THE EXTRACTION OF THE JUICE BY MILLS 



201 



FIG. 96 



with a corrugated roller. The rotary trash turner applied to a standard form 

 of housing also appears in a patent of Fletcher (14562 of 1891). 



As is explained in detail later, the pressure between the top and the back 

 roller of a mill is much greater than that between the top and the front 

 roller ; consequently the top roller is 

 thrust against the jaw of the top gap 

 on the feed side. The first attempt 

 to compensate for this unequal strain 

 is seen in Hall's inclined housing, 

 Fig. 94, the king bolts being arranged 

 parallel to the supposed resultant of 

 the forces acting on the top roller. 



In Hedemann's design (U.S. patent 

 1016301, 1914), Fig. 95, compensa- 

 tion for the side thrust is also at- 

 tempted, with the addition that a 

 variable position of the resultant is 

 allowed, this position being determined 

 by trial and error. Bolk's design 

 (13471 of 1912), Fig. 96, leaves the 

 two lower rollers rigid and allows for 

 the adjustment of the top roller in a 

 vertical and a horizontal direction by means of wedges above, below, and 

 on the sides of the journal bearings. The king bolts pass outside the 

 bearings, and the rollers are driven by an idler pinion. 



In Fig. 97 is shown Fogarty's mill (U.S. 535577, 1895), which replaces 

 the ordinary housing with a circular framing. 



Mill Rollers. The mill rollers consist of a shaft, upon which is fixed a 



shell forming the roll proper. Fig. 98 

 shows in half section a common type 

 of top and bottom rollers. In modern 

 practice the shaft, a, is forced into 

 the shell, b, in an hydraulic press, 

 permanency of attachment being 

 secured by contact and by a key. To 

 prevent juice entering between the 

 shaft and -the shell, juice rings seal 

 the opening. The inner ring, c, is 

 put on in halves, and over it is shrunk 

 on an outer ring, d. The top roller 

 is supplied with flanges to prevent 

 bagasse being extruded sideways. 

 The flange may be a part of the 

 roller as shown, but is better bolted 

 to the shell, so that the upper and 

 lower rollers may be interchangeable. 

 The wear and tear of the shells 



forms a large item in the upkeep of a mill. In place of renewing the whole 

 shell, a common practice in Hawaii is to remove a four-inch ring from the 

 shell, and to shrink on a new outer part, which is further secured to the 

 remainder of the shell by dowel pins. As the new portion wears down it 

 may again be renewed. 



FIG. 97 



