WO2020037440A1 - Lifters for use in comminution devices in industrial and mining works - Google Patents

Abstract

The present invention relates to comminution devices in industrial and mining works, particularly to lifters, the combination of the design and/or materials thereof allowing, altogether, the stoppage time for equipment maintenance to be reduced, owing to easier assembly and disassembly of these products in a mill, and the total number of lifters used in the liner assembly to be reduced, as well as maintaining the feasibility of recycling the conventional pieces.

Description

 LIFTERS FOR USE IN CONTROLLER EQUIPMENT

 IN INDUSTRIAL AND MINING FAULES

 Technical Field

 [001] The present invention relates to equipment with induction in industrial and mining operations. Particularly, the present invention relates to equipment coatings (known in the technical area as lifters and referred to hereinafter simply as lifters) which, in addition to protecting their structure, are used as load lifters during the production process and whose technical advantages They allow, among other things, to reduce both the total weight and the number of parts that make up the set of coatings of said equipment, also achieving a significant decrease in maintenance times thanks to the optimization of assembly and disassembly times, maintaining and / or improving the shelf life of the product.

 [002] In parallel, it is important to note that the present invention allows to maintain the recycling capacity of the lifters and grants cost benefits compared to the lifters of the prior art.

Previous Art

 [003] Comminution equipment, such as autogenous or semi-autogenous mills, balls and bars, decreases the size of the material that enters them through the impact and / or abrasion that is generated thanks to its constant rotation. These teams rotate around its axis, generating, in this way, the permanent rubbing and impact between the different components of its load (mainly mineral and steel balls).

 [004] For their operation, these equipments are provided with an inner lining that, in addition to protecting their structure, is responsible for optimizing the drag, impact and movement of the load in process, thereby efficiently reducing its size.

 [005] In particular, part of the inner lining of these comminution equipment corresponds to lifters. Its function during the operation of the mill is to raise the material through its internal walls to the point where gravity manages to separate it from the wall and, as in the case of semi-autogenous mills, propel this material in a parabolic fall in the direction of the lower part of the mill where the rest of the load that is being processed is located, producing, in this way, the necessary impact for the reduction of the size of the treated material.

[006] Currently, the set of coatings constitutes an important part of the weight that the mill rests bear, this being one of the reasons that limit the material processing capacity. In addition, the greater the weight, the more energy consumption is generated during the operation and, to the extent that said set of Coatings are made up of a larger number of pieces, increasing the time required for each maintenance that considers its renewal.

 [007] Coatings of different materials exist in the industry: cast steel, steel-rubber (rubber with steel inserts inside) and 100% rubber. However, none of the documents of the prior art teach or suggest that there is any proposal as described in this application.

 [008] For example, in the application WO 2011/130781 on behalf of Vulco SA et al., Wear plates are described as part of the lining of a mill, which comprise an elastomer body, where various grooves and holes are arranged of material discharge. In this application an elastomeric block is particularly disclosed which is cast by casting on a support plate and contains a series of discharge holes. The technical problem that solves the invention described in said document is related to minimizing the repeated obstruction of the discharge holes of the equipment.

 [009] In US Patent 4,177,955 (The BF Goodrich Company), the problem generated by the use of metal lifters between rubber liners, particularly related to the high torque generated between steel lifters and adjacent cladding parts of Rubber. In this document, a rubber coating laterally bonded to a rigid plastic portion, such as high molecular weight polyethylene, is proposed as a solution. With this solution it is possible to obtain a light and adaptable coating to be arranged between the metal lifters and, therefore, does not replace them or modify their structure.

 [0010] On the other hand, US Patent 9,475,057 (Cabot Corporation) addresses the problem of minimizing the frequency at which mill liners must be replaced, for which lifters are proposed which include an upper elastomeric layer and a lower elastomeric layer. , of different composition each.

