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:
Oct. 12, 1976
Filed:
May. 27, 1975
Peter Lefferson, St. Petersburg, FL (US);
Milton Roy Company, St. Petersburg, FL (US);
Abstract
A controller maintains a constant desired fluid pressure in a fluid load driven by a variable flow fluid pump with a variable speed motor. A set point signal representing desired pressure and a signal from a pressure transducer representing actual pressure are applied to an error amplifier. The resulting error signal is applied through a variable gain stage to the motor control. The variable gain stage includes first and second variable gain amplifiers the first of which has a gain which is controlled inversely to pressure. The second variable gain amplifier has a gain which is controlled in proportion to flow. In this manner, the gain of the controller changes in inverse proportion to the restriction of the fluid load. This makes the performance of the controller independent of changes in the fluid load by keeping the total loop gain constant.