US3716306A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gear pump construction
Assignee: Micropump Inc
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Filing: 1971-03-31
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Granted: 1973-02-13
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Expires: 1991-03-31
Abstract
Abstract A motor-driven gear pump used to pump fluid from a reservoir to a dispensing spigot has a cylinder connected to the pump discharge having a spring biased piston. The piston rod has a knob engaging a normally open microswitch controlling the motor. When the motor is running and the pump delivering through the spigot, the piston is in intermediate position and the knob maintains the switch closed. When the spigot is closed, back pressure builds up in the cylinder, forcing the piston to overcome the spring and the knob to move out of contact with the switch, stopping the motor. If the reservoir is empty, the cylinder empties and the spring moves the piston so that the knob moves out of contact with the switch, again stopping the motor as a safety precaution. Check valves are installed in the inlet line and discharge line of the pump. A manually actuated button moves the piston against the force of the spring and thus primes the pump and also closes the switch to start the motor.
Inventors
- 👤 T Martin
- 👤 D Londahl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:57
CPC Classifications
F; F04; F04C; F04C14/00; F04C14/06; F04C15/00; F04C15/0057; F04C15/0061; F04C15/0069
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
251 words
A pump comprising a housing having a pump chamber, an inlet and an outlet port for said pump chamber, an impeller in said pump chamber for pumping fluid from said inlet port through said pump chamber and out said outlet port at a higher pressure than at said inlet port, an inlet conduit connected to said inlet port, a first check valve in said inlet conduit, means establishing a source of supply of fluid for said pump connected to said inlet conduit, an outlet valve, an outlet conduit from said outlet port to said outlet valve, a second check valve in said outlet conduit, said housing also formed with a second chamber having at least one duct in one end of said second chamber, in fluid communication with said discharge port, a piston reciprocable in said second chamber, resilient means biasing said piston toward said one end against the pressure in said discharge port, manually operable means for moving said piston toward a second end opposite said one end to pump fluid from said source into said pump chamber to prime said pump chamber, a motor and drive means between said motor and said impeller, said piston having a rod extending externally of said housing and having a cam, a switch controlled by said cam controlling said motor, said cam operable to actuate said switch to stop said motor when the pressure in said discharge port overcomes tHe force of said resilient means and moves said piston to said second end.
Claim 2
Dependent Claim
251 words
A pump comprising a housing having a pump chamber, an inlet and an outlet port for said pump chamber, an impeller in said pump chamber for pumping fluid from said inlet port through said pump chamber and out said outlet port at a higher pressure than at said inlet port, an inlet conduit connected to said inlet port, a first check valve in said inlet conduit, means establishing a source of supply of fluid for said pump connected to said inlet conduit, an outlet valve, an outlet conduit from said outlet port to said outlet valve, a second check valve in said outlet conduit, said housing also formed with a second chamber having at least one duct in one end of said second chamber, in fluid communication with said discharge port, a piston reciprocable in said second chamber, resilient means biasing said piston toward said one end against the pressure in said discharge port, manually operable means for moving said piston toward a second end opposite said one end to pump fluid from said source into said pump chamber to prime said pump chamber, a motor and drive means between said motor and said impeller, said piston having a rod extending externally of said housing and having a cam, a switch controlled by said cam controlling said motor, said cam operable to actuate said switch to stop said motor when the pressure in said discharge port overcomes tHe force of said resilient means and moves said piston to said second end.
Claim 3
Dependent Claim
251 words
A pump comprising a housing having a pump chamber, an inlet and an outlet port for said pump chamber, an impeller in said pump chamber for pumping fluid from said inlet port through said pump chamber and out said outlet port at a higher pressure than at said inlet port, an inlet conduit connected to said inlet port, a first check valve in said inlet conduit, means establishing a source of supply of fluid for said pump connected to said inlet conduit, an outlet valve, an outlet conduit from said outlet port to said outlet valve, a second check valve in said outlet conduit, said housing also formed with a second chamber having at least one duct in one end of said second chamber, in fluid communication with said discharge port, a piston reciprocable in said second chamber, resilient means biasing said piston toward said one end against the pressure in said discharge port, manually operable means for moving said piston toward a second end opposite said one end to pump fluid from said source into said pump chamber to prime said pump chamber, a motor and drive means between said motor and said impeller, said piston having a rod extending externally of said housing and having a cam, a switch controlled by said cam controlling said motor, said cam operable to actuate said switch to stop said motor when the pressure in said discharge port overcomes tHe force of said resilient means and moves said piston to said second end.
Claim 4
Dependent Claim
251 words
A pump comprising a housing having a pump chamber, an inlet and an outlet port for said pump chamber, an impeller in said pump chamber for pumping fluid from said inlet port through said pump chamber and out said outlet port at a higher pressure than at said inlet port, an inlet conduit connected to said inlet port, a first check valve in said inlet conduit, means establishing a source of supply of fluid for said pump connected to said inlet conduit, an outlet valve, an outlet conduit from said outlet port to said outlet valve, a second check valve in said outlet conduit, said housing also formed with a second chamber having at least one duct in one end of said second chamber, in fluid communication with said discharge port, a piston reciprocable in said second chamber, resilient means biasing said piston toward said one end against the pressure in said discharge port, manually operable means for moving said piston toward a second end opposite said one end to pump fluid from said source into said pump chamber to prime said pump chamber, a motor and drive means between said motor and said impeller, said piston having a rod extending externally of said housing and having a cam, a switch controlled by said cam controlling said motor, said cam operable to actuate said switch to stop said motor when the pressure in said discharge port overcomes tHe force of said resilient means and moves said piston to said second end.
Claim 5
Dependent Claim
65 words
A pump according to claim 1 in which pressure in said discharge port balances said resilient means to hold said piston in an intermediate position between said one and said second ends, said piston being moved by said resilient means to said one end when said source is dry, said cam operable to actuate said switch to stop said motor when said source is dry.
Claim 6
Dependent Claim
40 words
A pump according to claim 2 in which said manually operable means simultaneously moves said piston from said one end to said intermediate position to prime said pump and moves said cam to actuate said switch to start said motor.
Claim 7
Dependent Claim
72 words
A pump according to claim 3 in which said first-mentioned rod is fixed to said piston and extends out through said second end of said second cylinder and in which said manually operable means comprises a second rod extending from the exterior of said housing through said one end of said cylinder to contact said piston, reciprocation of said second rod moving said piston from said one end to said intermediate position.
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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) | 1976-02-13 | 1976-08-14 | 1977-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-13 | 1980-08-14 | 1981-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-13 | 1984-08-14 | 1985-02-13 | $7700.00 | Window Closed / Lapsed |