Point Level Measurement For Liquids
There are several principles for measuring Point levels in liquids:
The basis of point level detection with vibrating level switches is a tuning fork, i.e. a vibrating fork. If the vibrating probe comes into contact with the medium, the oscillation rate changes and the vibrating level switch outputs a switching command. Vibrating level switches are used as overfill protection or empty alarm.
In capacitive point level measurement, capacitive sensor and vessel form the two electrodes of a capacitor. Any change in capacitance due to a level change is converted into a switching signal. Thanks to shortenable cable and rod versions, the level switches can be adapted to any application and often serve as overfill protection, dry run protection, oil/water detection and foam detection.
When the electrodes of the conductive point level sensor come into contact with a conductive liquid, a small alternating current begins to flow. The electronics responds by triggering a switching command. Conductive point level sensors are used in all areas of industrial metrology, e.g. as overflow protection, pump control or dry run protection.
The microwave barrier works like a light barrier: If the microwave beam between transmitter and receiver is blocked by the medium, the measuring signal is damped. This change is detected by the receiver and converted into a switching signal.