GB697638A - Improvements in or relating to methods of and devices for providing electric lamp bulbs with an inner layer of very small light-diffusing particles - Google Patents

Abstract

697,638. Electric lamp bulbs. PHILIPS ELECTRICAL INDUSTRIES, Ltd. March 12, 1951 [March 15, 1950], No. 5911/51. Class 39(ii) In forming a layer of very fine lightdiffusing particles on the internal surface of electric lamp bulbs by arranging the bulbs over burners which produce a smoke of such particles, e.g. by burning ethyl silicate in oxygen to deposit silicon dioxide, the bulbs 7, Fig. 1, are carried in succession over a series of burners 1, so that the diffusing layer formed in each bulb is built up by a plurality of devices, thereby producing a regular coating. In the example a series of burners 1, fed.in known manner with ethyl silicate and oxygen from conduits 2, 3, are located immediately below bulbs 7 which are supported, neck downwards, in an aligned series of holes 5 in a table 4, and a series of suction cups 10 are supported by a tubs 8 which communicates with a vacuum pump and is arranged to be oscillated above the table 4 through vertical and lateral paths in the directions indicated in Fig. 2, in order to transport each bulb to the several burners. The vacuum is released at the point 5 of the cycle when the bulbs are above the burners, so that the bulbs drop into position, leaving sufficient, clearance for the vacuum cups to return along the path S T above the bulbs, 'whereupon the tube 8 is lowered to position P for the initiation of a further cycle. Alternatively the burners may be arranged in a circle.