MODERN MACHINERY. 



303 



In the above machine five screens of perforated metal, 

 all with differently-sized holes, can be used at one time 

 for classifying or grading the several sizes of berry. The 

 coffee passes from the feed hopper to the top screen, 

 which is generally a screen with large holes which allows 

 all the coffee to pass through it and the large sticks and 

 other large foreign matter to pass over the end of the 

 screen into the spout at the front of the machine and 

 thence into a box or other receptacle, A sheet-iron 

 apron below the screen carries the coffee to the beginning 

 of the next screen, and the remaining four screens classify 

 or grade the coffee into large flats, peaberry, medium flats 

 and small flats. These four grades then fall into four 

 separate suction trunks at the back of the machine, 

 where an exhaust fan operates with different power on 

 each grade, removing from the coffee the light sticks, 

 lighter black beans and quaker beans ; in fact, everything 

 which is lighter in weight than each grade of good coffee- 



