UA115986U - DRUM MILL LINE - Google Patents

Abstract

The lining of the drum mill contains flat elastomeric plates and elevators with alternating working and non-working surfaces, the working surface of elastomeric plates is made of a combination and includes a projecting surface of wear-resistant ball inserts, and the elevators are made in the form of straight bars, the work of which includes lateral surfaces. The lateral working surface of the lifter towards the grinding mass is made with a bevel. The elastomeric plates are made with recesses, into which the balls are pressed and held in them due to the elastic characteristics of the material of the plates and stiffeners, which are made along the transverse contour at the level below the upper edge of the niche, and the working surface of the elevators is made smooth.

Description

The useful model belongs to the equipment for grinding solid materials and can be used in the mining and beneficiation industry at the final stages of grinding ores, chemical and energy industries, in the production of ceramic products, when grinding non-metallic materials.

The use of drum mills, in particular in the ceramic industry and at the final stage of ore grinding, is special in that it is necessary to obtain finely ground highly dispersed material or a homogeneous mixture of materials. This can be achieved only by the method of material abrasion in a dense moving mass of grinding bodies, such as balls. At the same time, not only the material in the drum of the mill is ground, but also the lining of the drum, grinding bodies... The design and material of the lining, the resistance of the lining to wear, the ability of the lining to keep the shape of the working surface throughout the entire period of operation determine the productivity of the drum mill.

For the production of linings of drum mills, such elastic materials as rubber, polyurethane, and other polymers are used, which makes it possible to increase the productivity of drum mills and increase the service life of linings. At the same time, the working surface of the liners must be resistant to abrasive wear and corrosion as a result of the impact of the grinding mass, which consists of grinding balls and pulp that is crushed. To further increase the resistance to abrasive wear of linings made of elastomeric materials, various methods of protecting the working surface of the linings are proposed by placing on it separate hard bodies, the hardness and wear resistance of which is equal to or higher than the hardness and wear resistance of grinding bodies.

Different designs of elastomer linings are known, on the working surface of which solid bodies of different shapes are placed, with different methods of fixing in the elastic material of the linings. Such linings combine the high wear resistance of hard elements and the ability to absorb the energy of shock loads of elastomer. Solid elements of combined liners are made of cast iron, special steels, wear-resistant ceramics. At the same time, it is necessary to ensure reliable fastening of solid elements in the elastomeric material.

There is a well-known lining of a ball mill, which contains sections made of elastic material from a set of inserts of different heights, which form a stepped working surface. The inserts are made of elastic material - rubber, on the working surface of each insert are longitudinal

From recesses located at an angle of 35-45" to the axis of rotation of the mill with the dimensions of the recesses in height equal to 2-3 maximum diameters of the grinding balls and a width of 0.8-0.9 of the diameter of the grinding balls. The balls get stuck in the recesses during the rotation of the mill , parts of the surface of the balls protrude above the working surface of the liners, which increases the wear resistance of the liners (invention patent KO 2038146, МПК ВО2С17/22, publ. 06.27.1995).

The disadvantage of such a lining is the large depth of recesses and the height of the liners, which leads to a significant thickness of the liner and a large volume of the lining set as a whole. As a result, the working volume of the mill decreases and its productivity decreases.

A known rubber-ceramic composition containing a rubber layer with niches in which ceramic bodies are fixed close to each other. The shape of the ceramic bodies is chosen mainly with a quadrangular or triangular profile, although a hexagonal profile or even spheres can be used. Ceramic bodies are obtained by sintering material based on aluminum oxide.

To ensure the strength of the connection, a thin connecting layer, for example, made of epoxy resin, is provided between the inner surface of the niches and the ceramic bodies. At the same time, the total area of the ceramic surface is ensured to be maximum and can approach 100 percent (invention patent 05 3607606, IPC B3285/16, B32825/02, B32815/06, publ. 09/21/1971).

