Wall thickness detector
AssigneeEmhart Industries, Inc.
InventorsPaul F. Scott, Donald C. Button, Charles B. Reeves, Edward D. Howerter
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Abstract
A capacitive probe for a wall thickness detector comprises a plurality of flexible capacitive elements and an elastomeric body supporting the flexible capacitive elements and biasing them against a dielectric body at an inspection site. A first metallic shield is supported between the elastomeric body and the capacitive elements and a second metallic shield is supported on the other side of the capacitive elements in close proximity thereto and has a window to expose the capacitive elements to the dielectric member.
Claims5
A capacitive circuit laminate for a capacitive probe in a wall thickness detector, said capacitive circuit laminate comprising:
- a middle layer including three elongated, equally spaced flexible metallic capacitive elements,
- means for applying a non-zero voltage waveform to the central of said capacitive elements, and
- means for shorting said other two outer capacitance elements to ground so that a capacitance field will be generated which is confined to a region approximately bounded by parallel planes through said outer capacitance elements and normal to said middle layer,
- a rear layer including a thin metallic shield for shielding the rear surface of said middle layer, and
- a front layer including a thin metallic shield for shielding the front surface of said middle layer and having a window for exposing a selected length of said capacitive elements of said middle layer whereby an electromagnetic field may emanate from said central one of said capacitive elements, pass outwardly through said window into the vicinity of a dielectric member, and return back through said window to said outer capacitive elements, and
- means for driving the thin metallic shields of said rear and front layers with said non-zero voltage waveform.
Dependencies are inferred from the claim text.