- Cone Crusher Hydraulic System Operation
- Fast & Easy Control Product Size
- Protect Cone Crusher from Tramp Iron
- Cone Crusher Feed Distribution
- Crusher Foundation
- Uniform Crusher Discharge Product
- Cone Crusher Dust Seal Protects From Wear
- Fast Crusher Maintenance Reduces Downtime
- CONE CRUSHER LUBRICATION SYSTEM
- Cone Crusher Eccentric Design
- TYPES of CRUSHING CHAMBERS
- HYDRO-CONE CRUSHER CAPACITIES
- Crusher Product Screen Analysis
- How to use Crusher Product Curves
- Crushing Test Laboratory & Engineering
Here are facts about the cone crusher known as Hydrocone. This line of hydraulically adjusted gyratory crushers was developed in the smaller sizes some fifteen years ago by Allis-Chalmers to meet a demand for improved secondary or tertiary crushing units. The line is now expanded to include sizes up to 84-in. diameter cones.
This modern crusher is the result of many years of experience in building all types of crushing equipment, when the first gyratory or cone crusher, the Gates, was put into operation. Over all these years AC has followed a continuing policy of improvement in crusher engineering, changes in design being based on operating experience of crushers in actual operation.
The Hydrocone cone crusher is the logical outgrowth, a crusher having a means of rapidly changing product size or compensating for wear on the crushing surfaces a crusher which produces a better, more cubical product than any comparable crusher and a crusher so designed that it can be operated and maintained with a minimum of expense.
Cone Crusher Hydraulic System Operation
A most important fact about the Hydrocone crusher is its hydraulic principle of operation. Hydraulic control makes possible quick, accurate product size adjustments fast unloading of the crushing chamber in case of power failure or other emergency protection against tramp iron or other uncrushable materials in the crushing chamber.
Another important fact about this crusher is its simplicity of design and operation. The accompanying sketch shows the simplicity of the Hydrocone crusher’s principle of operation. The mainshaft assembly, including the crushing cone, is supported on a hydraulic jack. When oil is pumped into or out of the jack the mainshaft assembly is raised or lowered, changing the crusher setting.
The downward thrust of the mainshaft assembly, as well as its gyrating and rotating motion, is carried on a highly efficient step bearing.
Gyratory motion is imparted to the crushing head by means of an eccentric at the lower end of the main shaft. The eccentric is rotated by means of a bevel gear and pinion from the countershaft.
Fast & Easy Control Product Size
Since the crushing cone is supported on a hydraulic jack, its position with respect to the concave ring, and therefore the crusher setting, can be controlled by the amount of oil in the hydraulic jack.
Speed-Set control raises or lowers the crushing shaft assembly hydraulically, and permits quick adjustment to produce precise product specifications without stopping the crusher. Speed-Set control also provides a convenient way to compensate for wear on crushing surfaces.
On Hydrocone crushers in sizes up to 48-in., the Speed-Set device is a hand-driven gear pump; on the larger sizes a motor-driven gear pump operated by push-button. On all sizes the setting can be changed in a matter of minutes by one man without additional equipment, reducing downtime materially.
Protect Cone Crusher from Tramp Iron
Protection against tramp iron or other uncrushable materials is afforded by an accumulator in the hydraulic system. This consists of a neoprene rubber oil-resistant bladder inside a steel shell. This bladder is inflated with nitrogen to a predetermined pressure higher than the average pressures encountered during normal crushing.
Ordinarily, the Automatic Reset remains inoperative, but if steel or some other foreign material should enter the crushing chamber, the oil pressure in the hydraulic jack will exceed the gas pressure in the accumulator. The bladder will then compress, allowing the oil to enter the steel shell. This permits the crushing cone to lower and discharge the uncrushable material without damage to the crusher.
After the crushing chamber is freed of the foreign material, the gas pressure in the accumulator will again exceed the oil pressure in the hydraulic system. Oil is then expelled from the accumulator shell and the crushing cone is returned to its original operating setting automatically.
