Continuous strip cold detector
AssigneeWalter Kidde & Company, Inc.
InventorsRaymond E. Belliveau, Simon J. Larkin
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Abstract
A continuous strip sensor for detecting extremely cold temperatures is disclosed. The sensor includes a plurality of series connected sections each of which exhibits a substantial increase in resistance upon exposure to an extremely cold temperature. A detection circuit utilizing the above sensor provides compensation for changes in ambient temperature by means of a compensation-sensor having the same total resistance and resistance-temperature characteristic as the cold sensor. The detection circuit also detects the occurrence of faults in the cold sensor or the compensation-sensor.
Claims9
A sensor for detecting cryogenic temperatures comprising a plurality of sensor sections electrically connected in series circuit relationship, each said section including:
- a first uninsulated electrically conductive wire;
- a second uninsulated electrically conductive wire;
- a plurality of thermistor beads electrically connected in parallel across said first and said second wires at substantially equal longitudinal intervals along said first and said second wires;
- each said bead having a resistance which increases with decreases in the temperature of said bead and each said bead being formed of a mixture comprising:
- manganese dioxide in the amount of 60-75% by weight,
- copper oxide in the amount of 15-25% by weight,
- a material selected from the group consisting of magnesium aluminum silicate, zircon and alumina in the amount of 5-20% by weight, and
- frit in the amount of 5-10% by weight.
Dependencies are inferred from the claim text.