The disadvantage of such a composition is the complex manufacturing technology, which does not ensure sufficient reliability of fastening. In case of separation of at least one ceramic body from the rubber base, the whole element quickly fails, since the formed shell in the rubber massif is the center of accelerated wear of the lining under the action of the grinding mass of the mill. In addition, flat products obtained by pressing and sintering from aluminum oxide have non-uniform properties and insufficient resistance to bending stresses, which reduces the reliability of the lining.

A wear-resistant lining for ball mills is known, which contains elastic segments of geometrically regular shape with recesses for placing solid bodies in them, in each recess at least one solid body is placed, while the shape of the recess is determined by the spherical part of the spherical segment and has the profile of a hemisphere or a cylinder, and its the depth is not less than the radius of the corresponding sphere. In particular, ceramic and metal elements are used as solid bodies (European application for an invention, publication

MeER2674220, IPC VO2C17/22, publ. December 18, 2013).

The disadvantage of such a lining is that the smooth walls of a small recess cannot ensure reliable fixation of a solid body or solid bodies in the recess, especially under conditions of shock loads. Round solid bodies, which are the most common grinding bodies, "twist" from their positions under the action of the grinding mass that slides over them, leave recesses, as a result of which the working surface of the liner loses its integrity. In addition, this design of the liner, which contains only plates of the same height, reduces the productivity of the mill, since there are no vertical movements in the layers of ball loading close to the surface of the liner.

A lining for ball mills is known, which contains plates of the same height, in the surface of which balls are fixed, which partially protrude above the working surface of the plates. Hard balls are fixed in polymer plastic with the help of depressions, protrusions, grooves on the surface of the balls. In this case, the balls of the lining plates have different diameters, the balls with a smaller diameter are placed between the balls with a larger diameter (patent for the invention MeOE 19847920, MPK VO2S 17/22, publ. 04.20.2000).

As in the previous case, with this design of the lining, there are no vertical movements of the ball loading. In addition, the use of balls of a non-standard configuration makes the use of such liners more expensive.

A wear-resistant lining for ball mills is known, containing plates of the same height with recesses arranged in a certain geometrical order to accommodate the solids.

At least one solid body is placed in each recess, and the shape of the recess is determined by the shape of the solid body. The recesses along the upper contour are equipped with ridges or ribs that ensure solid bodies are fixed in the recesses. The solid body is fixed in the matrix by connecting materials, in particular by means of glue and/or vulcanization. The depth of the recess is chosen so that at least part of the solid body protrudes above the working surface of the lining (European application for the invention, publication

MeER2674221, IPC VO2S17/22, publ. 18.12.2013).

The disadvantage of such lining is that only horizontal movement of grinding mass occurs on the working surface of the lining. Placement of protrusions along the upper contour of the recess, on its face with the working surface of the slab, gives a short-term effect of securing solid bodies in the recess, as such protrusions quickly wear out and solid bodies "jump out" of the recesses.

The lining of a drum mill, which contains only plates, is considered the closest analogue

A combination of plates and lifters, while the lifters can be autonomous elements or their role can be performed by a part of the plate. Hard bodies made of steel or cast iron, whose hardness is equal to or greater than the hardness of the loading balls and which have the shape of a ball and protrude outward relative to the surface of the lining to a height of less than half the diameter of the ball, are embedded in the working surface of plates and lifters. Solid bodies, fixed in the mass of the lining by the method of vulcanization at the stage of plate production, prevent the sliding of the mill loading on the surface of the lining, protect against bullet impacts and increase the resistance of the lining to wear, increase its service life (international application for the invention, international publication UMO 93/25310, IPC VO2S 17/22, published on December 23, 1993). The disadvantage of the specified design of the lining is the complex process of its manufacture, which includes preparing the surface of the balls for attachment to the elastic substrate, placing and fixing them in the press form of the complex surface. Lining plates with balls fixed in them have a large mass, which complicates their installation.

The spherical parts of the balls protruding from the lifters inhibit the downward movement of the balls and increase the point of their separation from the liner. As a result, the density of the flow of falling balls decreases, the intensity of the grinding process decreases. In addition, in the grinding process of a number of materials, for example, in the manufacture of ceramics, the use of metal balls is unacceptable, therefore traces of metal wear contaminate the finished product.

