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The first important development in the move to adapt the gyratory crusher to fine crushing was the debut of the Superior McCully fine-reduction crusher, which was brought out by the Power & Mining Machinery division of the Worthington Co. a few y years before the Allis-Chalmers Co. took over these crushers. This machine was designed along lines identical to those of the standard Superior Mc.Cully crusher with one important exception: instead of the orthodox tapered top shell of the standard machine, the new crusher was fitted with a cylindrically bored shell, the concaves being vertical and reversible. The crushing head was flared correspondingly, this additional flare resulting, for a given size receiving opening, in a head of much larger diameter, For example, whereas the standard crusher with 10-in. receiving opening has a head diameter of about 27 in. at the bottom, the corresponding dimension for the 10-in.reduction crusher is about 40 in. Eccentric speeds were increased, and throws were adjusted for operation at close settings. Originally these machines were fitted with straight-face concaves; later the concaves were tapered t both ends to distribute the wear better; eventually non-choking concaves became standard equipment.
It would be difficult for us, and tedious for the reader, were we to attempt to chronicle all of the development work, some of it successful and some not, which went on in the decade following the end of the First World War One important contribution to the art was the high-speed, direct-connected Newhouse crusher, which introduced a new principle of crushing for cleanness and uniformity of product.
Some 20 years ago the principle of the widely flared crushing head was combined with widely flared crushing head was combined with some other new and radical departures from current practice, and the cone crusher entered the reduction crushing field. Two interesting innovations incorporated in this machine were (1) an unusually large throw and (2) a spring loaded and ad-throw and (2) a spring loaded and adjustable crushing bowl.
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