A device for ascertaining a property of a fluid, having: an electric conductor assembly which is designed to be at least partly brought into contact with the fluid and which is designed as a voltage divider with two elements, wherein the first element is a first conductor which, at least in a current-conducting state, has a resistance value that differs from that of the second element; a measuring bridge with two voltage dividers connected in parallel, one of said voltage dividers being formed by the electric conductor assembly; an actuation unit for applying an AC voltage to the measuring bridge; a voltage detection unit for detecting a bridge voltage; and an analysis unit which is configured to ascertain a thermal conductivity as the property of the fluid by analyzing the bridge voltage using the 3-omega method.

A system for determining one or more properties of one or more gases. The system comprises sensors configured to measure thermal conductivity and exothermic responses of a sample at multiple temperatures. Sensor responses to exposure to a gas sample at two or more temperatures are compensated and analyzed by a subsystem. The subsystem is configured to determine a thermal conductivity of the gas sample at each of the two or more temperatures and determine at least one component of the gas sample based at least in part on the thermal conductivity value of the sample at each of the two or more temperatures. Related systems and methods of determining one or more properties of a sample are also disclosed.

A system for determining one or more properties of one or more gases. The system comprises sensors configured to measure thermal conductivity and exothermic responses of a sample at multiple temperatures. Sensor responses to exposure to a gas sample at two or more temperatures are compensated and analyzed by a subsystem. The subsystem is configured to determine a thermal conductivity of the gas sample at each of the two or more temperatures and determine at least one component of the gas sample based at least in part on the thermal conductivity value of the sample at each of the two or more temperatures. Related systems and methods of determining one or more properties of a sample are also disclosed.

A method for determining at least one gas parameter, of a flowing gas, by means of a flow meter, comprising a measurement section having a heating element and at least three temperature sensors, over which the gas is fed, at least one first temperature sensor being arranged upstream of the heating element, at least one second temperature sensor being arranged in the region of the heating element, and at least one third temperature sensor being arranged downstream of the heating element, wherein a calculation unit determines the at least one gas parameter as a function of the temperature measurement values at the first, second and third temperature sensors, and/or at least two separate gas parameters as a function of the temperature measurement values of individual different temperature sensors and/or the combinations of temperature measurement values of different temperature sensors.

A method for determining at least one gas parameter, of a flowing gas, by means of a flow meter, comprising a measurement section having a heating element and at least three temperature sensors, over which the gas is fed, at least one first temperature sensor being arranged upstream of the heating element, at least one second temperature sensor being arranged in the region of the heating element, and at least one third temperature sensor being arranged downstream of the heating element, wherein a calculation unit determines the at least one gas parameter as a function of the temperature measurement values at the first, second and third temperature sensors, and/or at least two separate gas parameters as a function of the temperature measurement values of individual different temperature sensors and/or the combinations of temperature measurement values of different temperature sensors.

A heat flux sensor comprising at least one support, where at least one membrane is suspended relative to the support by at least four nanowires, where the membrane is made from at least one current-conducting material, and where the nanowires are made from a current-conducting material, with two nanowires connected to a current source to polarize the membrane between two terminals and a heater for heating the membrane, and where two nanowires are connected to a voltmeter to form measure the voltage at the terminals of the membrane.

A heat flux sensor comprising at least one support, where at least one membrane is suspended relative to the support by at least four nanowires, where the membrane is made from at least one current-conducting material, and where the nanowires are made from a current-conducting material, with two nanowires connected to a current source to polarize the membrane between two terminals and a heater for heating the membrane, and where two nanowires are connected to a voltmeter to form measure the voltage at the terminals of the membrane.

Provided is a thermal conductivity detector including a detection channel through which a gas to be measured flows as a fluid, a heat conducting part that includes at least a filament provided at a position in the detection channel at which the filament is in direct contact with the fluid flowing through the detection channel, the filament being folded at least once in a direction substantially parallel to a flow direction of the fluid flowing through the detection channel, and that conducts heat via the fluid flowing through the detection channel, and a detection circuit that detects an electric signal in accordance with a change in current or voltage of the filament. The filament is folded by being holed on a folding pin provided substantially perpendicular to the flow direction in the detection channel, and the folding pin has a position shift prevention structure for preventing a fold of the filament hooked on the folding pin from shifting in a longitudinal direction of the folding pin.

The described sensor allows determination of the concentration of a gas in a two-component mixture at variable pressure by measuring the diffusivity and the thermal conductivity. The sensor is provided to alternately heat the membrane of a thermally conductive cell and allow it to cool such that the temperature T.sub.M of the membrane passes from a first stable value to a second stable value and vice versa via a transient mode. The cell produces a signal representative of the temperature T.sub.M of the membrane and the sensor extracts from the signal a first and a second parameter that respectively relate to said first stable value and said transient mode of the signal. A value of the concentration of said gas and of the pressure of said two-mixture is calculated from these two parameters.

The described sensor allows determination of the concentration of a gas in a two-component mixture at variable pressure by measuring the diffusivity and the thermal conductivity. The sensor is provided to alternately heat the membrane of a thermally conductive cell and allow it to cool such that the temperature T.sub.M of the membrane passes from a first stable value to a second stable value and vice versa via a transient mode. The cell produces a signal representative of the temperature T.sub.M of the membrane and the sensor extracts from the signal a first and a second parameter that respectively relate to said first stable value and said transient mode of the signal. A value of the concentration of said gas and of the pressure of said two-mixture is calculated from these two parameters.