(12) United States Patent ao) Patent No.: us 6,636,031 Bi
Kenmochi et al. (45) Date of Patent: Oct. 21,2003
(54) METHOD AND DEVICE FOR DETECTING PINHOLES IN ORGANIC FILM ON CONCRETE SURFACE
(75) Inventors: Fukio Kenmochi, Kawasaki (JP);
Takao Tsurudome, Kawasaki (JP);
Masaaki Houki, Osaka (JP); Noboru
Yamazaki, Osaka (JP)
(73) Assignees: Sanko Electronic Laboratory Co.,
Ltd., Kanagawa (JP); Shinko Electric & Instrumentation Co., Ltd, Osaka (JP)
( * ) Notice: Subject to any disclaimer, the term ol this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/679,899
(22) Filed: Oct. 5, 2000
(51) Int. CI.7 G01R 1/04; G01R 27/08;
(52) U.S. CI 324/158.1; 324/557; 324/691
(58) Field of Search 324/557, 558,
324/559, 691, 693, 707, 710, 718, 719, 514, 512, 71.1; 340/605; 73/40, 40.5 R,
(56) References Cited
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JP 2001324407 A * 11/2001 G01N/27/92
* cited by examiner
Primary Examiner—Kamand Cuneo Assistant Examiner—Jermele Hollington (74) Attorney, Agent, or Firm—TraskBritt
A technique for detecting whether or not a pinhole is present in an organic film on a concrete surface, by detecting the conductivity of the concrete in advance. In the bottom portion of a measuring means body having a high-frequency oscillator accommodated therein, there are disposed electrodes which are insulated from each other through an insulating plate. Two electrodes are provided in parallel and are placed in contact with the surface of the lining film coating the surface of the concrete body. Thus, the electrodes are held in contact with the surface of the lining film, and a high-frequency signal is fed from the high-frequency oscillator to between the electrodes. Then, by detecting the specific dielectric, constant of the concrete body or the base body indirectly from the surface layer of the organic film without breaking the organic film formed on the surface to expose the surface of the concrete body, the conductivity of the concrete can be examined from the correlation between the specific dielectric constant and the water content, as investigated in advance, and the correlation between the water content and the electric resistance.
4 Claims, 5 Drawing Sheets