WO2023012742A1 - Procédé d'étalonnage d'un compteur à gaz et compteur à gaz étalonné selon le procédé - Google Patents

Procédé d'étalonnage d'un compteur à gaz et compteur à gaz étalonné selon le procédé Download PDF

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Publication number
WO2023012742A1
WO2023012742A1 PCT/IB2022/057314 IB2022057314W WO2023012742A1 WO 2023012742 A1 WO2023012742 A1 WO 2023012742A1 IB 2022057314 W IB2022057314 W IB 2022057314W WO 2023012742 A1 WO2023012742 A1 WO 2023012742A1
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WO
WIPO (PCT)
Prior art keywords
flow rate
gas meter
measurement
error
gas
Prior art date
Application number
PCT/IB2022/057314
Other languages
English (en)
Inventor
Matteo COMPAGNONI
Original Assignee
Cavagna Group Spa
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cavagna Group Spa filed Critical Cavagna Group Spa
Publication of WO2023012742A1 publication Critical patent/WO2023012742A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F25/00—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume
    • G01F25/10—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume of flowmeters
    • G01F25/15—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume of flowmeters specially adapted for gas meters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F15/00—Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
    • G01F15/02—Compensating or correcting for variations in pressure, density or temperature
    • G01F15/04—Compensating or correcting for variations in pressure, density or temperature of gases to be measured
    • G01F15/043—Compensating or correcting for variations in pressure, density or temperature of gases to be measured using electrical means
    • G01F15/046—Compensating or correcting for variations in pressure, density or temperature of gases to be measured using electrical means involving digital counting

