Programmed valve system used for positioning control
US4276810A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1977 |
| Grant date | Jul 7, 1981 |
| Priority date | — |
| Expiry date | Oct 14, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/87177
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A programmed valve system for positioning control having a first two stage valve assembly operable for raising a load and a second two stage valve assembly for lowering the load. Each of the second stages has a poppet with a parabolic contour which is dimensioned with orifice parameters to provide substantially linear flow rate change for minimized shock when one of the second stage poppets closes and the other opens. In the raise assembly, the pilot stage outlet orifice has a cross-sectional area substantially larger than that of the inlet orifice so that the second stage poppet opens much more rapidly than the closing thereof thereby to minimize overshoot when the pilot stage is actuated to the open position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.