US3581144A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Metal-clad insulated electrical heater
Assignee: General Electric Co
•
Filing: 1969-03-27
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Granted: 1971-05-25
•
Expires: 1989-03-27
Abstract
Abstract A low mass insulated heater that can be bonded with low thermal drop to an object to be heated consists of a planar arrangement of a heater wire which, after being covered with a thin coating of insulation, is coated with material that is sintered or alloyed to form a metallic sheath. The sheath is brazed directly to a member to be heated to form an integrally bonded structure in which the composite materials all have similar thermal expansion characteristics.
Inventors
- 👤 James E Beggs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:49
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/20; H01J1/22; H05; H05B; H05B3/00; H05B3/40; H05B3/42; H05B3/48; H05B3/50; H05B3/68; H05B3/688
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
178 words
An electrical heater comprising coplanar turns of a heater wire, input terminals for said wire, the metal of the wire being selected from the group consisting of molybdenum and tungsten; a coating of insulating material surrounding said wire, said insulating material being selected from a group consisting of alumina, a mixture of boron nitride and alumina, and a mixture of boron nitride and magnesium oxide; a metal overcoating surrounding the insulating material, the metal of said overcoating being selected from the group consisting of molybdenum and tungsten; a layer of metal attached to at least one side of said overcoated wire, the metal of said layer consisting of molybdenum or an alloy of molybdenum and nickel; the proportions of said insulating materials and the materials of said wire, overcoating metal, and metal layer all being selected to have closely matched thermal expansion characteristics over a wide range of temperatures; and a metal object to be heated having a flat surface parallel with and integrally attached to said metal layer, said metal object having similar matching thermal expansion characteristics.
Claim 2
Dependent Claim
178 words
An electrical heater comprising coplanar turns of a heater wire, input terminals for said wire, the metal of the wire being selected from the group consisting of molybdenum and tungsten; a coating of insulating material surrounding said wire, said insulating material being selected from a group consisting of alumina, a mixture of boron nitride and alumina, and a mixture of boron nitride and magnesium oxide; a metal overcoating surrounding the insulating material, the metal of said overcoating being selected from the group consisting of molybdenum and tungsten; a layer of metal attached to at least one side of said overcoated wire, the metal of said layer consisting of molybdenum or an alloy of molybdenum and nickel; the proportions of said insulating materials and the materials of said wire, overcoating metal, and metal layer all being selected to have closely matched thermal expansion characteristics over a wide range of temperatures; and a metal object to be heated having a flat surface parallel with and integrally attached to said metal layer, said metal object having similar matching thermal expansion characteristics.
Claim 3
Dependent Claim
20 words
The electrical heater of claim 1 in which said metal object comprises a cathode disc attached to said metal layer.
Claim 4
Dependent Claim
38 words
The electrical heater of claim 2 in which a layer of metal is attached to both sides of said overcoated grid and a backup disc is attached to the metal layer on the side opposite the cathode disc.
Claim 5
Dependent Claim
31 words
The heater of claim 1 in which the heater wire and overcoating consist of molybdenum, the metal layer is an alloy of molybdenum and nickel, and the insulating material is alumina.
Claim 6
Dependent Claim
32 words
The heater of claim 1 in which the heater wire and overcoating consist of tungsten, the metal layer is an alloy of molybdenum and nickel, and the insulating material is boron nitride.
Claim 7
Dependent Claim
23 words
The heater of claim 1 in which the metal of said object is selected from the group consisting of molybdenum, tungsten and nickel.
Claim 8
Dependent Claim
17 words
The heater of claim 6 in which the metal of the object to be heated is tungsten.
Claim 9
Dependent Claim
17 words
The heater of claim 6 in which the metal of the object to be heated is molybdenum.
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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) | 1974-05-24 | 1974-11-23 | 1975-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-24 | 1978-11-23 | 1979-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-24 | 1982-11-23 | 1983-05-25 | $7700.00 | Window Closed / Lapsed |