 [0011] The inventors have not detected publications that disclose technical solutions whereby the production of a comminution equipment is optimized by optimizing the weight of their steel coatings and minimizing their replacement time, as the solution delivered by the present invention.

Summary of the Invention

 [0012] An objective of the present invention is to provide steel lifters for comminution equipment such as semi-autogenous, ball mills or the like, lighter than those currently used.

[0013] It is yet another objective of the present invention to reduce the replacement time of the lifters, thus decreasing the maintenance time of the comminution equipment and, therefore, increasing the availability thereof. [0014] It is another objective of the present invention to reduce the total number of lifters used in the comminution equipment since the optimization of the individual weight compared to that of the lifters currently used in the art, allows to increase its size and, therefore, therefore, decrease the total number of pieces of the cladding set.

 [0015] It is another objective of the present invention to at least maintain the performance of the lifters with respect to those of the prior art.

 [0016] Additionally, it is another objective of the present invention not to alter the feasibility of recycling the lifters once their useful life in the operation of the comminution equipment has been fulfilled. The foregoing is possible, thanks to the geometry of the product and the characteristics of the rubber application in any of the embodiments of the present invention.

 [0017] In view of the technical advantages achieved by the present invention, it should be understood as a global objective to increase production through increased availability.

 [0018] These and other objectives, as well as the technical advantages associated with the present invention will be apparent to the expert from the following description.

Brief description of the figures

 [0019] The invention will be described in an exemplary manner and in reference to the attached drawings, wherein:

 [0020] Figure 1 shows a coating mantle section for comminution equipment with prior art lifters, typically employed in the industry.

 [0021] Figure 2 is a cross-sectional view of a prior art lifter.

 [0022] Figure 3 shows a set of lifters according to an embodiment of the present invention, as they would be arranged in a comminution equipment. The expert will understand that this assembly forms a portion of the liner of lifters that are arranged in a comminution equipment.

 [0023] Figure 4 is a top perspective view of a lifter according to an embodiment of the present invention.

 [0024] Figure 5 is a bottom perspective view of a lifter according to an embodiment of the present invention, where the portion of steel with cavities in its lower face is shown.

[0025] Figure 6 is a bottom perspective view of a lifter according to another embodiment of the present invention, where the rubber-coated steel portion is appreciated. [0026] Figure 7a illustrates the cross section of lifters in accordance with an exemplary embodiment of the present invention.

 [0027] Figure 7b illustrates the cross section of a lifter according to another exemplary embodiment of the present invention.

 [0028] Figure 7c illustrates the cross section of lifters in accordance with yet another exemplary embodiment of the present invention.

 [0029] Figure 8a shows results of wear profiles in a cross-section of a lifter according to an exemplary embodiment of the present invention, described in Example 1; where the black lines show the nominal profile, and the red lines show the wear profile.

 [0030] Figure 8b shows results of wear profiles in a cross-section of a prior art lifter, according to what is discussed in Example 1; where the black lines show the nominal profile, and the red lines show the wear profile.

Detailed description of preferred embodiments of the present invention

 [0031] As can be seen in Figure 1, comminution equipment such as Semiautogen (SAG) mills, autogenous, ball mills, or others, employ different types of coatings to fulfill the task of reducing the load size processed. Lifters are among the types of siding typically used in these comminution equipment. These lifters are usually made of steel, rubber or hybrids. Its main function is to allow the material to be processed to be lifted during the operation of the comminution equipment so that, once above, due to gravity, they are separated from the wall of the mill and fall towards the lower section of the mill. In this way, through the impact and abrasion generated, allow the comminution of the material, that is, the decrease in its size.

 [0032] In accordance with one aspect of the present invention, lifters (1) are provided for use in comminution equipment, whose main body (2) is cast steel, preferably chrome-molybdenum alloy, white iron, or other. In preferred embodiments, these pieces have reinforcements (3) of rubber or other polymer, which can cover at least a portion of the steel body, such as side walls and / or base.

