DKD-R 5-4_Eng

DKD-R 5-4 ♦ Calibration of Temperature Block Calibrators

GERMAN CALIBRATION SERVICE

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Guideline Calibration of DKD-R 5-4 Temperature Block Calibrators

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Published by the Accreditation Body of the Deutscher Kalibrierdienst (DKD) at the PhysikalischTechnische Bundesanstalt (PTB) in co-operation with its specialized committee ”Temperatur and Humidity". Copyright © 2001 by DKD The document and all its parts are protected by copyright. Any unauthorized use outside the narrow limits set by the Copyright Act is inadmissible and liable to prosecution. This applies in particular to copies, translations, microfilming and storage and processing in electronic systems. Deutscher Kalibrierdienst (DKD)

The DKD comprises calibration laboratories in industrial enterprises, research institutes, technical authorities, inspection and testing institutes. They are accredited and supervised by DKD. They calibrate measuring instruments and material measures for measurands and measurement ranges specified within the scope of accreditation. The DKD calibration certificates issued by these laboratories prove traceability to national standards as required in the ISO 9000 family and ISO/IEC 17025. Calibrations carried out by DKD laboratories ensure that the user may rely on measurement results. They increase the customer confidence and competitiveness on the national and in ternational markets and serve as a metrological basis for the inspection of measuring and test equipment within the framework framework of quality assurance measures. Calibrations offered by DKD cover electric measurands, length, angles and other geometric quantities, roughness, coordinate and form measuring techniques, time and frequency, force, torque, acceleration, pressure, flow rate, temperature, humidity, medical measurands, acoustic measurands, optical measurands, ionizing radiation and other measurands. Publications: see Internet Address:

Deutscher Kalibrierdienst bei der Physikalisch-Technischen Physikalisch-Technischen Bundesanstalt Bundesallee 100, D-38116 Braunschweig POB 33 45, D-38023 Braunschweig Telephone secretariat:(0 5 31) 5 92-19 01 Fax: (0 5 31) 5 92-19 05 E-Mail: [email protected] Internet: www.dkd.info

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Table of contents Preface 1 Area of application 2 Calibration capability 3 Calibration 3,1 Axial temperature homogeneity along the boring in the measuring zone 3,2 Temperature differences between the borings 3,3 Influence of the temperature in the measuring zone by different loading 3,4 Temperature stability 3,5 Temperature derivations by heat conduction 3,6 Determination of the deviation between indication of the calibrator’s thermometer and the temperature in the measuring zone 4 Measurement uncertainty 4,1 Deviation between the indication of the standard thermometer and the temperature in the measuring zone 4,2 Temperature distribution in the block 4,3 Temperature derivations by heat conduction 5 Calibration certificate 6 Example of a measurment uncertainty analysis 7 Quoted standards and further documents Appendix A Procedure for the determination of the influence of the axial temperature distribution Appendix B Recommendations of the DKD specialized committee “Temperatur and Humidity” for the use of temperature block calibrators

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Preface DKD guidelines are application documents to the requirements of the DIN EN ISO/IEC 17025. In DKD guidelines technical and organizational operational sequence are described, which serve the calibration laboratories as model for the definition of internal procedures and regulations. DKD guidelines can become components of the quality management documentation of the calibration laboratories. The equal treatment of the devices which can be calibrated is promoted by the conversion of the guidelines in the different calibration laboratories and the continuity and examinableness of the work of the calibration laboratories are improved. The DKD guidelines are not the advancement of calibration procedures and -expirations to obstruct. Deviations from guidelines and new procedures are permissible in agreement with the accreditation body, if technical reasons speak for it. The guideline became of the specialized committee “Temperature and Humidity” in co-operation with the PTB provided and of the adviser of the DKD discharges. With the publication it becomes obligatory on all DKD calibration laboratories, if no own instruction for procedure approved by the accreditation body is present.

