I. Overview: 

 500X pressure relief valve holding pressure from the main valve, pilot valve, needle valve, ball valve, micro-shaped filter and pressure gauge hydraulic control over the system. Use of hydraulic automatic operation, which can be used for pressure relief valve can be used for holding pressure valve. When do pressure relief valve can be set to maintain water pressure in the road safety value below the main valve to maintain the upstream water pressure. It works, adjust the pressure relief valve when the conductivity state, the water through the valve, main valve control room, ball A, pilot valve, ball valve exit flow B, when the main valve is open. When the pilot valve inlet pressure exceeds the set safety value, pressure relief valve will automatically open the guide, through valve C to release some water, so that the pressure relief pipe. When the pressure to a safe value, the pressure relief valve closes automatically. As a pressure relief valve, the valve is always open. When the pilot valve was adjusted to maintain pressure state, as long as the main valve inlet end of the pilot valve pressure setting, pilot valve is closed. The main control room boost, the main valve is closed. When the main valve upstream water pressure exceeds the pilot valve to the exit row, the control room to open the main valve pressure began to water, that is, to maintain the upstream water pressure. For holding pressure valve, the valve C wire blocking the normally closed or replaced. The products use hydraulic self-control, no other devices and energy, maintenance is simple, a multi-purpose valve. Widely used in high-rise buildings, living quarters and other water supply system and urban water supply project. The main valve part material such as a small table: 

 Part Name Material 
 Body, bonnet cast iron, cast steel, stainless steel 
 Bronze seat, stainless steel 
 Valve carbon steel, stainless steel + nitrile rubber 
 Qinggang aluminum stem, chrome stainless steel 
 Nitrile rubber diaphragm 
 Diaphragm plate carbon steel, stainless steel 
 Stainless steel spring 


 Second, the main dimensions: