US3774013A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat treating appliance for stress-relieving steel piping and like structures
Assignee: Individual
•
Filing: 1972-11-13
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Granted: 1973-11-20
•
Expires: 1992-11-13
Abstract
Abstract A heat treating appliance wrappable about welded steel pressure piping and like structures for relieving stresses therein and coilable to compact form for storage and transport comprises lengths of a pliable electrical heating cable held in parallel relation by and along an elongate flexible reticular support such as a long sleeve knitted of heat-resistant wire, with means on the ends of electrical resistance wires in the cable lengths for connecting them in parallel with a source of electric current. Each cable length preferably comprises a single solid strand of a Cr-Ni alloy resistance wire sheathed within several braided insulating layers of amorphous silica fiber, with an armor layer of heat resistant Ni-Cr alloy wire braided over the insulating sheath. By the use of a suitable number of the heating appliances wrapped about the stressed regions, steel pressure piping ranging from 2 inches to 48 inches in O.D. and from 1/4 inch to 5 1/2 inches in wall thickness can be readily subjected to normalizing treatment at an appropriate temperature between about 1,100* and 1,800* and thus relieved of stresses in regions near welded joints thereof.
Inventors
- 👤 H Keep
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:45
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/40; H05B3/54; H05B3/58
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
178 words
A heating appliance adapted to be wrapped in contiguous coils about a steel pipe or like structure and heated by electrical resistance to bring the structure to a normalizing temperature in the range of about 1,100 to 1,800* F., comprising an elongate flexible reticular support resistant to all temperatures of said range, said support being flexible in all directions transverse to its longitudinal axis, a plurality of lengths of a pliable electrical heating cable disposed along and held in substantially parallel relation by said support, each of said cable lengths comprising an electrical heating element composed of an alloy suited for being heated by electrical resistance to a temperature above said range and, on said element, an electrically insulating sheath resistant to its heating temperature, said support being a knitted sleeve of heat resistant wire having said lengths of cable disposed therewithin and laterally spaced apart between opposite knitted wall sections thereof, and means for connecting the ends of the respective heating elements of said cable lengths in parallel in a circuit containing a source of electric current.
Claim 2
Dependent Claim
178 words
A heating appliance adapted to be wrapped in contiguous coils about a steel pipe or like structure and heated by electrical resistance to bring the structure to a normalizing temperature in the range of about 1,100 to 1,800* F., comprising an elongate flexible reticular support resistant to all temperatures of said range, said support being flexible in all directions transverse to its longitudinal axis, a plurality of lengths of a pliable electrical heating cable disposed along and held in substantially parallel relation by said support, each of said cable lengths comprising an electrical heating element composed of an alloy suited for being heated by electrical resistance to a temperature above said range and, on said element, an electrically insulating sheath resistant to its heating temperature, said support being a knitted sleeve of heat resistant wire having said lengths of cable disposed therewithin and laterally spaced apart between opposite knitted wall sections thereof, and means for connecting the ends of the respective heating elements of said cable lengths in parallel in a circuit containing a source of electric current.
Claim 3
Dependent Claim
35 words
A heating appliance according to claim 1, said wall sections being joined together along respective longitudinal regions thereof between said cable lengths so that said cable lengths are held laterally spaced apart within said sleeve.
Claim 4
Dependent Claim
24 words
A heating appliance according to claim 2, said wall sections being so joined together by welds formed therebetween at intervals along said regions thereof.
Claim 5
Dependent Claim
48 words
A heating appliance according to claim 1, said heating element being a single solid strand of electrical resistance wire, said sheath comprising several superimposed layers of amorphous silica fiber braided upon said element, and said cable having a shielding layer of heat-and oxidation-resistant wire braided upon said sheath.
Claim 6
Dependent Claim
62 words
A heating appliance according to claim 1, the wire of said sleeve being a heat-resistant nickel-chromium alloy wire, said heating element being a single strand of a chromium-nickel electrical resistance wire, said sheath comprising several superimposed layers of amorphous silica fiber braideD upon said resistance wire, and said cable having a shielding layer of heat-resistant nickel-chromium alloy wire braided upon said sheath.
Claim 7
Dependent Claim
53 words
A pliable electrical heating cable for an appliance according to claim 1, comprising a heating element composed of a single solid strand of electrical resistance wire, an electrically insulating sheath comprising several superimposed layers of amorphous silica fiber braided upon said element, and a shielding layer of heat-resistant wire braided upon said sheath.
Claim 8
Dependent Claim
30 words
A heating cable according to claim 6, said strand being composed of a chromium-nickel electrical resistance alloy and the wire of said shielding layer being a heat-resistant nickel-chromium alloy wire.
Claim 9
Dependent Claim
247 words
A heating appliance adapted to be wrapped in contiguous coils about a steel pipe or like structure and heated by electrical resistance to bring the structure to a normalizing temperature in the range of about 1,100* to 1,800* F., comprising an elongate flexible reticular support resistant to all temperatures of said range, said support being flexible in all directions transverse to its longitudinal axis, a plurality of lengths of a pliable electrical heating cable disposed along and held in substantially parallel relation by said support, each of said cable lengths comprising an electrical heating element composed of an alloy suited for being heated by electrical resistance to a temperature above said range and, on said element, an electrically insulating sheath resistant to its heating temperature, said support being a knitted sleeve of heat resistant wire having said lengths of cable disposed therewithin and laterally spaced apart between opposite knitted wall sections thereof, and means for connecting the ends of the respective heating elements of said cable lengths in parallel in a circuit containing a source of electric current, said wall sections being joined together by welds formed between them at intervals along respective longitudinal regions thereof between said cable lengths, said heating element of each said cable length being a single solid strand of electrical resistance wire, said sheath thereof comprising several superimposed layers of amorphous silica fiber braided upon said resistance wire, and a shielding layer of heat- and oxidation- resistant wire braided upon said sheath.
Claim 10
Dependent Claim
247 words
A heating appliance adapted to be wrapped in contiguous coils about a steel pipe or like structure and heated by electrical resistance to bring the structure to a normalizing temperature in the range of about 1,100* to 1,800* F., comprising an elongate flexible reticular support resistant to all temperatures of said range, said support being flexible in all directions transverse to its longitudinal axis, a plurality of lengths of a pliable electrical heating cable disposed along and held in substantially parallel relation by said support, each of said cable lengths comprising an electrical heating element composed of an alloy suited for being heated by electrical resistance to a temperature above said range and, on said element, an electrically insulating sheath resistant to its heating temperature, said support being a knitted sleeve of heat resistant wire having said lengths of cable disposed therewithin and laterally spaced apart between opposite knitted wall sections thereof, and means for connecting the ends of the respective heating elements of said cable lengths in parallel in a circuit containing a source of electric current, said wall sections being joined together by welds formed between them at intervals along respective longitudinal regions thereof between said cable lengths, said heating element of each said cable length being a single solid strand of electrical resistance wire, said sheath thereof comprising several superimposed layers of amorphous silica fiber braided upon said resistance wire, and a shielding layer of heat- and oxidation- resistant wire braided upon said sheath.
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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) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |