Effects of Quartz Glass Insulation on Platinum Gold Thermocouples

Abstract

Au/Pt thermocouples are considered as an alternative to High Temperature Platinum Resistance Thermometers and are one of the prime candidates to replace them as the interpolating instrument of the International Temperature Scale of 1990 (ITS-90) in the temperature range between about 660 °C and 962 °C. This work presents the results of investigation of two Au/Pt thermocouples that used exclusively quartz glass (SiO2) as insulation material. Measurements in fixed points of Zn, Al, and Ag were realized on these thermocouples as well with interchanged inner insulation made of high purity aluminium oxide (Al2O3). The conducted experiments tested the performance of Au/Pt thermocouples with the use of different insulation materials. The measured electromotive forces were found to be sensitive to the replacement of the quartz glass by aluminium oxide as an insulation material of the Au/Pt thermocouples. This change of insulation has resulted in a temperature increase up to about 0.5 K measured at the freezing point of silver. The decreasing insulation resistance of quartz glass at higher temperatures is believed to be the source of thermoelectric instability.

Development of a Temperature and Heat Flux Measurement System Based on Microcontroller and its Application in Ophthalmology

“…In spite of the large number of temperature sensors [12], [20]- [22] and noninvasive methods of measurements [23], the conventional thermocouple is a very important sensor and much attention is paid to its study. For example, EURAMET issued a roadmap for thermometry [16], which declares the need for further study of a thermocouple.…”

“…For example, EURAMET issued a roadmap for thermometry [16], which declares the need for further study of a thermocouple. The study is carried out in three directions: (i) study of the existing thermocouples [17]- [19]; (ii) study of new materials which can be used for thermocouples [20]- [22]; (iii) study of novel designs based on the conventional thermocouples [24], [25]. This paper considers the studies in the directions (i) and (iii).…”

InAsSb Photodiode Fibre Optic Thermometry for High-Speed, near-Ambient Temperature Measurements

“…The measurement of temperature is critical in many sectors of industry and science [1][2][3][4][5][6][7]. The ability to perform fast, accurate, and reliable temperature measurements is essential for understanding temperature-dependent phenomena and improving process efficiency and quality [5,8].…”

“…Contact-based thermocouples have been the standard thermometer used for many industrial and scientific measurements because of their low capital and installation costs and their capability of measuring a wide range of temperatures [9]. However, thermocouplebased techniques inherently have limitations, such as requiring precise and invasive contact; low responsiveness and sensitivity, making them ineffective and unreliable for high-speed measurements; low chemical resistance, which can deteriorate measurement accuracy and contaminate the measurand; high rates of calibration drift and hysteresis; and accuracy limitations [5][6][7][8][9][10].…”

Computer Modelling of Two-level Digital Frequency Synthesizer with Poisson Probability Distribution of Output Pulses

“…That is why the market of metrological service constitutes a considerable share of GDP in developed countries [7], [8]. The progress of instruments and instrumentation lies in standardization [9], error elimination techniques [10] and increasing metrological reliability of measurement results [11], developing new metrological techniques [12], [13], developing new verification and calibrating techniques, including calibration in-situ [14]- [16]. This progress is called for, because proper measurement instruments and sensors lead to considerable gain in ecology [17], [18], economy [18], science [19], medicine [20] and other areas, therefore studies in the field of metrological service are relevant and topical [11], [15].…”