A conveyor I 14 may deliver the crushed product from the receptacle 11 to sizing mechanism, illustrated as screens 115 and 116 of successively coarser mesh, and compartments 117,coal crushing 118 and 119 to respectively receive the more fine particles which pass through the screen 115, the somewhat coarse particles which pass through the screen 116 and the particles too large to pass through the mesh of either screen.It will be understood that when uncrushed rock passes through a crusher, the crushed product comprises pieces of widely variant sizes.
Even when the cooperating jaws of the crusher are so widely spaced as to pass relatively large pieces, the crushed product will usually contain a considerable proportion of relatively small particles, the pieces being of sizes ranging from that of mere dust to the maximum size that will pass the crusher.Frequently in practice desired characteristics are close uniformity of size,stone quarry equipment absence or low proportion of fines and effective use of the power delivered to the crusher, and my method of operation gives advantageous results from all of these standpoints.
The wider setting between the cooperating jaws on the first side of the crusher results in a relatively easy direct delivery (through the screen 1 3) of a considerable portion of the product from the first side and this portion, passing the screen 103, preferably does not go at all to the second side of the crusher. Were the material passing through the screen 103 to pass with the coarser material from the first side of the crusher through the second side of the crusher, it would be crushed to an undesirable fineness, and while still in the crusher would have deleterious packing action around still uncrushed pieces, making more difficult the crushing of these yet uncrushed pieces. This no doubt explains one of the reasons for the advantageous results obtained.