Flow Switch

A flow switch is a device used to detect the flow status (presence or absence of flow) of a fluid in a pipeline and trigger control or protection signals. It is widely used in water supply systems, HVAC equipment, industrial automation, and pump protection applications to ensure stable equipment operation and prevent dry running or system failures.

Flow switches operate by sensing changes in fluid movement. Mechanical flow switches typically use paddles or vanes that move with the fluid flow, while thermal and electronic flow switches detect flow based on heat conduction or signal changes. Depending on system requirements, flow switches can provide relay outputs, PNP/NPN outputs, or digital communication interfaces such as RS485 for integration into the user’s control system.

Depending on the medium and application, SUCH offers a variety of flow switches. Mechanical flow switches are typically used for water and low-viscosity liquids; they feature a simple design and are cost-effective. Thermal flow switches are better suited for detecting the flow of clean fluids and gases, offering higher sensitivity and no moving parts. Electronic flow switches, on the other hand, provide greater accuracy, adjustable setpoints, and compatibility with industrial automation systems.

Key factors in selecting a flow switch include fluid type (water, oil, air), flow range, installation method (in-line or insertion), output signal, and protection rating (e.g., IP65 or IP67). For industrial applications, temperature resistance, rated pressure, and compatibility with control systems such as PLCs or SCADA must also be considered.

Flow switches are widely used in flow monitoring for HVAC systems, dry-run protection for pump systems, circulation detection in cooling systems, and industrial processes requiring stable fluid control. They are key components for enhancing system safety, efficiency, and the reliability of automation.

If you require more advanced monitoring of flow-related parameters, you may also consider selecting relevant products, such as flow sensors for continuous measurement, level sensors for liquid monitoring, and pressure sensors for optimizing system control.