Roll crushers have a theoretical MAXIMUM reduction ratio of 4:1. If a 2 inch particle is fed to the roll crusher the absolute smallest size one could expect from the crusher is 1/2 inch. Roll crushers will only crush material down to a minimum particle size of about 10 Mesh (2 mm). A roll crusher crushes using compression, with two rolls rotating about a shaft, towards the gap between the rolls. The gap between the rolls is set to the size of product desired, with the realization that the largest feed particle can only be 4 times the gap dimension. The particles are drawn into the gap between the rolls by their rotating motion and a friction angle formed between the rolls and the particle, called the nip angle. The two rolls force the particle between their rotating surface into the ever smaller gap area, and it fractures from the compressive forces presented by the rotating rolls. Some major advantages of roll crushers are they give a very fine product size distribution and they produce very little dust or fines. Rolls crushers are effectively used in minerals crushing where the ores are not too abrasive and they are also used in smaller scale production mining of more abrasive metal ores, such as gold. Coal is probably the largest user of roll crushers, currently, though. Coal plants will use roll crushers, either single roll or double roll, as primary crushers, reducing the ROM coal. Usually, these crushers will have teeth or raised forms on the face of the roll. (Roll crushers used for minerals and metal ores have smooth faced rolls.)
The particles are drawn into the gap between the rolls by their rotating motion and a friction angle formed between the rolls and the particle, called the nip angle. The two rolls force the particle between their rotating surface into the ever smaller gap area, and it fractures from the compressive forces presented by the rotating rolls. Some major advantages of roll crushers are they give a very fine product size distribution and they produce very little dust or fines. Rolls crushers are effectively used in minerals crushing where the ores are not too abrasive and they are also used in smaller scale production mining of more abrasive metal ores, such as gold. Coal is probably the largest user of roll crushers, currently, though. Coal plants will use roll crushers, either single roll or double roll, as primary crushers, reducing the ROM coal. Usually, these crushers will have teeth or raised forms on the face of the roll. (Roll crushers used for minerals and metal ores have smooth faced rolls.)
GIDC Vatwa, Ahmedabad Plot No. 291/2, Pancharatna Estate, Opposite Shayona Industrial Estate, Near Ramol Cross Road Near Ramol Over Bridge, Phase 4, G. I. D. C., Vatva, GIDC Vatwa, Ahmedabad - 382445, Dist. Ahmedabad, Gujarat
I have madea 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 be expected from crushing equipment under average operating conditions. Much of the data on which sizing/designcurves and tables are based comes from operations involving those two very important types: gyratory and jaw crushers; therefore these curves and tables are more nearly representative of the work of these types than of rolls or hammermills. They may be used for these latter types however if due allowance is made for peculiarities of each type, as pointed out in the descriptions of the different machines.
The preparation of a set of product gradation curves involves a considerable amount of work in the collection of the necessary test data, and a certain degree of discrimination in sorting such data and weeding out erroneous results. There are several reasons why no set of product gradation curves can be regarded as more than reasonably close approximations. First among these is the variation in physical structure of the many materials for which crushers are used; rocks exhibit a high degree of rugged individualism in their reaction to crushing. This variation is frequently quite pronounced between different ledges in the same quarry.
Gradation of the crusher feed also has its effect upon the product analysis. This is true even of screened feed, although deviations from the average are not likely to be so wide as they are for unscreened material, such as quarry-run or mine-run rock. We have commented on other variable factors, such as choke versus regulated feed, straight versus curved concaves, and so forth.
Fortunately, most materials do follow a certain definite gradation pattern and, by averaging a large number of test results, it is possible to plot a group of curves which can be classed as fairly close approximations. Even though approximate, these curves are of great value in crushing-plant design, or in the solution of problems concerning additions or alterations in the plant flowsheet. They simplify the problem of selecting secondary and tertiary crushers, as well as elevating and conveying equipment, and they are invaluable in the calculation of screen sizes. In short, they eliminate much of the old-time guess work in the preparation of the plant flowsheet.
Gyratory and jaw crushers are always rated at certain open-side or close-side discharge settings. In order that we may select the particular curve, of a group of curves, which will most nearly represent the product of a crusher having any given discharge setting, it is important to know approximately what percentage of the total output will pass a screen opening of equal dimension. It was universal practice in past years to designate such screen openings as ring-size for the very logical reason that the leading screen of that day, the revolving type, was, almost without exception, fitted with sections having round holes. Now that the vibrating screen, with its wire cloth or square-punched steel plate sections, has pre-empted the field there is no longer any excuse for adhering to the ring-size product designation.Above is alist of the approximate percentages of product passing a square opening test sieve whose holes are equal to the discharge setting of the crusher. Several different conditions are tabulated, and each condition is accompanied by estimates for four different classes of material.
In gravel pit operations it will usually be found that some one of these listed base rocks will predominate, and no great error will be introduced if this predominant rock is used as the basis for product calculations. Most base rocks will be close enough in physical structure to one of the listed varieties so that the percentages can be used for them without serious error. The same statement applies to the product gradation curves to be discussed. It must be remembered that the entire process of securing and compiling data of this nature is, at best, one which is susceptible of only approximate results.
It was formerly the custom to consider one set of product gradation, or screen analysis, curves as being suitable to represent the products of both primary (unscreened) and secondary (screened) feeds, making no allowance for the undersize material which is always present, to some extent, in quarry-run and mine-run materials. The average quarry does not produce as much of this undersize rock as the average mine, but the usual practice in mining operations is to scalp off most of the undersize ahead of the primary crusher, whereas this practice is the exception rather than the rule in quarry operations. As a matter of fact, where the secondary crushers are fitted with straight concaves, or jaw plates, as used to be standard practice, the dif-ference between product curves on screened and unscreened feed was not significant, and no great discrepancy was introduced by considering them under the one heading.
With the introduction of non-choking concaves in the standard gyratory crushers and reduction crushers, and the development of high speed fine-reduction crushers with high choke points, it soon became apparent that there was a substantial difference in the screen analyses of the two kinds of product, that is, crusher products on unscreened and screened feeds. The difference is especially significant in the lower part of the curve, where undersize in the feed would naturally show up, and where the cleaner breaking of the non-choke crushing chamber would likewise be reflected.
Here above isshown a family of curves for primary crushing of unscreened feed, such as the average quarry-run material in which the undersize (minus crusher setting) rock is present in proportions normally resulting from blasting operations. The same curves may be used for mining operations with stationary bar grizzlies ahead of the primary crusher.
