LARGE RECORDING POTENTIOMETER ERROSRS CAUSED BY FURNACE LEAKAGE CURRENTS

Journal Article · Tue Nov 01 04:00:00 EST 1960 · Rev. Sci. Instr.

DOI:https://doi.org/10.1063/1.1716863· OSTI ID:4076717

Primak, W; Edwards, E

Large errors in the readings of recording and rec controlling potentiometers used with furnace thermic have been noted to be affected from plus or minus 600/sup o/C upward. An investigation showed that the lO% errors at 1000/sup o/C result of electrical conduction through the ceramic walls and the fused quartz thermocouple sheath. The temperature dependence of the effect corresponded to the tempperature dependence of the electrical resistivity of silica. It is evident that ceramics, as customarily employed, are not adequate for insulating thermocouples from furnace windings at high temperatures. Alternative solutions adequate to the present applications are (1) to suspend the thermocouple out of contact with the furnace walls which are at high temperatures, and (2) to provide a grounded metallic sheath between the furnace wall and the ceramic thermocouple sheath. (B.O.G.)

• Research Organization: Argonne National Lab., Ill.
• Sponsoring Organization: USDOE
• NSA Number: NSA-15-006185
• OSTI ID: 4076717
• Journal Information: Rev. Sci. Instr., Journal Name: Rev. Sci. Instr. Vol. Vol: 31
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

CERAMICS
COATING
CONTROL SYSTEMS
ELECTRIC CONDUCTIVITY
ELECTRIC INSULATION
ELECTRIC METERS
ENGINEERING AND EQUIPMENT
FURNACES
HIGH TEMPERATURE
METALS
QUARTZ
RECORDING SYSTEMS
SILICON OXIDES
THERMOCOUPLES