rock crusher history
History tells us,it was in 1830, the firstUS patent was issued on a rock crushing machine. It covered a device which, in a crude way, incorporated the drop hammer principle later used in the famous stamp mill, whose history is so intimately linked with that of the golden age of mining. In 1840,another patent was issued, which comprised a wooden box containing a cylindrical drum apparently of wood also on which a number of iron knobs, or hammers, were fastened; the expectation was that this drum, when revolved at about 350 RPM, would shatter the rock fed into the top of the box. This device, although it was conceived as an impact crusher and thus would rate as a forerunner of the hammermill, bore a somewhat closer resemblance to the single sledging-roll crusher. There is no evidence that either of these early inventors carried their work through to fruition.
Eli Whitney Blake invented the first successful mechanical rock breaker, the Blake jaw crusher patented in 1858. Blake adopted a mechanical principle familiar to all students of mechanics, the powerful toggle linkage. That his idea was good is attested to by the fact that the Blake type jaw crusher is today the standard by which all jaw crushers are judged, and the leading machine of the class for heavy duty primary crushing service.
The gyratory principle was the basis of several rudimentary designs, patented between 1860 and 1878, noneof which embodied practical mechanical details at least, not in the light of our present-day knowledge of the art. Then, in 1881, Philetus W. Gates was granted a patent on a machine which included in its design all of the essential features of the modern gyratory crusher. The first sale on record antedates the patent by several months, a No. 2 crusher, sold to the Buffalo Cement Co. in 1880. That was the first of several thousand gyratory crushers which carried the name of Gates to the far corners of the earth.
An interesting sidelight of these early days occurred in 1883 when a contest was staged between a Blake jaw crusher and a Gates gyratory crusher. Each machine was required to crush 9 cubic yard of stone, the feed-size anddischarge settings being similar. The Gates crusher finished its quota in 21 minutes, the Blake crusher in 65 minutes, which must have been a sad disappointment to the proponent of the Blake machine, who happened to be the challenger.
For some years after these pioneer machines were developed, requirements, viewed in the light of present practice, were very simple. Mining and quarrying, whether underground or open-pit, was done by hand; tonnages generally were small, and product specifications simple and liberal.
In the milling of precious metal ores, stamp mills were popular as the final reduction machine. These were generally fed with an ore size that could be produced handily by one break through the small gyratory and jaw crushers which served as primary breakers. Even in large underground mining operations there was no demand for large crushers; increased tonnage requirements were met by duplicating the small units. For example, in 1915, at the huge Homestake operation, there were no less than 20 Gates small gyratory crushers sizes No. 5 and 6 to prepare the ore for the batteries of >2500 stamp mills.
Most commercial crushed stone plants were small, and demand for small product sizes practically non-existent. Many plants limited output to two or three products. Generally the top size was about 2.5 to 3 ring-size; an intermediate size of about 1.5 or thereabouts, might be made, and the dust, or screenings, removed through openings of about 0.25. In ballast plants the job was even more simple, one split and an oversize re-crush being all that was needed.
Many small process plants consisted of one crusher, either jaw or gyratory rock crushers, one elevator and one screen. Recrushing, if done, was taken care of by the same machine handling the primary break. The single crusher, when of the gyratory type, might be any size from the No. 2 (6 opening) to the No. 6 with 12-in. opening.
When demand grew beyond the capabilities of one crusher, it was generally a simple matter to add a second machine to take care of the recrushing or secondary crushing work. A popular combination, for example, consisted of a No. 6 primary and a No. 4 secondary, or possibly a 20- x 10-in., or 24- x 12-in. primary jaw, followed by one of the small gyratories. When the business outgrew the capacity of this sort of plant, it was not unusual to double up, either in the same building, or by erecting an entirely separate plant adjacent to the original one.
