Wet alarm valve structure, installation and commissioning and precautions

Wet alarm valve working principle is to rely on pipe network system side hydraulic lift to achieve. To ensure the use of alarm valve, and extend the life expectancy, master the principle of wet alarm valve is necessary.


The standard configuration of the wet alarm valve includes: pressure gauge, delayer, pressure switch, hydraulic alarm, and the necessary fittings and valves.


The retarder is a cylindrical water storage container with a water inlet and a water outlet. The water inlet at the lower end is connected with the alarm port of the alarm valve, and the water outlet at the upper end is connected with the hydraulic alarm bell. Due to the fluctuating pressure in the system water supply, the valve flap can be instantly opened. The water flow enters the retarder through the groove and the hole on the seat ring first. Since the pressure of the water source fluctuates for a short time, the valve flap can automatically reset (Closed) so the amount of water entering the retarder is small enough to collect water from the retarder and expel through the drain at the bottom. The delay time of the retarder acts to prevent the water pressure from fluctuating and causing a hydraulic alarm error Call the police. The time required for the water to flow from the inlet to the outlet of the retarder is a delay time, and the present device is 5 to 90 seconds. After the water flow stops, the water left in the retarder is discharged from the drain, and the required time ) Is less than 5min.

Water alarm

Hydraulic alarm is a hydraulic drive mechanism. By the shell, impeller, bell hammer and bell cover and other components. When the valve flap is opened, the water flows into the retarder through the groove and the small hole on the seat ring. When the valve flap is full, it continues to flow to the water inlet of the hydraulic bell. Under a certain flow pressure, the impeller drives the bell and arm to rotate The bell rattles the aluminum bell and gives an alarm bell.

working principle

Wet alarm valve device is in a long-term state, the system side is full of pressure water, sprinkler system control area fire, the system pipe network of closed sprinklers in the heat-sensitive components by automatic blasting water spray, wet The pressure on the side of the alarm valve system is decreased. Under the action of pressure difference, the valve flap opens automatically. The water on the water supply side flows into the system side to replenish the pipe network. The entire pipe network is in an automatic sprinkler state. At the same time, a small part of the water flows through the holes in the seat ring to the delaying device and the hydraulic alarm bell. Under certain pressure and flow conditions, the hydraulic alarm sounds and the pressure switch converts the pressure signal into an electrical signal and starts the fire pump And auxiliary fire extinguishing equipment to replenish fire and extinguish the fire. The pipe network equipped with water flow indicator will also act accordingly to output electric signals so that the system control terminal can detect the fire in time and achieve the purpose of automatic sprinkler and alarm.

Wet alarm valve is only a one-way water flow to the sprinkler system, and the required pressure and flow control components driven by a check valve. It is a wet fire sprinkler system with flow indicators, pressure switches, sprinklers and more. It is a very versatile, fixed fire extinguishing system. The system of pipelines filled with water with certain pressure all the year round is in the state of servo work for a long time. When a fire occurs somewhere in the protected area, the ambient temperature in the area is increased. The organic solution in the heat sensitive element (glass ball) Thermal expansion occurs great internal pressure until the glass bulb crushing, which open the nozzle spray, and automatically start the entire system, audible and visual alarm signals to achieve the fire alarm and control of fire, the purpose of fighting a fire.

In the servo state, the water pressure slightly fluctuates, the role of the bypass balance valve up and down the valve flap pressure balance, and the valve pressure side is greater than the next pressure face, the valve will not open false alarm. When there is fire and blasting causes the pipe network system side water pressure to drop, the pressure difference between the water supply side and the system side will open the valve flap to the open nozzle to continuously supply fire.

Wet alarm valve between the alarm port and the delay between the control ball valve servo state must be kept fully open and locked, and the test alarm control valve must be closed. When it is necessary to test the alarm, remove the locking device that controls the ball valve between the alarm port and the retarder and close it. At this point open the test alarm control valve can be alarm test. Immediately after the test will be two control valve restored to its original state.

Cover type alarm valve, mainly by the valve body, seat ring and valve flap three parts, the valve body is divided into upper and lower chamber, the upper chamber (system side) and the system pipe network, the lower chamber (water supply side ) Is connected to a source of water and is provided with a seat ring in the valve body, on the seat ring there are a plurality of channel holes leading to the retarder inlet pipe.

