Patent Number: 6,297,648

Title: Oscillating cavity paint meter

Abstract: A measuring instrument and method for measuring paint and coating thickness on poorly conductive graphite substrates. The instrument uses a microwave amplifier, a measurement cavity, and an optional reference cavity with supporting electronics to measure the apparent changes in the length of the measurement cavity due to the changes in the paint and coating thickness. The measurement cavity resonates when the measurement cavity is set upon the test surface. The oscillating signal is sent through a) directly to a microwave frequency counter, or b) a reference cavity tuned to give the desired slope detection response to cover the paint and coating thickness range allowed. The filtered response of the reference cavity is converted to a dc level signal proportional to paint thickness. It is presumed that the expert user will have access to a PC allowing instant conversion--via a stepped calibration plate--to paint thickness in mils from electrical data.

Inventors: Lunden; C. David (Federal Way, WA)

Assignee: The Boeing Company

International Classification: G01B 15/02 (20060101); G01R 027/04 ()

Expiration Date: 10/02/2018