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INM
Institutul National de Metrologie
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LENGTHS LABORATORY

INM LABORATORIES

General InformationThe Management Team
Organizational Chart

 

 

  • TEMPERATURE AND OPTICAL QUANTITIES LABORATORY   


OPTICAL QUANTITIES GROUP


Mission:

  • Development and operation of the national and reference standards for the photometric, radiometric and spectrophotometric units;
  • Units dissemination at national level according to the Mutual Recognition Arrangement for national measurement standards and calibration certificates issued by the NMIs (CIPM-MRA) requirements.

To achieve these objectives, 5 national standards are continuously maintained, operated and improved, ensuring their permanent connection to the International System of Units or other internationally recognized references through CIPM-MRA mechanisms.


National measurement standards

Quantity National standard Value(s) Associated standard uncertainty SI traceability route
Luminous intensity Group of primary standard photometers and auxiliary devices Iv = (10.1000) cd 0,7% INM
Luminous flux Group of special lamps and auxiliary devices Fv = (500.1 200) (lm) 1,0 % BIPM
Radiant power Trap radiometer and auxiliary devices P = 100 nW 10 (mW)
? = (400900) nm
0,25 % LCM
CNAM-LNE
(France)
Spectral transmittance Spectrophotometric absolute installation t = (0,001 1,0) (unu)
? = (200900) nm
(1,00,3) % INM
Spectral reflectance Spectrophotometric absolute installation ? = (0,850,98) (unu)
? = (380850) nm
0,0025 INM

Participation in R&D projects

Most of the national standards owned by the Optical Quantities Group are of own design and construction, achieved in the frames of R&D applied projects. The national standards of Luminous intensity, Spectral transmittance and Spectral reflectance, Radiant Power, are developed within R&D National Programmes or in the frames of self-financing projects. The Maintenance works (characterization, modernization, participation in international comparisons) run in the frames of the applied R&D program Maintaining the national, primary and reference measurement standards of Romania financed by RBLM and NIM.

Participation in comparisons in order to to demonstrate the calibration capabilities

To obtain national and international recognition of calibration capabilities (CMC) implicitly of the calibration services provided to beneficiaries, Optical Quantity Group participated and continues to participate in many international comparisons, most of them key and supplementary comparisons within the CIPM-MRA:


Calibration capabilities and Units dissemination

Units dissemination is accomplished through a variety of calibrations, the main capabilities being recognized in accordance with the requirements of CIPM-MRA (www.bipm-org/MRA) and published in Appendix C of the bank's key comparisons and supplementary data (www.bipm.org/kcdb).

CIPM-MRA recognition implies that calibration certificates issued for these types of calibrations are recognized both by all NIMs affiliated to CIPM-MRA process and by certification and accreditation bodies affiliated to the ILAC, EA and other supervision and regulation bodies. To be seen the section QUALITY MANAGEMENT SYSTEM of this site.

For the full list of calibrations and charges, see the List of measuring means for which the Romanian Bureau Legal Metrology performs calibrations, LE 2016.

 

Personnel, positions and contact details:

PhD Eng. Mihai SIMIONESCU, head of laboratory, tel. (004021) 334.48.30 ext. 117, e-mail: simionescu@inm.ro
Tehn. Hermina Laura CONIA, tel. (004021) 334.48.30, ext. 150
Tehn. Tantica CALOIAN MOISA, tel. (004021) 334.48.30, ext. 150

 


    THERMOMETRY LABORATORY

       

The laboratory was created in 1951, under the name Laboratory of Thermal Quantities and, after successive reorganizations, became the Thermometry Laboratory in 2003, consisting of two specialized Groups:

Activities  

  • Development and maintenance of national references - national and reference standards - of units of temperature and calorific value and assurance of their traceability to SI in the CIPM-MRA process
  • Dissemination of the two units of measurement, at the required accuracy level, by its calibration services
  • Development of techniques and devices in the area of thermal measurements, including uncertainty of measurement analyses
  • Participation in international, regional and bilateral comparisons
  • Cooperation with other relevant institutions in Romania and with similar institutes from abroad
  • Delivery of consultancy and training in issues related to the theory and practice of measurement
  • Pattern evaluations and metrological verifications.