In such operations the amount of undersize going into the crusher will usually be about the same as for the quarry operation without pre-scalping. It should be noted that the test data on which these curves are based were taken from gyratory and jaw crusher operations, but, as we have stated before, they may be used for other types of crushers if allowance is made for the characteristics peculiar to each type. As a matter of fact, so far as crushers of the Fairmount single-roll type are concerned, there is a natural compensation which brings the curves fairly well into line. The Fairmount crusher is inherently a somewhat cleaner breaking machine than either the standard gyratory or standard jaw types, but the class of rock for which the former crusher is largely used is usually subject to greater than average degradation during the blasting and loading operations in the quarry, which tends to level out the difference in crushing performance.Using Crusher and Screen Charts
The method of using the curves is so simple as to require little comment. The vertical axes represent material sizes, which may be taken as either square or round openings; provided of course that the same shape of opening is used throughout any particular analysis. The horizontal axes represent cmmdative percentages passing corresponding screen openings. If we wish to check the product to be expected from a crusher set at some predetermined discharge opening, we first refer to the table showing the approximate percentage of product which will pass an opening equivalent to the crusher setting. This gives us a point in the group of curves which may, or may not, be exactly on one of them. In the latter case we interpolate by following an imaginary curve between the two curves on either side of our point. We can thus tabulate cumulative percentages passing all of the product sizes in which we may be interested. Non-cumulative percentages; which are important because they are used to determine expected amounts of specific products are simply the difference between the upper and lower cumulative percentages for the particular product limits under consideration.
For those not familiar with the use of product gradation curves an example may be helpful. Suppose that a tentative selection of a 3.5 open- side discharge setting has been made for a standard gyratory primary crusher to be used for crushing quarry-run limestone. Referring to the table which lists percentages of product passing an equivalent square opening, we find that 85 to 90% of the crusher product should pass a 3.5 square opening. Choosing the lower percentage, to be on the conservative side,, we follow the horizontal line, denoting the 3.5 product size in the curve chart, over to the vertical line marking the 85% value. We find that the point we have established does not fall directly upon any of the group of curves, but lies so close to one of them that it may be used without appreciable error into our calculations.
Let us suppose that we wish to know how much of the product of our primary crusher will be retained on a 1.5 square opening screen, so that we may estimate the size and number of secondary crushers required to recrush the plus 1.5 contingent. Following the curve down to the 1.5 line, we find that 43% of the primary crusher output may be expected to pass this screen opening; 57% will be retained, which means that we must provide secondary crushing capacity to take care of 57 tons for each 100 tons fed to the primary crusher.
Occasionally it happens that we wish to scalp off a salable product from the output of the primary crusher; for example, a plus 1.5 minus 3.5 material for highway base- rock. The difference between the cumulative percentages at the 3.5 and 1.5 points on the curve gives us the amount, of such product to be expected from the output of the primary crusher This is 85 minus 43, or 42% of the primary crusher product.
If our problem had covered a crushing condition calling for 80 instead of 85%passing the opening equivalent to the crusher setting, we would have found that our point fell exactly on a curve, regardless of what crusher setting we had selected. This is because all of the family of curves are based on the 80% line. Obviously a group of curves might be based on any percentage line, but it is usual practice to choose the 80 or 85% values.
It will be noted that the curves bend upward in very marked fashion above the 75-85% region. This simply reflects the tendency of practically all materials to slab, or spall, to some extent in the crusher. As a matter of fact, product gradation in this upper range (above the open- side setting of the crusher) is of a distinctly uncertain and variable nature, and about all that a group of curves can do is to reflect the general tendency. Fortunately the exact screen analysis in this fraction of the primary crusher output is recrushed in succeeding stages, and all that is required is to know approximately how much of it there will be to recrush.
Although the group of curves we have been considering are intended for calulations involving primary crushing operations, they may also be used for secondary crusher products in those cases where no screening is performed between primary and secondary stages. Such an arrangement is seldom encountered in modern plant design, except where large jaw crushers, set very wide, are followed by a secondary, usually of the standard gyratory type, to reduce further the very coarse output of the jaw crusher to a size which can be handled by the recrushing, screening, and elevating equipment in the balance of the plant. In such cases it is simplest to consider the two-stage set-up as a single machine with discharge opening equal to that of the secondary crusher.
The group of curves on the rightischarted from screen analyses of the products of crushers receiving screened feed. They are useful in predicting the character of output from secondary and tertiary crushers, and are of great value in the preparation of plant flowsheets, and in calculating vibrating screen capacities. Their use in the latter connection will be discussed in the screening section of this series.
There is no need for extended comment on this group of curves; the method of taking off cumulative percentages, and non-cumulative fractions, is exactly the same as for the chart we previously discussed. The difference in the shape of these curves is attributable to the absence of fines in the crusher feed, and to the cleaner breaking action of the modem reduction crusher.
The product gradation curves for screened feed, described under the preceding sub-heading, can be used as a basis for calculating approximate screen analysis of products from closed-circuit crushing stages, but the values cannot be taken directly from the curves.
For example, consider a crusher set to turn out a product 70% of which will pass a 5/8 square opening, and in closed circuit with a screen which is equipped to remove the minus 3/4 product. Thecurve shows that approximately 85% of the crusher product will pass the 3/4 square openings.
Suppose that we wish to know how much minus 0.25 fines we may expect from the circuit.We do not go to the curve which touches the 100 percent ordinate at the 3/4 value; we calculate the percentage from the same curve which was used to predict the proportion of minus 0.75 in the crusher discharge. This curve shows approximately 29 percent of minus 3/4 in the material as it comes from the crusher, or 29 tons of fines in each 100 tons of crusher output. But, for the circulating load, we are only interested in that fraction of the crusher output which will pass the 3/4 screen, which is 85 tons.That part of the product gradation curve which lies below the 85 percent valuerepresents the gradation of the finished product, and 29 tons out of each 85 would be minus 0.25.
Let x equal percentage of minus 0.25 in the finished product, then x:100=29:85 or x = 34.1 percent of minus 0.25 rock from the closed circuit operation. Any other size of product may be estimated in a similar manner. Note that if we had used a curve touching the 100 percent ordinate at the 0.75 value, we would have arrived at a value approximately 50 percent for the minus 0.25 fraction; a value which is obviously erroneous for rock of average characteristics. We will comment on closed circuit crushing, and upon certain assumptions which have to be made in closed circuit calculations, in a later discussion of reduction-crushing.
Although the long established practice of designating crusher products by ring-size is not compatible with present-day screening practice, there are occasions when it is desirable to convert our calculations from one shape of opening to the other. So far as the curves themselves are concerned, once we have established the shape of screen openinground or squarewe can use them for either so long as we stick to one shape throughout the process of taking off percentages-passing. If, as occasionally happens, we have to deal with both shapes of screen opening in the same set of calculations, one or the other of them must be converted to equivalent sizes of the opposing shape. For example, if most of the screen openings are to be square, but one or two of them must be round, the round-hole sizes should be expressed in terms of equivalent square openings.
Inasmuch as the table of crusher settings versus equivalent product percentages is based on square openings, it is necessary to convert to equivalent round openings before this table can be used for such openings.
Below is the information needed to make conversions from round to square holes, or vice versa. The two columns at the left showing equivalent sizes for flat testing screens, are the columns to use in connection with crusher product calculations.Admittedly, listings of equivalent round and square holes, such as we show in this table, can be only approximately correct for the many different materials with which we must deal in crushing and screening computations. The infinite variety of shapes encountered renders absolute accuracy an impossible attainment. Practical experience, however, indicates that the comparisons shown in our table are in most cases close enough for all practical purposes.
