double rotor hammer crusher

roll crusher manufacturer & design | williams crusher

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Williams is an industry-leading roll crusher manufacturer and designer for high-quality roll crushers with desirable benefits such as high throughput capacity, minimal maintenance requirements, low cost per ton operation, and more. Learn more about our heavy-duty roll crushers below or contact our sales engineers to talk about your application needs.

A combination of impact, shear, and compression are the forces necessary to perform the crushing and size reduction in a Williams roll crusher. The material enters the roll crusher machine and is impacted by the roll as it rotates. Then, as the material is pulled between a crushing plate or rolls, shear and compression forces act upon the material. The rolls act as flywheels, contributing to smooth operation and efficient use of power. Roll crushing surfaces operate at a fixed distance apart, as opposed to the continually changing distances in a jaw or cone crusher. This creates a more consistent product size.Roll crushers are low in profile and relatively easy to install. They can be fed with a minimum of headroom, or even choke fed. Adjustments are simple andinternal parts are readily accessible.

Typical feed materials for Williams Roll Crushers include: bauxite, cement clinker, chalk, cinders, clay, coal, glass, gypsum, limestone, burnt lime, rock salt, sandstone, shale, sulfur ore, sea shells, and sewer sludge clinker. Single Roll Crushers, sometimes called lump breakers, can also be used for breaking frozen or agglomerated materials.

Williams Roll Crushers are used in a variety of industries such as, mining recycling, and power industries. Interested in learning more about the Williams Roll Crushers for your specific industry and application? Contact our sales engineers!

Choosing between a single roll crusher and double roll crusher depends upon the type of feed material, feed size, product size desired, and consistency of both feed and product. Both single and double roll crushers operate most efficiently with dry, friable materials. However, single roll machines have been widely and successfully used for the reduction of moist clays. They also have been long used as primary and secondary coal crushers, both at mine sites and power plants, where a minimum of fines is desired.

Williams single roll crushers reduce via a combination of impact, shear, and compression. The rolls are always toothed in patterns suited to the feed material. Single Roll Crushers generally handle larger feed sizes at higher reduction ratios in higher capacities and are particularly well suited to be used as lump breakers.

Double roll crushers reduce primarily through compression, although some shear is obtained with toothed rolls. Rolls for these crushers come in combinations of smooth, corrugated, and toothed designs. Double Roll Crushers produce a finer product at lower reduction ratios and capacities.

Oversized, heat-treated, alloy steel shafts plus self-aligning, roller-type bearings assure long life and maximum use of power. Jackshafts for control of roller speed are standard on double roll crushers, optional on larger Single Roll Crushers.

Heavy-duty compression springs permit movement of floating roll to pass tramp metal and other uncrushables, avoiding overload and damage. Smaller Single Roll Crushers are equipped with a shear pin release.

Faces Tooth patterns and corrugations to fit feed material; abrasion-resistant alloy; easily replaceable. Ash Crushers have additional features including dust-tight design and sealed cover plates for breaker plate access.

Williams Single Roll Crushers are also available in a 15 inch (381mm) diameter dust-tight version for applications such where it would be expensive to have dust collection air. Already well known for rugged construction, low profile, high reduction ratio, and economical cost, Williams Dust-Tight Ash Single Roll Crushers also have easy access to the rotor for maintenance. These dust-tight roll crushers are perfect for applications such as crushing ash, limestone, coal, or glass.

types of crushers

Impact Crushers: This division is represented chiefly by the various styles of hammermill; also by the cage type disintegrator. Combination Impact and Sledging Crushers. In this class we have the single or double sledging roll crushers. An example of the former is the Fairmount crusher, of the latter, the Edison roll crusher.

Some further subdividing and qualification might be applied to these general classifications, but these, for the most part, are not of particular importance. Pressure crushers, for example, may be divided into two subclasses: the reciprocating, and the continuous-pressure, types. The gyratory and jaw crushers come under the first category, the crushing rolls under the second. Strictly speaking, the gyratory motion is not a reciprocating one, but it is so with respect to any vertical radial plane through the crushing chamber; therefore it is convenient to view it in that light. Some roll crushers, notably the light coal crushing type, have more of a tearing action, as contrasted to the heavy sledging performance of such machines as the Fairmount crusher.

During the same years wherein the industry was concerned with development of larger and still larger primary crushers,another member of the family was born: the single, sledging- roll crusher. The Allis-Chalmers Co. entered this field in 1911, building two sets of 36 dia. x 60 face single-roll crushers, flux limestone plant. Taking the name of its proving ground, this machine was christened the Fairmount crusher. The machine quickly achieved a high degree of popularity, and although its field of application is relatively limited, quite a number of them were in-stalled for primary crushing service. The line was expanded to include smaller sizes, as well as the big 60- x 84-in. machine.

Development of concentration and cyanidation in the mining industry called for finer crushing than was feasible in the gyratory or jaw crushers then available. This requirement was met for a number of years by the double smooth-face crushing rolls, originally known as Cornish rolls. As the mining industry during the period we are discussing was a very active one, the development in this type of crusher had reached a fairly high stage before the end of the century, and some excellent heavy-duty roils were available at that time. That this machine was not used to any considerable extent in the commercial crushing plants of that period was due simply to the fact that there was no demand for the smaller sizes of crushed stone, at least not any more than could be taken care of by the crushing methods then in vogue in such plants. This brings us to the rather significant fact that, while all of the interesting and rather remarkable development we have outlined was going on, very little, if anything, was being done to develop special crushers for secondary and fine-reduction work, other than the work on crushing rolls just described.

a jaw, b cone, c mushroom, d hammer, e roller; 1 fixed cheek with the rotation axis; 2 a movable cheek; 3, 4 the eccentric shaft; 5 rod; 6 hinged rear bearing spacer cheeks; 7 spring; 8, 9 width adjustment mechanism of the discharge gap; 10 pull the lock device; 11 bed; 12 still cone; 13 cone moving; 14 traverse; 15 hinge suspension rolling cone; 16 cone of the shaft; 17 drive shaft; 18 eccentric; 19 amortization spring; 20 foot ring ;21 regulating ring; 22 thrust bearing cone; 23 rotor; 24 liner plates; 25 grate; 26 hammer; 27 main frame; 28 crushing rolls.

gyratory crusher - an overview | sciencedirect topics

Gyratory crushers were invented by Charles Brown in 1877 and developed by Gates around 1881 and were referred to as a Gates crusher [1]. The smaller form is described as a cone crusher. The larger crushers are normally known as primary crushers as they are designed to receive run-on-mine (ROM) rocks directly from the mines. The gyratory crushers crush to reduce the size by a maximum of about one-tenth its size. Usually, metallurgical operations require greater size reduction; hence, the products from the primary crushers are conveyed to secondary or cone crushers where further reduction in size takes place. Here, the maximum reduction ratio is about 8:1. In some cases, installation of a tertiary crusher is required where the maximum reduction is about 10:1. The secondary crushers are also designed on the principle of gyratory crushing, but the construction details vary.

Similar to jaw crushers, the mechanism of size reduction in gyratory crushers is primarily by the compressive action of two pieces of steel against the rock. As the distance between the two plates decreases continuous size reduction takes place. Gyratory crushers tolerate a variety of shapes of feed particles, including slabby rock, which are not readily accepted in jaw crushers because of the shape of the feed opening.