1. Area of application This guideline applies to temperature block calibrators, with those in a solid block an adjustable temperature is represented with the goal of calibrating in borings of this block thermometer. A temperature block calibrator consists at least of the solid block, a tempering equipment for the block and a block’s thermometer with indication for the determination of the block temperature. The components mentioned are summarized summarized either as compact device or must be each other clear to assign. The guideline applies in the temperature range of -80 °C to +1300 °C, whereby the temperature ranges indicated by the manufacturer may not be exceeded. Supplementary rules: Legal thermometric thermometric scale in the valid in each case version guidelines DKD-R 5-1, DKD-R 5-2, DKD-R 5-3 and future DKD guidelines within the range temperature.

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2. Calibration capability Calibration in the sense of this guideline are only such temperature block calibrators, which fulfill the following conditions: 2.1 For the measurement of the block temperature temperature a calibratable block’s thermometer thermometer must be used. A separate calibration of this thermometer is not a component of the calibration of the temperature block calibrators. 2.2 The borings used for calibrations calibrations must possess possess an exactly zone of sufficient sufficient temperature homogeneity of at least 40 mm of length, specified concerning their situation, (in the following as measuring zone designates). Usually the homogeneous zone will be at the lower end of the boring. If the homogeneous zone in another place should be, then is to be referred clearly to it. 2.3 It must be ensured that a calibration calibration under the following following conditions is possible: 2.3.1 The inside diameter of the used drilling or the used case may in the temperature range -80 °C until +660 °C maximum 0.5 mm and the temperature range +660 °C until +1300 °C maximum 1.0 mm more largely than the outside diameter of the assigned thermometer. Alternatively Alternatively a equivalent good or better heat contact can be manufactured by suitable heat distribution medium means. 2.3.2 The immersion depth of the thermometer must amount to at least the fifteenfold (15x) of the thermometer diameter.

3. Calibration In case of an adjustment of the calibrators is necessary, then this is to be accomplished before beginning of the calibration. During the calibration of a temperature block calibrators the special characteristics of the temperature distribution in the block of the calibrators are to be examined and documented except the deviation between the temperature in the homogeneous zone and the indication of the block’s thermometer, which is specified under section 3,1 to 3,5. If earlier investigations with calibrators of the same type for the determination of the characteristics or measuring uncertainties with to be consulted, then is in the calibration certificate to the available investigation reports to refer. All investigations must take place under the measurement measurement condition specified in section 2,3. If transition cases are necessary for the fulfilment of the demand in section 2.3.1, then must be manufactured this from the material suggested by the manufacturer. If the temperature block calibrator has one or more borings to co-ordinate in which an bushing is used, then is with the client which bushing (or bushings) is (are) to be used. If the bushing has several borings, then the borings in use are to be examined in such a way like several borings in the temperature block calibrator. The bushings are to be marked clearly. The thermometer (test thermometer), thermometer), used with the investigations to section 3,1 to 3,4, does not need to be calibrated, since it acts with th ese examinations around the measurements of temperature differences differences (exception: measurements measurements method 4. in the appendix A). However sensitivity must at the measuring temperature with sufficiently small small measuring uncertainty admits to be. As a rule sensitivity can be inferred from the applicable in each case standard, what is to be examined by a check measurement (possibly at another temperature). The used thermometers thermometers are to be examined for their stability. If with the client differently does not agree, the following measurement measurement conditions are to be kept: · All measurements measurements are with thermometers thermometers with outside diameter diameter D < 6 mm to accomplish accomplish · All measurements measurements with exception in section 3,1 of the specified are in such a way accomplished that the thermometer up-pushes at the lower end of the boring. In detail the following investigations are to be accomplished:

3.1 Axial temperature homogeneity along the boring in the measuring zone The influence of the temperature distribution in the measuring zone along the boring (axial temperature distribution) on the calibration of the thermometers it is to be determined in such a way that it can be considered in the measurement uncertainty of the calibration of the temperature block calibrators. Possible methods for this are represented in the appendix A.

