6 



BULLETIN 904, U. S. DEPARTMENT OF AGRICULTURE. 



end of the vat. Most of the germs float on the surface and over the 

 edge of the vat at one end. The bulk of the germ material is thus 

 removed, but in the larger plants the remaining material is put 

 through another floating vat and additional germs are separated. 

 The germs, together with a lot of starchy water, are then run through 

 reels having perforated copper sides, with the perforations about 

 1| mm. in diameter. Here they are thoroughly washed to remove 

 all starchy particles. The washings from these reels are run through 

 a second set of reels having finer perforations, which catch the small 

 germ fragments that passed through the first reel. The quantity of 

 germ material thus recovered is very considerable. 



The corn material, which because of its greater gravity remains 

 in the floating vats, is ground wet, and the starchy material is reduced 

 to a fine condition. It is then sieved and washed repeatedly. These 

 starch washings, together with those from the germ reels, are run 



over long shallow ta- 

 bles, where the starch 

 is allowed to settle. 

 The process there- 

 after is one of drying, 

 but in the case of 

 boiling starches the 

 drying is preceded 

 by chemical treat- 

 ment. 



The husk and bran 

 from which the 

 starch has been 

 washed are run 

 through moisture expellers to remove part of the moisture and 

 are then mixed or churned with the concentrated steep water from 

 the steeping vats. This water, which contains considerable quan- 

 tities of water-soluble proteins, is previously pumped into a vacuum 

 tank and evaporated under reduced pressure. The evaporation is 

 accomplished under a vacuum of about 26 inches, part of which is 

 obtained by passing all the waste water of the plant through a 

 special attachment, like a Venturi tube. The higher vacuum is 

 secured with a power pump. As above stated, this protein water, 

 to which is also added in some plants the gluten which tabled out 

 at the lower end of the starch settling tables, is mixed with the feed 

 material and the mixture pumped through filter presses. The press 

 cakes from these filters are broken up by running' them through 

 mills. The material is then sent through driers. These driers are 

 also used for drying the germs and will be described in that connec- 

 tion. After becoming partially dry the material, which has become 





Fig. 5.- 



-Machine for wet degerminating. In this machine one plate 

 is stationary. 



