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BELL SYSTEM TECHNICAL JOURNAL 



(Fig. 10). Their construction is such that if an occasional lump or 

 break occurs in the sheet it does not cause clogging of the polisher. 

 Polished wet insulation carries about 70 per cent water by weight, 

 which has to be driven off by heat. The drier consists of a 25-ft.-long 

 electric box-type furnace, with heating elements extending the full 

 length of the top, and additional heating elements in the first 8-ft. 



Fig. 7 — Twisting and quadding machine. 



section of the bottom. These elements are thermostatically controlled 

 so that the temperature of the furnace can be set so as not to cause 

 charring of the insulation as it passes through the drier (Fig. 11). Two 

 spooling positions are furnished at the take-up for each wire, so that 

 as soon as one spool is full, the wire can be shifted to an empty spool, 

 and the full spool removed (Fig. 11). In this way, no shutdowns for 



