Patent ID: 6749402
Filing Date: 2004-06-15
Classification: B01F,F04B,G01F

Abstract:
A method of controlling a pump, the pump having a piston coupled to a motor, the method comprising:generating a dispense/intake profile for operation of the pump at varying motor speeds, the dispense/intake profile having a dispense portion and an intake portion, the profile being characterized as a plurality of value sets, each value set including angular position of the piston, flow rate and motor speed, the dispense portion of the profile having a peak dispense flow rate and the intake portion of the profile having a peak intake flow rate, the peak intake flow rate having an absolute value that is greater than the peak dispense flow rate as a result of a reduction in motor speed during the dispense portion of the profile as compared to the motor speed during the intake portion of the profile, dividing the profile into a plurality of steps wherein each step represents a transition from one value set to a succeeding value set so that each step represents one of a dispense amount that is less than an entire dispense amount of the dispense portion of the profile or an intake amount that is less than an entire intake amount of the intake portion of the profile, determining a number of steps required to dispense a desired amount of fluid; and operating the pump through the determined number of steps.