Description

When the Symons brothers Invented the cone crusher, they employed the principle wherein the length of the crushing stroke was related to the free fall of material by gravity. This permitted the material being crushed to fall vertically in the crushing chamber; and in effect, caused the particles to be crushed in a series of steps or stages as the particles got smaller due to the crushing action. This also helps to reduce the rate of wear of the liners since the sliding motion of the particles is minimized.

Recognizing that the Symons principle of crushing is the most efficient means of ore and aggregate reduction in hard rock applications, the engineers used this same principle in the design on the hydrocone.

The cavity design eccentric (head) speed and throw of the hydrocone are equivalent to the Symons Cone Crushers.

The need for increased crushing capacity within the volume or space occupied by existing crushers was one of the objectives in the design of the cone crusher.

Versatility in the form of having the ability to perform in a wide range of applications without the need for a change in major assemblies was another objective in the design. Ease of maintenance and remote setting capability also were part of the design parameters the market requires.

CONE CRUSHER MODELS & TECHNICAL SPECIFICATIONS

There is no startling revelation to the fact that the mining industry as a whole is generally moving toward the use of larger equipment to process ores in quantities far greater than what was even considered a decade ago. Trucks and shovels have led the way in extra large machines and many other manufacturers have followed suit in the development of so-called “supers” in their line of equipment.

In order to keep pace with the industry, crusher manufacturers have also enlarged the size of their equipment. There is now on the market, a Gyratory crusher capable of accepting a 72″ diameter piece of ore. Primary jaw crushers have also increased in size. It is inevitable, therefore, that larger secondary cone crushers would also be required to complement the other equipment used to process these large quantities of ore. This super-size secondary cone crusher is the SYMONS 10 Ft. Cone Crusher.

Until 1973, the largest cone crusher built was the 7 Ft. Extra Heavy Duty crusher, which is currently used in the majority of the mining operations throughout the world. The 10 Ft. crusher, when compared to the 7 Ft. Extra Heavy Duty Crusher, is approximately 1½ times larger in physical dimensions; three times heavier; will accept a maximum feed size which is approximately twice as large; and will crush at approximately 2¼ times the rate of the 7 Ft. machine at identical closed side settings. It will be the largest cone crusher built in the world.

The preliminary design studies for the 10 Ft. cone crusher were made in the early 1950’s. At that time, engineering investigations were made to determine the following:

1. The general, physical shape of the machine;
2. The capability of our shop to machine and assemble this size crusher;
3. The theoretical capacity of the machine in tons per hour at various closed side settings; and
4. An approximate cost to manufacture the machine.

The conclusions of this investigation were all positive – the crusher could be built and at a cost that would be in line with its size and capacity and also with other size crushers. After that preliminary study, the project became dormant for several years.

The project was reactivated and this time general assembly drawings were made which incorporated many improvements in the crusher such as pneumatic cylinders in place of the conventional, springs for tramp iron release, a two-piece main frame a dynamically balanced design of the internal moving parts of the crusher, and an automatic clearing and adjusting mechanism for the crusher. At this stage of development we felt we were ready to build a 10 Ft. crusher for any mine that was willing to try one. Unfortunately, the conservative posture of the mining industry did not exactly coincide with our sales plans. This, added to the popularity of the autogenous mill concept at the time, led to another lull in the 10 Ft. development program.

The project was reactivated again in 1970, this time primarily at the request of one of the large Minnesota Iron Range mining companies. We then undertook a comprehensive market research study to determine if there was a need for this size crusher by the mining industry in general, rather than just the iron ore industry. We talked not only to the iron ore people but to the copper people and persons connected with the other metallic ores as well. The acceptability of this large crusher was also discussed with the aggregate industry. After interviews with many of the major mining companies, the decision was made to complete the entire engineering phase of the development program and to actively solicit a customer for this new crusher. We spent approximately $85,000 on engineering work and tests on the gamble that we could find a customer. I speak of a gamble because during our market research study we continually were told “my company would be very interested in buying a 10 Ft. crusher, but only after we have seen one in operation”.

The actual building and test of the first prototype unit without a firm commitment for a sale was an economic impossibility. We were now at the point where we needed to sell at least one unit in order to prove not only the mechanical reliability of the machine, but the economic justification for its purchase as well. Needless to say, when the order for two SYMONS 10 Ft. cone crushers was received, we felt we were now on the way toward completion of the development program.

