Diaphragm Gas Meter Research Articles

Selecting new products by the revised ideal ratio: a Kano model approach

PurposeThis paper aims to revise the ideal ratio for selecting new products based on their qualitative analysis of desired/undesired functions.Design/methodology/approachThe Kano model has been integrated with the ideal ratio to select and prioritize the design of new products. First, the functional analysis method in value engineering was used to determine the attributes and functions of each product design. Then, the Kano model was used to determine the type of each product attribute and to use the desirable functions of attractive attributes, one-dimensional, must-be and undesirable functions of reverse attributes in the ideal ratio to select and prioritize the design of the product. To examine the application of the proposed approach, a gas instruments manufacturing company was investigated, and five new products were selected for the study.FindingsBased on the results, the product design of industrial regulator GS 77/22 was selected as the superior product and the digital diaphragm gas meter, ultrasonic gas meter, axial regulator and turbine gas meter had the second to fifth priority, respectively.Practical implicationsThe proposed method can help product designers determine product designs suitable for customers' expectations and provide a desirable prioritization of the product design in terms of their ideal ratio according to the customers.Originality/valueThe proposed approach provides a more desirable prioritization compared with other prioritization methods based on customers' viewpoints. In the proposed method, the Kano model results in respecting customers, understanding community needs, respecting consumers' rights and increasing the organization's social responsibility, which will significantly increase the chance of product success in the market.

Mechanical, thermal and morphological properties of polyoxymethylene nanocomposite for application in gears of diaphragm gas meters

Abstract Polyoxymethylene (POM) gears have significant roles in the accuracy, robustness and stability of diaphragm gas meters. Therefore, in an attempt to enhance the properties of POM, four different POM-Cloisite 20A nanocomposites were produced in this study. Later tensile and bending strengths, hardness and Vicat softening temperature test, TGA, DSC, SEM and XRD were employed to experimentally evaluate, compare and contrast the mechanical, thermal and morphological properties of those nano-composites. The results proved that proper melt-mixing of 1% nanoparticle into the polymer matrix could lead to an exfoliated nanocomposite that enhanced the mechanical properties (Young’s modulus, yield stress, tensile and bending strengths and hardness) more than the other samples; however it reduced the degradation temperature. Finally, it did not significantly affect the melting temperature. These experimental results provide promising indications that the nano-based POM gears can exhibit better mechanical properties; hence ensuring an extended and robust performance of diaphragm gas meters.

Illegal gas consumption – general characteristics

Gas billing is always accompanied by unaccounted-for gas loss (UAG) which must be taken into account by gas operators. Gas theft is one of the sources of UAG in the gas distribution area and can be as high as several percent of revenues from gas supplies. The operator should have effective tools to prevent theft, both by detecting and combatting it. Gas companies try to prevent and detect gas theft using various methods. One of them is the continuous control of gas consumption at individual gas consumption points. The gas operator can thus minimize gas losses due to the use of faulty gas meters and gas losses due to leaks caused by third parties. The use of wireless communication technology in measuring devices and the connection of gas meters in smart networks enables the monitoring of gas meters and dynamic data transfer from the measuring devices. Any unauthorized interference with the gas network, gas installation or measurement system may pose a threat to human life and health, and illegal consumption of gaseous fuel is prohibited and is subject to criminal enforcement. The issues of illegal gas consumption have been defined in Polish law, first of all in the Energy Law, and in regulations concerning inspections by energy companies, on determining the scope and amount of fees for illegal consumption of gaseous fuels, and on detailed conditions for the operation of the gas system. The most widely used gas meter for measuring the volume of gas consumed in households is the diaphragm gas meter, which is usually equipped with a mechanical index, but in recent times the use of an electronic index has become more and more popular. The publication specifies several basic types of interference with household diaphragm gas meters, including the measurement system, the index, through the interaction with neodymium magnets, as well as by bypassing the measuring device. The most common are interventions by damaging the security seals and disassembling the gas meter index, followed by a change of indication or tampering resulting in false readings. It has been pointed out that the basic factor for limiting illegal gas consumption as a result of manipulation with the measuring device is ensuring the proper construction of gas meters, including equipping the gas meters with an electronic index with remote communication.

