Method for vibrating the grid in a sieving machine has array of electromagnet transducers some driven by positive half cycle and some by negative half cycle of alternating supply

摘要

A method for vibrating the grid in a sieving machine has two sets of transducers fitted to the grid. The transducers are electromagnets driven by half cycles of an alternating supply. One set of transducers is driven by the positive half cycles and the other set is driven by the negative half cycles. The transducers are fitted to the sieve in alternate mountings. Another mounting has one type of transducer fitted to the inlet end of the sloping grid and the other type near to the outlet end. The transducers near to the inlet are driven with a larger amplitude than those near to the outlet. The overall effect of the two types of transducer is to lower the noise level by up to 6 dB.