The core of the fire extinguishing system is all kinds of alarm valves. The following is the related content of wet alarm valve.
1、 Working principle
1) When the wet alarm valve is in the quasi working state, the upper chamber and the lower chamber of the valve body are filled with water. Under the action of water pressure and its own gravity, the resultant force of water pressure on the valve disc is downward, which means that the pressure of the upper chamber is slightly higher than the pressure of the lower chamber, and the valve disc is closed.
2) In case of fire or when the system opens the end water test device and the end water test valve, the water pressure at the system side drops rapidly due to the rupture or drainage of the closed sprinkler. When the pressure of the lower chamber is greater than the pressure of the upper chamber, the valve flap is opened by the alarm valve opened at the top of the lower chamber pressure. The water pressure in the lower chamber generally comes from the high-level fire water tank and the stabilized pressure pump.
3) The fire water in the lower chamber flows to the retarder, pressure switch and hydraulic alarm bell through the alarm pipeline. The hydraulic alarm bell gives an audible alarm, and the pressure switch sends an electrical signal to start the fire water pump.
2、 Composition of alarm valve
Wet alarm valve assembly:
Wet alarm valve body, system side pressure gauge, water supply side pressure gauge, compensator, water discharge test valve (normally closed), alarm control valve (normally open), alarm test valve (normally closed), filter, retarder, pressure switch and hydraulic alarm bell
Compensator: in order to cope with micro leakage and small leakage at the system side in the daily quasi working state, the valve body makes a small amount of water supplement from the lower chamber to the upper chamber through the compensator to maintain the pressure level of the upper and lower chambers.
Alarm test valve: test the function of alarm valve and alarm bell.
Retarder: the inlet and alarm pipeline are connected with each other, and the outlet is connected with the pressure switch. A filter shall be installed in front of the retarder. In case of leakage of the water distribution pipeline, the valve flap will be slightly opened, and the water will flow into the alarm pipeline. Because the water flow is small, it can be discharged from the orifice of the retarder, so it will never enter the hydraulic alarm bell and the pressure switch to avoid false alarm.
Pressure switch: the pressure switch is a pressure sensor, which is used to convert the pressure signal of the system into an electrical signal.
Hydraulic alarm bell: driven by hydraulic power, the water flows into the hydraulic alarm bell and forms a jet of expressway. The impact water wheel drives the bell hammer to rotate rapidly, and the bell cover will sound an alarm.
Post time: Jul-13-2022