Abstract: A method includes receiving a gas or gas mixture through a flow sensor. A flow velocity, volumetric, or mass flow are determined. The method also includes determining a sound velocity of the gas or gas mixture by an ultrasonic sensor. A density of the gas or gas mixture is correlated from the sound velocity. The method also includes positioning a microthermal sensor in an area with less flow or no flow of the gas or gas mixture. A thermal conductivity and thermal diffusivity of the gas or gas mixture at the one or more temperatures is determined. The method also includes connecting a processor to the microthermal sensor to calculate an energy of the gas or gas mixture based on a calorific value, the temperature and the volume or mass flow. Specific quantities for gas quality are correlated.

Abstract: A method using a gas reservoir and a critical nozzle for determining physical properties and/or quantities relevant to combustion of gas or gas mixtures, the method includes: flowing a gas or gas mixture under pressure from the gas reservoir through the critical nozzle; measuring pressure drop in the gas reservoir as a function of time; determining a gas property factor (?*), dependent on physical properties of the gas or gas mixture, based on the measured values of the pressure drop; and determining a desired physical property or quantity relevant to combustion based on the gas property factor (?*) through correlation.

Abstract: A method for the combined controlled regulation of fuel gas-oxygen carriers of a gas operated energy converter plant (15), in particular of a fuel cell plant, is provided in which the mass or volume through flow of the fuel gas (1) and/or of the oxygen carrier (2) is detected in order to regulate the mixing ratio (r) of fuel gas to oxygen carrier. In the method at least two physical parameters of the fuel gas are additionally determined using a micro thermal sensor (3.1, 3.2), for example, the mass flow and/or volume through flow of the fuel gas and the thermal conductivity or thermal capacity of the fuel gas are determined and a desired value for the mixing ratio is determined from the physical parameters which depends on the fuel gas or on the composition of the fuel gas, and which desired value is used for the regulation of the mixing ratio.

Abstract: A method in which a gas property (Q) is determined by correlation from physical measuring quantities (?j) of the gas mixtures. In the method, the physical measuring quantities are combined into a sensor output (Sout) by making use of a sensor output function (ƒ), wherein the sensor output function is determined in such a way that a group of gas mixtures can be separated from a set of gas mixtures for which the gas property (Q) is determined, within which the correlation between the sensor output (Sout) and the desired gas property (Q) is better than in the entire set.

Abstract: A method using a gas reservoir and a critical nozzle for determining physical properties and/or quantities relevant to combustion of gas or gas mixtures, the method includes: flowing a gas or gas mixture under pressure from the gas reservoir through the critical nozzle; measuring pressure drop in the gas reservoir as a function of time; determining a gas property factor (?*), dependent on physical properties of the gas or gas mixture, based on the measured values of the pressure drop; and determining a desired physical property or quantity relevant to combustion based on the gas property factor (?*) through correlation.

Abstract: A method to determine a physical property or a quantity of gas related to combustion including: flowing a gas from a reservoir through a critical nozzle and past a microthermal sensor wherein the mass flow of the gas through the critical nozzle is the same as the mass flow through the microthermal sensor; measuring the pressure drop in the reservoir as a function of time; deriving a first gas property factor based on a time constant of the pressure drop; determining a second gas property factor which depends from a flow signal generated by the microthermal sensor; determining a thermal conductivity of the gas; and determining the physical property or quantity based on a correlation between the physical property or quantity, and the first and/or second gas property factors and the thermal conductivity.

Abstract: A method in which a gas property (Q) is determined by correlation from physical measuring quantities (?j) of the gas mixtures. In the method, the physical measuring quantities are combined into a sensor output (Sout) by making use of a sensor output function (ƒ), wherein the sensor output function is determined in such a way that a group of gas mixtures can be separated from a set of gas mixtures for which the gas property (Q) is determined, within which the correlation between the sensor output (Sout) and the desired gas property (Q) is better than in the entire set.

