Cross stream cutter

For moving streams of particnlate matter (aggregate matter, slnrries), typically transported nsing conveyor belts or similar horizontal agents (slides, tmcks, railroad cars, etc.), the eqnivalent principal solntion is the cross-stream cutter, as is illustrated in Fignre 3.22. 

Figure 3.22 Two realizations of cross-stream cutter solutions to process sampling involving significantly heterogeneous aggregate materials (broken ore, raw material, powders, intermediates, cement, waste, soil, other). The gravity-driven, rotating cross cutter [left] does not comply with TOS requirements (highly detrimental IDE and lEE), while the automated cross-stream cutter implemented at the terminal end of a conveyor belt [right] can be easily optimized to eliminate all ISEs. See [3,14] for a broad discussion of all issues related to process industry cross-stream sampler principles, and [11,21] for particular details.

Conventional design of most mechanical sampling systems for large tonnages of coal use some form of cross-stream primary cutter to divert the primary increments from the main stream of coal (Figure 2.2). A major advantage of these systems is that they sample coal from a moving stream, and most of them satisfy the principle that every particle in the entire mass has an equal opportunity to be included in the primary increments. 

A correct alternative to the one-dimensional cross-stream slice with parallel sides is a cutter (sampling tool) that rotates around an axis in a circular fashion. In such a case, the cutter must have a radial shape, that is, it must be wedge-shaped, with the cutter edges converging towards the axis of rotation (Fig. 4). This design ensures that material on the outside of the arc, where the cutter moves faster, has the same chance of being in the sample as material near the center, where the cutter moves more slowly. 

FIGURE 8.2 A cross-stream primary cutter. (From Meyers, R.A., Ed., Coal Handbook, Marcel Dekker, New York, 1981.)... 

The primary samples are usually collected by a primary cutter which cuts the full cross-section of the stream in a way similar to that of each compartment in a spinning riffler (Fig. 1) cutting across the falling stream of powder. The design of such cutters is subject to guidelines laid down in several recent publications.2 3 4 5,6 Thus, for example2 ... 

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