The gyratory crusher shown in Figure 2.6 employs a crushing head, in the form of a truncated cone, mounted on a shaft, the upper end of which is held in a flexible bearing, whilst the lower end is driven eccentrically so as to describe a circle. The crushing action takes place round the whole of the cone and, since the maximum movement is at the bottom, the characteristics of the machine are similar to those of the Stag crusher. As the crusher is continuous in action, the fluctuations in the stresses are smaller than in jaw crushers and the power consumption is lower. This unit has a large capacity per unit area of grinding surface, particularly if it is used to produce a small size reduction. It does not, however, take such a large size of feed as a jaw crusher, although it gives a rather finer and more uniform product. Because the capital cost is high, the crusher is suitable only where large quantities of material are to be handled.

However, the gyratory crusher is sensitive to jamming if it is fed with a sticky or moist product loaded with fines. This inconvenience is less sensitive with a single-effect jaw crusher because mutual sliding of grinding surfaces promotes the release of a product that adheres to surfaces.

The profile of active surfaces could be curved and studied as a function of the product in a way to allow for work performed at a constant volume and, as a result, a higher reduction ratio that could reach 20. Inversely, at a given reduction ratio, effective streamlining could increase the capacity by 30%.

Maintenance of the wear components in both gyratory and cone crushers is one of the major operating costs. Wear monitoring is possible using a Faro Arm (Figure 6.10), which is a portable coordinate measurement machine. Ultrasonic profiling is also used. A more advanced system using a laser scanner tool to profile the mantle and concave produces a 3D image of the crushing chamber (Erikson, 2014). Some of the benefits of the liner profiling systems include: improved prediction of mantle and concave liner replacement; identifying asymmetric and high wear areas; measurement of open and closed side settings; and quantifying wear life with competing liner alloys.

Crushers are widely used as a primary stage to produce the particulate product finer than about 50100mm. They are classified as jaw, gyratory, and cone crushers based on compression, cutter mill based on shear, and hammer crusher based on impact.

A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake. A Fritsch jaw crusher with maximal feed size 95mm, final fineness (depends on gap setting) 0.315mm, and maximal continuous throughput 250Kg/h is shown in Fig. 2.8.

A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.

Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing hard metal scrap for different hard metal recycling processes. Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor. Crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough to pass through the openings of the grating or screen. The size of the product can be regulated by changing the spacing of the grate bars or the opening of the screen.

The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure, forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions. A design for a hammer crusher (Fig. 2.9) essentially allows a decrease of the elevated pressure of air in the crusher discharging unit [5]. The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, the circulation of suspended matter in the gas between A and B zones is established and the high pressure of air in the discharging unit of crusher is reduced.

Crushers are widely used as a primary stage to produce the particulate product finer than about 50100 mm in size. They are classified as jaw, gyratory and cone crushers based on compression, cutter mill based on shear and hammer crusher based on impact.

A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake.

A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.

Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing of hard metal scrap for different hard metal recycling processes.

Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor and crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough pass through the openings of the grating or screen. The size of product can be regulated by changing the spacing of the grate bars or the opening of the screen.

The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around of the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions.

A design for a hammer crusher (Figure 2.6) allows essentially a decrease of the elevated pressure of air in the crusher discharging unit [5]. The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, circulation of suspended matter in the gas between A- and B-zones is established and high pressure of air in the discharging unit of crusher is reduced.

Jaw crushers are mainly used as primary crushers to produce material that can be transported by belt conveyors to the next crushing stages. The crushing process takes place between a fixed jaw and a moving jaw. The moving jaw dies are mounted on a pitman that has a reciprocating motion. The jaw dies must be replaced regularly due to wear. Figure 8.1 shows two basic types of jaw crushers: single toggle and double toggle. In the single toggle jaw crusher, an eccentric shaft is installed on the top of the crusher. Shaft rotation causes, along with the toggle plate, a compressive action of the moving jaw. A double toggle crusher has, basically, two shafts and two toggle plates. The first shaft is a pivoting shaft on the top of the crusher, while the other is an eccentric shaft that drives both toggle plates. The moving jaw has a pure reciprocating motion toward the fixed jaw. The crushing force is doubled compared to single toggle crushers and it can crush very hard ores. The jaw crusher is reliable and robust and therefore quite popular in primary crushing plants. The capacity of jaw crushers is limited, so they are typically used for small or medium projects up to approximately 1600t/h. Vibrating screens are often placed ahead of the jaw crushers to remove undersize material, or scalp the feed, and thereby increase the capacity of the primary crushing operation.

Both cone and gyratory crushers, as shown in Figure 8.2, have an oscillating shaft. The material is crushed in a crushing cavity, between an external fixed element (bowl liner) and an internal moving element (mantle) mounted on the oscillating shaft assembly. An eccentric shaft rotated by a gear and pinion produces the oscillating movement of the main shaft. The eccentricity causes the cone head to oscillate between the open side setting (o.s.s.) and closed side setting (c.s.s.). In addition to c.s.s., eccentricity is one of the major factors that determine the capacity of gyratory and cone crushers. The fragmentation of the material results from the continuous compression that takes place between the mantle and bowl liners. An additional crushing effect occurs between the compressed particles, resulting in less wear of the liners. This is also called interparticle crushing. The gyratory crushers are equipped with a hydraulic setting adjustment system, which adjusts c.s.s. and thus affects product size distribution. Depending on cone type, the c.s.s. setting can be adjusted in two ways. The first way is by rotating the bowl against the threads so that the vertical position of the outer wear part (concave) is changed. One advantage of this adjustment type is that the liners wear more evenly. Another principle of setting adjustment is by lifting/lowering the main shaft. An advantage of this is that adjustment can be done continuously under load. To optimize operating costs and improve the product shape, as a rule of thumb, it is recommended that cones always be choke-fed, meaning that the cavity should be as full of rock material as possible. This can be easily achieved by using a stockpile or a silo to regulate the inevitable fluctuation of feed material flow. Level monitoring devices that detect the maximum and minimum levels of the material are used to start and stop the feed of material to the crusher as needed.

Primary gyratory crushers are used in the primary crushing stage. Compared to the cone type crusher, a gyratory crusher has a crushing chamber designed to accept feed material of a relatively large size in relation to the mantle diameter. The primary gyratory crusher offers high capacity thanks to its generously dimensioned circular discharge opening (which provides a much larger area than that of the jaw crusher) and the continuous operation principle (while the reciprocating motion of the jaw crusher produces a batch crushing action). The gyratory crusher has capacities starting from 1200 to above 5000t/h. To have a feed opening corresponding to that of a jaw crusher, the primary gyratory crusher must be much taller and heavier. Therefore, primary gyratories require quite a massive foundation.

The cone crusher is a modified gyratory crusher. The essential difference is that the shorter spindle of the cone crusher is not suspended, as in the gyratory, but is supported in a curved, universal bearing below the gyratory head or cone (Figure 8.2). Power is transmitted from the source to the countershaft to a V-belt or direct drive. The countershaft has a bevel pinion pressed and keyed to it and drives the gear on the eccentric assembly. The eccentric assembly has a tapered, offset bore and provides the means whereby the head and main shaft follow an eccentric path during each cycle of rotation. Cone crushers are used for intermediate and fine crushing after primary crushing. The key factor for the performance of a cone type secondary crusher is the profile of the crushing chamber or cavity. Therefore, there is normally a range of standard cavities available for each crusher, to allow selection of the appropriate cavity for the feed material in question.

