Abstract: A measuring device for measuring an amount of a rinsing additive to be metered into a rinsing, washing or disinfecting process in a rinsing machine includes a measuring segment for conveying the rinsing additive. The measuring segment has a defined length and a defined diameter, and includes a first cylindrical widening at an upstream end therof. An ultrasound sensor is associated with the measuring segment for performing a measurement of at least one of a running time, an amplitude and a phase as a function of a flow rate of the rinsing additive so as to enable a determination of at least one of a type and an amount of the additive flowing through the measuring segment. A cap including a cylindrical indentation is received in the cylindrical widening so as to form an annular chamber.