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Earlier investigations with calibrators of the same type can be consulted for the determination of the contribution for the measurement uncertainty with. In arrangement with the client a restriction is possible on the investigation of the influence of the axial temperature distribution on certain types of thermometers. The measurement is to be accomplished in the central or a particularly marked boring. The necessary investigations are to be accomplished with the operating temperature, which exhibits the largest temperature difference to the ambient temperature. With temperature block calibrators, whose measuring zone can be heated and cooled both, the investigations are to be accomplished with the highest and the lowest operating temperature. The influence of the temperature distribution with other operatings temperature can be measured by linear interpolation (see for this the example in section 4,2).

3,2 Temperature differences between the borings The largest arising temperature difference between between the borings is to be determined. For the elimination of the influence of Temperature variations in temperature thereby the temperature differences are intended to an additional reference thermometer thermometer in the temperature block calibrator. Particularly importantly is the measurement of the temperature difference between between as far as possible apart lying (opposite) borings.

3,3 Influence of the temperature in the measuring zone by different loading With particularly small measurement uncertainty is necessary resuming investigations for the influence of the temperature in the measuring zone by different loading. For th is loadings with thermometers can be simulated by loadings with metal or ceramic(s) staffs. staffs.

3.4 Temperature stability The largest temperature difference is to be determined, which results in the case of firm attitude of the inspection temperature on the temperature block calibrator during an actual working time of 30 minutes in the measuring zone. Calibrations are to be accomplished at three different temperatures, with the highest and lowest desired application temperature and at ambient temperature. If the highest or deepest application temperature is at ambient temperature, then the third temperature for the calibration in the center of the temperature area of application is to be selected.

3,5 Temperature derivations by heat conduction In arrangement with the client the temperature derivation is to b e determined by heat conduction for such thermometers, which are to be calibrated with the client. This deviation is not regarded with the measurement measurement uncertainty indicated in the calibration certificate of the temperature block calibrator, but is with the bushing of the temperature block calibrator separately to be considered in each case. Temperature derivations by heat conduction for thermometers with outside diameter D < 6 mm can be neglected.

3,6 Determination of the deviation between indication of the block’s thermometer and the temperature in the measuring zone The determination of the temperature in the measuring zone of th e temperature block calibrator takes place with a standard thermometer, whose connection is to be traceable to the national standard laboratory. 3.6.1 Measurements the determination of the deviation between the indication of the block’s thermometer and the temperature, which can be accomplished, in the measuring zone takes place in the central or a particularly marked boring. In addition measurements are to be accomplished at at least three different temperatures (calibration points), which are as evenly as possible distributed over the desired area of application. At each calibration point two series of measurements are accomplished, in which over one period by at l east 10 minutes the temperature average value of the deviation between the indication of the block’s thermometer and the temperature in the measuring zone is determined in each case. The attitude of the temperature on the calibration points takes place for a series of measurements measurements with more rising, for the other one at falling temperature. Results, which were obtained during the measurement of temperature stability, may be used without repeat measurement, if a calibrated thermometer were used. With calibrations at the highest and/or the lowest temperature the demand is void according to attitude of the

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temperature at rising and falling temperature, if the temperature coincides with the highest or lowest operating temperature indicated by the manufacturer. However at least two series of measurements are to be taken up, between which the operating temperature of the calibrator was changed. 3.6.2 Evaluation for each calibration point is averaged the measured values from upward and downward measurement. measurement. The calibration result (deviation between the temperature measured with the standard thermometer and the indication of the block calibrators) is documented in mathematical, graphic or tabular form.

