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The "Hydrocone" crusher (Fig. 8), was designed primarily with a view to achieving top performance in the field of fine-reduction crushing. It has also been adapted to what is designated simply as "fine-crushing," which extends into a range below that 01'dinarily defined by the term "fine-reduction."
Although the eccentric speeds of the various sizes of this type are not quite so high as the speeds used for the Newhouse crusher, the Hydrocone crusher definitely rates as a high-speed machine, its product comparing quite closely to that of the former type, for equal close-side settings.
Probably the outstanding feature of the Hydrocone crusher is the hydraulic support, from which its name is derived and which is clearly shown in the sectional view. This device makes it possible to adjust the crusher to any desired setting within its range in a matter of seconds; adjustments may be made while the crusher is running, although the feed must be shut off before operating the adjusting pump. An accumulator in the hydraulic system provides protection against tramp iron or packing.
Fig. 9 shows a diagram of the Hydrocome crushing chamber. A comparison of this chamber with those previously discussed is interesting. It will be noted that the choke-point has been raised far above the discharge level, in fact, to a point noit far below the nip-point for the recommended maximum one-way feed dimension. By virtue of the decided flare of the head, and the corresponding flare of the top shell bore, the line-of mean-diameters slopes sharply away from the crusher centerline. From some distance above the discharge point the angle between head and concave is very acute; in facts, at the open-side position of the head this zone is almost parallel.
For recommended operating conditions, i.e., for safe combinations of throw and setting, and with screened feed, this type of crushing chamber does not
approach anything like a choke or near-choke condition. For the combination shown in the diagram the ratio of volume reduction is almost 1:1 from zone 0-1 zone 2-3 at the chokepoint; consequently, if the crusher is given a screened feed (as all fine-reduction crushers should be) the reduction in voids by the time the chokepoint is reached cannot very well reach serious proportions.
The diagram shows the standard chamber. With screened feed these crushers will operate at close-side discharge settings equal to the throw of the head at the discharge point (usually spoken of a “eccentric-throw”.)
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