A basic flow switch is a device used to detect the flow of gas or liquid in a pipe and trigger an action based on that flow. It is commonly used for various applications, such as monitoring gas flow in industrial processes, ensuring proper ventilation, or detecting leaks in a gas system. The operation of a basic flow switch is relatively simple and typically involves the following components:
Flow Sensing Element: The heart of the flow switch is the flow sensing element. It is designed to respond to changes in the fluid (gas or liquid) flow passing through the pipe. The sensing element can vary based on the type of flow switch and the application. Some common flow sensing elements include paddle wheels, vane switches, or thermal sensors.
Paddle Wheel or Vane: In some flow switches, a paddle wheel or vane is used as the flow sensing element. The paddle wheel is placed inside the pipe, perpendicular to the flow direction. When the fluid flows through the pipe, it causes the paddle wheel to rotate. The rotation of the paddle wheel is then used to trigger the switch.
Thermal Sensors: In other flow switches, thermal sensors may be used as the flow sensing element. These sensors measure the temperature difference between the flowing fluid and the ambient environment. As the flow rate increases, more heat is carried away by the fluid, resulting in a temperature change that the thermal sensor can detect.
Switch Mechanism: The flow switch is equipped with a switch mechanism, which can be either mechanical or electronic. When the flow rate exceeds a certain threshold (set point), the switch mechanism is activated.
Set Point Adjustment: Flow switches often have a set point adjustment feature that allows users to configure the flow rate at which the switch should trigger. This allows for customization to suit different applications and flow requirements.
Output Signal: Upon detecting the flow, the flow switch will generate an output signal, which can be used to control other devices, such as pumps, fans, alarms, or safety systems. Depending on the design, the output signal can be a simple ON/OFF signal or an analog signal proportional to the flow rate.
In summary, a basic flow switch detects gas flow in pipes by using a flow sensing element that responds to changes in fluid flow, triggering a switch mechanism when the flow rate exceeds the set point. This activation of the switch then produces an output signal for further actions or control.