ZSFZ Groove Type Wet Alarm Valve

1. Description of Grooved Wet Alarm Valve ZSFZ:

The ZSFZ wet alarm valve is a one-way valve that only allows water to flow unidirectionally into the water spray fire extinguishing system and drives matching components to alarm under specified pressure and flow conditions. Together with water flow indicators, pressure switches, sprinkler heads, etc., it forms a wet automatic sprinkler system, which is a widely used fixed fire extinguishing system. The system's pipeline network is perennially filled with water under a certain pressure, remaining in a ready state. When a fire occurs in the protected area, the ambient temperature rises, causing the heat-sensitive element (glass bulb) in the sprinkler head to expand thermally due to the organic solution inside, generating significant internal pressure until the glass bulb shatters. This activates the sprinkler head to release water, automatically starting the entire system and triggering audible and visual alarms to achieve fire alarm, control, and extinguishment.

2. Product Structure and Working Principle of Grooved Wet Alarm Valve ZSFZ

1. Product Structure

As shown in Figure 1, the ZSFZ wet alarm valve device consists of a wet alarm valve, retard chamber, water motor gong, pressure switch, drain valve, filter, etc.

2.1.1 Wet Alarm Valve

This wet alarm valve is a cover plate type, primarily composed of the valve body, seat ring, and valve clapper. The entire valve body is divided into upper and lower chambers by the clapper. The upper chamber (system side) connects to the system pipeline network, while the lower chamber (water supply side) connects to the water source. The valve body is equipped with a seat ring featuring multiple grooved holes leading to the retard chamber's inlet pipe.

When the system is in the ready state, the grooved holes on the seat ring are covered and sealed by the valve clapper, blocking the alarm water passage to the water motor gong. When the pressure difference between the upper and lower chambers reaches a certain value, the clapper opens (differential pressure activation), allowing water to flow from the supply side to the system side, triggering the alarm gong and activating the fire extinguishing system to spray water. To prevent frequent opening due to pressure fluctuations, a small makeup water valve is installed on the clapper. This valve replenishes the pipeline network in case of minor leaks or water pressure fluctuations, balancing the pressures in the upper and lower chambers and stabilizing the clapper to avoid false alarms.

2.1.2 Retard Chamber

The retard chamber is a cylindrical water storage container with an inlet and an outlet. The lower end has an inlet connected to the alarm port of the alarm valve, and the upper end has an outlet connected to the water motor gong. Due to fluctuations in the system's water supply pressure, the valve clapper may open momentarily, allowing water to flow through the grooves and holes on the seat ring into the retard chamber. Since pressure fluctuations are brief, the clapper quickly resets (closes), resulting in only a small amount of water entering the retard chamber. This water is collected and discharged through the drain outlet at the bottom. The retard chamber's buffering action prevents false alarms caused by water pressure fluctuations. The time required for water to flow from the inlet to the outlet is the delay time, which for this device is 5–90 seconds. After water flow stops, any remaining water in the retard chamber is drained through the outlet, with a drainage time of less than 5 minutes.

2.1.3 Water Motor Gong

The water motor gong is a hydraulically driven mechanical device composed of a housing, impeller, hammer, and gong cover. When the valve clapper opens, water flows through the grooves and holes on the seat ring into the retard chamber. Once filled, water continues to the inlet of the water motor gong. Under certain water pressure, the impeller is driven, rotating the hammer arm to continuously strike the aluminum gong, producing an alarm sound.

2.2 Working Principle

The wet alarm valve device remains in a ready state with the system side filled with water under working pressure. When a fire occurs in the controlled area of the automatic sprinkler system, the heat-sensitive element in a closed sprinkler head on the system pipeline network heats up and activates, spraying water. This causes the pressure on the system side of the wet alarm valve to drop. Due to the pressure difference, the valve clapper automatically opens, allowing water from the supply side to flow into the system side to replenish the pipeline network, putting the entire network into an active fire extinguishing state. Simultaneously, a small portion of water flows through the holes on the seat ring to the retard chamber and water motor gong. Under certain pressure and flow conditions, the water motor gong sounds an alarm, and the pressure switch converts the pressure signal into an electrical signal to start the fire pump and auxiliary firefighting equipment for water replenishment and extinguishment. The pipeline network equipped with water flow indicators also activates, outputting electrical signals to allow the system control terminal to promptly identify the fire area, achieving the purpose of automatic fire sprinkling and alarm.

4. Installation and Commissioning of Grooved Wet Alarm Valve ZSFZ

4.1 Installation

4.1.1 Before installation, conduct a leakage test on the wet alarm valve at twice the rated working pressure, holding for at least 5 minutes with no leakage at the valve clapper. 4.1.2 The device should be vertically installed on pipelines that have passed pressure and flushing tests, paying attention to the water flow direction. The installation location should allow sufficient operating space for maintenance and servicing. 4.1.3 The system pipelines should be thoroughly flushed, coated with an anti-rust layer, and ensured to be free of debris and dirt. 4.1.4 All drain outlets should be separately piped to the sewer to maintain unobstructed and unified drainage. 4.1.5 Pressure gauges should be oriented for easy reading.

4.1.6 The positions of the water motor gong and alarm valve, along with the connected pipelines, are pre-installed at the factory. If pipeline rearrangement is necessary, the horizontal distance should be ≤20m, and the height difference should be ≤5m.

4.2.1 After completing the pipeline network installation, fill the system pipelines with water, slowly increase pressure while venting air from the pipelines, raise to the system working pressure, check the entire system for leaks, and after passing, conduct alarm and pipeline water supply tests.

4.2.2 Alarm Test: Open the end test valve (installed at the furthest end of the system). The water motor gong, pressure switch, and water flow indicator should perform corresponding alarm actions. Alternatively, open the drain ball valve (8) on the wet alarm valve device. When the flow rate is equivalent to one standard sprinkler head (15mm diameter, flow coefficient K=80±4), the water motor gong and pressure switch should perform corresponding alarm actions.

4.2.3 Open the alarm test ball valve (10). Water from the inlet side flows directly into the alarm device through the copper pipe, allowing testing of the pressure switch and water motor gong alarm performance without opening the valve clapper from the ready state.

4.2.4 Pipeline Water Supply Test: Open the drain ball valve (8). A large, steady flow of water should emerge, indicating unobstructed and normal water supply. Otherwise, check: vent and clear blockages in the pipeline system to ensure畅通无阻 (unobstructed flow).

5. Regular Inspection and Maintenance of Grooved Wet Alarm Valve ZSFZ

5.1 The rubber sealing surface on the valve clapper should be promptly cleaned of adhering dirt and foreign objects. The service life of rubber seals is generally within eighteen months; if worn or aged, replace promptly.

5.2 The small holes and sealing surfaces in the annular groove of the valve seat seal ring should be cleared of dirt and foreign objects. The sealing surfaces should not be scratched, and the small holes should remain clear. If unable to repair, replace.

5.3 Regularly clean dirt from the filter in the alarm valve device to keep the pipelines clear.

5.4 Inspect and clean dirt inside the retard chamber; the throttling small holes should not be blocked by foreign objects.