Depending on the size of the debris, it may either be ready to enter the recycling process or need to be broken down to obtain a product with workable particle sizes, in which case hydraulic breakers mounted on tracked or wheeled excavators are used. In either case, manual sorting of large pieces of steel, wood, plastics and paper may be required, to minimise the degree of contamination of the final product.

The three types of crushers most commonly used for crushing CDW materials are the jaw crusher, the impact crusher and the gyratory crusher (Figure 4.4). A jaw crusher consists of two plates, with one oscillating back and forth against the other at a fixed angle (Figure 4.4(a)) and it is the most widely used in primary crushing stages (Behera etal., 2014). The jaw crusher can withstand large and hard-to-break pieces of reinforced concrete, which would probably cause the other crushing machines to break down. Therefore, the material is initially reduced in jaw crushers before going through any other crushing operation. The particle size reduction depends on the maximum and minimum size of the gap at the plates (Hansen, 2004).

An impact crusher breaks the CDW materials by striking them with a high-speed rotating impact, which imparts a shearing force on the debris (Figure 4.4(b)). Upon reaching the rotor, the debris is caught by steel teeth or hard blades attached to the rotor. These hurl the materials against the breaker plate, smashing them into smaller particle sizes. Impact crushers provide better grain-size distribution of RA for road construction purposes, and they are less sensitive to material that cannot be crushed, such as steel reinforcement.

Generally, jaw and impact crushers exhibit a large reduction factor, defined as the ratio of the particle size of the input to that of the output material. A jaw crusher crushes only a small proportion of the original aggregate particles but an impact crusher crushes mortar and aggregate particles alike and thus generates a higher amount of fine material (OMahony, 1990).

Gyratory crushers work on the same principle as cone crushers (Figure 4.4(c)). These have a gyratory motion driven by an eccentric wheel. These machines will not accept materials with a large particle size and therefore only jaw or impact crushers should be considered as primary crushers. Gyratory and cone crushers are likely to become jammed by fragments that are too large or too heavy. It is recommended that wood and steel be removed as much as possible before dumping CDW into these crushers. Gyratory and cone crushers have advantages such as relatively low energy consumption, a reasonable amount of control over the particle size of the material and production of low amounts of fine particles (Hansen, 2004).

For better control of the aggregate particle size distribution, it is recommended that the CDW should be processed in at least two crushing stages. First, the demolition methodologies used on-site should be able to reduce individual pieces of debris to a size that the primary crusher in the recycling plant can take. This size depends on the opening feed of the primary crusher, which is normally bigger for large stationary plants than for mobile plants. Therefore, the recycling of CDW materials requires careful planning and communication between all parties involved.

A large proportion of the product from the primary crusher can result in small granules with a particle size distribution that may not satisfy the requirements laid down by the customer after having gone through the other crushing stages. Therefore, it should be possible to adjust the opening feed size of the primary crusher, implying that the secondary crusher should have a relatively large capacity. This will allow maximisation of coarse RA production (e.g., the feed size of the primary crusher should be set to reduce material to the largest size that will fit the secondary crusher).

The choice of using multiple crushing stages mainly depends on the desired quality of the final product and the ratio of the amounts of coarse and fine fractions (Yanagi etal., 1998; Nagataki and Iida, 2001; Nagataki etal., 2004; Dosho etal., 1998; Gokce etal., 2011). When recycling concrete, a greater number of crushing processes produces a more spherical material with lower adhered mortar content (Pedro etal., 2015), thus providing a superior quality of material to work with (Lotfi etal., 2017). However, the use of several crushing stages has some negative consequences as well; in addition to costing more, the final product may contain a greater proportion of finer fractions, which may not always be a suitable material.

The first step of physical beneficiation is crushing and grinding the iron ore to its liberation size, the maximum size where individual particles of gangue are separated from the iron minerals. A flow sheet of a typical iron ore crushing and grinding circuit is shown in Figure 1.2.2 (based on Ref. [4]). This type of flow sheet is usually followed when the crude ore contains below 30% iron. The number of steps involved in crushing and grinding depends on various factors such as the hardness of the ore and the level of impurities present [5].

Jaw and gyratory crushers are used for initial size reduction to convert big rocks into small stones. This is generally followed by a cone crusher. A combination of rod mill and ball mills are then used if the ore must be ground below 325 mesh (45m). Instead of grinding the ore dry, slurry is used as feed for rod or ball mills, to avoid dusting. Oversize and undersize materials are separated using a screen; oversize material goes back for further grinding.

Typically, silica is the main gangue mineral that needs to be separated. Iron ore with high-silica content (more than about 2%) is not considered an acceptable feed for most DR processes. This is due to limitations not in the DR process itself, but the usual customer, an EAF steelmaking shop. EAFs are not designed to handle the large amounts of slag that result from using low-grade iron ores, which makes the BF a better choice in this situation. Besides silica, phosphorus, sulfur, and manganese are other impurities that are not desirable in the product and are removed from the crude ore, if economically and technically feasible.

Beneficiation of copper ores is done almost exclusively by selective froth flotation. Flotation entails first attaching fine copper mineral particles to bubbles rising through an orewater pulp and, second, collecting the copper minerals at the top of the pulp as a briefly stable mineralwaterair froth. Noncopper minerals do not attach to the rising bubbles; they are discarded as tailings. The selectivity of the process is controlled by chemical reagents added to the pulp. The process is continuous and it is done on a large scale103 to 105 tonnes of ore feed per day.

Beneficiation is begun with crushing and wet-grinding the ore to typically 10100m. This ensures that the copper mineral grains are for the most part liberated from the worthless minerals. This comminution is carried out with gyratory crushers and rotary grinding mills. The grinding is usually done with hard ore pieces or hard steel balls, sometimes both. The product of crushing and grinding is a waterparticle pulp, comprising 35% solids.

Flotation is done immediately after grindingin fact, some flotation reagents are added to the grinding mills to ensure good mixing and a lengthy conditioning period. The flotation is done in large (10100m3) cells whose principal functions are to provide: clouds of air bubbles to which the copper minerals of the pulp attach; a means of overflowing the resulting bubblecopper mineral froth; and a means of underflowing the unfloated material into the next cell or to the waste tailings area.

Selective attachment of the copper minerals to the rising air bubbles is obtained by coating the particles with a monolayer of collector molecules. These molecules usually have a sulfur atom at one end and a hydrophobic hydrocarbon tail at the other (e.g., potassium amyl xanthate). Other important reagents are: (i) frothers (usually long-chain alcohols) which give a strong but temporary froth; and (ii) depressants (e.g., CaO, NaCN), which prevent noncopper minerals from floating.

considering manufactured sand rock products magazine

Natural sand was produced by glaciers grinding bedrock under a heavy burden of ice over millions of years of time. This sand is most often found in and around rivers and streams.Sand on ocean beaches is contaminated with salt from the sea and sand from the desert is the wrong size to be used for concrete or asphalt.

Sand extraction and usage is now more than 50 billion tons per year. Sand and gravel, and concrete associations from all over the world are reporting signs of shortages of sand for concrete now and it will only get worse in the future. The United States, Canada, Australia. England, Europe, China and many other countries are hauling sand long distances to meet their concrete needs, and the balance of rock and sand for their concrete mixes.