Product SizeCorresponding Size Holes Through a flat testing screen Allis-Chalmers vibrating screenRevolving Screen Round holes Square holesRound holes Square holesRound holes 1/83/325/321/85/32 3/83/327/323/161/4 1/43/149/321/41/16 1/21/411/321/123/8 3/83/107/163/81/2 1/43/81/23/163/18 1/21/101/41/25/8 3/21/25/81/1811/10 3/82/1011/106/83/4 11/105/83/411/107/8 3/411/107/83/41 7/83/415/187/81 1/8 17/81 1/1612/101 1/4 1 3/811 2/181 1/181 3/8 1 1/41 1/161 3/81 1/71 2/14 1 3/81 1/81 1/161 1/41 3/4 1 1/21 1/41 3/181 3/81 7/8 1 5/81 3/81 3/41 3/102 1 3/41 1/21 7/81 3/162 1/4 1 7/81 5/821 3/42 3/8 21 3/42 1/81 7/82 1/2 2 1/81 7/82 1/422 5/8 2 1/41 15/182 3/82 1/162 3/4 2 3/822 1/22 1/82 11/16 2 1/22 1/82 6/82 1/43 1/8 2 5/82 1/42 3/42 3/83 5/12 2 3/42 3/82 7/82 1/23 1/2 2 7/82 1/232 5/83 5/8 32 5/83 1/42 3/43 3/4 3 1/42 3/43 1/234 3 1/233 3/43 1/44 3/8 3 3/43 1/443 1/24 3/4 43 1/24 1/43 3/45 4 1/23 7/84 3/44 1/85 1/2 54 1/45 1/44 1/26 1/4 5 1/24 3/45 3/456 7/8 65 1/46 1/25 1/27 1/2 6 1/25 1/275 3/48 767 1/26 1/28 3/4 7 1/26 1/2879 3/8 878 3/47 1/210 8 1/27 1/49 1/47 3/410 1/2 97 3/49 1/28 1/411 1/4 9 1/28108 1/211 3/4 108 1/210 1/2912 1/2
In the quarry, crushing is handled in four potential stages: primary, secondary, tertiary and quaternary. The reduction of aggregate is spread over these stages to better control the product size and quality, while minimizing waste.
The primary stage was once viewed merely as a means to further reduce stone following the blast or excavation prior to secondary crushing. Today, primary crushing is viewed as more important within the balance of production and proper sizing needs. The size and type of the primary crusher should be coordinated with the type of stone, drilling and blasting patterns, and the size of the loading machine. Most operations will use a gyratory, jaw or impact crusher for primary crushing.
In the secondary and subsequent stages, the stone is further reduced and refined for proper size and shape, mostly based on specifications to produce concrete and asphalt. Between stages, screens with two or three decks separate the material that already is the proper size. Most secondary crushers are cone crushers or horizontal-shaft impact crushers. Tertiary and quaternary crushers are usually cone crushers, although some applications can call for vertical-shaft impact crushers in these stages.
A gyratory crusher uses a mantle that gyrates, or rotates, within a concave bowl. As the mantle makes contact with the bowl during gyration, it creates compressive force, which fractures the rock. The gyratory crusher is mainly used in rock that is abrasive and/or has high compressive strength. Gyratory crushers often are built into a cavity in the ground to aid in the loading process, as large haul trucks can access the hopper directly.
Jaw crushers are also compression crushers that allow stone into an opening at the top of the crusher, between two jaws. One jaw is stationary while the other is moveable. The gap between the jaws becomes narrower farther down into the crusher. As the moveable jaw pushes against the stone in the chamber, the stone is fractured and reduced, moving down the chamber to the opening at the bottom.
The reduction ratio for a jaw crusher is typically 6-to-1, although it can be as high as 8-to-1. Jaw crushers can process shot rock and gravel. They can work with a range of stone from softer rock, such as limestone, to harder granite or basalt.
As the name implies, the horizontal-shaft impact (HSI) crusher has a shaft that runs horizontally through the crushing chamber, with a rotor that turns hammers or blow bars. It uses the high-speed impacting force of the turning blow bars hitting and throwing the stone to break the rock. It also uses the secondary force of the stone hitting the aprons (liners) in the chamber, as well as stone hitting stone.
With impact crushing, the stone breaks along its natural cleavage lines, resulting in a more cubical product, which is desirable for many of todays specifications. HSI crushers can be primary or secondary crushers. In the primary stage, HSIs are better suited for softer rock, such as limestone, and less abrasive stone. In the secondary stage, the HSI can process more abrasive and harder stone.
Cone crushers are similar to gyratory crushers in that they have a mantle that rotates within a bowl, but the chamber is not as steep. They are compression crushers that generally provide reduction ratios of 6-to-1 to 4-to-1. Cone crushers are used in secondary, tertiary and quaternary stages.
With proper choke-feed, cone-speed and reduction-ratio settings, cone crushers will efficiently produce material that is high quality and cubical in nature. In secondary stages, a standard-head cone is usually specified. A short-head cone is typically used in tertiary and quaternary stages. Cone crushers can crush stone of medium to very hard compressive strength as well as abrasive stone.
The vertical shaft impact crusher (or VSI) has a rotating shaft that runs vertically through the crushing chamber. In a standard configuration, the VSIs shaft is outfitted with wear-resistant shoes that catch and throw the feed stone against anvils that line the outside of the crushing chamber. The force of the impact, from the stone striking the shoes and anvils, fractures it along its natural fault lines.
VSIs also can be configured to use the rotor as a means of throwing the rock against other rock lining the outside of the chamber through centrifugal force. Known as autogenous crushing, the action of stone striking stone fractures the material. In shoe-and-anvil configurations, VSIs are suitable for medium to very hard stone that is not very abrasive. Autogenous VSIs are suitable for stone of any hardness and abrasion factor.
Roll crushers are a compression-type reduction crusher with a long history of success in a broad range of applications. The crushing chamber is formed by massive drums, revolving toward one another. The gap between the drums is adjustable, and the outer surface of the drum is composed of heavy manganese steel castings known as roll shells that are available with either a smooth or corrugated crushing surface.
Double roll crushers offer up to a 3-to-1 reduction ratio in some applications depending on the characteristics of the material. Triple roll crushers offer up to a 6-to-1 reduction. As a compressive crusher, the roll crusher is well suited for extremely hard and abrasive materials. Automatic welders are available to maintain the roll shell surface and minimize labor expense and wear costs.
These are rugged, dependable crushers, but not as productive as cone crushers with respect to volume. However, roll crushers provide very close product distribution and are excellent for chip stone, particularly when avoiding fines.
Hammermills are similar to impact crushers in the upper chamber where the hammer impacts the in-feed of material. The difference is that the rotor of a hammermill carries a number of swing type or pivoting hammers. Hammermills also incorporate a grate circle in the lower chamber of the crusher. Grates are available in a variety of configurations. The product must pass through the grate circle as it exits the machine, insuring controlled product sizing.
