US3845545A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making regenerative heat-exchanger seals
Assignee: British Leyland Truck and Bus Div Ltd
•
Filing: 1972-08-14
•
Granted: 1974-11-05
•
Expires: 1992-08-14
Abstract
Abstract A method of manufacturing a counterface hot-side seal for a rotary disc-type matrix of a regenerative heat-exchanger comprises: forming a composite structure, consisting of a counterface element and a heat-resistant support pad, by preforming the counterface element as highly-compacted blocks and chemically treating the surface thereof which is to mate with the support pad, to produce a metallic layer on that surface; brazing the counterface element to the support pad in an inert atmosphere (e.g. argon or nitrogen); and lapping the counterface to achieve the requisite flatness.
Inventors
- 👤 A Surrall
- 👤 P Candlin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:48
CPC Classifications
F; F28; F28D; F28D19/00; F28D19/04; F28D19/047; Y; Y10; Y10S; Y10S277/00; Y10S277/922; Y10S29/00; Y10S29/034; Y10T; Y10T29/00; Y10T29/49; Y10T29/4935; Y10T29/49357
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
142 words
A method of manufacturing a counterface hot-side seal for a rotary disc-type matrix of a regenerative heat-exchanger for use in a gas turbine engine, which method comprises: a. providing a ferritic support member; b. forming a counterface element from a metal oxide in compacted block form; c. reducing a surface of said metal oxide element to its metal; d. heat treating the said surface; e. applying a paste of brazing powder and flux to said surface and to a surface of said ferritic support member; f. bringing said two surfaces together and raising the assembly so formed to a brazing temperature in an inert atmosphere and thereby brazing the counterface element to the support member; and g. lapping a surface of said counterface element opposite to said first mentioned surface to a requisite flatness for it to serve as a counterface seal.
Claim 2
Independent Claim
142 words
A method of manufacturing a counterface hot-side seal for a rotary disc-type matrix of a regenerative heat-exchanger for use in a gas turbine engine, which method comprises: a. providing a ferritic support member; b. forming a counterface element from a metal oxide in compacted block form; c. reducing a surface of said metal oxide element to its metal; d. heat treating the said surface; e. applying a paste of brazing powder and flux to said surface and to a surface of said ferritic support member; f. bringing said two surfaces together and raising the assembly so formed to a brazing temperature in an inert atmosphere and thereby brazing the counterface element to the support member; and g. lapping a surface of said counterface element opposite to said first mentioned surface to a requisite flatness for it to serve as a counterface seal.
Claim 3
Independent Claim
125 words
A method of manufacturing a counterface hot-side seal for a rotary disc-type matrix of a regenerative heat-exchanger for use in a gas turbine engine, which method comprises: a. providing a ferritic support member; b. forming a counterface element from a nickel oxide; c. applying a solution of sodium hypophosphate and formic acid to a surface of the nickel oxide to reduce it; d. heat treating the nickel surface so produced at approximately 200*C; e. applying a paste of brazing powder and flux to said surface and to a surface of said ferritic support member; and f. bringing said two surfaces together and raising the assembly so formed to a brazing temperature in an inert atmosphere and thereby brazing the counterface element to the support member.
Claim 4
Independent Claim
125 words
A method of manufacturing a counterface hot-side seal for a rotary disc-type matrix of a regenerative heat-exchanger for use in a gas turbine engine, which method comprises: a. providing a ferritic support member; b. forming a counterface element from a nickel oxide; c. applying a solution of sodium hypophosphate and formic acid to a surface of the nickel oxide to reduce it; d. heat treating the nickel surface so produced at approximately 200*C; e. applying a paste of brazing powder and flux to said surface and to a surface of said ferritic support member; and f. bringing said two surfaces together and raising the assembly so formed to a brazing temperature in an inert atmosphere and thereby brazing the counterface element to the support member.
Claim 5
Dependent Claim
23 words
A method as claimed in claim 2 in which nickel oxide is sintered into a highly compacted block to form said counterface element.
Claim 6
Independent Claim
119 words
A method of manufacturing a counterface hot-side seal for a rotary disc-type matrix of a regenerative heat-exchanger for use in a gas turbine engine, which method comprises: a. providing a ferritic support member; b. forming a counterface element from nickel oxide; c. applying a brazing filler metal and a reactive flux to a surface of said support member and to a surface of said nickel oxide support member, said reactive flux containing sodium fluoride and nickel phosphate in an amount equal to approximately 50 percent by weight of the mixture of the brazing filler metal and the flux; and d. bringing said two surfaces together and raising the assembly so formed to a brazing temperature in an inert atmosphere.
Claim 7
Independent Claim
119 words
A method of manufacturing a counterface hot-side seal for a rotary disc-type matrix of a regenerative heat-exchanger for use in a gas turbine engine, which method comprises: a. providing a ferritic support member; b. forming a counterface element from nickel oxide; c. applying a brazing filler metal and a reactive flux to a surface of said support member and to a surface of said nickel oxide support member, said reactive flux containing sodium fluoride and nickel phosphate in an amount equal to approximately 50 percent by weight of the mixture of the brazing filler metal and the flux; and d. bringing said two surfaces together and raising the assembly so formed to a brazing temperature in an inert atmosphere.
Claim 8
Dependent Claim
35 words
A method as claimed in claim 2 in which a surface of said counterface element opposite to said first mentioned surface is then lapped to a flatness enabling it to serve as a counterface seal.
References Cited (Backward Citations)
US2945295A
Cited
US2957239A
Cited
US3271852A
Cited
US3391447A
Cited
US3394451A
Cited
US3667110A
Cited
US3730538A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |