The efficient turning of organic materials – loosening, lifting and aerating – is vitally important in industrial composting. Special mobile equipment ensures fast drying of materials, optimal decomposition and reliable sanitization, processing between 500 and 6800 cubic meters of earth per hour. A German manufacturer has introduced machine speed monitoring by sensor. A sensor located in the rotor counts the passing teeth of a rotating mechanical disk. From the number of teeth per second, the controller then calculates the final speed. Perfect sensor operation is required under these particularly harsh conditions. In addition to permanent vibration and shaking, the inductive sensor is also constantly exposed to dust, moisture, and temperatures from 70 to 80°C (158 to 176°F). Since the location of the sensor in the rotor is hard to access, the sensor must be very durable and low maintenance to avoid time-consuming repairs.
Contrinex inductive sensors from the FULL INOX family, WASHDOWN range, are perfect for this application. Made from a single piece of V4A stainless steel, including the sensing face, they have no covers, caps or welding seams and are the most robust inductive sensors on the market. They resist shock, vibration, impact and abrasion and almost any exposure to dirt, gases, or liquids such as oil, water and cleaning agents. Functionally stable at temperatures from -25 to +85°C (-13 to 185°F), they are also insensitive to core breakage. Thanks to the long operating distances of these sensors (three times greater than the norm) a compact and efficient design was possible using the M12 size. A long operating distance allows the sensor to be mounted well away from the rotating disk’s passing teeth. Setup is also straightforward, as installation tolerances are less critical. A sensor version with plug connector was chosen to allow speedy replacement if necessary. Even under the harsh operating conditions of this application, FULL INOX sensors last several years and downtime attributable to faulty sensors is minimal. Their long service life contributes to a reduction in repair costs.