CANE SUGAR. 



The Horizontal Tube Apparatus. The horizontal submerged 

 tube apparatus differs from the above in that the steam or vapour is contained 

 within the tubes, the juice under treatment being outside ; a longitudinal 

 section of this form is shown in Fig. 161. The evaporating tubes are from 5 

 to 6 feet long, and are supported by vertical tube plates placed about 12 inches 

 from the end; steam enters at the side at/, passes through the tubes, and after 

 condensation is trapped at h ; to facilitate the passage of the water the tubes 

 are often set at a slight incline. It will be seen that the level of the juice 

 in the vessels is, relatively, much higher than in the vertical type. To prevent 

 ^ntrainment losses a very capacious steam chamber is placed over each vessel ; 

 the vapour main leads from this steam chamber to the calandria of the 

 following effect. Plants of this type are not usually made by English firms, 

 who prefer the vertical form ; they are made to a certain extent in America, 

 and are very largely used in Austria and Russia. 



FIG. 162. 



In this type of evaporator the incondensible gases are swept forward by 

 the steam and collect in the space at the end of the tube run, whence they are 

 removed through i ; removal of the gases is much easier in this form of 

 apparatus than in the vertical tube design. 



In Fig. 162 is shown a longitudinal section of a cylindrical Rillieux 

 apparatus, as made by the Newhall Manufacturing Co. ; it differs from other 

 plants in the low vapour space above the boiling liquid ; losses due to entrain- 

 ment are prevented by the horizontal baffle plate at a a and by the vertical 

 plates at 1 1 ; these last extend only half-way across the shell and are attached 

 alternately to opposite sides. This apparatus conforms very closely to the 

 original Rillieux design. 



292 



