I. Overview 

 900X Emergency shutdown valve is from the main valve, needle valve, pilot valve, pressure gauges and other pipe fittings formed to take over. Is used for fire water and domestic water supply system in parallel, to the direction of deployment of water supply valve. When a fire occurs, large quantity of water needed for fire, 900X emergency shut-off valve immediately cut off the water to ensure adequate fire water; When the fire stopped when the water pressure decreases, the valve automatically opens, showing a normally open state, restore domestic water supply. The working principle is that when the main valve inlet pressure below the set pressure of pilot valve, pilot valve is turned on at this time, the main valve cover chamber pressure and the main valve outlet pressure equal to, import and export existing pressure, flow through export out of the valve port. When the fire pump the action, or pump pressure increases, more than the set pressure the pilot valve, through the wizard from the main valve inlet valve control pipe pressure increases, the role of pressure on the spring, pressed down and drives the valve pin down, so the pilot valve closed, when the main valve inlet pressure through the throttle constantly added to the main valve cover chamber, the valve flap downward because of the pressure is greater than the upward thrust, the main valve is closed. It is noteworthy that the inlet pressure is less than the set pressure of the valve has been turned on, the inlet pressure greater than the set pressure, the valve is turned off. The valve makes the system without a separate dedicated fire a single water supply network, greatly save construction costs and water consumption. The valve control sensitivity, safety and reliability, debugging a simple, long life, for living quarters in the fire water and domestic water supply system in parallel. The main valve part material as follows: 

 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 

 Nominal diameter size (mm) 
 (Mm) L H1 H 
 20150247342 
 25160247342 
 32180247342 
 40200277342 
 50203277342 
 65216278405 
 80241313430 
 100270350510 
 125300365560 
 150330420585 
 200400450675 
 250480470730 
 300550490760 
 350622526840 
 400685570910 
 450750570910