Concrete mix designs have about 1.6 tons of aggregate per cu. yd. of concrete. Mix designs very from 40% to 45% sand and many pump mixes use up to 50% sand. The average sand use is about .75 tons (1.5 tons x .45) per cu. yd. of concrete. It is important to note that even if the sand meets the ASTM specification it needs also to have a Fineness Modulus (FM) of 2.5 to 3.00.

By-Product Sand, Crusher Dust, Crushed Rock FinesThe by-product sand produced when crushing large rock of 6-in. plus using a jaw crusher or horizontal shaft impact crusher as a primary crusher; or cone crushers used to crush rock from 6- to 1-in. can be classified to meet the C-33 sand specification but the shape will have a large percentage of flat and elongated material.

When tested with ASTM C1252 will have a high voids numbers of 46 plus, indicating a high percentage of flat and elongated material. In cases where the crusher fines are mixed with natural fines the ratio is normally 70% natural fines and 30% crusher fines the product can be used as concrete sand with little negative effect. This material can be used as asphalt sand as is. In a quarry application where there is no natural sand, it would not be suitable as concrete sand because of poor particle shape.

You can, however, run this material through a vertical shaft impact crusher with rotor and rock box to improve the particle shape and then classify to the C-33 specification and use it as manufactured sand.

Manufactured Concrete SandManufactured sand needs to be capable of replacing natural sand in concrete without any negative side effects. Two of the most common negative complaints are too high of FM and excessive flat and elongated material in the finished product.

For most materials that means re-crushing part of the #4 by #8 material or wasting it. The first step in the production of manufactured sand is crushing the rock to a gradation that when classified, by only removing the excess material passing the #100 and #200 sieve, will meet the C-33 Sand Specification on all the other sieves (#4, #8, #16, #30 and #50).

Normal manufactured sand will result in sand with less then 80% passing the #8 sieve before classification and 70% to 75% after classification (less than the 80% to 100%) required by the specification. This also results in a higher than 3.00 FM, one of the less than desirable manufactured sand conditions.

When using a compression type crusher like the cone crusher or high-pressure grinding role crusher (HPGR), the crushing is autogenous type which is rock on rock crushing. In autogenous crushing of the cone or HPGR the crusher receives the new feed plus the recirculating load with 75% to 100% less than the crusher closed side setting. This forces the crushing action to be many layers of rock to rock with inter particle cummunition. This produces a product with good quality shape.

Sand Production Crusher Wear CostThe chemical analysis and the paddle abrasion test can be used to help predict the wear cost of the crusher used. By finding the chemical content of the calcium carbonate (CaCo3), silicon dioxide (SiO2), iron oxide (Fe2O3), aluminum oxide (Al2O3) and magnesium carbonate (CaCO3) with this information you can establish a Silica Equivalent number.

More accurate results of the Paddle Abrasion test can be found by running a test. A vertical shaft with a paddle of known weight is rotated through a metal pan holding 400 grams of rock -in. x -in. The paddle is run for 15 minutes and 4 separate tests are run with 4 separate paddles. By measuring the wight loss of the paddle you use a wear chart to establish an Abrasion Index number.

High wear cost is not the problem if you can incorporate the cost into the selling price of the material. As sand becomes in shorter supply the price will increase making more possible to manufacture man sand o replace natural sand. What can be a problem is not knowing the wear cost beforehand.

ASTM C1252 Particle Shape testThe ASTM 1252 voids test uses a relationship of measured voids in non-compacted sand and the particle shape. The test consists of putting a dried sand sample into a container of known volume and compares the calculated weight of the material using the specific gravity of the sand sample to the measured weight in the test.

Natural sand with a result of 35% to 45% voids are considered acceptable for concrete sand. Sand with results of 45% to more than 50% are acceptable for asphalt mixes. Natural sand with no crushed sand particles added will give results of 35% to 40% and manufactured-sand with crushed material produced by a compression crusher in autogenous crushing (The feed material, new feed plus recirculating load, is smaller than the crusher closed side setting) will produce a sand product with 40% to 45% voids.

New Zealand and ASTM C939 flow cone tests can also be used to measure the particle shape of sands. The more alluvial the material with fewer square corners the faster the material will flow through a funnel with fixed opening.

By product sand can be used as concrete sand if you pass this material through a VSI rotor and rock box as a shaping operation. It would be best to send a sample of your material and see if a single pass in open circuit will improve the ASTM C1252 test results enough to consistently give you acceptable results.

International Manufactured Sand SpecificationIn most countries outside the United States, the use of manufactured sand is more common and a specification has been adopted that allows for more passing the #50, #100 and #200 sieves in the specification. This change in gradation will also lower the FM by .15 in most cases and reduces the amount of plus #8 that needs to be recruited to keep the gradation greater than 80% passing the #8 sieve.

For most of the concrete work that is performed for federal- and state-regulated projects the manufactured sand would have to be classified to the C-33 specification. The mix could consist of 50% manufactured sand and 50% natural sand if particle shape requires it, but the classified manufactured sand can meet all the requirements of the C-33 specification.

A separate set of mix designs could be developed that would include the use of the international manufactured sand specification by reducing the minus 200 mesh to less than 10% with air classification.

ConclusionIf you find that you are hauling sand from long distances to satisfy demand or the haul cost approaches the FOB price at your quarry or pit, you are running short of sand. To test your ability to manufacture sand for concrete with your material, first test your existing crusher discharge material and determine the signature of your rock.

Unlike normal crushing where the feed material is greater in size than the crusher setting, the crusher discharge gradation will change with the setting. The sand gradation, #4 x 0 will increase in percentage of the crusher discharge but the sand gradation between #4 and 0 will remain about the same.

No two sources will produce the same gradation and sometimes different elevations in your quarry may produce different results. Manufactured sand (#4 x 0) tends to produce a coarser sand with a high percentage of #4 x #8 material. This is the most difficult size to crush and in most cases the crusher discharge will contain 25% to 35% of #4 x #8 fraction when crushed to #4 x 0 product.

To produce a finished product that meets the C-33 specification, 80% to 10% passing the #8 sieve, the excess #4 x #8 material needs to be either rejected or sent back for re-crushing into the recirculating load.

The goal is to produce a finished product with a target gradation of dry crushed sand that will allow you to only have to remove the excess #100 and #200 material during classification to meet the product specification.

The classified sand should meet the concrete sand specification and keep the FM under 3.00. Sand with a FM of plus 3.00 is too coarse and leads to problems with finish ability, segregation of the mortar and the workability of the plastic concrete.

Next, you must decide what material size and gradation you plan on feeding the crusher to produce the manufactured sand. It is best to crush some of your material through a pilot plant that you can run for two or three months to establish the gradations, production rate and wear cost before you invest in larger size equipment at higher production rates.

You may also wish to rent a portable plant that can be set up at the plant site and try different crusher types. These might include a cone crusher, HPGR, VSI rotor and rock box and VSI rotor and anvil, hammer mill or double reversing cage mill.

Try different gradations of material and material that may be in excess inventory. It is not sufficient to crush your sand to minus #4. You need to re-crush the excess amount of #4 x #8 that is typically made (normally 3%) and the specification only allows 15% to 20%. Many concrete producers have used manufactured sand in the past and have had bad experiences because the sand they were furnished had a combination of poor particle shape, coarse gradation and FM above 3.0 to 3.5.

