US4597719A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Suck-back pump
Assignee: Canon Inc
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Filing: 1984-03-26
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Granted: 1986-07-01
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Expires: 2004-03-26
Abstract
Abstract A suck-back pump for preventing any additional amount of liquid from dropping out of the tip of a delivery pipe, after a predetermined amount of liquid has been delivered from the delivery pipe. The suck-back pump includes inlet and outlet ports for liquid, first and second chamber respectively connected with the inlet and outlet ports, a communicating passage for connecting the first and second chambers with each other, a shut-off valve movable to close the communicating passage, and a suction element movable to change the volume of the second chamber. The actuation of the suction element is retarded so that it is actuated after the shut-off valve has been actuated.
Inventors
- 👤 Terukuni Tano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:57
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/16; G01; G01F; G01F15/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
220 words
A suck-back pump for preventing any additional amount of liquid from dropping out of an outlet of a delivery pipe, by drawing the liquid within the delivery pipe, said suck-back pump comprising: an inlet port for receiving liquid; an outlet port to be placed in communication with said delivery pipe; a first chamber communicating with said inlet port; a second chamber communicating with said outlet port; a flow passage for connecting said first chamber with said second chamber; a shut-off valve for opening and closing said flow passage; suction means for changing the volume of said second chamber; a first piston for moving said shut-off valve; a second piston for moving said suction means; a first cylinder slidably receiving said shut-off valve moving piston; a second cylinder slidably receiving said suction means moving piston; a first flow passage for supplying pressurized fluid to said first cylinder for said shut-off valve moving piston to move the piston therein, and a second flow passage for connecting said first cylinder for said shut-off valve moving piston with said second cylinder for said suction means moving piston for supplying pressurized fluid from the former to the latter, said second flow passage being constructed to connect said first and second cylinders with each other when said shut-off valve moving piston moves through a predetermined distance.
Claim 2
Dependent Claim
220 words
A suck-back pump for preventing any additional amount of liquid from dropping out of an outlet of a delivery pipe, by drawing the liquid within the delivery pipe, said suck-back pump comprising: an inlet port for receiving liquid; an outlet port to be placed in communication with said delivery pipe; a first chamber communicating with said inlet port; a second chamber communicating with said outlet port; a flow passage for connecting said first chamber with said second chamber; a shut-off valve for opening and closing said flow passage; suction means for changing the volume of said second chamber; a first piston for moving said shut-off valve; a second piston for moving said suction means; a first cylinder slidably receiving said shut-off valve moving piston; a second cylinder slidably receiving said suction means moving piston; a first flow passage for supplying pressurized fluid to said first cylinder for said shut-off valve moving piston to move the piston therein, and a second flow passage for connecting said first cylinder for said shut-off valve moving piston with said second cylinder for said suction means moving piston for supplying pressurized fluid from the former to the latter, said second flow passage being constructed to connect said first and second cylinders with each other when said shut-off valve moving piston moves through a predetermined distance.
Claim 3
Dependent Claim
24 words
A suck-back pump as defined in claim 1, further comprising a needle valve disposed in said second flow passage for selectively connecting said cylinders.
Claim 4
Dependent Claim
40 words
A suck-back pump as defined in claim 1, further comprising means for retarding the actuation of said suction means relative to that of said shut-off valve such that said suction means is actuated after said shut-off valve has been actuated.
Claim 5
Dependent Claim
18 words
A suck-back pump as defined in claim 3, further comprising selection means for selectively actuating said retarding means.
Claim 6
Dependent Claim
59 words
A suck-back pump as defined in claim 4, wherein said selection means comprises a needle valve located within said second flow passage and the operation of said suction means moving piston is adjusted by adjusting said needle valve to control the flow of the pressurized fluid to be supplied to said second cylinder for said suction means moving piston.
Claim 7
Dependent Claim
40 words
A suck-back pump as defined in claim 1, further comprising a third flow passage for connecting said first and second cylinders with each other to discharge the pressurized fluid out of said second cylinder for said suction means moving piston.
Claim 8
Dependent Claim
50 words
A suck-back pump as defined in claim 6, further comprising check valve means provided between said first cylinder for said shut-off valve moving piston and said third flow passage for preventing reverse flow of fluid from said first cylinder for said shut-off valve moving piston to said third flow passage.
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) | 1989-06-30 | 1989-12-30 | 1990-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-30 | 1993-12-30 | 1994-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-30 | 1997-12-30 | 1998-07-01 | $7700.00 | Window Closed / Lapsed |