[0033] The steel part or body (2) has, on its upper face (21), at least one shoulder or protuberance (212), while on its lower face (22) it has at least one cavity (223), as can be seen, for example, in Figure 5. This at least one cavity (223) covers between about 1% and about 30% of the total volume of the lifter. In preferred embodiments, the at least one cavity may range between about 3% and about 20% or between about 5% and about 15% of the total volume of the lifter. It should be understood that other combinations of percentages are possible within the ranges already described, and that multiple cavities may exist as long as the range of defined percentages is maintained.

 [0034] The presence of this at least one cavity (223) makes it possible to reduce the total volume and weight of the steel piece, without damaging its mechanical strength, thus achieving, at least, the same lifespan and the same functionality of the lifters of prior art. This is not trivial, precisely because the at least one cavity decreases the volume of the lifter and, therefore, the expert would expect a noticeable decrease in the mechanical strength of the piece. Moreover, depending on the location of the at least one cavity (223) on the lower face of the main steel body, with respect to the at least one protuberance (212), it would be expected that the constant impact of the material with the lifter, damage its structure in advance, affecting its useful life.

 [0035] Notwithstanding the foregoing, and surprisingly, the present invention allows at least maintaining the lifespan of the lifters, and at least maintaining their function, when compared with lifters employed in the art, with the consequent benefits that this implies and that have been described in an exemplary way, in the synthesis of the invention.

 [0036] The at least one cavity (223) of the steel part can be of any geometry, such as a square, rectangular, rounded, circular or ovoid base; or of square, rectangular, rounded, concave, ovoid, sinusoidal section, or a combination of them. The expert will understand that other forms are possible, without departing from the scope of what is described here.

 [0037] As for the at least one protuberance (212) of the main body (2) of steel, it can be convex in at least a portion of the body (2) or flat in at least a portion of the body (2). In a preferred embodiment, the at least one protuberance (212) is convex in at least a longitudinal portion of the main body (2). In yet another preferred embodiment, the at least one protuberance (212) of the main steel body is convex along the entire longitudinal axis of the main steel body (2). The basal ends of the at least one convex protuberance may be straight or curved, forming in some embodiments concave portions on the upper face of the main body, or a cross section of a general sinusoidal shape. Other combinations of the geometries described in this paragraph are also possible, without departing from the scope of the invention.

[0038] As regards the reinforcement (3) of rubber or other polymer, this may be of any type of rubber or polymer, but preferably it is an abrasion resistant rubber. In a preferred embodiment, it is arranged in the lateral areas and / or at the base of the lifter (1). For example, the rubber coating (3) can cover at least one side face of the steel part, such as a pair of side faces; and in still another preferred embodiment, it can cover the base of the steel part, including, for example, the area where the emptying is located.

 [0039] The joining of the steel and rubber parts is carried out by means of a hot or cold vulcanizing system, thus obtaining a resistant union that prevents the rubber from losing grip when receiving impacts or suffering from rubbing or contact with others. elements both in its transfer and in its installation.

 [0040] The final form of the lifters of the present invention can vary significantly, depending on their position in the comminution equipment, or the typical industry requirements for the optimization of the comminution equipment production, because the Advantages of the invention result, among others, from the particular combination of elements that allow, on the one hand, to reduce the weight of the piece and, on the other, at least maintain the performance of the lifters with respect to lifters of the prior art.

Application examples

 [0041] An example of one of the preferred embodiments of the present invention is presented below. It should be understood that, as such, the example set forth here shows particular conditions of use of one of the preferred modalities, implemented in a mining operation. In no case should they be considered as a limiting or restrictive example of the present invention.

 Example 1

 [0042] In a mineral extraction mining site, lifters of the present invention were installed as part of the interior lining of a 40 x 26-foot SAG mill (12.19 m by 7.92 m). The lifter used was of the type of piece formed by molybdenum chrome alloy cast steel, where the steel structure had on its underside a series of 3 cavities that, together, covered 15% of the total volume of the lifter.

