Patent US4538960A successfully refreshed from Google Patents.
US4538960A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Axial thrust balancing device for pumps
Assignee: Hitachi Ltd
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Filing: 1981-02-13
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Granted: 1985-09-03
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Expires: 2001-02-13
Abstract
Abstract This invention relates to an axial thrust balancing device for pumps which cancels an axial thrust caused by impellers by utilizing a discharge water pressure. In the device, there is provided a small axial gap between a low pressure sidewall of a balancing drum tightly fitted over a shaft of impellers and a flange-like end wall extending inwardly from a stationary wall along the low pressure sidewall of said balancing drum. On application of the device to a vertical pump, in particular, the balancing drum is prevented from being in contact with the end wall during suspension of operation.
Inventors
- 👤 Toshiki Iino
- 👤 Kunio Kamata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 06:05
CPC Classifications
F; F01; F01D; F01D3/00; F01D3/04; F04; F04D; F04D29/00; F04D29/04; F04D29/041; F04D29/0416
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
173 words
An axial thrust balancing device for pumps, the thrust balancing device comprising: a balancing drum secured to a shaft of impellers at a side of a last stage of said impellers for rotation therewith; a stationary wall having a flange-like end wall portion extending inwardly along a low pressure sidewall of said balancing drum; a small annular gap defined between said balancing drum and said stationary wall; a small annular axial gap defined between the low pressure sidewall of said balancing drum and the end wall portion of the stationary wall at a small radius position; a high pressure chamber defined by the last stage of said impellers, said stationary wall and the high pressure side wall of said balancing drum; an intermediate pressure chamber defined between said annular gap and said axial gap by said flange-like end wall portion of said stationary wall and the low pressure sidewall of said balancing drum; and a low pressure chamber defined at a rear side of said flange-like end wall portion of said stationary wall.
Claim 2
Dependent Claim
173 words
An axial thrust balancing device for pumps, the thrust balancing device comprising: a balancing drum secured to a shaft of impellers at a side of a last stage of said impellers for rotation therewith; a stationary wall having a flange-like end wall portion extending inwardly along a low pressure sidewall of said balancing drum; a small annular gap defined between said balancing drum and said stationary wall; a small annular axial gap defined between the low pressure sidewall of said balancing drum and the end wall portion of the stationary wall at a small radius position; a high pressure chamber defined by the last stage of said impellers, said stationary wall and the high pressure side wall of said balancing drum; an intermediate pressure chamber defined between said annular gap and said axial gap by said flange-like end wall portion of said stationary wall and the low pressure sidewall of said balancing drum; and a low pressure chamber defined at a rear side of said flange-like end wall portion of said stationary wall.
Claim 3
Dependent Claim
58 words
An axial thrust balancing device according to claim 1, wherein said pump is a vertical pump including a rotary shaft with a bearing means adapted for rotatably supporting the shaft in a vertical direction, a casing means for supporting said bearing, and a projection means extending from said casing for limiting a downward movement of said bearing means.
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) | 1988-09-02 | 1989-03-04 | 1989-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-02 | 1993-03-04 | 1993-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-02 | 1997-03-04 | 1997-09-03 | $7700.00 | Window Closed / Lapsed |