Thorn Emi Plc

Thorn Electrical Industries Limited

Thorn Emi Domestic Appliances Limited

Thorn Emi Appliances Limited

Alex L Halberstadt

John A Letchford

Roger Alan Hume

Peter W Crossley

Stephen J Newton

Geoffrey I Bell

John C Maddocks

Kenneth S Frost

Susan M Crocker

A tungsten halogen lamp producing infra red radiation, for example for cooking or heating, has an envelope of high silica content material sealed at each end by a pinch seal. A gas fill is at a room temperature pressure of 250-750 mm Hg. A portion of the envelope at each end is clear and the rest contains an opacifier which reduces transmission of visible light. A suitable opacifier is red, being produced by the reduction of copper oxide dispersed in the high silica content material. The envelope is produced by butt joining clear end sections and a tube of material containing opacifier.

Tungsten halogen lamp

A microwave oven consists of an oven cavity containing a turntable, a source of microwave energy and a waveguide for directing microwave energy into the oven cavity. Two lamp units accommodate tungsten-halogen lamps for browning food cooked by the microwave energy. To inhibit arcing through the lamps due to exposure to the microwave energy, support coils supporting the filament of each lamp are each formed from an incomplete turn of the coil to inhibit arcing between adjacent regions thereof. Other modifications to the lamps and/or the units may also be provided to protect the lamps from exposure to the microwave energy.

Microwave oven having a source of infra-red radiation

An incandescent lamp, which emits infra-red radiation, comprises a tubular quartz envelope, within which a tungsten filament is supported. To reflect radiation, which is emitted in a downward direction from the filament, back in an upward direction to an item to be heated, a substantially pure aluminum oxide coating is bonded in a substantially permanent manner to the surface of the envelope. The coating extends subtantially along the length of the lamp and around approximately half of the cross-sectional circumference thereof. The coating is applied to the envelope by a spray gun technique, wherein finely divided aluminum powder is blown through an oxygenated flame, which is directed towards an area of the envelope to be coated.

Incandescent lamps

Filter holder

An infra-red lamp consists of a quartz tubular envelope sealed at each end with a respective pinch seal. A tungsten filament supported within the envelope is electrically connected, via a molybdenum foil strip and lead wires within the pinch seal to a connector for connection to a power supply. Each pinch seal is substantially wholly enclosed within a ceramic housing, which is preferably provided with a locating flange, to protect the pinch seal in part from heat emitted by the filament and to assist in location of the lamp in an operating environment.

Quartz infra-red lamps

Heating apparatus includes a tray having a layer of insulative material disposed therewithin, above which a number of infra-red lamps are supported. The ends of each lamp are provided with a pinch seal having an amp tag connector, which is connected to the respective end of a filament within the lamp, sealed therein. Each pinch seal is enclosed within a ceramic housing and the heating apparatus is mounted beneath a layer of glass ceramic. A heat-conductive stud is intimately disposed between the layer and the pinch seal, via an aperture in the housing, so as to provide a good heat-conductive path from the pinch seal to the relatively cool glass ceramic.

Heating apparatus

An improved electric mirror lamp comprising a concave mirror on the focus of which a light source, for example an incandescent filament is fixed, and the lamp also includes locating means by which its position in a lamp holder is determined and support means holding the mirror at a fixed position relative to the locating means. A support mirror is an integral moulded body having portions adapted to position the locating of the mirror. The locating means may be constituted by a locating ring secured to an end cap and the support means may include indentations which engage and retain the end cap. The electric light source or bulb may be replaceable and the mirror may be formed directly on an appropriate concave surface of the support means.

Growing community of inventors

London, United Kingdom

Alex L Halberstadt