Wet Alarm Valve: A Core Component of Automatic Sprinkler Systems

What is a Wet Alarm Valve?

A wet alarm valve is a key control component in a wet-pipe automatic sprinkler system. Its main function is to automatically open the water supply channel after the sprinkler head starts spraying water, while simultaneously sending hydraulic and electrical alarm signals to ensure the fire suppression system responds promptly to a fire.

Working Principle: The Wisdom of Water Pressure Balance

The core of a wet alarm valve is a clever differential pressure device.

In standby mode, the water pressure in the upper and lower chambers of the valve remains balanced, but the upper surface area of ​​the valve disc is larger than the lower surface area. Combined with the weight of the valve disc, this keeps the valve closed. When the sprinkler head bursts and sprays water, the pipeline pressure drops, and the pressure below the valve disc is greater than above. This pressure difference pushes the valve disc to open rapidly, opening the main water supply channel.

How the Alarm is Achieved

After the valve opens, a stream of water enters a dedicated alarm pipe. The water flow drives a hydraulic alarm bell to sound an audible alarm, and simultaneously activates a pressure switch, transmitting an electrical signal to the fire control center, automatically starting the fire pump.

Key Technical Parameters

Rated Working Pressure: Typically 1.2MPa or 1.6MPa
Nominal Diameter: Common specifications include DN100, DN150, DN200, etc.
Delay Valve: Prevents false alarms caused by water pressure fluctuations
Test Valve: Used for periodic testing of alarm functionality

Application and Maintenance

Wet alarm valves are widely used in wet systems in high-rise buildings, shopping malls, hotels, factories, and other locations. To ensure reliability, a functional test should be performed monthly using the test valve, and the internal filter should be cleaned and the seals inspected regularly.

As the “nerve center” of an automatic sprinkler fire extinguishing system, the wet alarm valve, with its stable and reliable differential pressure principle, silently safeguards safety, fulfilling its core mission of connecting the water source and issuing an alarm at the critical moment of a fire’s initial outbreak.