The task of a useful model is to create a combined lining with a self-healing working surface while simultaneously ensuring grinding in a stable cascade mode, which would ensure an increase in the productivity of a drum mill at the final stages of grinding ores, in the chemical and energy industry, in the production of ceramic products, when grinding and preparing mixtures of non-mineral materials

The task is solved by the fact that the lining contains flat elastomeric plates and lifters with a working and non-working surface, which alternate with each other, the working surface of the elastomeric plates is combined and includes a protruding surface of wear-resistant ball inserts, and the lifters are made in the form of straight bars, the working surface which includes the upper and side surfaces, while the lateral working surface of the lifter towards the grinding mass is made with a bevel, according to the useful model, the elastomeric plates are made with niches into which the balls are pressed and held in them due to the elastic characteristics of the material of the plates and stiffeners, which made along the transverse contour at a level below the upper edge of the niche, because the working surface of the lifters is made smooth.

Unlike the closest analogue, the useful model does not have an integral connection of the ball inserts with the plate. Before starting the mill, the drum is equipped with elastomeric plates with niches and elastomeric lifters. Wear-resistant balls are pressed into the niche of the plate during the rotation of the drum of the mill with grinding bodies without feeding the material to be crushed. Protruding parts of the spherical surface of the balls create an obstacle to the movement of the pulp flow, increase the density of the particles of the material that is crushed near the surface of the liner, in the space between the protrusions of the balls, which also prevents the sliding of the grinding balls, the loading mass on the surface of the liner. Eliminating the sliding of the load on the surface of the lining increases the adhesion of the balls to the surface of the lining, slows down its wear, and increases the service life of the lining.

In addition to the elastic forces of the elastomeric element, the retaining force for the balls in the niches is provided by the stiffeners. Since the stiffeners are located below the working surface of the plate, they last longer during the operation of the liner and wear out as the balls are worn, the worn balls are replaced by new ones from the loading of the mill during the grinding process without stopping the mill. The self-healing working surface maximizes the service life of the lining.

The proposed design of the lining creates conditions for the movement of the grinding balls and the loading of the mill in a stable cascade mode, which provides a relatively lower location of the separation point of the grinding balls and a changed trajectory of the movement of the grinding balls and loading in the drum. The inclined, smooth working surface of the lifters prevents the free flight of the upper layer of balls of grinding mass when they reach the point of detachment from the lining surface. When separating from the surface of the lining at the point of maximum lift, the balls of the upper layer of the grinding mass do not fly to the heel of the rollback in a loose stream of individual balls without contact with each other, but slide along the inclined working surface of the lifter and down the inclined surface of the loading mass in a dense stream.

According to the useful model, the bevel angle of the lateral working surface of the lifter is 35-60". As a result, a stable cascade mode of movement of the grinding balls is ensured. This increases the density of the balls in the mill load, increases the contact area between the balls, which in turn increases the grinding efficiency and mixing of the material by friction between the balls and

From the productivity of the mill as a whole.

According to a useful model, may contain niches of different lengths, for example, to complete a series of niches of two or more sphere diameters, in which a full niche does not fit, but only a niche of one sphere fits.

According to a useful model, the length of niches is 1-4 of the diameter of the sphere.

According to a useful model, the depth of the width of the niches is 0.85-0.95 of the diameter of the sphere.

According to a useful model, the width of the niches is 0.85-0.95 of the diameter of the sphere. Making niches with a depth less than 0.85 of the diameter of the ball will not ensure the possibility of a long stay of the ball in the niche. The execution of niches with a depth of more than 0.95 of the diameter of the ball will not provide sufficient relief of the working surface of the plate.

According to a useful model, in order to ensure the maximum density of placing balls in the plate, one niche can contain several (preferably up to four) balls. At the same time, the width of the niche is provided by 0.75-0.9 of the diameter of the ball.

Niches are located on the plate in orderly rows. Rows with niches for one ball are located at an angle of 457 to the axis of the mill drum, rows with niches for several balls are located at an angle of 30-45". The angle of placement of rows of niches of two or more diameters can be used to regulate the transverse movement of the grinding mass relative to the longitudinal axis of the mill.

