Patent US3691933A successfully refreshed from Google Patents.
US3691933A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic coffee brewer with liquid level sensor
Assignee: Bunn O Matic Corp
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Filing: 1971-07-06
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Granted: 1972-09-19
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Expires: 1991-07-06
Abstract
Abstract Cold water flows into a basin above a tank of hot water until a predetermined level is reached. A liquid level sensor then shuts off the flow of water into the basin and opens a valve to permit all of the water in the basin to flow into the tank from which the same quantity is siphoned out for brewing coffee.
Inventors
- 👤 John C Martin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:59
CPC Classifications
A; A47; A47J; A47J31/00; A47J31/44; A47J31/54; A47J31/56; A47J31/04; A47J31/057
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
139 words
Coffee brewing apparatus comprising a hot water tank, means for heating water in said tank, a siphon tube for withdrawing hot water from said tank to brew coffee extract, a cold water inlet pipe extending upwardly through said tank, a dump valve in said cold water inlet pipe, a cold water basin above said hot water tank connected to said cold water inlet pipe, an inlet water line interconnection said cold water basin and a source of cold water under pressure, a cold water supply valve in said inlet water line, means for closing said dump valve and opening said cold water supply valve to cause cold water to flow into said basin, and means for opening said dump valve and closing said cold water supply valve when a predetermined quantity of cold water has flowed into said basin.
Claim 2
Dependent Claim
139 words
Coffee brewing apparatus comprising a hot water tank, means for heating water in said tank, a siphon tube for withdrawing hot water from said tank to brew coffee extract, a cold water inlet pipe extending upwardly through said tank, a dump valve in said cold water inlet pipe, a cold water basin above said hot water tank connected to said cold water inlet pipe, an inlet water line interconnection said cold water basin and a source of cold water under pressure, a cold water supply valve in said inlet water line, means for closing said dump valve and opening said cold water supply valve to cause cold water to flow into said basin, and means for opening said dump valve and closing said cold water supply valve when a predetermined quantity of cold water has flowed into said basin.
Claim 3
Dependent Claim
25 words
Coffee brewing apparatus according to claim 1 wherein means substantially simultaneously close said dump valve and open said cold water supply valve and vice versa.
Claim 4
Dependent Claim
36 words
Coffee brewing apparatus according to claim 1 wherein a liquid level sensor is arranged to open said dump valve and close said cold water supply valve when the water in said basin reaches a predetermined level.
Claim 5
Dependent Claim
20 words
Coffee brewing apparatus according to claim 3 wherein said liquid level sensor includes a probe having an integral switching circuit.
Claim 6
Dependent Claim
54 words
Coffee brewing apparatus according to claim 3 wherein said liquid level sensor includes normally closed switch means controlled by a light responsive device, a light source and a prism for directing rays from said light source to said light responsive device as long as said prism is not contacted by water in said basin.
Claim 7
Dependent Claim
27 words
Coffee brewing apparatus according to claim 3 wherein a baffle encloses said liquid level sensor to permit the actual level of the liquid to be detected thereby.
Claim 8
Dependent Claim
35 words
Coffee brewing apparatus according to claim 3 wherein a baffle overlies the discharge end of said inlet water line to distribute the incoming cold water and prevent surges thereof to contact said liquid level sensor.
Claim 9
Dependent Claim
33 words
Coffee brewing apparatus according to claim 1 wherein said dump valve includes a section of flexible tubing forming a part of said cold water inlet pipe, and means for pinching said flexible tubing.
Claim 10
Dependent Claim
59 words
Coffee brewing apparatus according to claim 1 wherein a solenoid is arranged to operate said dump valve, another solenoid is arranged to operate said cold water supply valve, means are connected to energize said solenoids through normally closed circuit means, and means open said normally closed circuit means when the cold water in said basin reaches a predetermined level.
Claim 11
Dependent Claim
84 words
Coffee brewing apparatus according to claim 9 wherein said means for energizing said solenoids includes a relay having normally open contacts connected in series with said normally closed circuit means and an operating winding connected in parallel with said solenoids, a manually operable switch connects said winding and said solenoids for energization to a current source, and circuit means connect said contacts to said current source to provide a holding circuit for said winding and said solenoids when said manually operable switch is opened.
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) | 1975-09-19 | 1976-03-20 | 1976-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-19 | 1980-03-20 | 1980-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-19 | 1984-03-20 | 1984-09-19 | $7700.00 | Window Closed / Lapsed |