Experimental Assessment of Gas Static Meters Under Different Operating Conditions

This paper compares the metrological performance of a sample of commercial domestic/residential smart meters for natural gas (G4). In particular, the performance degradation of electronic static and dynamic gas meters has been evaluated. The sample was composed by ultrasonic gas meters, thermal mass meters and diaphragm gas meters. The tests, performed on the gas meters, reproduce the most severe operating conditions (i.e. filed test) such as the influence of the gas composition, the temperature difference between gas and meter, the gas humidity and the presence of dust in the gas. Furthermore, the meters have been undergo to some endurance tests such as start and stop and to the high flowrate runs.

Influence of neodymium magnet field on fuel gas metering with diaphragm gas meters

The article deals with the problem of illegal fuel gas consumption among individual consumers in households, especially with regard to gas theft using neodymium magnets attached to diaphragm gas meters. First, the author presents a historical outline of the use of neodymium magnets for the purpose of illegal consumption of fuel gas. The current legal status regarding the requirements for gas meters resistance to tampering and the activities of the Oil and Gas Institute – National Research Institute (INiG – PIB) and Distribution System Operators aimed at eliminating the possibility of illegal gas consumption with the use of neodymium magnets were discussed. Currently possible methods of confirming gas theft using gas meters exposed to the magnetic field of neodymium magnets were presented. Next, the methods of performing at the INiG – PIB laboratory expert examinations of gas meters suspected to be used for illegal gas consumption after their removal from the distribution network were described, and the criteria for assessing these gas meters were given. Based on the expert examinations of gas meters carried out at the Laboratory of Flow Metrology INiG – PIB in the years 2006–2020, a summary of the share of gas meters tampered with the use of neodymium magnets and gas meters with an increased remanence level was presented in relation to performed in a given year expert examinations of gas meters suspected to be used for illegal gas consumption. The methods of counteracting the theft of fuel gas with diaphragm gas meters tampered with the use of neodymium magnets were shown. It has been proved that at present the EC type examination certificate (MID Directive) and the certificate of compliance with the requirements of EN 1359 or OIML R 137-1 & 2 specification do not confirm gas meters resistance to gas theft involving the use of a strong magnetic field. Requirements for new diaphragm gas meters in terms of their resistance to neodymium magnets were presented, and updated criteria for the evaluation of the test results of gas meters exposed to these magnets were given. Finally, a conclusion was proposed regarding the necessity to include provisions on the resistance of diaphragm gas meters to magnetic field in the relevant normative documents for gas meters in order to provide a systemic safeguard for the parties to fuel gas supply contracts.

Impact of environmental and installation conditions on the heat exchange process in selected industrial diaphragm gas meters

Since 2016, Oil and Gas Institute – National Research Institute (INiG – PIB) has been conducting new research to determine the relationship between ambient temperature and gas temperature in industrial diaphragm gas meters during the measurement, and to develop new recommendations for billing systems using industrial diaphragm gas meters with a throughput of until 25 m3/h. In the first stage, work was carried out, in which the obtained test results confirmed that the heat exchange process in an industrial diaphragm gas meter depends on the ambient temperature, the gas temperature at the inlet to the gas meter, the flow rate of the gas flowing, as well as the casing surface and the gas volume of the gas meter. In the next stage, work was carried out to determine the relationship between ambient temperature and gas temperature at the industrial diaphragm gas meter connection during the measurement. The obtained results undermined the thesis, which indicated that the gas inlet temperature is equal to the gas temperature at the depth of the gas network. In the last stage, work was carried out to determine the course of changes in gas temperature in industrial diaphragm gas meters as a function of ambient temperature and cyclical changes of the gas flow rate, which were to reflect the work of gas meters installed at customers’ premises. The analysis of the obtained test results once again showed a strong dependence of the gas temperature inside industrial diaphragm gas meters on the ambient temperature, but also on the flow rate of gas. The obtained results of laboratory tests will be used to carry out a thermodynamic description of the heat exchange process in an industrial diaphragm gas meter, which would allow the determination of the gas billing temperature as a function of the ambient temperature, the temperature of the inflowing gas and the gas flow rate. The calculated gas temperature values could be used to determine the temperature correction factors applicable when settling gas consumers billed on the basis of measurement with the use of industrial diaphragm gas meters.