Definitions

  • the present invention relates to a method for calibrating a gas meter and a gas meter calibrated according to the method.
  • Gas meters are commonly used to measure the flow rate of gas flowing through the cross-section of a tube, in which they are installed so as to form the total volume of gas which has flowed through the tube over time.
  • each gas meter is typically specifically configured to measure the flow rate exclusively of a gas or an admixture of gases having a predetermined composition so as to minimize the measurement errors relating to this gas or gas admixture.
  • the technical problem addressed by the present invention is to provide a method for calibrating a gas meter and a gas meter calibrated according to the method which is structurally and functionally configured to at least partially overcome one or more of the disadvantages set out with reference to the indicated prior art .
  • an object of the present invention is to provide a gas meter which allows the flow rate of any admixture of a liquefied petroleum gas to be measured, regardless of the percentage of butane and/or propane and/or other component of the admixture.
  • Another object of the present invention is to provide a gas meter which operates in a reliable and secure manner within a wide range of temperatures and flow rates of the gas.
  • the method for calibrating a gas meter comprises: determining an error of the gas meter in relation to a measurement of a flow rate of butane and an error of the gas meter in relation to a measurement of a flow rate of propane with respect to a reference flow rate; calculating a mean error between the error in relation to the measurement of the flow rate of butane and the error in relation to the measurement of the flow rate of propane; determining correction constants as a function of the mean error; and assigning the correction constants to the gas meter in such a manner that the gas meter is calibrated in order to supply a measurement of a flow rate of a liguefied petroleum gas which contains any percentage of butane and/or propane flowing through the gas meter.
  • the term "mean error” is advantageously intended to be understood to mean a mean between the error relating to the measurement of the flow rate of butane and the error relating to the measurement of the flow rate of propane. It will be understood that, in some embodiments, the mean can be replaced by a different position index, such as, for example, the median. It will be appreciated that, advantageously, the mean error between the error relating to the measurement of the flow rate of butane and the error relating to the measurement of the flow rate of propane allows the meter to be calibrated in an intermediate situation between the two limit cases of an admixture of LPG which is composed substantially only of butane or substantially only of propane .
  • the difference between the measurement errors of the flow rate of butane and the corresponding measurement errors of the flow rate of propane always remains less than the value of the tolerance range allowed by the applicable standards for the measurement errors.
  • the difference between the mean error relating to butane and the mean error relating to propane is substantially 2%. Therefore, the mean between the mean error for butane and the mean error for propane is maintained equidistant from the mean error for butane and the mean error for propane at substantially 1%. In this manner, it is ensured that, for any percentage of butane and/or propane in the LPG admixture to be measured, the meter is calibrated so as to provide a measurement of the flow rate with an error within the tolerance range allowed by the applicable standards.
  • the plurality of reference flow rates comprise six reference flow rates. It will be understood that the number of reference flow rates may be different from six, may be at least six or may be exactly six.
  • the plurality of reference flow rates comprises: a first reference flow rate, preferably equal to substantially 0 m 3 /h; a second reference flow rate, preferably equal to substantially 0.016 m 3 /h; a third reference flow rate, preferably equal to substantially 0.25 m 3 /h; a fourth reference flow rate, preferably equal to substantially 0.6 m 3 /h; a fifth reference flow rate, preferably equal to substantially 2.4 m 3 /h; and a sixth reference flow rate, preferably equal to substantially 6 m 3 /h.
  • the plurality of reference temperatures comprise three reference temperatures. It will be understood that the number of reference temperatures may be different from three, may be at least three or may be exactly three.
  • the plurality of reference temperatures comprise: a first reference temperature which is preferably between -30°C and -20°C, even more preferably equal to substantially -25°C; a second reference temperature which is preferably between +15°C and +25°C, even more preferably equal to substantially +20°C; and a third reference temperature which is preferably between +45°C and +65°C, even more preferably equal to substantially +55°C.
  • this reference temperature is unique.
  • the reference temperature for measuring the flow rate of air is between +15°C and +25°C, even more preferably it is equal to substantially +20°C. It will be appreciated that, advantageously, the value of the reference temperature for measuring the flow rate of air corresponds to the value of the second reference temperature for measuring the flow rate of butane and propane.
  • lookup table is intended to be understood to be an information data structure, generally an array, which allows the association of any permissible combination of data being input (ranges of interest of flow rate and temperature) with a corresponding configuration of data being output (the correction constants) .
  • lookup tables allow the replacement of runtime calculation operations with a simpler automatic consultation operation by the meter, advantageously reducing the processing times. It must be observed that, advantageously, there is provision for permanently assigning the correction constants to the gas meter. This solution prevents any change of the correction constants, preventing any accidental modifications of or attempts to tamper with the gas meter following the calibration of the meter itself.
