Methods of reducing the uncertainty of the self-heating correction of a standard platinum resistance thermometer in temperature measurements of the highest accuracy

Batagelj, V.; Bojkovski, Jovan; Drnovšek, J.

doi:10.1088/0957-0233/14/12/016

Cited by 31 publications

(21 citation statements)

References 4 publications

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“…In this case, the reference temperature is t 0 , which is the measured temperature without electrical current passing through the platinum element, and t is the measured temperature when a current I passes through the platinum element. The thermal resistance r t can be divided into internal thermal resistance r t i , due mainly to the design of the thermometer, and the external thermal resistance r t e due mainly to the environment surrounding the thermometer (Batagelj et al, ; ).

r_{t} = r_{t normali} + r_{t normale}

…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Evaluation of the self‐heating effect in a group of thermometers used in meteorological and climate applications

Izquierdo

Hernández

González

et al. 2019

Meteorological Applications

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A procedure for the metrological evaluation of the self‐heating effect in resistance thermometers is reported. This procedure is applied to different designs of resistance thermometers, used for meteorological and climate applications. The study of the self‐heating effect variation with the applied electrical current, temperature and different surrounding environments is described, as well as the influence of wind speed on the self‐heating effect.

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r_{t} = r_{t normali} + r_{t normale}

…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Evaluation of the self‐heating effect in a group of thermometers used in meteorological and climate applications

Izquierdo

Hernández

González

et al. 2019

Meteorological Applications

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“…The Cernox sensor therefore measures a higher temperature T instead of the actual temperature T 0 , which would be measured without the self-heating effect [6]. The temperature difference T  can therefore be calculated as:…”

Section: Theoretical Backgroundmentioning

confidence: 99%

The Measurement and Uncertainty Analysis of Thermal Resistance in Cryogenic Temperature Sensor Installation

Zhang

Dong

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. The choice of the appropriate installation method plays an important role for accurate temperature measurement. In the cryogenic and high vacuum environment, due to poor contact between the cryogenic temperature sensor and the surroundings that the sensor is installed and intended to measure, the self-heating from sensor measuring current brings about temperature difference and creates a potential temperature measurement error. The self-heating temperature difference is directly proportional to the thermal resistance for a mounted sensor, which means that lower installation thermal resistance of sensors is advantageous to obtain better measurement results. In this paper, a measurement model for the installation thermal resistance of sensor is built in terms of two currents method which is always used to measure self-heating effect. A cryostat that can provide variable temperature in the accurate temperature measurement and control experiments is designed and manufactured. This cryostat can reach 3K in a few hours and the sample temperature can reach as high as 20 K. Based on the experimental results, the measurement uncertainty of the thermal resistance are also analyzed and calculated. To obtain the best measurement results in our cryostat, the thermal resistances of sensors with two installation methods are measured and compared. IntroductionOperation of resistance thermometer requires dissipation of power in the sensor. The heat flux generated by the measurement current creates the temperature difference between the sensor and the environment is intended to measure, which is no doubt to produce temperature measurement error or uncertainty. The self-heating temperature difference relates to the thermal resistance between the sensor and its surroundings. Thermal resistance is a significant factor in temperature measurement uncertainty. How to accurately measure the thermal resistance between the sensor and the environment is an important problem in high precise temperature measurement. Thermal resistance is found to depend on temperature and details of sensor mounting. Apiezon grease and Varnish are always used to mount thermometer sensors in low temperature, because they have high thermal conductivity in low temperature. Details of construction unknown to a user can strongly affect the thermal resistance. It is difficult to calculate an effective thermal resistance for a mounted temperature sensor. Many scholars have done research on the thermal resistances of the cryogenic temperature sensors. Rusby [1] studied the thermal resistances of a standards grade rhodium-iron sensor from 0.4 to 280K; Schoepe [2] calculated the thermal resistances of a thick film resistor from 0.4 to 280K. Thermal resistances were measured at cryogenic temperatures from 1 to 300K on several commercially available temperature sensors by Holmes and Courts [3]. In this paper, the thermal resistances of the Cernox temperature sensor that mounted by two different methods (Apiezon N Grease, VGE-7031 varnish) from 4.2 to 14K are c...

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“…Self heating is the phenomenon that occurs when the measurement current additionally heats the PRT sensor, [7]. In a fixed-point calibration, this effect is usually corrected by measuring with two different currents.…”

Section: Influence Of Self Heatingmentioning

confidence: 99%

Calibration by Comparison of Platinum Resistance Thermometers Using Slow Resistance Bridges

Batagelj

Bojkovski

2011

Int J Thermophys

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Platinum resistance thermometers (PRTs) are calibrated at the highest level in fixed points, as specified in the International Temperature Scale of 1990 (ITS-90). However, in order to reduce cost and time, platinum resistance thermometers can also be calibrated by comparison. In the temperature range from −100 • C to 300 • C, it is possible to achieve uncertainties as small as 5 mK. A PRT is calibrated by comparison by comparing its resistance reading with the temperature reading of a reference thermometer, placed at the same temperature inside the temperature-controlled calibration medium. The reference thermometer is commonly also a resistance thermometer, so the intrinsic measurement problem is the simultaneous measurement of two resistances. Four methods that perform this measurement are presented in this article. A special emphasis is given to the measurement with slow bridges. Slow bridges are not able to produce a stable resistance reading within 20 s after the connection of the PRT, so they are often considered to be unsuitable for calibration by comparison of PRTs. To overcome this problem, a special method that directly measures the ratio between the reference PRT and PRT under calibration is presented and analyzed. The analysis and measurement results proved that this method and consequently the slow resistance bridges are capable of performing calibration by comparison of PRTs at least at the same level as the conventional methods.

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Methods of reducing the uncertainty of the self-heating correction of a standard platinum resistance thermometer in temperature measurements of the highest accuracy

Cited by 31 publications

References 4 publications

Evaluation of the self‐heating effect in a group of thermometers used in meteorological and climate applications

Evaluation of the self‐heating effect in a group of thermometers used in meteorological and climate applications

The Measurement and Uncertainty Analysis of Thermal Resistance in Cryogenic Temperature Sensor Installation

Calibration by Comparison of Platinum Resistance Thermometers Using Slow Resistance Bridges

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