The devices are equipped with a spring-loaded piston located within a cylindrical metering tube incorporating a calibrated orifice. When flow passes through the STAN, the process fluid displaces the piston against the spring force, making the piston position directly proportional to the volumetric flow rate.

A magnet integrated into the piston transmits its movement contactlessly to a mechanical indicator mounted externally on the housing, allowing immediate reading of the flow rate on the scale.

A bistable reed switch (normally open contact), mounted externally on the housing, is actuated when the magnetized piston passes its position. The flow rate to be monitored (switching point) can be continuously adjusted by repositioning the switch along the external scale.

The actual flow rate may exceed the specified measuring range without causing damage to the device; however, the resulting pressure drop will increase accordingly.

The devices are intended exclusively for use with particle-free liquids and must be protected from external magnetic fields.