According to the useful model, the niches are equipped with stiffening ribs, which are preferably made at the level of 0.7-0.8 of the diameter of the ball from the bottom of the niche. The location of the stiffening ribs below the level of 0.7 of the ball diameter will make it difficult to press the ball or balls into the niche, execution above the level of 0.8 of the ball diameter will not provide the desired time reserve for the ball to stay in the niche, as the edge will quickly wear out. Stiffness ribs can be made solid and bearing integral, depending on the size of grinding balls. In the preferred version, for balls of small sizes, continuous ribs are made.

Niches can be made with a flat or concave bottom.

The lifters are made as straight bars and are attached to the elastomer plates with fastening pins that move inside the metal box profile made along the entire length of the lifter. At the same time, the metal profile can be completely or partially immersed in the mass of the lifter. To ensure reliable fastening, the elastomeric elements are equipped with longitudinal recesses on the edges for placing lifters. The shape of the elastomeric elements can be rectangular or trapezoidal. Ceramic, or metal or cast iron balls are used as wear-resistant ball inserts.

The design of the lining, which is claimed, is explained by the drawings in which

Fig. 1 - drum mill lining,

Fig. 2 - slabs of combined self-lining,

Fig. For, 36 - plate niches, cross section.

Fig. 4a, 46 - trajectories of the loading balls inside the drum mill.

Fig. 1 shows the lining of the drum mill 1, which contains plates 2 and lifters 3, which press the plates of the lining 2 to the drum of the mill 1. On the working surface of the plates there are niches 4 in which the balls 5 are placed. As a result, the working surface of the plates is combined and includes an elastomer base of plates 2 and protruding surfaces of ball inserts 5. The upper and side working surfaces of the lifter are made smooth, and the side working surface of the lifter 6 towards the movement of the grinding mass is located at an angle of -45" to the vertical. The lifter C has a fastening unit to the drum mill 1, consisting of a metal box profile 7 that runs along the entire lifter C with a hole in the lower part along which the fastening pin 8 with a head 9 moves. The metal profile 7 is completely immersed in the mass of the lifter 3. With the help of a nut 10, a metal washer 11 and rubber gasket 12, the lifter C is attached to the drum of the mill 1. Along the lining plates 2, there are recesses at their edges, under which the shelves 13 are formed, which go under the lifter 3. For their addition plates 2 are pressed by lifter Z to the drum of mill 1.

In Fig. 2 shows various options for the location of niches in plates 2 of the lining for one ball 14 and several balls 15. The possible options for the location of the niches are not limited to those shown in the drawings. The diameter or width of the niches are chosen taking into account the diameter of the balls and the elasticity of the material of the plate 2 so as to ensure the placement and reliable fixation of the ball in the niche.

In Fig. Fig. 36 shows niches for balls in section, with a continuous 16 and a discontinuous 17 stiffening rib on the inner side surface of the niche. The stiffening ribs are located at the level of 0.7-0.8 of the diameter of the ball from the bottom of the niche and serve for additional fixation of the ball or balls after placing them in the niches. The niches are arranged in rows at an angle of В-40" to the axis of the mill drum. This arrangement of the rows facilitates the movement of balls of grinding mass along the mill drum, intensifies its mixing and grinding.

Fig. 4a, 46 shows the movement of the balls in the drum of the mill with a different lining design. Fig. 4a shows the movement of balls in the drum of a mill with a plate-lifter lining in a mixed mode, when the elastomer plate of the lining is smooth and the lateral working surface of the elastomer lifter has an angle of inclination of less than 30" When the drum rotates, the balls lie on the lifter and rise with it to the point of separation and start fall down in a mixed mode (trajectories A-A1, B-B1, C-C1, 0-01). At the same time, the flow of falling balls is loose, the contact between the balls in the flow is insignificant, there is no grinding in the area of the balls' flight.

