Our newly developed quality for flecking rolls has proved its value for many years. It is a trend-setter. The material is a static cast special alloy iron of our indefinite chill quality class. An important point here is that the cast iron is molten of diver's special pig iron qualities in a cold-blast cupola furnace & Rotary furnace. The surface hard nesses of these qualities are adjustable to a range of 400 ….600 HV. The decline on hardness is minimal and even with a 20% reduction in diameter the surface hardness will still remain on the same level as with the initial diameter. FILED OF APPLICATION:-
1) In all oil and grease flaking roll systems and for all ranges of comminution where a high surface activity of the milled stock on grounds of the surface-to-volume ratio is to be achieved and where relatively high pressure and cutting forces (abradant forces) are exerted.
2) As smooth rolls in oil milling, e.g. soybeans, sunflower seed, pea nuts, guar gum, rape, sesame coco, palm seed, etc. FUNCTION:-
Merely clear chill cast rolls were formerly used for the above applications. In a chill cast roll, a surface relief will be generated after a given period of service which is due to the extreme difference in hardness of the individual structural constituents. The surface then assumes the “orange peel” effect, and, in spite of there being ripples, it will still be absolutely smooth. The outcome hereof generally is an unsatisfactory disutegetion of the cells and compounded cells together with the effect this has on both yield and effectivity.
Our special indefinite chill qualities are inherently “self-surfacing”. The microscopically fine distribution of graphite in the surface generates the micro porosity that causes a certain basic roughness and gripping capacity covering the entire surface. By its particle size, structure and hardness, the grinding stock itself generates the appropriate roughness and gripping capacity of the roll surface to match each individual application. These rolls therefore also offer a superior capacity for drawing in the grinding stock at the nip and for retaining this property without maintenance.
The grinding stock is drawn in uniformly and rolled out evenly to flicker of one thickness across the full width of the barrel. These properties are retained without maintenance during a long period of service.
On strength of the excellent thermal conductivity of the material over the full roll cross-section, hot spots and resulting pitting, wrapping and /or progressive deterioration of the roll surface are prevented.
it may, of course, not go unmentioned in this context that these superior properties of the roll material can only be fully utilized if all marginal conditions are met, that is-the rolls must be aligned to be absolutely parallel, the differential speed of the rolls must be correct, the grinding stock in feed must be uniform.