A Symons Cone Crusher

Perhaps at this point it might be apropos to examine the crusher itself. It will stand 15′-6” above its foundation, the overall height will be 19′-4-¼”. At its greatest diameter, in the area of the adjustment ring, it will be approximately 17′-6″. It will weigh approximately 550,000 lbs. Under normal crushing conditions, the crusher will be connected to a 700 HP motor. A 50 ton. overhead crane is required to perform routine maintenance on this crusher.

The main shaft assembly will weigh approximately 92,000 lbs. and the bowl assembly approximately 95,000 lbs. The mantle and bowl liner, cast from manganese steel, will weigh approximately 13,000 lbs. and 25,000 lbs. respectively.

The throughput capacity of the Standard will be approximately 1300 TPH at a 1″ closed side setting and 3000 TPH at a 2-½” closed side setting. The throughput capacity of the SHORT HEAD will be approximately 800 TPH at ¼” closed side setting and 1450 TPH at a 9/16″ closed side setting.

Persons familiar with the design of a conventional 7 Ft. SYMONS cone crusher will recognize that the design of the 10 Ft. is quite similar to it. As a matter of fact, we like to say that the design of the 10 Ft. is evolutionary rather than revolutionary, because all the reliable features of the SYMONS cone crusher were retained and the only changes that were made were those that added to the convenience of the operator, such as automatic clearing and automatic adjustment. From a mechanical point of view the stresses generated due to crushing loads are less in the 10 Ft. crusher than in the existing 7 Ft. Extra Heavy Duty cone.

Why Install a Cone Crusher

One of our senior engineers who has long since retired told me that he had the occasion many years ago to make a presentation of a newly designed crusher to a prospective customer. He carefully prepared a rather detailed description of the crusher which included all the features that his new machine had when compared to the customer’s existing machine. The presentation itself took about one hour and after that period the customer leaned back in his chair and said, “That’s all well and good, but will it crush rock?” In effect, the customer was; saying that all the features in the world were of no use to him if the crusher did not perform its basic function to crush rock and ultimately make profits for the owner. Using today’s financial terminology he was asking the engineer to economically cost justify the purchase of the crusher.

The working day of the contemporary manager or project engineer evolves around making decisions to economically justify a piece of equipment or a new operation. In our development program of the 10 Ft. cone crusher, we felt that the economic justification, from the customer’s point of view, was just as important to develop as the engineering aspects of the program. So we developed a three-part program to examine the economics of installing a 10 Ft. crusher. First we talked in wide generalities concerning the use of a 10 Ft. crusher. Secondly, we discussed the ramifications of using a 10 Ft. crusher versus 7 Ft. crushers in a completely new plant being considered for the future. Thirdly, we examined how a 10 Ft. crusher could be used to its best advantage in a plant that is being expanded.

The first consideration was the economic generalities of installing the crusher, or more specifically, what questions regarding the installation are pertinent to every crushing plant. Usually, the initial comparison which is made between a 7 Ft. crusher and a 10 Ft. crusher is that of price versus capacity. Theoretically, the capacity of a 10 Ft. crusher is 2¼ times that of a 7 Ft. while the selling price is approximately 3 times that of the 7 Ft. On that basis alone, it would appear that the 10 Ft. could not be justified. However, this is an incomplete picture. Recent cost estimates show that considerable savings are realized when the entire physical plant structure is considered. Because fewer machines are required to crush an equivalent amount of ore, the size of the buildings can be reduced, thereby decreasing the capital investment of buildings and allied equipment used as auxiliaries for the crusher.

Total manpower requirements to operate and maintain the plant is another of the generalities which were considered. Fewer crushers normally require less personnel to operate and perform maintenance, Manpower requirements obviously play a large part in the profitability of a plant. Therefore, it follows that using a 10 Ft. in place of multiple 7 Ft. units should be more profitable from the standpoint of manpower. We should, however, clarify one point regarding normal maintenance of the 10 Ft. crusher which is commonly misunderstood; namely, the periodic changeout of manganese liners in the crusher. The normal time period between manganese changes would not be significantly different between the 7 Ft. and a 10 Ft. because the wear rate, that is, the pounds of liner worn away per ton of ore crushed, will remain the same. Consequently, if a set of liners in a 7 Ft. crusher, lasted six weeks, a 10 Ft. crusher in the same operation would also last approximately six weeks. However, since the total amount of ore crushed will be greater, the maintenance costs per liner changeout will be less on the 10 Ft. crusher.

