Product Introduction

This product is designed and manufactured by our factory's engineering and technical personnel with reference to advanced products of the same type from the United States, France and other countries. It is suitable for parallel water supply systems in industrial enterprises, domestic water supply and fire water supply. During fire water supply, the valve automatically closes urgently to cut off domestic water supply and ensure fire water demand. After the fire is extinguished, the valve automatically opens to resume domestic water supply. It can replace the intermediate water tank in occasions requiring static pressure and dynamic pressure reduction, saving the cost of building intermediate water tanks and expanding the usable space of buildings. The valve body adopts a full-channel streamlined design, featuring low fluid resistance and large flow rate. Hydraulic operation is adopted for the transmission method—utilizing the water pressure in the pipeline to automatically drive the main valve disc up and down, control the valve port opening, adjust the downstream pressure, and maintain the downstream pressure at the set value of the pilot valve spring. When the downstream pressure exceeds the set value, the pressure reducing valve will automatically close. Regardless of fluctuations in the inlet pressure P1, a stable outlet pressure P2 can be output. It can adapt to downstream flow changes ranging from 10% to 80% of the inlet pressure, operating stably without water hammer impact.

900X Piston Type Emergency Shut-off and Pressure Reducing Valve Product Diagram

Working Principle

When fire water is used, open Ball Valve 19 and close Ball Valve 6 (see the structural diagram). Under the action of reverse pressure, when the pressure below the diaphragm of the pilot valve exceeds the spring setting value above the pilot valve, the pilot valve closes. Due to the function of the check valve, the water discharge volume in the control chamber is 0, and the main valve will automatically close to cut off domestic water supply and ensure fire water supply. When the fire fighting is completed, close Ball Valve 19 and open Ball Valve 6, the valve will automatically open to resume domestic water supply. Inlet pressure P1 enters the control chamber of the main valve through the conduit and needle valve, and establishes downward pressure P3. Outlet pressure P2 also acts under the diaphragm (or piston) of the pilot valve through the conduit and opposes the regulating spring of the pilot valve. When the variable pressure P3 reaches the maximum value, the main valve disc is pressed tightly against the valve seat and the pressure reducing valve closes. Once the downstream pressure P2 drops to the pilot valve spring setting value, the pilot valve opens, and the pressure water in the control chamber will be discharged to the downstream through Pilot Valve 9 and Ball Valve 6. Due to the small opening of the needle valve and the smaller diameter of the inlet conduit than the outlet conduit, the discharge speed is greater than the inlet pressure water supplement speed, thus the pressure P3 in the control chamber decreases. The inlet pressure P1 acting under the main valve disc will lift the main valve disc, thereby opening the pressure reducing valve. In the stable regulation state, the discharge flow is equal to the water supplement flow, the opening of the main valve port remains unchanged, and the downstream pressure is stable. (This is the working principle of the diaphragm type, and the piston type is the same.)