Hammermills crush or pulverize materials that have low abrasion. The rotor speed, hammer type and grate configuration can be converted for different applications. They can be used in a variety of applications, including primary and secondary reduction of aggregates, as well as numerous industrial applications.
Virgin or natural stone processing uses a multi-stage crushing and screening process for producing defined aggregate sizes from large lumps of rock. Such classified final fractions are used as aggregates for concrete, asphalt base, binder and surface course layers in road construction, as well as in building construction. The rock is quarried by means of drilling and blasting. There are then two options for processing the bulk material after it has been reduced to feeding size of the crushing plant: mobile or stationary plants.
When stone is processed in mobile primary crushing plants, excavators or wheel loaders feed the rock into the crusher that is set up at the quarry face, gravel pit or in a recycling yard or demolition site. The crushed material is then either sent to the secondary/tertiary processing stage via stacking conveyors or transported by trucks. Some mobile crushers have an independent secondary screen mounted on the unit, effectively replacing a standalone screen.
The higher the compressive strength of rock, the higher also is its quality, which plays an important role particularly in road construction. A materials compressive strength is delineated into hard, medium-hard or soft rock, which also determines the crushing techniques used for processing to obtain the desired particle sizes.
The materials quality is influenced significantly by particle shape. The more cubic-shaped the individual aggregate particles are, the better the resulting particle interlock. Final grains of pronounced cubic shape are achieved by using several crushing stages. A cubicity showing an edge ratio of better than 1-to-3 is typical of high-quality final aggregate.
As the earths natural resources are becoming ever more scarce, recycling is becoming ever more important. In the building industry, recycling and reuse of demolition concrete or reclaimed asphalt pavement help to reduce the requirements for primary raw materials. Mobile impact and jaw plants are uniquely positioned to produce high-quality reclaimed asphalt pavement (RAP) and recycled concrete aggregate (RCA) for reuse in pavements, road bases, fill and foundations.
Use of RAP and RCA is growing dramatically as road agencies accept them more and more in their specs. But because RAP and RCA come from a variety of sources, to be specified for use by most departments of transportation they must be processed or fractionated and characterized into an engineered, value-added product. RCA or RAP are very commonly crushed and screened to usable sizes often by impact crushers and stored in blended stockpiles that can be characterized by lab testing for use in engineered applications.
Impact crushers are increasingly used for crushing recycling material. Impact crushers are capable of producing mineral aggregate mixes in one single crushing stage in a closed-cycle operation, making them particularly cost-effective. Different crusher units can alternatively be combined to process recycling material. A highly efficient method of processing recycling material combines crushing, screening and separation of metals. To produce an end product of even higher quality, the additional steps of washing to remove light materials such as plastics or paper by air classification and via electromagnetic metal separator are incorporated into the recycling process.
Mobile impact crushers with integrated secondary screens or without integrated screen used in conjunction with an independent mobile screen are ideal for producing large volumes of processed, fractionated RAP or RCA on a relatively small footprint in the plant. Mobile impactors are especially suited for RAP because they break up chunks of asphalt pavement or agglomerations of RAP, rather than downsize the aggregate gradation. Compression-type crushers such as jaws and cones can clog due to packing (caking) of RAP when the RAP is warm or wet.
Contaminants such as soil are part of processing demolition concrete. Mobile impact and jaw crushers when possessing integrated, independent prescreens removing dirt and fines before they ever enter the crushing circuit reduce equipment wear, save fuel, and with some customers, create a salable fill byproduct. A lined, heavy-duty vibrating feeder below the crusher can eliminate belt wear from rebar or dowel or tie bar damage. If present beneath the crusher, this deflector plate can keep tramp metal from degrading the conveyor belt. That way, the feeder below the crusher not the belt absorbs impact of rebar dropping through the crusher.
These mobile jaw and impact crushers may feature a diesel and electric-drive option. In this configuration, the crusher is directly diesel-driven, with the conveyor troughs, belts and prescreen electric-driven via power from the diesel generator. This concept not only reduces diesel fuel consumption, but also results in significantly reduced exhaust emissions and noise levels. This permits extremely efficient operation with low fuel consumption, allowing optimal loading of the crusher.
Jaw crushers operate according to the principle of pressure crushing. The raw feed is crushed in the wedge-shaped pit created between the fixed crusher jaw, and the crusher jaw articulated on an eccentric shaft. The feed material is crushed by the elliptic course of movement and transported downwards. This occurs until the material is smaller than the set crushing size.
Jaw crushers can be used in a wide range of applications. In the weight class up to 77 tons (70 metric tons), they can be used for both virgin stone and recycled concrete and asphalt aggregates processing as a classic primary crusher for natural stone with an active double-deck grizzly, or as a recycling crusher with vibrating discharge chute and the crusher outlet and magnetic separator.
Output for mobile jaw crushers ranges from 100 to 1,500 tph depending on the model size and consistency of the feed material. While larger mobile crushers produce more aggregate faster, transport weights and dimensions may limit how easily the crusher can be shipped long distances. Mobile jaw crushers can have either a vibratory feeder with integrated grizzly, or a vibrating feeder with an independent, double-deck, heavy-duty prescreen. Either way, wear in the system is reduced because medium and smaller gradations bypass the crusher, with an increase in end-product quality because a side-discharge conveyor removes fines. A bypass flap may provide easy diversion of the material flow, eliminating the need for a blind deck.
Jaw crusher units with extra-long, articulated crusher jaws prevent coarse material from blocking while moving all mounting elements of the crusher jaw from the wear area. A more even material flow may be affected if the transfer from the prescreen or the feeder trough is designed so material simply tilts into the crushing jaw.
Mobile jaw and impact crushers alike can be controlled by one operator using a handheld remote. The remote also can be used to move or relocate the crusher within a plant. In other words, the crusher can be run by one worker in the cab of an excavator or loader as he feeds material into the crusher. If he sees something deleterious going into the hopper, he can stop the crusher.
Impact crushing is totally different from pressure crushing. In impact crushing, feed material is picked up by a fast moving rotor, greatly accelerated and smashed against an impact plate (impact toggle). From there, it falls back within range of the rotor. The crushed material is broken again and again until it can pass through the gap between the rotor and impact toggle.
A correctly configured mobile jaw or impact crusher will enhance material flow through the plant and optimize productivity. New-design mobile jaw and impact crushers incorporate a highly efficient flow concept, which eliminates all restriction to the flow of the material throughout the entire plant. With this continuous-feed system, each step the material goes through in the plant is wider than the width of the one before it, eliminating choke or wear points.
For example, a grizzly feeder can be wider than the hopper, and the crusher inlet wider than the feeder. The discharge chute under the crusher is 4 inches wider than the inner width of the crusher, and the subsequent discharge belt is another 4 inches wider than the discharge chute. This configuration permits rapid flow of crushed material through the crusher. Also, performance can be significantly increased if the conveying frequencies of the feeder trough and the prescreen are adapted independently to the level of the crusher, permitting a more equal loading of the crushing area. This flow concept keeps a choke feed to the crusher, eliminating stops/starts of the feed system, which improves production, material shape and wear.
