Drive control circuit and the positive-displacement pump of positive displacement pump

摘要

PROBLEM TO BE SOLVED: To provide a displacement pump low in power consumption.;SOLUTION: In the displacement pump 1, a diaphragm 12 that varies the volume of a pump chamber 8 is mounted to the moving body 33 of an electromagnetic direct-operated actuator 3. A drive control circuit 70 includes an H bridge circuit 73, a constant current control circuit 76 and a power saving circuit 77. When reciprocating the moving body 33, the H bridge circuit 73 changes directions of an excitation current supplied to a drive coil 38 between the time of outward moving and the time of returning. In each time of outward moving and returning, the constant current control circuit 76 gradually decreases the excitation current from a time when starting the excitation of the drive coil 38, to a first excitation current I1, and to a second excitation current I2 which is lower than the first excitation current I1. The power saving circuit 77 reduces the excitation current from the second excitation current I2 to zero. Thus, power consumption is reduced compared to the case of continuously supplying a constant current to the drive coil 38 while the moving body 33 is reciprocated.;COPYRIGHT: (C)2012,JPO&INPIT