Crusher manufacturers were not standing still during these early years. In the gyratory line, for example, the No. 2 was the first popular size, and larger machines were developed from time to time up to the No. 6, then the No. 7.5
The steam shovel began to change the entire picture of open-pit working. With the steam shovel came the really huge No. 8 crusher, with its 18 receiving opening. Up to this time the jaw crusher had kept pace with the gyratory, both from the standpoint of receiving opening and capacity, but now the gyratory stepped into the leading position, which it held for some 15 years. Once the ice was broken, larger and larger sizes of the gyratory type of crusher were developed rapidly, relegating the once huge No. 8 machine to the status of a secondary crusher. This turn toward really large primary crushers started just a few years before the turn of the century, and in 1910 crushers with 48 receiving openings were being built.Along about this time the jaw crusher suddenly came back to life and stepped out in front with a great contribution to the line of mammoth-size primary crushers: the 84 x 60 machine built by the now Joy Mining Machinery for a trap rock quarry in eastern Pennsylvania. This big crusher was followed by a No. 10 (24 opening) gyratory crusher for the secondary break. Interest created by this installation reawakened the industry to the possibilities of the jaw crusher as a primary breaker, and lines were brought up-to-date to parallel the already developed gyratory lines.
Although his machines never came into general use in the industry, Thomas A. Edison ranks as a pioneer in the development of the large primary breaker and credited with the announcement of a very interesting and constructive bit of reasoning, which was the basis of his development. Concerned at the time with the development of a deposit of lean magnetic iron ore where he was using a number of the small jaw crushers then available for his initial reduction. Realizing that to concentrate this ore at a cost to permit marketing it competitively meant cutting every possible corner, he studied the problem of mining and crushing the ore as one of the steps susceptible of improvement.
In approaching the problem, Edison reasoned that the recoverable energy in a pound of coal was approximately equal to the available energy in one pound of 50% dynamite; but the cost per pound of the dynamite was about 100 times that of the coal. Furthermore, a large part of the dynamite used in his mining operation was consumed in secondary breaking to reduce the ore to sizes that the small primary crushers would handle. The obvious conclusion was that it would be much cheaper to break the large pieces of ore by mechanical rather than by explosive energy.
With that thesis as a starting point, he set out to develop a large primary breaker, a development which culminated several years later in the huge and spectacular 8 x 7 Edison rolls. A description of the action of this machine will be found in a later section of this series. During the early years of the present century these giant machines created considerable interest, and several were installed in this country. However, they never became popular, and interest swung back to the more versatile gyratory and jaw types. Edison rolls were also developed in smaller sizes for use as secondary and reduction crushers. In his own cement plant Edison used four sets of rolls operating in series to reduce the quarry-run rock to a size suitable for grinding.
The size requirement of the primary rock crusher is a function of grizzly openings, ore chute configuration, required throughput, ore moisture, and other factors. Usually, primary crushers are sized by the ability to accept the largest expected ore fragment. Jaw crushers are usually preferred as primary crushers in small installations due to the inherent mechanical simplicity and ease of operation of these machines. Additionally, jaw crushers wearing parts are relatively uncomplicated castings and tend to cost less per unit weight of metal than more complicated gyratory crusher castings. The primary crusher must be designed so that adequate surge capacity is present beneath the crusher. An ore stockpile after primary crushing is desirable but is not always possible to include in a compact design.
Many times the single heaviest equipment item in the entire plant is the primary crusher mainframe. The ability to transport the crusher main frame sometimes limits crusher size, particularly in remote locations having limited accessibility.
In a smaller installation, the crushing plant should be designed with the minimum number of required equipment items. Usually, a crushing plant that can process 1000s of metric tons per operating day will consist of a single primary crusher, a single screen, a single secondary cone crusher, and associated conveyor belts. The discharge from both primary and secondary crushers is directed to the screen. Screen oversize serves as feed to the secondary crusher while screen undersize is the finished product. For throughputs of 500 to 1,000 metric tons per operating day (usually 2 shifts), a closed circuit tertiary cone crusher is usually added to the crushing circuit outlined above. This approach, with the addition of a duplicate screen associated with the tertiary cone crusher, has proven to be effective even on ores having relatively high moisture contents. Provided screen decks are correctly selected, the moist fine material in the incoming ore tends to be removed in the screening stages and therefore does not enter into subsequent crushing units.
All crusher cavities and major ore transfer points should be equipped with a jib-type crane or hydraulic rock tongs to facilitate the removal of chokes. In addition, secondary crushers must be protected from tramp iron by suspended magnets or magnetic head pulleys. The location of these magnets should be such that recycling of magnetic material back into the system is not possible.