  • the present invention relates to a gas meter which is calibrated to supply a measurement of a flow rate of a liquefied petroleum gas which contains any percentage of butane and/or propane flowing through the meter itself according to the abovementioned method.
  • the gas meter comprises a sensor for measuring an instantaneous flow rate of the gas flowing through the meter itself
  • the term "instantaneous flow rate” is intended to be understood to mean the value of the flow rate which is read by the measurement sensor and which is intended to be corrected subsequently by means of a compensation algorithm of the meter.
  • the gas meter further comprises a processing unit which is operationally connected to the sensor for measuring the instantaneous flow rate and storage means which are accessible to the processing unit.
  • the storage means keep the correction constants stored and comprise instructions which can be carried out by the processing unit which, when they are carried out, cause the processing unit to interpolate (preferably in a linear manner) the correction constants so as to determine a compensation coefficient as a function of the instantaneous flow rate and the temperature of the gas flowing through the gas meter, and to multiply with each other the instantaneous flow rate and the compensation coefficient in order to supply a measurement of the flow rate of the liquefied petroleum gas flowing through the meter.
  • the firmware of the meter is configured to carry out a compensation algorithm for measuring the flow rate of the gas flowing though the meter.
  • the storage means include a non-volatile memory and the correction constants are stored permanently in the nonvolatile memory.
  • the correction constants are stored in the form of lookup tables and the instructions which can be carried out by the processing unit, when they are carried out, cause the processing unit to extract the correction constants to be interpolated from the lookup tables as a function of the instantaneous flow rate and the temperature of the liquefied petroleum gas flowing through the gas meter.
  • Three lookup tables are preferably provided, each lookup table being defined at a specific reference temperature.
  • the meter is suitable for supplying a measurement in a wide range of flow rates and temperatures of the gas.
  • the gas meter includes means for measuring the temperature of the gas flowing through the meter.
  • the processing unit is operationally connected to the means for measuring the temperature of the gas so as to be able to extract the correction constants as a function of the measured temperature from the lookup tables and subsequently to interpolate them.
  • the senor for measuring the instantaneous flow rate is of the ultrasonic type.
  • This solution allows any mechanical anomalies connected, for example, with wear phenomena, to be prevented to the advantage of the service-life of the meter and the stability of the measurements over time.
  • the ultrasonic sensor ensures maximum accuracy, silence and reduced weight.
  • FIG. 1 is a schematic view of the gas meter according to the invention.
  • Figure 3 represents a table for calculating the values of the lookup tables of Figure 2;
  • Figure 6 represents a diagram of a consultation of the lookup tables of Figure 2.
  • a gas meter preferably of the type supplied by battery and suitable for domestic use.
  • the gas meter 1 comprises a sensor 2 for measuring an instantaneous flow rate Q of the gas flowing though the meter itself.
  • the senor 2 is of the ultrasonic type, preferably comprising an ultrasonic tube which is configured to receive a flow of the gas to be measured.
  • the gas meter 1 further comprises a processing unit 3 and storage means 4 which are accessible to the processing unit 3.
  • the instantaneous flow rate Q set out by the sensor 2 is used as a measurement variable in order to supply the measured flow rate Qm.
  • the term "measured flow rate” is intended to be understood to be a value of the flow rate of the gas flowing through the meter 1 which is obtained from the value of the instantaneous flow rate Q which is read by the sensor 2 and which is subjected to a correction or compensation which takes into account the temperature of the gas and any systematic errors and/or offset errors which are connected with the production process of the meter 1 and, in one aspect, with the production process of the ultrasonic tube of the meter itself.
  • the gas meter 1 comprises means 5 for measuring a temperature Tf of the gas flowing through the meter itself.
  • the means 5 for measuring the temperature Tf are integrated in the ultrasonic tube.
  • the compensation coefficient K serves to correct the instantaneous flow rate Q which is read by the sensor 2 as a function of the temperature Tf and/or as a function of any systematic errors and/or offset errors which are connected with the production process of the meter 1 and, in one aspect, with the production process of the ultrasonic tube of the meter itself.
  • the compensation coefficient K is determined from a plurality of correction constants K_T as a function of the instantaneous flow rate Q and the temperature Tf of the gas flowing through the gas meter 1.
  • the correction constants K_T are specific for each gas meter 1 and are assigned to the gas meter 1 during the calibration so as to overcome any systematic errors and/or offset errors which are connected with the production process of the meter 1 and/or of the ultrasonic tube of the meter itself.
  • the calibration of the gas meter 1 provides for the meter 1 to be assigned different correction constants K T corresponding uniquely to different reference flow rates Qr and different reference temperatures Tr so as to calibrate the meter 1 for a wide range of use.
  • the storage means 4 include a non-volatile memory in which there are stored the correction constants K T which result from the calibration of the meter 1.
  • the compensation algorithm provides for the processing unit 3 of the meter to determine the compensation coefficient K for interpolation (preferably, by linear interpolation) of the correction constants K_T as a function of the instantaneous flow rate Q and the temperature Tf of the gas flowing through.
