Developments in the Manufacture of Lead-Covered Paper-Insulated Telephone Cable

T h i s p a p e r describes d e v e l o p m e n t s in t h e m a n u f a c t u r e of lead covered paper insulated telephone cable c o m p l e t e d d u r i n g t h e past three years. T h e i n t r o d u c t i o n describes t h e m a n n e r in w h i c h cable is used in t h e t e l e p h o n e system a n d briefly outlines t h e m a n u f a c t u r i n g processes a n d e q u i p m e n t a s t h e y existed a b o u t three years ago. T h e n e w d e v e l o p m e n t s are t h e n treated in considerable d e t a i l , t h e most o u t s t a n d i n g of w h i c h are t h e a p p l i c a t i o n of w o o d p u l p i n s u l a t i o n direct on t h e wire instead of spirally w r a p p i n g m a n i l a rope r i b b o n p a p e r ; new e q u i p m e n t for v a c u u m d r y i n g a n d s t o r i n g cable in w h i c h a large storage r o o m of u n i q u e c o n s t r u c t i o n is p r o v i d e d w i t h c o n d i t i o n e d air at a relative h u m i d i t y of .5 per cent at 100° F . ; t h e central m e l t i n g of large q u a n t i t i e s of lead a l l o y a n d its d i s t r i b u t i o n t h r o u g h p i p i n g systems to a n u m b e r of lead presses; i m p r o v e d a n d larger s h e a t h i n g presses; a n d precision electrical testing of t h e finished cable. M o s t of these i m p r o v e m e n t s are i n c o r p o r a t e d in t h e new B a l t i m o r e C a b l e P l a n t of t h e W e s t e r n Electric C o m p a n y .