Corn-and-cob Crusher.—A machine of the well-known coffee-mill type is shown in Figure 7. This machine, which may be driven from above or below, instantly seizes and crushes the entire ear, though it may be adjusted to shell corn, and also to break it in preparation for burr stone grinding. It has a hopper fitted over its mouth, and a collecting bowl beneath, with directing-spout; it can be constructed to rotate the nut or runner either right-hand or left-hand, as may be preferred.
The Case Uertical-stone Mill (61.7, Jig. 5) consists of an iron case in two sections, which are fastened tightly together by three bolts. The portion of the case to the left (in the illustration), when the bolts and the lower arm of the shaker-rod are removed, may be drawn backward on the rollers, which are seen on the under side of the case. The portion on the right, which revolves on trunnions, may be lowered to the floor, for dress ing the stones. The discharge for the mill is on the side of the case (seen in the cut on the left-hand portion), and at the rear of the machine is the driving-pulley, which is fastened to the steel shaft by set-screws. On two sides of the hopper is a slide for governing the feed; so that when it is desired a partition may be placed through the centre of the hopper and the slides adjusted to feed grain of different kinds and in predetermined proportions. This arrangement is a desirable feature when grinding mixed grains, as corn and oats. The stones are elastically bedded, so as to yield when a hard substance gets between them, thus avoiding injury, but they will not run together should the feed stop. Our illustration is a perspective view of the general construction of the single mill.
The cyclone Pulverizer (pl. 7, fig. 6), which reduces materials to dust in violently opposing currents of air, consists of two winged pro pellers revolving in reverse directions in an enclosing case. There is adapted to the upper part of the body of the machine a hopper for receiv ing the material to be fed to the machine, and also an adjustable feeding mechanism, which drops the material between the propellers, each of which is fixed upon a shaft extending within the casing of the machine from opposite sides. The shafts are driven by belts in opposite directions at a high speed, thereby creating a " cyclone," which violently dashes the particles to be reduced against one another, thus effecting their complete pulverization with comparatively little wear on the operating machinery.
From an opening in the top of the casing of the machine a connection is made with the grading-box and the dust-chambers. This box is divided by partitions into compartments, which are at varying distances from the mill, and into each of which the floating dust drops. As the velocity of the air entering at the propeller-shafts and passing through the case toward the dust-chamber lessens, the heavier atoms of dust fall first, while the slowing current so graduates the product that the finest is carried into the dust-chamber, where in the comparatively still air it is permitted to settle. The mill completely comminutes the most obstinate substances, such as iron-slag, phosphate-rock, silica, and green bones, and is equally effective in reducing oily, viscous, and fibrous substances, such as fish-scrap, clay, soapstone, dried tankage, and blood from slaughter-houses.
The Scientific (61. 8, figs. is intended for grinding any kind of grain for feed, and will grind ear-corn with the shucks on or off, reducing the shucks, cobs, and corn all to any desired fineness. Figure r2, which exhibits the front part of the casing cut away, gives a good general idea of the interior arrangement. The material is fed into the hopper and is caught by the lugs on the two rollers, which revolve toward each other, the motion being communicated by means of a gear-wheel engaging a pinion on the main shaft. By these crushers the material is broken into pieces, which fall upon the crushing-conveyer on the main shaft, where they are further broken and conveyed to the grinding-plates shown in Figures 8 to Tr. One of these plates is stationary, and the other is attached to, and revolves with, the main shaft. The shaft moves easily back and forth in its bearings; so that the running plate can be set close to, or away from, the stationary plate by a screw, by which means the grinding will be either coarse or fine, as desired. At the end of the shaft is arranged an anti-friction block, which takes all end pressure, and the bearing at that point is self-lubricating; hence there is little danger of excessive friction. The mill is very strong, and the plates are capable of grinding large quantities of material before wearing out; new plates can be easily and quickly inserted. This mill, of which numerous sizes are made, grinds all small grains, such as shelled corn, oats, screenings, etc., as well as car-corn, and by it excellent corn-meal can be produced.