Dorot model “BC/FR” is an automatic, solenoid controlled valve, activated by the pressure of the pipeline. The valve is installed on the pump discharge.
On start-up of the pump, the valve opens at a slow adjustable pace, until the system flow rate rises to the preset maximum value. The maximum rate of flow is set by a pilot valve, activated by the pressure differential created on an orifice plate, assembled in the main valve inlet flange.
Prior to pump shut-off, the valve slowly closes. This prevents pressure surges that may be caused by a rapid change in velocity.
A limit switch, assembled on the main valve bonnet, is connected to the pump control panel and switches off the motor when the valve has completed closing.
In case of a power or pump failure, the valve instantly closes, performing as a fast-reacting check valve.
The main valve is "normally closed" (N.C.). An electric signal opens the valve.
The standard electric current of the solenoid is 24VAC, 50Hz. Various coils, suitable to other electric currents, are supplied on request.
The main valve is supplied in two models:
- Model 30D for medium pressure (up to 16 bar / 230 psi) Model 31D for high pressure (up to 25 bar / 350 psi).