4. Measurement uncertainty As measuring uncertainty of the calibration of the temperature block calibrators is to be indicated that measurement uncertainty, uncertainty, which is to be assigned to the temperature in a boring of the calibrators. If the temperature derivation can be neglected by heat conduction, the measuring uncertainty is equal to the measurement uncertainty, which a user can expect during the calibration of a thermometer with the temperature block calibrator when careful adherence to of the operating instructions and this calibration guideline. An example of the computation of the measurement measurement uncertainty is to be found in section 6. As contributions to the measurement uncertainty are to be considered:

4,1 Deviation between the indication of the standard thermometer and the temperature in the measuring zone The contributions are essentially caused by the calibration of the standard thermometer, thermometer, the measurement measurement with the standard thermometer, thermometer, the drift of the standard thermometer, the dissolution of the announcement and differences of the measurements during upward and downward measurement (hysteresis). (hysteresis). The determination of the measuring uncertainties takes place in analogy to the procedure during the calibration of a thermometer. thermometer.

4,2 Temperature distribution in the block To step by those temperature distribution in the solid block, the loading of the th e block as well as temperature stability exactly did not admit additional deviations between the in dication of the block’s thermometer and the temperature of the measuring zone actually used by the user (those to be identical does not have with the zone, which was used for the measurements described in 3.6) up. These additional deviations can be regarded as from each other i ndependent. The thereby caused contributions to the measurement uncertainty can be measured from the measurements according to 3,1 to 3,4. The contribution ui to the measurement uncertainty becomes from the largest measured temperature 2 2 difference (t (t max – t min (t max – t min max – t min) derived: ui (t ) = (t max – t min) / 12, if at least three individual measurings were accomplished. If the contribution is intended ui for the measurement uncertainty from only two individual measurings 2 2 to select then is the following beginning: ui (t ) = (t (t 1 – t – t 2) / 3. The uncertainty contributions determined according to the sections 3,1 to 3,4 are to be linear interpolated between the calibration points. Deviating of it close of the ambient temperature in a temperature range, which extends symmetrically around the ambient temperature, can be set the contribution to the measurement uncertainty as constant. Example: With a calibration for a temperature block calibrator in the temperature range of -30 °C < t < +200 °C, which are accomplished with an ambient temperature of 20 °C, are found as largest temperature differences in the homogeneous zone: 0.3 K with t = -30 °C and 0.6 K with t = 200 °C. In the temperature range 20 °C + 50 K, thus of -30 °C to 70 °C, the largest arising temperature difference can be set to 0.3 K, in the temperature range 70 °C to 200 °C is between 0,3 K and 0.6 K linear to be interpolated.

4,3 Temperature derivations by heat conduction Of uncertainty contributions due to of temperature derivations by heat conduction of the thermometers with outside diameter D < 6 mm can be neglected. For thermometers with D > 6 mm is a separate view of this contribution to the uncertainty to be accomplished

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5. Calibration certificate The calibration certificate is in accordance with DKD-5 “Guidance for providing a DKD calibration certificate” to provide. It is recommended, each calibration certificate those ”Recommendations of the DKD specialized committee ‘Temperatur and Humidity’ for the application of temperature block calibrators” in the valid in each case version to attach (see appendix B). In the calibration certificate or as attachments to the calibration certificate also the results of the investigations are to be documented to 3,1 to 3,5.

6. Example of a measuring uncertainty analysis Calibration of a temperature block calibrators at the temperature 180 °C it is determined the temperature, which is to be attributed to the temperature feeling range of a thermometer during its calibration in a calibration boring of a temperature block calibrators also firmly inserted block’s thermometer, by comparison with a calibrated resistance thermometer (standard thermometer) at the calibration point 180 °C. The temperature of the resistance thermometer is determined by measurement of its electrical resistance with a circuit analyzer. The temperature, which is to be assigned to the value indicated by the block’s thermometer as temperature of the boring, results out t X = t S + δt S + δt D − δt δt iX δt H + δt Ax iX + δt Ax + δt Rad Rad + δt L + δt V With t S δt S δt D δt iX iX δt H δt Ax Ax δt Rad Rad δt L δt V

