58 Materials and Their Handling 



may run as high as 200 feet for the lighter cla^ 

 of material. See illustration l", -icing this page. 



Another type of revolving conveyor which is 

 sometimes used is a plain cylinder revolving on an 

 inclined axis. The material lying along the bot- 

 tom is carried up the side to a point where it 

 drops back toward the bottom. Since it cl: 

 vertically, and the axis of the cylinder is inclined, 

 it will not drop back in the same place on the 

 cylinder, but a trifle farther along. The repeti- 

 tion of this process moves the material from one 

 end to the other. Its progress is, of course, si 

 but it is an excellent device for combining drying 

 or roasting with transportation. The most famil- 

 iar cases of this type are the long revolving kilns 

 used in the cement mill. 



Chain Conveyors. One of the principal types 

 of conveyor is the chain type, where chains run- 

 ning on pulleys carry scrapers, aprons, or buckets. 

 This type of conveyor is very flexible, has tre- 

 mendous carrying capacity, can be used for almost 

 every type of material, and will transport it either 

 vertically or horizontally for distances up to 650 

 feet. There are many types of chains and attach- 

 ments, designed for all sorts of purposes. Four 

 widely used types are the drag chain, scraper, 

 apron, and bucket conveyors. 



The Drag Chain Conveyor. The drag chain 

 carries prongs or projections which pick up the 

 material and push it along slides or drag it along 

 a track. Examples of this type are drag chain 

 hoists for moving logs along a runway and the 