Abstract: A method for determining physical properties of combustion including: flowing a gas a critical nozzle and past a microthermal sensor wherein the mass flow of the gas through the critical nozzle is the same as the mass flow through the microthermal sensor; measuring the pressure drop in a reservoir of gas flowing to the nozzle; determining a first gas property factor based on the measured pressure drop; determining a second gas property factor based on a flow signal generated by the microthermal sensor; determining a thermal conductivity of the gas using the microthermal sensor; and determining a physical property of the combustion based on a correlation of the first and/or second gas property factors and the thermal conductivity.

Abstract: A method for the combined controlled regulation of fuel gas-oxygen carriers of a gas operated energy converter plant (15), in particular of a fuel cell plant, is provided in which the mass or volume through flow of the fuel gas (1) and/or of the oxygen carrier (2) is detected in order to regulate the mixing ratio (r) of fuel gas to oxygen carrier. In the method at least two physical parameters of the fuel gas are additionally determined using a micro thermal sensor (3.1, 3.2), for example, the mass flow and/or volume through flow of the fuel gas and the thermal conductivity or thermal capacity of the fuel gas are determined and a desired value for the mixing ratio is determined from the physical parameters which depends on the fuel gas or on the composition of the fuel gas, and which desired value is used for the regulation of the mixing ratio.

Abstract: A method for determining physical properties of combustion including: flowing a gas a critical nozzle and past a microthermal sensor wherein the mass flow of the gas through the critical nozzle is the same as the mass flow through the microthermal sensor; measuring the pressure drop in a reservoir of gas flowing to the nozzle; determining a first gas property factor based on the measured pressure drop; determining a second gas property factor based on a flow signal generated by the microthermal sensor; determining a thermal conductivity of the gas using the microthermal sensor; and determining a physical property of the combustion based on a correlation of the first and/or second gas property factors and the thermal conductivity.

Abstract: A method for correcting offset drift effects of a thermal measurement device (10) which comprises at least one temperature sensor (15a, 15b) arranged at a defined distance from a heating device (12) for a fluid to be measured, for measuring at least one measurement variable describing the temperature and/or temperature profile during operation of the heating device (12), in which a reference measured value (35) is measured at a reference time in a first measurement of the measurement variable with the heating device (12) turned off, in which a drift measured value (36) is measured at at least one later time in a second measurement of the measurement variable with the heating device (12) turned off, and in which a drift correction is carried out during the measurement by using the heating device (12) on the basis of a difference between the drift measured value (36) and the reference measured value (35).

Abstract: It is disclosed a method and an apparatus of determining the distance (D) between a collimator lens (13) and an object. Low-coherence light is emitted from a light source (1) and directed the low-coherence light through a collimator lens (13) to the object. The reflected light from the collimator lens (13) and the object is directed to a beam splitter (4) and split into two beams. Within the reference arm the frequency of the beam is shifted by an acousto-optical modulator (5) to a certain frequency and within the delay arm the time delay of the beam is scanned by a variable delay line (7). After combining both beams in a beam combiner (8), the presence of a frequency component equal to the frequency shift of the acousto-optical modulator (5) is detected and the distance (D) between the collimator lens (13) and the object is calculated.

Abstract: It is disclosed a method and an apparatus of determining the distance (D) between a collimator lens (13) and an object. Low-coherence light is emitted from a light source (1) and directed the low-coherence light through a collimator lens (13) to the object. The reflected light from the collimator lens (13) and the object is directed to a beam splitter (4) and split into two beams. Within the reference arm the frequency of the beam is shifted by an acousto-optical modulator (5) to a certain frequency and within the delay arm the time delay of the beam is scanned by a variable delay line (7). After combining both beams in a beam combiner (8), the presence of a frequency component equal to the frequency shift of the acousto-optical modulator (5) is detected and the distance (D) between the collimator lens (13) and the object is calculated.