THE EXTRACTION OF JUICE BY MILLS. 



piecemeal, each mill is driven by its own engine ; the advantage of the single 

 motor type lies in the synchronized working of each unit and in economy in 

 steam and supplies and labour. 



The Three-Roller Mill. The first mill with three rollers with 

 the centres arranged at the angles of an isosceles triangle was made in 1794 

 by Collinge ; in its modern form the headstock or housings on which the 

 rollers are supported may be considered as derived from a rectangle of rather 

 less height than breadth, gaps or openings for the insertion of the gudgeons 

 of the rollers being arranged symmetrically on the top and sides of the 

 rectangle. In Fig. 102 is shown in outline in half elevation the evolution of 

 the conventional form of headstock ; a represents a solid or rigid headstock of 

 massive construction and characterized by an exceedingly flat vertical angle. 

 The difficulty of removing a roller led to the insertion of a distance piece in 

 the shoulder of the headstock, the horizontal strain being taken up by a bolt 



passing therethrough, as shown at b ; the modern form of headstock is seen 

 at c, where the set screws controlling the horizontal outward movement of 

 the bottom rollers are replaced by caps bearing directly on the brasses on 

 which rest the roller gudgeons ; the caps are held in place by heavy T headed 

 bolts recessed into the headstock. 



In all these patterns tensile strains occur in the headstock which is 

 constructed of material unsuited therefor. The radical improvement is due 

 to Rousselot, a French engineer, of Martinique, who, while retaining the 

 form shown at c, passed the side cap bolts through the headstock whereby 

 the horizontal strains are taken up by the bolts which are constructed of 

 material adapted for that purpose. 



In the original Rousselot mill four side cap bolts were employed ; these 

 passed without the vertical bolts ; indifferently four vertical bolts may be used 

 between which pass the horizontal or Rousselot bolts; another modification 



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