Gyratory crusher is a coarse crushing machine and is mainly used for coarsely crushing rocks with different hardness in ore beneficiation industry and other industrial departments. Other than gyratory crusher, jaw crusher is also a coarse crushing machine. In order to correctly choose and reasonably use the coarse crushing equipment, it is necessary to know the advantages and disadvantages of gyratory crusher over jaw crusher. This paper mainly deals with those advantages and disadvantages of gyratory crusher.
(1) Big depth of the crushing chamber, continuous work, high production capacity and low unit electricity consumption. Compared with the jaw crusher, the gyratory crusher has the same ore feeding width, but the production capacity of the gyratory crusher is much higher and the electricity consumption per ton of rocks is 0.5~1.2 times lower.
(2) Stable working condition, light vibration and small basic weight. Generally speaking, the basic weight of the gyratory crusher is 2~3 times of the mechanical equipment, but the basic weight of the jaw crusher is 5~10 times of the machine itself.
(3) Full chamber feeding. Large-sized gyratory crusher is able to be directly fed with crude rocks without being equipped with ore cabin and feeding machine. However, jaw crusher cannot do this and it requires rock feeding in an even manner, for this reason, ore cabin and feeding machine are needed. When the size of the rocks is larger than 400mm, heavy rock feeding machine with high price is needed.
Anyway, when choosing coarse crushing equipment, the customers should comprehensively consider all of these factors including the performance of the crusher, property of the rocks, granularity requirement of the final products, size of the manufacturing plant and the configuration conditions of the equipment so as to choose the most suitable crusher.
The present sand making technologies mainly include two types: tertiary crushing and rod mill combination sand making technology and vertical shaft impact crusher sand making technology. These two sand making methods have both advantages and disadvantages. Given this, the researchers propose the argument that users only use vertical shaft impact crusher to grind the hard rocks into sand, and through the optimization and adjustment of traditional sand making technology reasonable selection of vertical shaft crushing equipment, finally reach the goal of producing qualified sand.
Nodiscussion of primary crusher selection would be complete without a comparison of the two leading types: the standard gyratory crusher and the Blake jaw crusher. Although their fields of application overlap to a considerable degree (at least in the realm of primary crushing) there is no real conflict between these two machines; one supplements the other and, between them they very effectively cover an imposingly large proportion of the entire field of primary crushing applications. This does not mean that other types, such as the sledging rolls, for example, are not better suited for certain applications; but there are very few primary crushing jobs to which the gyratory or jaw crushers, or both of them cannot be applied with at least a fair degree of satisfaction.
Either of the two types can be built to handle the hardest and toughest rock or ore that can be economically mined or quarried. The jaw crusher, because of its box-frame construction, and simple toggle mechanism, is especially well adapted to extra heavy design for the crushing of extremely tough materials: in this respect it holds some advantage over the gyratory type, because the extra strength necessary for such work can be built into it at less cost than is required for the gyratory with its more complex shell castings. However, cases where extreme brute strength enters into the selection problem are relatively rare, either type can be used for the great majority of materials encountered in crushing practice, either in standard form or in reinforced design. Strengthening of these machines for extra-heavy duty follows certain well established practices which have been proven to be necessary or desirable. Usually it is a matter of selecting stronger metals, or adding weight in the frame, or both; seldom is it necessary to change the proportions of the working mechanism.
In most cases selection of one type or the other can be made on the basis of performance characteristics, receiving openings, space requirements, and so forth, without regard to relative strength of design. In choosing between the two for any specific application it is helpful to have a list of the salient features of each type, in a form that will permit quick and easy comparison. The following lists emphasize the favourable characteristics of each machine.
Neither machine is particularly well suited to handling very soft, or mushy materials, although the jaw crusher is superior to the gyratory for such service. Loosely cemented minerals, such as soft sandstone, will not work well in the gyratory crusher; packing on the diaphragm behind the pipe is almost certain to cause trouble. The jaw crusher will handle rock of this character if it is reasonably free-flowing. The action on all very soft materials is inclined to be sluggish and, unless it is at the same time of a free-flowing nature, packing in the crushing chamber is an ever present hazard. The jaw crusher will handle rock and ore containing a considerable proportion of loam, or similar contamination, provided that the admixture is not so viscous that it builds up on the jaw plates. The gyratory should never be used for materials containing more than a small percentage of such contamination, the allowable amount being that which the clean crushed rock will keep scoured off of the diaphragm. Flushing the diaphragm will prevent packing of this dirty material, but this practice is usually not permissible in the crushing plant.
We have had occasion to use the expression, comparable sizes, a number of times in this work, with reference to comparisons between two types of crushers, particularly the jaw and gyratory types. This expression has been used by many writers on the subject; usually without any attempt to define exactly what it implies. As a matter of fact, it is a difficult term to define with any degree of accuracy. The Old Quarryman says, It means two machines, one of which you would buy if you didnt buy the other one, providing you had enough money to buy either one of them. That comes about as near as any definition. Comparable sizes of gyratory and jaw crushers are those sizes which the engineer or operator pairs off against each other when making a selection to fit his specific problem, and these pairings may not be the same for all problems. One job may involve capacity as the most important factor; the next one may demand special emphasis on receiving opening. Obviously these different requirements may call for setting up acomparison between different sizes of one or the other type.
