The utility model relates to a backflow preventer which is a hydraulic control combination device which strictly limits the water in the pipeline to flow only in one direction. The function of the backflow preventer is to prevent the medium from flowing back under any working condition so as to avoid the backflow pollution
The utility model relates to a backflow preventer, which is a hydraulic control combination device which strictly limits the water in the pipeline to flow only in one direction. Its function is to prevent backflow of medium in the pipeline under any working condition. In order to avoid backflow pollution purposes.
Backflow prevention device working principle is to use the medium flow through the inlet check valve for mechanical resistance and head loss of the flow and pressure, the inlet pressure is higher than the discharge valve and the discharge valve cavity pressure, the upper part of the diaphragm pressure to the inlet pressure, outlet pressure is greater than the upper part of the diaphragm valve chamber and the discharge valve spring resistance, maintain the normal flow of closed the medium, when the inlet pressure and outlet valve chamber pressure is less than 0.02Mpa when the medium is in critical state back, then the discharge valve, the upper part of the diaphragm pressure is less than the discharge valve chamber and the pressure of the spring, the discharge valve is automatically opened. The backflow medium is discharged out of the pipe, and a large amount of air enters the valve cavity to form an air separation, and the backflow of the medium is avoided. When the water is larger than 0.02Mpa, the drain valve is automatically closed.
The valve after the water pressure exceeds the water pipe valve forward end pressure, such as the second check valve is sealed, water will not flow back, the discharge valve closed drainage, when the second check valve seal failure caused the leakage, the discharge valve open pressure relief drainage.
Installation location
A diversion pipe connected to a user by a municipal pipe network between the water meter and the valve.
Fire pump adapter into the pipe or outlet pipe on the fire.
In the water supply system, there is a chemical feed into the water pipe.
The cold water inlet pipe of the heater may cause backflow in the water supply pipe.
Installation instructions
1. clean all pipes before installation
2. backflow preventer installed horizontally in the direction of the arrow of the valve body. Installation location should be convenient for debugging and maintenance
3. backflow preventer should be installed at both ends of the maintenance gate valve, imported before the installation of filters, and should be equipped with flexible joints at one end
4. drain valve drain from the ground shall not be less than 300mm. Drain valve should be left under the drainage ditch
5. after installation. For the first time, the gate valve should be closed, and the inlet valve will be opened slowly. The medium shall be slowly and full of backflow preventer. Open each test ball valve, remove the valve air, until the valve cavity is full of water, slowly open the gate valve, let the water fill the pipeline
6. pressure changes in the inlet medium, a small amount of water leakage valve is a normal phenomenon