| 摘要 |
1275977 Resistance heating elements G J C (DEVELOPMENT) Ltd 3 Aug 1970 [6 Aug 1969] 39458/69 Headings F4W and W45D A heating element comprises two coaxial tubes 8, 9 transparent to infrared radiation and two heating wires 10, 11, one wire 10 extending within the inner tube 8 and the other wire 11 extending between the tubes 8, 9. The tubes are preferably made of quartz and the wires are helically coiled. The ends of the wires 10, 11 and tubes 8, 9 are retained in recesses in axially split end caps 12. The recesses are lined with glass wool for shock protection. The heating element is mounted at the focal point of a parabolic reflector 5 to which a grill is clipped. Each end cap 12 has flat side faces 18 which are received in a slot 19 in a support plate 4 which prevents rotation. Slots 20 on either side of slot 19 receive T-shaped lugs 21 of a reflector bearing plate 22. The reflector 5 has endplates 25 provided with tubular sleeves 27 which fit telescopically over tubular sleeves 24 provided on bearing plates 22. A coil spring 28 is provided between each end-plate 25 and bearing plate 22. At each end of the heating element plastics end caps are provided. One end cap contains a cordoperated switch which is connected by pull-off terminals to tags 16 which are secured to the respective wires 10, 11. The other end cap contains a single tag connected to both heating wires and by a pull-off terminal to the switch. The switch enables either or both heating wires to be energized. A pull cord is provided for rotating the reflector 5. |