The second article in this series will introduce the advantages and disadvantages of using different crusher types to produce the manufactured sand. The third will address classification of the dry manufactured sand, with air, water, and treatment of the wastewater.

John Googins applications engineer crushing, screening and mineral processing is with Aggregate & Mining Consultants LLC, Littleton, Colo., www.miningconsultingusa.com. He can be reached at 303-547-0084 or [emailprotected].

cone crusher - an overview | sciencedirect topics

Cone crushers were originally designed and developed by Symons around 1920 and therefore are often described as Symons cone crushers. As the mechanisms of crushing in these crushers are similar to gyratory crushers their designs are similar, but in this case the spindle is supported at the bottom of the gyrating cone instead of being suspended as in larger gyratory crushers. Figure5.3 is a schematic diagram of a cone crusher.

The breaking head gyrates inside an inverted truncated cone. These crushers are designed so that the head-to-depth ratio is larger than the standard gyratory crusher and the cone angles are much flatter and the slope of the mantle and the concaves are parallel to each other. The flatter cone angles help to retain the particles longer between the crushing surfaces and therefore produce much finer particles. To prevent damage to the crushing surfaces, the concave or shell of the crushers is held in place by strong springs or hydraulics which yield to permit uncrushable tramp material to pass through.

The secondary crushers are designated as Standard cone crushers having stepped liners and tertiary Short Head cone crushers, which have smoother crushing faces and steeper cone angles of the breaking head. The approximate distance of the annular space at the discharge end designates the size of the cone crushers. A brief summary of the design characteristics is given in Table5.4 for crusher operation in open-circuit and closed-circuit situations.

The Standard cone crushers are for normal use. The Short Head cone crushers are designed for tertiary or quaternary crushing where finer product is required. These crushers are invariably operated in closed circuit. The final product sizes are fine, medium or coarse depending on the closed set spacing, the configuration of the crushing chamber and classifier performance, which is always installed in parallel.

For finer product sizes, i.e., less than 6mm, special cone crushers known as Gyradisc crushers are available. The operation is similar to the standard cone crushers, except that the size reduction is caused more by attrition than by impact [5]. The reduction ratio is around 8:1 and as the product size is relatively small the feed size is limited to less than 50mm with a nip angle between 25 and 30. The Gyradisc crushers have head diameters from around 900 to 2100mm. These crushers are always operated under choke feed conditions. The feed size is less than 50mm and therefore the product size is usually less than 69mm.

Maintenance of the wear components in both gyratory and cone crushers is one of the major operating costs. Wear monitoring is possible using a Faro Arm (Figure 6.10), which is a portable coordinate measurement machine. Ultrasonic profiling is also used. A more advanced system using a laser scanner tool to profile the mantle and concave produces a 3D image of the crushing chamber (Erikson, 2014). Some of the benefits of the liner profiling systems include: improved prediction of mantle and concave liner replacement; identifying asymmetric and high wear areas; measurement of open and closed side settings; and quantifying wear life with competing liner alloys.

Various types of rock fracture occur at different loading rates. For example, rock destruction by a boring machine, a jaw or cone crusher, and a grinding roll machine are within the extent of low loading rates, often called quasistatic loading condition. On the contrary, rock fracture in percussive drilling and blasting happens under high loading rates, usually named dynamic loading condition. This chapter presents loading rate effects on rock strengths, rock fracture toughness, rock fragmentation, energy partitioning, and energy efficiency. Finally, some of engineering applications of loading rate effects are discussed.

In Chapter4, we have already seen the mechanism of crushing in a jaw crusher. Considering it further we can see that when a single particle, marked 1 in Figure11.5a, is nipped between the jaws of a jaw crusher the particle breaks producing fragments, marked 2 and 3 in Figure11.5b. Particles marked 2 are larger than the open set on the crusher and are retained for crushing on the next cycle. Particles of size 3, smaller than the open set of the crusher, can travel down faster and occupy or pass through the lower portion of the crusher while the jaw swings away. In the next cycle the probability of the larger particles (size 2) breaking is greater than the smaller sized particle 3. In the following cycle, therefore, particle size 2 is likely to disappear preferentially and the progeny joins the rest of thesmaller size particles indicated as 3 in Figure11.5c. In the figures, the position of the crushed particles that do not exist after comminution is shaded white (merely to indicate the positions they had occupied before comminution). Particles that have been crushed and travelled down are shown in grey. The figure clearly illustrates the mechanism of crushing and the classification that takes place within the breaking zone during the process, as also illustrated in Figure11.4. This type of breakage process occurs within a jaw crusher, gyratory crusher, roll crusher and rod mills. Equation (11.19) then is a description of the crusher model.

In practice however, instead of a single particle, the feed consists of a combination of particles present in several size fractions. The probability of breakage of some relatively larger sized particles in preference to smaller particles has already been mentioned. For completeness, the curve for the probability of breakage of different particle sizes is again shown in Figure11.6. It can be seen that for particle sizes ranging between 0 K1, the probability of breakage is zero as the particles are too small. Sizes between K1 and K2 are assumed to break according a parabolic curve. Particle sizes greater than K2 would always be broken. According to Whiten [16], this classification function Ci, representing the probability of a particle of size di entering the breakage stage of the crusher, may be expressed as

The classification function can be readily expressed as a lower triangular matrix [1,16] where the elements represent the proportion of particles in each size interval that would break. To construct a mathematical model to relate product and feed sizes where the crusher feed contains a proportion of particles which are smaller than the closed set and hence will pass through the crusher with little or no breakage, Whiten [16] advocated a crusher model as shown in Figure11.7.

The considerations in Figure11.7 are similar to the general model for size reduction illustrated in Figure11.4 except in this case the feed is initially directed to a classifier, which eliminates particle sizes less than K1. The coarse classifier product then enters the crushing zone. Thus, only the crushable larger size material enters the crusher zone. The crusher product iscombined with the main feed and the process repeated. The undersize from the classifier is the product.

While considering the above aspects of a model of crushers, it is important to remember that the size reduction process in commercial operations is continuous over long periods of time. In actual practice, therefore, the same operation is repeated over long periods, so the general expression for product size must take this factor into account. Hence, a parameter v is introduced to represent the number of cycles of operation. As all cycles are assumed identical the general model given in Equation (11.31) should, therefore, be modified as

Multiple vectors B C written in matrix form:BC=0.580000.200.60000.120.180.6100.040.090.20.571.000000.700000.4500000=0581+00+00+000.580+00.7+00+000580+00+00.45+000.580+00+00+000.21+0.60+00+000.20+0.60.7+00+000.20+0.60+00.45+000.20+0.60+00+000.121+0.180+0.610+000.120+0.180.7+0.610+000.120+0.180+0.610.45+000.120+0.180+0.610+000.041+0.090+0.20+0.5700.040+0.090.7+0.20+0.5700.040+0.090+0.20.45+0.5700.040+0.090+0.20+0.570=0.580000.20.42000.120.1260.274500.040.0630.090

Now determine (I B C) and (I C)(IBC)=10.5800000000.210.42000000.1200.12610.27450000.0400.06300.0910=0.420000.20.58000.120.1260.725500.040.0630.091and(IC)=000000.300000.5500001

Now find the values of x1, x2, x3 and x4 as(0.42x1)+(0x2)+(0x3)+(0x4)=10,thereforex1=23.8(0.2x1)+(0.58x2)+(0x3)+(0x4)=33,thereforex2=65.1(0.12x1)+(0.126x2)+(0.7255x3)+(0x4)=32,thereforex3=59.4(0.04x1)+(0.063x2)+(0.09x3)+(1x4)=20,thereforex4=30.4

In this process, mined quartz is crushed into pieces using crushing/smashing equipment. Generally, the quartz smashing plant comprises a jaw smasher, a cone crusher, an impact smasher, a vibrating feeder, a vibrating screen, and a belt conveyor. The vibrating feeder feeds materials to the jaw crusher for essential crushing. At that point, the yielding material from the jaw crusher is moved to a cone crusher for optional crushing, and afterward to effect for the third time crushing. As part of next process, the squashed quartz is moved to a vibrating screen for sieving to various sizes.

