Patent US3973918A successfully refreshed from Google Patents.
US3973918A
Expired / Lapsed
US
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Method of making a gas-fired furnace
Assignee: JPMorgan Chase Bank NA
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Filing: 1975-12-05
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Granted: 1976-08-10
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Expires: 1995-12-05
Abstract
Abstract This specification discloses a method of making a high efficiency gas-fired furnace with aluminized steel heat exchangers which are specially prepared for higher heat exchange efficiency by heat treatment of the heat exchanger shells.
Inventors
- 👤 James T. Tidwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:45
CPC Classifications
B; B23; B23P; B23P15/00; B23P15/26; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/923; Y10S428/924; Y10S428/926; Y10T; Y10T29/00; Y10T29/49; Y10T29/4935; Y10T29/49826; Y10T29/49893; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12736; Y10T428/1275; Y10T428/12757; Y10T428/12764
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
155 words
A method of making a high efficiency gas furnace having aluminized steel heat exchangers comprising the steps of: providing a metallic sheet material having a steel substrate, an iron-aluminum alloy intermediate bonding layer overlying said substrate and substantially iron-free aluminum outer layer overlying said intermediate layer; forming from said sheet material a plurality of concavo-convex sheet metal heat exchanger shells; connecting a pair of said heat exchanger shells together to form a hollow body heat exchanger; heating said heat exchanger shells substantially throughout within an oven to a temperature between that necessary to melt said iron-free aluminum outer layer as a lower limit and that required to anneal said steel substrate as a higher limit to improve the heat exchange efficiency of said heat exchanger shells; withdrawing said heat exchanger shells from said oven and cooling said heat exchanger shells substantially to ambient temperature; and installing said hollow body heat exchanger into a furnace housing.
Claim 2
Independent Claim
155 words
A method of making a high efficiency gas furnace having aluminized steel heat exchangers comprising the steps of: providing a metallic sheet material having a steel substrate, an iron-aluminum alloy intermediate bonding layer overlying said substrate and substantially iron-free aluminum outer layer overlying said intermediate layer; forming from said sheet material a plurality of concavo-convex sheet metal heat exchanger shells; connecting a pair of said heat exchanger shells together to form a hollow body heat exchanger; heating said heat exchanger shells substantially throughout within an oven to a temperature between that necessary to melt said iron-free aluminum outer layer as a lower limit and that required to anneal said steel substrate as a higher limit to improve the heat exchange efficiency of said heat exchanger shells; withdrawing said heat exchanger shells from said oven and cooling said heat exchanger shells substantially to ambient temperature; and installing said hollow body heat exchanger into a furnace housing.
Claim 3
Dependent Claim
30 words
The method as defined in claim 1 wherein said heat exchanger shells are heated during said heating step to a temperature within the range of about 1065°F and about 1800°F.
Claim 4
Dependent Claim
34 words
The method as defined in claim 1 wherein said step of heating said heat exchanger shells is performed subsequent to said step of connecting said shells together to form a hollow body heat exchanger.
Claim 5
Dependent Claim
30 words
The method as defined in claim 2 wherein said heat exchanger shells are heated during said heating step to a temperature within the range of about 1400°F and about 1800°F.
Claim 6
Dependent Claim
24 words
The method as defined in claim 2 wherein said heat exchanger shells are heated to a temperature within the range of 1450°F and 1550°F.
Claim 7
Dependent Claim
20 words
The method as defined in claim 2 wherein said heat exchanger shells are heated to a temperature of about 1500°F.
Claim 8
Dependent Claim
33 words
The method as defined in claim 1 wherein said heat exchanger shells are heated for a sufficient duration to transform the outermost surface thereof from a substantially iron-free aluminum to an iron-aluminum alloy.
Claim 9
Dependent Claim
24 words
The method as defined in claim 6 wherein said heat exchanger shells are heated for a duration of between about 1 and 15 minutes.
Claim 10
Dependent Claim
21 words
The method as defined in claim 6 wherein said heat exchanger shells are heated for a duration of about 5 minutes.
Claim 11
Dependent Claim
27 words
The method as defined in claim 6 wherein said heat exchanger shells are heated to a temperature of about 1500°F for a period of about 5 minutes.
Claim 12
Dependent Claim
22 words
The method as defined in claim 6 wherein said heat exchanger shells are heated in a substantially air atmosphere within said oven.
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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) | 1979-08-10 | 1980-02-09 | 1980-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-10 | 1984-02-09 | 1984-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-10 | 1988-02-09 | 1988-08-10 | $7700.00 | Window Closed / Lapsed |