In Fig. 46 shows the movement of balls in the drum of the mill with the proposed lining in cascade mode (trajectory E-E1,03-C1, H-NI). When the drum of the mill rotates, the balls are pressed against the drum of the mill under the action of centrifugal force and rise to a certain height. At the same time, the layer of balls touching the surface of the lining between the lifters remains stationary, because it is held by the odontogenic force and the force of friction against the working surface of the lining, formed by the spherical protrusions of the balls in the plates and the elastomeric base covered with a layer of pulp with particles of material between them. Upon reaching the point of detachment from the surface of the lining (point E), the balls of the upper layer of loading, which were tangential to the lining and which do not have a support in the form of a combined working surface of the lifters, which prevent their fall, roll down along the E-E1 trajectory, or move along the trajectories 6-21, H-NI1. The beginning of the downward movement of the upper layer of balls, when they reach the separation point, is provided by the angle of inclination of the lateral working surface of the lifter a-45". At this moment, the balls located in the next layer from the surface of the lining have already begun to move downward. The distance from the center of the balls of the next layer to the center of the drum is less, therefore, the centrifugal force acting on the next layer of balls is smaller. As a result, the point of separation of the balls from the lining surface decreases, the flow density of the upper layers of the molar mass balls moving along the trajectories E-E1, 0-C1 increases , H-No down.The movement of the balls, the grinding mass in the central loading areas does not change, because it is determined mainly by the rotation speed of the mill drum.

In the contact area of the mill loading from the heel of the rollback to the point of separation of the balls from the drum, lifters with a smooth working surface protruding above the surface of the liner plates provide vertical movements in the layers of balls, which are slightly removed from the surface of the liner, causing them to slide on the protruding surface of the lifters . As a result of increasing the density of balls in the load mass and activation of vertical movements in the layers 60 of the load, the process of grinding the material by friction in a stable cascade mode is accelerated, the mixing process is accelerated, while at the same time the wear resistance of the combined lining increases and the productivity of the ball drum mill increases.

Making the liner according to the proposed design ensures easy installation of the liner in the drum of the mill, and its property of self-recovery of its working surface increases the service life of the liner, accelerates the process of grinding and mixing the composition of several materials and increases the productivity of the drum mill.

Claims (1)

UTILITY MODEL FORMULA 10 1. Drum mill lining containing flat elastomeric plates and lifters with alternating working and non-working surfaces, the working surface of the elastomeric plates is combined and includes a protruding surface of wear-resistant ball inserts, and the lifters are made in the form of straight bars, the working surface of which includes the upper and side surfaces, while the lateral working surface of the lifter towards the grinding mass is made with a bevel, which differs in that the elastomeric plates are made with niches into which the balls are pressed and held in them due to the elastic characteristics of the material of the plates and stiffeners, which are made along the transverse contour at a level below the upper edge of the niche, and the working surface of the lifters is made smooth. 2. Lining of the drum mill according to claim 1, which differs in that the depth of the niches is 0.85-20 0.95 of the diameter of the ball. 3. Lining of the drum mill according to claim 1, which differs in that the length of the niches is 1-4 of the diameter of the ball. 4. Lining of the drum mill according to claims 1, 2, which differs in that the diameter of the niche for one ball is 0.8-0.95 of the diameter of the ball. 25 5. Lining of the drum mill according to claims 1, 2, which differs in that the width of the niche for 2-4 balls is 0.75-0.9 of the diameter of the ball. b. The lining of the drum mill according to claim 1, which is characterized by the fact that the niches are arranged in ordered rows, which are inclined at an angle of 30-45" to the axis of the drum of the mill. 7. Lining of the drum mill according to claims 1, 3, which differs in that the plate can contain niches 30 of different lengths. 8. Lining of the drum mill according to claim 1, which differs in that the stiffening rib is made at the level of 0.7-0.8 of the diameter of the ball from the bottom of the niche. 9. Lining of a drum mill according to claims 1, 8, which differs in that the stiffening rib is made continuous. 35 10. Lining of the drum mill according to claims 1, 8, which differs in that the stiffening rib is made non-continuous. 11. Lining of the drum mill according to claim 1, which differs in that the bevel angle of the lateral working surface of the lifter is at least 35-60". Mr. O Fk. 1