. Le journal technique de Bell System . hanté entre les quatre colonnes à la plaque de la presse. Le vérin à eau de 34 in. De diamètre est muni d'un boulonnage de plomb en acier. La connexion s'effectue entre le cylindre d'eau et une pompe hydraulique hy, Fig. 23, fournissant de l'eau à une pression maximale de CÂBLE TÉLÉPHONIQUE ISOLÉ EN PAPIER RECOUVERT DE PLOMB 455 5500 lb par pouce carré Les quatre colonnes en acier qui supportent ces pièces de fonderie ont un diamètre de 12 po. Le vérin en acier exerce une pression d'environ 59,000 lb. Par scj. Po. Sur le plomb pendant l'extrusion. Au niveau du sol de la presse se trouve une plaque en acier moulé qui porte un s.
2131 x 1172 px | 36,1 x 19,8 cm | 14,2 x 7,8 inches | 150dpi
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. The Bell System technical journal . unted between the four columns at thetop of the press. The 34 in. diameter water ram has the steel lead rambolted to it. Connection is made from the water cylinder to a hy-draulic pump, Fig. 23, supplying water at a maximum pressure of LEAD-COVERED PAPER-INSULATED TELEPHONE CABLE 455 5500 lb. per sq. in. The four steel columns supporting these topcastings are 12^ in. in diameter. The steel ram e.xerts during extrusiona pressure of approximately 59, 000 lb. per scj. in. on the lead. At thefloor level of the press there is a cast-steel plate which carries a steelspacing block upon which the die block rests. Above the die block is awater-jacketed lead cylinder which is exactly centered over the feedorifice of the die block. The die block and lead cylinder are held in placeon the cast-steel plate by four 2 in. bolts. All these parts are station-ary on this press, facilitating handling and inspection, and insuring thatthe cable core always enters and leaves the die block at the same angle.. Fig. 23—Lead press hydraulic pumps. The concentricity of the sheath is affected not only by the contourof the extrusion chamber, including core tube and die, but also by themanner in which heat is applied; and the thickness is affected bytemperature and speed of extrusion so that the human element is animportant factor, and it is necessary to have thoroughly trained andreliable operators on this kind of work. Temperature indicators areused to show die-block temperatures, and the temperature of themolten lead is automatically controlled and recorded. Aside from increasing output, many studies have been made todetermine the exact mechanism of lead extrusion, the relative flow oflead in difterent parts of the extrusion block, the effect of applicationof heat at different points, etc. As the lead-covered cable leaves the press, it is wound upon either 456 BELL SYSTEM TECHNICAL JOURNAL wood or steel reels, depending upon its type. A full reel may wei