- Temperature of the resistance thermometer - Temperature correction due to the resistance measurement - Temperature correction correction due to drift by aging of the resistance thermometer since the last calibration - Temperature correction correction due to th e resolution of the indication of the block’s thermometer - Temperature correction due to hysteresis - Temperature correction due to insufficient axial homogeneity of the temperature distribution along the boring in the measuring zone (DKD-R 5-4: 3.1) - Temperature correction due to the temperature differences between the individual measuring borings (DKD-R 5-4: 3.2) - Temperature correction correction due to the loading of the calibration block with several thermometers (DKD-R 5-4: 3.3) - Temperature correction correction due to of variations of the temperature within the gate time (DKD-R 5-4: 3.4)

A temperature derivation by thermal conduction is not considered, since the resistance thermometer possesses an outside diameter d diameter d < < 6 mm (DKD-R 5-4: 3.5). Resistance thermometer (standard thermometer) (t S): The calibration certificate for the resistance thermometer used as standard thermometers indicates the relationship between resistance and temperature. The measured resistance resistance value corresponds to a temperature of 180,10 °C with an assigned to extended measurement uncertainty of 30 mK (coverage factor k = 2). Determination of the temperature by resistance measurement (δt S): The temperature as use standard of used resistance thermometer is determined with 180,10 °C. The standard measuring uncertainty of the resistance measurement converted to temperature corresponds u(δt N) = 10 mK. Drift of the resistance value of the resistance thermometer (δt D): From the general behavior of the kind used by resistance thermometers the deviation of the resistance value of the assigned resistance thermometer due to its aging since the last calibration measured with the borders ±40 mK. Resolution of the indication of the block’s thermometer (δt iX iX): The indication of the block’s thermometer is able to indicate temperature levels in steps of 0,1 K. The temperature derivation due to the finite resolution of the indication lies therefore in the borders ±50 mK. Hysteresis with ascend and descending measuring cycle (δt H): The measured values show, that the temperature derivation due to hysteresis within the range, arising with ascend and descending measuring cycle ±50 mK. Axial homogeneity (δt Ax Ax): From the measured maximum and minimum temperature levels in the measuring zone of the boring the temperature derivation is measured due to the axial inhomogeneity by the borders ±250 mK.

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Temperature differences between the borings (δt Rad Rad): The calibrator which can be calibrated possesses 6 borings. The l argest measured temperature difference amounted to 140 mK, from which for the temperature distribution between the borings borders are measured by ±70 mK. Temperature derivation due to the loading (δt L): From the measured temperature differences a possible deviation due to the loading of the individual borings measured to ±50 mK. Temperature stability (δt V): Temperature derivations due to temperature variations during the gate time of 30 min are measured by the borders ±30 mK. Correlations: Correlations between between the values of the inputs are regarded as insignificant.

Measuring uncertainty budget: Factor

Estimated value

X i t S δt S δt D δt iX iX δt H δt Ax Ax δt Rad Rad δt L δt V t x

xi O 180,10 C 0,00 K 0,00 K 0,00 K 0,00 K 0,00 K 0,00 K 0,00 K 0,00 K O 180,10 C

Standard measurement uncertainty u( xi) 15 mK 10 mK 23 mK 29 mK 29 mK 144 mK 40 mK 29 mK 17 mK

Distribution

Sensitivity Coefficient

Normal Normal Rectangular Rectangular Rectangular Rectangular Rectangular Rectangular Rectangular

ci 1,0 1,0 1,0 -1,0 1,0 1,0 1,0 1,0 1,0

Uncertainty contribution ui( y) y) 15 mK 10 mK 23 mK -29 mK 29 mK 144 mK 40 mK 29 mK 17 mK 161 mK

Extended measurement uncertainty: Those the result assigned to standard measuring uncertainty is dominated by the effect of the unknown temperature correction regarding the axial temperature inhomogeneity in the measuring boring and the radial temperature difference between the measuring borings. The resulting distribution is not essentially trapezoidal a standard distribution, b ut. Details for  = this are described in DKD-3-E2, section S10.13. For the above example an edge parameter resultsβ resultsβ 0,563, which leads for a probability of cover from 95 % to an coverage factor k = 1.74.