Crushing plants for the tonnages indicated may be considered to be standardized. It is not prudent to spend money researching crusher abrasion indices or determining operating kilowatt consumptions for the required particle size reduction in a proposed small crushing plant. Crushing installations usually are operated to produce the required mill tonnage at a specified size distribution under conditions of varying ore hardness by the variation of the number of operating hours per day. It is normal practice to generously size a small crushing plant so that the daily design crushing tonnage can be produced in one, or at most two, operating shifts per working day.
rock crusher - eastman rock crusher
Granite is not easy to crush to sand, main equipment has PE-7501060 jaw crusher (coarse crusher), HP300 cone crusher (fine crusher), bin, 490110 vibrating feeder, B1000x22 conveyor belt, B1000x30m conveyor belt, B800x31 conveyor belt, 4YK2460 vibrating screen, etc. contact us!
In this case, we recommend the use of a PCZ1308 heavy hammer crusher with a feed size of 930x650mm, the feed particle size is less than 600mm, the motor power is 4P 132Kw, and the processing capacity of the equipment is 100-180t/h.
Eastman is a typical direct selling enterprise with green and standardized production plants. All the delivery of the equipment will be completed within the delivery period signed by the contract to ensure the smooth commissioning of the equipment.
Rock crushers have a wide range of suitable material to choose from, whether its soft or hard, or even very hard, rock crushers can reduce those large rocks into smaller rocks, gravel, or even rock dust.Here are some typical materials that break or compress by industry crushers, such as Granite, quartz stone, river pebble, limestone, calcite, concrete, dolomite, iron ore, silicon ore, basalt and other mines, rocks and slag.
Understanding the stages of crushing process and the types of crushers that best fit each stage can simplifies your equipment selection. Each type of crusher is different and used to achieve a certain end result.
Similarly, a certain output is expected at the end of each crushing stage for the next phase of the process. Aggregate producers who pair the correct crusher to the correct stage will be the most efficient and, in turn, the most profitable.
A jaw crusher is a compression type of crusher. Material is reduced by squeezing the feed material between a moving piece of steel and a stationary piece. The discharge size is controlled by the setting or the space between those two pieces of steel. The tighter the setting, the smaller the output size and the lower the throughput capacity.
As a compression crusher, jaw crushers generally produce the coarsest material because they break the rock by the natural inherent lines of weakness. Jaw crushers are an excellent primary crusher when used to prepare rock for subsequent processing stages.
Although the chamber is round in shape, the moving piece of steel is not meant to rotate. Instead, a wedge is driven around to create compression on one side of the chamber and discharge opening on the opposite side. Cone crushers are used in secondary and tertiary roles as an alternative to impact crushers when shape is an important requirement, but the proportion of fines produced needs to be minimized.
An impact crusher uses mass and velocity to break down feed material. First, the feed material is reduced as it enters the crusher with the rotating blow bars or hammers in the rotor. The secondary breakage occurs as the material is accelerated into the stationary aprons or breaker plates.
Impact crushers tend to be used where shape is a critical requirement and the feed material is not very abrasive. The crushing action of an impact crusher breaks a rock along natural cleavage planes, giving rise to better product quality in terms of shape.
Most aggregate producers are well acquainted with the selection of crushing equipment and know it is possible to select a piece of equipment based solely on spec sheets and gradation calculations. Still, theoretical conclusions must always be weighed against practical experience regarding the material at hand and of the operational, maintenance and economical aspects of different solutions.
The duty of the primary crusher is, above all, to make it possible to transport material on a conveyor belt. In most aggregate crushing plants, primary crushing is carried out in a jaw crusher, although a gyratory primary crusher may be used. If material is easily crushed and not excessively abrasive, an impact breaker could also be the best choice.
The most important characteristics of a primary crusher are the capacity and the ability to accept raw material without blockages. A large primary crusher is more expensive to purchase than a smaller machine. For this reason, investment cost calculations for primary crushers are weighed against the costs of blasting raw material to a smaller size.
A pit-portable primary crusher can be an economically sound solution in cases where the producer is crushing at the quarry face. In modern plants, it is often advantageous to use a moveable primary crusher so it can follow the movement of the face where raw material is extracted.
The purpose of intermediate crushing is to produce various coarser fractions or to prepare material for final crushing. If the intermediate crusher is used to make railway ballast, product quality is important.
In other cases, there are normally no quality requirements, although the product must be suitable for fine crushing. In most cases, the objective is to obtain the greatest possible reduction at the lowest possible cost.
In most cases, the fine crushing and cubicization functions are combined in a single crushing stage. The selection of a crusher for tertiary crushing calls for both practical experience and theoretical know-how. This is where producers should be sure to call in an experienced applications specialist to make sure a system is properly engineered.