Usually, in selecting the primary crusher, receiving opening is the prime consideration; admitting of course that capacity must be adequate. The following list is an attempt to pair off gyratory and jaw crushers on the basis of effective receiving openings, bearing in mind that each shape of opening has its advantages for certain shape-characteristics of the feed, as has been pointed out.
Sometimes, in making a comparison of receiving openings, it is helpful to make a scale drawing of both openings, superimposing one upon the other. The rectangular jaw opening is simple and easy to layout. To draw the gyratory opening, it is necessary to know the top diameter of the crushing head; to make a complete sketch, the diameter of the spider hub and the width of the spider arms should also be known, but this information is not absolutely essential in making the comparison. Taking half the top diameter of the head as a radius, draw the circle which represents the top of the head; then, increasing the radius by the actual opening between head and concaves at their tops, draw the circle representing the concave ring at the top of the crushing chamber. Then superimpose the diagram of the jaw crusher opening, laying it in tangent to the head circle.
To facilitate this work for the line of Superior McCully gyratory crushers, we list in the following table the top diameters of the heads, and openings between head and concaves for straight-face, and non-choking, concaves.
Laying in the plan view of the spider hub and arms will, of course, give a more complete picture of the gyratory crusher receiving openings, but the picture is likely to be a littlemisleading unless it is borne in mind that the maximum diameter of the spider hub is some distance above the upper rim of the crushing chamber, and therefore does not restrict the receiving opening as much as the plan view indicates. The true effective receiving opening can only beshown in its proper proportions by tilting the plan view; that is, by an angular projection normal to a plane which is tangent to the bulge of the spider hub, and to the top of the crushing head, To draw such a view requires more information, and usually more drafting skill, than the average man has at his disposal. The circle method described in the second preceding paragraph is sufficiently close for all practical purposes.
If the material to be crushed is of a slabby nature, for example, a thinly stratified limestone or shale; the product of the jaw crusher is certain to contain slabs, some of which may be quite large, particularly so if some of the strata in the deposit are thinner than the discharge setting of the crusher. Nor is this tendency to slab in the crusher confined to stone of stratified formation. Some rocks of massive formation may contain parallel cleavage planes in certain sections of the deposit. Such material will slab in the crusher just the same as those rocks which wereformed in definite layers, or beds.
The gyratory crusher by virtue of its annular discharge opening is an effective slab breaker. This faculty, coupled with the fact that its receiving openings are especially well suited for admitting slabby feed, give it a very definite advantage over the jaw crusher in the handling of such material. In the foregoing comparison of these two leading types of primary breakers we have endeavoured to present the case for each of them in a fair and impartial manner. It would be difficult, and probably more than a little tedious for the reader, if we were to attempt a more definitive analysis or to set up fixed rules of procedure for selecting one or the other machine; a process which is always fraught with pitfalls in such a broad and empirical branch of engineering as the processing of rocks and ores. Usually the matter of choice can quickly be narrowed down to a comparison of one size in each type. These two machines may then be tabulated with respect to capital investment, capacity, power requirements, space requirements, and so forth; their receiving openings may be compared, as we have suggested, and all of the factors we have discussed in this section checked against the features and limitations of each machine to determine its ability, or inability, to fit into the plan.
Development and improvement of the jaw crusher has made some achievements in recent decades in the development process. Machinery and equipment used in the design of negative support zero suspension, hyperboloid cavity having a structural feature type, processing power and equipment efficiency are high. But to a certain extent, there are still disadvantages of jaw crusher. As a common crusher equipment, jaw crusher is the necessary equipment for crushing material its unique properties is widely used, the user has welcomed jaw crusher has broad application, but with defective equipment gradually revealed, jaw crusher has some corresponding disadvantages, such as the consumption of large jaw crusher, wear faster and so on.
First, the choice of steel. Steel selection is jaw crusher production materials, broken equipment wear is the most important requirement, jaw crusher wear parts are mainly jaws and shields, high manganese steel jaw plate adopt high quality alloy during casting the improvement of hardness and resistance material by adjusting the ratio of carbon steel. Second, the structure of the jaw crusher. Including the whole shape, appearance and component assembly design optimization components. Jaw crusher can be cast and welded chassis, you can also use other means such as a bolt adapter, so the use of jaw crusher in the field of adaptive capacity have been greatly improved. Optimized cavity shape, that changes the shape of the tooth plate section, a more rational crushing chamber curve, so that the feed and discharge to give the best fit to change the suspension height, the height of the suspension being reduced to zero or even negative suspension order increasing the level of the lower end of the movable jaw stroke.
Third, to improve the conservation system. Jaw crusher as the first breaking strength of a larger work, routine maintenance and maintenance once can not keep up, to a large extent will increase equipment wear and shorten the life of the jaw crusher. Currently degree jaw crusher plus circulation path and lubricating oil cooling system can effectively reduce equipment wear and reduce maintenance and maintenance costs of daily production.