Crushers are widely used as a primary stage to produce the particulate product finer than about 50100mm. They are classified as jaw, gyratory, and cone crushers based on compression, cutter mill based on shear, and hammer crusher based on impact.

A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake. A Fritsch jaw crusher with maximal feed size 95mm, final fineness (depends on gap setting) 0.315mm, and maximal continuous throughput 250Kg/h is shown in Fig. 2.8.

A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.

Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing hard metal scrap for different hard metal recycling processes. Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor. Crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough to pass through the openings of the grating or screen. The size of the product can be regulated by changing the spacing of the grate bars or the opening of the screen.

The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure, forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions. A design for a hammer crusher (Fig. 2.9) essentially allows a decrease of the elevated pressure of air in the crusher discharging unit [5]. The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, the circulation of suspended matter in the gas between A and B zones is established and the high pressure of air in the discharging unit of crusher is reduced.

Crushers are widely used as a primary stage to produce the particulate product finer than about 50100 mm in size. They are classified as jaw, gyratory and cone crushers based on compression, cutter mill based on shear and hammer crusher based on impact.

A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake.

A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.

Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing of hard metal scrap for different hard metal recycling processes.

Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor and crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough pass through the openings of the grating or screen. The size of product can be regulated by changing the spacing of the grate bars or the opening of the screen.

The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around of the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions.

A design for a hammer crusher (Figure 2.6) allows essentially a decrease of the elevated pressure of air in the crusher discharging unit [5]. The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, circulation of suspended matter in the gas between A- and B-zones is established and high pressure of air in the discharging unit of crusher is reduced.

For a particular operation where the ore size is known, it is necessary to estimate the diameter of rolls required for a specific degree of size reduction. To estimate the roll diameter, it is convenient to assume that the particle to be crushed is spherical and roll surfaces are smooth. Figure6.2 shows a spherical particle about to enter the crushing zone of a roll crusher and is about to be nipped. For rolls that have equal radius and length, tangents drawn at the point of contact of the particle and the two rolls meet to form the nip angle (2). From simple geometry it can be seen that for a particle of size d, nipped between two rolls of radius R:

Equation (6.2) indicates that to estimate the radius R of the roll, the nip angle is required. The nip angle on its part will depend on the coefficient of friction, , between the roll surface and the particle surface. To estimate the coefficient of friction, consider a compressive force, F, exerted by the rolls on the particle just prior to crushing, operating normal to the roll surface, at the point of contact, and the frictional force between the roll and particle acting along a tangent to the roll surface at the point of contact. The frictional force is a function of the compressive force F and is given by the expression, F. If we consider the vertical components of these forces, and neglect the force due to gravity, then it can be seen that at the point of contact (Figure6.2) for the particle to be just nipped by the rolls, the equilibrium conditions apply where

As the friction coefficient is roughly between 0.20 and 0.30, the nip angle has a value of about 1117. However, when the rolls are in motion the friction characteristics between the ore particle will depend on the speed of the rolls. According to Wills [6], the speed is related to the kinetic coefficient of friction of the revolving rolls, K, by the relation

Equation (6.4) shows that the K values decrease slightly with increasing speed. For speed changes between 150 and 200rpm and ranging from 0.2 to 0.3, the value of K changes between 0.037 and 0.056. Equation (6.2) can be used to select the size of roll crushers for specific requirements. For nip angles between 11 and 17, Figure6.3 indicates the roll sizes calculated for different maximum feed sizes for a set of 12.5mm.

The maximum particle size of a limestone sample received from a cone crusher was 2.5cm. It was required to further crush it down to 0.5cm in a roll crusher with smooth rolls. The friction coefficient between steel and particles was 0.25, if the rolls were set at 6.3mm and both revolved to crush, estimate the diameter of the rolls.

It is generally observed that rolls can accept particles sizes larger than the calculated diameters and larger nip angles when the rate of entry of feed in crushing zone is comparable with the speed of rotation of the rolls.

Jaw crushers are mainly used as primary crushers to produce material that can be transported by belt conveyors to the next crushing stages. The crushing process takes place between a fixed jaw and a moving jaw. The moving jaw dies are mounted on a pitman that has a reciprocating motion. The jaw dies must be replaced regularly due to wear. Figure 8.1 shows two basic types of jaw crushers: single toggle and double toggle. In the single toggle jaw crusher, an eccentric shaft is installed on the top of the crusher. Shaft rotation causes, along with the toggle plate, a compressive action of the moving jaw. A double toggle crusher has, basically, two shafts and two toggle plates. The first shaft is a pivoting shaft on the top of the crusher, while the other is an eccentric shaft that drives both toggle plates. The moving jaw has a pure reciprocating motion toward the fixed jaw. The crushing force is doubled compared to single toggle crushers and it can crush very hard ores. The jaw crusher is reliable and robust and therefore quite popular in primary crushing plants. The capacity of jaw crushers is limited, so they are typically used for small or medium projects up to approximately 1600t/h. Vibrating screens are often placed ahead of the jaw crushers to remove undersize material, or scalp the feed, and thereby increase the capacity of the primary crushing operation.

Both cone and gyratory crushers, as shown in Figure 8.2, have an oscillating shaft. The material is crushed in a crushing cavity, between an external fixed element (bowl liner) and an internal moving element (mantle) mounted on the oscillating shaft assembly. An eccentric shaft rotated by a gear and pinion produces the oscillating movement of the main shaft. The eccentricity causes the cone head to oscillate between the open side setting (o.s.s.) and closed side setting (c.s.s.). In addition to c.s.s., eccentricity is one of the major factors that determine the capacity of gyratory and cone crushers. The fragmentation of the material results from the continuous compression that takes place between the mantle and bowl liners. An additional crushing effect occurs between the compressed particles, resulting in less wear of the liners. This is also called interparticle crushing. The gyratory crushers are equipped with a hydraulic setting adjustment system, which adjusts c.s.s. and thus affects product size distribution. Depending on cone type, the c.s.s. setting can be adjusted in two ways. The first way is by rotating the bowl against the threads so that the vertical position of the outer wear part (concave) is changed. One advantage of this adjustment type is that the liners wear more evenly. Another principle of setting adjustment is by lifting/lowering the main shaft. An advantage of this is that adjustment can be done continuously under load. To optimize operating costs and improve the product shape, as a rule of thumb, it is recommended that cones always be choke-fed, meaning that the cavity should be as full of rock material as possible. This can be easily achieved by using a stockpile or a silo to regulate the inevitable fluctuation of feed material flow. Level monitoring devices that detect the maximum and minimum levels of the material are used to start and stop the feed of material to the crusher as needed.

