The Piezoelectric-driven vibration level switch detects high, mid, and low levels in vessels with powders and bulk solids and is suitable for a wide range of applications. When the blade is covered, the vibration is dampened by material, and an electronic circuit forces a relay to switch, indicating a covered condition. When the blades are uncovered, the vibration will restart and the relay will indicate an uncovered condition. In this application, the vibrating blades or rod are driven by a piezo crystal excited by the electronics system. The driving signal changes the physical shape of the piezo crystal, which causes the mechanical vibration of the blades/rod, much like a piezo type loudspeaker. The perfectly balanced mechanical system then resonates at the frequency of the drive signal. The blade/rod design is carefully balanced to provide a very low loss tip sensitive vibrating system and requires a very small amount of energy to keep the system vibrating. A second piezo crystal is used to detect the vibration of the blades, in turn signaling to the electronics if the blades are covered.

• Carbon black, plastics, fly ash, feed, seed, grain, food, chemicals, and other materials.