. The Bell System technical journal . e last third. The wateris literally exploded out of the pulp in this process and leaves a soft porousinsulation which is easily stripped from the wire. Electrostatic capacitancevalues of about .072 mf. per mi. on 24-gauge cables are obtained with thismethod of drying and improved centering of the wire and roundness ofinsulation. These values are practically the same as those obtained withwrapped paper. At wire insulating speeds of 140 feet per minute the insu- INSULATION OF WIRE WITH PAPER PULP 93 lation is dried in approximately 11 seconds. Since in case
. The Bell System technical journal . e last third. The wateris literally exploded out of the pulp in this process and leaves a soft porousinsulation which is easily stripped from the wire. Electrostatic capacitancevalues of about .072 mf. per mi. on 24-gauge cables are obtained with thismethod of drying and improved centering of the wire and roundness ofinsulation. These values are practically the same as those obtained withwrapped paper. At wire insulating speeds of 140 feet per minute the insu- INSULATION OF WIRE WITH PAPER PULP 93 lation is dried in approximately 11 seconds. Since in case of a shutdownthe wire is immediately burned oflf, a band of nichrome tape is kept in thefurnace at all times so that the wires can be tied to it and carried throughfor restringing. Broken wires are strung in by tying them to adjacentwires to be carried through. Reeling up the Finished Wire Because it is necessary to shift from full to empty spools without shuttingdown the machine, dual take-up positions are supplied just as dual feed. Fig. 8—Insulated wire take-up positions are used. The take-up spools are rotated through a slipping discclutch, the pressure on the clutch being controlled by the tension in the reaching the take-up spool the wire is passed over a tension drummade up of two capstan pulleys separated by a movable housing enclosingand fastened to a coiled clock spring. By running the wire first around onepulley then reversing it by passing it around a pulley on the spring housingand then around the second capstan pulley any tension variation in the wirecauses the spring housing to rotate. The rotation of this housing is com- 94 BELL SYSTEM TECHNICAL JOURNAL municated by a system of rods to the clutch so that it tends to speed up orreduce the speed of the take-up spool. With the long coiled spring woundto a definite tension a predetermined pull on the wire can be spools are driven simultaneously side by side through suitable sp
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
