I have made a number of general remarks regarding the character of product delivered by crushers of various types, and under different conditions of operation. Generalities are of value only if we have some standard to which comparisons may be referred; therefore, we should like to present more specific information on the kind of product to … Read more
Operational Characteristics: The method of operation has a considerable effect upon the nature of the product. When minimum fines are a requirement, the hammer mill should always he operated in closed circuit with a screen, or screens; the circulating load should be fairly high; speed should be as low as is consistent with physical structure of … Read more
The hammer mill is the best known and by far the most widely used crushing device employing the impact principle of breaking and grinding stone. Thus far we have described machines which do a portion of their work by impact, but the only machine described in which this action plays an important role was the … Read more
Although its brief period of popularity passed some thirty-odd years since, and only a few sets were installed before interest reverted to other types, the high-speed double roll crusher developed by Thomas A. Edison shortly before the end of the last century warrants a place in any discussion-of crushing equipment. In 1960, the largest machine … Read more
A sectional view of the Dodge jaw crusher here below. The mechanism of this machine is so simple that it is hardly necessary to enlarge upon what can be gained from an examination of the cut. In one respect, the Dodge machine is a reversal of the actions we have been discussing; its movable … Read more
As impact crushing becomes more prevalent in the production of friable as well as some harder types of aggregates, it is natural for those not completely familiar with the process, or recent improvements in technology, to wonder why impactors are being specified in situations previously often considered uneconomical or, at best, marginally feasible for this … Read more
The drop weight test is a common laboratory measurement used to determine the comminution characteristics of rock samples. A common metric derived from a drop weight test is a value “A×b”. Another common metric that is derived from the SMC Test™ variant of a drop weight test is a “Drop Weight Index”, abbreviated as DWi. … Read more
The feed to a crusher should not contain an excessive amount of fine material; this could be stated a little more definitely by saying that it should not contain an excessive amount of material smaller than the crusher product size. Just what constitutes an “excessive amount” depends of course upon several factors, chief among which … Read more
