Mobile crushing plant

Abstract

Mobile crushing plant with a receiving hopper (1) for the material to be crushed (4) and at least two counter-rotating rollers (W) between which a working gap (A) is formed for crushing the material to be crushed (4), wherein the rollers (W) are arranged directly in the receiving hopper (1) and wherein a device for screening particles from the material to be crushed (4) that fall below a predetermined particle size is provided within the receiving hopper (1), wherein the device for screening particles is formed by at least two adjacent rollers (W) having the same direction of rotation and designed as crushing rollers with teeth, which define a screening gap (S) and wherein a discharge belt (5) is arranged on the underside of the receiving hopper (1), which runs along a feed direction of the material to be crushed (4) and which runs perpendicular to the axis of rotation of the rollers (W) over the entire length of the receiving hopper (1).

Description

[0001] The invention relates to a mobile crushing plant with a receiving hopper for the material to be crushed and at least two counter-rotating rollers, between which a working gap is formed for the crushing of the material to be crushed.

[0002] Mobile crushing plants are frequently used in the extraction of mineral materials such as ores and rock, organic materials such as coal, and for the continuous removal of overburden. To transport the extracted material or overburden from an extraction area using conveyor belts, the materials must not exceed a certain grain size. It is common practice to intermittently feed the extracted materials, or the overburden deposited above them during the exposure of the extracted material (e.g., after blasting), into the receiving hopper of the mobile crushing plant using a loader or excavator.Since the loading with the crushed material by an excavator or wheel loader is discontinuous, but the removal via conveyor belts should be continuous, the mobile crushing plant must also have a certain buffer function so that a constant conveyor belt filling and a high throughput can be achieved during continuous operation of the crushing arrangement.

[0003] For mobile applications, depending on the hardness of the material being crushed and the desired throughput, double roller crushers, jaw crushers with pre-screening, or cone crushers are used. These crushers require a relatively large height to ensure unobstructed feed, a reliable crushing process, and a uniform discharge of crushed material.

[0004] Against this background, in the well-known mobile crushing plants, the material to be crushed is fed discontinuously into the comparatively low receiving hopper by means of a belt conveyor to the crusher.

[0005] The mobile crusher must also have equipment for removing the crushed material, such as a discharge boom. The receiving hopper, conveyor belt, crusher, and discharge device with its corresponding support structure are all mounted on a common chassis.

[0006] The various elements result in a considerable overall construction volume and high weight of the mobile crushing plant, which means that with increasing nominal throughput of the plant, the investment costs rise very quickly and the maneuverability of the plant decreases.

[0007] In practice, it is desirable to use an arrangement of two parallel crawler tracks as the undercarriage, because this allows for good maneuverability through appropriate control of the two tracks. Furthermore, such double crawler undercarriages are widespread in practice, meaning that this solution involves comparatively low construction costs, and in some cases, standard designs can even be used.

[0008] Various designs of multi-roll crushers are known for stationary crushing plants. For example, US 5,595,350 A describes a multi-roll crusher at the end of a cooling unit, in which four crushing rolls are arranged side by side. From the feed side, the first rolls rotate clockwise in the same direction, while the fourth roll rotates counterclockwise. The material is continuously fed from the feed side and fed onto the crushing rolls. No crushing occurs at the simultaneously rotating rolls. Instead, small particles, i.e., a fine fraction, can fall through the gaps between the rolls, and the remaining material with a larger particle size is then crushed in the gap between the third and fourth rolls. Intermediate storage or buffering of the material is unnecessary due to the continuous feed.In the stationary setup, a large free fall height is available, and the weight and space requirements of the roller crusher are also negligible due to the stationary arrangement.

[0009] From EP 1 984 115 B1, another stationary multi-roll crusher is known in which all successive rolls alternately rotate in opposite directions. The successive rolls can be positioned so that their axes are arranged in a zigzag or stepped contour. This makes it possible to control the feed of the material to be crushed onto the individual pairs of working rolls. This can be used to ensure that all rolls are utilized as evenly as possible and that a high throughput is maintained across the entire width of the roll crusher. Pre-separation of fines is not provided.

[0010] DE 32 08 937 A1 discloses a crushing plant of this type. WO 2010 / 136 097 A1 discloses a crushing plant for comminuting raw materials, comprising a receiving hopper and a crushing unit designed as a roller crusher. US 2010 / 0 044 479 A1 discloses a method for cooling hot material, wherein the material is first passed through a cooling device and then fed to a screening device.

[0011] The present invention aims to provide a mobile crushing plant that, despite a high throughput, features a low overall height, a compact design, and low weight. In particular, the mobile crushing plant should exhibit good maneuverability to enable simple and flexible use in practice.

[0012] Starting with a mobile crushing plant with the features described above, the object of the invention is achieved by the features of claim 1. According to claim 1, the rollers are arranged directly in the receiving hopper, and a device for screening particles below a predetermined particle size is provided within the receiving hopper. Because the at least two rollers are inserted directly into the receiving hopper, a separate crushing chamber for the rollers and a separate receiving hopper are not required. In addition, long conveyor belts for transport and a complex support structure for various components are also eliminated. For a given throughput rate, this significantly reduces the weight of the mobile crushing plant.

