Method for monitoring a screw centrifuge to identify dynamic changes in relative angular offset between an output shaft and a transmission input shaft

A method for monitoring a screw centrifuge, the method comprising:

• a) providing the screw centrifuge, which comprises a rotatable drum, a rotatable screw arranged in the rotatable drum, a primary motor configured to drive the rotatable drum, and a secondary motor configured to drive the rotatable screw, and a transmission arranged between the primary and second motors and the rotatable drum and the rotatable screw, transmission input shafts for the primary motor and the secondary motor, an elastic element between an output shaft of the secondary motor and the transmission input shaft for the secondary motor, wherein pulse-generators are arranged on both sides of the elastic element on the output shaft of the secondary motor and on the transmission input shaft, to each of which there are assigned proximity-sensors, and processing a product with the screw centrifuge so that solids are separated from the product and the separated solids are conveyed out of the rotatable drum by the rotatable screw;
• b) measuring, using the pulse-generators and proximity sensors, a relative angular offset over time between the output shaft and the transmission input shaft on both sides of the elastic element connecting the output shaft and the transmission input shaft;
• c) evaluating the measurements from step b) to determine whether the relative angular offset over time exceeds a deviation limiting value;
• and
• d) outputting a warning signal and/or varying of one or more operating parameters for actuating the screw centrifuge responsive to a determination that dynamic changes of the relative angular offset over time occurring during the evaluation of the measurements in step c) exceeds the deviation limiting value, wherein the dynamic changes of the relative angular offset are changes in the relative angular offset that are not constant over a predetermined time interval.