Heating assembly using tungsten-halogen lamps

• US 4,864,104 A
• Filed: 01/12/1988
• Issued: 09/05/1989
• Est. Priority Date: 12/24/1982
• Status: Expired due to Term

• Current Assignee: Thorn EMI Patents Limited
• Original Assignee: Thorn EMI Patents Limited
• Inventors: Crossley, Peter W., Fellerman, Bernard F., Goodchild, Graham H.
• Primary Examiner(s): Walberg, Teresa J.
• Application Number:
  US07/143,063
• Time in Patent Office: 602 Days
• Field of Search: 219/464, 219/458, 219/459, 219/460, 219/461, 219/465, 219/466, 219/448, 219/449, 219/354
• US Class Current: 219/462.1
• CPC Class Codes: H05B 2213/04 Heating plates with overheat protection means
• CPC Class Codes: H05B 2213/07 Heating plates with temperature control means
• CPC Class Codes: H05B 3/744 Lamps as heat source, i.e. heating elements with protective gas envelope, e.g. halogen lamps
• CPC Class Codes: H05B 3/746 Protection, e.g. overheat cutoff, hot plate indicator

Abstract

A heating assembly including at least one infra-red emissive tungsten halogen lamp supported beneath a glass ceramic cooktop which allows useful quantities of the infra-red radiation, as emitted by the lamp (or lamps) and directly incident on the undersurface of the cooktop, to emerge from the assembly and above non-metallic, thermally insulating material contained as a layer in the base of a shallow tray. The layer contains, or supports at its surface, material which efficiently reflects the infra-red radiation emitted from the lamp (or lamps) substantially unchanged in spectral content so that useful quantities of the radiation so reflected and then incident on the undersurface of the cooktop emerge from the assembly to supplement the directly incident radiation.

Claims

1. A heating assembly comprising:

at least one tungsten halogen lamp capable when energized of generating infra-red radiation having a predetermined wavelength spectrum, a cooktop of glass ceramic material usefully transparent to infra-red radiation in part at least of said spectrum, means supporting said at least one lamp beneath said cooktop, thermally insulative and infra-red reflective means disposed beneath said at least one lamp and said cooktop and capable of inhibiting transmission of heat away from said cooktop and also of reflecting towards said cooktop without significant spectral change infra-red radiation generated by said at least one lamp and initially directed away from said cooktop, said thermally insulative and infra-red reflective means consisting at least of a non-metallic material, the cooktop, said at least one lamp and said thermally insulative and infra-red reflective means being juxtaposed and in closely proximate relationship with one another, whereby said assembly is of shallow construction and exhibits relatively rapid thermal response to energization and deenergization of said at least one lamp, the assembly further including limiting means responsive to the temperature of said cooktop to de-energize said at least one lamp when said temperature reaches a predetermined maximum value.

2. An assembly according to claim 1, wherein said non-metallic material comprises a microporous material.

3. An assembly according to claim 2, wherein said non-metallic material supports metallic oxide material reflective of infra-red radiation generated by said at least one lamp.

4. An assembly according to claim 1, wherein said non-metallic material supports metallic oxide material reflective of infra-red radiation generated by said at least one lamp.

5. An assembly according to claim 1, including a tray member containing and supporting said non-metallic material.

6. An assembly according to claim 1, including an optical filter for obstructing undesirable visible light.

7. A cooking hob incorporating at least one heating assembly as claimed in claim 1.