Liner Segment for a Gyratory or Cone Crusher
Field of the invention
The present invention relates to a liner segment for a gyratory or cone crusher, to a gyratory or cone crusher comprising such liner segments, to a method of dismounting at least one liner segment from a gyratory or cone crusher, and to the use of an expandable ejector unit such as a lifting bag to dismount a liner segment from a gyratory or cone crusher.
Gyratory crushers and cone crushers are two types of rock crushing systems which generally break apart rock, stone or other material in a crushing gap between a stationary element and a moving element.
A gyratory or cone crusher is comprised of a head assembly including a crusher head that gyrates about a vertical axis within a stationary bowl attached to a main frame of the rock crusher. The crusher head is assembled surrounding an eccentric that rotates about a shaft to impart the gyratory motion to the crusher head which crushes rock, stone or other material as the material travels through a crushing gap between the crusher head and the bowl. The crushed material exits the crusher through the bottom of the crushing gap.
The eccentric can be driven by a variety of power drives, such as an attached gear, driven by a pinion and countershaft assembly, and a number of mechanical power sources, such as electrical motors or combustion engines.
While gyratory crushers and cone crushers operate according to the same principles, the longer shaft or spindle of a gyratory crusher regularly has its upper end supported by a spider bearing, whereas the shorter spindle of the cone crusher is not suspended but supported in a bearing below the gyratory head or cone. Gyratory crushers are often used as primary
crushers, i.e. heavy-duty machines designed to process large material sizes. Secondary and tertiary crushers are intended to process relatively smaller feed materials. Cone crushers are often utilised as downstream crushers.
Prior Art
Gyratory and cone crushers utilize wear parts to protect the machine from damage and perform the actual crushing of the material. The two types of wear part are the mantle and a set of several concave liners. The mantle is fixed to the main shaft and the concave liners (or simply "concaves") are fixed to the frame or topshell of the crusher. The concaves are arranged in several rows sitting on top of each other.
Wear parts may be made from chilled cast iron or from steel alloy, such as manganese steel, depending on the character of the material to be crushed and the particular class of service for which the machine is intended. Manganese steel combines extreme toughness with high wear resistance and has therefore developed into the universal choice for crushing hard, tough rock, even regardless of the class of service or the type of crusher. A common material is 12-14% manganese steel, also known as Hadfield steel. Different alloys have been used for liner segments in upper, middle and bottom parts of the crushing chamber.
Typically, both the mantle and the concaves wear and distort due to the significant pressures and impact loading forces they transmit. It is common to use backing compounds, e.g. an epoxy backing, to structurally reinforce the concaves and assist with contact between the radially outward facing surface of the concaves and the radially inward facing surface of the topshell or frame. In fact, the crushing forces must be transferred to the liners from the structural crusher parts which they protect, and for that, intimate contact is needed between the back of the liners and the surface of the topshell or frame.
The aforementioned wear parts are changed regularly, i.e. in intervals of 12, 18 or 24 months. The replacement is a relatively fast process for the mantle, which is usually replaced by swapping for a spare main shaft assembly. In contrast, the replacement of the concave liners is cumbersome. Typically, one unit per row - the so-called 'keystone' - is removed first so as to release any hoop stresses stored in the respective row of concaves. This is done by using a thermal lance to cut a valley in the concave which therefore allows it to be chiselled off with a rock breaker or other such hammer system. Once the 'keystone' is removed, the remaining concaves in the row are removed one by one along the circumferential direction. At that time, the epoxy backing still remains between the concaves and the supporting frame of the crusher and makes it difficult to remove the concave liners from the frame. Therefore, the concaves are removed one by one using a rock breaker, i.e. a hydraulic or pneumatic hammer which is driven behind the concaves at the top leading edge to break the epoxy backing.
In a large primary gyratory crusher, there can easily be 80 concaves to replace (four tiers (rows) with 20 segments per tier) . The existing methodology for the removal and replacement of concave liners - a process also known as a "re metal" - is very time consuming, often taking multiple days to complete. This equals downtime and lost production for the operator of the mine. As explained above, gyratory crushers are frequently used for first stage sizing in the minerals processing industry, so that any associated downtime can have serious consequences for downstream processing and therefore the overall plant productivity.
