Patent US1124140A successfully refreshed from Google Patents.
Patent US3684853A successfully refreshed from Google Patents.
US3684853A
Expired / Lapsed
US
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Induction surface heating unit system
Assignee: General Electric Co
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Filing: 1971-10-18
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Granted: 1972-08-15
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Expires: 1991-10-18
Abstract
Abstract An induction surface heating unit system for use in cooking foods having an induction heating coil driven with an ultrasonic frequency wave to pass an alternating magnetic flux through a cooking utensil that is supported on a plate above the heating coil. The utensil is of special laminated construction having a center core of high thermal conductivity, non-magnetic material and a thin outer skin bonded to the core and being of magnetic and high electrical resistivity material. The induction heating coil functions as the primary winding of a transformer and the outer skin of the utensil functions as a short-circuited singleturn secondary winding such that current flowing through the utensil causes a heating effect to take place in the utensil itself. The impedance of the utensil is matched to the power conversion circuit of the heating coil for best overall efficiency of coupling the power to the load. The center core serves as a heat spreader to distribute the heat uniformly throughout the utensil.
Inventors
- 👤 Stanley B Welch
- 👤 Raymond L Dills
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:59
CPC Classifications
A; A47; A47J; A47J36/00; A47J36/24; A47J36/2483; A47J36/02; H; H05; H05B; H05B6/00; H05B6/02; H05B6/10; H05B6/12; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12736; Y10T428/1275; Y10T428/12757; Y10T428/12771; Y10T428/12861; Y10T428/12903; Y10T428/12917; Y10T428/12924; Y10T428/12951; Y10T428/12972; Y10T428/12979
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
126 words
An induction surface heating unit system comprising an induction coil with an ultrasonic frequency wave, said coil being mounted beneath a cooking utensil support plate, and a composite plate utensil positioned on the support plate and substantially centered over the said coil, said induction heating coil functioning in a manner as the primary winding of a transformer, said utensil functioning in the manner as a single-turn secondary winding, said composite plate material of the utensil having a center core selected from the group of high thermal conductivity metals and alloys such as copper, silver and aluminum, and an outer skin bonded to the core and selected from the group of magnetic and high electrical resistivity materials such as iron, porcelain enameled steel and martensitic stainless steel.
Claim 2
Dependent Claim
126 words
An induction surface heating unit system comprising an induction coil with an ultrasonic frequency wave, said coil being mounted beneath a cooking utensil support plate, and a composite plate utensil positioned on the support plate and substantially centered over the said coil, said induction heating coil functioning in a manner as the primary winding of a transformer, said utensil functioning in the manner as a single-turn secondary winding, said composite plate material of the utensil having a center core selected from the group of high thermal conductivity metals and alloys such as copper, silver and aluminum, and an outer skin bonded to the core and selected from the group of magnetic and high electrical resistivity materials such as iron, porcelain enameled steel and martensitic stainless steel.
Claim 3
Dependent Claim
33 words
An induction surface heating unit system as recited in claim 1 wherein the said center core material is of a thickness greater than the combined thickness of outer skin for better thermal conductivity.
Claim 4
Dependent Claim
170 words
An induction surface heating unit system comprising an induction heating coil, said coil being mounted beneath a cooking utensil support plate, said induction coil functioning in the manner as the primary winding of a transformer; the invention comprising a utensil of a composite plate material which functions in the manner as a shorted single-turn secondary winding such that an alternating magnetic field produced by the induction coil is magnetically coupled across an air gap with the utensil material, said composite plate material having a center core of high thermal conductivity such as copper and a thin outer skin of high resistance magnetic material such as porcelain enameled steel bonded over the core, so that the heating of the utensil takes place in the outer skin of the composite material in the area substantially directly above the underlying heating coil and this heat is transferred by large area conduction to the center core which in turn spreads the heat laterally to obtain generally uniform temperatures within the bottom of the utensil.
Claim 5
Dependent Claim
170 words
An induction surface heating unit system comprising an induction heating coil, said coil being mounted beneath a cooking utensil support plate, said induction coil functioning in the manner as the primary winding of a transformer; the invention comprising a utensil of a composite plate material which functions in the manner as a shorted single-turn secondary winding such that an alternating magnetic field produced by the induction coil is magnetically coupled across an air gap with the utensil material, said composite plate material having a center core of high thermal conductivity such as copper and a thin outer skin of high resistance magnetic material such as porcelain enameled steel bonded over the core, so that the heating of the utensil takes place in the outer skin of the composite material in the area substantially directly above the underlying heating coil and this heat is transferred by large area conduction to the center core which in turn spreads the heat laterally to obtain generally uniform temperatures within the bottom of the utensil.
Claim 6
Dependent Claim
34 words
An induction surface heating unit system as recited in claim 3 wherein the said center core of the composite plate material is of a thickness greater than the combined thickness of the outer skin.
Claim 7
Dependent Claim
135 words
An induction surface heating unit system comprising an induction heating coil means adapted to be driven by an ultrasonic output frequency wave, said coil means being covered by a cooking utensil support plate of non-metallic material; the invention comprising a cooking utensil of laminated materials of magnetic material and high electrical resistivity and high thermal conductivity, said laminated utensil material comprising a center core of high thermal conductivity metals and alloys selected from the group comprising copper, silver and aluminum, the core being sealed within an outer skin of ferromagnetic material that is electrically conductive to form a short circuited turn of a transformer of which the primary winding is represented by the said induction heating coil, said ferromagnetic material being selected from the group comprising iron, porcelain enameled steel, martensitic stainless steel and nickel.
Claim 8
Dependent Claim
135 words
An induction surface heating unit system comprising an induction heating coil means adapted to be driven by an ultrasonic output frequency wave, said coil means being covered by a cooking utensil support plate of non-metallic material; the invention comprising a cooking utensil of laminated materials of magnetic material and high electrical resistivity and high thermal conductivity, said laminated utensil material comprising a center core of high thermal conductivity metals and alloys selected from the group comprising copper, silver and aluminum, the core being sealed within an outer skin of ferromagnetic material that is electrically conductive to form a short circuited turn of a transformer of which the primary winding is represented by the said induction heating coil, said ferromagnetic material being selected from the group comprising iron, porcelain enameled steel, martensitic stainless steel and nickel.
Claim 9
Dependent Claim
117 words
An electric cooking apparatus comprising an induction heating system having an induction heating coil means that generates an alternating magnetic field, said coil means being covered by a cooking utensil support plate of non-conducting material, and a cooking utensil of laminated materials having a center core of high thermal conductivity metals and alloys selected from the group comprising copper, silver and aluminum, the core being sealed within a thin outer skin of ferromagnetic material that is electrically conductive to form a short-circuited turn of a transformer of which the primary winding is represented by the said induction heating coil, said ferromagnetic material being selecTed from the group comprising iron, porcelain enameled steel, martensitic stainless steel and nickel.
Claim 10
Dependent Claim
117 words
An electric cooking apparatus comprising an induction heating system having an induction heating coil means that generates an alternating magnetic field, said coil means being covered by a cooking utensil support plate of non-conducting material, and a cooking utensil of laminated materials having a center core of high thermal conductivity metals and alloys selected from the group comprising copper, silver and aluminum, the core being sealed within a thin outer skin of ferromagnetic material that is electrically conductive to form a short-circuited turn of a transformer of which the primary winding is represented by the said induction heating coil, said ferromagnetic material being selecTed from the group comprising iron, porcelain enameled steel, martensitic stainless steel and nickel.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |