A basic flow switch is a device used to detect the presence or absence of fluid flow (such as gases or liquids) within pipes or systems. It operates on a simple principle: when flow occurs, it triggers a mechanism that generates an electrical signal or mechanical action. Here's a general overview of how a basic flow switch detects gas flow in pipes:
Design: A basic flow switch typically consists of a housing with an inlet and an outlet where the fluid (in this case, gas) flows through. Inside the housing, there's a mechanism that responds to the flow of gas.
Sensing Element: The heart of the flow switch is a sensing element that can detect changes in fluid flow. There are several types of sensing elements used in flow switches, including:
Paddle Type: This type includes a paddle or vane that is placed in the path of the gas flow. When flow occurs, the force of the gas pushes the paddle, causing it to move. This movement is then translated into a mechanical action, such as pressing a switch or triggering a magnet.
Vane Type: Similar to the paddle type, a vane is placed in the gas flow path. The force of the gas flow causes the vane to move, which in turn triggers the flow switch.
Paddleless Type: In this design, there's no physical paddle or vane. Instead, the gas flow exerts pressure on a diaphragm or a flexible element. This pressure deformation is then used to activate the switch.
Thermal Dispersion Type: This type relies on the difference in temperature between the gas and the sensor. As gas flows over the sensor, it carries away heat, causing a temperature difference. This temperature change is detected and used to determine flow.
Mechanical Action or Electrical Signal: Once the sensing element detects the gas flow, it triggers a mechanical action or generates an electrical signal. This can involve mechanisms like activating a switch, moving a magnet, or changing the state of an electrical circuit.
Output: The mechanical action or electrical signal generated by the flow switch can be used for various purposes. It might trigger an alarm, activate a pump or fan, open or close valves, or send a signal to a control system to monitor and manage the flow.
Adjustment and Sensitivity: Flow switches often have adjustments to set their sensitivity threshold. This allows you to configure the switch to trigger based on a specific minimum flow rate. This adjustment ensures that the switch is responsive to the desired flow conditions.
In summary, a basic flow switch detects gas flow in pipes by using a sensing element that responds to the force, pressure, or temperature changes caused by the gas flow. This response then triggers a mechanical action or generates an electrical signal that can be used for various control or monitoring purposes.