The removal of concaves is also a hazardous task requiring the use of hot works as well as the operation of a large rock breaker. Also, workers have to operate in the topshell area of the crusher, which - seeing as gyratory crushers can be up to ten storeys high - exposes them to risks related to working from heights.
Another issue with the existing methodology is the potential to damage the top shells (which are very expensive) during removal of the concave liners, thereby compromising the integrity of the crusher.
WO 01/28688 A1 relates to the replacement of wear liners for a gyratory crusher and suggest using a fixing and locating means between the housing of the crusher and a head liner.
WO 06/047681 A2 describes a bowl liner retaining device that allows for an easy and quick replacement of worn or unusable bowl liners on gyratory cone crushers.
Also known is a concave removal press sold by Tri Star Design. Said press attaches to the outside of the frame of the gyratory crusher and has a push rod extending into the crusher through a hole drilled into the frame in the area of the concave to be removed. The push rod is actuated by a hydraulic cylinder to push against the outer surface of the worn concave, thereby loosening the concave from the frame. This solution is still cumbersome, and a hole has to be drilled into the frame for each individual concave.
Summary of the invention
In view of the above, an object underlying the invention is to facilitate the removal of worn liner segments from a gyratory or cone crusher.
To achieve this object, the present invention provides a liner segment for a gyratory or cone crusher as recited in claim 1.
According to the invention, the liner segment is provided with an expandable ejector unit to be arranged between the outer surface of the liner segment and the opposite inner surface of the frame. The ejector unit has a first part for abutting or engaging with the outer surface of the liner segment and a
second part for abutting or engaging with the inner surface of the frame and is operable to increase a spacing between the first and second parts to thereby increase the spacing between the outer surface of the liner segment and the inner surface of the frame.
The ejector unit is mounted in its undeployed state between the rear or outer surface of the concave and the opposite, inner surface of the frame or topshell. In other words, the ejector unit is pre-installed between the rear surface of the concave and the opposite surface of the frame or topshell. If time has come for the concave to be removed, the ejector unit is operated to be expanded, prising the concave away from its support and breaking the epoxy backing.
The invention therefore removes the need for use of a hydraulic / pneumatic hammer to assist with the removal of the worn concave segments from a gyratory crusher and dispenses with the necessity to have workers operate immediately in the area of the concaves. This is a significant safety improvement over the existing methodology. The invention will also result in significant reduction in downtime during concave re-metal maintenance .
The invention will thereby result in an overall improvement in shutdown efficiency and effectiveness for all concave re-metal works .
Optional further features of the liner segment for a gyratory or cone crusher of the present invention are recited in the dependent claims.
The ejector unit may be expandable pneumatically or hydraulically. Also conceivable in principle are mechanically operable ejector units though, such as a high-powered spring released by remote control, or a servo-actuated lever arm.
The ejector unit may be operable to increase a volume of the ejector unit.
Specifically, the expandable ejector unit may include a lifting bag.
A lifting bag is capable of lifting loads of several tons, wherein a lifting bag with a capacity of e.g. six tons could be used for the purposes of the invention. The lifting bag is usually inflated with compressed air and in some cases with water or grout.
In comparison with other types of jacking equipment, lifting bags have major advantages such as the very small insertion height and fast operation. They are also light-weight and practically maintenance-free.
The lifting bag to be used according to the invention may be made from one or several layers per side. Suitable materials for the layer (s) include woven steel and Kevlar with neoprene. The surfaces of the lifting bags may be structured to provide an anti-slip effect.
The lifting bag functions according to the following principle: Force (F) = Pressure (P) x Area (A) . It is therefore advantageous to provide the lifting bag with a sufficiently large surface area to apply the desired force to the liner segment to be removed.
Suitable high-pressure inflatable lifting bags are available on the market, e.g. from MatJack Inc., for lifting, moving, spreading and fixing applications.
The liner segment may further comprise means for operating the ejector unit, e.g. including a hydraulic or pneumatic line or hose extending to each ejector unit in the crusher.
