loose condition preparatory to passing it through the riddles and sieves.
This is done in the disintegrators, which consist essentially of annular rows
of prongs carried on a disc, which revolves at a very high speed. The sand
Fig. 63.—Grinding Mill
A, Runners. B, Pan. c, Chilled bottom plates. D, Scrapers. E, Shoot for discharge.
is beaten and thrown about violently. The prongs stand vertically ^ (fig.
64) or lie horizontally in different designs. They are carried on a single
disc, or two discs face each other with the prongs on one entering the spaces
on those of the other, the rotations being in opposite directions. Or