1. Working principle
After the alarm valve is opened, the alarm pipeline is filled with water, and the pressure switch is connected to the electric contact after being subjected to the water pressure, and outputs the signal of opening the alarm valve and starting the water supply pump, and the electric contact is disconnected when the alarm valve is closed.
2. Setting requirements
1). The pressure switch is installed on the alarm pipe after the outlet of the system pipe network or alarm valve delayer. The automatic sprinkler system shall use a pressure switch to control the fire water pump and the stabilized pressure pump, and shall be able to adjust the pressure of starting and stopping the stabilized pressure pump.
2). The water flow alarm device of the deluge system and the fire separation water curtain system should adopt a pressure switch.
3. Inspection requirements
1). The nameplate is clear, with safety operation instructions and product instructions.
2). Each component must not have loose mechanism, obvious processing defects, and the surface must not have obvious defects such as rust, coating peeling, blistering, and burrs.
3). Test the action performance of the pressure switch, open the pressure switch, connect its normally open or normally closed contact with a multimeter, and make the pressure switch act, and check whether the normally open or normally closed contact of the pressure switch can be reliably turned on and off.
4. Installation requirements
1). The pressure switch is installed vertically on the pipe leading to the hydraulic alarm bell, and cannot be disassembled or modified during installation.
2). Install the pressure control devices on the pipe network according to the fire protection design documents or the installation drawings provided by the manufacturer.
3). The lead-out line of the pressure switch should be locked with a waterproof casing, and the technical inspection should be carried out by observation and inspection.
Five, chain and linkage start pump
1. Interlock start pump
1) The fire water pump in the fire hydrant system should be directly activated by the pressure switch on the outlet pipe of the fire water pump, the flow switch on the outlet pipe of the high-level fire water tank, or the pressure switch of the alarm valve. The signal of the pressure switch to start the fire pump should not be affected by the automatic or manual state of the linkage controller. When the water pump control cabinet is in the manual state, the pump start signal sent by the pressure switch will not directly start the fire pump.
2) The pressure stabilizing pump shall be controlled by the automatic start-stop pump pressure switch or pressure transmitter set on the fire water supply pipe network or the air pressure water tank.
3) In the automatic sprinkler system, the action signal of the pressure switch is used as the chain trigger signal to start the sprinkler pump.
2. Linkage to start the pump (illustrated in "Code for Design of Automatic Fire Alarm System")
1) The action signal of the pressure switch of the alarm valve of the wet type, dry type, deluge and water curtain system and the alarm signal of any fire detector or manual alarm button in the protection area of the alarm valve are used as the linkage control signal for starting the fire pump
2) When the water curtain system is used for fire shutter protection and fire separation, the action signal of the pressure switch of the alarm valve and the alarm signal of any fire detector or manual alarm button in the protection area of the alarm valve are used as the linkage to start the fire pump control signal.
Six. Others
1. The rated working pressure of the pressure switch should not be lower than 1.2MPa.
2. The pressure switch is usually set on the main pipeline of the fire pump room or on the alarm valve, and the flow switch is usually set on the outlet pipe of the high-level fire water tank.
3. For automatic sprinkler system and pressure switch, check its control function according to the actual installation quantity.
4. For the deluge system and the fire separation water curtain, the water flow alarm device should adopt a pressure switch. The deluge system and the water curtain system use open nozzles. Usually there is no water in the pipeline after the alarm valve outlet. After the system is started, the water in the pipeline is filled with water. The flow rate of the water in the pipeline is fast, which is easy to damage the water flow indicator.
5. Reliable automatic control is required for the start and stop of the stabilized pump. Therefore, it is required to use a fire pressure switch, and it is required to adjust the start and stop pressure of the stabilized pump according to the working pressure of the nozzle at the most unfavorable point.
6. The foam-water deluge system should be equipped with deluge valves and hydraulic alarm bells, and a pressure switch should be installed on the outlet pipeline of each deluge valve, but the single-zone system with less than 10 nozzles may not be equipped with deluge valves and pressure switches. switch.
Post time: Jul-04-2023