The liner segments may be configured to be arranged in at least one tier or row along the inner circumference of the frame of the crusher.
The ejector unit may be disposed in the area of a top edge of the liner segment. Compared to the case in which the ejector unit would be arranged in a central area of the liner segment, the removal of the liner segment is facilitated thereby: When activated, the ejector unit acts upon the upper portion of the liner segment to "peel" the liner segment away from the underlying support or frame.
The liner segment may be a concave liner as it is typically the case in gyratory or cone crushers.
A cavity or recess may be included in the outer surface of the liner segment to accommodate the expandable ejector unit. The recess acts as an ejector unit engagement portion. In other embodiments, the ejector unit could be installed between the rear or outer surface of the liner segment and the opposite surface of the frame without such a recess being formed in the back of the segment.
The invention also provides a gyratory or cone crusher as recited in claim 12, wherein a mantle and a bowl define a crushing gap between them, and wherein the bowl is constituted by a plurality of liner segments, with outer surfaces of the liner segments facing an inner surface of the frame. At least one of the liner segments is provided with an expandable ejector unit arranged between the outer surface of the liner segment and the opposite inner surface of the frame. The ejector unit has a first part for abutting or engaging with the outer surface of the liner segment and a second part for abutting or engaging with the inner surface of the frame and is operable to increase a spacing between the first and second parts to thereby increase the spacing between the outer surface of the liner segment and the inner surface of the frame .
The liner segment of the gyratory or cone crusher may include one or several of the features described above for the liner segment and ejector unit.
The gyratory or cone crusher may further comprise means for operating the ejector unit, e.g. including a hydraulic or pneumatic line or hose extending to each ejector unit in the crusher .
The liner segments of the gyratory or cone crusher may be arranged in at least one tier or row along the inner circumference of the frame.
At least one tier or row of the liner segments of the gyratory or cone crusher may be arranged so that several or even all liner segments in the row, preferably all liner segments but one in the row, are provided with an ejector unit.
One lifting bag could in principle be installed to act upon several (adjacent) concaves. A load distributor plate could then be provided so that the lifting bag is unaffected by any potential gap between the concaves or if one concave comes off before the other.
The ejector unit of the gyratory or cone crusher may be disposed in the area of a top edge of the liner segment.
The liner segments of the gyratory or cone crusher may be concave liners.
In the gyratory or cone crusher, a backing such as an epoxy backing may be disposed between the outer surface of the liner segment and the inner surface of the frame to integrate the ejector unit with the liner segment and the support.
The gyratory or cone crusher may further be associated with a control unit to control the activation of the ejector unit(s),
e.g. from a remote location, e.g. by way of a wireless connection .
The present invention further provides a method of dismounting at least one liner segment from a gyratory or cone crusher as recited in claim 18. The method includes the steps of arranging an expandable ejector unit between the outer surface of the liner segment and the opposite inner surface of the frame, the ejector unit having a first part abutting or engaging with the outer surface of the liner segment and a second part abutting or engaging with the inner surface of the frame, and operating the ejector unit to increase a spacing between the first and second part to thereby increase the spacing between the outer surface of the liner segment and the inner surface of the frame.
If the liner segments are arranged in at least one tier or row along the inner circumference of the frame of the crusher, one keystone liner segment in each of the tiers or rows may be removed, e.g. with the aid of a thermal lance, to release any hoop stresses prior to activating the ejector unit(s) in said row .
The ejector units for the individual segments in a tier or row could be activated one after the other so as to dismount the segments one after the other along the circumference of the crusher; or several ejector units could be activated simultaneously to dismount several, possibly several adjacent, liner segments simultaneously.
If several rows of liners are provided, as it is usually the case in gyratory crushers, the removal of the rows of segments would start with the uppermost row of segments in the crusher .
Upon completion of the dismounting of one row of segments, the dismounted liner segments can then be removed from the crusher in any known manner. For example, a removal tray or bin may be
positioned below the row of liner segments being ejected, and an entire tier or row of segments may be lifted out of the crusher at the same time.
