Apparatus for measuring the velocity and/or through-flow of a fluid

A body for a flow meter for measuring the flow velocity and/or the volumetric through-flow of fluids. The flow meter body has a tubular center piece with connecting flanges for connection to a pipeline for fluids. On its exterior, the center piece has at least two substantially flat mounting surfaces ( 18, 20, 22, 24 ), each of which has at least one receptacle ( 32, 34; 38, 40, 42, 44 ) for mounting a probe ( 35 ). To enable the use of linearly emitting ultrasound probes in such flow meters, and to use the flow meter as a substitute for prior art flow meters without significant effort and cost, it is proposed to arrange the mounting surfaces ( 18 and 20; 22 and 24 ) diametrically opposite each other as a mounting surface pair ( 18-20; 22-24 ) so that the probes ( 35 ) in the opposing mounting surfaces ( 18 and 20; 22 and 24 ) define a measuring path ( 36, 46, 48 ). The mounting surfaces ( 18 and 20; 22 and 24 ) are parallel to each other and at an angle to a longitudinal axis ( 26 ) of center piece ( 12 ).