Patent GB-718181-A (GB)
Title: Improvements in and relating to electric lighting fittings for fluorescent dischargelamps
IPC: F21S8/00
Filed: 1951-04-10
Abstract: 718,181. Discharge lamps. WYBORN, E. J., and FELDEN ENGINEERING CO., Ltd. April 10, 1952 [April 10, 1951], No. 8263/51. Class 39(1) [Also in Groups XI and XXXV] A fitting. Fig. 1, for a tubular fluorescent discharge lamp 7 comprises a tubular or channelshaped metal rod 4 which extends substantially over the whole length of the lamp and is adapted to accommodate within its cavity the conductors supplying current to the lamp, two end caps 8 and 9, each of which has a cavity adapted to receive one end of the metal rod 4 and the adjacent end of the lamp 7 so as to hold the lamp in close contact with the rod, and a container 2 attached to the rod 4 and shaped to receive an incandecsent lamp 1 and a holder therefor, the circuit connection being such that the incandescent lamp 1 is in series with the fluorescent lamp 7 and serves as a ballast resistance therefor. The container 2 can be in the form of a cylinder of expanded or perforated sheet aluminium which may be lined with woven glass fibre to act as a diffuser for lamp 1 or in the form of a bowl open towards the ceiling and made from glass or translucent plastic material to act as a diffuser, or can be of opaque material. The container 2 is connected to the rod 4 at its side opposite to the fluorescent lamp 7 and carries at its top a standard lamp cap 3. The rod 4 can be of aluminium ¢ inch wide and is connected to earth or to one side of the mains or to one end of the fluorescent lamp 7 through a high resistance, e.g. 1 megohm, or through a small condenser, e.g. 0.005 mfd., or through both in series. Spring clips of metal or of " Perspex " (Registered Trade Mark) or other transparent material can be used to hold the lamp 7 and rod 4 in close proximity. The cavity in each of the end caps 8 and 9 can be made so large as to accommodate the sockets 5 and 6 of the lamp 7 or each of the end caps can form or incorporate a lamp socket. The lamp 7 may be provided with one or more internal conducting strips, or auxiliary electrodes, or with a pre-ionising coating consisting of a transparent layer of the oxides of cerium and thorium on the inside or outside of the lamp to aid starting. Part of the ballast resistance may be replaced by a series-connected capacity. Two fluorescent lamps connected in series can be supported side by side from two channel-shaped rods connected to a single container for the ballast lamp. The circuit of one form of the invention is shown in Fig. 3 wherein the incandescent lamp ballast 10 is connected between one pole of the current source 11 and one cathode of the fluorescent lamp 12, the other cathode being connected to the other pole. The metal strip 13, which corresponds to the rod 4 of Fig. 1, is connected through the high resistance 14 to one pole of the current source 11, and a radio suppressor condenser 15 is provided in shunt with the lamp 12. The condenser 15 and resistance 14 can be accommodated in the covers of the lamp sockets 5 and 6. The resistance 14 may be replaced by a small condenser or by a condenser and resistance in series or the strip 13 may be connected to earth. The resistance 14 or the condenser 15 may be omitted if the lamp 12 has an internal conducting strip or auxiliary electrode connected to one of the cathodes.