Tube Mill of Hard Materials

Tube mills are heavy machinery which reduce material in size through rotary motions.Essentially, they consist of a horizontal or slighty inclined grinding tube and face covers through which the grinding stock is fed in and discharged.
Mills in which the grinding stock is reduced in size by means of loose grinding bodies (balls or rods) are referred to as ball or rod tube mills."SAG" mills (semi autogeneous grinding mills) operate with a reduced number of grinding bodies. Autogeneous pipe milling machine (AG grinding mills) are steel tube mills which reduce the material in size without grinding bodies.The various types of support include neck bearing arrangements, external support, and a combination of these. The type of support selected in each case depends on the pipe mill manufacturers and the trunnion diameter, and less on the grinding stock For economic reasons, hydrodynamic or hydrostatic sliding bearing arrangements are almost exclusively used for trunnion diameters of more than > 1800 mm. For some years now, trunnions with diameters of < 1800 mm have increasingly been supported in rolling bearings in order to save energy and/or to increase operational reliability. Usually, spherical roller bearings are chosen as they can compensate both misalignments between the support points and tube deflections.
This facilitates filling in and removing the grinding stock through the hollow trunnion. Spherical roller bearings with a tapered bore are used for a neck bearing arrangement. The bearings are mounted either directly onto a tapered trunnion, or onto a cylindrical trunnion by means of a wedge sleeve. The mounting of the neck bearings is facilitated by the hydraulic method.