It is used to maintain the upstream water supply pressure of the main valve as a fixed value. When the upstream water pressure is greater than the set water pressure, the main valve opens quickly to relieve pressure. When the pressure is lower than the set pressure, the main valve is closed to hold the pressure.

 

The valve is composed of main valve and external control components. The main valve is composed of valve body, valve stem, valve plate, valve cover, valve seat, piston, piston cylinder and adjusting screw. The external control parts are mainly composed of pilot valve, regulating valve and manual ball valve.

 

① Before operation, the main valve will close naturally under the action of disc gravity, and the pilot valve will close under the action of spring force. The inlet control valve has been set to a certain opening when leaving the factory. At the beginning of operation, the medium enters the inlet end and flows to the lower part of the main valve disc. At the same time, some medium enters the upper part of the diaphragm (piston) of the control chamber after regulating the flow through the connecting pipe through the regulating valve. In addition, some water directly enters the pilot valve port D through the connecting pipe. In this way, there is pressure medium at m, and the valve core of pilot valve is affected by four forces: gravity, downward water pressure at m, elastic force of spring and water pressure at e and F. the resultant force of these four forces is downward to close the pilot valve. The main valve disc remains closed and the system maintains pressure.

 

② Pressure relief: with the increase of the pressure at the inlet end of the main valve, the pressure of chamber e of the pilot valve increases. When the pressure value reaches the resultant force exerted on the valve core of the pilot valve upward, the pressure medium will push up the valve stem of the pilot valve and connect the port C and port F of the pilot valve. The pressure medium above the diaphragm of the control chamber of the valve rapidly flows into the outlet end of the main valve through port C and port F. the medium pressure of the main valve above the diaphragm (piston) of the control chamber is released. The pressure medium under the main valve disc quickly opens the main valve disc, relieving the excessive pressure at the inlet end of the main valve to ensure the safety of the system.

 

③ When the pressure at the inlet end of the main valve drops below the set value, the spring force of the pilot valve overcomes the medium pressure in M cavity to close the pilot valve. The pressure medium at the inlet end of the main valve slowly enters the control chamber of the main valve after passing through the angle type regulating valve. Therefore, the main valve is slowly closed to maintain the pressure at the inlet end of the main valve and maintain the pressure to reduce the water hammer when closing the valve.

1. 2, 3, 4, 7 ball valve, 5, pilot valve, 6, adjusting bolt

3. Manual pressure relief
In case of emergency, membrane damage and switch failure of the pilot valve, the manual 3 ball valve can be opened to quickly release the pressure medium in the upper chamber of the main valve control chamber, so as to open the main valve and achieve the purpose of rapid pressure relief.

The range of pressure relief and pressure holding is large.
Full channel valve body has large flow rate and quick pressure relief. Slow closing speed can be adjusted to eliminate water hammer. High safety and reliability.
It has automatic water pressure control system and manual pressure relief device.
Convenient adjustment and maintenance.
Applicable medium: water or liquid with physical and chemical properties similar to water.
Medium temperature: 0 ℃ - 9 ℃.