An emergency shut-off valve is a type of hydraulic control valve. It consists of a main valve, a throttle valve, a pilot valve, a pressure gauge, and other pipe fittings. When the inlet pressure of the main valve is lower than the set pressure of the pilot valve, the pilot valve is open. The pressure inside the main valve's upper cover chamber is equal to the main valve's outlet pressure, creating a pressure difference between the inlet and outlet. Water flows through the valve port and out of the outlet. When the fire pump starts, or the pressure of the variable frequency pump rises and exceeds the set pressure of the pilot valve, the pressure through the pilot valve control pipe increases from the main valve inlet. This increases the pressure acting on the spring, pressing it downwards and causing the valve core to move downwards, closing the pilot valve. At this time, the main valve inlet pressure continuously replenishes the upper chamber of the main valve's valve cover through the throttle valve. Because the downward pressure on the valve disc is greater than the upward thrust, the main valve closes. The key point to note is that when the inlet pressure is less than the set pressure, the valve remains open; when the inlet pressure is greater than the set pressure, the valve is closed.
This valve is suitable for water supply systems in residential communities where fire-fighting water and domestic water are connected in parallel. When fire-fighting water is needed, the valve automatically shuts off the domestic water supply to ensure fire-fighting water supply. When the firefighting is over, the valve automatically opens to restore domestic water supply, which is more cost-effective than traditional separate firefighting water supply.
Functions
Emergency Shutdown Function:
During firefighting operations, the system pressure rises, and the valve automatically shuts off the domestic water supply, ensuring sufficient firefighting water supply.
After the firefighting operation ends, the system pressure drops, and the valve automatically opens, restoring the domestic water supply.
Safety Assurance:
Prevents competition between firefighting and domestic water supply, ensuring the reliability of the fire protection system.
Prevents backflow of firefighting water from contaminating domestic water supply (requires a backflow preventer).
Cost Optimization:
No separate firefighting water supply network is required, reducing construction costs and maintenance complexity.
Selection Guide
Nominal Diameter (DN):
Standard models: DN40～500mm, covering the needs of most residential communities.
Special Requirements: Customized large-diameter valves from DN350～700mm are available.
Nominal Pressure (PN):
Standard pressure ratings: PN1.0, PN1.6, PN2.5MPa, adaptable to different water pressure scenarios.
Media and Temperature:
Applicable Media: Clean water, sewage, seawater, and other non-corrosive liquids. Temperature range: ≤80℃. Special materials are required for high-temperature applications.
Connection method:
Primarily flange connection for easy installation and maintenance.
Emergency Shut off Valve Factory