The laboratory performs calibrations and issues calibration certificates that fulfil the requirements of standard SR EN ISO/CEI 17025/2001.

 

TEMPERATURE GROUP

 

Measurement standards 

The International Temperature Scale of 1990 (ITS-90) 

Temperature or, more precisely, thermodynamic temperature, is one of the seven base physical quantities on which the International System of Units (SI) is based. The unit of measurement for thermodynamic temperature is the kelvin, symbol K, defined as the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.

The concept of temperature is defined according to the principles of thermodynamics, using a scale with a single fixed point. This temperature scale was proposed by William Thomson (Lord Kelvin) in 1854 and is known as the thermodynamic temperature scale.

However, the measurement of temperature according to the definition of the fundamental scale requires procedures and thermometers that are difficult to use, and the results are neither accurate, nor reproducible enough.

This led to the necessity to establish a practical scale for international use, where temperature measurements are made easier, are more precise, and are highly reproducible.

Currently, the International Temperature Scale of 1990 (ITS-90) is in use. It evolved from a series of five previous practical international temperature scales, revised and improved approximately every 20 years.

ITS-90 defines the International Kelvin Temperatures, symbol T90 but, for historical reasons, the International Celsius Temperatures, symbol t90 is also used:

[image]t90 / ºC = T90 / K–273,15.

 

As for the previous scales, ITS-90 has been constructed in such a way that every numerical value of T90 is a close approximation to the numerical value of thermodynamic temperature

 

 

 

 

 

The International Temperature Scale of 1990: 

  • is based on a series of defining fixed points
  • uses four means of interpolation and extrapolation
    • vapour pressure thermometer
    • gas thermometer
    • platinum resistance thermometer
    • radiation thermometer
  • calibrated at one or more fixed points; based on these calibrations and using the interpolation equations specified in ITS-90, the entire temperature range of the scale is determined, from 0.65 K to the highest temperature that can be measured in terms of the Planck radiation law.

Fixed points are reproducible equilibrium states of very pure substances that have defined temperatures: triple points, melting points and freezing points. The triple point is the temperature at which the solid, liquid and gaseous phases of a substance coexist in thermal equilibrium at the vapour pressure of the substance. The melting point and freezing point are the transition temperatures of a substance from solid to liquid and from liquid to solid, respectively, at a pressure of 101 325 Pa.

 

National temperature references

The Thermometry Laboratory Temperature Group of INM has developed the national temperature references in the most usual range, between -200 C and 2 200 C, and ensures the traceability of their values to the ITS-90 and to the SI.

The national temperature scale is made using:

  • contact thermometry
  • radiation thermometry

•In the field of contact thermometry, the laboratory has designed and built, based on many years of research and development work, all the fixed defining points of ITS-90 from -189 C to 1 085 C (Table 1).

Table 1

T90 /K t90 /ºC Defining fixed points
83,8058 -189,344 2 Triple point of argon
234,3156 - 38,834 4 Triple point of mercury
273,16 0,01 Triple point of water
302,9146 29,764 6 Melting point of gallium
429,7485 156,598 5 Freezing point of indium
505,078 231,928 Freezing point of tin
692,677 419,527 Freezing point of zinc
933,473 660,323 Freezing point of aluminium
1 234,93 961,78 Freezing point of silver
1 357,773 1 084,62 Freezing point of copper

 

  • Between -189 C and 420 C, the laboratory realizes the ITS-90 according to its definition. The national standard consists of:
  • sealed cells and related equipment - cryostats and furnaces made in the laboratory for the realization of the fixed points
  • a group of standard platinum resistance thermometers (SPRTs)
  • standard resistors and two high precision thermometry bridges a direct current comparator Guildline bridge, model 9975 and an a.c. ASL F18 bridge
  • From 420 C to 1 085 C, the national standard for the unit of temperature consists of:
  • apparatus for the realization of the defining fixed points of ITS-90
  • a group of reference S-type thermocouples, also developed in the laboratory
  • a microvoltmeter and a DC electric potentiometer type P 345

Although the laboratory does not realize the ITS-90 according to its definition in this range, the provided level of accuracy meets the requirements that exist in Romania.