The Automatic Reset returns the crushing head to its position quietly, rapidly and without shock. It also protects the crusher against packing and power surges.
|In normal operation, oil in hydraulic jack maintains position of crushing cone with respect to the concave ring. Gas pressure in accumulator exceeds oil pressure in hydraulic jack.||When tramp Iron enters crushing chamber, pressure on oil in hydraulic jack becomes greater than gas pressure in accumulator. This forces oil from hydraulic system to accumulator, allowing crushing cone to lower until tramp iron is discharged.||After tramp iron has been passed, gas pressure forces oil back to hydraulic jack. Crushing cone returns to|
original setting because same amount of oil is returned.
|Left: Bladder inside accumulator shell contracts, allowing oil from hydraulic jack to enter shell when crushing head is forced down to pass tramp iron. Right: Accumulator during normal operation.||Automatic Reset passed this manganese steel dipper tooth through a 1260 Hydrocone crusher in an iron ore operation. Dipper tooth measures approximately 12 x 7 x 2 inches. Crusher also passed steel chunk shown.|
A Hydrocone crusher will produce a cubical product with excellent size distribution and a minimum of flats and slivers. This is especially important in the crushed stone industry where a cubical stone is required to meet rigid product specifications. It is also of considerable significance in the mining industry where the elimination of large amounts of tramp oversize reduces circulating loads or makes open circuit crushing possible.
The reason why the Hydrocone crusher will produce such a uniform, cubical product is that it has a small eccentric throw with respect to the crusher setting. This means a smaller effective ratio of reduction during each crushing stroke, and therefore, the production of fewer fines and slivers. Likewise, a small eccentric throw means a small open side setting, which results in a smaller top size of the product. A large percentage of the product from a Hydrocone crusher will be of a size equal to or finer than the close side setting.
Cone Crusher Feed Distribution
For fine crushing, or in installations where the feed to the crusher is irregular, the use of a wobble plate feeder is recommended. This feeder is installed in place of the spider cap and affords a means of controlling the feed to the crusher, as well as a means of distributing the feed evenly around the crushing chamber.
Essentially, the feeder consists of a plate which is oscillated by a shaft extending down into the crusher’s mainshaft. The motion of the main shaft oscillates or “wobbles” the feeder plate. The plate is supported on a rubber mounting which permits its motion and, at the same time, positively seals the top of the spider bearing against the entry of dust. Maintenance is reduced by the use of self-lubricating bushings between the feeder plate shaft and the crusher mainshaft.
Hydrocone crushers are mounted on rubber machinery mountings in order to reduce installation costs and make it possible to locate these machines on the upper floors of crushing plants. These mountings operate without maintenance, absorb the gyrating motion of the crusher, thereby eliminating the need for massive foundations. Rubber mountings also prolong the life of the eccentric bearing, since this bearing is not subjected to the severe pounding encountered when rigid mountings are used.
Uniform Crusher Discharge Product
Cone Crusher Dust Seal Protects From Wear
The exclusion of dust and dirt from the internal mechanism of the crusher is of extreme importance from a maintenance standpoint. To accomplish this, Hydrocone crushers are equipped with one of the most effective dust seals yet devised.
This seal consists of a self-lubricating, graphite impregnated plastic ring which is supported from the head center in such a way that it is free to rotate, or gyrate, independently of the head center.
The plastic ring surrounds the dust collar with only a very slight clearance between the two parts. With the plastic ring being free to move as it is, it accommodates the rotation, gyration and vertical movement of the mainshaft assembly, maintaining the seal around the dust collar at all times. Because of its light weight and self-lubricating characteristics, wear on the plastic ring is negligible.
Fast Crusher Maintenance Reduces Downtime
The ease with which any wearing part can be replaced is of the utmost importance to any crusher operator. With this in mind, the Hydrocone crusher has been designed so that any part can be replaced by disturbing only a minimum number of other parts.
