Metrological Assurance of Gas Calorimeter and Wobbe Index Analyser

The paper describes research on metrological assurance of such measuring instruments as gas calorimeters and Wobbe index analysers. The purpose of the performed research is development of reference materials for gases with certified value of net volume-basis calorific value traceable to Russian state primary standard. Input set of candidate gases is hydrogen, methane, ethane and propane, as well as the target uncertainty of lower volumetric combustion energy value equal to 0,3 % – both were selected basing on results of metrological characteristics analysis of calorimetric equipment. The certified value of lower volumetric combustion energy is traceable to the State Primary Standard of combustion energy, specific combustion energy and volumetric combustion energy units GET 16. The certified value of selected gases and the uncertainty of this value were estimated with usage of comparing calorimeters for the combustion of high- and low-calorie gases «USVG» and «USNG» included in GET 16. Results obtained during investigational study and reference materials characterisation confirmed the stated accuracy. The continuance in prospect may allow development of reference materials for gas imitating mixtures of natural and casing-head gases as well as include Wobbe index in the list of certified characteristics.

Development of food industry metrological assurance complex

The paper considers the contribution of experts from the Laboratory of Metrology of Moisture Measurement and Reference Materials to the improvement of the food industry metrological assurance system. The information on the results of the development of forty types of reference materials (RM) for the composition of various nutrition, food staples and nutritional supplement in the period 2008-2020 is generalized. The development of each new RM type included preparation of the material, research for its stability and homogeneity, and determination of certified value with the appliance of State primary (GET 173) and secondary (GVET 176-1) standards, as well as primary reference measurement procedures and conducting the interlaboratory experiment for checking the applicability of the RM. The creation in 2008 of GET 173 was accompanied by the development of RMs for the composition of grains and dry milk product. The approval in 2010 of GVET 176-1 allowed to add in the RM the certified value for the mass fraction of nitrogen (protein). As a result of successful participation in comparisons, UNIIM got 6 items of calibration and measurement capabilities on measurements of mass fraction of nitrogen in glycine, milk powder, grain, egg powder, cereal and feed-stuff in the BIPM database. 35 types of RM for the composition of dairy and meat products, egg powder, infant food, oil and starch products together with the development of primary reference measurement procedures for measurement of fat, crude fat, ash and carbohydrates mass fraction were created between 2016 and 2019. Moreover, the RM for the composition of nutritional supplement (glycine, melamine, cystine) and dairy products for metrological assurance of IR-analysers as well as RM for the composition of reconstituted milk were developed for the control of measurement results by the enzyme-linked immunosorbent assay (ELISA). Developed RM were systemized on fields of the appliance of Technical regulations of Customs Union and the sectors of the international food triangle model. These RMs allow providing the measurement uniformity of the identification indicators and the nutritional value of food products and food staples.

Results of researches for new method for metrological assurance of mass measurements on conveyor weigher

The paper considers the issue related to calibration of conveyor weigher in laboratory environment for its usage as etalon and the subsequent transfer of a unit of linear density from them to the transported means of comparison – the measure of linear density. The equations of the mass flow in instant hopper-conveyor system are got. The algorithm of etalon conveyor weigher calibration is developed on the results of mass measurement in hopper at work process of hopper-conveyor instant system which doesn’t require passing a known fixed mass through a conveyor weigher. The transfer way of linear density unit from etalon conveyor weigher to linear density measure with accuracy required by measurement chain is proposed.

The adjustment suggestions for the GOST R 8.596-20xx “State system for ensuring the uniformity of measurements. Metrological assurance for measuring systems. Main principles”

It’s suggested to adjust the existing normative documents, in particular the first version of GOST R 8.596-20xx “State system for ensuring the uniformity of measurements. Metrological assurance for measuring systems. Main principles”. The aim of the proposed adjustment is to legitimate the nuclear power plants complex measuring systems application, taking into account their peculiarities in the sphere of state regulation of ensuring the unity of measurements. Generally complex measuring systems possess all features of the adaptive and intelligent measuring systems, which parameters and algorithms can vary during operation. Therefore, it is proposed for adaptive and intelligent measuring systems and for branched measuring channels, to provide the possibility of dividing into separate measuring components without the whole system or channel approving. The systems and channels measuring components are proposed to be considered as approval measuring instruments, which interaction is regulated by certified measurement techniques. When selecting the boundaries of the measuring system or channel, it is proposed to provide the possibility to be guided by the reasonability of the sorting the technical means or operations involved in parameter control as metrologically significant. In addition, it is proposed to introduce a statute that allows to avoid the type approving of the “degenerate” systems consisting of one or more simple channels formed only by the measuring means.