352 



FIELD OPERATIONS 



then a spray from water pipes wets the material as it is cut 



and turned over. 



Fig. 5 shows a Drake 

 mixer of usual design. 

 The ingredients are 

 dumped in at the far 

 end, and when they are 

 entirely mixed are de- 

 livered down the chute. 

 The Drake mixer is made 

 in various styles. 



Cockburn Mixer. An- 

 other type of continuous 

 mixer, called the Cock- 

 burn mixer, is illustrated 

 in Fig. 6. This machine 

 consists essentially of a 

 long box of square cross- 



FIG. 5 



section, mounted on a 

 substantial iron frame or 

 truck and revolving on a longitudinal axis on friction rollers, 

 as shown. The axis of the box is inclined slightly from the 



FIG 



horizontal. The ingredients are fed in through a hopper or 

 chute, at the upper end, and, as the mixer revolves, the mate- 



