Liquid flow control device
US4987916A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 19, 1989 |
| Grant date | Jan 29, 1991 |
| Priority date | — |
| Expiry date | Jun 19, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/86743
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A liquid flow control device (20) comprises a variable orifice (28/30) in a conduit (15), and branch lines (41, 42) above and below a flow restriction, which may be the variable orifice itself. The orifice is controlled to maintain a predetermined relation between the pressures (P.sub.1, P.sub.2) in the two branches. A metering valve (60) for a second liquid to be injected into the conduit may be controlled simultaneously to maintain a preset ratio between the flow coefficients of the valve and the orifice, so that if the pressures above and below the metering valve are the same as the pressures above and below the variable orifice, the respective flow rates will stay in the same proportion, and the proportion of second liquid injected into the liquid in the conduit will be constant at all flow rates. The orifice control may be by piston and cylinder (50, 52) driven by the liquid pressures in the branch lines, the moving piston turning an orifice control rod (36) which also rotates a variable plug (62) in the metering valve. The specific application is for the injection of foam concentrate into a fire water distribution system, especially on an offshore oil platform, where flow rat…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.