Another point for consideration is that the 10 Ft., cone crusher is a secondary crusher and normally would be fed with the product of a gyratory crusher. Since the 10 Ft. can accept a larger feed than a 7 Ft. crusher, it is possible to increase the open side setting of a gyratory crusher, thereby, allowing a greater volume of feed to pass through the crusher. Because of this, it is conceivable that a smaller primary crusher could be used in order to obtain a given quantity of ore.

A good salesman could expound on a multitude of ideas for using 10 Ft. crushers in place of 7 Ft. crushers in a new plant, but in the final analysis, the deciding factor as to whether or not the 10 Ft. crushers should be used will be the anticipated over-all plant capacity. Several studies have indicated that as a general rule of thumb the break even point for using 10 Ft. crushers in place of 7 Ft. crushers is a plant which will have an overall ore treatment capacity of approximately 40,000 TPD or approximately 8,000,000 TPY. Anything less than that figure should indicate the use of conventional 7 Ft. crushers. Obviously a small four stage crushing plant in which the third stage crusher was a 7 Ft. Standard and the fourth stage consisted of two 7 Ft. SHORT HEAD cone crushers, would not improve economically by the use of one 10 Ft. Standard cone crusher and one 10 Ft. SHORT HEAD cone crusher in place of the 7 Ft. crushers.

A study was made which considered a plant to be built using three different approaches of a conventional crushing-grinding operation. The plant which was being considered would be crushing taconite similar to that found in the Iron Range. The end product of the crushing was 5/8″ rod mill feed and in this example the plant capacity was to be approximately 13.5 million TPY of ore processed to eventually produce approximately 4¼ million TPY of iron ore pellets. The study arbitrarily chose a four-year period of operation so that operating costs would be included and also because a four-year period is the usual comparison basis for calculating return on investment. In this example the primary crusher as well as the fine crushing plant would be operated fourteen shifts per week.

In our economic analysis of the 10 Ft. crusher development program, we also studied how this crusher could be used to best advantage when planning expansion of an existing plant. Before delving into the actual dollars and cents of several variations of expansion plans, several preliminary questions must be answered in the affirmative:

1. Is there physical space available for the addition of a 10 Ft. crusher?
2. Can existing foundations be altered or is there room for new foundations?
3. Is crane capacity available? A 50 ton crane is required for normal maintenance of this machine.
4. Is existing conveyor capacity adequate or can it be altered to accept the additional loads?
5. Is screen capacity adequate? A 10 Ft. Standard will usually require at least two 8 x 20 screens and a SHORT HEAD at least one 8 x 20 screen to adequately service it.

After these questions have been answered and the costs involved in these alterations examined, a comparison can be made between the use of 10 Ft. and 7 Ft. crushers.

Since each plant is unique, the relative merits of the 10 Ft. crusher must be examined on an individual plant basis. Again, as a general rule of thumb, it has been found that the most benefit can be achieved in those plants which presently contain a four-stage crushing plant in which the first two stages of crushing are gyratory crushers. Studies have shown that converting the second stage gyratory crusher to a 10 Ft. Standard crusher shows most potential because the major auxiliaries required for the crusher, such as crane, conveyors, etc., are already large enough to accommodate the increased capacity of the 10 Ft.

As one possible solution, we suggested that the two 30 x 70 secondary gyratory crushers be replaced by two 10 Ft. Standard cones. These crushers could then send approximately 3600 TPH of minus 3″ material to the fine crushing plant. The two existing 7 Ft. Standard crushers could be converted easily to SHORT HEAD crushers and two new 7 Ft. SHORT HEAD crushers added to the existing vacant foundations.

In Summary, we feel that the Symons cone crusher has a very definite place in the future of the mining industry and we intend to move steadily ahead with its progress. However, we have learned a few lessons along the way.

Initially, the development of these “super” size machines is an extremely expensive proposition. We know that if our company alone, attempted to completely design, manufacture, erect, and test a machine in this size range, it would severely tax our financial resources.

We found that it is also extremely difficult to sell the proto-type unit. The mining industry is a conservative industry and generally will buy something only when someone else has tested it.

We found that “super” size equipment also presents some problems for our manufacturing facilities. The manufacture of one of these units puts a large dent into the production schedule of many of the smaller conventional units. In our enthusiasm to build a bigger newer machine, we continually remind ourselves that the smaller conventional units are still our “bread and butter” units.

On the positive side, we found that our reputation as a crusher manufacturer was enhanced because of what our customers refer to as “progressive thinking”. We listened to the suggestions of the mining industry in attempting to give them what they wanted.