Study of the Effect of Addition of Hydrogen to Natural Gas on Diaphragm Gas Meters

Power-to-gas technology plays a key role in the success of the energy transformation. This paper addresses issues related to the legal and technical regulations specifying the rules for adding hydrogen to the natural gas network. The main issue reviewed is the effects of the addition of hydrogen to natural gas on the durability of diaphragm gas meters. The possibility of adding hydrogen to the gas network requires confirmation of whether, within the expected hydrogen concentrations, long-term operation of gas meters will be ensured without compromising their metrological properties and operational safety. Methods for testing the durability of gas meters applied at test benches and sample results of durability tests of gas meters are presented. Based on these results, a metrological and statistical analysis was carried out to establish whether the addition of hydrogen affects the durability of gas meters over time. The most important conclusion resulting from the conducted study indicates that, for the tested gas meter specimens, there was no significant metrological difference between the obtained changes of errors of indications after testing the durability of gas meters with varying hydrogen content (from 0% to 15%).

Working Principle of Gas Turbine Meter Fluxi 2000/TZ and Gas Volume Converter

The use of natural gas in several countries, especially in Indonesia is essential. In gas distribution, every industry and household will not be separated from the measurement system that aims to find out how much natural gas has been used. For this reason, the use of a gas flow meter is necessary. There are several types of gas flow meter can be used in measuring the gas volume. Some types of gas flow meters are gas turbine meters, rotary gas meters and diaphragm gas meters. The primary difference of each type of gas flow meter is the pressure capacity and the speed of the gas flow through it. Flow meter gas turbine is one type of gas flow rate measuring device. There are moving parts consisting of a propeller whose rotation speed is proportional to the flow rate through the flow meter. The type of gas turbine meter is Fluxi 2000/TZ. Fluxi 2000/TZ is designed to measure natural gas and various non-corrosive gases. This tool can be used to measure low gas flow and high gas flow. This tool can also be used to measure flow under various pressure conditions. Corus is the name of the type of gas volume converter. Corus is one instrument that supports the reading process of various gas meters, and one of them is a gas turbine meter. Corus is designed to achieve high levels of performance and accuracy from robust electronic equipment so that the results of reading the fluid volume available on the gas turbine meter can be calculated more accurately regard to the amount of temperature, pressure and compressibility. The working principle and characteristics of the two instruments make the measurements more accurate.

Metrological performance of diaphragm gas meters with different use age

According to the current legal metrological regulation of diaphragm gas meter, domestic gas meters in China are required to pass mandatory initial verification at 20°C, and then a 10 years' legal duration is allowed without any subsequent or in-service verifications. Here, experimental study has been implemented to investigate the metrological performance and temperature adaptability of old diaphragm gas meters with different use age. Through the introduction of weighting factors, weighted mean errors are calculated to analyse the correlation between the indication errors of gas meters and their use age, as well as the relationship between the indication errors and test temperatures. Experimental results indicate that the use age of gas meters has negligible influence on their metrological performance during the 10 years' legal duration. However, the indication errors worsen as temperature varies.

