US3635581A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-pressure centrifugal pump
Assignee: AIRCRYO Inc A CA CORP
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Filing: 1969-08-22
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Granted: 1972-01-18
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Expires: 1989-08-22
Abstract
Abstract This centrifugal pump for high-pressure service has novel sealing means for preventing the fluid being pumped from reaching the bearings of the impeller shaft. The back of the impeller on the side opposite the pumping vanes has shallow vanes that run close to a confronting face of the pump housing for displacing leakage fluid back to the pump inlet. Leakage is maintained at a low value by a generally cylindrical portion on the back of the impeller running with close running clearance in a plastic sleeve in the backwall of the pump housing. The impeller shaft bearings are in a gear housing secured to the pump and have their own means of lubrication.
Inventors
- 👤 Kenneth E Nichols
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:41
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/08; F04D29/10; F04D29/12; F04D29/126; F04D13/00; F04D13/02; F05; F05B; F05B2240/00; F05B2240/70
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
227 words
A centrifugal pump including a pump housing enclosing a pumping chamber, an impeller in the pumping chamber, an inlet passage through which fluid flows to the impeller in the pumping chamber, the impeller having a body portion with axially spaced front and back surfaces, vanes extending from the front surface across the pumping chamber and smaller vanes on the back surface, a shaft for driving the impeller, a backplate of the pump housing providing a backwall through which the shaft extends, said backwall having an annular surface close to the vanes on the back surface whereby said vanes on the back surface displace fluid outward away from the shaft, bearing means for the shaft rearward of the impeller, the body portion of the impeller extending radially beyond the vanes on the back surface, and a portion of the back surface beyond the back surface vanes having a close running clearance with the backwall to reduce leakage of fluid between the impeller and the backwall toward the shaft, a recess in the backplate between the back surface vanes and said close running clearance into which fluid is displaced by the back surface vanes, passage means through which fluid flows out of said recess, said passage means communicating with said inlet passage whereby fluid which leaks between the impeller and the backwall is fed back to the inlet passage.
Claim 2
Dependent Claim
227 words
A centrifugal pump including a pump housing enclosing a pumping chamber, an impeller in the pumping chamber, an inlet passage through which fluid flows to the impeller in the pumping chamber, the impeller having a body portion with axially spaced front and back surfaces, vanes extending from the front surface across the pumping chamber and smaller vanes on the back surface, a shaft for driving the impeller, a backplate of the pump housing providing a backwall through which the shaft extends, said backwall having an annular surface close to the vanes on the back surface whereby said vanes on the back surface displace fluid outward away from the shaft, bearing means for the shaft rearward of the impeller, the body portion of the impeller extending radially beyond the vanes on the back surface, and a portion of the back surface beyond the back surface vanes having a close running clearance with the backwall to reduce leakage of fluid between the impeller and the backwall toward the shaft, a recess in the backplate between the back surface vanes and said close running clearance into which fluid is displaced by the back surface vanes, passage means through which fluid flows out of said recess, said passage means communicating with said inlet passage whereby fluid which leaks between the impeller and the backwall is fed back to the inlet passage.
Claim 3
Dependent Claim
105 words
The centrifugal pump described in claim 1 characterized by the recesS in the backplate being annular and confronting the back surface of the impeller, another annular recess in a peripheral surface of the backplate and radially outward from the first annular recess, a cylindrical portion of the housing surrounding the periphery of the backplate and closing the peripheral surface recess in the backplate, said passage means including angularly spaced passages connecting said recesses and a passage in the housing communicating with the peripheral recess and extending within a wall of the housing and opening at said inlet passage through which fluid flows to the impeller.
Claim 4
Dependent Claim
48 words
The centrifugal pump described in claim 1 characterized by a gear box into which the shaft extends and in which the bearing means are located, gearing in the gear box for driving the impeller drive shaft, and common means for lubricating the shaft bearing means and said gearing.
Claim 5
Dependent Claim
103 words
The centrifugal pump described in claim 3 characterized by the bearing means for the impeller shaft being carried by parts of the pump housing including a part that fits into the gear box, detachable fastening means holding the pump in assembled relation with the gear box, a power shaft extending into the gear box, said gearing for driving the impeller drive shaft including a bevel gear secured to the power shaft in the gear box, a bevel gear on the impeller shaft in position to mesh with the bevel gear on the power shaft when the pump is fastened to the gear box.
Claim 6
Dependent Claim
77 words
The centrifugal pump as described in claim 1 characterized by a cylindrical surface of the backwall surrounding a generally cylindrical portion of the back surface of the impeller, said cylindrical surface comprising a smooth plastic sleeve inserted into a recess in said backwall, and threads on the generally cylindrical portion of the back surface of the impeller with the diameters of the tops of the threads substantially equal to the inside diameter of the smooth plastic sleeve.
Claim 7
Dependent Claim
220 words
A centrifugal pump including a pump housing enclosing a pumping chamber, an impeller in the pumping chamber, the impeller having a body portion with axially spaced front and radially back surfaces, vanes extending from the front surface across the pumping chamber and smaller vanes on the back surface, a shaft for driving the impeller, a backplate of the pump housing providing a backwall through which the shaft extends, said backwall having an annular surface close to the vanes on the back surface whereby said vanes on the back surface displace fluid outward away from the shaft, bearing means for the shaft rearward of the impeller, the body portion of the impeller extending radially beyond the vanes on the back surface and a portion of the back surface beyond the back surface vanes having a close running clearance with the backwall to reduce leakage of fluid inward along the back of the impeller, a generally cylindrical portion of the back surface of the impeller coaxial with the axis of rotation of the impeller, a complementary surface on the backwall close to the generally cylindrical portion of the back surface of the impeller, at least a portion of said close running clearance being between said generally cylindrical portion of the back surface of the impeller and the cylindrical surface of the backwall.
Claim 8
Dependent Claim
220 words
A centrifugal pump including a pump housing enclosing a pumping chamber, an impeller in the pumping chamber, the impeller having a body portion with axially spaced front and radially back surfaces, vanes extending from the front surface across the pumping chamber and smaller vanes on the back surface, a shaft for driving the impeller, a backplate of the pump housing providing a backwall through which the shaft extends, said backwall having an annular surface close to the vanes on the back surface whereby said vanes on the back surface displace fluid outward away from the shaft, bearing means for the shaft rearward of the impeller, the body portion of the impeller extending radially beyond the vanes on the back surface and a portion of the back surface beyond the back surface vanes having a close running clearance with the backwall to reduce leakage of fluid inward along the back of the impeller, a generally cylindrical portion of the back surface of the impeller coaxial with the axis of rotation of the impeller, a complementary surface on the backwall close to the generally cylindrical portion of the back surface of the impeller, at least a portion of said close running clearance being between said generally cylindrical portion of the back surface of the impeller and the cylindrical surface of the backwall.
Claim 9
Dependent Claim
74 words
The centrifugal pump described in claim 6 characterized by the cylindrical surface of the backwall surrounding the generally cylindrical portion of the back surface of the impeller and comprising a smooth plastic sleeve inserted into a recess in said backwall, and threads on the generally cylindrical portion of the back surface of the impeller with the diameters of the tops of the threads substantially equal to he inside diameter of the smooth plastic sleeve.
Claim 10
Dependent Claim
17 words
The centrifugal pump described in claim 6 characterized by the smooth plastic sleeve being made of polytetrafluoroethylene.
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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) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |