The performance of hammer mill was evaluated taking into consideration hammer mill capacity, efficiency, particle size distribution , power, energy requirement and operational cost.
Hammer Mill Capacity Table. Hammer Crusher. The Jeffrey Miracle Hammer Crusher is designed for the reduction of large pieces and large capacities of limestone, shale, slag, and cement rock. The larger sizes are built to take steam shovel size limestone, crushing it into pieces 1, 2, 3, or 4 and under, in one operation, the one unit ...
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The number of hammers in a mill is variable, depending on the fineness looked after as well as the mill capacity, however, in general the higher the number of hammer, the finer will be the product, but the capacity will also decrease. The mill can be more or less wide depending on the number of rows of hammers mounted on the shaft. Each row of hammer is separated from the other with a spacer plate. The length of the hammers can also be adjusted. If the hammer length is increased, coming close...
Long term maintenance costs are considerably less expensive than similar capacity roller mills. Sudengas hammermills are available with various feed and discharge formats to fit most applications. Standard Features. 6 x 18 diameter full circle grinding chamber. Direct drive hub assembly with 15 hammers.
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Because all these variables that we have noted have an influence upon the capacity of the hammermill, it is impossible to present a comprehensive tabulation of capacity ratings which can be relied upon for any and all materials. We can however do so for any one material, as we did for the Fairmount crusher. It is convenient and logical that this should be a medium limestone in this case also, because hammermills are applied extensively to crushing, and pulverizing, that kind of rock. Above is the approximate capacity ratings of the various sizes of hammermill , on medium limestone, and for various grate bar spacings. Unless the prospective hammermill user has operational data on which to predicate his selection of a new machine for some specific service, the safest procedure is to have his material tested, either in the field or in the laboratory, in a mill of the type he proposes to install.
The shattering effect of the blows delivered by hammers travelling at velocities as high as 200 Feet/Second is conducive to both of these results. It is natural to expect that gradation of the hammermill product would vary somewhat for materials of differing friability, and results verify this expectation. Furthermore, speed has a definite influence upon product gradation; high speeds increase fines, and vice versa. The effect of impact at extremely high speed is, on friable material, almost explosive, the action being more aptly designated as pulverizing, rather than crushing. Lower impact velocities have a more moderate breaking effect, and if the material is able to clear the crushing chamber before it is struck too many times, the low speed hammermill will turn out a fairly uniformly graded product on material of average friability.
What is intended to take place inside a hammermill is the uniform, efficient reduction of the material introduced into the grinding chamber. This particle reduction occurs as a result of the impact between a rapidly moving hammer and a relatively slow moving particle. If sufficient energy is transferred during the collision, the particle breaks and is accelerated towards the screen. Depending on the particle size and the angle of approach, it either passes through the screen or rebounds from the screen into the rapidly moving hammers again. As materials move through the grinding chamber they tend to approach hammer tip speed. Since reduction only occurs when a significant energy is transferred from the hammer to the particle , less grinding takes place when the particles approach hammer tip speed. Many manufacturers incorporate devices within their mills to interrupt this product flow, allowing impact and reduction to continue. Tear circle hammermills have a more positive, natural redirection of product at the inlet than full circle design machines. While the basic operational concepts are the same for all hammermills, the actual unit operating conditions change rather dramatically depending on the materials being processed. Grains such as corn, wheat, sorghum and various soft stocks, like soybean meal, tend to be friable and easy to grind. Fibrous, oily, or high moisture products, like screenings, animal proteins, and grains like oats and barley, on the other hand, are very tough and require much more energy to reduce. Consequently, the hammermill setup that works well for one will not necessarily work for the other. The following discussion covers such factors as tip speeds, hammer patters and position, horsepower ratios , and air assist systems. Little space is devoted to screen sizes since processing variables would make any hard and fast statements nearly impossible.
This machine operates on the principle of reducing the material by striking it while in suspension, as opposed to attrition. The material is fed into the top of the machine and falls into the path of the rapidly revolving hammers. Different degrees of reduction may be had by simply varying the speed of the machine.
This unit is of extra heavy construction and consequently is well adapted for severe duty. The hinged breaker plate is adjustable while operating and is fitted with a heavy renewable liner. Shafting is high carbon forged steel and is fitted with discs which are of heavy plate and cast steel, carefully balanced. Screen bars may be high carbon steel, tool steel, or manganese steel as desired. Jeffrey Swing Hammer Pulverizers have heavy cast iron frames and are lined with renewable chilled iron liners. Hammers are made of materials best suited for the particular job. Highest grade radial ball bearings are used and they are readily accessible for inspection and oiling. This keeps power consumption to a minimum and maintenance and repair part costs are extremely low, even for most types of heavy duty.
A metal catcher attachment is available for use on all sizes of pulverizers where tramp iron may be encountered. It may be specified when unit is ordered or obtained later and installed when need arises. Let us make recommendations for your pulverizer installation. Information required is type of material to be handled, tonnage size of feed, and desired size of product. Belt or motor drive may be used as required.