Df41-10 reverse flow preventer

A reverse flow preventer is a hydraulic control assembly that strictly limits the flow of water in a pipe. Its function is to prevent the flow of medium in the pipeline under any working conditions. Aim to avoid reflux pollution.

Backflow machine working principle is to use the medium flows through the check valve when the water resistance and the water head loss due to mechanical and decompression, the inlet pressure is higher than the drain valve chamber pressure, and the upper part of the drain valve diaphragm pressure of inlet pressure, the upper diaphragm pressure is greater than the drain valve chamber and spring resistance, maintain close the drain valve, medium normal flow, when the inlet pressure and drain valve cavity pressure difference is less than 0.02 Mpa, the medium in the back of critical state, then the upper drain valve diaphragm pressure less than the drain valve chamber and the pressure of the spring, the drain valve open automatically. In addition, a large amount of air enters the cavity of the valve, forming an air partition, eliminating the flow of the medium, and the drain valve automatically shuts off when it is greater than 0.02 Mpa.

After valve pipe network pressure raise more than before the valve inlet pressure, such as the second one-way check valve seal well, the water will not flow back, not drain water drain valve closed at this time, when the second one-way check valve leakage of seal failure, the drain valve open drainage pressure relief.

Installation position

The pipe connecting the user with the municipal pipe network is connected to the pipe between the water meter and the valve.

Use the pipe or fire outlet pipe on the fire pump adapter.

There is a chemical injected into the water supply system.

The cold water inlet of the heater may produce a backwater supply line.

Installation instructions

Clean all piping before installation

The backflow preventer is mounted horizontally in the direction of the valve body arrow. Installation location should be convenient for debugging and maintenance

The reverse flow preventer should be installed with the repair gate valve, the preinstallation filter shall be installed, and a flexible connector should be installed at one end

The drain valve shall not be less than 300mm from the ground. The drain valve should have a drainage trench

The installation is finished. For initial start-up use, exit gate valve should be closed, slowly open inlet gate valve and slowly fill the backflow preventer. Open all test ball valves to remove valve air and open the gate valve slowly to fill the pipeline

When pressure changes in the inlet medium, a small leak in the drain valve is normal