What are the commonly used types of alarm valves?

Wet alarm valve

The wet alarm valve is the main component of the wet automatic sprinkler system. It is installed on the main water supply main pipe and connects the water supply equipment and the water distribution pipe network. It is a A check valve that only allows water flow to flow into the water distribution pipe network in one direction and alarms at a specified flow rate. Before the system operates, it isolates the pipe network from the water flow to avoid water use and possible pollution; when the system is turned on, the alarm valve Open and connect the water source and water distribution pipe; when the alarm valve is opened, part of the water flow passes through the annular groove on the valve seat and is sent to the hydraulic alarm bell through the signal pipe to send out an audio alarm signal.

Mainly used for wet automatic sprinkler fire extinguishing systems and installed on their risers. The wiring of the wet alarm valve is shown in Figure 5-19.

Figure 5-19 Wiring of wet alarm valve

Wet alarm valve usually has equal water pressure before and after the valve core (water passes through the water pressure balance hole in the guide pipe to maintain water pressure before and after the valve plate) pressure balance). Due to the different weight of the valve core and the total pressure of water before and after the valve core, the valve core is in a closed state (the total pressure above the valve core is greater than the total pressure below the valve core). When a fire occurs, the closed sprinkler sprays water. Because the water pressure balance hole has no time to replenish water, the water pressure above the alarm valve drops. At this time, the water pressure under the valve is greater than the water pressure above the valve, so the valve plate opens to supply water to the standpipe and pipe network. , simultaneously sending out a fire alarm signal and starting the fire pump.

Dry alarm valve

Dry alarm valve is mainly used in dry automatic sprinkler systems and dry and wet automatic sprinkler systems. Its function is to separate the air in the sprinkler pipe network and the pressure water in the water supply pipe, so that the sprinkler pipe network always remains in the dry pipe state. When the sprinkler head is turned on, the air pressure in the pipe network drops and the dry valve disc opens. , water enters the sprinkler pipe network through the alarm valve, and at the same time, part of the water flow enters the signaling facility through the annular groove of the alarm valve for alarm.

The dry alarm valve consists of a valve body, a differential double-disc valve plate, an inflatable plug, a signal pipe network, a control valve, etc. The structure is shown in Figure 5-20.

Figure 5-20 Structure of dry alarm valve

1—valve body; 2—differential double disc valve plate; 3—inflatable plug; 4—pressure gauge in front of the valve; 5—pressure gauge behind the valve; 6—angle valve; 7—check valve; 8—signal tube; 9, 10, 11—stop valve; 12—small orifice valve; 13—main gate valve

Rain Deluge alarm valve

Deluge valve is used in deluge sprinkler systems, pre-action sprinkler systems, water curtain systems and water spray fire extinguishing systems. The inlet side of this valve is connected to the water source, and the outlet side is connected to the system pipeline and sprinkler head. Generally empty tubes, only inflated in pre-action systems. The opening of the deluge valve is controlled by various fire detection devices. Deluge valves mainly include lever type, diaphragm type, piston type and temperature sensing type. Their important characteristics are shown in Table 5-12.

3 standard § Types and characteristics of commonly used deluge valves Table 5-12