Abstract: In ultrasound flow rate meters, an acoustical short circuit between ultrasonic transducers is a special problem. Such a short circuit results in an ultrasonic signal being propagated through a wall of a measuring tube from a sending to a receiving transducer and not being influenced by a medium in the measuring tube. Sealing off a gas path around the ultrasonic transducers is also problematic. In order to solve the problem, the ultrasonic transducers are sheathed with an elastomer molded body. From 25% to 60% of an outer surface of the ultrasonic transducer, which is constructed as a cup-type transducer, is lined with the elastomer molded body, beginning at a cup edge thereof. Contact of the holder with the ultrasonic transducer is minimal and occurs only in an acoustically quiet zone.

Abstract: A space saving funnel inlet and funnel outlet is provided proceeding from the pipe connections of bellows gas meters with 90.degree. flow deflection for ultrasonic gas flowmeters with a low pressure loss, high flow linearity and gas-independent calibration. This is achieved using a funnel inlet and funnel outlet for the 90.degree. deflection of a gas flowing into and out of a measurement channel of a measurement pipe for an ultrasonic gas flowmeter, respectively. The walls forming the width of the measurement channel are spaced at a distance s from one another and are curved in a particular way in the region of the funnel inlet and funnel outlet (for example, horns curved away at right angles).