Abstract: The invention relates to a method for determining the flow or the flow rate of a medium in an electrically conductive object, in particular a pipe (1) or a pipeline, through which a medium flows. At least one ultrasonic wave (16) is produced by means of a transmitting transducer (11) in the object and is injected into the medium as a longitudinal wave (8) on an inner side of the object, and an ultrasonic signal, coming at least partially from the longitudinal wave (8), is received by the receiving transducer (12), at a spatial distance from the injection point and is used to evaluate the flow or the flow rate. Said transmitting transducer (11) produces, preferably in the absence of an acoustic coupling with the surface of the object, a first variable magnetic field in an area close to the surface of the object, in particular metallic, and a first ultrasonic wave is produced in said area by means of the interaction of said variable magnetic field with a static or quasi-static magnetic field.

Abstract: Acoustic flow rate meter for the noninvasive determination of the flow or the flow rate in electrically conductive objects through which media flow, in particular pipes or pipelines, having an excitation transducer for generating at least one ultrasonic wave in the object, which is coupled into the medium as a longitudinal wave on an inner side of the object oriented toward the medium, and having a receiving transducer for the detection of an ultrasonic signal in the object, wherein the ultrasonic signal at least partially results due to the longitudinal wave, wherein the excitation transducer is implemented as a high-frequency induction coil, while omitting an acoustic coupling of the excitation transducer with the surface of the object, to generate a varying magnetic field in a surface-proximal region of the object, which is metallic in particular, and the ultrasonic wave is generated by interaction of the varying magnetic field with a static or quasi-static magnetic field in this region.

Abstract: The invention relates to a method for determining the flow or the flow rate of a medium in an electrically conductive object, in particular a pipe (1) or a pipeline, through which a medium flows. At least one ultrasonic wave (16) is produced by means of a transmitting transducer (11) in the object and is injected into the medium as a longitudinal wave (8) on an inner side of the object, and an ultrasonic signal, coming at least partially from the longitudinal wave (8), is received by the receiving transducer (12), at a spatial distance from the injection point and is used to evaluate the flow or the flow rate. Said transmitting transducer (11) produces, preferably in the absence of an acoustic coupling with the surface of the object, a first variable magnetic field in an area close to the surface of the object, in particular metallic, and a first ultrasonic wave is produced in said area by means of the interaction of said variable magnetic field with a static or quasi-static magnetic field.

Abstract: Acoustic flow rate meter for the noninvasive determination of the flow or the flow rate in electrically conductive objects through which media flow, in particular pipes or pipelines, having an excitation transducer for generating at least one ultrasonic wave in the object, which is coupled into the medium as a longitudinal wave on an inner side of the object oriented toward the medium, and having a receiving transducer for the detection of an ultrasonic signal in the object, wherein the ultrasonic signal at least partially results due to the longitudinal wave, wherein the excitation transducer is implemented as a high-frequency induction coil, while omitting an acoustic coupling of the excitation transducer with the surface of the object, to generate a varying magnetic field in a surface-proximal region of the object, which is metallic in particular, and the ultrasonic wave is generated by interaction of the varying magnetic field with a static or quasi-static magnetic field in this region.