  • the correction constants K_T are not able to be changed or modified in any manner.
  • the gas meter can be calibrated in order to measure a gas to be selected from a natural gas and a liquified petroleum gas (LPG for short) .
  • the correction constants K T assigned to the meter are tabulated in one or more lookup tables and, depending on the case, the calibration provides for one or more lookup tables specific to measuring natural gas or measuring LPG to be assigned to the meter 1.
  • each of the three lookup tables LUT1, LUT2, LUT3 is defined at a specific reference temperature Tr which, in a preferred embodiment, is equal to substantially -25°C, +20°C and +55°C.
  • lookup tables for measuring LPG there are preferably exactly three lookup tables for measuring LPG. It will be understood that, in some embodiments, the number of lookup tables for measuring LPG may be less than three (therefore, one or two lookup tables) so as to simplify the consultation procedure, or may be greater than three
  • the correction constants K T are set out in each of the three lookup tables LUT1, LUT2, LUT3 for different reference flow rates Qr.
  • a single set of different reference flow rates Qr which is identical for each of the three lookup tables is provided.
  • the correction constants K_T are calculated and fixed uniquely during the calibration of the gas meter 1 on the basis of data and measurements carried out in laboratories on one or more reference meters.
  • the correction constants K_T are formed as a function of an error of the gas meter 1 in relation to a measurement of a flow rate with respect to a reference flow rate Qr .
  • the correction constants K_T are formed by the difference Aair/lpg between a mean error Elpg of the meter 1 with respect to the measurement of a flow rate of LPG and a mean error Eair of the meter 1 with respect to the measurement of a flow rate of air, as described in greater detail below.
  • error is intended to be understood to be an error (preferably a mean error) of the meter 1 with respect to the measurement of a flow rate of a gas flowing through the meter 1 as defined with respect to a reference flow rate Qr measured by a reference meter.
  • the mean error Elpg of the meter 1 in relation to the measurement of a flow rate of LPG is calculated using means between a mean error of the meter 1 in relation to the measurement of a flow rate of butane and a mean error of the meter 1 in relation to the measurement of a flow rate of propane.
  • the meter is calibrated so as to provide a measurement of the flow rate with an error which is within the tolerance range permitted by the standards applicable.
  • curve is intended to be understood to be the whole of the errors of the gas meter 1 in relation to the measurement of the different reference flow rates Qr (preferably 0 m 3 /h, 0.016 m 3 /h, 0.25 m 3 /h, 0.6 m 3 /h, 2.4 m 3 /h and 6 m 3 /h) at a given reference temperature Tr.
  • correction coefficients K_T set out in the lookup tables LUT1, LUT2, LUT3 of Figure 2 are calculated from the mean errors Elpg, Eair which are tabulated in Figure 3.
  • K_T 1/ (l+Aair/lpg/100) where Aair/lpg denotes the difference as a percentage error between the curve for air and the curve obtained from the mean between the mean curve for butane and the mean curve for propane at each of the reference temperatures Tr and flow rates Qr indicated in the table of Figure 3.
  • mean curve is intended to be understood to be the curve obtained from the mean of the values collected during the different measurements.
  • the gas meter 1 is suitable for measuring both natural gas and LPG. It will be understood that, preferably, the calibration of the meter provides correction constants K_T and relative lookup tables which are different and specific for selectively measuring natural gas or LPG, respectively.
  • the calibration of the meter 1 provides for selecting an operating mode for the meter 1 which may be selected from an operating mode exclusively with natural gas and an operating mode exclusively with LPG.
  • the default operating mode is the operating mode with natural gas.
  • the default operating mode with natural gas can be modified (in order to instead select the operating mode with LPG) one single time in the life of the meter 1 during the calibration and then can no longer be modified.
  • the calculation of the measured flow rate Qm in the operating mode with natural gas provides for multiplying the instantaneous flow rate Q by the compensation coefficient K obtained directly by the linear interpolation of the correction constants K_T with respect to a lookup table for natural gas while the calculation of the measured flow rate Qm in the operating mode with LPG provides for multiplying the instantaneous flow rate Q by the compensation coefficient K which is updated by means of the compensation algorithm which makes use of the lookup tables LUT1, LUT2, LUT3 for LPG.
  • the ultrasonic tube by providing the temperature Tf of the gas, allows a temperature range of interest to be established. Consequently, the two lookup tables which correspond to the upper extreme and lower extreme of the above-mentioned range are considered.
  • the temperature Tf measured by the ultrasonic tube is equal to 30°C.
  • the lookup tables to be considered are the ones corresponding to +20°C (lower limit of the range of interest) and +55°C (upper limit of the range of interest) .
  • the calculation of the first compensation constant is the first operation carried out by the compensation algorithm in the course of the compensation of a measurement of the gas flow rate, regardless of the temperature Tf.
  • the compensation algorithm carries out a second linear interpolation.
  • the second linear interpolation thereby provides a second compensation constant . At this point, there are two compensation constants (the first compensation constant and the second compensation constant) corresponding to two different temperatures.
  • the compensation coefficient K which serves to multiply the instantaneous flow rate Q in order to supply the measured flow rate Qm will therefore be given by the linear interpolation of the first compensation constant and the second compensation constant.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Measuring Volume Flow (AREA)
  • Details Of Flowmeters (AREA)

