|Automatic Recirculation Check Valves (ARC-Valves) are pump protection devices which prevent that the required minimum flow rate will not be dropped below. They protect automatically centrifugal pumps from damage, which might occur through partial evaporation of the fluid content during low load operation and instable flow conditions.
For the main flow - to the process - the valves have an inlet flange DN1 and an outlet flange DN2. The minimum flow is going out through an additional branch DN3 back to the reservoir.
As soon as the pump capacity drops below a predetermined flow rate, the ARC-valve opens sufficiently the bypass to maintain the pump minimum flow rate. This rate is maintained even if the flow in main direction to the boiler or process is completely shut off.
The ARC-valve automatically opens and closes the bypass corresponding to the main flow rate. This flow controlled function operates without additional auxiliary energy.
The pressure and flow reduction to the minimum flow requirements in the bypass line takes place through a multistage throttle system (low cavitations and of low noise).
The integrated non-return valve in the main delivery stream avoids of reverse operation of the pump.