Valve ΑS-A/Y-40 is installed at the outlet of the pump to absorb the surge waves caused when the pump stops or starts. In that way it protects the pump from being damaged.
The valve opens and closes while the pump works and prevents the back flow in case of power failure.

In combitation with pressure relief valves AS-A/Y-30 or AS-A/Y-35 it provides smooth working conditions, especially when there are changes of the flow rate of the pump, because valve AS-A/Y-40 maintains a constant flow and pressure with great accuracy at a pre-set point.