Constant pressure pump
US3985467A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 27, 1975 |
| Grant date | Oct 12, 1976 |
| Priority date | — |
| Expiry date | May 27, 1995 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF04B2205/05
- WIPO fieldControl
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.