US4273671A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluorescent detection of flaws
Assignee: United States, UNITED STATES AIR FORCE THE, Secretary of
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Filing: 1979-09-18
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Granted: 1981-06-16
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Expires: 1999-09-18
Abstract
Abstract In a method for detecting flaws in the surface of a workpiece, initially microcapsules containing a fluorescent dye are deposited on the surface. After removal of excess microcapsules from the surface in order to reduce background fluorescence, the surface is visually inspected under ultraviolet light. The method overcomes many of the disadvantages of conventional inspection procedures, e.g., by eliminating use of emulsifiers and by materially shortening processing time.
Inventors
- 👤 Sidney Allinikov
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:56
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/91
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
72 words
A product for use in the non-destructive testing of a workpiece to detect cracks or flaws in the surface thereof which consists essentially of a multiplicity of dry, non porous, spherical, thin walled, compressible plastic microcapsules each having encapsulated therein a fluorescent dye detectible by ultraviolet light, and each of said microcapsules having a diameter ranging from 1 to 150 microns together with a wall thickness of about 0.5 to 1.0 microns.
Claim 2
Dependent Claim
72 words
A product for use in the non-destructive testing of a workpiece to detect cracks or flaws in the surface thereof which consists essentially of a multiplicity of dry, non porous, spherical, thin walled, compressible plastic microcapsules each having encapsulated therein a fluorescent dye detectible by ultraviolet light, and each of said microcapsules having a diameter ranging from 1 to 150 microns together with a wall thickness of about 0.5 to 1.0 microns.
Claim 3
Dependent Claim
20 words
The product according to claim 1 in which the microcapsules have a diameter ranging from about 1 to 20 microns.
Claim 4
Dependent Claim
72 words
A product for use in the non-destructive testing of a workpiece to detect flaws or cracks in the surface thereof which consists essentially of a multiplicity of dry, non-porous, spherical, thin-walled, compressible microcapsules, each capsule having a urea-formaldehyde polymeric wall structure encapsulating a fluroescent dye penetrant detectable by ultraviolet light, said each microcapsule having a diameter of about 2 to 5 microns and a wall thickness of about 0.5 to 1.0 microns.
Claim 5
Dependent Claim
72 words
A product for use in the non-destructive testing of a workpiece to detect flaws or cracks in the surface thereof which consists essentially of a multiplicity of dry, non-porous, spherical, thin-walled, compressible microcapsules, each capsule having a urea-formaldehyde polymeric wall structure encapsulating a fluroescent dye penetrant detectable by ultraviolet light, said each microcapsule having a diameter of about 2 to 5 microns and a wall thickness of about 0.5 to 1.0 microns.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-06-15 | 1984-12-15 | 1985-06-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-15 | 1988-12-15 | 1989-06-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-15 | 1992-12-15 | 1993-06-16 | $7700.00 | Window Closed / Lapsed |