Patent GB-372342-A (GB)
Title: Improvements in apparatus for emitting light and heat
IPC: A61N5/08
Filed: 1931-01-29
Abstract: <PICT:0372342/III/1> <PICT:0372342/III/2> Apparatus for producing light, heat and ultra-violet rays, suitable for the treatment of food and other substances, comprises one or more hermetically sealed evacuated tubular receptacles 1 disposed substantially vertically and constructed from glass, fused quartz, silica or other material which transmits such rays, the lower end of each receptacle containing a quantity of mercury 2 and adapted to be heated continuously by external means.  The latter may comprise oil or gas burners, gas-heated incandescent mantles, gas fires, radiators and other electric heaters.  The exteriors of the ends of the receptacles are preferably provided with spaced conducting surfaces for the passage of alternating current through the vaporized mercury, and the receptacles may also contain a minute quantity of neon or other gas. The tubes 1 extend between an upper insulating plate 3, Fig. 1, and a lower trough-like casing 5 which is supported on a rod 7 so that the tubes may be slightly inclined forwardly or rearwardly.  The casing 5 is lined with asbestos 11 and filled with fireclay or other refractory material 12 providing a tunnel 13 for a pipe 14 provided with gas burners 15, vertical apertures 16 for the flames to act directly on the tubes 1, and passages for the escape of combustion products.  The plate 3 supports a metal plate 18 in contact with caps 19 on the ends of the tubes and with securing bolts 6 which are enclosed in insulating sleeves 20, and the lower ends of the tubes are fitted with caps 24 so that alternating current can be passed through the tubes from a supply which may be located within the base 9.  The caps 19, 24 may be replaced by a layer of metal deposited or painted on the ends of the tubes, and the apparatus may be fitted with a reflector 25 and a protecting cover 26.  The gas burners may be replaced by similarly located electric heating resistances, or, as shown in Fig. 4, the bottom of each tube may be surrounded by an electric heating coil 27 wound on cylindrical formers 28, with or without an intermediate layer of fireclay 29.  The following features are described in one or both of the Provisional Specifications.  A vaporizable material other than mercury may be employed and it may be contained in pockets or receptacles formed in the tubes or in the annular space between two concentric tubes, the inner tube acting as a chimney for the combustion products of the heating gas which may be assisted by compressed air or oxygen.  The tubes may be flat in cross section, they may be arranged horizontally, they may be filled with broken silica or like material which becomes incandescent and fluorescent when heated, and they may contain ingredients, other than gases, for varying the colour effect.  The electric heating elements may be arranged at both ends of the tubes or with the convolutions separated to allow of the passage of the rays produced, and the heat supplied may be thermostatically controlled.  A direct or intermittent discharge current may be employed, and sealed conductors may be led into the tubes.