Abstract: To construct a tube mill such that a simple and compact circulation grinding system can be created therewith, with little outlay in terms of machinery, that can also manage higher stock circulation rates without high operating costs, a tube mill is disclosed whose drop-delivery housing consists of two spaced stationary non-rotating side faces, between which a rotatably mounted material conveyor ring is arranged, which can be rotated; whereby a sifting space with a dynamic sifter and/or a static sifter is integrated in this so constructed drop-delivery housing.

Abstract: In order to create a wear-resistant surface armoring suited for autogenous wear protection for the rolls of high-pressure roll presses for pressure disintegration of granular material using nap bolts (grid armoring), which also comprises a high serviceable life span even under the effect of high-pressure loads, it is proposed to give the nap bolt the shape of a mushroom, whose head projects outward from the roll body and whose shaft is sunk into the corresponding recess or bore of the roll body in such a way that an open space remains between the base of the bore and the lower end of the shaft of the bolt.

Abstract: An improved roller press for the high pressure interparticle crushing of a pulverulent material and the method of operating including opposed parallel horizontal crushing rollers forming a high pressure crushing nip between them and forcing air from the material drawn into the nip, a product delivery stack above the nip and an offset lower wall portion above the nip and laterally of the stack forming an exposed sloping surface of the material for the escape of air being pressed out of the material passing into the nip, in one form exposed surfaces are on both sides of the nip and the exposed surfaces may be controlled by adjustable gates to vary the area and slope of the exposed surface, and a subatmospheric pressure may be applied to the material for aiding in the pressing of air from the material drawn into the nip.

Abstract: A grinding system for grinding brittle material such as used in the manufacture of cement including a high pressure roller press operated with high pressing forces to form interparticle crushing with incipient cracks in the interior of the particles including recirculating a portion of the material delivered from the press to a sifter locating the sifter directly above the nip and delivering the sifted material downwardly into the nip retaining the structural height of the system low and delivering fresh stock laterally directly into the nip of the roller press to merge with the sifted material entering directly into the nip of the roller press.