Zero pulsation pump
OwnerRichard HEMBREEinventor
Life of this patent
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Abstract
A positive displacement pump includes at least two pumping chambers and associated plungers. Each plunger is driven by an associated variable speed motor, such as a stepper motor, in a reciprocating motion. The stepper motor varies speed during each stroke of the plunger. A controller controls speed and direction of each stepper motor. Each stepper motor is coupled to a leadscrew having an associated guide rod mounted on the leadscrew to move along the leadscrew as the leadscrew rotates and actuate an associated plunger. The controller varies the speed, displacement and duration of the stepper motors' steps to maintain a constant outflow without pulses.
Claims18
A positive displacement pump, comprising:
- a plurality of pumping chambers;
- a plunger associated with each pumping chamber, each of the plungers moving in a reciprocating motion;
- a variable speed motor driving each plunger, the variable speed motor varying speed during each stroke;
- and
- a controller controlling speed and direction of each variable speed motor.
A method for controlling a pump, the pump having a first pumping chambers and an associated first plunger, and a second pumping chamber and an associated second plunger, each plunger being driven by an associated variable speed motor, and a controller;
- the method comprising:
- controllably driving a first variable speed motor to vary displacement and speed of the associated first plunger;
- controllably driving a second variable speed motor to vary displacement and speed of the associated second plunger;
- the speed of displacement of each variable speed motor being varied as the plungers approach top dead center and bottom dead center and coordinated so that pump outflow is substantially constant.
Dependencies are inferred from the claim text.