CASTOR-OIL INDUSTRY. 13 



tities of moisture are present. These quantities vary with the 

 character of the material as well as with the way in which the 

 moisture is held, that is, whether or not the moisture is internal and 

 evenly distributed throughout the kernels or oil-bearing particles, on 

 the one hand, or whether, on the other hand, the moisture is distrib- 

 uted over the surfaces of the particles. 



To obtain the former condition, the beans are heated in an atmos- 

 phere highly charged with moisture in order to prevent drying out, 

 while in the latter case they should be heated in a dry atmosphere 

 with ample facilities for the removal of moisture. In order, then, to 

 add the proper amount of moisture for optimum crushing conditions, 

 a jet of live steam should play into the descending current of material 

 just before it enters the expeller. Such operation has the added 

 advantage of (1) increasing the quantity of oil obtained and (2) 

 securing the economical advantage of using the latent heat of steam 

 to effect the heating of the beans just previous to their delivery to 

 the expellers, thus economizing in the heating operation. Such pro- 

 cedure, of course, gives a dry interior to the oleaginous material and 

 a wet surface. 



With further application to improved castor-bean technology, it 

 is evident that this drying effect on the beans would improve and 

 greatly simplify decortication by rendering the seed coats more 

 easily separated from the kernels. 



The heaters are located close to the presses in order to prevent loss 

 of heat and to avoid heating the beans for a longer time and to a 

 higher temperature than is absolutely necessary. The lower the 

 temperature to which the beans are subjected and the less the 

 moisture in the oil, the better is the finished product. Heat darkens 

 the oil and moisture increases the acidity. 



PRESSING. 



In the past, plate presses and cloths were used for castor-bean 

 crushing. On account, however, of the nonfibrous character of the 

 beans with their attendant property of "creeping" under pressure, 

 the cloths would break and the meats would squeeze out. When 

 castor beans are crushed hi such hydraulic presses to give a cold- 

 drawn oil, it is stated that a yield of about 17 pounds of oil to the 

 bushel is obtained. Regrinding the cake and heating to 180° to 

 200° F. for a second pressing yields an additional 3 pounds of oil, 

 leaving about 5.5 per cent of oil in the cake. These figures probably 

 refer to the 46-pound bushel, but the quality of the oil is not up to 

 that from cage presses or expellers. Pressures great enough to yield 

 17 pounds of No. 1 oil per 46-pound bushel are liable to introduce 

 objectionable impurities. However, with pressure sufficient to yield 

 16 pounds of No. 1 oil, this oil need not be discounted. 



