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Standard platinum resistance thermometer

The ITS-90 has its lowest point at 0.65 K and extends upward without specified limit. A number of values assigned to fixed points differ from those of the immediately previous scale, IPTS-68. In addition, the standard platinum resistance thermometer (SPRC) is specified as the interpolation standard from 13.8033 K to 961.78°C, and the interpolation standard above 961.78°C is a radiation thermometer based on Planck s radiation law. Between 0.65 and 13.8033 K interpolation of the scale rehes upon vapor pressure and constant-volume gas thermometry. The standard thermocouple, which in previous scales had a range between the upper end of the SPRT range and the lower end of the radiation thermometer range, has been deleted. [Pg.399]

Caprylic/capric triglyceride, cosmetically useful lipid, 7 833t Capsanthin, 24 560 Capsicum group, 23 164-165 Capsorubin, 24 560 Capsular polysaccharides, 20 455 Capsules. See also Microencapsulation extruding, 16 446 pharmaceutical, 18 708 produced by spray drying, 16 447-448 Capsule standard platinum resistance thermometers, 24 445 Captafol, 23 629, 647 Captan, 23 628 Captiva camera, 19 307 Captive hydrogen, 13 841 Captopril, 5 148... [Pg.138]

The International Practical Temperature Scale of 1968 (IPTS-68) is currently the internationally accepted method of measuring temperature reproducibly. A standard platinum resistance thermometer is the transfer medium that is used over most of the range of practical thermometry. [Pg.6]

In 1821, Sir Humphrey Davy discovered that as temperature changed, the resistance of metals changed as well. By 1887 H.L. Callendar completed studies showing that purified platinum wires exhibited sufficient stability and reproducibility for use as thermometer standards. Further studies brought the Comitd International des Poids et Measures in 1927 to accept the Standard Platinum Resistance Thermometer (SPRT) as a calibration tool for the newly adopted practical temperature scale. [Pg.167]

Iron-Constantan thermocouples, which had been calibrated against an N.B.S.-standardized platinum resistance thermometer, measured both the sample temperature and the difference in temperature between sample and reference tubes. The thermocouple wires were embedded in magnesia and electrically insulated from their Inconel sheaths. The signal of the thermocouple in the sample tube could be determined either by a recording potentiometer or by a manual potentiometer and null meter. [Pg.310]

Figure 5. Gallium melting curves of large cells obtained with standard platinum-resistance thermometers. Scale on left is for the top curve, resistance bridge values ranging from 28581000 to 28585000 are for the middle curve the remaining scale on the right is for the bottom curve. Figure 5. Gallium melting curves of large cells obtained with standard platinum-resistance thermometers. Scale on left is for the top curve, resistance bridge values ranging from 28581000 to 28585000 are for the middle curve the remaining scale on the right is for the bottom curve.
As mentioned above, a special PRT that satisfies the specifications of ITS-90 is the defining standard thermometer (called the standard platinum resistance thermometer, SPRT) for the range of temperatures from 13.80 to 1234.93 K (961.78°C). According to ITS-90 [2], an acceptable SPRT must be made from sufficiently pure and strain-free platinum wire, and it must satisfy at least one of the following two relations ... [Pg.1171]

Standard platinum resistance thermometers (SPRTs) are the most accurate and most delicate RTDs in existence. Their applications are largely limited to standard laboratories and other applications requiring temperature accuracies of 1 mK or better. SPRTs are the primary interpolation instrument in the very definition of temperature in the International Temperature Scale of 1990 (ITS-90) from 13.8033 K (the triple point of... [Pg.2935]

Calibration at fixed points is a complex process. Standard platinum resistance thermometers and standard platinum-rhodium-platinum thermocouples are calibrated at fixed points for use as primary standards. It is recommended that calibration be done by the NBS or other qualified laboratory. The narrow-band optical pyrometer is another primary standard its range over the fi%ezing point of gold is obtained through extrapolation. Ordinary calibration of temperaturemeasuring instruments is effected by comparison of their readings with those of primary or secondary standards at temperatures other than fixed points. Comparators are used to produce those temperatures. [Pg.463]

Secondary standards are liquid-in-glass thermometers and base-metal thermocouples. They are calibrated by comparing them with primary-standard platinum-resistance thermometers or standard platinum-rhodium versus platinum thermocouples at temperatures generated in comparators. These secondary standards are used in turn for the calibration of other devices, such as liquid-in-glass thermometers, bimetallic thermometers, filled-system thermometers, and base-metal thermocouples, in which the highest degree of accuracy is not required. Optical pyrometers as secondary standards are compared with primary-standard optical pyrometers, and they are then used for calibration of r ular test pyrometers. [Pg.463]


See other pages where Standard platinum resistance thermometer is mentioned: [Pg.925]    [Pg.20]    [Pg.397]    [Pg.406]    [Pg.438]    [Pg.533]    [Pg.397]    [Pg.406]    [Pg.925]    [Pg.290]    [Pg.1161]    [Pg.1162]    [Pg.1167]    [Pg.2935]    [Pg.1784]    [Pg.1784]   
See also in sourсe #XX -- [ Pg.290 ]




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