The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 23, 1997
Filed:
Mar. 22, 1995
Keith E Chipperfield, Vancouver, WA (US);
Kevin O'Hara, Vancouver, WA (US);
Greg Kangiser, Vancouver, WA (US);
Steve Soar, Vancouver, WA (US);
Micropump, Inc., Vancouver, WA (US);
Abstract
A pump motor controller for making pump motor speed independent of fluid pressure at the inlet and outlet of the pump. A first embodiment employs feedback to cause pump motor speed to converge to a desired speed established with a reference input signal. Based on this feedback, forward and reverse drive amplifiers in the first embodiment cause the pump motor speed to track the desired speed. A second embodiment employs a controller that produces drive signals to a stepper motor in proportion to a reference frequency. The controller and stepper motor in the second embodiment achieve speed control at low speeds without the use of a feedback control loop.