Method for in-situ restoration of platinum resistance thermometer calibration
A method is described for the in situ restoration of a platinum resistance thermometer, which has become decalibrated due to oxide surface film formation and/or strain-related damage, to a stress-free calibration condition wherein the thermometer includes a platinum resistor sensing element whose resistance varies with the temperature of the element in accordance with a known relationship. The method consists of: passing a controlled dc current through the platinum resistor sensing element, the current having a magnitude sufficient to raise the temperature of the element to its oxide decomposition and annealing temperature. The current is maintained for a heating period sufficient to restore the element to an oxide free surface and stress-free calibration condition.
- Assignee:
- Dept. of Energy, Washington, DC
- Patent Number(s):
- US 4795884
- OSTI ID:
- 6468478
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
47 OTHER INSTRUMENTATION
ANNEALING
CALIBRATION
CHALCOGENIDES
CHEMICAL REACTIONS
CORROSION
CURRENTS
DAMAGE
DECOMPOSITION
DEPOSITS
DESCALING
DIRECT CURRENT
ELECTRIC CURRENTS
ELECTRICAL EQUIPMENT
ELEMENTS
EQUIPMENT
HEAT TREATMENTS
MEASURING INSTRUMENTS
METALS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLATINUM
PLATINUM METALS
RESISTORS
SURFACE FINISHING
TEMPERATURE EFFECTS
TEMPERATURE MEASUREMENT
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
THERMOMETERS
TRANSITION ELEMENTS