Abstract: A method determines a measured quantity relating to the flow of a fluid through a measuring tube, in two propagation directions, and a receive signal is captured. A transit time difference is determined depending on the position of the main maximum of a cross-correlation of the receive signals. Whereupon the measured quantity is determined depending on the transit time difference, and the transmitting ultrasonic transducer is controlled in each case with an excitation signal. The excitation signal has a fixed carrier frequency. The excitation signal has a phase shift and/or an envelope with a plurality of temporally spaced maxima, and/or, if a trigger condition is fulfilled, the fulfilment of which depends on the height of the main maximum and/or of at least one secondary maximum of the cross-correlation. The determination of the measured quantity is modified compared with a normal operating mode and/or a message is output.

Abstract: A measuring device, in particular a flow meter, has a measurement tube for receiving or conveying a fluid, first and second oscillation transducers on a side wall of the measurement tube, and a control device. An operating method has the control device drive the first oscillation transducer chronologically in succession for respective mode-selective excitation of a first and a second oscillation mode of a wave conducted in the side wall of the measurement tube. The second oscillation transducer is driven similarly for a second measurement direction. The excited waves are conducted directly in the side wall or indirectly through the fluid and recorded in the other oscillation transducer, resulting in measurement data for each measurement direction and oscillation mode. Result information relates to a property of the fluid or a state of the measuring device determined from the measurement data for both measurement directions and both respective oscillation modes.

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 operating a measuring device determining a fluid quantity relating to fluid or fluid flow uses a measuring tube receiving the fluid or conducting the flow and oscillation transducers spaced along the tube. A first flight time is recorded, then an ultrasound signal excited by a first transducer, after travel on a propagation path including only components of the measuring device to a second transducer, is recorded at a second transducer. A second flight time is recorded, then an ultrasound signal excited by the second transducer, after travel on the propagation path to the first transducer, is recorded at the first transducer. Then fulfillment of a report condition depending on a difference between flight times is checked. Upon fulfillment, a report is output to a user or a report message is sent to an external device or a correction parameter for determining the fluid quantity is adapted.

Abstract: A measurement device for ascertaining a pressure in a measurement volume which receives a fluid or through which fluid flows. The measurement volume is bounded at least sectionally by a side wall and a vibration transducer is arranged on the side wall. The vibration transducer is actuable by a control device of the measurement device to excite a wave that is guided through the side wall. The guided wave is able to be guided through the side wall along a propagation path back to the vibration transducer or to at least one further vibration transducer and it is captured there by the control device in order to ascertain measurement data. The pressure in the measurement volume is then ascertained by the control device in dependence on the measurement data.

Abstract: A measuring device for determining a fluid variable relating to a fluid or fluid flow includes a control device, a measuring tube receiving the fluid or fluid flow, and oscillation transducers spaced apart on the measuring tube. At least one oscillation transducer is drivable by the control device to excite a wave conducted through at least one side wall of the measuring tube, the conducted wave exciting compression oscillations of the fluid conducted through the fluid to the other oscillation transducer and recorded there by the control device to determine measurement data. The fluid variable can be determined by the control device as a function of the measurement data. At least one further side wall of the measuring tube has at least one recess extending in a flow direction and increasing a flow cross section of the measuring tube. A method for determining a fluid variable is also provided.

Abstract: A measuring device determines a fluid variable via a control device. A measuring tube serves to guide the fluid, and a first vibration transducer is arranged at the measuring tube. The first vibration transducer has a supporting device and two vibration elements spaced apart from one another. A spring element is clamped between a side face of the vibration elements averted from the measuring tube, which presses the respective vibration element against the measuring tube. The control device drives the vibration elements such that they excite a guided wave in a side wall of the measuring tube guided directly in the side wall or indirectly via the fluid to a second vibration transducer arranged at the measuring tube or back to the first vibration transducer, to be detected there by the control device resulting in measurement data. The control device determines the fluid variable depending on the measurement data.

Abstract: A measuring device determines a fluid variable with a control device, a measuring tube and a first vibration transducer arranged at the measuring tube. The first vibration transducer contains a vibration element. The vibration element has a vibration body, a first electrode on the measuring tube side and a second electrode averted from the measuring tube. The first electrode extends over a first end face of the vibration body. The second electrode extends to a second end face that lies opposite the first end face. A respective conductive contact element contacts the first electrode at a first end face and the second electrode at a second end face electrically and mechanically such that the vibration element is supported by the contact elements. A voltage between the first and second electrodes can be varied through the vibration element to excite a guided wave in a side wall of the measuring tube.

Abstract: A measuring device, in particular a flow meter, has a measurement tube for receiving or conveying a fluid, first and second oscillation transducers on a side wall of the measurement tube, and a control device. An operating method has the control device drive the first oscillation transducer chronologically in succession for respective mode-selective excitation of a first and a second oscillation mode of a wave conducted in the side wall of the measurement tube. The second oscillation transducer is driven similarly for a second measurement direction. The excited waves are conducted directly in the side wall or indirectly through the fluid and recorded in the other oscillation transducer, resulting in measurement data for each measurement direction and oscillation mode. Result information relates to a property of the fluid or a state of the measuring device determined from the measurement data for both measurement directions and both respective oscillation modes.

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 operating a measuring device determining a fluid quantity relating to fluid or fluid flow uses a measuring tube receiving the fluid or conducting the flow and oscillation transducers spaced along the tube. A first flight time is recorded, then an ultrasound signal excited by a first transducer, after travel on a propagation path including only components of the measuring device to a second transducer, is recorded at a second transducer. A second flight time is recorded, then an ultrasound signal excited by the second transducer, after travel on the propagation path to the first transducer, is recorded at the first transducer. Then fulfillment of a report condition depending on a difference between flight times is checked. Upon fulfillment, a report is output to a user or a report message is sent to an external device or a correction parameter for determining the fluid quantity is adapted.

Abstract: A measurement device for ascertaining a pressure in a measurement volume which receives a fluid or through which fluid flows. The measurement volume is bounded at least sectionally by a side wall and a vibration transducer is arranged on the side wall. The vibration transducer is actuable by a control device of the measurement device to excite a wave that is guided through the side wall. The guided wave is able to be guided through the side wall along a propagation path back to the vibration transducer or to at least one further vibration transducer and it is captured there by the control device in order to ascertain measurement data. The pressure in the measurement volume is then ascertained by the control device in dependence on the measurement data.

Abstract: A measuring device for determining a fluid variable relating to a fluid or fluid flow includes a control device, a measuring tube receiving the fluid or fluid flow, and oscillation transducers spaced apart on the measuring tube. At least one oscillation transducer is drivable by the control device to excite a wave conducted through at least one side wall of the measuring tube, the conducted wave exciting compression oscillations of the fluid conducted through the fluid to the other oscillation transducer and recorded there by the control device to determine measurement data. The fluid variable can be determined by the control device as a function of the measurement data. At least one further side wall of the measuring tube has at least one recess extending in a flow direction and increasing a flow cross section of the measuring tube. A method for determining a fluid variable is also provided.