Abstract: The ultrasonic sensor comprises an ultrasonic transmitter (11) and an ultrasonic receiver (12) between which an accommodating device (13) for a hose (14) is arranged. The hose is flattened between stamps (21, 22) thus being pressed against rigid concave forming areas (15, 16) where the hose bears in a gap-free manner upon the housing wall (17). The sound velocity in the housing (10) is approximately as large as in the material of the hose (14). In the liquid contained in the hose the sound velocity is considerably smaller. Parallel sound waves are refracted at the interface between hose material and liquid such that the sound waves converge. By concentrating the sound energy into the hose and onto the ultrasonic receiver (12) a high-energy received signal is generated. When air bubbles exist in the liquid, the received signal is attenuated.

Abstract: A medical pump device having a hose pump and a replaceable pump hose and provided with a reading means that reads a code mounted on the pump hose. The code corresponds to the deviation of the delivery volume of the individual hose from the set delivery volume. In dependence on the coding signals, the control signals for the pump drive are corrected so that defined delivery rates are obtained even with in wide hose tolerances.

Abstract: A pressure sensor for determining the pressure of a medium in an elastic hose section. A pressure member acts on a unilaterally fixed bar carrying an influencing member at its free end. This influencing member is a core of a coil arrangement, the position of the core changing the frequencies of the oscillator coils. Numerous pressure values are received at regular intervals and, subsequently, a representative pressure value is obtained by averaging.