The structure and working principle of the water flow indicator The water flow indicator is composed of diaphragm components, adjusting screws, delay circuits, micro switches and connecting parts. According to the shape of the blade, it can be divided into two types: plate type and paddle type. Plate type blades are mostly made of rubber material, which has a relatively large area and high sensitivity; paddle type blades mostly use thin copper. According to the connection mode, it is divided into plug-in type and tube type. The connecting parts of the plug-in water flow indicator are mostly flange bases. The specific structure is shown in Figure 1. The flange base is welded to the corresponding opening of the water distribution pipe during installation. There is an American saddle type water flow indicator that also belongs to the plug-in connection method. , The connecting part is a saddle; the tubular connecting part is a small section of the main pipe connected with the water flow indicator. Generally, the small diameter is connected by thread, and the large diameter is connected by flange. The paddle blade type plug-in water flow indicator is commonly used in our country. When a fire occurs in a certain area of the wet alarm valve fire extinguishing system, the temperature-sensitive glass bulb of the sprinkler is ruptured and the fire is started. The water flow in the water distribution pipe pushes the blade through the diaphragm. The component makes the micro switch close the micro switch and turn on the relevant circuit. Generally, it is equipped with a delay function to determine the water flow is valid and then give a water flow signal, which is transmitted to the alarm controller to display the fire alarm signal of the zone.