When the system is in the servo state, the groove on the seat ring is covered by the valve flap, the alarm waterway leading to the hydraulic alarm is blocked; when the pressure difference between the upper and the lower reaches a certain value, the valve flap is opened Differential pressure start), the water flow from the water supply side to the system side, the alarm bell, water system water; when the pressure on the lower open frequently, with a small valve on the flap, when the system side of the pipe network has a slight permeability Leakage or water pressure fluctuations, you can fill the water supply valve to the network, balance the pressure on the lower chamber, stabilizing the valve, thus avoiding false alarms.

Wet fire extinguishing system with wet alarm valve must be installed in a building with an ambient temperature of at least 4 ° C so as to prevent it from losing its fire protection function due to icing.

Installation and commissioning

Wet alarm valve should be installed before the leak test, the test pressure is 2 times the rated working pressure, packing more than 5min, the valve should be no leakage;

The device should be installed vertically in the pressure test and flushing qualified pipeline, pay attention to the direction of the water, the installation location should be considered for maintenance, maintenance, adequate operating space;

System piping should be thoroughly washed, the tube should be coated with anti-rust layer to ensure that there is no dirt in the pipeline dirt;

Drainage pipe access to the sewer access alone, to maintain unimpeded unified drainage;

Pressure gauge should be turned to see the reading position;

Hydraulic alarm and alarm valve position, the connection of the pipeline has been installed at the factory ready, if the need to re-arrange the pipeline, the horizontal distance ≤ 20m, height ≤ 5m

After the installation of the pipe network system, water is filled into the system pipeline, and the air in the pipeline is slowly boosted and discharged to the working pressure of the system to check whether there is leakage in the whole system and then alarm test and pipe Road water supply test.

Alarm test: open the end of the test valve (installed in the system at the end), hydraulic alarm, pressure switch and flow indicator, should be the appropriate alarm action. Or open the drain ball valve (8) on the wet alarm valve device, when the flow rate is equivalent to a standard nozzle (diameter 15mm, flow coefficient K = 80 ± 4), the hydraulic alarm and pressure switch should be the appropriate alarm action .

Open the alarm test ball valve (10), the water flow into the alarm device directly from the copper pipe, the valve does not open the servo state, you can also test the pressure switch and hydraulic alarm alarm performance test.

Pipeline water supply test: Open the drain ball valve (8), there should be a steady flow of a large number of water flow, indicating normal water supply pipeline, or to check: pipeline system to remove exhaust blockage, to ensure smooth flow.

Routine maintenance precautions

1, check the sealing surface of the rubber gasket on the valve disc to remove the dirt and foreign matter attached to the rubber gasket; the service life of the rubber seal is usually replaced within 18 months if worn or aged.

2, six months to check the flow of water pressure, check open the drain valve, bell alarm sound, this time, the pressure gauge should not show a significant decrease in pressure, if the decline is more significant, check whether the valve is blocked or not open the largest ; If the pressure gauge shows the pressure drop is obvious, and the alarm does not alarm, should check the wet alarm check valve flap is normal.

3, should be a half months to check whether the rotation of the alarm bell is normal, check open the drain valve, the alarm valve automatically open due to water pressure difference, the water flow into the delay after 20-30 seconds, the alarm bell alarm.

If the alarm does not sound, should check the entire alarm pipe, remove the scale, sediment and dirt, so that water flow, to prevent alarm failure. If the bell calibration cock is closed, the alarm still sound, you should check the calibration cock is closed, the alarm valve in the annular groove is the accumulation of obstacles, the alarm valve under the rubber is aging or wrinkles. Use iFire fire treasure processing daily for Paul, accurate grasp of equipment information, these faults should be promptly ruled out.

4, a year should check the seal and the seat ring ring groove seal and sealing surface, remove dirt or foreign body; sealing surface should not be scratched, the hole remains unobstructed, can not be repaired should be replaced.

5, according to the water quality of fire water, regularly open the outlet on the filter, clean up dirt, keep the pipeline open.

6, check and clean the dirt within the delay device, throttle holes should not be blocked foreign body.

7, pay attention to the daily fire water level and water pressure and the corresponding state valve is in line with norms.

False alarm handling

When a false alarm is detected, check whether the entire pipe network leaks, check whether the delay device overflow hole is clogged or the drainage is poor. Open the bleed test valve to drain water from the system or check for blockage of the water supply network.

Check the wet alarm valve disc assembly and valve seat between the lax seal, so that a large amount of water into the retarder.

Check the pipe network in the nozzle for unexpected reasons cause the release mechanism to start.

After finding out the reason of the false alarm, it should be promptly handled to ensure that the system is in a good standby state at any time.

Use iFire Fire Po first alarm information.

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