Patent US1645850A successfully refreshed from Google Patents.
US4468220A
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Low flow constant rate pump
Assignee: Milliken Research Corp
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Filing: 1982-04-05
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Granted: 1984-08-28
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Expires: 2002-04-05
Abstract
Abstract A low flow, constant rate pump is provided which comprises a fixed volume container, the inner walls of said container defining a receptacle for a liquid to be dispensed, said container being provided with means to form an unobstructed opening through which said liquid may be caused to flow continuously at a low-flow, constant rate, a propellant chamber within said container formed of a material which is permeable to vapor from a propellant of the liquid-vapor type, a supply of propellant of the liquid-vapor type confined within said chamber, said propellant initially being under pressure sufficient to maintain a major portion thereof in liquid form at normal temperatures.
Inventors
- 👤 Charles E. Willbanks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:58
CPC Classifications
A; A61; A61M; A61M31/00; A61M31/002; F; F16; F16N; F16N11/00; F16N11/10
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
141 words
A low flow, constant rate pump which comprises a fixed volume container, the inner walls of said container defining a receptacle for a liquid to be dispensed, said container being provided with means to form an unobstructed opening through which said liquid may be caused to flow continuously at a low-flow, constant rate, a propellant chamber within said container formed of a material which is permeable to vapor from a propellant of the liquid-vapor type, a supply of propellant of the liquid-vapor type confined within said chamber, said propellant initially being under pressure sufficient to maintain a major portion thereof in liquid form at normal temperatures, and wherein said propellant chamber within said container is itself encompassed by a flexible diaphragm impermeable to said propellant vapor and to said liquid to be dispensed, thereby separating said propellant vapor from said liquid.
Claim 2
Dependent Claim
141 words
A low flow, constant rate pump which comprises a fixed volume container, the inner walls of said container defining a receptacle for a liquid to be dispensed, said container being provided with means to form an unobstructed opening through which said liquid may be caused to flow continuously at a low-flow, constant rate, a propellant chamber within said container formed of a material which is permeable to vapor from a propellant of the liquid-vapor type, a supply of propellant of the liquid-vapor type confined within said chamber, said propellant initially being under pressure sufficient to maintain a major portion thereof in liquid form at normal temperatures, and wherein said propellant chamber within said container is itself encompassed by a flexible diaphragm impermeable to said propellant vapor and to said liquid to be dispensed, thereby separating said propellant vapor from said liquid.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-28 | 1988-02-27 | 1988-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-28 | 1992-02-27 | 1992-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-28 | 1996-02-27 | 1996-08-28 | $7700.00 | Window Closed / Lapsed |