The HYDAC flow switches of the HFS 2000 series are based on a variable area float principle. The measuring medium deflects a springloaded float in the direction of flow, depending on the flow rate. A reed contact is fitted outside of the device, therefore separated from the fluid circuit. When the magnet inside the float reaches the pre-set position, the reed contact will switch.

To protect it from external influences, the reed contact is encapsulated in a housing designed to allow steplessly variable adjustment. The devices are designed to be capable of monitoring threshold values reliably, even when the viscosity fluctuates.