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US 4,231,025 AGranted
Level and temperature readout and alarm system
AssigneeMetritape, Inc.
InventorJohn H. Turner, Jr.
Life of this patent
Estimating the term…
Abstract
For use with a resistance level and temperature sensor, operative to provide a measure of the level and temperature of a fluent material, a readout and alarm system operative to provide a numerical readout of material level and temperature as well as visual and audible indications of alarm conditions. The system is contained within a portable housing which can be employed in hostile environments and which can provide intrinsically safe operation in explosive atmospheres.
Claims13
For use with a resistance level and temperature sensor operative to provide a measure of the level and temperature of a fluent material, a readout and alarm system comprising:
- a first housing containing:
- an intrinsically safe first battery source for powering the circuits in the first housing:
- circuit means for excitation of said resistance level sensor and sensing of sensor signal representing fluent material level;
- circuit means for excitation of said resistance temperature sensor and sensing of sensor signal representing fluent material temperature;
- an analog-to-digital converter;
- switching means for selectively coupling the level sensor voltage or temperature sensor voltage to said converter;
- a digital display for visually indicating fluent material level or temperature as selected by said switching means;
- an alarm circuit for providing a level alarm signal upon sensing of a level sensor voltage which differs from a predetermined threshold;
- an alarm level indicator activated by said level alarm signal;
- a circuit for sensing low battery voltage of said first battery source and providing a low battery alarm signal;
- a low battery indicator activated by the low battery alarm signal of said first battery source;
- a circuit for sensing an open circuit condition and providing an open circuit alarm signal;
- an open circuit indicator activated by the open circuit alarm signal;
- a first terminal connected to said alarm circuit;
- a second terminal coupled to electrical ground;
- a third terminal connected to the first battery source;
- a second housing containing:
- an intrinsically safe second battery source for powering the circuits in the second housing;
- a circuit for sensing low battery voltage of said second battery source and providing a low battery alarm signal;
- a threshold circuit for providing an alarm threshold level;
- an audible alarm sounder;
- driver circuit means for said alarm sounder including means for causing said sounder to produce a first sound in response to an alarm signal above the alarm threshold level, and a second sound in response to said low battery alarm signal;
- a cable coupling said first, second and third terminals to respective fourth, fifth and sixth terminals of said second housing;
- the fourth terminal for coupling a received alarm signal to said threshold circuit;
- a fifth terminal coupled to electrical ground;
- and
- switch means operative to interconnect said fifth and sixth terminals and connect said battery source to electrical ground.
24 more elements
For use with a resistance level and temperature sensor operative to provide a measure of the level and temperature of a fluent material, a readout and alarm system having;
- a first housing containing excitation and sensing circuitry for the sensors and a numerical readout of material level and temperature, alarm circuitry for sensing of alarm conditions and alarm indicators for denoting respective alarm conditions, and a battery source for powering the circuits in the first housing;
- a second housing having an audible alarm sounder, driver circuit means for the alarm sounder, and a battery source for powering the circuits in the second housing;
- connector means comprising:
- a first cable on the first housing for coupling each sensor to the excitation and sensing circuitry and having redundant conductors for each sensor and terminating in a first electrical connector;
- second cable means having a second connector matable with the first connector and having a dual cable path providing dual redundant conductors for each sensor, each dual cable path terminating in a respective connector;
- a corresponding dual cable path having connectors matable with the connectors of the respective connectors of the second cable dual path and terminating in a single redundant cable path having a connector for coupling to an associated level and temperature sensor;
- the connectors of each dual path being matable with each other to isolate the associated cable from the environment when the system is not in use;
- and
- a cable interconnecting the circuitry of the first and second housings.
6 more elements
Dependencies are inferred from the claim text.