Roll mills such as these are referred to as being of the type where the pair of rollers pressed against each other is driven--by means of a driving unit--with circumferential speeds differing from one another, the pair of rollers either being in the nature of roll refiner mills, or being of a flaking mill type. In these cases, the rollers may have a comparatively slight difference in speed. The German publication DE-A 36 31 077 provides a device of the kind under consideration, and describes a flaking mill in which a mixing device is arranged inside the feeding compartment to compensate for segregation of the material to be ground during transportation. In the case of wet and sticky products liable to agglomeration, the mixing device, which is formed by mixing arms, will rather bring about a segregation of the product than the desired uniform mixing effect of the material to be ground. This occurs even then when such transfer units are used which tend to favor the mixing of the product.
From European patent document DE-PS 33 03 014 a supply unit is known, which, swiveling backward and forward over the length of the rollers of a calendar, feeds the product to be ground immediately into the nip. This supply unit may be suitable for the feeding of separate granulates into the nip. However, for the processing of bulk materials, the provision of a belt conveyor for uniform feeding cannot be recommended, not least because of lacking space inside the feeding compartment.
It is an object of the present invention to design an apparatus for feeding particulate material to a roll mill which can be used for a plurality of bulk materials, particularly for material that is hard to mix, with the apparatus needing little space and being of a simple design as well as preventing unequal roller wear to a high degree.