Source: http://www.google.com/patents/US5374122?dq=7,496,943
Timestamp: 2014-10-20 04:28:06
Document Index: 749716116

Matched Legal Cases: ['art. 2', 'art.\n7', 'art. 8', 'art.\n10', 'art. 11', 'art 30', 'art 30']

Patent US5374122 - Method for quantifying porosity of parts of simple and complex geometries - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA method and apparatus for inspecting nonmetallic parts, including composite parts for, e.g. aircraft engines by quantifying their porosity, wherein a laser beam is directed to one side of the part to heat a portion thereof, with a delay being noted for the applied heat to transmit through said part...http://www.google.com/patents/US5374122?utm_source=gb-gplus-sharePatent US5374122 - Method for quantifying porosity of parts of simple and complex geometriesAdvanced Patent SearchPublication numberUS5374122 APublication typeGrantApplication numberUS 08/010,953Publication dateDec 20, 1994Filing dateJan 29, 1993Priority dateJan 29, 1993Fee statusPaidPublication number010953, 08010953, US 5374122 A, US 5374122A, US-A-5374122, US5374122 A, US5374122AInventorsJohn W. Devitt, Eric A. AndersonOriginal AssigneeThe United States Of America As Represented By The Secretary Of The Air ForceExport CitationBiBTeX, EndNote, RefManPatent Citations (13), Non-Patent Citations (2), Referenced by (7), Classifications (9), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetMethod for quantifying porosity of parts of simple and complex geometriesUS 5374122 AAbstract A method and apparatus for inspecting nonmetallic parts, including composite parts for, e.g. aircraft engines by quantifying their porosity, wherein a laser beam is directed to one side of the part to heat a portion thereof, with a delay being noted for the applied heat to transmit through said part to the opposite side thereof. An infrared radiometer (IR) is mounted to view such opposite side and to read (after such delay) the heat transmitted therethrough in the form of voltage (increase) readings. Such IR readings are taken at points across the part being inspected and the readings are then compared to a known data base of temperature change against vol. % porosity or the resulting calibrated porosity curve, to quantify the % porosity at various points on the sample. The inventive method can read or quantify porosity parts of simple geometry as well as of complex geometry, including engine housing flanges of small radii of curvature.
What is claimed is: 1. A method for quantifying porosity of a non-metallic part having a first side and a second side substantially opposite said first side comprising:a) applying heat to said first side by a gas jet or laser beam which relatively moves as a heating spot across a portion of said first side, b) viewing said part on said second side with an infrared radiometer which tracks the moving heating spot on said second side after a sufficient delay to permit heat to pass through said part to said second side, to detect the heat transmitted through said part as a change in infrared levels obtained and c) comparing said change in infrared levels obtained to a known data base of said levels from calibrated porosity samples or a curve of said data base, to quantify the porosity of a plurality of points on said part. 2. The method of claim 1 wherein the heat applied to said part is by a laser beam and said part is a composite part.
7. An apparatus for quantifying porosity of a non-metallic part having a first side and a second side substantially opposite said first side comprising:a) means for directing a gas jet or laser beam at said first side as a relatively moving heating spot thereon, to transmit heat through said part to said second side, b) an infrared radiometer (IR) directed at said second side, which tracks said moving heating spot on said second side after a sufficient delay to permit heat to pass through said part to said second side, to detect the heat transmitted through said part as a change in infrared levels obtained and c) means for comparing said change in infrared levels obtained to a known data base of said levels from calibrated porosity samples or a curve of said data base, to quantify the porosity of a plurality of points on said part. 8. The apparatus of claim 7 wherein said IR is directed at said second side at an angle θ with the incoming laser beam and means for rotating said part between said laser beam and said IR across said angle θ, to allow for said delay in detecting the heat transmitted through said part.
10. A method for quantifying porosity of a non-metallic part having a first side and a second side substantially opposite said first side comprising:a) applying heat to said first side by a laser beam which relatively moves as a laser spot across a portion of said first side, b) viewing said part on said second side with an infrared radiometer which tracks the moving laser spot on said second side after a sufficient delay to permit heat to pass through said part to said second side, to detect the heat transmitted through said part as a change in infrared levels obtained and c) comparing said change in infrared levels obtained to a known data base of said levels from calibrated porosity samples or a curve of said data base, to quantify the porosity of a plurality of points on said part. 11. The method of claim 10 wherein said part is of complex geometry, said part being relatively moved across said laser beam, said infrared radiometer being directed at said second side at an angle θ offset from said laser beam so as to allow for said delay in detecting the heat transmitted through said part.
SUMMARY OF THE INVENTION Broadly the present invention provides a method for quantifying porosity in non metallic parts comprising,
DESCRIPTION OF PREFERRED EMBODIMENTS Referring now in more detail to the drawings, laser emitter 20 directs its beam 22 through a divergent lens 24 to pivotable mirror 26, which directs the expanding laser beam 28 to part 30 of simple geometry, as shown in FIG. 1. The mirror 26 pivots so as to move the laser spot 32 across the part 30, in a path 34, in the direction of arrow 36, as shown in FIG. 1. The sample 30 is monitored on its reverse side, by infrared radiometer(IR) 40 which pivots in delayed tracking of the spot 32 as it moves across the sample 30, i.e. lags behind such spot to allow time for heat from the laser beam 28 to penetrate the sample 30 to the reverse side thereof, for heat penetration data, as indicated in FIG. 1. Such delayed tracking of the heat spot 32 in the sample 30 by the IR 40, yields more accurate heat penetration and thus porosity data than concurrent tracking of such spot would do.