The invention covers the use of an expandable ejector unit such as a lifting bag to dismount a liner segment from a gyratory or cone crusher, as recited in claim 21.
Finally, the present invention also relates to a liner segment for a gyratory or cone crusher as recited in claim 22. The liner segment of claim 22 comprises an ejector unit engagement portion configured to receive or accommodate an expandable ejector unit.
The liner segment of claim 22, and the expandable ejector unit which it is configured to receive or accommodate, may comprise any of the aforementioned features or combinations thereof.
Also, the ejector unit engagement portion could for example be a recess or cavity in the outer surface of the liner segment to accommodate the expandable ejector unit. The recess or cavity could have a temporary, easy to remove, material inserted therein during installation. When it is time to install the ejector unit, this insert could be removed or destroyed in place to make room for the ejector unit.
The shape of the recess in the liner segment can be designed to match the shape of the ejector unit, e.g. the lifting bag. The matching shapes may provide for a form-fit between the ejector unit and the liner segment.
Brief description of the drawings
The above, as well as additional objects, features and advantages of the present invention will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention,
with reference to the appended drawings, where the same reference numerals will be used for similar elements, wherein:
Figures la and lb schematically illustrate a part of a frame of a gyratory crusher equipped with liner segments in accordance with the present invention, from two perspectives;
Figure 2a illustrates one of the liner segments of Figure 1;
Figure 2b shows a lifting bag in a deflated state;
Figures 3a and 3b illustrate the liner segment with the lifting bag in a perspective view and from the side;
Figures 4a and 4b illustrate the liner segment, again in a perspective view and from the side, with the lifting bag after inflation;
Figure 4c shows the lifting bag in the inflated state;
Figures 5a and 5b are partial views, from the side and in perspective, of the liner segment and crusher frame with the inflated lifting bag; and
Fig. 6 shows schematically a gyratory crusher of the prior art.
Detailed description of a preferred embodiment
Fig. 6 schematically illustrates a previously known gyratory crusher 100 in section.
The sole purpose of this illustration is to explain the basic operating principle of a gyratory or cone crusher, and it is not to be understood to imply any limitation of the present invention .
The gyratory crusher 100 has a vertically extending main shaft 102 and a frame 104. The shaft 102 has a longitudinal axis
coinciding with a central axis A of the crusher. Other than most gyratory crushers which have their main shaft suspended from a spider bearing, the one illustrated here is spider-less The crusher includes an eccentric assembly which in this previously known embodiment is provided in the form of two eccentric rings 106, 108 rotatably supported about the shaft
102. A crusher head 110 is radially supported by and rotatable about the eccentric rings 106, 108.
A drive shaft 112 is connected to a drive motor and is provided with a pinion 114. The drive shaft 112 is arranged to rotate the lower eccentric ring 108 by the pinion 114 engaging a gear rim 116 mounted on the lower eccentric ring 108. When the drive shaft 112 rotates the lower eccentric ring 108, the crusher head 110 executes a gyrating movement.
An inner crushing shell 118, also designated a mantle, is mounted on the crusher head 110. Crusher head 110 and mantle 118 are parts of an overall head assembly. An outer crushing shell 120, also designated a bowl, is mounted on the frame 104 A crushing gap 122 is formed between the two crushing shells 118, 120. When the crusher 100 is operated, material to be crushed is introduced in the crushing gap 122 and is crushed between the mantle 118 and the bowl 120 as a result of the gyrating movement of the crusher head 110, during which movement the mantle 118 approaches the bowl 120 along a rotating generatrix and moves away therefrom along a diametrically opposed generatrix.
Figure 1 schematically illustrates a part of a bowl of a gyratory crusher which is constructed in accordance with the present invention. The bowl is constituted by a plurality of liner segments 30, with outer surfaces of the liner segments 30 facing an inner circumferential surface of a frame 40 of the crusher which is substantially annular. The liner segments 30 are configured to be arranged in at least one tier or row along the inner circumference of the frame 40 of the crusher. In the present case, the liner segments are provided in the
form of concave liners, also designated concaves. The expressions "concaves", "liners" and "segments" may therefore be used interchangeably to designate the liner segments.