 

• In the field of radiation thermometry, the national temperature scale is realized with a linear monochromatic photoelectric pyrometer, traceable to the PTB, which is the reference measurement standard of Romania from 800 C to 2200C

 

Development and Maintenance Projects for National References

INM's mission to develop and to maintain the national standards sets the priorities for the laboratory's research projects:

Activities for the development of national references:

  • [image]Extending the national temperature standard to the triple point of Ar (-189,344 2C): The laboratory has recently built an apparatus for the realization of the triple point of argon, using the constant flux method after the model of BNM-INM/CNAM (France). It allows the range of the national temperature standard to be extended to -189 C.
  • Realization of the ITS-90, according to its definition, in the range between 420 C and 2 200 C: In the short term, the laboratory intends to realize the national temperature standard at primary level in the range from 420 C to 962 C. For this purpose, the quality of fixed points will be improved and high temperature standard platinum resistance thermometers (HTSPRTs) will be used, as these are the interpolation means specified in the ITS-90. Using HTSPRTs instead of reference S-type thermocouples will cause the accuracy of the national standard to increase at least tenfold. In the medium term, the laboratory intends to obtain the primary measurement standard for temperatures above 962 C, by developing blackbodies at the freezing points of silver (961,78 C) and copper (1084,62 C), defining fixed points of ITS-90 in radiation thermometry.
  • Automating the processes for the realization of fixed points, for measurement, data acquisition and processing: In order to maintain the accuracy level required for working with the national standard, the processes for the realization of the fixed points, for measurement, data acquisition and processing are being automated. This will lead to increased efficiency and will enable us to apply advanced statistical tools.

 

[image]Activities for the maintenance of national standards:  

The laboratory periodically performs activities for the maintenance of national standards, consisting of:

  • characterizing the apparatus for the realization of the fixed points,
  • calibration at the fixed points of the group of standard platinum resistance thermometers and the group of reference S-type thermocouples,
  • identifying possible sources of uncertainty of measurement and evaluating their influence on the results of measurement.

The laboratory is studying new methods for the evaluation of uncertainties, based on comprehensive models, which would integrate all the quantities and parameters identified as possible factors of uncertainty of measurement. The quantitative analysis is done both for fixed-point calibration uncertainties, and for their propagation in the calibration range. In order to include all the input variables and the correlations between them in the model, original calculation programs have been developed.

 

International cooperation  

Cooperation projects  

  • Project EUROMET 713: "Traceability of the ITS-90 fixed points", bilateral project with CNAM-INM.

 

International and regional comparisons.  

 

Dissemination of the national references values

Dissemination of the national and reference standards values to the reference standards of end users is done by the direct measurement at the defining fixed points or by comparison:

• In contact thermometry, the following standards and equipments are used:

  • a secondary set of cells and apparatus for the realization of the defining fixed points of ITS-90;
  • standard platinum resistance thermometers, reference S-type thermocouples, digital system thermometers, liquid-in-glass thermometers, used as reference for calibration by comparison;
  • liquid nitrogen cryostat and various temperature baths (with alcohol, water, oil, salts or alumina powder), ensuring an environment of uniform and stable temperature for calibration by comparison in the range between - 196 C and 700 C;
  • furnaces of various types, some developed in the laboratory, for calibration by comparison in the range between 300 C and 1 600 C.

• In radiation thermometry are used:

  • variable temperature blackbodies built in the laboratory
  • strip lamps

 

Calibration services

The laboratory offers calibration services:

by direct measurement at the fixed defining points of ITS-90, for:

  •  standard platinum resistance thermometers,
  • reference S-type thermocouples,
  • digital system thermometers.

by comparison, for

  • platinum resistance thermometers,
  • S-type thermocouples,
  • digital system thermometers,
  • liquid-in-glass thermometers,
  • temperature indicators,
  • simulators/calibrators,
  • dry block calibrators,
  • thermometers for monitoring of environmental conditions, including data loggers,
  • on site calibration of climatic chambers, temperature calibration baths, furnaces,
  • strip lamps,
  • radiation thermometers,
  • visual radiation thermometers,
  • other instruments for measuring temperature

 

You can find complete information about these services in the List of measuring means for which the Romanian Bureau Legal Metrology performs calibrations, LE 2016.

