Process and device for the nondestructive measurement of material accumulations or coating thicknesses on dielectric materials, in particular plastic

US4520308A · kind A · utility

Assignee

• Elektro Physik Hans Nix & Dr. Erich Steingroever · DE

Inventors

• Thomas Rohde · Minneapolis, US
• Friedhelm Caspers · Bochum, DE

Key dates

• Filing date: Sep 7, 1982
• Grant date: May 28, 1985
• Expiry date: Sep 7, 2002

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B15/02
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A process and apparatus for the non-destructive measurement of the thickness of sheets or hollow bodies made of dielectric materials, such as plactis, makes use of a microwave frequency signal which is fed to an elongated microwave strip line which is placed either close to, or in contact with, the material to be measured, whereby the change in the propagation time of the signal represents the thickness, or the filling factor of the measured material. In the case of hollow bodies the strength of the signal is insufficient to be affected by the wall of the body remote from the conductor, and an advantage of the system is that it can be used to measure plastic materials while in a plastic state while in the process of extrusion.