Today in 1938, US Patent 2116006 A was issued, an invention of Edouard Thys, for his “Hop and Stem Separator.” There’s no Abstract, although in the description it includes this summary:

The object of the present invention is generally to improve and simplify the construction and operation of separators; to provide a separator which is particularly intended for separating stems from hops; and more specifically stated, to provide an inclined endless conveyor having trough-shaped members extending crosswise thereof, said troughs being divided into small pockets and said pockets being so shaped that the hops when deposited on the conveyor will settle in the bottom portion of the pockets while the stems will stand endwise and project upwardly from the pockets or lie on the surface thereof in a position where they can be readily removed by a revolving brush under which the vation of the hop and stem separating machine.