 [0043] The steel part had side and bottom coatings of hot vulcanized rubber, 30 mm and 6 mm thick, respectively.

 [0044] Once the installation of the lifters was completed, the mill was started, which was operational for 182 days and 13.7 million tons processed before maintenance was required to replace parts.

[0045] At the end of this period, control measurements were made whose results can be seen in Figures 8a and 8b and in Table 1:

 TABLE 1: Shows the data related to the lifter and plate wear of the present example, as illustrated in Figure 8a and the lifter and plate wear of a prior art lifter, illustrated in Figure 8b, he who had no cavity.

 [0046] As can be seen, with the lifters of the present invention a better wear performance is obtained than that obtained with coatings employing lifters of the prior art. In addition, it was verified that the change time (Disassembly / Assembly) was less than or equal to the change time of previous art lifters.

 [0047] Although the present invention has been described and exemplified in reference to the preferred embodiments, it should be understood that there are variations and changes that can be made without departing from the scope of the claimed invention, which will be apparent to the expert.

 * **

Claims

1. A lifter for use as an inner lining element in comminution equipment, characterized in that it is composed of a main body of cast steel, where the main body of steel has, on its upper face, at least one protuberance and on its face bottom with at least one cavity, where the at least one cavity covers between 1% and 30% of the total volume of the lifter.  2. The lifter of claims 1, characterized in that the at least one cavity comprises between 3% and 20% of the total volume of the lifter.  3. The lifter of claims 1 or 2, characterized in that the at least one cavity comprises between 5% and 15% of the total volume of the lifter.  4. The lifter of any of the preceding claims, characterized in that the main body of cast steel has a polymeric coating that comprises at least a portion of the main body of steel.  5. The lifter of claim 4, characterized in that the polymeric coating comprising at least a portion of the main body of steel is rubber or another polymer that guarantees the correct performance of the product in the application.  6. The lifter of claim 4 or 5, characterized in that the at least a portion of the main steel body is one of its lateral faces.  7. The lifter of claim 4 or 5, characterized in that the at least a portion of the main steel body corresponds to both side faces of the main body. 8. The lifter of claim 4 or 5, characterized in that the at least a portion of the main steel body is its lower face or base.  9. The lifter of claim 8, characterized in that the at least a portion of the main body includes the at least one cavity partially or totally.  10. The lifter of any of the preceding claims, characterized in that the at least one cavity of the steel body is square, rectangular, rounded, circular or ovoid, or a combination thereof.  11. The lifter of any of the preceding claims, characterized in that the at least one cavity of the steel body is square, rectangular, rounded, concave, ovoid, sinusoidal, or a combination thereof. 12. The lifter of any of the preceding claims, characterized in that the at least one protuberance of the main body of steel is convex in at least a portion of the longitudinal axis of the main body. 13. The lifter of claim 12, characterized in that the at least one protuberance of the main steel body is convex along the entire longitudinal axis of the main body.  14. The lifter of any of the preceding claims, characterized in that the at least one protrusion of the main leather is flat on at least a portion of the longitudinal axis of the main body.  15. The lifter of any of the preceding claims, characterized in that the basal ends of the at least one protrusion of the main steel body are straight.  16. The lifter of any one of claims 1 to 13, characterized in that the basal ends of the at least one protrusion of the main steel body are curved.  17. The lifter of any one of claims 1 to 13, characterized in that at least one basal end of the at least one protuberance of the main steel body has one or more concave portions in the upper front face of the main body.  18. The lifter of any one of claims 1 to 13, characterized in that at least one basal end of the at least one protrusion of the main steel body is of sinusoidal general cross-section.  19. The lifter according to any of the preceding claims, characterized in that the steel of the main body is molybdenum molybdenum steel, white iron or another family of alloys.