An Indirect Measurement Method for Gas Consumption of a Diaphragm Gas Meter Based on Gas Pressure Signal Detection

At present, the remote meter reading problem for a large number of existing domestic diaphragm gas meters has not been reliably solved. The diaphragm gas meter uses a physical structure to measure gas consumption, so the main problem of remote meter reading is the digitization of gas consumption. Although it is possible to digitize the consumption data by modifying the internal structure of the gas meter or adding sensors, thereby realizing the function of remote meter reading, the modification process is complicated, the modification cost is high, and manual meter reading can only be used for the existing diaphragm gas meters. For this reason, this paper proposes an indirect measurement method of gas consumption based on gas pressure signal detection. The method can digitalize the metering results of the mechanical diaphragm gas meter and develop a state detection function by analyzing the pressure signal of the outlet of the meter without modifying the internal structure of a meter, thus addressing the key difficulties in the construction of a gas meter remote meter reading system. The experimental results show that this method has small calculation error and high reliability.

Development of Experimental Apparatus for Diaphragm Gas Meter in the Limiting Temperature Conditions

This paper presents the basic architecture and working principle of diaphragm gas meter experimental apparatus in the limiting temperature conditions. A double-standard test method with critical flow nozzle as main standard and roots flow meter as reference standard has been proposed. Indicating error and pressure loss characteristic at different temperatures are obtained by experimental research on the metrological characteristics of diaphragm gas meters (G2.5) which are produced by numerous corporations under the condition of non-reference temperature. The experimental results show that the indicating value of diaphragm gas meters under high temperatures is basically accurate, but the metrological property is a little patchy in terms of quality at low temperatures. The maximum indication error of part measuring instruments is up to 16%.

Design of the Gas Flow Integrating Instrument

A flow integrating instrument based on the diaphragm gas meter is designed with MSP430 microprocessor. The double reed switch is used for the flow signal acquisition with higher Accuracy. In order to reduce the influence of pressure and temperature on gas flow measurement, the PT1000 resistance temperature sensor and silicon piezo-resistive pressure sensor circuit are designed. The embedded software is developed with C. The experimental result show the flow integrating instrument has high accuracy.

Tightness Detecting Technique for the Valves of Diaphragm Gas Meter Based on Chromatic Confocal Method

Diaphragm gas meter is a specialized flow meter that measures the volume of fuel gas such as natural gas and coal gas. Valve bonnet and valve seat are the key parts of diaphragm gas meter, which compose the main factors of its metering error. The widely detecting ways are direct observational method and pneumatic pressure method. Direct observational method only realizes the qualitative detection with lacking science. Pneumatic pressure method can realize the quantitative detection, but with low accuracy and bad reliability. In order to evaluate the gas tightness of diaphragm gas meter valve accurately, surface texture method was adopted. Firstly, the surface roughness mathematical model of valve working face was established. A fast Gaussian filtering convolution algorithm was proposed based on the symmetry of Gaussian density function. Secondly, the working face of gas valve on the high-precision air floating stage was scanned by the chromatic confocal sensor. And the roughness profile of valve working face was got through the fast Gaussian filter when the cut-off wavelength was 0.8mm. Then the roughness parameters could be calculated with MATLAB by setting the sampling length and evaluation length. The results show that surface roughness has a difference of over 1μm between the qualified and unqualified valve. Besides, there is a little deviation of below 9% between the experimental value and the stylus profilometer measuring value, which has no influence on the judging result of qualified or unqualified about the measured workpiece. The gas tightness performance of gas valve can be judged by measuring surface roughness of its working face, which can provide a scientific basis for evaluating the quality of diaphragm gas meter valve in a quantitative way.

