8 BULLETIN" 927, U. S. DEPARTMENT OE AGRICULTURE. 
A double cyclone is now being manufactured which separates the 
seeds from the skins and cores in one operation. 
DRYING THE SEED. 
Before the seed obtained from the operations just described is in 
condition for drying, it is preferable that it be washed and the excess 
moisture removed. As the seed emerges from the cyclone it is cov- 
ered with a mucilaginous, slimy coating, and when placed in rotary 
driers in this condition it sticks to the drying surfaces. This coat- 
ing also prevents satisfactory treatment in the preliminary removal 
of water. It has been found that satisfactory washing can be accom- 
plished by suspending the seed in a stream of hot water and cycloning 
it out of the mixture by using the ordinary breaker cyclones. In 
practice this washing is done as follows : The seed is thrown into a 
funnel set in the inlet part of a centrifugal pump, while a stream 
of hot water, likewise directed into the funnel, carries the seed with 
it down into the pump, where the churning action of the rotor 
breaks up the clumps of seed, suspending each particle separately 
and discharging the whole mass more or less homogeneously into the 
washing cyclone. The seed is discharged through the gate quite 
clean and bright. 
Cyclone waste as it is usually produced contains about 80 per cent 
of water, while the seed contains from 65 to TO per cent. One diffi- 
culty in drying material with such a high moisture content is the 
cost of the operation. To economize in this respect and at the same 
time shorten the period of drying, several methods of moisture reduc- 
tion may be employed. 
A considerable proportion of the excess moisture can be removed 
by pressure. For this purpose small hydraulic presses of the type 
used for pressing out apple or grape juice may be used. Cloths are 
laid on racks, the seed is placed thereon, and the edges of the cloths 
are folded over, thus forming a cake. Several of these, one above the 
other, are placed in the press and hydraulic pressure applied. From 
10 to 15 per cent of moisture can be removed by such treatment. A 
small press may have a capacity of about 400 pounds of wet seed an 
hour. 
Moisture reduction by centrifuging has also been tried. In this 
method 4 the seed is placed in a bag and whirled, as in the ordinary 
type of laundry centrifuge. The use of a bag prevents the packing 
of the seed in the machine and facilitates emptying. The moisture 
content of seed, which originally was about 55 per cent, was found 
to be reduced to about 51 per cent. A centrifuge of ordinary size 
(about 3 feet) will handle approximately 600 pounds of seed an hour, 
*Huelsen [W. A.], 1918. Op. cit., p. 42. 