For example, the Mantalloy crushing surfaces are exposed by simply removing the top shell from the crusher. This can be done easily by removing the nuts from the studs at the top and bottom shell joint. The eccentric and hydraulic support mechanism are serviced from underneath the crusher without disturbing any of the feeding arrangements, or the upper part of the crusher.
In all phases of its design, the Hydrocone crusher has been built so that it can be serviced and put back into operation with a minimum of downtime and maintenance expense.
CONE CRUSHER LUBRICATION SYSTEM
Efficient lubrication of all wearing parts is one of the reasons why crushing costs are low with the Hydrocone crusher. On most sizes, lubrication is divided into three distinct systems, each functioning independently.
SPIDER BEARING LUBRICATION
This bearing, whether of the ball and socket type as on the smaller sizes, or of the “hour glass” design (as shown) found on the larger Hydrocone crushers, is pool lubricated. On the 51, 60 and 84-inch sizes, provision is made for introducing the lubricant from outside the topshell through the spider arm. On the smaller crushers, oil is introduced through an oil inlet in the spider cap. On all sizes, oil is retained in the bearing by a garter type oil seal located in the base of the spider bearing.
Step Bearing, Eccentric, Gear Lubrication
All Hydrocone crushers are provided with a compact external lubrication system consisting of an oil storage tank, an independently motor driven oil pump, a pressure type oil filter and a condenser type cooler.
Cool, clean oil is pumped into the crusher from the conditioning tank, lubricating first the three-piece step bearing assembly. The oil then travels up the inner surface of the eccentric, lubricating the eccentric bearing and mainshaft.
At the top of the eccentric the oil is split into two paths. Part of the oil flow passes through ports in the eccentric and down its outer surface, lubricating the bronze bottom shell bushing, driving gears and wearing ring. On the 48-in. and smaller crushers, the balance of the oil overflows the eccentric and returns over the gears to the bottom of the crusher where it flows by gravity back into the conditioning tank. On the 51-in. and larger Hydrocone crushers, any oil which overflows the top of the eccentric is returned directly to the conditioning system without coming into contact with the gears.
The lubrication system includes flow and temperature switches which protect the crusher in the event of oil flow failure or overheating.
COUNTERSHAFT BEARING LUBRICATION
On all but the 36 and 48-in. Hydrocone crushers, the countershaft bearings are of the anti-friction type with separate pool lubrication. Both ends of the countershaft bearing housing are sealed by garter spring type oil seals to prevent dirt or other contaminants from entering the system.
The 36 and 48-inch crushers have babbitted sleeve type bearings which are lubricated with cooled, clean oil from the external conditioning system.
Cone Crusher Eccentric Design
Rather than use one eccentric throw under all operating conditions, Hydrocone crushers are designed to operate most efficiently with a predetermined ratio of eccentric throw to crusher setting. By operating with an eccentric throw specifically selected for a given application, the most desirable crushing conditions are attained — the most economical use of Mantalloy crushing surfaces reduced crusher maintenance a more cubical product.
The eccentric throw is controlled by a replaceable bronze sleeve in the cast steel eccentric. This sleeve, being a wearing part, can be renewed readily in the field. Also, should operating conditions change, the throw or motion of the crushing head can be changed accordingly.
Because of the large choice of eccentric throws available — and the variety of crushing chambers that may be obtained — a Hydrocone crusher may be selected that will fulfill the requirements of almost any secondary or tertiary crushing operation.
They may be used in the crushed stone industries to produce a premium cubical product in the mining industries to produce a grinding mill feed having a minimum of oversize, thereby reducing circulating loads and making open circuit crushing possible. The Hydrocone crusher is used in the cement industry to reduce cement clinker prior to finish grinding.
TYPES of CRUSHING CHAMBERS
One of three general types of crushing chambers can be furnished for any size Hydrocone crusher — to suit your specific needs. The selection of the proper chamber for a given application is dependent upon the feed size, the tonnage to be handled and the product desired. A crusher already in use can be readily converted to meet changing requirements, making this machine highly flexible in operation.
