skip to main content
DOE Patents title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Eddy current probe and method for flaw detection in metals

Abstract

A flaw detecting system is shown which includes a probe having a pair of ferrite cores with in-line gaps in close proximity to each other. An insulating, non-magnetic, non-conducting holder fills the gaps and supports the ferrite cores in a manner such that the cores form a generally V-shape. Each core is provided with an excitation winding and a detection winding. The excitation windings are connected in series or parallel with an rf port for connection thereof to a radio frequency source. The detection windings, which are differentially wound, are connected in series circuit to a detector port for connection to a voltage measuring instrument. The ferrite cores at the in-line gaps directly engage the metal surface of a test piece, and the probe is scanned along the test piece. In the presence of a flaw in the metal surface the detection winding voltages are unbalanced, and the unbalance is detected by the voltage measuring instrument. The insulating holder is provided with a profile which conforms to that of a prominent feature of the test piece to facilitate movement of the probe along the feature, typically an edge or a corner.

Inventors:
 [1]
  1. (Sunnyvale, CA)
Issue Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA; Iowa State University, Ames, IA (US)
OSTI Identifier:
866293
Patent Number(s):
4675605
Application Number:
06/698,369
Assignee:
SRI International (Menlo Park, CA) AMES
DOE Contract Number:  
W-7405-ENG-82
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
eddy; current; probe; method; flaw; detection; metals; detecting; shown; pair; ferrite; cores; in-line; gaps; close; proximity; insulating; non-magnetic; non-conducting; holder; fills; supports; manner; form; v-shape; core; provided; excitation; winding; windings; connected; series; parallel; rf; connection; radio; frequency; source; differentially; wound; circuit; detector; voltage; measuring; instrument; directly; engage; metal; surface; piece; scanned; presence; voltages; unbalanced; unbalance; detected; profile; conforms; prominent; feature; facilitate; movement; typically; edge; corner; measuring instrument; metal surface; eddy current; close proximity; radio frequency; voltage measuring; flaw detection; frequency source; current probe; ferrite core; series circuit; facilitate movement; /324/

Citation Formats

Watjen, John P. Eddy current probe and method for flaw detection in metals. United States: N. p., 1987. Web.
Watjen, John P. Eddy current probe and method for flaw detection in metals. United States.
Watjen, John P. Tue . "Eddy current probe and method for flaw detection in metals". United States. https://www.osti.gov/servlets/purl/866293.
@article{osti_866293,
title = {Eddy current probe and method for flaw detection in metals},
author = {Watjen, John P.},
abstractNote = {A flaw detecting system is shown which includes a probe having a pair of ferrite cores with in-line gaps in close proximity to each other. An insulating, non-magnetic, non-conducting holder fills the gaps and supports the ferrite cores in a manner such that the cores form a generally V-shape. Each core is provided with an excitation winding and a detection winding. The excitation windings are connected in series or parallel with an rf port for connection thereof to a radio frequency source. The detection windings, which are differentially wound, are connected in series circuit to a detector port for connection to a voltage measuring instrument. The ferrite cores at the in-line gaps directly engage the metal surface of a test piece, and the probe is scanned along the test piece. In the presence of a flaw in the metal surface the detection winding voltages are unbalanced, and the unbalance is detected by the voltage measuring instrument. The insulating holder is provided with a profile which conforms to that of a prominent feature of the test piece to facilitate movement of the probe along the feature, typically an edge or a corner.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1987},
month = {6}
}

Patent:

Save / Share: