Liquid jet removal of plasma sprayed and sintered coatings

- Waterjet Systems, Inc.

Gas turbine engine coatings must often be removed during engine maintenance and repair. The techniques utilized to accomplish this task, machining, chemical stripping, machining followed by chemical stripping, or grit blasting, frequently result in component damage or destruction. Liquid jet erosion can be utilized to remove seals, coatings, or portions thereof without damaging the engine hardware.

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Claims

2. A method as in claim 1 wherein the top coat is selected from the group of plasma sprayed, flame sprayed, and sintered coatings.

3. A method as in claim 1 wherein the top coat is an abradable.Iadd.coating.Iaddend..

4. A method as in claim 1 wherein the top coat is a thermal barrier.Iadd.coating.Iaddend..

5. A method as in claim 1 wherein the top coat is an abrasive.Iadd.coating.Iaddend..

7. A method as in claim 1 wherein the liquid pressure is from about 20,000 psi to about 60,000 psi.

8. A method as in claim 1 using a nozzle as the means for directing the liquid flow.

9. A method as in claim 1 wherein the liquid is selected from the group of liquids consisting of all liquid which does not degrade the bond coat, and has a viscosity between about 0.25 centipoise and about 5.00 centipoise at 25.degree. C. and 1 atm.

10. A method as in claim 1 wherein the liquid is selected from the group consisting of water based liquids.

11. A method as in claim 1 wherein the liquid is essentially water.

14. A method as in claim 13, wherein said top coat and said bond coat are removed simultaneously..Iaddend..Iadd.15. A method as in claim 13, wherein said liquid jet pressure is between about 20,000 psi and about 60,000 psi..Iaddend..Iadd.16. A method for removing a protective coating applied to a substrate which comprises: directing a liquid jet at a pressure above approximately 20,000 psi at the protective coating such that the liquid jet strikes the protective coating thereby removing the protective coating from the substrate whereby the substrate may be reused..Iaddend..Iadd.17. A method as in claim 16, wherein the protective coating is a thermal barrier coating..Iaddend..Iadd.18. A method as in claim 16, wherein the protective coating is an abrasive coating..Iaddend..Iadd.19. A method as in claim 16, wherein the protective coating is an abradable seal..Iaddend..Iadd.20. A method as in claim 16, wherein the protective coating is a hard facing..Iaddend..Iadd.21. A method as in claim 16, wherein the liquid jet pressure is between about 20,000 psi and about 60,000 psi..Iaddend..Iadd.22. A method as in claim 16, wherein the protective coating was applied by a pre-sintering and brazing or a partial

sintering and brazing process..Iaddend..Iadd.23. A method as in claim 16, wherein the protective coating was applied by a partial sintering and brazing process..Iaddend.

Referenced Cited
U.S. Patent Documents
2653116 September 1953 Whitcomb et al.
3413136 November 1968 Emanuelson et al.
3460296 August 1969 Dittmar et al.
4055705 October 25, 1977 Stecura et al.
4285108 August 25, 1981 Arrigoni
4339282 July 13, 1982 Lada et al.
4425185 January 10, 1984 Fishter et al.
4508577 April 2, 1985 Conn et al.
4552594 November 12, 1985 Van Voskuilen et al.
4590026 May 20, 1986 Goto
4607792 August 26, 1986 Young, III
4726104 February 23, 1988 Foster et al.
4859249 August 22, 1989 Valentini
Foreign Patent Documents
0145988 June 1985 EPX
0400758 December 1990 EPX
2630667 November 1989 FRX
8907917 October 1989 DEX
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2042399 January 1979 GBX
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Other references
  • Flow Systems, Application Profile: Coke Oven Door Cleaning, Sep. 1988, (2 pgs), Flow Systems, Inc. Flow Systems, Application Profile: Monument Restoration, Jul. 1988, (2 pgs), Flow Systems, Inc. Smirnov N. S, Prostakov M. E., Process of Cleaning the Surfaces of Steel, Publishing House Metallurgy, 1965, pp. 34 & 36. New Zealand Patent No. 176547 dated Feb. 1977 claims 1-10 and FIGS. 1 and 2 only. New Zealand Patent No. 173992 dated Mar. 1976 claims 1-20 and FIGS. 1-3 only.
Patent History
Patent number: RE35611
Type: Grant
Filed: Nov 16, 1995
Date of Patent: Sep 23, 1997
Assignee: Waterjet Systems, Inc. (Huntsville, AL)
Inventors: Charles C. McComas (Palm City, FL), John W. Appleby, Jr. (Palm Beach Gardens, FL), Gerard A. Sileo (Jupiter, FL), Herbert R. Barringer (Midwest City, OK), Michael J. Patry (Oklahoma City, OK)
Primary Examiner: Jill Warden
Assistant Examiner: Saeed Chaudhry
Application Number: 8/558,342