D-PRSV SERIES - PRESSURE REDUCING AND SUSTAINING CONTROL VALVE

PRODUCT DESCRIPTION

Pressure reducing and sustaining control valves are automatic control valves which are used in pumping facilities where water is transferred to a lower level. Pressure reducing and sustaining pilot valve on the main valve is used simultaneously. Pressure sustaining pilot valve enables the pump to start operation smoothly. At the moment when the pump is started, main valve is in closed position. Having opened the main valve slowly, pressure sustaing valve transfer the water to the system. Thus, pressure fluctuation in the system is prevented. As for the pressure reducing valve, it is used to decrease the excessive pressure which may be exerted on the transfer pipes and water armatures in the lower level.

PROPERTIES

1- Pressure sustaining hydraulic control valves could easily be used in horizontal or vertical positions in the application systems.
2- Continuously measures the pressure at the inlet and outlet of the valve and keeps it constant.
3- When used at the pump outlets in the horizontal or deep-well pumping facilities, it enables the pump to start smoothly and economizes electrical energy consumption.
4- Operates hydraulically only with line pressure without requiring any extra power supply.
5- Since design of the valve is with diaphragm actuator, its maintenance is easy and cheap, as well.

WORKING PRINCIPLE

VALVE OPEN
When the pump pressure increases, spring force in the 2 way pressure sustaining pilot valve is overcome and discharge port of the pilot valve opens. Pressurized water in the actuator of the main valve is discharged through the discharge port of pressure sustaining pilot valve to atmosphere and thus, main valve switches to open position.

VALVE CLOSED
When the pump pressure decreases, spring force in the pilot valve pushes the piston which is connected to diaphragm of pilot valve and closes the discharge port. Line pressure at the normal level enables the actuator of the main valve to be filled up with the pressurized water from the the inside of the pilot valve. Hence, pressurized water in the actuator pushes the diaphragm with the help of valve’s spring force and switches the valve to closed position with a full-sealing.

MODULATION MODE
Pressure sustaining pilot valve is adjusted according to the pump pressure value. As the pump pressure value increases, discharge port of the pressure sustaining pilot valve opens and pressurized water is transferred to the pressure sustaining pilot valve. Owing to that pilot valve, valve outlet pressure value could be adjusted to the desired value. Having beeen measured continuously by means of pilot valves, valve inlet and outlet pressures are kept within the desired range in the modulation mode.

SAMPLE MOUNTING AND APPLICATION SCHEME

1) Pump
2) Isolation Valve (Gate Valve, Butterfly Valve, etc.)
3) Strainer Valve
4) Pressure Reducing and Sustaining Control Valve
5) Manometer
6) Air Discharge Valve (Vacuum Lifter)
7) Check Valve

APPLICATION SCHEME

- Install the valve according to the flow direction arrow on it.
- For the sake of simplicity in case of service maintenance, it is recommended to mount isolation valves (gate, butterfly or ball etc. valves) to close the water in the inlet direction of the line.
- For enabling the valve to operate efficiently, it is recommended a vacum lifter to be placed before the valve.
- To avoid frosting in the winter, discharge the water in the valve actuator into atmosphere.
- Pressure adjustment of pilot valves could be done by means of adjustment bolt shown as 6. Turning adjustment bolt clockwise will increase the pressure while it decreases when turned counterclockwise.
- Valve inlet pressure value is adjusted via pressure sustaining pilot valve shown as 4.
- Valve outlet pressure value is adjusted via pressure reducing pilot valve shown as 5.
- Clean the filter of the strainer shown as 2 periodically according to the contamination level of water.

1) Mini Ball Valve
2) Strainer
3) Manometer
4) Pressure Sustaining Pilot Valve
5) Pressure Reducing Pilot Valve
6) Pilot Adjustment Bolt