1、 Working principle
The dead weight of the valve disc and the total pressure difference of the water before and after the valve disc will cause the total pressure above the valve disc to be always greater than the total pressure below the valve core, so that the valve disc is closed. In case of fire, the closed sprinkler sprays water. Because the water pressure balance hole cannot make up water, the water pressure on the alarm valve drops. At this time, the water pressure behind the valve flap is less than the water pressure in front of the valve flap, so the valve flap opens the water supply. At the same time, the water will enter the pressure switch, hydraulic alarm bell, delay device and other facilities along the annular groove of the alarm valve, and then send out the fire alarm signal and start the fire pump at the same time.
2、 Installation problems
1. The wet alarm valve, hydraulic alarm bell and retarder shall be able to be installed and maintained on site with common tools.
2. Sufficient maintenance space shall be reserved near the installation positions of the wet alarm valve, hydraulic alarm bell and delay device to ensure that the machine can be repaired in the shortest time. The height of the alarm valve from the ground shall be 1.2m.
3. The installation height, installation distance and pipeline diameter between the wet alarm valve, hydraulic alarm bell and delay device shall ensure that the function must meet the relevant requirements.
4. The hydraulic alarm bell is one of the main parts of the wet alarm valve. The hydraulic alarm bell must be installed near the place where people are on duty. The diameter of the connecting pipe between the alarm valve and the hydraulic alarm bell shall be 20mm, the total length shall not be more than 20m, the installation height shall not exceed 2m, and the drainage facilities shall be set.
3、 Problems needing attention during work
1. The piping system must be checked regularly for blockage. The inspection method is: close the valve on the pipeline leading to the delay device and the hydraulic alarm bell, and then open the ball valve of the main drainage pipe. If a large amount of water flows out, it indicates that the pipeline is in a smooth state.
2. The working state of the alarm system must be checked regularly. Generally, the water can be discharged through the end test device of the automatic sprinkler system to confirm whether the pressure switch, hydraulic alarm bell and wet alarm valve can be normally supplied with water.
Post time: May-07-2022