EXAMPLE I Several calibrated porosity composite parts were obtained for this example. The samples were of a composite material of woven graphite mesh imbeded in a thermoset plastic, sold commercially in the U.S. as "PMR-15". The samples were sized about 2 in. by 3 in. by 1/4 in. The porosity ranged from 2.7 to 9.5 vol. %, the region of interest. An Nd:YAG laser at 1.06 μm was used to heat the part under test from one direction. A nine second burst at 12 W was used in this example. The part was observed on its opposite side, with an inframetrics 210 IR camera operating in the 8-12 μm band. The data were recorded after a six second time lag after the heating pulse was stopped. The results were as follows.
TABLE I______________________________________   START      FINISH           POROSITYSAMPLE  V (volts)  V        &#916;VIR                               vol. %______________________________________6293-6  31         202      171     2.76294-0  18         156      138     3.256294-1  19         123      104     3.506293-2  23         160      137     3.856294-5  21         140      119     3.3-4.46294-6  29         129      105     3.8-9.56293-0  29         166      137     5.336294-3  24         106       82     5.686294-2  27         113       86     5.7-6.66293-3  29         146      117     6.3-7.16293-4  24         114       90     9.0-9.56293-5  27         101       74     9.1-10.2______________________________________
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3939698 *May 23, 1974Feb 24, 1976General Dynamics CorporationMethod and apparatus for measuring porosity using a surface-temperature porosimeterUS4236403 *Jun 14, 1978Dec 2, 1980Thermonetics CorporationMeans and techniques useful in establishing R values in insulationUS4453398 *Dec 15, 1982Jun 12, 1984Iowa State University Research Foundation, Inc.For deriving measurement concerning porosity of a materialUS4623263 *Nov 1, 1984Nov 18, 1986Commissariat A L'energie AtomiqueApparatus for the thermal measurement of the texture of a porous bodyUS4640627 *Aug 26, 1983Feb 3, 1987The Perkin-Elmer CorporationApparatus for monitoring a plasma torchUS4817020 *Jun 22, 1987Mar 28, 1989General Electric CompanyCooling rate determination apparatus for laser material processingUS4818102 *Dec 22, 1986Apr 4, 1989United Technologies CorporationActive optical pyrometerUS4840496 *Feb 23, 1988Jun 20, 1989The United States Of America As Represented By The Administrator Of The National Aeronautics And Space AdministrationNoncontact temperature pattern measuring deviceUS4928254 *Apr 28, 1988May 22, 1990Knudsen Arne KLaser flash thermal conductivity apparatus and methodUS5001657 *Dec 6, 1989Mar 19, 1991Minolta Camera Kabushiki KaishaRadiation thermometerUS5044767 *Dec 6, 1989Sep 3, 1991Thermetrol AbDevice for measuring thermal properties of a test substance-the transient plane source (TPS) methodUS5159569 *Nov 19, 1990Oct 27, 1992Board Of Supervisors Of Louisiana State University And Agricultural And Mechanical CollegeFormation evaluation from thermal propertiesSU1659786A1 * Title not available* Cited by examinerNon-Patent CitationsReference1Somerton, W., "Some Thermal Characteristics of Porous Rocks," Petroleum Transactions, AIME, pp. 375-378 (1958).2 *Somerton, W., Some Thermal Characteristics of Porous Rocks, Petroleum Transactions, AIME, pp. 375 378 (1958).* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS5803606 *Dec 7, 1994Sep 8, 1998Phototherm Dr. Petry GmbhSurface photothermic testing deviceUS6000844 *Mar 4, 1997Dec 14, 1999The United States Of America As Represented By The Administrator Of The National Aeronautics And Space AdministrationMethod and apparatus for the portable identification of material thickness and defects using spatially controlled heat applicationUS7018094 *Oct 13, 2000Mar 28, 2006Airbus Uk LimitedMaterial analysisUS7044636 *Apr 29, 2003May 16, 2006National Institute Of Advanced Industrial Science And TechnologyMethod of measuring fast time response using fast pulse and system of the sameUS8642164 *Sep 15, 2011Feb 4, 2014United Technologies CorporationComposite substrates with predetermined porositiesUS20130071603 *Sep 15, 2011Mar 21, 2013United Technologies CorporationComposite substrates with predetermined porositiesEP2492671A1 *Feb 28, 2011Aug 29, 2012Siemens AktiengesellschaftMethod of detecting wrinkles in a fiber reinforced laminated structure and auxiliary device for performing thermal scans of a fiber reinforced laminated structure* Cited by examinerClassifications U.S. Classification374/45, 73/38, 374/153International ClassificationG01N25/72, G01N15/08Cooperative ClassificationG01N15/088, G01N25/72European ClassificationG01N15/08M, G01N25/72Legal EventsDateCodeEventDescriptionMar 27, 2006FPAYFee paymentYear of fee payment: 12Jun 19, 2002FPAYFee paymentYear of fee payment: 8Apr 6, 1998FPAYFee paymentYear of fee payment: 4Apr 29, 1993ASAssignmentOwner name: UNITED STATES OF AMERICA, THE, AS REPRESENTED BY TFree format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:DEVITT, JOHN W.;ANDERSON, ERIC A. (GENERAL ELECTRIC COMPANY);REEL/FRAME:006505/0391;SIGNING DATES FROM 19930121 TO 19930122RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google