U = U = ku (t x) = 1,74 · 0,161 K ≅ K ≅ 0,3 K Complete result of measurement: The temperature, those the indication of 180,0 °C, the indicated of inserted calibrator’s thermometer is assigned, amounts to

180,1 °C ± 0,3 K The indicated extended measurement uncertainty is the product of the standard measuring uncertainty and the coverage coverage factor k = 1,74. It corresponds corresponds to a probability of cover of 95 % during during the accepted accepted trapezoidal probability distribution. the standard measuring uncertainty in accordance with DKD-3 (authorized translation of EA-4/02) was determined.

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7. Quoted standards and further documents DIN EN ISO/IEC 17 025 General requirements requirements for the competence competence of testing and calibration laboratories DIN 43 762

Measurement and control; electrical temperature sensors; sensor units for resistance thermometers

DIN 43 735

Measurement and control; electrical temperature sensors; sensor units for thermocouple thermometers thermometers

DKD-R 5-1

Guideline of the German calibration service (DKD) for the calibration of precision resistance thermometers according to the comparison method

DKD-R 5-2

Guideline of the German calibration service (DKD) for the calibration of technical resistance thermometers according to the comparison method

DKD-R 5-3

Calibration of thermocouples

DKD-5

Guidance for providing a DKD calibration certificate

DKD-3

Statement of the measurment uncertainty with calibrations (German translation of EA-4/02 “Expression of the Uncertainty of Measurement in Calibration”)

DKD-3-E2 DKD-3-E2

Statement of the measurement measurement uncertainty with calibrations: Additional examples (German translation of EA-4/02 “Expression of the Uncertainty of Measurement in Calibration”, Supplement 2)

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Appendix A: Method for the determination of the influence of the axial temperature distribution Temperature block calibrators are usually inserted for the calibration by thermometers with different structure. Sensors of different length are thereby in different ranges of the measuring zone. Therefore the axial temperature distribution supplies with along the boring in the measuring zone (frequently all other contributions dominating) a contribution for the uncertainty of the calibration. The determination of the axial temperature distribution is difficult, since a test thermometer affects this temperature distribution. This influence can be complex, since e.g. a thermometer with differently immersion immersion depth causes in each case different heat conduction, what then however reactions to the automatic controller action of the block calibrators have can. Therefore a method for the determination of the influence of the axial temperature distribution is to be selected, which corresponds to the customer requirements if possible. Such procedures can be e.g.:

1. Determination of the temperature at 3 points with a sensor of short overall length In addition becomes with a thermometer with a sensor length of maximally 5 mm the temperature at the lower end, in which center determines and at the upper end of the measuring zone. The thermometer may be provided with a protective pipe with outside diameter D < 6 mm. In the temperature range -80 °C to 250 °C are preferably Pt-Resistance Pt-Resistance thermometers and Thermocouples to use in the range 250 °C until 1300 °C (also Pt-Pd Thermocouples). Example: With a temperature block calibrator with a measuring zone of 40 mm o f length at the lowest end of the boring measurements under the following conditions are necessary: 1) thermometer touching the ground, 2) 20 mm pulled out, 3) 40 mm pulled out, 4) thermometer touching the ground.

2. Direct regulation of temperature differences by means of difference thermocouple Here the temperature difference at one or more points in the boring, the deepest point of the boring becomes (touching the ground) directly measured with a difference thermocouple. For this e.g. a finished manufactured thermocouple can be used, with that the two measuring points a distance from possess approximately 25 mm. It should be tested for example in a bath or a heat pipe regularly, whether the temperature difference is correctly one measure by 0 K. Another possibility is it, to introduce two coat thermocouples together with small outside diameter to the drilling. While the first thermocouple remains at the g round, the temperature differences are intended for the second thermocouple, in well-known distance to the first thermocouple is (e.g. 20 mm and 40 mm). Both thermocouples dived in directly deeply, is an alignment for the temperature difference 0 K possible.

