The vibration level indicators are suitable for level measurements in liquids, solid powder and solids in liquids, to detect level states only.
The fork probes are preferable for applications on very fine powdery clean and solid liquids, while the rod, foil and membrane probes are preferable on dirty and viscous liquids, and fine powdery solids.
They are composed of a probe which, having vibrated at its natural resonance frequency in air, varies the frequency of vibration in the presence of the liquid or solid to be detected.
This frequency variation is detected by a second piezoelectric element which, by means of a detector and amplifier circuit, drives a final relay to a possible visual alarm signal.
The vibration level sensors can be installed vertically or laterally to the tank to be detected and do not require calibration.
The measurement probe is vibrated at the frequencies typical of:
400 Hz for liquids
80-160 Hz for powdery solids
from a piezoelectric element to the resonance frequency in air.
An increase in the level, such as to touch the measuring probe, causes a variation of the vibration frequency, of about 20%, with respect to the resonance frequency in air.
This frequency variation is detected by a second piezoelectric element which, by means of a detector and amplifier circuit, drives a final relay and a possible visual alarm signal.
They do not need calibration
Suitable for clean and dirty liquids, and for solid fine powders even in liquids