Perhaps you will allow me to close with a bit of philosophizing from a manufacturer’s point of view. The 10 Ft. crusher is here — ready to go into operation. Where do we go from here? A 15 Ft. cone crusher? A 20 Ft. cone crusher? Who knows? We do know that we have reached the financial limit of a development program on a machine of this size. We also know that as the size of a machine grows larger, the developmental and manufacturing risks grow larger along with it and any allowable margin for error must be minimized. We, like you, are in business to make a profit. Since larger crushers usually mean a fewer number of crushers, we must examine the profit picture from aspects of the sale. I think I speak for other manufacturers as well when I say that “bigness” in machines reflects “bigness” in development costs as well. If the mining industry wants still larger equipment in the future, the industry should prepare itself to contribute to the development program of those machines.

Hydrocone Cone Crusher

A multi-cylinder Hydraulic Cone Crusher, the Hydrocone Cone Crusher can be used in either the second or third stage of crushing by merely changing liners and adaptors. It can produce the full product range that the combination of a comparable sized Standard and Short Head can produce. It makes the machine much more versatile. It allows for much more standardization. The value of this feature is one where spare parts investment in the form of major assemblies is minimized.

The Hydrocone Cone Crusher uses hydraulic clamping cylinders to hold the bowl securely in the threads. These cylinders are located in pockets between a clamp ring and the adjustment ring.

Hydrocone Cone Crusher Crushers are equipped with a fingertip hydraulic control that adjusts the crusher setting for optimum performance, while the crusher is operating under load.

All operator controls are conveniently mounted on a remote control console to eliminate the need for an operator to approach the crusher during operation. Over a period of years we have developed a unique engineering knowledge about the effects of cone crusher design parameters such as speed, throw and cavity design on crusher productivity.

Hydraulic Tramp Release

Each Hydrocone Cone Crusher features dual function hydraulic cylinders that provide overload protection and a safe and fast way to clear a jammed cavity. Should the crusher become plugged, the operator merely pushes levers on the remote control console to clear the cavity.

  Hydrocone Cone Crusher

It can produce the full product range that the combination of a comparable sized Standard and Short Head can produce. It makes the machine much more versatile. It allows for much more standardization. The value of this feature is one where spare parts investment in the form of major assemblies is minimized.

The Hydrocone Cone Crusher uses hydraulic clamping cylinders to hold the bowl securely in the threads. These cylinders are located in pockets between a clamp ring and the adjustment ring.

Hydrocone Cone Crusher Crushers are equipped with a fingertip hydraulic control that adjusts the crusher setting for optimum performance, while the crusher is operating under load.

All operator controls are conveniently mounted on a remote control console to eliminate the need for an operator to approach the crusher during operation. Over a period of years we have developed a unique engineering knowledge about the effects of cone crusher design parameters such as speed, throw and cavity design on crusher productivity.

Hydraulic Tramp Release

Each Hydrocone Cone Crusher features dual function hydraulic cylinders that provide overload protection and a safe and fast way to clear a jammed cavity. Should the crusher become plugged, the operator merely pushes levers on the remote control console to clear the cavity.

Mono Cylinder Hydraulic Cone Crusher

The Hydraulic Cone Crusher uses hydraulic tramp release cylinders and accumulators to hold the adjustment ring against the main frame seat. There is only one angular surface between the main frame and the adjustment ring which also has a radial contact point in the lowermost area. When a piece of tramp goes through the crusher, the oil is forced into the accumulators allowing the adjustment ring to raise and pass the tramp.

The tramp release cylinders coupled with the accumulators return the crusher to its original setting after the tramp has been passed.

The tramp release cylinders are secured to the adjustment ring and the lower portion of the main frame through clevises. This allows the crushing forces to be transferred directly from the frame arm locations to the adjustment ring. This relieves the main frame shell and upper flange from carrying heavy loads.

Main frame pins are also provided on the Hydraulic Cone Crusher to prevent the adjustment ring from rotating.

The Hydraulic Cone Crusher is equipped with hydraulic clearing. The tramp release cylinders which hold the adjustment ring in place are double acting cylinders. These cylinders can be pressurized in the opposite direction, after the clamping pressure has been released, to raise the adjustment ring and bowl assembly for clearing; only the weight of the adjustment ring, clamp ring, and bowl assembly, plus any residual material in the bowl hopper raises.

The distance through which the adjustment ring can be raised is more than adequate to clear a crusher which has been jammed.