US4025056A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mixing apparatus
Assignee: Imperial Chemical Industries Ltd
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Filing: 1975-06-30
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Granted: 1977-05-24
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Expires: 1995-06-30
Abstract
Abstract A gear pump comprising a driving and a driven gear, pairs of successive teeth of at least one gear each having a cut-out allowing a proportion of slip, the cut-outs each extending to the root of the tooth and the cut-outs in successive teeth being in axially differently located positions.
Inventors
- 👤 David Roy Miles
- 👤 Alun Woolcock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:01
CPC Classifications
F; F04; F04C; F04C2/00; F04C2/08; F04C2/082; F04C2/084; B; B01; B01F; B01F25/00; B01F25/60; B01F25/62; F04C13/00; F04C13/001; F04C13/002
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
179 words
In a gear pump having a housing forming a pump chamber having a curved wall and provided with at least one primary inlet port and at least one primary outlet port for the chamber, at least two intermeshing gears rotatably mounted in the chamber, each of said gears including teeth having front and rear sides and flat end faces and said gears cooperating with the curved wall of the chamber and with the ports to pump fluid from the inlet port to the outlet port, the improved construction which facilitates limited flow of fluid between consecutive tooth gaps when the associated teeth are in proximity to the curved wall of the pump chamber, said improved construction comprising an arrangement in which teeth of both gears have a passage extending from the root of the respective tooth on one side thereof toward the crest of that tooth to the other side of that tooth for permitting said flow between consecutive tooth gaps, the passages in successive teeth being in axially different positions with respect to the axes of the gears.
Claim 2
Dependent Claim
179 words
In a gear pump having a housing forming a pump chamber having a curved wall and provided with at least one primary inlet port and at least one primary outlet port for the chamber, at least two intermeshing gears rotatably mounted in the chamber, each of said gears including teeth having front and rear sides and flat end faces and said gears cooperating with the curved wall of the chamber and with the ports to pump fluid from the inlet port to the outlet port, the improved construction which facilitates limited flow of fluid between consecutive tooth gaps when the associated teeth are in proximity to the curved wall of the pump chamber, said improved construction comprising an arrangement in which teeth of both gears have a passage extending from the root of the respective tooth on one side thereof toward the crest of that tooth to the other side of that tooth for permitting said flow between consecutive tooth gaps, the passages in successive teeth being in axially different positions with respect to the axes of the gears.
Claim 3
Dependent Claim
26 words
A gear pump as in claim 1 in which the number of teeth in a gear having passage is even and every tooth has a passage.
Claim 4
Dependent Claim
33 words
A gear pump as in claim 1 wherein there is only one passage in each tooth having a passage and the passage is close to one of the flat faces of the gear.
Claim 5
Dependent Claim
21 words
A gear pump as in claim 1 wherein the passage comprises a duct passing from side to side of a tooth.
Claim 6
Dependent Claim
28 words
A gear pump as in claim 1 wherein the passage comprises a channel cut into the crown of a tooth and extending to the root of the tooth.
Claim 7
Dependent Claim
19 words
A gear pump as in claim 1 wherein the passage is formed in the flat face of the gear.
Claim 8
Dependent Claim
18 words
A gear pump as in claim 6 wherein the passage extends substantially to the crown of the tooth.
Claim 9
Dependent Claim
41 words
A gear pump according to claim 1 wherein the position and shape of the passage are such that flow through each passage is blocked by engagement of an intermeshing tooth with an end of the cut-out at the position of meshing.
Claim 10
Dependent Claim
25 words
A gear pump as in claim 1 wherein there are three gears one bearing no passages and intermeshing with each of two gears bearing passages.
Claim 11
Dependent Claim
53 words
A gear pump as in claim 1 wherein the pump housing includes a flat side plate adjacent the flat face of at least one of the gears, said plate having a secondary inlet port therein at a point swept at least in part by the teeth of at least one of the gears.
Claim 12
Dependent Claim
24 words
A gear pump as in claim 11 in which the secondary inlet port is entirely swept by the teeth of one of the gears.
Claim 13
Dependent Claim
30 words
A gear pump as in claim 11 wherein there are more than two intermeshing gears and wherein there is a secondary inlet port associated with each pair of meshing gears.
Claim 14
Dependent Claim
51 words
A gear pump as in claim 12 wherein each secondary inlet port is of such size and shape and so situated with respect to the gears that in operation one of the secondary ports is fully free from obstruction by a tooth when the other is fully closed by a tooth.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-23 | 1980-11-22 | 1981-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-23 | 1984-11-22 | 1985-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-23 | 1988-11-22 | 1989-05-24 | $7700.00 | Window Closed / Lapsed |