Calibrated isothermal assembly for a thermocouple thermometer
AssigneeFluke Corporation
InventorsJohn M. Lund, Jonathan J. Parle, Monte R. Washburn
Life of this patent
Estimating the term…
Abstract
A calibrated isothermal assembly for a thermocouple thermometer is provided to obviate a calibration step after manufacture of the instrument. A compact isothermal block is fabricated on a specialized printed circuit board which includes a thick metal plate to establish sufficient thermal mass and good heat conductivity. A temperature sensor is mounted at the thermocouple reference junction on the printed circuit board to track the reference junction temperature. The calibrated isothermal assembly also includes a current source for the temperature sensor, and a memory device containing stored calibration data specific to the temperature sensor.
Claims11
A calibrated isothermal assembly for a thermocouple thermometer, comprising:
- a base member comprising a metal plate having a high heat conductivity characteristic and sufficient thermal mass to provide an isothermal block, said metal plate having an electrical insulative layer disposed thereon;
- a pair of electrical contacts disposed on said electrical insulative layer and forming a virtual reference junction for a thermocouple;
- a temperature sensing transistor having a voltage-temperature characteristic curve mounted on said base member proximate said pair of electrical contacts;
- and
- a memory device mounted on said base member, said memory device containing calibration data relating to said voltage-temperature characteristic curve of said temperature sensing transistor.
A compact isothermal assembly, comprising:
- a metal plate upon which is disposed at least one electrical insulative layer to form a specialized printed circuit board, said metal plate having sufficient thermal mass to provide an isothermal block;
- a pair of conductive pads disposed in juxtaposition on a surface of said at least one electrical insulative layer;
- a temperature sensing transistor having a voltage-temperature characteristic curve disposed on said surface in close proximity to said conductive pads;
- a memory device disposed on a surface of said at least one insulative layer, said memory device containing calibration data relating to said voltage-temperature characteristic curve of said temperature sensing transistor.
Dependencies are inferred from the claim text.