CRUSHING AND PULVERIZING MACHINERY. 



433 



TABLE 176. 

 SIZES, POWER, ETC., OF GATES CRUSHERS. 



TABLE 177. 

 ESTIMATED COST OF CRUSHING BY GATES CRUSHER.* 



Class 3. Rolls. 



In the group of crushing machines here considered the material is 

 crushed between two or more cylinders which revolve in opposite direc- 

 tions. These cylinders may be plain-surfaced, longitudinally fluted, 

 or toothed, according to the character of work they are expected to 

 perform. As the fineness of the product is regulated chiefly by the 



* Richards, R. H. Ore Dressing, vol. 1, p. 50. 1903. 



