1. Characteristics and classification:
• Features: The water flow indicator can observe the flow and turbidity of liquid, gas, steam and other media at any time, according to the impeller speed to roughly understand the flow rate of the medium, can convert the water signal into an electrical signal, play a monitoring and alarm role.
• Classification: According to the structure, it can be divided into impeller type, float type, straight-through type, three-way type, pendulum plate, glass tube type, pointer type, backstop type, etc. Connection methods include thread type, flange type, welding type, etc.
2. Working principle:
• The blade of the water flow indicator is perpendicular to the direction of the water flow. When the water flow in the pipe after the nozzle is opened, the force of the water will drive the blade or other sensing components to move. For example, the impeller type water flow indicator, the impeller is rotated by the water flow, and the micro-switch action is triggered by the drive shaft and other devices.
• After touching the micro switch, the delay line is connected, and the delay device starts to time. After reaching the set delay time, if the blade is still deflecting in the direction of the water flow and cannot return, the electric contact is closed and the output signal is generated. When the water flow stops, the blade and the action lever are reset, the contact is disconnected, and the signal is eliminated.