Users are focused on cost, the environment, availability, versatility and, above all, the quality of the end product. Simple crushing is a relatively easy process. But crushing material so that the particle size, distribution and cleanliness meet the high standards for concrete and asphalt requires effective primary screening, intelligent control for optimal loading, an adjustable crusher with high drive output, and a screening unit with oversize return feed.
This starts with continuous flow of material to the crusher through a variable-speed control feeder. Having hopper walls that hydraulically fold integrated into the chassis makes for quick erection of hopper sides on mobile units. If available, a fully independent prescreen for either jaw or impact models offers the ability to effectively prescreen material prior to crushing this allows for product to be sized prior to crushing, as opposed to using a conventional vibrating grizzly. This has the added value of increasing production, reducing wear costs and decreasing fuel consumption.
This independent double-deck vibrating screen affects primary screening of fines and contaminated material via a top-deck interchangeable punched sheet or grizzly, bottom-deck wire mesh or rubber blank. Discharged material might be conveyed either to the left or to the right for ease of positioning. The independent double-deck vibrating prescreen improves flow of material to the crusher, reducing blockages and feed surges.
Modern electrical systems will include effective guards against dust and moisture through double-protective housings, vibration isolation and an overpressure system in which higher air pressure in the electrical box keeps dust out. Simple and logical control of all functions via touch panel, simple error diagnostics by text indicator and remote maintenance system all are things to look for. For crushing demolition concrete, look for a high-performance electro- or permanent magnet with maximum discharge capacity, and hydraulic lifting and lowering function by means of radio remote control.
For impact crushers, a fully hydraulic crusher gap setting with automatic zero-point calculation can speed daily set-up. Featured only on certain mobile impact crushers, a fully hydraulic adjustment capability of the crushing gap permits greater plant uptime, while improving quality of end product.
Not only can the crushing gap be completely adjusted via the touch panel electronic control unit, but the zero point can be calculated while the rotor is running. This ability to accurately set the crusher aprons from the control panel with automatic detection of zero-point and target-value setting saves time, and improves the overall efficiency and handling of the crusher. On these mobile impact crushers, the zero point is the distance between the ledges of the rotor and the impact plates of the lower impact toggle, plus a defined safety distance. The desired crushing gap is approached from this zero point.
While the upper impact toggle is adjusted via simple hydraulic cylinders, the lower impact toggle has a hydraulic crushing gap adjustment device, which is secured electronically and mechanically against collision with the rotor. The crushing gap is set via the touch screen and approached hydraulically. Prior to setting of the crushing gap, the zero point is determined automatically.
For automatic zero-point determination with the rotor running, the impact toggle moves slowly onto the rotor ledges until it makes contact, which is detected by a sensor. The impact toggle then retracts to the defined safe distance. During this procedure, a stop ring slides on the piston rod. When the zero point is reached, the locking chamber is locked hydraulically and the stop ring is thus fixed in position. The stop ring now serves as a mechanical detent for the piston rod. During the stop ring check, which is carried out for every crusher restart, the saved zero point is compared to the actual value via the electronic limit switch. If the value deviates, a zero-point determination is carried out once again.
These impact crushers may feature a new inlet geometry that allows even better penetration of the material into the range of the rotor. Also, the wear behavior of the new C-form impact ledges has been improved to such an extent that the edges remain sharper longer, leading to improved material shape.
The machines come equipped with an efficient direct drive that improves performance. A latest-generation diesel engine transmits its power almost loss-free directly to the crushers flywheel, via a fluid coupling and V-belts. This drive concept enables versatility, as the rotor speed can be adjusted in four stages to suit different processing applications.
Secondary impact crushers and cone crushers are used to further process primary-crushed aggregate, and can be operated with or without attached screening units. These crushers can be used as either secondary or tertiary crushers depending on the application. When interlinked to other mobile units such as a primary or screen, complicated technical processing can be achieved.
Mobile cone crushers have been on the market for many years. These machines can be specially designed for secondary and tertiary crushing in hard-stone applications. They are extraordinarily efficient, diverse in application and very economical to use. To meet the diverse requirements in processing technology, mobile cone crushing plants are available in different sizes and configurations. Whether its a solo cone crusher, one used in addition to a triple-deck screen for closed-loop operation, or various-size cone crushers with a double-deck screen and oversize return conveyor, a suitable plant will be available for almost every task.
Mobile cone crushers may be available with or without integrated screen units. With the latter, an extremely efficient triple-deck screen unit may be used, which allows for closed-loop operation and produces three final products. Here the screen areas must be large so material quantities can be screened efficiently and ensure that the cone crusher always has the correct fill level, which is particularly important for the quality of the end product.
Mobile, tracked crushers and screen plants are advancing into output ranges that were recently only possible using stationary plants. Previously, only stationary plants were used for complicated aggregate processing applications. But thanks to the advancements made in machine technology, it is becoming increasingly possible to employ mobile technology for traditional stationary applications.
Mobile crushers are used in quarries, in mining, on jobsites, and in the recycling industry. These plants are mounted on crawler tracks and can process rock and recycling material, producing mineral aggregate and recycled building materials respectively for the construction industry. A major advantage of mobile crushers is their flexibility to move from one location to the next. They are suitable for transport, but can also cover short distances within the boundaries of their operating site, whether in a quarry or on the jobsite. When operating in quarries, they usually follow the quarry face, processing the stone directly on site.
For transport over long distances to a new location or different quarry, mobile crushers are loaded on low trailers. No more than 20 minutes to an hour is needed for setting the plant up for operation. Their flexibility enables the mobile crushers to process even small quantities of material with economic efficiency.
Mobile plants allow the combination of prescreening that prepares the rock for the crushing process and grading, which precisely separates defined aggregate particle sizes into different end products to be integrated with the crushing unit into one single machine. In the first stage, the material is screened using an active prescreen. After prescreening, it is transferred to the crusher, from where it is either stockpiled via a discharge conveyor or forwarded to a final screen or a secondary crushing stage. Depending on the specified end product, particles are then either graded by screening units or transported to additional crushing stages by secondary or tertiary impact crushers or cone crushers. Further downstream screening units are used for grading the final aggregate fractions.
The process of prescreening, crushing and grading is a common operation in mobile materials processing and can be varied in a number of ways. Mobile crushers with up to three crushing stages are increasingly used in modern quarries. Different mobile crushing and screening plants can be combined for managing more complex crushing and screening jobs that would previously have required a stationary crushing and screening plant.
Interlinked mobile plants incorporate crushers and screens that work in conjunction with each other, and are coordinated in terms of performance and function. Mining permits are under time constraints and mobile plants provide faster setup times. They provide better resale value and reusability, as mobile plants can also be used individually. They also reduce operating costs in terms of fewer haul trucks and less personnel.
