22 BULLETIN" 328, U. S. DEPARTMENT OP AGRICULTURE. 



SPECIAL CLEANING DEVICES. 



SPIRAL CLEANER FOR REMOVING ROUND SEEDS FROM GRAIN. 



Machines especially devised for removing round seeds from grain 

 and screenings are advertised in various grain papers and catalogues 

 of firms manufacturing grain-cleaning machinery. One machine used 

 to separate vetch from wheat or rye consists of an upright spiral 

 tube divided into several sections. The grain containing vetch is 

 fed into the top and follows its course down the spiral steel tubes. 

 The round seed travels more rapidly and finally gets into the outer 

 tube or section, while irregularly shaped seeds and lighter matter 

 move less rapidly and are discharged from the openings of the tubes 

 nearer the center. Such machines require very little space, no power 

 (being operated by gravity), and scarcely any watching. The 

 capacity of these machines for cleaning grain thoroughly is very 

 small, as only a few bushels per hour can be cleaned. They are very 

 useful in separating vetch from rye or wheat where clean grain is 

 desired for seeding purposes, but they have insufficient capacity for 

 use in grain elevators or flour mills. 



THE COCKLE CYLINDER. 



In addition to the grain cleaners usually found in mills for pre- 

 paring wheat for grinding, specially constructed machines known as 

 cockle cylinders are frequently installed for the purpose of removing 

 from the grain corn-cockle seed and other foreign matter and seeds 

 of similar size and shape. 



Although these machines are comparatively inexpensive, a con- 

 siderable quantity of wheat consisting of broken, small, and shriveled" 

 kernels is taken out in removing the corn cockle. This increases the 

 mechanical loss that results from cleaning grain, and a portion of 

 the corn-cockle seed is left in wheat after being cleaned with the 

 cockle cylinder. 



MECHANICAL ANALYSES OF CORN-COCKLE SCREENINGS. 



Table XI gives the mechanical analyses of four samples of corn- 

 cockle screenings secured from country mills. Sample No. 73719 

 represents screenings removed in cleaning wheat with the cockle 

 cylinder. Half a pound of screenings was obtained from each bushel 

 of wheat cleaned. Analysis of this sample showed that but 1.3 per 

 cent was corn cockle and 93.6 per cent was wheat. In the other 

 three samples a relatively small percentage of the screenings con- 

 sisted of corn cockle, while a high percentage was wheat. Sample 

 No. 80994 represents corn-cockle screenings removed by the cleaning 

 machinery in general use in country mills, and the other three samples 

 are screenings removed from wheat with cockle cylinders. Such 



