초록 ▼

The invention relates to a method and a device for measuring a gas consumption by means of a gas meter. A gas meter with thermal mass flow sensor for determining mass flow signals (SM) and with a calibration as energy meter for outputting energy value signals (SE) is known. According to the inventio

The invention relates to a method and a device for measuring a gas consumption by means of a gas meter. A gas meter with thermal mass flow sensor for determining mass flow signals (SM) and with a calibration as energy meter for outputting energy value signals (SE) is known. According to the invention, a gas type is determined by the gas meter insofar as combustible and non-combustible gas mixtures are differentiated. The gas meter is operated, in the case of a non-combustible gas mixture, with calibration in mass or standard volume units (I/min) and, in the case of a combustible gas mixture, with calibration in energy units (kWh). Embodiments concern inter alia: measurement of a gas parameter (λ, α, c, η) of the gas or determining the gas type; gas quality sensor with an identical construction to thermal flow sensor; measuring intervals lengthened in the case of non-combustible gas and shortened in the case of combustible gas. Advantages are inter alia: reliable energy measurement because of automatic differentiation between non-meterable gas and high-quality useful gas; detection of manipulation attempts; and automatic heat value tracking even without heat value measurement.

대표청구항 ▼

The invention claimed is: 1. A method for measuring a meterable gas energy supply in the private, public or industrial sphere, utilizing sensor signals (S) that are proportional to a flow rate of the gas, the method comprising: determining the signals using a gas meter by means of a thermal flow se

