The SAMSON Vacuum Limiter Valve is designed to control the pressure (vacuum) level and to avoid cavitation in the pump. The Vacuum Limiter Valve is installed when the suction line may force the pump to operate below the cavitation limit. Air must then be supplied to the suction side of the pump through the vacuum limiter which is regulated according to the required pressure. Cavitation arises when the pressure in the pump falls to under the steam pressure for the service liquid, which makes the liquid boiling and steam bubbles arise in the service liquid. Continuous operation will cause great mechanical damage.