but their set pressures are clearly lower than those of the valves described on this page.
On request, we also offer tailored vacuum relief valves for higher capacities.
Pressure and vacuum relief valves are spring-loaded and open if the set pressure is exceeded. Depending somewhat on the product range and desired flow rates, wedge solutions of different sizes can be added to the valves in order to increase their capacity.
A slight exception is the GESTRA RK 86A non-return valve, which can also be used as a vacuum relief valve owing to its excellent tightness.