16 BULLETIN 1370, U. S. DEPARTMENT OF AGRICULTURE 
If the juice tank is partitioned ito three compartments, one 
compartment full of juice can settle for about half an hour before — 
being drawn into the evaporator. While the juice is settling in this 
compartment the evaporator is being supplied with a previously | 
settled lot and juice from the mill is running into the third com- | 
partment. Care in removing as much as possible of the impurities — 
which will settle out of the cold juice before running it into the — 
evaporator, will be well repaid by the improved quality of the sirup. | 
A pipe connection not less than three-fourths inch in diameter, | 
equipped with a gate valve, to lead the juice from the juice tank into | 
the evaporator by gravity, forming a vertical U, and partly buried | 
under the ground, instead of passing directly across to the evaporator, | 
gives an uncbstructed eee around the pan. The discharge end — 
of the tank is slightly lower than the other end, so that it may be | 
completely drained. A second hole, fitted with a plug, is used for | 
draining and washing. A thin cover to fit this tank will assist in } 
keeping out insects and trash. 
This method of milling and handling juice is applicable regardless | 
of the equipment used for evaporation. It is inconvenient, however, | 
and comparatively expensive to shelter a horse-driven mill, on account | 
of the space required for the sweep. | 
EXTRACTION OF JUICE © 
Careful adjustment before starting is necessary in small power } 
mills to obtain good extraction and avoid loss and delay from the } 
breaking of paris. Setting the small front roll too close to the large | 
roll prevents the mill from taking the cane readily. A clearance | 
space between the front roll and the large roll of approximately | 
three-eighths inch permits the cane to enter the mill promptly and | 
keeps it from being cut up before it reaches the last roll. The clear- | 
ance space between the last small roll and the large roll should be} 
about one-sixteenth inch. With this setting of a 3-roller mill and | 
full-capacity feed, the cane is squeezed fairly dry, an extraction of } 
per iey 60 per cent being obtained. The speed of the mill] 
should be regulated according to the recommendation of the manu- | 
facturer. It is usually about 27 feet per minute for the large roll, } 
equivalent to 10 to 12 revolutions per minute for the average small- | 
pone mill. As the size of the mill increases, the number of revo- ] 
utions per minute of the mill should decrease. The engine speed 
for the types commonly used varies from 375 to 425 revolutions per }: 
minute. | 
Table 6 shows the theoretical yield of sirup per ton of cane from} 
juice at different densities when various percentages of extraction } 
_ are obtained. | 
In seasons of normal rainfall, with efficient 3-roller power-driven |i 
mills, sirup makers may expect about a 60 per cent extraction from} 
the Louisiana Purple and Ribbon varieties of cane—that is, out of} 
every 100 pounds of cane stalks about 60 pounds of juice. Although} 
the percentage of total solids is not identical with the number of }- 
degrees indicated on the Brix hydrometer scale, the solids content} | 
of the juice may conveniently be expressed in terms of this scale.) 
This is usually 14° to 16° Brix—that is, the juice has approximately 
14 to 16 per cent of dissolved solids, the remaining 84 to 86 per 
cent being water. When the apparent solids content of such juice 
is expressed in terms of the scale of the Baumé hydrometer, it 18) P 
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