3. Determination of the temperature at two points The temperature distribution is determined with the help of a thermometer with relatively long sensor, So a shift of the thermometer over 40 mm (the usual length of the homogeneous zone of the block calibrators) is not meaningfully. With some calibrators turned out, that a measurement with two different immersions (e.g. touching the ground and 20 mm pulled out) sufficient information for the influence of the temperature distribution on the contribution to the measuring uncertainty to supply can. One considers, that according to section 4.2 in this case the contribution to the measuring uncertainty in accordance with ui2(t ) = (t (t 1 - t 2)2 / 3 is determined.

4. Determination of the temperature with calibrated thermometers with different sensor length Couches information about it forwards, which thermometers in the block calibrator are calibrated, so the influences of the axial temperature distribution on the type of thermometer can be determined directly. For this measurements with the respective thermometer types are necessary. If no information about those is present thermometers which can be calibrated, so the measurement with two thermometers of different a design as possible should be accomplished. It is to be considered, that for these under this method specified measurements all used thermometers must to be calibrated.

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Appendix B: Recommendations of the DKD specialized committee ‘Temperatur and Humidity’ for the application of temperature block calibrators By the calibration certificate of a DKD calibration laboratoris it is confirmed that the temperature block calibrator fulfills the high requirements to the calibration capability of such an equipment, as they are fixed in the guideline DKD-R 5-4. Nevertheless Nevertheless the following points are to be considered with the bushing of the calibrators: The calibration of temperature block calibrators predominantly refers to the temperature of the solid block. The temperature of the thermometer which can be calibrated in the block can deviate from this temperature. If a thermometer of the same type is used under same measurement condition as during the calibration, can be assumed the measuring deviations are not larger during the calibration of ideal thermometers thermometers than the measurement measurement uncertaintyen indicated in the calibration certificate. If in the calibration certificate nothing different one is indicated, it must be guaranteed that · the measuring element element is in the homogeneous homogeneous temperature temperature zone. · the inside diameter of the used boring boring in the calibrator (possibly (possibly the case) in the temperature temperature range -80 °C up to 660 °C maximum 0.5 mm and the temperature range 660 °C until 1300 °C maximum 1.0 mm is larger than the outside diameter of the thermometer which can be calibrated. · the submergence of the thermometer thermometer which can be calibrated at least the fifteenfold fifteenfold (15x) of the outside diameter of the thermometer which can be calibrated. · the thermometer thermometer an outside diameter diameter which can can be calibrated hasd hasd < < 6 mm. Please you pay attention particularly whether during the calibration of your temperature block calibrators a heat distribution medium means was used. If this is th e case, then the calibration applies only with bushing of the calibrators with an appropriate heat distribution medium means. During the calibration of thermometers with outside diameter d > d > 6 mm is an additional measuring deviation by heat conduction to be considered. If such measurements are to be accomplished, then the additional heat conduction can be intended for the type of thermometer thermometer examined with you by your DKD calibration laboratory. A good test on possible temperature derivations by heat conduction consists of checking whether the indication changes of the thermometer which can be calibrated, if it is raised by 20 mm. Contributions to the measurement uncertainty, which are due to the thermometer (e.g. inhomogeneities of thermocouples), which can be calibrated from you to, are not likewise not in the measurement measurement uncertainty of the Calibrators contained. If the calibrator is used in loading conditions, which do not correspond to the loading condition during the calibration, then the influence of the loading can be determined by removal or adding thermometers locally. For the calibration the data are relevant in the calibration certificate, not the manufacturer data. Please absolutely agree upon before the calibration the bushing and calibration conditions with your DKD calibration laboratory. If in the calibration certificate nothing different one is indicated, it must be guaranteed (independently of manufacturer data) that · the calibrator is operated in vertical position · additional thermal thermal isolations isolations to be used · the ambient temperature (23 + 5) °C amounts to. As a check of the calibration of temperature block calibrators one recommends to make regular measurements with a calibrated thermometer. Without check measurements with a calibrated thermometer an annual recalibration of the temperature block calibrators is urgently recommended.

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DKD-R 5-4_Eng

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