Primary gyratory crushers are used in the primary crushing stage. Compared to the cone type crusher, a gyratory crusher has a crushing chamber designed to accept feed material of a relatively large size in relation to the mantle diameter. The primary gyratory crusher offers high capacity thanks to its generously dimensioned circular discharge opening (which provides a much larger area than that of the jaw crusher) and the continuous operation principle (while the reciprocating motion of the jaw crusher produces a batch crushing action). The gyratory crusher has capacities starting from 1200 to above 5000t/h. To have a feed opening corresponding to that of a jaw crusher, the primary gyratory crusher must be much taller and heavier. Therefore, primary gyratories require quite a massive foundation.

The cone crusher is a modified gyratory crusher. The essential difference is that the shorter spindle of the cone crusher is not suspended, as in the gyratory, but is supported in a curved, universal bearing below the gyratory head or cone (Figure 8.2). Power is transmitted from the source to the countershaft to a V-belt or direct drive. The countershaft has a bevel pinion pressed and keyed to it and drives the gear on the eccentric assembly. The eccentric assembly has a tapered, offset bore and provides the means whereby the head and main shaft follow an eccentric path during each cycle of rotation. Cone crushers are used for intermediate and fine crushing after primary crushing. The key factor for the performance of a cone type secondary crusher is the profile of the crushing chamber or cavity. Therefore, there is normally a range of standard cavities available for each crusher, to allow selection of the appropriate cavity for the feed material in question.

The main task of renovation construction waste handling is the separation of lightweight impurities and construction waste. The rolling crusher with opposite rollers is capable of crushing the brittle debris and compressing the lightweight materials by the low-speed and high-pressure extrusion of the two opposite rollers. As the gap between the opposite rollers, rotation speed, and pressure are all adjustable, materials of different scales in renovation construction waste can be handled.

The concrete C&D waste recycling process of impact crusher+cone crusher+hoop-roller grinder is also capable of handling brick waste. In general, the secondary crushing using the cone crusher in this process with an enclosed crusher is a process of multicrushing, and the water content of waste will become an important affecting factor. The wet waste will be adhered on the wall of the grinding chamber, and the crushing efficiency and waste discharging will be affected. When the climate is humid, only coarse impact crushing is performed and in this case the crushed materials are used for roadbase materials. Otherwise, three consecutive crushings are performed and the recycled coarse aggregate, fine aggregate, and powder materials are collected, respectively.

The brick and concrete C&D waste recycling process of impact crusher+rolling crusher+hoop-roller grinder is also capable of handling the concrete waste. In this case, the water content of waste will not be an important affecting factor. This process is suitable in the regions with wet climates.

The renovation C&D waste recycling process of rolling crusher (coarse/primary crushing)+rolling crusher (intermediate/secondary crushing)+rolling crusher (fine/tertiary crushing) is also capable of handling the two kinds of waste discussed earlier. The particle size of debris is crushed less than 20mm and the lightweight materials are compressed, and they are separated using the drum sieve. The energy consumption is low in this process; however, the shape of products is not good (usually flat and with cracks). There is no problem in roadbase material and raw materials of prefabricated product production. But molders (the rotation of rotors in crusher is used to polish the edge and corner) should be used for premixed concrete and mortar production.

181 process flow diagram (pfd) symbols for engineers | vista projects

Centrifuges are devices that use centrifugal force/ acceleration to separate components of a mixture on the bases of their density, size, viscosity, and rotor speed. The more dense molecules move to the outside of the centrifuge and the less dense molecules move towards the centre.

A process flow diagram is a flowchart that depicts the relationships between major components in a process or circuit. The concept originated in 1921 - it was designed by industrial engineer Frank Gilbreth. Today the concept is often used in industrial plants for chemical and process engineering but the concepts can also be applied to a number of other applications.

Process flow diagrams consist of a series of flowchart symbols and notations to illustrate a process. The different types of flowcharts can vary hugely from hand-drawn flowcharts to complex software flowcharts.

Process symbols represent an action, process, or function. They are also referred to as an 'action symbol' and are the most commonly used symbols in flowcharting. These types of symbols are often used in software.

hammer mills for material reduction | williams patent crusher

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Williams Patent Crusher is a leading industrial hammer mill manufacturer. Our industrial size reduction machines can handle any material size reduction job. Choose a Williams machine for high efficiency and economy. Using midair and impact crushing, grinding, and shredding, our machines can handle virtually any material.

A hammer mill is a particle size reduction machine. These machines grind and crush material using continual, high-speed hammer blows. This internal hammer shatters and disintegrates the material. Mills can be primary, secondary, or tertiary crushers, allowing for a wide variety of applications.

Williams hammer mills are a popular choice when it comes to particle size reduction. While many use these machines as rock crushers and stone crushers, they offer more versatility. Some of the industries and applications that benefit from this machine are:

Williams has been designing and manufacturing industry-leading hammer mills since 1871. We continue to innovate to exceed the evolving needs of our customers worldwide. Our vision is to recognize changes in the marketplace and provide a quality product. With Williams, you receive a quality product that always delivers the efficiency and ruggedness you expect.

Williams manufactures rugged hammer mills to handle high-tonnage size reduction jobs. This heavy-duty equipment reduces large materials, such as automobile bodies. More applications include rock and coal crushing, reducing limestone to sand and pulverizing metal turnings. They can also shred waste, wood, and paper for baling or burning.

The Williams Rocket Hammer Mill rapidly reduces non-abrasive materials to particle sized pieces. Applications include turning materials into fine granules. These materials include cereal, animal by-products, sawdust, expeller cake, rags, and wood pulp.

Meteor hammer mills use a high hammer-tip speed to produce a finer product. If your finished product needs to have specific characteristics, this is the ideal hammer mill. It is well suited for producing high-quality fluff for the absorbent and non-woven fiber markets.

The Type GP Hammer Mill is a simple, rugged machine for small and medium capacity particle size reduction jobs. It's used for a variety of applications from coal to limestone to salt cake, sawdust, and woodchips. It is a versatile machine that performs efficient particle size reduction. The Type GP also has customization options to meet your specific application needs.

Williams Ring Crushers are also known as turnings crushers. They reduce the size of metal turnings, bullshellings, or clips through impact crushing. Ring crushers produce their rated capacities with little down time and custom capabilities. This customization allows you to meet the exact specifications for your material reduction application.

This type of hammer mill is the ideal choice for applications requiring a large feed opening. It is suitable for continuous jobs with either hourly output or reduction ratio. These machines have rigid steel plate frames that resist shock and failure from fatigue. The adjustable breaker plates also compensate for wear.

The Traveling Breaker Plate Mill is a non-clog hammer mill. This engineering allows a Slugger Crusher to reduce rock, clay, shale and bauxite to or smaller. It can reduce wet, sticky materials to a size suitable for further refinement. Its self-cleaning breaker plates reduce maintenance and service costs.

These mills are overrunning machines, reducing material on breaker plates and then crushing on grates. Their design is for operations that need processed feed before reaching the discharge area. Both models have very rugged construction for considerable material reduction.

