Patent US3740740A successfully refreshed from Google Patents.
US3740740A
Expired / Lapsed
US
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Liquid cryogen detector
Assignee: United States Department of the Army
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Filing: 1972-01-12
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Granted: 1973-06-19
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Expires: 1992-01-12
Abstract
Abstract A carbon composition resistor sensor is lowered to a cryogen material which is in its cryogenic state. The current through the sensor is maintained constant by a regulator, and when a sustantial change in the resistance of the carbon sensor occurs, an amplifier having its input connected across the regulator senses the change in the resistance of the regulator and causes a light to go on or off so as to indicate the top level of the cryogenic material.
Inventors
- 👤 W Milo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:08
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/24; G01F23/246; G01F23/247
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
212 words
A cryogen level detector comprising a resistor; means for causing said resistor to go into and out of said cryogen material whereby said resistor will correspondly sharply change its resistance from a low state to a high state; sensing means connected to said resistor to sense its state; an indicator connected to the output of the sensing means so as to indicate the state of said resistor; said sensing means comprise a power source; a current regulator; and an amplifier having inputs and outputs; said power source, current regulator and resistor being connected in a series circuit whereby a constant current will flow through this circuit; said amplifier having its input connected across said current regulator so as to sense the voltage thereacross; the output of said amplifier being connected to said indicating means; said low state of said resistor is a cryogenic state and said high state is not a cryogenic state; said indicating means is a light means which will go on when said resistor is in a cryogenic state and will be off when said resistor is not in a cryogenic state; said resistor being moveably mounted with respect to said cryogen; and scale means connected to said moveable means so as to indicate the height of said resistor.
Claim 2
Dependent Claim
212 words
A cryogen level detector comprising a resistor; means for causing said resistor to go into and out of said cryogen material whereby said resistor will correspondly sharply change its resistance from a low state to a high state; sensing means connected to said resistor to sense its state; an indicator connected to the output of the sensing means so as to indicate the state of said resistor; said sensing means comprise a power source; a current regulator; and an amplifier having inputs and outputs; said power source, current regulator and resistor being connected in a series circuit whereby a constant current will flow through this circuit; said amplifier having its input connected across said current regulator so as to sense the voltage thereacross; the output of said amplifier being connected to said indicating means; said low state of said resistor is a cryogenic state and said high state is not a cryogenic state; said indicating means is a light means which will go on when said resistor is in a cryogenic state and will be off when said resistor is not in a cryogenic state; said resistor being moveably mounted with respect to said cryogen; and scale means connected to said moveable means so as to indicate the height of said resistor.
References Cited (Backward Citations)
US3267730A
Cited
FR1391944A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |