800X pressure bypass valve from the main valve, pressure control pilot valve, needle valve, ball valve, micro-shaped filter and pressure gauge hydraulic control over the system. Pilot valve through the specially designed control room, compared to the pressure signal, the output signal the main valve opening to control the main valve opening, the main valve to control the pressure difference at that setting. The working principle is that when the main valve pressure difference between the import and export changes, take over the pressure between A and B change over, the alternating valve opening. Pressure pilot valve to open large degree, the control room of water discharged through the C tube increases, the main valve pressure drop in the control room, the main valve opening increases, the main valve pressure difference between the import and export smaller. Conversely, if the main valve pressure difference between the import and export smaller, the pilot valve open for smaller, the main valve control room pressure rise, decreased drive leaving the main valve opening the main valve pressure increases. This negative feedback to stabilize the main valve pressure difference between the import and export value in the community on top. Set the needle valve opening and valve spring pressure can be set to guide the main valve pressure differential between the import and export. The products use hydraulic self-control, no other devices and energy, maintenance is simple, widely used in high-rise buildings, living quarters and other water supply system and urban water supply project, to be part material as follows: 

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


 Second, the main dimensions: 

 Nominal diameter D1 D2 N-φD LH 
 1.0MPa 1.6MPa 1.0MPa 1.6MPa 1.0MPa 1.6MPa 
 DN50 165 125 4 - 19 203 160 
 DN65 185 145 4 - 19 215 180 
 DN80 200 160 8-19 241 200 
 DNl00 220 180 8-19 270 270 
 DNl25 250 210 8 -19 292 310 
 DNl50 285 240 8-23 330 320 
 DN200 340 295 8-23 12-23 400 370 
 DN250 405 350 355 12-23 12-19 
 <, / TD> 480 430 
 N300 460 400 410 12-23 12-28 550 480 
 DN350 520 460 470 16-28 16-28 622 525 
 DN400 580 515 525 16-28 16-31 685 580 
 DN450 640 565 585 20-28 20-31 750 635 
 N500 715 6