COARSE CRUSHING CHAMBER
The Coarse crushing chamber affords the maximum feed opening for a given size crusher. Crushers fitted with a Coarse chamber can be choke fed, provided that product size material in the feed is removed.
The Coarse chamber has a relatively short parallel zone and is designed to be operated at a close side setting equal to or greater than the eccentric throw. For example, a crusher with a 3/8-in. eccentric throw should be operated at a 3/8-in. (or more) close side setting, and therefore a ¾-in. open side setting. Optimum capacity and product will result when operated under these conditions, as well as most economical wear on the mantalloy crushing surfaces.
One way dimension (slot size) of the feed to a crusher fitted with a Coarse chamber should not exceed two-thirds to 70 percent of the feed opening. The maximum feed size to an 848 Hydrocone crusher would therefore be about 5½-in. one way dimension.
The use of a wobble plate feeder, furnished as optional equipment, is recommended if the feed size is relatively large, if the crusher is to be operated in closed circuit, or if the feed to the crusher is irregular.
COARSE CHAMBER PRODUCT
If the Hydrocone crusher is operated with a Coarse crushing chamber, the product will average about 60% passing a square mesh testing sieve equal to the close side setting of the crusher. On certain materials which break very slabby this percentage will be somewhat lower, and on cubically breaking material the percentage will be somewhat higher. As an average, approximately 90% of the product will pass a square mesh testing sieve corresponding to the open side setting, although this percentage frequently runs higher.
INTERMEDIATE CRUSHING CHAMBER
The Intermediate crushing chamber has a feed opening somewhat less than a coarse crushing chamber, but because of its longer parallel zone, is designed to be operated at a close side setting equal to or greater than half the eccentric throw. For example, with a ¾-in. eccentric throw, the minimum close side setting would be 3/8-in.
Crushers fitted with this type of chamber can be choke fed, provided that product size material in the feed be removed ahead of the crusher. The one way dimension or slot size of the feed to a crusher should not exceed approximately half the receiving opening. A 436 Hydrocone crusher with a 5/8-in. eccentric throw could be operated at 5/16-in. close side setting and feed size should not exceed 2-in. one way dimension.
The wobble plate feeder, although not required under most circumstances, is recommended if the feed is irregular, or if the crusher is operated as a re-crusher, at a relatively close setting, or in closed circuit.
INTERMEDIATE CHAMBER PRODUCT
Because of the longer parallel zone in this crushing chamber, a somewhat greater percentage of the product will pass a square mesh testing sieve equal to the close side setting. This will usually average about 65 to 70%, with this percentage varying, depending on the material being crushed. Very frequently, 100% of the product will pass a square mesh testing sieve equal to the open side setting of the crusher.
FINE CRUSHING CHAMBER
The Fine crushing chamber has the longest parallel zone and therefore the smallest feed opening for any given size crusher. It can be operated at ratios of eccentric throw to close side setting of up to 4 to 1. With a ¾-in. throw, for example, a 236 Hydro cone crusher could be operated at 3/16-in. on the close side.
Because of their design, crushers with Fine crushing chambers cannot be choke fed, but must be equipped with the wobble plate feeder. The maximum one way dimension of the feed approaches the crusher feed opening. A 348 Hydrocone crusher can be fed with material up to 3-in. one way dimension.
FINE CHAMBER PRODUCT
The Fine crushing chamber will give the highest percentage passing the close side setting of any of the chambers discussed here. The product will average approximately 75% passing a square mesh testing sieve equal to the close side setting. Because of the long parallel zone, the top size of the product will be only slightly larger than the close side setting of the crusher.
Designs of CONE CRUSHER CHAMBERS
In addition to the three general types of crushing chambers described here, special chambers can be designed to meet varying operating requirements, giving the crusher even greater flexibility than can be obtained with these three main types.