With a so-equipped mobile crusher, the feed operator can shut the machine down or change the size of the material, all using the remote control, or use it to walk the crusher from one part of the site to the other, or onto a flat bed trailer for relocation to a different quarry or recycling yard. This reduces personnel and hauling costs compared to a stationary plant. With the mobile jaw or impact primary crusher, the only additional personnel needed would be a skid-steer operator to remove scrap steel, and someone to move the stockpiles.
Thanks to better technology, mobile plants can achieve final aggregate fractions, which previously only were possible with stationary plants. Production availability is on par with stationary plants. Theyre applicable in all quarries, but can be used for small deposits if the owner has several quarries or various operation sites. For example, an operator of several stone quarries can use the plants in changing market situations at different excavation sites. In addition, they also can be used as individual machines. A further factor is that mobile plants, in general, require simpler and shorter licensing procedures.
The high cost of labor keeps going up. A stationary crusher might be able to produce multiple times the amount of product, but also would require about seven or eight workers. Aggregate producers can benefit when producing material with the minimized crew used for mobile jaw and impact crushers.
Using correct maintenance practices, mobile crushers will remain dependable throughout their working life. Crushing and processing material can result in excessive wear on certain components, excessive vibration throughout the plant, and excessive dust in the working environment. Some applications are more aggressive than others. A hard rock application is going to require more maintenance on top of standard maintenance, as there will be more vibration, more dust and more wear than from a softer aggregate.
Due to the nature of its purpose, from the moment a mobile crusher starts, the machine is wearing itself out and breaking itself down. Without routine, regular maintenance and repair, a mobile crusher will not be reliable nor provide the material customers demand.
The first area of wear on any machine is the feed system. Whether its a feeder with an integrated grizzly, or a feeder with an independent prescreen, how the machine is fed contributes to wear. When setting up and maintaining a machine, the machine must be level. A machine that is unlevel left to right will experience increased wear on all components, including the feeder, the screens, the crushing chambers and the conveyor belts. In addition, it reduces production and screening efficiency, as the whole area of the machine is not being effectively used. Also, having the machine sit high at the discharge end will have the effect of feeding the material uphill in the feeder and reducing its efficiency, thus reducing production.
Another area for consideration is the equipment used to feed the machine. The operator using a loader to feed the crusher will have no control over the feed size, as he cannot see whats in the bucket. Whereas with an excavator, the operator can see whats inside and has more control over the feed into the hopper. That is, the operator is not feeding so much material all at once and is controlling the size of the feed. This reduces wear in the feed hoppers impact zones and eliminates material blockages due to feed size being too large to enter the chamber.
Dust is a problem in its own right, especially for the power plant of the mobile crusher. In a very dusty application, it is easy to plug the radiator and have engine-overheating problems. High dust levels cause increased maintenance intervals on air filters, and if not controlled properly, can enter the diesel tank and cause problems with the fuel system. Also, dust that gets inside the crusher increases wear. But if systems are put in place to remove the dust, it should keep it from going into the machine in the first place.
Dust also is a hazard on walkways and a problem for conveyors. If maintained, side-skirting and sealing the conveyors keeps dust from spilling out, building up underneath the conveyor, or building up in rollers, pulleys, bearings, and causing wear on shafts. Its important to maintain the sealing rubbers on the conveyor belts to avoid those issues. Routine maintenance calls for removing accumulated dust from inside and under the machine.
Dust also is a problem for circuit boards and programmable controllers. Dust causes electrical switches to malfunction because it stops the contacts from correctly seating. Electrical systems under positive air pressure dont permit dust to penetrate the control system. In control panels with a correctly maintained positive pressure system, filters remove dust from air that is being pumped into the cabinets. If the filters are plugged, the system will not pull as much air through, allowing dust, moisture and heat to build in the cabinet.
There are also impact aprons against which the rock is thrown, which also see high wear. There are side plates or wear sheets on the sides of the machine. The highest wear area is around the impact crusher itself, around the circumference of the rotor. If not maintained, the wear items will wear through and compromise the structure of the crusher box.
Conduct a daily visual check of the machine. The jaw is simple; just stand up on the walkway and take a look down inside. A crushers jaw plate can be flipped so there are two sides of wear on them. Once half the jaw is worn out, flip it; once that side is worn, change it.
The impact crusher will have an inspection hatch to see inside. Check to see how much material is left on the blow bars and how much is left on the wear sheets on the side of the crusher box. If half the bar is worn out after one week, change the blow bars in another week.The frequency of changes depends entirely on the application and the rock that is being crushed.
They have to be user serviceable, user friendly, and able to be changed in a short time. The best way to change these parts is a service truck with a crane; some use excavators but thats not recommended by any means.
After initial blasting, breakers are used to break down aggregate that typically is not only too large to be hauled in dump trucks, but also too large for crushers that size rock to meet asphalt, drainage system, concrete and landscaping specifications. Breakers can be mounted to a mobile carrier, such as an excavator, or to stationary boom systems that can be attached to a crusher. The total number of hydraulic breakers can vary from site to site depending on production levels, the type of aggregate materials and the entire scope of the operation.
Without hydraulic breakers, workers rely on alternative practices that can quickly affect production rates. For instance, blasting mandates shutting down operations and moving workers to a safe location. And when you consider how many times oversize aggregate might need to be reduced, this can lead to a significant amount of downtime and substantially lower production rates.
Aggregate operations can use hydraulic breakers to attack oversize without having to clear the quarry. But with an ever-growing variety of manufacturers, sizes and models to choose from, narrowing the decision to one hydraulic breaker can be overwhelming with all of the stats and speculation. Thats why its important to know what factors to consider before investing in a new hydraulic breaker.
In most cases, heavy equipment dealers are very knowledgeable about quarry equipment, including breakers, so they are a good resource for finding the best model for a carrier, usually an excavator or stationary boom system. More than likely, they will have specifications and information about various breaker sizes to help gauge what model is best. But being familiar with what to look for in a breaker can streamline the selection process.
The best places to look for breaker information are in the manufacturers brochure, website, owners manual or catalogue. First, carefully review the carrier weight ranges. A breaker that is too big for the carrier can create unsafe working conditions and cause excessive wear to the carrier. An oversized breaker also transmits energy in two directions, toward the aggregate and through the equipment. This produces wasted energy and can damage the carrier. But using a breaker thats too small puts excessive force on the tool steel, which transmits percussive energy from the breaker to the material. Using breakers that are too small also can damage mounting adapters and internal components, which considerably decreases their life.
Once you find a breaker that meets the carriers capacity, check its output power, which is typically measured in foot-pounds. Foot-pound classes are generalizations and are not based on any physical test. Often the breakers output will be documented in one of two ways: as the manufacturers calculated foot-pound class or as an Association of Equipment Manufacturers measured foot-pound rating. Foot-pound class ratings can be deceiving since they are loosely based on the breakers service weight and not the result of any physical test. The AEM rating, on the other hand, measures the force a breaker exerts in a single blow through repeatable and certified testing methods. The AEM rating, which was developed by the Mounted Breaker Manufacturers Bureau, makes it easier to compare breaker models by reviewing true figures collected during an actual test procedure.