 

Personnel, positions and contact details:

PhD Eng. Marius Dumitru NEAGU, head of TEMPERATURE group, tel. (004021) 334.48.30 ext. 184; e-mail: marius.neagu@inm.ro
Eng. Adrian DUMITRIU, tel. (004021) 334.48.30 ext. 164; e-mail: dumitriu@inm.ro
Sing. Miruna CAZAN, tel. (004021) 334.48.30 ext.143
Eng. Cosmin DINU, tel. (004021) 334.48.30 ext. 164
Eng. Andreea MOROSANU, tel. (004021) 334.48.30 ext. 143

 

 

CALORIMETRY GROUP

 

Calorific Value

Solid fuels are complex bodies that include a combustible part, a non-combustible part and water under various forms.

The thermal effect of the combustion of a complex fuel is not a resultant of strictly additive processes; the thermal effects of dissociation reactions, which are endothermic relation, need also be considered. Consequently, the thermal effect of the burning reaction can be determined correctly and within a reasonable accuracy margin only experimentally, with the bomb calorimeter, designed exactly for this purpose, and the corresponding magnitude for this effect, under certain conditions, established as a convention, is named, also as a convention, the calorific value of the fuel.

In the case of gas fuels, the most widely used methods for the determination of calorific value are the one based on the variation of the thermal effect during an isotherm-isobar burning process and the one based on the variation of the burnt gas composition, determined by gas-chromatography. The first method is the basis for most of the calorimeters for fuel gases. The second, indirect method is used to certify the reference materials in gaseous state.

 

Measurement standards

For the metrological testing/calibration/check of calorimeters, calorimetric assemblies and systems for the measurement of calorific value in solid, liquid and gaseous fuels, reference materials (RM) are used, in solid state (example: standard benzoic acid etalon for calorimetry) and gaseous state (mixtures of CH4 /N2 or H2 /N2).

Currently the laboratory has certified reference materials (CRM) in solid state (benzoic acid) and in gaseous state (CH4 /N2 mixtures), used for model approval tests, calibrations and metrological checks of the measuring means in the specified field, as well as solid state standard primary RM (benzoic acid NIST), used for the calibration and certification of CRM in solid state.

 

Traceability

  • Secondary standard scales, traceable to the national mass measurement standard;
  • reference materials traceable to NPL and NIST;
  • chemical substances with purity guaranteed by the manufacturer.

 

Services

Preparation and certification of reference materials for combustion calorimetry:

The laboratory prepares and certifies:

  • Solid state reference material, certified for calorific value (benzoic acid).
  • Gaseous state reference material, certified for calorific value (CH4 /N2 or H2 /N2), in cooperation.

 

Calibration measuring instruments in combustion calorimetry:

  • Isotherm calorimetric assemblies with bomb, for the measurement of calorific value of solid and liquid fuels.
  • Isoperibolic or adiabatic calorimetric systems with bomb, for the measurement of calorific value of solid and liquid fuels.
  • Water flow calorimetric assemblies with for the measurement of calorific value of gaseous fuels.
  • Air flow calorimetric systems for the measurement of calorific value, relative density and Wobbe index of gaseous fuels.
  • Calorimetric bombs used to measure the calorific value of solid and liquid fuels.
  • Calorimetric bombs used to determine the chlorine and sulfur in solid and liquid fuels and in oil products.

 

Realization of measurement instruments for combustion calorimetry:

  • Calorimetric assembly with bomb for measuring the calorific power of fuels.
  • Installation for the determination of chlorine and sulfur in solid and liquid fuels and in oil products, using the calorimetric bomb method.
  • Sub-assemblies of bomb calorimeters (tablet-forming press, oxygen-filling device, calorimetric bomb support).
  • Calibration installation for moist gas meters of water flow calorimeters used to measure the calorific power of gaseous fuels.
  • Calibration vessel for moist gas meters.

 

Personnel, positions and contact details:

PhD Eng. Marius Dumitru NEAGU, head of TEMPERATURE group, tel. (004021) 334.48.30 ext. 184; e-mail: marius.neagu@inm.ro
Ing. Camelia Stratulat, tel. (004021) 334.48.30 ext. 115, 123; e-mail: office@inm.ro
Ing. Ionut ROSU, tel. (004021) 334.48.30 ext. 115; e-mail: office@inm.ro

 

 

 

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