Capacitive measurement head for thickness of thermoplastic foil - has bar-shaped inner electrode enclosed by flattened ring outer electrode, both with low coefficient of thermal expansion

摘要

The measurement head capacitively contains a bar-shaped inner electrode (3') enclosed by an outer electrode (7) to form a narrow annular gap. The outer electrode is annular with a profile approximately equal in width to the inner electrode. It can be a flattened ring. The electrodes are of a metal with a low coefficient of thermal expansion and are of approximately equal wt. USE/ADVANTAGE - For blown tubing (for Z). Measurement head is insensitive to temp. variations of foil being measured.