Abstract: A measurement device ascertains the thermal conductivity of a fluid. The device has a fluid volume holding the fluid, a controller, and a sensor module disposed in the fluid volume. The sensor module has a supporting body and a plurality of sensor wires that extend freely between in each case two contact positions of the supporting body. One of the sensor wires serves as a heat source and is able to be energized for this purpose by the controller. The controller is set up to capture, via at least two of the sensor wires that serve as temperature sensors and are arranged at different distances from the heat source, temperature measurement values that depend on the temperature at the respective temperature sensor, and to ascertain the thermal conductivity in dependence on the temperature measurement values.

Abstract: A thermal gas sensor for measuring the thermal diffusivity and/or the thermal conductivity of a gas or gas mixture includes a substrate. In the surface of the substrate a trench is formed, as well as at least two conductor structures arranged at a distance from one another on the surface of the substrate. The conductor structures respectively each contain at least two contact sections and a web section connected to the contact sections, the web sections of the conductor structures crossing over the trench at a distance from one another. At least one slot is formed between at least two contact sections of different conductor structures in at least one region of the surface of the substrate.

Abstract: A thermal gas sensor for measuring the thermal diffusivity and/or the thermal conductivity of a gas or gas mixture includes a substrate. In the surface of the substrate a trench is formed, as well as at least two conductor structures arranged at a distance from one another on the surface of the substrate. The conductor structures respectively each contain at least two contact sections and a web section connected to the contact sections, the web sections of the conductor structures crossing over the trench at a distance from one another. At least one slot is formed between at least two contact sections of different conductor structures in at least one region of the surface of the substrate.

Abstract: A measurement device ascertains the thermal conductivity of a fluid. The device has a fluid volume holding the fluid, a controller, and a sensor module disposed in the fluid volume. The sensor module has a supporting body and a plurality of sensor wires that extend freely between in each case two contact positions of the supporting body. One of the sensor wires serves as a heat source and is able to be energized for this purpose by the controller. The controller is set up to capture, via at least two of the sensor wires that serve as temperature sensors and are arranged at different distances from the heat source, temperature measurement values that depend on the temperature at the respective temperature sensor, and to ascertain the thermal conductivity in dependence on the temperature measurement values.

Abstract: A method for determining the volumetric flow rate of a fluid medium through a measuring section in a substantially gas-type-independent manner, includes heating the medium in a pulsed manner by using a heating element, detecting a first point in time at which a temperature maximum occurs at a first temperature sensor, the first temperature sensor being disposed adjacently upstream or downstream of the heating element, detecting a second point in time at which a temperature maximum occurs at a second temperature sensor, the second temperature sensor being disposed downstream of the heating element, the second temperature sensor being further away from the heating element than the first temperature sensor, and ascertaining a time difference between the first and second points in time. The volumetric flow rate is determined in dependence on the time difference. A device for carrying out the method is also provided.