Fluid analysis utilizing acoustic waveguides applied angularly to fluid flow

A fluid measuring device for determining at least one characteristic property of a fluid, comprising:

• a measuring tube having a fluid duct through which the fluid can flow and which has a measuring section in which the measuring tube is cylindrical on an inside and at least an area of a curved measuring tube wall is configured as a waveguide for surface acoustic waves which forms an interface to the fluid, and
• at least one transmitter for exciting acoustic waves in the waveguide and at least one receiver for receiving acoustic waves from the waveguide which are arranged in direct contact with an outer surface of the waveguide,
• wherein part of an energy of the acoustic waves excited by the transmitter is coupled into the fluid and propagates at least in sections as a volume wave through the fluid,
• wherein the waveguide has a single or a plurality of elongated waveguide paths which, with respect to a center line thereof, extend at least in sections at an acute angle to a longitudinal extension direction of the measuring tube and in addition with a component in a circumferential direction,
• wherein in the area of the single or the plurality of waveguide paths, the measuring tube wall has a smaller wall thickness than in areas of the measuring tube adjoining the waveguide path (s),
• wherein as seen in the longitudinal extension direction of the measuring tube, the single waveguide path has or the plurality of waveguide paths each have a first end and a second end, a transmitter being provided at at least one first end and a receiver being provided at at least one second end, wherein only the ends of the single or plurality of waveguide paths at which a transmitter or a receiver is arranged, are flattened while a remaining portion of the waveguide path is curved, the flattened ends forming a planar contact surface for the transmitter or the receiver.