For instance, three breaker manufacturers might claim their breakers belong in a 1,000-lb. breaker class. But AEM testing standards could reveal all three actually have less foot-pound impact. You can tell if a breaker has been AEM tested if a manufacturer provides a disclosure statement or if the breaker is labeled with an AEM Tool Energy seal. If you cannot find this information, contact the manufacturer. In addition to output energy specifications, manufacturers often supply estimates for production rates on different types of aggregate material. Make sure to get the right measurements to make the best decision.
In addition to weight and output power, look at the breakers mounting package. Two things are crucial for mounting a breaker to a carrier: a hydraulic installation kit and mounting components. Breakers need hydraulic plumbing with unidirectional flow to move oil from the carrier to the breaker and back again. A one-way flow hydraulic kit is sufficient to power the breaker as long as the components are sized to properly handle the required flows and pressures. But, consider a bidirectional flow hydraulic kit if you plan to use the same carrier with other attachments that require two-way flow. Check with the dealer or breaker manufacturer to determine which hydraulic package best fits current and future needs.
Hydraulic flow and pressure specifications also need to be considered when pairing a breaker to a hydraulic system. If the carrier cannot provide enough flow at the right pressure, the breaker wont perform with maximum output, which lowers productivity and can damage the breaker. Additionally, a breaker receiving too much flow can wear quickly, which reduces its service life. For the best results, follow the hydraulic breaker specifications found in owners manuals, catalogs and brochures. Youll find out if a breaker has additional systems that might require additional servicing. For instance, some breakers feature nitrogen gas-assist systems that work with the hydraulic oil to accelerate the breakers piston. The nitrogen systems specifications need to be followed for consistent breaker power output.
Brackets or pin and bushing kits are commonly required to attach the breaker to the carrier. Typically they are bolted to the top of a breaker and are configured to match a specific carrier. Some manufacturers make universal mounting brackets that can accommodate two or three different sizes of carriers. With the adjustable pins, bushings or other components inside these universal brackets, the breaker can fit a range of carriers. However, varying distances between pin centers can complicate hookups to quick coupling systems. In addition, loose components, such as spacers, can become lost when the breaker is not in use and detached from the carrier.
Some carriers are equipped with quick-coupling systems, which require a breakers mounting interface to be configured like the carriers original attachment. Some manufacturers produce top-mount brackets that pair extremely well with couplers. This allows an operator to use the original bucket pins from the carrier to attach the breaker, and eliminates the need for new pins. This pairing also ensures a fast pickup with the quick coupler.
Its also a good idea to check which breaker tools are available through the dealer and manufacturer. The most common for aggregate mining are chisels and blunts. There are two kinds of chisels commonly used in aggregate mines: crosscut and inline. Both chisels resemble a flat head screwdriver, but the crosscut chisels are used when carrier operators want to direct force in a left-to-right concentration; whereas, inline chisels direct force fore and aft. With chisel tools, operators can concentrate a breakers energy to develop cracks, break open seams or define scribe lines.
If a chisel cant access or develop a crack or seam, a blunt can be used. Blunts have a flattened head that spreads the energy equally in all directions. This creates a shattering effect that promotes cracks and seam separation. Ask your dealer if the tools you are considering are suited for the application. Using non-original equipment manufacturer tool steel can damage the percussive piston in the breaker, seize into the wear bushings, or cause excessive wear.
Regular breaker maintenance is necessary, yet its one of the biggest challenges for aggregate operations. It not only extends the life of the breaker, but also can keep minor inconveniences from turning into expensive problems. Some manufacturers recommend operators inspect breakers daily to check grease levels and make sure there are no worn or damaged parts or hydraulic leaks.
Breakers need to be lubricated with adequate amounts of grease to keep the tool bushing area clear and reduce friction, but follow the manufacturers recommendations. For example, adding grease before properly positioning the breaker can lead to seal damage or even catastrophic failure. And too little grease could cause the bushings to overheat, seize and damage tools. Also, manufacturers advise using high-moly grease that withstands working temperatures greater than 500 degrees. Some breakers have automatic lube systems that manage grease levels, but those systems still need inspections to ensure there is adequate grease in their vessels. Shiny marks on the tool are a good indication the breaker is not properly lubricated.
Little has changed in basic crusher design over past decades, other than that of improvements in speed and chamber design. Rebuilding and keeping the same crusher in operation year after year has long been the typical approach. However, recent developments have brought about the advent of new hydraulic systems in modern crusher designs innovations stimulated by the need for greater productivity as well as a safer working environment. Importantly, the hydraulic systems in modern crusher designs are engineered to deliver greater plant uptime and eliminate the safety risks associated with manual intervention.
Indeed the crushing arena is a hazardous environment. Large material and debris can jam inside the crusher, damaging components and causing costly downtime. Importantly, manually digging out the crusher before repairs or restarts puts workers in extremely dangerous positions.
The Mine Safety and Health Administration has reported numerous injuries and fatalities incurred when climbing in or under the jaw to manually clear, repair or adjust the typical older-style jaw crusher. Consider that fatalities and injuries can occur even when the machine is locked out and tagged out. Recent examples include a foreman injured while attempting to dislodge a piece of steel caught in the primary jaw crusher. Another incident involved a fatality when a maintenance man was removing the toggle plate seat from the pitman on a jaw crusher. The worker was standing on a temporary platform when the bolts holding the toggle seat were removed, causing the pitman to move and strike him.
The hydraulic systems on modern crusher designs eliminate the need for workers to place themselves in or under the crusher. An overview of hydraulic system technology points to these three key elements:
A hydraulic chamber-clearing system that automatically opens the crusher to a safe position, allowing materials to pass. A hydraulic overload relief that protects parts and components against overload damage. A hydraulic adjustment that eliminates the maintenance downtime associated with manual crusher adjustments, and maintains safe, consistent crusher output without the need for worker intervention.
Whether a crusher is jammed by large material, tramp iron or uncrushable debris; or is stalled by a power failure the chamber must be cleared before restarting. Manual clearing is a lengthy and risky task, especially since material can be wedged inside the crusher with tremendous pressure, and dislodging poses much danger to workers placed in harms way inside the crusher.
Unlike that of the older-style jaw, the modern jaw will clear itself automatically with hydraulics that open the crusher to a safe position, and allow materials to pass again, without the need for manual intervention. If a feeder or deflector plate is installed under the crusher, uncrushable material will transfer smoothly onto the conveyor without slicing the belt.
To prevent crusher damage, downtime and difficult maintenance procedures, the hydraulic overload relief system opens the crusher when internal forces become too high, protecting the unit against costly component failure. After relief, the system automatically returns the crusher to the previous setting for continued crushing.
The modern crusher is engineered with oversized hydraulic cylinders and a traveling toggle beam to achieve reliable overload protection and simple crusher adjustment. All closed-side setting adjustments are made with push-button controls, with no shims being needed at any time (to shim is the act of inserting a timber or other materials under equipment). This is a key development as many accidents and injuries have occurred during shim adjustment, a process which has no less than 15 steps as described in the primary crusher shim adjustment training program offered by MSHA.