The invention claimed is: 1. A method for measuring a meterable gas energy supply in the private, public or industrial sphere, utilizing sensor signals (S) that are proportional to a flow rate of the gas, the method comprising: determining the signals using a gas meter by means of a thermal flow sensor, the sensor signals (S) being output as at least one of energy value signals (SE) and corrected mass flow rate signals (SM) based on a calibration of the gas meter as energy meter or a mass flow rate meter, wherein: a) a gas type is determined by the gas meter insofar as a non-combustible gas mixture is differentiated from a combustible gas mixture; b) the gas meter is operated with a calibration in mass or standard volume units (1/min) in the presence of a non-combustible gas mixture, and is operated with a calibration in energy units (kWh) in the presence of a combustible gas mixture; c) at least one gas type-dependent parameter of the gas mixture is determined by means of a thermal gas quality sensor; d) the gas mixture is identified as combustible or non-combustible by comparing the at least one gas type-dependent parameter with known values of the parameter for known gases or gas mixtures; e) the thermal flow sensor provides the function of the gas quality sensor, the gas mixture being guided over a first temperature sensor, a heating element, and a second temperature sensor of the thermal flow sensor; and f) the corrected mass flow rate signals (SM) are determined from a difference of temperature signals of the temperature sensors, and the gas type-dependent parameter is determined from a sum of the temperature signals or from the temperature signal of the first temperature sensor alone. 2. The method according to claim 1, wherein: a) the thermal flow sensor determines a measured heat conductivity (λ) as the gas type-dependent parameter, which is tested for correspondence to a heat conductivity value corresponding to 0.0260 W/mK for nitrogen, 0.0263 W/mK for oxygen, 0.0261 W/mK for air, or 0.0168 W/mK for carbon dioxide, a prescribable tolerance of ��10% for each of nitrogen, oxygen, air, and carbon dioxide being taken into account, b) in the case of correspondence, the gas mixture is categorized as non-combustible and a signal output of the gas meter is operated with a scale which is calibrated in mass or standard volume units (I/min), and c) in the case of non-correspondence, the gas mixture is categorized as combustible and a signal output of the gas meter is operated with a scale which is calibrated in energy units (kWh). 3. The method according to claim 1, wherein the parameter is a measured heat capacity (c), which is compared with a threshold value corresponding to an absolute value of 1300 J/kgK, a prescribable tolerance of ��10% being taken into account, b) upon falling below the threshold value, the gas mixture is categorized as non-combustible and a signal output of the gas meter is operated with a scale which is calibrated in mass or standard volume units (I/min), and c) upon exceeding the threshold value, the gas mixture is categorized as combustible and a signal output of the gas meter is operated with a scale which is calibrated in energy units (kWh). 4. The method according to claim 1, wherein a) it is tested periodically whether the gas meter is in contact with a combustible gas, or with a non-combustible gas, in and/or b) measuring intervals for determining sensor signals (S) are chosen to be large, in the presence of a non-combustible gas mixture, and are chosen to be small, in the presence of a combustible gas mixture. 5. The method according to claim 1, wherein a consumed supply of gas energy is integrated in the gas meter; the consumed supply of gas energy is stored intermediately when switching the calibration to mass or standard volume units (1/min); and the consumed supply of gas energy is used as start value when switching the calibration back to energy units (kWh). 6. The method according to claim 1, wherein the corrected mass flow rate signals (SM) are stored in mass or standard volume units (1/min) in the gas meter; and a) the corrected mass flow rate signals (SM) are further incremented when switching the calibration to energy units (kWh); and b) the corrected mass flow rate signals (SM) are stored intermediately, and are used as start values or are set back to zero as a start value when switching back to mass or standard volume units (1/min). 7. The method according to claim 1, wherein: a) the gas meter displays whether it is in contact with a combustible gas, a non-combustible gas, or a combination thereof by means of an indicator or display; b) mass or standard volume units (1/min) are indicated, and energy units (kWh) are indicated only upon a first contact with a combustible gas due to a default setting of the gas meter; c) during assembly, the calibration is switched automatically from mass or standard volume units (1/min) for a non-combustible gas to energy units (kWh) for a combustible gas by means of a first initialization of the gas meter; and d) a manipulation indicator of the gas meter is activated upon contact with a non-combustible gas, then a combustible gas, and then a non-combustible gas again. 8. The method according to claim 1, wherein: a) sensor signals (S) dependent upon the flow rate of a calibration gas are determined for calibrating the gas meter as an energy meter and are stored in the gas meter in the form of a sensor calibration curve (F(S)), the sensor calibration curve (F(S)) being proportional to uncorrected mass flow rate signals (Sm) determined by the thermal flow sensor; b) the corrected mass flow rate signals (SM) are obtained by correcting the uncorrected mass flow rate signals (Sm) with a signal conversion factor; and c) the energy value signals (SE) are obtained from multiplying the corrected mass flow rate signals (SM) with a heat value factor for a basic gas mixture, the energy value signals (SE) indicating a gas consumption in energy units (kWh). 9. A gas meter for measuring a gas consumption according to claim 1. 10. A gas meter for measuring a meterable gas energy supply in the private, public or industrial sphere, the gas meter having a thermal flow sensor that is also used to determine a gas composition of the gas supply, and is calibrated in energy units (kWh) when used as energy meter, wherein: a) the gas meter is calibrated in mass or standard volume units (1/min) when used as a mass flow rate meter; b) the gas meter has a gas quality sensor which generates a discrimination signal, as a function of a gas type-dependent parameter in order to differentiate a combustible gas mixture from a non-combustible gas mixture; and c) the gas meter can be switched between an operation as energy meter or an operation as a mass flowmeter based on the discrimination signal. 11. The gas meter according to claim 10, wherein the thermal flow sensor comprises CMOS anemometers with a heating wire and temperature sensors that are disposed upstream and downstream of the gas flow. 12. The gas meter according to claim 10, wherein a) the thermal flow sensor can function as a gas quality sensor if a measured mass flow rate falls below a prescribable threshold value, or b) the thermal flow sensor is disposed in a region with a constant flow rate. 13. The gas meter according to claim 10, wherein: a) the gas meter has an indicator or a display for gas quality, which comprises the presence of a calibration gas, a combustible gas, a non-combustible gas, or a combination thereof; b) the gas meter has a manipulation indicator that can be activated when the gas changes from a non-combustible gas to a combustible gas, and then back to a non-combustible gas; c) the gas meter has a measuring and evaluating unit for determining energy consumption values (SE) and/or mass flow values (SM); and d) the gas meter has separate data memories for storing energy consumption values (SE) and mass flow rate values (SM).