A Slimline Integrated Self-Validating Thermocouple: Initial Results

Elliott, C. J.; Greenen, A.; Tucker, Declan; Ford, T.; Pearce, J. V.

doi:10.1007/s10765-017-2274-y

Cited by 7 publications

(5 citation statements)

References 3 publications

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“…Commonly available PCMs are available with a wide range of phase change temperatures and can therefore be used for many calibration applications. For example, metal-carbon eutectics (MCE) have been being used for high-accuracy, high-temperature industrial applications [1,2] up to 2474 °C (Re-C). Over the past decade moreaccurate versions of these same MCEs are routinely used in metrology laboratories for thermodynamic temperature dissemination, extending fixed-point temperatures beyond the copper point (1084 °C) [3,4].…”

Section: In Situ Temperature Calibration For Critical Applications Ne...mentioning

confidence: 99%

In situ temperature calibration for critical applications near ambient

Webster

Clarke

Mason

et al. 2020

Meas. Sci. Technol.

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Many agricultural, medical and food storage applications require both accurate and reliable knowledge of the temperature to guarantee quality and enable sound decision making. For example, grape growers incur large costs when they are not able to accurately predict frosts; vaccine and blood products need to be stored within a known temperature range, and the longevity of many food goods depends on stable storage temperatures. Although many systems offer accurate temperature measurements for these applications, these systems are often exposed to conditions that may compromise either the sensor or the measurement equipment, often without the knowledge of the user. To provide on-going confidence in automated temperature logging systems, a low-cost, robust and easy-to-use after-market solution is needed. One such solution is based on organic phase-change materials, which are inexpensive, have low toxicity and are demonstrated to provide highly repeatable transition temperatures. By attaching a small vial of the chosen material to an existing temperature sensor, a brief plateau can be induced as the temperature changes, signalling a known temperature to the control system or user. This repeatable temperature 'marker' provides ongoing assurance that the temperature monitoring system is operating correctly. In this study, several promising materials are trialled in the range of 1 °C to 7 °C. Initial results show the method to be a practicable and affordable addition to critical monitoring and control systems.

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Section: In Situ Temperature Calibration For Critical Applications Ne...mentioning

confidence: 99%

In situ temperature calibration for critical applications near ambient

Webster

Clarke

Mason

et al. 2020

Meas. Sci. Technol.

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“…The thermocouples (Cu B and Cu C) had already undergone several hours of use as part of the initial test plan (described elsewhere [1]) before being used for this test. In figure 3, it can be seen that three of the four Cu thermocouples tested at NPL had a stability of better than ±2.5 °C.…”

Section: Tests At Npl (Cu)mentioning

confidence: 99%

“…As part of the European Metrology Programme for Innovation and Research (EMPIR) project 'EMPRESS' (project label 14IND04), the design of the NPL slim-line inseva thermocouple has been developed and tested further than previously reported [1,2]. The temperature fixed-point cell (containing a Cu, Co-C or Ni-C ingot) is integrated inside a standard, 7 mm outer diameter, recrystallised alumina protective sheath.…”

Section: Introductionmentioning

confidence: 99%

“…In general, thermocouples used at high temperatures (typically over 1000 °C) will drift from their initial calibration state, resulting in an incorrect temperature reading which becomes worse with time [1]. In industrial applications, where the long term monitoring of high temperature processes or reliable repetition of thermal processes is vital, this can become a serious issue.…”

Section: Introductionmentioning

confidence: 99%

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Integrated self-validating thermocouples with a reference temperature up to 1329 °C

Tucker

Andreu²,

Elliott

et al. 2018

Meas. Sci. Technol.

Self Cite

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Thermoelectric instability, or calibration drift, is a major problem for users of thermocouples at high temperature. NPL, in collaboration with CCPI Europe, AFRC and ICPE-CA/BRML-INM has designed, made and industrially tested Type S thermocouples with integrated temperature fixed-point cells. These in situ, self-validating thermocouples (denoted 'inseva') have the same external dimensions as conventional industrial thermocouples (the recrystallised alumina sheath has an outer diameter 7 of mm). The device can be used to detect the melting and/or freezing temperature of the integrated temperature fixed-point ingot, which enables a self-validation to be performed whilst in situ. During the testing, three different reference ingots were used in the cells, namely: copper (1084 °C), cobalt-carbon (1324 °C) and nickel-carbon (1329 °C). The metrological performance for two iterations of the design are presented, with an emphasis on the ability of the inseva thermocouples to indicate their own thermoelectric stability. A measurement uncertainty budget is also given for the case of a Ni-C inseva thermocouple. This paper demonstrates that inseva thermocouples can be successfully validated during industrial processes through the observation of the melting plateau, as well as their robustness over time in industrial conditions. A key finding is that the Ni-C eutectic alloy is much more robust than the Co-C eutectic alloy for the used type of graphite crucible, making the Ni-C inseva thermocouple more suitable for industrial applications, and a good alternative.

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“…The articles describe issues related to the optimization of the furnace temperature curve [ 1 ], a thermal conductivity sensor for gas detection [ 2 ], or a prototype of a variable temperature insert intended for the calibration of cryogenic thermometers [ 3 ]. Various techniques for calibrating temperature sensors are also described [ 4 , 5 , 6 , 7 ]. The articles [ 8 , 9 , 10 ] present research showing the influence of fluid flow speed on the time constant and measurement errors of temperature sensors.…”

Section: Introductionmentioning

confidence: 99%

Time Constant as the Main Component to Optimize the Resistance Temperature Sensors’ Calibration Process

Klebba,

Frącz,

Brodzicki

et al. 2024

Sensors

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Temperature sensor calibration in the majority of measurement laboratories is performed on the ground of measurement procedures. The procedures specify the timespan for the temperature of the tested sensor to stabilize. In practice, the fact of time constant increase above expectations can be observed. This results from the method of operation, time of use, and level of contamination of individual sensors. The paper proposes a method to optimize the calibration process of resistance temperature sensors based on the measurement of the time constant and, on this basis, to determine the sensor stabilization time during calibration.

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A Slimline Integrated Self-Validating Thermocouple: Initial Results

Cited by 7 publications

References 3 publications

In situ temperature calibration for critical applications near ambient

In situ temperature calibration for critical applications near ambient

Integrated self-validating thermocouples with a reference temperature up to 1329 °C

Time Constant as the Main Component to Optimize the Resistance Temperature Sensors’ Calibration Process

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