268 



The Potato 



jets of water are thrown upon it from pipes arranged 

 above. This water detaches the starch granules from the 

 pulp, and the granules, being small, are carried through 

 the meshes of the gauze, while the pulp is left on the 

 screen and ejected finally at the lower end. 



The starch which 



is carried through 

 by the water falls 

 in large tanks, vary- 

 ing in size from 20 

 to 40 feet in length 

 and width and from 

 6 to 8 feet in depth. 

 The starch settles 

 to the bottom very 

 quickly and the red- 

 dish-colored super- 

 natant water can 

 be drawn off. In a 

 few hours the starch 

 has all settled in a 

 hard, compact mass 

 at the bottom of 

 the tank. The proportion of starch and water is such 

 that 4 inches of starch is overlaid with about 6 feet of 

 water. 



The crude starch obtained in this tank is then thrown 

 into another tank of a similar size which is fitted with a 

 revolving stirrer; water is added in large quantities at 

 the same time and the starch is beaten into a cream and 

 again allowed to settle. The interior view of such a tank 

 can be seen in Fig. 26. This process washes the starch 

 and removes the larger portion of impurities. 



P^iG. 26. Starch washer (interior view). 



