A basic flow switch is a device designed to detect the presence or absence of fluid flow within pipes or ducts. It operates based on the principles of fluid mechanics and uses a simple mechanism to trigger a response when flow occurs. Here's a general explanation of how a basic flow switch works:
Construction: A basic flow switch typically consists of a housing that encloses a sensing element and an electrical switch.
Sensing Element: The sensing element is the part of the flow switch that directly interacts with the fluid flow. It is often a paddle or vane that is positioned in the path of the flowing fluid. When the fluid flows through the pipe, it exerts force on the sensing element, causing it to move.
Spring Mechanism: The sensing element is connected to a spring or a similar mechanism. The spring provides resistance to the movement of the sensing element. The spring's tension can be adjusted to set the flow threshold at which the switch activates.
Electrical Switch: The sensing element is linked to an electrical switch, which can be either normally open (NO) or normally closed (NC). When the fluid flow is insufficient to move the sensing element past the set threshold, the switch remains in its default state (NO or NC).
Flow Activation: When the fluid flow reaches or exceeds the predetermined threshold, it exerts enough force on the sensing element to overcome the tension of the spring. As a result, the sensing element moves, and this movement triggers the electrical switch to change its state.
Switch Response: Depending on the type of switch used, the activation of the flow switch can either open or close the circuit. For example, a normally open (NO) switch will close the circuit upon activation, while a normally closed (NC) switch will open the circuit.
Output Signal: The change in the switch's state can be used to indicate the presence or absence of fluid flow. This signal can be used for various purposes, such as activating alarms, starting or stopping pumps, or monitoring flow in a system.
It's important to note that basic flow switches are typically used in applications where the fluid flow rate is relatively constant and not too high. For more complex and precise flow measurement and control tasks, specialized flow meters and flow controllers are used.