Metrological performance of diaphragm gas meters in distribution networks

In natural gas distribution networks a great number of domestic diaphragm gas meters are currently installed (about 15 million in Italy) and most of them are very old meters. Furthermore, some National Authorities nowadays impose strict roll-out procedures of the existing meters with new smart meters. To this aim, diaphragm meters in “hybrid” configuration equipped with electronic and transmission devices are supposed to be widely installed by natural gas distribution companies in the first roll-out campaigns, since they present a fully developed technology despite of the new ultrasonic and thermal mass meters.In this paper the author presents the results of a wide experimental study aimed to assess how metrological performance of diaphragm gas meters worsen over time as function of age, installation conditions, manufacturing technology, etc.The results of the experimental analysis show that a significant number of the meters investigated failed subsequent verification and presented a not excellent stability. On the other hand, the average percentage errors and the weighted mean error of the meters were measured basically close to zero, also for very old meters.

Research on the Online Verification Instrument for Diaphragm Gas Meter

A novel online verification instrument for diaphragm gas meter based on positive displacement principle is proposed. Through an in-depth research on online verification technology, a dedicated wave absorber is designed to eliminate the effect of pressure pulsation. The whole series of the online diaphragm gas meter verification in normal operation condition is realized by adopting fixed-point calibration and nonlinear correction technology. The experimental data shows that the uncertainty is within 0.5% and the ratio of the measurement range is reach to 100:1.

HIGHLY ACCELERATED LIFETIME TEST METHOD STUDY FOR THE DIAPHRAGM GAS METER RELIABILITY ENHANCEMENT

The present study has been conducted to verify and enhance the MTBF of the diaphragm gas meter. The goals of this study were the development of acceleration test method for the diaphragm gas meter and the guarantee of B10 lifetime of 3000 h in normal operation condition. To develop the acceleration test method, the flow rate and the operation temperature were chosen as acceleration factors and experiments of 1000 h in four conditions are conducted. The results showed that the log-normal life distribution conforms to the diaphragm gas meter life distribution and the combination of the temperature and the flow rate can have the acceleration factor of up to 3.48. The uncertainty of the flow rate accuracy verification is 0.20% and the log-normal life distribution is used.

An experimental intercomparison of gas meter calibrations

This paper presents four calibrations carried out in four different, independent, metrological accredited laboratories, on six diaphragm gas meters for domestic use (G4). The aim of this study is to evaluate the degree of metrological agreement among different calibration results, by means of the assessment of suitable factors (compatibility index, also known as normalized error). This application study is quite interesting in the field of “legal metrology”, when often conformity assessment are requested in order to assure the adequate behavior of a domestic gas meter. The six gas meters were calibrated in four different laboratories, each of them characterized by different values of the calibration uncertainty (also called CMC=Calibration and Measurement Capability, or BMC=Best Measurement Capability, or Minimum Uncertainty). Two alternative approaches about the metrological compatibility are introduced: a quantitative approach and a qualitative approach. The calibration results show that for diaphragm gas meters for domestic use, the metrological agreement should be preferable by means of the qualitative approach.

Final report on intercomparison measurements in the field of gas flow and volume, which are realized at two levels: the second level (B*)

COOMET project no 219/SK-a/00 'Performance of comparison measurements of testing standard equipment working in the gas flowrate range: (A) 0.06 m3/h to 10 m3/h; (B) 100 m3/h to 1000 m3/h', ref. no COOMET.M.FF-S1 has been organized by TC 1.4 'Flow measurement' of COOMET, started in March 2006 and finished in October 2008.Type of comparison – supplementary; Pilot laboratory – SMU, Slovak Institute of Metrology.Participating institutes (and countries): SMU, Slovakia; PTB, Germany; LEI, Lithuania; BelGIM, Belarus; FGUP VNIIR, Russia; SE 'Ivano-Frankovskstandartmetrology', Ukraine; NISM, Moldavia.The comparison was realized at two levels.Within the first level (A*), the comparisons of the test rigs were realized for verification of the diaphragm domestic gas meters in the flow range of 0.12 m3/h to 10 m3/h. The compared measurement means were the set of five diaphragm gas meters of type MKM, size G6. Two laboratories (SMU Bratislava, Slovakia and LEI Kaunas, Lithuania) of the seven participating laboratories at this level are participants in projects of comparisons, which are organized within the regional metrological organization EUROMET.The second level (B*) assured a comparison measurement of testing devices for industry gas meters of flow range from 100 m3/h to 1000 m3/h. The comparison meter was an axial turbine gas meter of DAE type, G650 size serial number 0004455/2005. Seven laboratories participated at this level of the project, including the laboratory of Belarus with a limited flow rate range (from 100 m3/h to 400 m3/h). Three laboratories (PTB Braunschweig, Germany; SMU Bratislava, Slovakia and LEI Kaunas, Lithuania) of the seven participating laboratories at this level are participants of comparisons, which are organized within the regional metrological organization EUROMET; out of that group the laboratory PTB Braunschweig, Germany is also participant in a CIPM key comparison.Based on the given results, one can say that the first comparison in this field within the COOMET regional organization achieved good results.Main text.To reach the main text of this Paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by COOMET, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Final report on intercomparison measurements in the field of gas flow and volume, which are realized at two levels: the first level (A*)

