57 



the only important kind of mills on the Ameriran mark(>t. this end is 

 not secured, for the pulp is all brought into contact with metal sur- 

 faces. With the "oreif" machine this is not the case to the same 

 extent. A further disadvantag-e of the grater mill, of pci-haps luore 

 importance from a practical standpoint, is tliat the best grater mills 

 will not continue to prepare the pomace in the l)cst manner unless the 

 grater knives are frequenth' reground. This reiiuires time and skill, 

 and is a distinct drawback to their use in the ordinary country factory. 

 The "greif mill, on the other hand, can be adjusted foi- fine or coarse 

 pomace, as ma}^ be desired, in a minute, and it has the still moi'c impor- 

 tant advantage of reducing the fruit to pomace by bruising or crushing 

 the tissues. 



The "greif "' mill in general 

 aspect appears not unlike many 

 American hand or small power 

 mills, but in the essentials it is 

 entirely ditierent. The fruit 

 when thrown into the hopper, 

 falls upon a slotted bottom 

 (fig. 7). This may be made of 

 hard wood or of metal. There 

 is also a board slotted to corre- 

 spond to the bottom at the back 

 side of the hopper, which de- 

 flects the fruit forward, so that 

 it only comes onto the slotted 

 bottom at the front side of the 

 hopper. The crank or driving- 

 wheel is attached to a shaft (d), 

 which rests just over the slot- 

 ted bottom of the hopper, and to this shaft are attached slightly 

 curved arms (r), 6 to 8 inches long, which, as the shaft revolves, catch 

 the fruit and crush it through the slots in the bottom of the hopper. 

 One of these arms can bo seen in the section of tht^ hoi)per shown in 

 figure 8. Thus the fruit is more or less broken before it comes in 

 contact with the crushers. 



The two stone rollers which crush the fruit are shown in perspective 

 and cross section in figure 9, and in situation at '/. figure 8. Thev 

 are made of granite or of millstone grit, and mounted on shafts. The 

 surfaces are cut with a slight spiral corrugation. By use of a regulat- 

 ing screw (fig. 8, /"), one of these rollers can be made to approach the 

 other, so as to regulate the crushing of the fruit as may ])e desired. 

 The French and German operators wish to pulp the fruit as finely as 

 possible without crushing or grinding the seeds. 



Fig. • 



-Slotted bottom of hopper used in "greif" 

 machiiK'. 