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Triple Roll Crushers. Triple Roll Crushers are ideal for producers who want to accomplish two stages of reduction in one pass. They can be used in coal, salt, coke, glass, and trona operations, among others. Triple Roll Crushers combine a Single Roll Crusher with a Double Roll Crusher to form a crusher that is capable of achieving a 6:1 reduction ratio in the primary stage and a 4:1 reduction ...
Brief Introduction of Roll Crusher. The roller crusher can be used to finely crush various high and medium hardness ores and rocks in industrial sectors such as mineral processing, chemical industry, cement, refractory materials, abrasives, and building materials, especially for the production of guar and mung bean sand in the building materials industry.
Monrovia Liberia Africa high quality large coal roll crusher price ... Ball mill introduction manufacturers manual pdf ball mill closed circuit closed circuit diagram for cement mill in rod mill an open circuit ball mill wikipedia the ball mill is a key piece of equipment for grinding crushed materials and it is widely used in production lines ...
Roll crusher is a crushing machine researched and manufactured by our company for coarse crushing. Impact Crusher An impact crusher is a piece of heavy construction equipment people can use to reduce the size of things like rock, waste concrete, and similar materials.
Progress in Roll-Crushing. BY C. Q. Payne, New York, N. Y. On the right, a Roll Crushers is shown in a sectional elevation of the A-C single-roll crusher while here below is a cutaway view of the machine, with hopper and part of the near side frame removed to show the crushing chamber. The moving elements of the machine consist of the roll, with its supporting shaft and driving gear, and the ...
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The roller crusher produced by our company includes the following series: single roll crusher and double roller crusher. Double roller crusher has a larger production capacity than that of single roll crusher. Final Output Size; About the final output size, the commonly seen output size types have 0-10mm, 10-20mm, 20-30mm, 30-40mm, etc.
Vertical Roller Mill Specifi Ions hetkrinkeltje be. Vertical roller mill wikipedia vertical roller mill is a type of grinder used to grind materials into extremely fine powder for use in mineral dressing processes, paints, pyrotechnics, cements and ceramics it is an energy efficient alternative for a ball mill overview vertical roller mill has many different forms, but it works basically
Feb 19, 2021 Roll crushers especially have larger capacity, higher reduction efficiency and more excellent processing performance for the brittle minerals under the compressive strength of 160 MPa.:::Single Roll Crushers The Single Roll Crusher, with its 6:1 ratio of reduction, is ideal for reducing large feed lumps to a medium product size while producing a considerably lower percentage Read
pasien merasa nyaman. Spesialis Urologi akan memasukkan pipa dengan kamera kecil di ujungnya melalui saluran kemih sampai ke ginjal. Saat batu ginjal terlihat, maka dokter akan menghancurkan batu tersebut dengan menggunakan energi laser (contoh: Laser Holmium) dan batu ginjal yang hancur akan diangkat. Seluruh prosedur dilakukan secara
Based on 30 years of development experience of grinding equipment, LM Heavy Industry produced LUM Series Superfine Vertical Roller Grinding Mill to make ultra-fine powder. The grinding roller doesn't contact with millstone usually, which makes abrasion little and service life longer.
We have toothed roll crusher machine ,402 double toothed roll crusher products are offered for sale by suppliers on Alibaba.com, of which crusher accounts for 94%, plastic crushing machines accounts for 3%. A wide variety of double toothed roll crusher options are available to you, such as 1 year, 2 years, and more than 5 years
pulverizer gearboxes. Most of these pulverizer gearboxes are still operating today. In 1973, we were the first to introduce the modular gearbox component design, allowing the gearbox to be removed without having to take apart the entire pulverizer. Timken has produced and supplied pulverizer gearboxes to most major pulverizer OEMs. Today, we have
V-Slam VSI Models from Stedman are vertical shaft impactors for all your coarse-to-fine crushing needs. VSI crushers offer significant savings over higher-priced competitive crushers. The V-Slam, with its low horsepower per ton of throughput, minimizes operating costs.
Our vertical shaft impactors featuremultiple rotor configurations for various applications. From open and enclosed rotors to the Stedman Patented Tubular Rotor, each machine is configured to provide customers exactly what is needed for their unique application.
The new Patented Tubular Rotor provides many benefits over the standard shoe and anvil designs as well as rock-shelf applications. The easily replaceable and indexable rotor tubes, cut your total operating cost and maintenance time in half, making V-Slam the easiest VSI crusher to maintain and one of the best impact crushers on the market.
Stedman's testing facilities provide real-world conditions to view your materials being processed. Test out a range of different size reduction methods, saving you both time and money when selecting the proper size reduction method.
Why Stedman? Delivering equipment and service you deserve For nearly two centuries, Stedman Machine Company has produced quality, reliable and durable size reduction and industrial crushing equipment. Stedman has expert field service and installation technicians ready to assist with all maintenance and equipment commissioning needs. Unsurpassed industry experience operating since 1834 State-of-the-art equipment testing facilities Dedicated, professional staff Parts and service available 24 hours a day
For nearly two centuries, Stedman Machine Company has produced quality, reliable and durable size reduction and industrial crushing equipment. Stedman has expert field service and installation technicians ready to assist with all maintenance and equipment commissioning needs.
Stedman Machine is a leading manufacturer of VSI crushers with the capability to provide customer service across the globe. Our experienced team will work with you to create the best impact crusher system to make your processes the most efficient. Call us for more information!
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Anticoi, H.; Guasch, E.; Ahmad Hamid, S.; Oliva, J.; Alfonso, P.; Bascompta, M.; Sanmiquel, L.; Escobet, T.; Escobet, A.; Parcerisa, D.; Pea-Pitarch, E.; Argelaguet, R.; De Felipe, J.J. An Improved High-Pressure Roll Crusher Model for Tungsten and Tantalum Ores. Minerals 2018, 8, 483. https://doi.org/10.3390/min8110483
Anticoi H, Guasch E, Ahmad Hamid S, Oliva J, Alfonso P, Bascompta M, Sanmiquel L, Escobet T, Escobet A, Parcerisa D, Pea-Pitarch E, Argelaguet R, De Felipe JJ. An Improved High-Pressure Roll Crusher Model for Tungsten and Tantalum Ores. Minerals. 2018; 8(11):483. https://doi.org/10.3390/min8110483
Anticoi, Hernan, Eduard Guasch, Sarbast Ahmad Hamid, Josep Oliva, Pura Alfonso, Marc Bascompta, Lluis Sanmiquel, Teresa Escobet, Antoni Escobet, David Parcerisa, Esteban Pea-Pitarch, Rosa Argelaguet, and Jose J. De Felipe 2018. "An Improved High-Pressure Roll Crusher Model for Tungsten and Tantalum Ores" Minerals 8, no. 11: 483. https://doi.org/10.3390/min8110483