COOMET project no 219/SK-a/00 'Performance of comparison measurements of testing standard equipment working in the gas flowrate range: (A) 0.06 m3/h to 10 m3/h; (B) 100 m3/h to 1000 m3/h', ref. no COOMET.M.FF-S1 has been organized by TC 1.4 'Flow measurement' of COOMET, started in March 2006 and finished in October 2008.Type of comparison – supplementary; Pilot laboratory – SMU, Slovak Institute of Metrology.Participating institutes (and countries): SMU, Slovakia; PTB, Germany; LEI, Lithuania; BelGIM, Belarus; FGUP VNIIR, Russia; SE 'Ivano-Frankovskstandartmetrology', Ukraine; NISM, Moldavia.The comparison was realized at two levels.Within the first level (A*), the comparisons of the test rigs were realized for verification of the diaphragm domestic gas meters in the flow range of 0.12 m3/h to 10 m3/h. The compared measurement means were the set of five diaphragm gas meters of type MKM, size G6. Two laboratories (SMU Bratislava, Slovakia and LEI Kaunas, Lithuania) of the seven participating laboratories at this level are participants in projects of comparisons, which are organized within the regional metrological organization EUROMET.The second level (B*) assured a comparison measurement of testing devices for industry gas meters of flow range from 100 m3/h to 1000 m3/h. the comparison meter was an axial turbine gas meter of DAE type, G650 size serial number 0004455/2005. Seven laboratories participated at this level of the project, including the laboratory of Belarus with a limited flow rate range (from 100 m3/h to 400 m3/h). Three laboratories (PTB Braunschweig, Germany; SMU Bratislava, Slovakia and LEI Kaunas, Lithuania) of the seven participating laboratories at this level are participants of comparisons, which are organized within the regional metrological organization EUROMET; out of that group the laboratory PTB Braunschweig, Germany is also participant in a CIPM key comparison.Based on the given results, one can say that the first comparison in this field within the COOMET regional organization achieved good results.Main text.To reach the main text of this Paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by COOMET, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

In situ detection of inaccurate gas flow meters using a fingerprint technique

This work describes an in situ method for the testing of mechanical flow meters. The method was developed on diaphragm gas meters, but can be applied to most mechanically-based flow meters. The proposed fingerprint method analyses the behaviour of the meter during a work cycle. The result from the analysis is a “fingerprint” of the meter, in which mechanical errors in the meter can be detected. This is explained by the mechanical connection between the sensing mechanism and the mechanical output from the meter. An error analysis of a diaphragm meter was carried out to deduce the type of errors that are likely to occur in such meters. The most severe malfunctions are leakage, internal friction and liquid in the meter. These errors can either lead to measuring errors or can cause the meter to cease functioning. The fingerprint method has been tested on meters with simulated errors and on used meters taken from the gas grid in Lund. The fingerprint method can correctly diagnose errors such as leakage, increased friction and liquid in the meter.