In the operational state of the crusher, an epoxy backing (not specifically illustrated) would be poured into the remaining gap between the outer surfaces of the liner segments 30 and the facing inner circumferential surface of the frame 40. The epoxy backing is, in a manner known per se, provided to structurally reinforce the concaves 30 and assist with contact between the radially outward facing surfaces of the concaves 30 and the radially inward facing surfaces of the frame 40. The backing material fills the void between the concaves 30 and the frame 40 to provide a solid assembly. In a crusher according to the invention, the epoxy backing also integrates the lifting bag 50 with the liner segment 30 and the frame 40. Lead, zinc, babbit metal and other materials have been used as alternatives to epoxy resin.
To facilitate the removal of the liner segments 30 from the frame or topshell 40 and exchange against new liner segments, the liner segments 30 are each provided with an expandable ejector unit 50 arranged between the outer surface of the liner segment 30 and the opposite inner surface of the frame 40. The ejector unit is expandable so as to increase the spacing between the outer surface of the liner segment 30 and the inner surface of the frame 40. The ejector unit is mounted in its undeployed state between the rear surface of the concave and the opposite surface of the frame 40. In other words, the ejector unit is pre-installed between the rear surface of the concave liner segment 30 and the opposite surface of the frame or topshell 40. If time has come for the concave 30 to be removed, the ejector unit is operated to be expanded, prising the concave 30 away from its support and breaking the epoxy backing.
The invention therefore removes the need for use of a hydraulic / pneumatic hammer to assist with the removal of the
worn concave segments from a gyratory or cone crusher and avoids the need for workers being present in the area of the concaves proper. This is a significant safety improvement over the existing methodology on the one hand and will also result in significant reduction in downtime during concave re-metal maintenance on the other hand.
The invention encompasses ejector units which are expandable in different ways, e.g. pneumatically or hydraulically. One practical implementation of the expandable ejector unit, which is also used in the embodiment shown in Figures 1 through 5, is an inflatable lifting bag 50. The lifting bag 50 is arranged between the outer surface of the liner segment 30 and the opposite inner surface of the frame 40 of the crusher. The lifting bag 50 has opposite main surfaces, a first one abutting or engaging with the outer surface of the liner segment 30 and a second one abutting or engaging with the inner surface of the frame 40. The lifting bag 50 is installed in its deflated state. When the lifting bag 50 is operated to be inflated, the volume of the lifting bag 50 increases, and the spacing between the first and second surfaces is enlarged to thereby push the liner segment 30 away from the inner surface of the frame 40, breaking the epoxy backing and dismounting the liner segment 30 from the frame 40.
Each of the liner segments 30 illustrated in Figure 1 is provided with a lifting bag 50. In one practical embodiment, each liner segment 30 but one in the row of liner segments 30 would be provided with an expandable ejector unit for reasons set forth further below.
In the present embodiment, each lifting bag 50 is associated with one liner segment 30. In principle it is conceivable to associate a lifting bag 50 with several, i.e. two, three or even more, adjacent liner segments 30 which would then be acted upon simultaneously.
In the illustrated embodiment, the lifting bag 50 is disposed in the area of a top edge of the respective liner segment 30. Compared to the case in which the lifting bag 50 would be arranged in a central area of the liner segment 30, the removal of the liner segment 30 is facilitated thereby: When inflated, the lifting bag 50 then acts upon the upper portion of the liner segment 30 to "peel" the liner segment 30 away from the underlying support or frame 40.
Figure 2a shows a liner segment 30 of the embodiment of Figure 1 without a lifting bag 50. The concave liner 30 of this embodiment is distinguished from similar concaves of the prior art in that a cavity or recess 60 is included in the back of the liner segment 30 which is large enough to accommodate the deflated lifting bag 30 when the liner segment 30 is mounted to the crusher.
Illustrated in Figure 2b is one exemplary implementation of a lifting bag which is available under the trade name "MatJack" for lifting, moving, spreading and fixing applications. The lifting bag is capable of lifting a predetermined weight such as e.g. 6 tons if inflated with air under a corresponding pressure. In the present embodiment, the lifting bag has an approximately square shape, but a lifting bag for use in the invention could as well have other shapes such as rectangular or round.
