The Constancy of Thermoelements

Measurement Science Review

Przystupa

et al. 2019

Error due to inhomogeneity is the main problem of thermocouples (TCs), e.g., during the operation of a type K TC, this error can reach 11-30 °C. Thus, metrological reliability of TCs is threatened by this error because there is a high risk of exceeding the permissible error when the temperature distribution along the TC legs changes. Such a large error, in turn, can threaten a proper operation or even safety of a measured object. A TC with controlled temperature field was proposed to cope with this error. An information-measuring system to perform proper measurements, measurement data acquisition and collection to construct mathematical models is proposed. Its property is high diurnal stability of ±(0.0025+0,002(X/XMAX–1) %. The requirements for the information-measuring system and its structure are considered in this paper. In particular, one of the key problems of such a sensor is how stable is its own temperature field under the influence of the temperature field of a measured object. The experimental studies were carried out using the developed system. They showed that the coefficient of penetration of the temperature field of the measured object is about 0.04. This allows decreasing error due to inhomogeneity by about 10-20 times.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Information-measuring System to Study the Thermocouple with Controlled Temperature Field

Wang

Measurement Science Review

Przystupa

et al. 2019

“…For the first time, the problem of thermoelectric inhomogeneity was considered in 1906 [43], but according to [29,30,32,44] it still remains one of the main sources of error in temperature measurements using TC. Despite the studies in this field [40,42,[44][45][46][47] the problem has still not been solved yet.…”

Section: E3s Web Of Conferencesmentioning

confidence: 99%

“…Despite the studies in this field [40,42,[44][45][46][47] the problem has still not been solved yet. Thermoelectric inhomogeneity is considered to be the main source of TC error [30,43] The ways to increase the accuracy of temperature measurements by TCs with significant acquired during long-term operation thermoelectric inhomogeneity of legs were proposed in the paper [48]. The method of correction of this error was considered and studied in the paper [49].…”

Section: E3s Web Of Conferencesmentioning

confidence: 99%

Designing an accurate system for temperature measurements

2017

E3S Web Conf.

Abstract. The method of compensation of changes in temperature field along the legs of inhomogeneous thermocouple, which measures a temperature of an object, is considered in this paper. This compensation is achieved by stabilization of the temperature field along the thermocouple. Such stabilization does not allow the error due to acquired thermoelectric inhomogeneity to manifest itself. There is also proposed the design of the furnace to stabilize temperature field along the legs of the thermocouple which measures the temperature of an object. This furnace is not integrated with the thermocouple mentioned above, therefore it is possible to replace this thermocouple with a new one when it get its legs considerably inhomogeneous.. There is designed the two loop measuring system with the ability of error correction which can use simultaneously a usual thermocouple as well as a thermocouple with controlled profile of temperature field. The latter can be used as a reference sensor for the former.

“…The first known paper devoted to problems of thermoelectric inhomogeneity was written in 1906 [23], and the first known review and generalization of the existing methods for investigating inhomogeneity was made in [24]. A lot of time passed since then, but the problem is still topical [7] despite quite a big number of investigations of inhomogeneity of TCs [11]- [17], [25]- [27].…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Research of Error of Method of Thermocouple with Controlled Profile of Temperature Field

Measurement Science Review

Wang

et al. 2015

The method of study and experimental researches of the error of method of the thermocouple with controlled profile of temperature field along the main thermocouple are considered in this paper. Experimentally determined values of error of method are compared to the theoretical estimations done using Newton's law of cooling. They converge well.Keywords: Thermocouple, inhomogeneity of thermocouple, controlled profile of temperature field, measurement error, error of method.