Abstract

L'invention concerne un procédé d'étalonnage d'un compteur à gaz comprenant les étapes suivantes : la détermination d'une erreur du compteur à gaz en relation avec une mesure d'un débit de butane et d'une erreur du compteur à gaz en relation avec une mesure d'un débit de propane par rapport à un débit de référence ; le calcul d'une erreur moyenne de ces erreurs ; la détermination de constantes de correction en fonction de l'erreur moyenne ; et l'affectation des constantes de correction au compteur à gaz de telle sorte que le compteur à gaz soit étalonné de manière à fournir une mesure d'un débit d'un gaz de pétrole liquéfié qui contient un pourcentage quelconque de butane et/ou de propane.
PCT/IB2022/057314 2021-08-06 2022-08-05 Procédé d'étalonnage d'un compteur à gaz et compteur à gaz étalonné selon le procédé WO2023012742A1 (fr)

Applications Claiming Priority (2)

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IT102021000021407 2021-08-06
IT202100021407 2021-08-06

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WO2023012742A1 true WO2023012742A1 (fr) 2023-02-09

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117490809A (zh) * 2023-12-19 2024-02-02 成都秦川物联网科技股份有限公司 用于智慧生产的超声波燃气表测试方法及工业物联网系统

Citations (6)

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Publication number Priority date Publication date Assignee Title
EP1182431A1 (fr) * 1999-03-17 2002-02-27 Matsushita Electric Industrial Co., Ltd. Debitmetre a ultrasons
WO2004001516A1 (fr) * 2002-06-24 2003-12-31 Mks Instruments, Inc. Appareil et procede permettant de reguler un debit massique insensible a une fluctuation de pression
US20050034532A1 (en) * 2003-08-14 2005-02-17 Wible Eric J. Dynamic mixed gas flowmeter
US7000463B1 (en) * 2004-11-12 2006-02-21 Mks Instruments, Inc. Reynolds number correction function for mass flow rate sensor
US20140377678A1 (en) * 2012-01-23 2014-12-25 Jx Nippon Oil & Energy Corporation Fuel supply system, fuel cell system, and method for running each
US20160131511A1 (en) * 2013-08-28 2016-05-12 Horiba Stec, Co., Ltd. Fluid Analysis Device, Thermal Flowmeter, Mass Flow Controller, Fluid Property Specification Device, and Program Recording Medium With Program for Fluid Analysis Device Recorded Thereon

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1182431A1 (fr) * 1999-03-17 2002-02-27 Matsushita Electric Industrial Co., Ltd. Debitmetre a ultrasons
WO2004001516A1 (fr) * 2002-06-24 2003-12-31 Mks Instruments, Inc. Appareil et procede permettant de reguler un debit massique insensible a une fluctuation de pression
US20050034532A1 (en) * 2003-08-14 2005-02-17 Wible Eric J. Dynamic mixed gas flowmeter
US7000463B1 (en) * 2004-11-12 2006-02-21 Mks Instruments, Inc. Reynolds number correction function for mass flow rate sensor
US20140377678A1 (en) * 2012-01-23 2014-12-25 Jx Nippon Oil & Energy Corporation Fuel supply system, fuel cell system, and method for running each
US20160131511A1 (en) * 2013-08-28 2016-05-12 Horiba Stec, Co., Ltd. Fluid Analysis Device, Thermal Flowmeter, Mass Flow Controller, Fluid Property Specification Device, and Program Recording Medium With Program for Fluid Analysis Device Recorded Thereon

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117490809A (zh) * 2023-12-19 2024-02-02 成都秦川物联网科技股份有限公司 用于智慧生产的超声波燃气表测试方法及工业物联网系统
CN117490809B (zh) * 2023-12-19 2024-03-26 成都秦川物联网科技股份有限公司 用于智慧生产的超声波燃气表测试方法及工业物联网系统

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