Temperature-measurement errors with capsule-type resistance thermometers

2013 ◽  
Author(s):  
C. Gaiser ◽  
B. Fellmuth
Keyword(s):  
Temperature Measurement ◽  
Measurement Errors ◽  
Capsule Type ◽  
Resistance Thermometers

scholarly journals Correlation Between Insulation Resistance and Temperature Measurement Error in Type K and Type N Mineral Insulated, Metal Sheathed Thermocouples

2022 ◽  
Vol 43 (3) ◽  
Author(s):  
Jonathan Pearce ◽  
Declan Tucker ◽  
Carmen García Izquierdo ◽  
Raul Caballero ◽  
Trevor Ford ◽  
...  
Keyword(s):  
Temperature Measurement ◽  
Measurement Errors ◽  
Insulation Resistance ◽  
Monitoring And Control ◽  
Type K ◽  
Reference Type ◽  
Process Monitoring And Control ◽  
Resistance Breakdown ◽  
And Control

AbstractMineral insulated, metal sheathed (MI) Type K and Type N thermocouples are widely used in industry for process monitoring and control. One factor that limits their accuracy is the dramatic decrease in the insulation resistance at temperatures above about 600 °C which results in temperature measurement errors due to electrical shunting. In this work the insulation resistance of a cohort of representative MI thermocouples was characterised at temperatures up to 1160 °C, with simultaneous measurements of the error in indicated temperature by in situ comparison with a reference Type R thermocouple. Intriguingly, there appears to be a systematic relationship between the insulation resistance and the error in the indicated temperature. At a given temperature, as the insulation resistance decreases, there is a corresponding increasingly negative error in the temperature measurement. Although the measurements have a relatively large uncertainty (up to about 1 °C in temperature error and up to about 10 % in insulation resistance measurement), the trend is apparent at all temperatures above 600 °C, which suggests that it is real. Furthermore, the correlation disappears at temperatures below about 600 °C, which is consistent with the well-established diminution of insulation resistance breakdown effects below that temperature. This raises the intriguing possibility of using the as-new MI thermocouple calibration as an indicator of insulation resistance breakdown: large deviations of the electromotive force (emf) in the negative direction could indicate a correspondingly low insulation resistance.

The Selection of Thermistors for the Temperature Measurement Gear

1970 ◽  
Vol 111 (5) ◽  
pp. 59-62
Author(s):  
J. Leskauskaite ◽  
A. Dumcius
Keyword(s):  
Temperature Measurement ◽  
Measurement Errors ◽  
Numerical Data ◽  
Optimum Selection ◽  
Selection Of

The parameters represented on manufacturer datasheet are usually insufficient for the optimum selection of thermistors. Some manufacturers give generalized numerical data of R(T) dependences. Using this data it is possible to select successfully the most suitable thermistor and equation for describing of T(R) dependence. It is shown that by selecting four points in the generalized characteristic it is possible to calculate the coefficients of the approximation equation. By the application of these coefficients in the calculations the temperature measurement errors can be decreased by an order. The results of calculations and experiment are given. Ill. 4, bibl. 8, tabl. 5 (in English; abstracts in English and Lithuanian).http://dx.doi.org/10.5755/j01.eee.111.5.357

Transient Temperature Measurement Errors in Heated Slabs for Thermocouples Located at the Insulated Surface

1961 ◽  
Vol 83 (4) ◽  
pp. 505-506 ◽  
Author(s):  
D. R. Burnett
Keyword(s):  
Temperature Measurement ◽  
Measurement Errors ◽  
Wire Diameter ◽  
Temperature Measurements ◽  
Transient Temperature ◽  
Slab Thickness ◽  
Cold Side ◽  
Thermocouple Wire

A method is developed for estimating the error in “cold side” transient temperature measurements of slabs heated at one surface which is due to conduction of heat away from the junction through a thermocouple wire. Results are presented for a range of slab thickness/wire diameter ratios.

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