Abstract: A rotary-type mill is provided with a system for charging powder to a mill under seal from atmospheric air, the system being comprised of a sealable loading conduit and a valve assembly. The valve assembly, which controls the opening to the mill, is disposed in part in the sealable loading conduit, and is operable without breaking the seal to the atmosphere. In addition to permitting charging and operations of the mill in a protective environment, the system is designed for gravity-dependent essentially unencumbered vertical entry of feed to the mill and for minimization of the problem of wear of machine parts during operation of the mill.

Abstract: A batch-type rotary grinding mill operable under seal to the atmosphere is provided with a discharge system which permits discharge of material from the mill under seal and without disturbing the seal in the mill. The discharge system comprises at least one discharge chute which is sealably secured to the shell wall, spiraling adjacent to the shell and traversing the shell wall from one end to the other. The material is discharged from the discharge chute via a hollow trunnion which, preferably, contains a conveyor to aid in passing the material out of the mill into an environmentally protected device.