LEAD-COVERED PAPER-INSULATED TELEPHONE CABLE 457 



close together, thus saving the space formerly occupied by the small 

 individual melting kettles, and the large central-supply kettles were 

 placed adjacent to the lead storage pit in order to minimize handling. 

 Views of this system now in use at Baltimore are shown in Figs. 25-28. 

 The details of this central lead-melting and distributing system will 

 be of interest to manufacturers using large quantities of lead or lead 

 alloy. Three oil-heated kettles are used (Fig. 25), and pipe and valve 

 arrangements have been set up so that the middle kettle is used for melt- 

 ing and preparing the alloy to the exact composition. The second kettle 



Fig. 25 — General view of melting and supply kettles. 



is used as a main supply and connected up to the distributing system. 

 The third kettle is a spare, and the piping is so arranged that it can be 

 used either as a melting or supply kettle. Each kettle has a capacity 

 of 120,000 lbs. of lead, and the melting capacity of the system is 80,000 

 lbs. per hour. Space is provided for a fourth kettle to take care of the 

 ultimate expansion of the cable plant. 



Each kettle has two sets of low-pressure oil burners installed diag- 

 onally across from each other. An impeller type of vertical pump 

 having its intake about 12 in. above the bottom of the kettle, and 

 driven by a 20 hp. vertical motor, creates sufficient agitation by the 

 circulation of the metal to assure a uniform composition. 



