The multi-purpose Soliwave level switch is a non-contact method for detection of product levels in silos, tanks, chutes or free fall shafts (blocked shute detection). Detection is possible through the sides of non-metallic vessels or non-metallic windows (example PTFE) in the side of metal vessels. This makes microwave barriers an attractive technical solution for level detection in processes where impact, abrasion, corrosion and high temperatures prevent the use of intrusive and in-contact measurement principles.
Microwave barriers are suitable as a level limit switch for detection of all types of bulk solids, including: wood chips, wood dust, flour; plaster, cement, ash, gravel, sand and dried powders. Typical applications are to detect blockages in ore passes in mines, ‘filling’ shutes for flour and grain, but can also be used to detect ‘no filling’ in conveyor belt loading.
The Soliwave system comprises a field mounted transmitter and separate receiver with flanged or screwed connections, which can be mounted in any imaginable configuration, and up to 20 metres apart. A microwave signal is beamed from a transmitter across the vessel to a receiver and when the beam is broken by the rising material a signal is detected.
In high temperature or difficult installation applications, the use of reflection plates allows the system to “look around corners”. A remotely mounted evaluator provides a relay switch output by comparing the transmitted and received signals. Power supply is either 20-60 Vdc or 85-253 Vac. The benefit of a separate instead of compact evaluator is that it individually monitors the power consumption and status of both the transmitter and receiver, thereby providing high reliability, and improved failure detection and safety of all system components. Sensitivity and integration settings allow for detection even with falling product streams.
For non-intrusive, non-contact, and absolutely reliable detection of bulk solid levels, the Soliwave barrier is an extremely cost-effective and easy-to-install solution.
Photo Caption: The Soliwave transmitter and receiver for non-contact level measurement.