A basic flow switch is a simple mechanical device used to detect the flow of gas or liquid in pipes. It is commonly employed in industrial and commercial applications to monitor fluid flow and trigger specific actions based on flow conditions. The working principle of a basic flow switch involves the use of a vane or paddle that responds to the flow of the gas in the pipe. Here's a general overview of how it works:
Physical Setup: The flow switch is installed in the gas pipe or duct at a specific location where flow monitoring is required. It consists of a housing with an inlet and an outlet through which the gas flows. Inside the housing, there is a vane or paddle mechanism that can move freely.
Flow Detection: When the gas starts flowing through the pipe, it exerts pressure on the vane or paddle inside the housing. The magnitude of this pressure depends on the flow rate of the gas. As the flow rate increases, the pressure on the vane or paddle also increases.
Actuation Threshold: The flow switch is designed with an actuation threshold or setpoint. Once the pressure on the vane or paddle reaches a certain level, corresponding to a specific flow rate, it triggers the switch to actuate.
Switch Activation: When the pressure on the vane or paddle reaches the actuation threshold, the switch mechanism inside the flow switch is triggered. This typically involves a mechanical switch, which may open or close an electrical circuit.
Output Signal: The flow switch's actuation results in a change of state of the electrical circuit it controls. For example, if it's normally closed, it opens the circuit when actuated. Conversely, if it's normally open, it closes the circuit when actuated. This change in the circuit's state can be used to activate alarms, control valves, motors, or any other devices connected to the flow switch.
It's important to note that the responsiveness and sensitivity of a flow switch can be adjusted by setting the actuation threshold to match the required flow rate. These switches are relatively simple, cost-effective, and reliable solutions for gas flow detection in pipelines, though they may not be as precise as more advanced flow measurement devices like flow meters. As with any industrial device, proper installation and regular maintenance are essential for ensuring accurate and reliable operation.