CONTROL METHOD FOR NONPULSATING PUMP

PURPOSE:To make pressure pulsation reducible to the utmost by inputting the position and speed of a plunger as well as the detected value of a circuit and pressure in resultant discharge into a computer, and adding a motor driving frequency correction value to a driving pattern where the calculated speed sum of two plungers comes to be constant. CONSTITUTION:A microcomputer 24 calculates a constant showing that a speed command value is ideally realized to what degree by a difference in performance of hard itself on the basis of a speed detection signal 19 of a plunger. Next, such speed control that composite speed of both first and second plungers comes to be constant at all times is carried out by compensating a speed of the second plunger 9 mainly. In addition, a signal out of a pressure sensor 20 is converted into a correcting portion of the plunger speed, namely, a correction portion of pulse motor driving frequency in the computer 24, and then it is added to driving frequency of the plunger 9. Thus, speed control over the plunger is carried out by the computer 24 on the basis of both speed and pressure detecting signals of the plunger, whereby stable liquid conveyance with no pressure pulsation is made possible to be done.