This machine's name comes from its ability to reverse the direction of the rotor. This rotor supports the hammers, bringing fresh grinding edges into action. The reversible capabilities lower the frequency of servicing. Our reversible hammer mills increase production, double the life of your hammers, and reduce maintenance costs. Learn more about Williams reversible hammer mills.

This machine's name comes from its ability to reverse the direction of the rotor. This rotor supports the hammers, bringing fresh grinding edges into action. The reversible capabilities lower the frequency of servicing. Our reversible hammer mills increase production, double the life of your hammers, and reduce maintenance costs.

This type of hammer mill has rigid hammers rather than swing mounted. This design makes the machine effective for the pulverization of soft, fibrous, or bulky materials into fine powders. It is also suitable for the reduction of friables like coal. Each ridged arm breaker has many edges that can be indexed and presented as wear occurs. Learn more about our rigid arm breaker machines.

This type of hammer mill has rigid hammers rather than swing mounted. This design makes the machine effective for the pulverization of soft, fibrous, or bulky materials into fine powders. It is also suitable for the reduction of friables like coal. Each ridged arm breaker has many edges that can be indexed and presented as wear occurs.

good quality double rotor hammer crusher for fine stone line 2020 top brand portable mobile cone crusher plant

Dewo machinery can provides complete set of crushing and screening line, including Hydraulic Cone Crusher, Jaw Crusher, Impact Crusher, Vertical Shaft Impact Crusher (Sand Making Machine), fixed and movable rock crushing line, but also provides turnkey project for cement production line, ore beneficiation production line and drying production line. Dewo Machinery can provide high quality products, as well as customized optimized technical proposal and one station after- sales service.

The hammer crusher is a crusher that directly crushes materials with a maximum particle size of 600-1800 mm to 25 or less. Hammer crusher is a kind of equipment for crushing materials in the form of impact. It is divided into single rotor and double rotor.This hammer mill crusher can save you cost and time because of shaping materials one time.

Hammer Crusher [ Capacity ]: 575 t/h [ Applicable Material ]: Hammer crusher is the most common of stone crushing equipment. It is also called hammer mill. It has high production capacity, low energy consumption, simple structure, reliable quality, easy maintenance, etc.

The types of stone hammers crushers: single-stage hammer crusher, high-efficiency hammer crusher, sand making machine, vertical shaft hammer rock crusher, reversible hammer crusher, double rotor hammer crusher, ring hammer crusher. Routine Maintenance. 1. It should contact the upper and lower procedures related to the machine before starting to ...

High Quality Heavy Hammer Crusher In Road Construction Application , Find Complete Details about High Quality Heavy Hammer Crusher In Road Construction Application,Heavy Hammer,Good Performance Stone Rock Crushing Machine,Mining Widely -used Crushing Machine Price List from Crusher Supplier or Manufacturer-Luoyang Zhongde Heavy Industries Co., Ltd.

PC Hammer Crusher This machine is widely used in industries of mining, building materials, chemical industry, metallurgy, fodder, etc. It can crush materials with medium or less hardness into medium or fine crushing, such as limestone, calcite, talc, gypsum, coal, coke, clay, slag, etc.

Hammer Crusher,Hammer Mill Crusher,Hammer Stone Crusher for Sale,Hammer Impact Crusher Manufacturers single-stage hammer crusher - Cone crusher, Stone ... Operating principle of Hammer Crusher: The motor drives the rotor to rotate the hammer crusher with high speed through the belt, and on the rotor there are a series ...

Best Quality Small Stone Hammer Crusher Crushing Machine With Good Price For Sale , Find Complete Details about Best Quality Small Stone Hammer Crusher Crushing Machine With Good Price For Sale,Stone Hammer Crusher Machine,Stone Crusher Hammer,Hammer Crusher from Supplier or Manufacturer-The Nile Machinery Co., Ltd.

double rotor fine hammer crusher

Double rotor fine hammer crusher function can crush the moisture content which is below 20%, it can be produced normally, the output is high, and the return is small (the crusher is used for crushing, and then sieving, the finished product below 2.5mm can be beaten to 75%-85%), the spindle wheel core is free of wear and does not need to be replaced. It only takes 30 minutes to change the hammer. Except for normal maintenance, the equipment has no maintenance except for wearing parts.

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hammer crusher | hammer mill crushers for sale jxsc mine

Hammer Crusher Application Field Mining, metallurgy, building material, cement, quarrying, gravel & sand making, aggregate processing, recycling, and chemical industry, etc. Suitable Material Limestone, slag, pebble, rock gold ore, salt, concrete, coal, coke and other materials in the primary/secondary crushing and fine crushing operations.

Hammer stone crusher is a kind of equipment that crushes materials in the form of impact. Crushing the size of 600-1800 mm material to 25m or less. Hammermill machine can not only be used in stone crusher plant, sand plant, but also can replace the cone crusher in the mineral processing.

JXSC hammer mill machine that hammerhead adopts a new technology cast which wear-resistant and impact-resistant. The airframe structure of the hammer mill is seal which solves the problems of dust pollution and dust leakage in the crushing workshop. And it is easy to maintain.

1. Hammerhead uses new cast technology which with wear-resistant and impact-resistant characteristic. 2. Can adjust the granularity size. 3. The seal structure that solves the problems of dust pollution and dust leakage in the crushing workshop. 4. The overall design of hammer crushing equipment has the advantages of beautiful appearance, compact structure, few wearing parts, convenient maintenance, etc.

Hammermill crusher mainly rely on impact energy to complete the crushing of materials. When the hammer mill rock crusher works, the motor drives the rotor to rotate at high speed, and the material enters the crusher cavity evenly. The hammerhead with high speed turns impacts and tears the material lead to the materials are crushed.

At the same time, the material from the high-speed rotating hammerhead to the baffle and screen strip in the frame under the gravity effect. The material larger than the size of the screen hole remains on the screen plate and continues to be hit and ground by the Hammer. Then finally through the sieve plate discharge machine until the crusher material size discharge.

The advantages of the hammer: The ratio of crushing is large, generally is 10-25, high up to 50. High production capacity. uniform products. Less over-powder phenomenon. Simple structure, light equipment quality. Simple operation and maintenance, etc. The series hammer crusher products are suitable for crushing all kinds of medium hardness and brittle materials, such as limestone, coal, salt, gypsum, alum, brick, tile, coal gangue and so on. The compressive strength of the crushed material shall not exceed 150 MPA.

The series of crushers are mainly used in cement, coal preparation, power generation, building materials, and compound fertilizer industries. It can crush the raw materials of different sizes into uniform particles for the next working procedure. Reliable mechanical structure, high production efficiency, good applicability.

But the hammer crusher also has some disadvantages, such as the hammer and grate screen wear quickly. When crushing hard materials, they wear out faster. When crushing sticky wet materials, it is easy to plug the screen seam of the grate. Therefore, it is easy to cause shut down, so the moisture content of the material should not exceed 10 %. When milling hard objects, the hammer and lining plate have big wear. And the consumptive metal material is much, often needs to replace the wear-and-tear piece.

Jiangxi Shicheng stone crusher manufacturer is a new and high-tech factory specialized in R&D and manufacturing crushing lines, beneficial equipment,sand-making machinery and grinding plants. Read More

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