Method and apparatus for the separation of media

摘要

A plurality of scanning regions (22) are disposed about the anticipated region of a phase boundary (32) of two media. The change in position of the phase boundary (32) is detected by a scanning means (18) with which each scanning region (22) is scanned and a signal is generated for each of the scanning regions (22). The first media is more radiation-permeable than the second media. A beam path is generated by the scanning means and is detected and evaluated by a discriminator circuit as a logic one. The second media is less radiation-permeable than the first media. The absence of a beam path corresponding to scanning regions in the second media is evaluated by the discriminator circuit as a logic zero. The number of signals per measuring cycle is compared against the actual number of scanning regions (22) to locate and control the position of the phase boundary (32).