THE FREEZING POINTS OF HIGH PURITY METALS AS PRECISION TEMPERATURE STANDARDS: I. PRECISION MEASUREMENTS WITH STANDARD RESISTANCE THERMOMETERS

1957 ◽  
Vol 35 (1) ◽  
pp. 78-90 ◽  
Author(s):  
E. H. McLaren
Keyword(s):  
Triple Point ◽  
Cold Work ◽  
Platinum Resistance ◽  
Intrinsic Resistance ◽  
Long Term Stability ◽  
Resistance Bridge ◽  
Platinum Resistance Thermometers ◽  
Resistance Thermometers ◽  
Precision Temperature

The techniques and difficulties encountered in measuring temperatures to the highest precision with platinum resistance thermometers are discussed. It is shown that the relative drift of the resistance coils in the Mueller resistance bridge used for these measurements is less than a part per million per year. The intrinsic resistance of a platinum thermometer is comparatively unstable, and results showing some effects of cold work and heat treatment on several thermometers are given.As each precision temperature determination involves the resistance of the thermometer at the triple point of water, extensive measurements have been carried out to obtain information on: (a) the reproducibility of temperature in particular cells, (b) the variation in temperature among cells, and (c) the long term stability of cell temperatures.The limiting uncertainties in temperature measurements due to variation in the bridge, the thermometers, and the triple point cells are each of the order of 10−4 °C.

scholarly journals A Software Improvement Technique for Platinum Resistance Thermometers

Instruments ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 15 ◽  
Author(s):  
Andrew Chen ◽  
Hsuan-Yu Chen ◽  
Chiachung Chen
Keyword(s):  
High Sensitivity ◽  
Microprocessor System ◽  
Platinum Resistance ◽  
Long Term Stability ◽  
Accuracy And Precision ◽  
Platinum Resistance Thermometers ◽  
Resistance Thermometers ◽  
Temperature Ranges ◽  
The Difference ◽  
Calibration Equations

Temperature measurement is essential in industries. The advantages of resistance temperature detectors (RTDs) are high sensitivity, repeatability, and long-term stability. The measurement performance of this thermometer is of concern. The connection between RTDs and a novel microprocessor system provides a new method to improve the performance of RTDs. In this study, the adequate piecewise sections and the order of polynomial calibration equations were evaluated. Systematic errors were found when the relationship between temperature and resistance for PT-1000 data was expressed using the inverse Callendar-Van Dusen equation. The accuracy of these calibration equations can be improved significantly with two piecewise equations in different temperature ranges. Two datasets of the resistance of PT-1000 sensors in the range from 0 °C to 50 °C were measured. The first dataset was used to establish adequate calibration equations with regression analysis. In the second dataset, the prediction temperatures were calculated by these previously established calibration equations. The difference between prediction temperatures and the standard temperature was used as a criterion to evaluate the prediction performance. The accuracy and precision of PT-1000 sensors could be improved significantly with adequate calibration equations. The accuracy and precision were 0.027 °C and 0.126 °C, respectively. The technique developed in this study could be used for other RTD sensors and/or different temperature ranges.

RADIATION EFFECTS IN PRECISION RESISTANCE THERMOMETRY: II. ILLUMINATION EFFECT ON TEMPERATURE MEASUREMENT IN WATER TRIPLE-POINT CELLS PACKED IN CRUSHED ICE

1966 ◽  
Vol 44 (11) ◽  
pp. 2653-2659 ◽  
Author(s):  
E. H. McLaren ◽  
E. G. Murdock
Keyword(s):  
Triple Point ◽  
Radiation Effects ◽  
Near Infrared ◽  
Radiation Shielding ◽  
Platinum Resistance ◽  
Platinum Resistance Thermometers ◽  
Resistance Thermometers ◽  
Temperature Errors ◽  
Crushed Ice ◽  
Water Triple Point

The heating effect of normal laboratory illumination on the sensors of standard platinum resistance thermometers immersed in a standard water triple-point cell packed in crushed ice has been investigated. This study shows that the absorption by the platinum sensors of luminous and near-infrared radiation transmitted through the ice pack could easily amount to temperature errors as large as 0.000 5 °C. Any illumination error must be eliminated by making all measurements in the dark or under adequate radiation shielding.

Certifying precision platinum resistance thermometers

1990 ◽  
Vol 33 (6) ◽  
pp. 586-588
Author(s):  
S. L. Knina ◽  
A. A. Nechai ◽  
A. A. Semenov ◽  
V. A. Petrushina ◽  
A. I. Pokhodun
Keyword(s):  
Platinum Resistance ◽  
Platinum Resistance Thermometers ◽  
Resistance Thermometers
Sign in / Sign up

Export Citation Format

Share Document