Apparatus for detecting changes of length in a medium employing different fiber length

摘要

Apparatus for detecting changes of a medium along a measuring path in the medium, comprising several lightwave conductors arranged on a carrier, conveniently in a sleeve. Reflective ends of the light wave conductors are fixed at different distances along the measuring path. Type, extent, and location of longitudinal changes in the medium to be checked can be detected at any time by optical length measuring of the individual lightwave conductors by means of an optical rangefinder.