The lifting bag 50 and the recess 60 in the liner segment 30 have matching shapes, e.g. to provide for a form-fit between the lifting bag 50 and the liner segment 30. In the present embodiment, the lifting bag 50 has four tabs 51 integrally molded to the edges thereof for lifting or attaching to fixtures. In the present embodiment, the recess 60 in the back of the liner segment 30 includes corresponding cut-outs 61.
In other embodiments, the lifting bag 50 could be installed between the rear surface of the concave 30 and the opposite
surface of the frame 40 without such a recess 60 being formed in the back of the concave 30.
The lifting bag 50 functions according to the following principle: Force (F) = Pressure (P) x Area (A) . The surface area of the lifting bag 50 should therefore be sufficiently large to create the desired force. The surface area of the lifting bag 50 should suitably amount to a sufficient percentage of the surface area of the concave 30, i.e. the surface area of the rear or outer surface of the concave as shown in Figure 2a. In the illustrated embodiment, the surface area of the lifting bag 50 could amount to about one quarter of the surface area of the rear or outer surface of the concave 30, to give an example.
Figures 3a and 3b illustrate the liner segment or concave 30, in a perspective view and from the side, with the lifting bag 50 installed in the aforementioned recess 60. Figures 4a and 4b illustrate the liner segment 30, again in a perspective view and from the side, with the lifting bag 50 after inflation. Also shown is the exemplary lifting bag 50 in the inflated state (Figure 4c) . Figures 5a and 5b are partial views from the side and in perspective of the liner segment 30 and the crusher frame 40 in a state in which the lifting bag 50 between the outer surface of the concave 30 and the inner surface of the frame 40 has been inflated and has separated the concave 30 from the frame 40.
For operating the ejector units, i.e. lifting bags 50, a pneumatic line or hose (not shown) extends from each lifting bag in the crusher towards a source of compressed air (not shown) . The lifting bags 50 in Figures 2b and 3c include a corresponding connector 52 for a pneumatic line. The pneumatic lines from several lifting bags 50 could be combined via corresponding manifolds. A control unit (not shown) such as push button, deadman or joy stick controller is provided to control the supply of compressed air to independently or simultaneously inflate one or more of the lifting bags 50.
Considering the gyratory or cone crusher as a whole, several liner segments in each tier or row are provided with an ejector unit. In one implementation, all liner segments but one in each tier or row are provided with an ejector unit. The remaining segment in each row is the "keystone" segment which, as in conventional methods, is removed with the help of a thermal lance so as to release any hoop stresses before the remaining concaves 30 are dismounted by activating the ejector units such as lifting bags 50. This sequence of steps is typically performed starting with the uppermost row of segments 30 in the crusher.
The lifting bags 50 for the individual segments 30 in a tier or row can in principle be activated one after the other so as to dismount the segments 30 one after the other along the circumference of the crusher similar as in the prior art. One could also consider activating several lifting bags 50 simultaneously to dismount several, possibly several adjacent, liner segments 30 simultaneously. Anyhow, the process is continued until all segments 30 in a circumferential row are dismounted and ready to be removed from the crusher.
The dismounted liner segments 30 are then removed from the crusher in any known manner. For example, a removal tray or bin (not shown) could be positioned below the row of liner segments being ejected, and an entire tier or row of segments could be lifted out of the crusher at the same time.
The invention will result in an overall improvement in shutdown efficiency and effectiveness for all concave re-metal works .
While one embodiment of the invention has been described with reference to Figures 1 to 5, the scope of the invention is not restricted to this embodiment but defined by the appended claims. Various modifications are included within the scope.
For example, the principle of the present invention, i.e. the use of an expandable ejector unit to dismount a liner segment from the underlying crusher frame, could also work with so- called double-tier concave segments: The double-tier concave segments are twice as high as regular liner segments. This translates to 50% fewer consumable parts to be changed, and ultimately reduces exposure to risks for the crews performing the re-metal .