A basic flow switch is a device used to detect the presence or absence of fluid (liquid or gas) flow in a pipe or duct. When it comes to detecting gas flow in pipes, the principle is similar to that of detecting liquid flow, but the construction and materials of the flow switch are designed to handle gas flow.
Here's a basic explanation of how a flow switch detects gas flow in pipes:
Flow Sensor: The flow switch contains a flow sensor, which is a crucial component responsible for sensing the flow of gas. Various types of flow sensors can be used, such as paddle-wheel sensors, turbine sensors, or thermal dispersion sensors, depending on the specific application and requirements.
Pressure Difference or Velocity Measurement: In gas flow detection, the flow sensor measures the pressure difference or velocity of the gas as it passes through the pipe. As the gas flows, it exerts a force on the sensor or causes a change in the sensor's physical properties (e.g., rotational speed, temperature, etc.).
Threshold Setting: The flow switch is equipped with a threshold setting that determines the minimum flow rate required to trigger the switch. This threshold can be adjusted based on the desired sensitivity and the specific gas flow rate that needs to be detected.
Switch Mechanism: Once the gas flow rate exceeds the set threshold, the flow switch triggers a switch mechanism. This can be a mechanical relay, an electronic switch, or any other type of switching element.
Output Signal: The flow switch's switch mechanism provides an output signal when activated. The signal can be used to activate alarms, control other devices, or simply indicate the presence of gas flow.
Installation: The flow switch is typically installed in the gas pipe or duct. Proper placement and orientation are essential to ensure accurate detection of gas flow.
It's important to note that flow switches can be used for a wide range of applications beyond gas flow detection, such as liquid flow detection in pipes, monitoring HVAC systems, protecting pumps from running dry, and more.
When selecting a flow switch for gas flow detection, it's crucial to consider factors such as the gas composition, pressure, temperature, flow rate range, and the specific requirements of the application to ensure optimal performance and reliability. Always refer to the manufacturer's guidelines and specifications to choose the appropriate flow switch for your needs.