18 



CASEIN. 



These rotary driers are suitable where cheap plant is the 

 prime consideration, rather than the drying of large quanti- 

 ties of material at a low temperature. 



FIG. 8. Passburg's Vacuum Drying Plant. 

 (Z Airpump. D = Steam Inlet.) 



The Passburg vacuum drier (Fig. 8) consists of a cast or 

 wrought-iron case, which can be hermetically closed by doors 

 at one or both ends. The inside is divided into a number of 



