Patent GB-976472-A (GB)
Title: Method and apparatus for producing glass filaments
IPC: C03B5/24
Filed: 1962-05-22
Abstract: <PICT:0976472/C1/1> <PICT:0976472/C1/2> <PICT:0976472/C1/3> A method of continuously processing glass batch material into continuous filaments comprises feeding the batch into a furnace near one end, refining the molten glass in the furnace by causing it to progress to the other end in a series of closed current loops, flowing the refined molten glass from the said other end into a forehearth, withdrawing the molten glass from <PICT:0976472/C1/4> <PICT:0976472/C1/5> the forehearth as a plurality of fine streams and alternating the streams to filaments by winding the streams on to rotating collectors.  The formation of the closed current loops is effected by blowing a fluid through the molten glass and/or by establishing temperature gradients in the furnace.  A number of melting and refining furnaces 46 are arranged in parallel transversely of a building 10, each provided with an exhaust stack 48 and recuperator 50, feed chargers 100 at each side, the fore end of the furnace leading to a neck 60, bridge 61 and branches 56 to 59 in H formation.  The branches 56 to 59 from the furnaces 46 extend in parallel through a room 64 and each branch has a number of rectangular openings 300 in which a feeder 68 of platinum or rhodium alloy is arranged, the streams of glass through the feeders 68 being collected and packaged on rows of winding machines 28 and 30 either side of a chamber 36 lying below the room 64.  Glass batch material is fed for one or more storage bins 105 by a screw-type conveyer 104 to a hopper 101 and charger 100 and is fed through openings 99 at each side of the furnace 46. The batch entry is electrically controlled to maintain a substantially constant amount of glass in each furnace, each batch charger 100 having a control valve 102.  The furnace is fired by fuel gas, mixed with air preheated in the recuperator 50, through a supply manifold 110 to burners 108 set in blocks 109, each side of the furnace, the burners 108 being regulated to assist in forming closed current loops, the region indicated at 184, Fig. 6, being a hot zone maintained at about 100 DEG F. higher than at the batch charging end and about 50 DEG F. higher than at the delivery end.  The floor 86 of the furnace is provided with two rows 172, 174 of tuyeres transversely spaced between the two ends of the furnace and the hot zone 184 and steam or compressed air is blown to the tuyeres 172, 174 through pipes 178 so as to bubble through the molten glass to give additional closed current loops, as shown by the arrows 180, there being a gradual shifting of the glass from the batch entry to the exit to the forehearth, where the molten glass passes under a shimmer block 194.  To reduce the temperature of the glass in the channels 210 in neck 60, ceiling blocks 249 can be adjusted to vent the channel and the temperature is then maintained along the channel 212 of bridge 61 by burners 262.  The temperature of the glass in the side channels 250 of branches 56 to 59 is then reduced by heat sinks 308 and maintained by burners 292 so that it is the same for each stream feeder 68. Each feeder 68 comprises two rows of tips 304 to give " fine " streams of glass which are collected into strands 72, 73 and alternated by winding on collectors 336.