For example, a special concave ring can be used in a 636 Hydro cone crusher which will reduce the feed opening to 5 inches and permits a two to one ratio of eccentric throw to close side setting. Thus, the crusher can be furnished to fit the exact requirements of any application.
HYDRO-CONE CRUSHER CAPACITIES
The following capacity table gives a complete range of all Hydrocone cone crusher capacities with varying crushing chambers and eccentric throws. This table shows the minimum recommended setting for any given eccentric throw, the recommended maximum one way (slot size) dimension of the feed, and the maximum recommended horsepower for any eccentric throw.
Capacities given are based on crushing dry feed from which the product size material has been removed. The material must readily enter the feed opening and be evenly distributed around the crushing chamber. The table is based on material weighing 100 lb per cubic foot crushed. Any variation from this must be accounted for.
Cone Crusher Discharge Screen Analysis SHOWS UNIFORMITY
Crusher Product Screen Analysis
The curves on the following page can be used to approximate the screen analysis of the product from any given Hydrocone crusher. These curves are only approximations, since the actual screen analysis of the product of a Hydrocone crusher will depend upon the nature of the material being crushed, the feed size and a number of other considerations which could not be taken into account in these curves. Within these limits, the curves should give fairly accurate estimates.
Note that the Coarse crushing chamber is represented as giving a product of which 60 percent will pass the close side setting, the Intermediate chamber 67½ percent and the Fine chamber 75 percent passing the close side setting. These percentages are the averages of a large number of tests and some variations from these must be expected. If material breaks slabby the percentage with a coarse crushing chamber may be as low as 50 percent; if it breaks very cubically it might be as high as 70 percent, or even higher.
How to use Crusher Product Curves
These curves have been prepared so that they can be used for any crushing chamber. To estimate the product of any Hydrocone crusher, it is necessary to know the type of crushing chamber used (Coarse, Intermediate or Fine), the close side setting and the eccentric throw.
If the crusher is a 636 Hydrocone crusher with a 3/8-in. throw and a 3/8-in. close side setting, the approximate screen analysis would be the curve which would pass through the 3/8-in. horizontal line and the vertical line representing the close side setting for the Coarse crushing chamber, which is the 60 percent passing line. If no curve passes through the precise point of intersection between the horizontal and vertical lines, an approximate curve can be sketched in which parallels the other curves. The same procedure can be used for approximating the products from any other crushing chamber.
|APPROXIMATE WEIGHTS OF MATERIALS, CRUSHED, IN POUNDS PER CUBIC FOOT|
MESH OPENINGS OF SCREENS
- How to Select the Correct CONE Crusher
- CONE CRUSHER MOTOR SIZING
- How to Install a Cone Crusher
- Cone Crusher Parts
- Cone Crusher Maintenance
Crushing Test Laboratory & Engineering
We can provide testing to solve the most difficult crushing problems. Laboratory equipment makes it possible to measure the crushing strengths and characteristics of rock or ore samples accurately, and this data is used in the selection of a crusher of proper size and type.
Impact and batch tests are frequently sufficient to indicate the type and size crusher that will be the most economical for a particular application. However, batch testing is often followed by pilot plant tests to provide additional information about large scale operations, or to observe rock or ore reduction under actual plant operating conditions.
Pilot plant tests duplicate a continuous crushing operation provide a practical demonstration of the commercial potential of the process on a pilot scale. Such tests are useful because they may disclose factors which affect the full-scale operation, favorably or otherwise, but which remain hidden in tests on limited samples.
All Laboratory tests are guided by modern scientific knowledge of crushing fundamentals and by our invaluable backlog of experience in engineering and building all types of crushing equipment — for any crushing application.
In addition to the facilities for crushing tests, the Laboratory maintains complete batch and pilot mill facilities for use in investigating an entire process. Tests in grinding, sizing, concentrating, thickening, filtering, drying, and pyro- processing can be made.