Abstract: The damper for pressure measuring systems is integrated in the body (5) or insert of a valve. Flow passages (6, 7) communicate with a compartment (9) which is sealed by a rubber-elastic diaphragm (10). The side of the diaphragm remote from said compartment (9) defines a second compartment (13) which is connected to atmosphere through a port (14) designed to provide flow resistance.

Abstract: In a pressure meter catheter which carries a pressure sensor in its measuring tip a reference pressure is admitted to effect zero setting in accordance with the invention while the instrument is in situ during a measurement, the reference pressure permitting adjustment of an evaluating unit at a remote location. Preferably, the measuring tip is surrounded in sealing fashion by a balloon which can be inflated through the line in the catheter tube through which atmospheric pressure is applied to the sensor as reference pressure for the measurement. Thus the same pressure is available both at the measuring connection and at the reference connection of the sensor, and the pressure differential measured by the sensor consequently is exactly zero.