Abstract: A relative pressure measuring instrument has a reference pressure feed that offers a high measure of safety and is easy to produce.

Abstract: The invention relates to an apparatus for determining and/or monitoring the viscosity of a medium in a container, having a unit which can oscillate, having a drive/reception unit and having a control/evaluation unit, in which case the unit which can oscillate is arranged at a defined measurement position within the container and/or in which case a unit which can oscillate is fitted such that it is immersed as far as a defined immersion depth in the medium, and in which case the drive/reception unit excites the unit which can oscillate to oscillate and/or in which case the drive/reception unit receives the oscillations from the unit which can oscillate. The control/evaluation unit uses the frequency/phase curve (&phgr;=g(f)) of the unit which can oscillate to determine the viscosity (&eegr;) of the medium.

Abstract: A differential pressure sensor, for determining the differential pressure between two measuring points, comprises a pressure vessel which is filled with a transfer fluid; a measuring cell which is arranged in the pressure vessel and is surrounded by the transfer fluid, with two half-cells; a diaphragm-like deforming body which separates the two half-cells from each other in a pressuretight manner; two pressure supply lines, which respectively feed the pressure from one of the two measuring points outside the pressure vessel to one of the two half-cells; and at least one pressure accumulator, the pressure of which acts on the transfer fluid in the vessel. Elastic or compressible bodies with a linear or degressive characteristic are suitable as the pressure accumulator. The pressure accumulator compensates for changes in volume of the transfer fluid on account of temperature fluctuations.

Abstract: An apparatus for determining a physical process variable of a medium (2) which can be used in conjunction with various sensor types, the sensors having in common that they determine a process variable by means of a delay-time method. The apparatus has a sensor (4), a sensor-specific application unit (5) and an evaluation unit (6), which is essentially independent of the sensor type used, the sensor (4) being assigned a transmitting/receiving unit (7), the transmitting unit (7a) transmitting measuring signals in the direction of the medium (2) and the receiving unit (7b) receiving the measuring signals influenced by the interaction with the medium (2), and the application unit (5) being designed in such a way that it provides measurement data, independently of the type of sensor (4) used, from which the evaluation unit (6) determines the physical process variable using a delay-time method by means of a uniform evaluation algorithm.