Calibration and Application Techniques for Platinum Resistance Thermometers

1972 ◽  
Vol 94 (2) ◽  
pp. 381-386 ◽  
Author(s):  
R. P. Benedict ◽  
R. J. Russo

The International Practical Temperature Scale has been redefined recently. It follows that the interpolating equations relating platinum resistance to temperature must be reevaluated for all platinum resistance thermometers which are used as standards for calibration work. After a brief review of the former calibration procedure, the new temperature scale is discussed as it affects resistance thermometry in the temperature range from 0 C to 630.74 C. An example based on new experimental data is given to illustrate the method of determining thermometer constants for the new scale, and to indicate the magnitude of the changes required.

The technique is described of achieving the highest accuracy of measurement with platinum-resistance thermometers at the freezing point of zinc and the boiling point of sulphur. The two points are compared in a series of measurements and it is found that the zinc point is some three or four times more reproducible than the sulphur point. It is concluded that the substitution of the zinc point for the sulphur point as a primary fixed point of the International Temperature Scale would lead to a greater precision in the definition of the scale. The value of the freezing point of zinc is found to be 419∙5055 ± 0∙002°C.


1951 ◽  
Vol 29 (2) ◽  
pp. 142-150 ◽  
Author(s):  
J. M. Los ◽  
J. A. Morrison

A set of six platinum resistance thermometers of a form suitable for low temperature calorimetry has been made and calibrated in the region 11° to 90°K. by intercomparison with a similar thermometer which had been calibrated at the National Bureau of Standards. Above 90°K. calibration has been made on the International Temperature Scale.Using the intercomparison data, it has been possible to derive a method whereby for these thermometers the scale for the region 20° to 90°K. may be found to within 0.002°C. by means of fixed points. The method applies a 'Z function' of the type used at the National Bureau of Standards (13), plus a corrective term which depends upon the resistance of the thermometer at the boiling point of hydrogen and upon the normal constants which are determined for the International Temperature Scale above 90°K.


1962 ◽  
Vol 15 (3) ◽  
pp. 441
Author(s):  
RJ Berry ◽  
DR Lovejoy

In a recent paper on deviations from Matthiessen's rule for platinum Klemens and Lowenthal (1961) classified the deviation patterns, calculated for a number of different platinum resistance thermometers, into three groups, and reported that only one of these groups followed the pattern predicted by Sondheimer and Wilson's (1947) two-band conduction theory. They suggested that if resistors belonging to one particular group (though no matter which group) were selected for use in low temperature platinum resistance thermometry then the resistance-temperature relationship could be expressed accurately by a relatively simple formula. We believe that Klemens and Lowenthal's method of classifying the resistors into groups is open to serious objection and that consequently some of their important conclusions are not necessarily valid.


2020 ◽  
Vol 20 (2) ◽  
pp. 73-79
Author(s):  
Rudolf Palenčár ◽  
Stanislav Ďuriš ◽  
Jakub Palenčár ◽  
Martin Halaj ◽  
Ľubomír Šooš

AbstractThe paper presents a matrix approach to the propagation of uncertainties in the realization of the ITS-90 using Standard Platinum Resistance Thermometers (SPRT) calibrated at Defining Fixed Points (DFPs). The procedure allows correlations to be included between SPRT resistances measured during the calibration at the DFPs (i.e., the realization of the ITS-90) and the resistances measured during the subsequent use of the SPRT to measure temperature T90. The example also shows the possible contribution of these correlations to the overall temperature uncertainty measured by a calibrated SPRT.


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