Patent US4841967A successfully refreshed from Google Patents.
Patent US3796508A successfully refreshed from Google Patents.
US3796508A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Screwpumps
Assignee: Simon Hartley Ltd
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Filing: 1972-05-05
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Granted: 1974-03-12
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Expires: 1992-05-05
Abstract
Abstract A screw pump of the kind comprising a screw of the archimedean type which is adapted to be rotated in an inclined trough to pump a liquid up the trough characterised in that the screw is comprised by at least two separate co-axial screw portions each having helical flights and mounted on a common central shaft, the screw portions being disposed in an inclined trough having a plurality of separate portions of complementary cross-section, there being an inlet for liquid to be pumped at the lower end of each said trough portion, and an outlet for pumped liquid at the upper end of at least the uppermost portion.
Inventors
- 👤 R Rowley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:49
CPC Classifications
F; F04; F04D; F04D3/00; F04D3/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
93 words
A screw pump comprising a screw of the Archimedean type, an inclined trough in which said screw is located, drive means for rotating said screw in said trough, an inlet at the lower end of said trough for receiving liquid to be pumped, an outlet at the upper end of said trough for dispensing pumped liquid, and a further inlet in said trough at an intermediate level part way between said first mentioned inlet and said outlet for receiving further liquid to be pumped from said level towards said outlet by said screw.
Claim 2
Dependent Claim
93 words
A screw pump comprising a screw of the Archimedean type, an inclined trough in which said screw is located, drive means for rotating said screw in said trough, an inlet at the lower end of said trough for receiving liquid to be pumped, an outlet at the upper end of said trough for dispensing pumped liquid, and a further inlet in said trough at an intermediate level part way between said first mentioned inlet and said outlet for receiving further liquid to be pumped from said level towards said outlet by said screw.
Claim 3
Dependent Claim
47 words
A screw pump according to claim 1, characterised in that said screw consists essentially of two co-axial axially separate screw portions each having helical flights and mounted on a common central shaft, and said intermediate level input is located at the bottom of the upper screw portion.
Claim 4
Dependent Claim
37 words
A screw pump according to claim 2, wherein said common central shaft is mounted for rotation in bearings adjacent its extreme upper and lower ends respectively and is driven by a motor connected with said upper end.
Claim 5
Dependent Claim
30 words
A screw pump according to claim 2, wherein said screw portions are of different effective diameter and said trough has separate portions of corresponding size associated with said screw portions.
Claim 6
Dependent Claim
22 words
A screw pump according to claim 4, wherein the lower of said screw portions is of smaller effective diameter than the upper.
Claim 7
Dependent Claim
144 words
A screw pump of the kind comprising a screw of the archimedean type which is adapted to be rotated in an inclined trough to pump a liquid up the trough characterised in that the screw is comprised by at least two separate axially spaced apart co-axial screw portions each having helical flights and mounted on a common central shaft, the screw portions being disposed in an inclined trough having a plurality of separate portions of complementary cross-section, there being an inlet for liquid to be pumped at the lower end of each said trough portion, an outlet for pumpEd liquid at the upper end of at least the uppermost portion, and a sealing disc secured to said shaft at the lower end of an upper screw portion thus to close the cross-section of the screw at said lower end of said upper screw portion.
Claim 8
Dependent Claim
144 words
A screw pump of the kind comprising a screw of the archimedean type which is adapted to be rotated in an inclined trough to pump a liquid up the trough characterised in that the screw is comprised by at least two separate axially spaced apart co-axial screw portions each having helical flights and mounted on a common central shaft, the screw portions being disposed in an inclined trough having a plurality of separate portions of complementary cross-section, there being an inlet for liquid to be pumped at the lower end of each said trough portion, an outlet for pumpEd liquid at the upper end of at least the uppermost portion, and a sealing disc secured to said shaft at the lower end of an upper screw portion thus to close the cross-section of the screw at said lower end of said upper screw portion.
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) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |