The Venturi Tube as a Liquefied-Gas Flow Measuring Device

Abstract

The invention relates to a measuring device for checking positioning machines for geometric errors between two rotational joints (2), comprising bearing ball elements (10, 20), which are mechanically connected to each other by means of a telescopic connecting element (30), and an apparatus (40) in order to measure the optical length of the spacing of the bearing ball elements (10, 20) from each other by means of at least one reflector apparatus (12, 22) and a measurement beam (50), wherein the at least one reflector apparatus (12, 22) is arranged in the bearing ball element (10, 20) in such a way that the reference point for the optical length measurement corresponds to the pivot point (11, 21) of the rotational joint (2).