CASTOR-OIL INDUSTRY. 19 
at the middle, and 0.025 inch at the discharge end, all bound together 
by massive clamping bars. A horizontal screw rotating on the axis 
of the cage carries the charge of oilseed forward and discharges it 
at the other end of the cage over a cone, which may be moved in or 
out, according as greater or less pressures are sought. The charge of 
oil-bearing material is introduced through a hopper into the cage or 
barrel and the slowly rotating worm engages it and carries it forward. 
As the charge reaches the small aperture around the cone it encoun- 
ters more resistance, which operates to build up pressures within the 
barrel. These pressures are regulated by varying the size of the 
aperture between the cone and the walls of the barrel. The farther 
the cone is moved into the barrel, the smaller is the aperture through 
which the cake may be discharged. Inasmuch as the screw moves 
forward at a constant rate and thus delivers a continuous quantity 
of material to the : 
barrel, it follows that 
the oil yield is readily 
controlled by simply 
adjusting the cone and 
varying the size of the 
discharging aperture. 
For ordinary materials — 
these expellers can be 
adjusted to yield cakes 
containing as low as 5.5 
per cent of oil. 
These machines are 
very generally used for 
peanut and copracrush- 
ing and for many other oleaginous materials, all of which, however, 
must havesuch fiber content as to present sufficiently effective binding 
Fig. 11.—A cage carriage. 
_ properties to prevent squirting of the meats through the interstices 
of the bars. There is, of course, great wear of the parts, but since 
these are standardized they can readily be supplied. It has been 
_ stated that with properly cleaned material and with right care of the 
machine the upkeep is no greater than the cost of the cloth in plate 
presses. An average for more than seven prewar years shows the 
upkeep to have been about $100 for each machine per annum. 
Figure 12 represents a battery of such machines set up somewhat 
as they appear in good factory installation. Manifestly, the small 
labor charge attendant on their operation is much in their favor, 
together with the cleanliness and mechanical simplicity of their 
action. One man can operate the whole battery, and even more. 
