Thermal measuring and testing – Leak or flaw detection – With heating or cooling of specimen for test
Patent
1994-12-08
1996-12-10
Gutierrez, Diego F. F.
Thermal measuring and testing
Leak or flaw detection
With heating or cooling of specimen for test
374124, G01N 2572
Patent
active
055824854
ABSTRACT:
An instrument employs a projector which projects a moving pattern of heat onto a test object. An exemplary pattern is formed of bars or lines of infrared radiation separated by unheated areas, or areas of shadow. An infrared camera which is not sensitive to the wavelength of the projected light is used to detect the heat emitted by the test object. The projected bands of thermal radiation heat the surface of the test object. Some of the energy in the form of heat sinks into the structure, while some of the heat energy flows laterally from the heated band to the unheated bands between the projected bands. The lateral flow of heat between bands is resisted by cracks in the surface. This resistance causes heat energy to build up on one side of each crack. The downward flow of heat energy is resisted by less conductive material such as a debonding between layers which traps the heat, causing it to build up laterally. Thus, flaws caused by cracks normal to the surface and delaminations or cracks parallel to the surface may be detected by the same device.
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Gutierrez Diego F. F.
Stress Photonics Inc.
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