MODERN BLAST FURNACE PRACTICE 91 



nace top and there quickly emptied by lowering the bell form- 

 ing the bottom of the bucket. This very ingenious arrange- 

 ment is in use only at Duquesne; possibly a more typical 

 furnace top is that in use at the Youngstown furnaces. Before 

 considering the top, however, let us first take up the method 

 of assembling the burden. The skip filling car commands 

 the full length of the ore bins. It is a side dumping car elec- 

 trically operated and carrying its own scales. This car de- 

 livers the ore from the bins directly to the skip car, which 

 rests in a water tight tank immediately in front of the car. 



The hmestone is delivered from the bin directly into the 

 skip car, while the coke is also delivered directly into the 

 skip from the bin. The skip, holding about 15,000 pounds 

 of ore, is now carried to the top of the furnace, where it is 

 discharged into the receiving or supplementary hopper which 

 is designed to hold a skip load. The small bell closing this 

 hopper is now lowered by means of the 14-inch oscillating 

 cylinder actuating a counter-weighted beam; the descend- 

 ing column of ore is evenly distributed around the main 

 furnace hopper, w^hich holds a 30,000 pound ore charge; 

 this bell is operated by the 16-inch cylinder. The bell rod 

 of the small bell is hollow and through it passes the solid 

 rod of the large bell. In operating this arrangement the upper 

 bell is always closed during the period the lower bell is discharg- 

 ing stock into the furnace; the seal so formed prevents the 

 waste of the furnace gases. In the charging apparatus 

 built by the Brown Hoisting Machinery Co., the skip dumps 

 into a central receiving hopper carrying an inclined spout, 

 which delivers the ore at any given point on the periphery 

 of the bell; as successive charges are dumped into this re- 

 ceiving hopper, it is caused to rotate through any desired 

 angle. It is evident that a furnace charged in this manner 

 closely approaches the hand filled furnace so far as facihty 

 of controlling stock distribution on the bell is concerned. 

 Skips are operated by steam or electricity; in either case an 

 automatic slowing device is used which causes the skip to 

 come to rest gradually and without shock. 



Another interesting part of the equipment of the modern 

 blast furnace is the casting machine. In dealing with the 



