Control circuit for centrifuge with worm ejector drum - has reduction gear pulley acting as electrical current generator

摘要

A centrifuge for sepg. fluid and solid matter, embraces an outer and an inner drum, the inner drum being laid out as a worm conveyor. The centrifuge is further equipped with a control system for maintaining by means of proportional action, a constant adjusted difference in the speed of revolution between the outer and the inner drum. The control system can also effect by the alteration of the required coupled, a corrective controlling action alongside the proportional controlling action. A pulley coupled to the one drum acts as an electrical generating machine and the speed of revolution of the generator is converted by a tachogenerator into a signal for the proportional regulation of the speed of revolution. After comparison with the adjusted value of the difference in the number of revolutions, the signal provides a target value for the current from the generator and a signal parallel with the generator current is used for the correcting regulating action. The centrifuge is fitted with a cam disc reduction gear between the outer and the inner drum. The generator is coupled to the pulley of the reduction gear driving the inner drum, and means are provided so that when the number of revolutions of the inner drum falls below an adjusted value, a target value of the current from the generator is regulated proportionally or integrally from a signal parallel to the number of revolutions of the generator and a signal parallel to the current from the generator, in such a way that the generator brakes the pulley coupled to the inner drum. Device makes it possible to adjust the speeds of revolution of the inner and outer drum within close limits and maintain these constantly so that the product is as dry as possible. There is no pendulum swinging in the variation of the speeds.