AREA OF APPLICATIONS
The N.G.D shock prevention valve prevents the occurrence of water hammer when: –
- The entire pump station trips.
- The last of the running pumps trips.
- A pump operator abruptly switches the last running pump.
The N.G.D shock prevention system is a unique solution for high-pressure vertical or inclined pumpingsystems. The N.G.D valve can open instantaneously to prevent the water hammer occurrence.
The N.G.D shock prevention valve is used as the column drain valve, enabling a cavitation-free draining of the pump discharge column.
PRINCIPLE OF OPERATION
The N.G.D shock prevention valve instantaneously opens on pump’s trip occurrence, to enable a flow passage to the station’s reservoir and as a result to avoid abrupt stoppage of the reversing flow, with no need for actuators, pilots, sophisticated instruments or an external power source.
THE CONTROL SYSTEM
The control system consists of a: –
- N/O timer switch closes on pump’s trip occurrence and reopens after a short interval.
- N/C Solenoid valve, causing the instantaneous opening of the shock prevention valve when the timer switch closes.
- The N/C solenoid valve closes after a short time interval and fluid entering slowly to the valve’s closing compartment causes the slow closing of the shock prevention valve.