[0013] A compact design with high throughput is further facilitated by the invention through the inclusion of a sieve for removing particles from the crushed material that fall below a predetermined particle size. Particles that are already of a size suitable for further transport or processing are thus prevented from reaching at least one working gap, resulting in a reduced material flow and a significant increase in overall throughput. Small particles that already meet the desired size requirements are removed directly by the sieve. For this purpose, vibrating screens or roller screens positioned upstream of the rollers, i.e., the crushing rollers, are suitable. According to the invention, the particle sieve is formed by two adjacent rollers rotating in the same direction, defining a sieve gap between them.These rollers are also expediently designed as crushing rollers with teeth, which creates a vibrating motion of the material being crushed and transports particles that do not fit through the screen gap between the two rollers rotating in the same direction.

[0014] To allow loading of the mobile crushing plant with an excavator or wheel loader, a feed area for the material to be crushed is conveniently located on one side of the intake hopper. The material is then conveyed from the feed area first to the particle screening unit, before the unsifted components of the crushed material are fed into at least one working gap.

[0015] As previously described, increased throughput can be achieved through screening based on size selection. A particularly preferred configuration of the mobile crushing plant includes at least five rollers arranged in the receiving hopper such that at least two working slots and one idle slot are present, with the adjacent rollers rotating in opposite directions. Additionally, a screening slot is provided between two adjacent rollers rotating in the same direction. The crushing capacity can be further increased by the at least two working slots, which, as explained in detail below, can also be designed for crushing different particle sizes.

[0016] According to a particularly suitable embodiment, starting from the feed area for separating a fine grain fraction from the crushed material, a first section is provided with at least two directly adjacent rollers having the same direction of rotation, wherein a second section following the first section for crushing a medium grain fraction has at least two rollers with the same direction of rotation and a roller with an opposite direction of rotation arranged offset downwards between these rollers, and wherein a third section following the second section for crushing a coarse grain fraction has at least a double roller crushing arrangement with two oppositely rotating rollers.

[0017] According to this design, several rollers are integrated directly into the receiving hopper in such a way that they perform a transport and screening function, size selection, and the breaking up of the medium grain fraction and the coarse grain fraction.

[0018] The feed area is typically located on one side of the receiving hopper. From this side, the material being crushed is conveyed directly, or via a relatively short conveyor within the hopper, to the particle screening unit. If at least one screen gap is provided here, the rollers are driven so that their upper surfaces move away from the feed area towards the at least one subsequent working gap. Crushing is not performed in this initial section. However, the fine particles of the material being crushed can pass through the at least one screen gap between the rollers, thus effectively screening these fine particles.

[0019] In the first section, which has at least one screen gap, the rollers can be advantageously equipped with teeth, similar to conventional crushing rollers, with the tooth tips pointing in the direction of rotation. These teeth set the material being crushed in motion, facilitating the separation of the fine particles. Additionally, larger particles that cannot pass through the roller gap are transported from roller to roller by the teeth.

[0020] The number of rollers in the first section can be selected based on the specific requirements and the particle size distribution in the material being crushed. For example, between 2 and 10, and especially between 3 and 7, rollers can be arranged in series.

[0021] The rollers of the first section are preferably arranged with their axes on a straight line and / or rising in the direction of the subsequent section. This incline allows the first roller to be positioned very low, directly above the bottom of the receiving hopper, starting from the feed area. This means that the entire height of the receiving hopper can be used for receiving and as a buffer for the material typically fed in discontinuously. The incline also creates sufficient space to arrange subsequent rollers at different heights. Finally, separation is improved because the material is conveyed against gravity.While medium and coarse grains are conveyed upwards against gravity along the successive rollers through at least one screen gap by the rollers and the back pressure of the subsequent crushed material, the fine grain fraction falls back when conveyed against gravity and finally through the screen gap between the rollers.

[0022] The first section is preferably followed by the second section, which is designed on the one hand to crush the medium-sized particles and on the other hand to transport the coarse-sized particles. In principle, the rollers arranged at the transitions between the sections can be functionally assigned to both of the adjacent sections. For example, the last roller of the first section can simultaneously function as the first roller of the second section.

[0023] The second section contains at least two rollers rotating in the same direction and at least one roller rotating in the opposite direction, offset downwards between these rollers. The at least two uppermost rollers are driven such that their upper surfaces move towards the subsequent third section. Size selection is achieved by the spacing between the at least two rollers rotating in the same direction.

[0024] Coarse particles, which due to their size do not reach the gap between the two rollers, are conveyed to the third section by the unidirectional rotation. Medium-sized particles, on the other hand, can fall into the gap between the two rollers of the second section, which rotate in the same direction, and are then crushed by the interaction with the counter-rotating roller below.

[0025] The described arrangement can be present multiple times in the second section. For size selection, the distance between two identically rotating, top-mounted rollers is always decisive. With more than two identically rotating top-mounted rollers, the distance between any two adjacent rollers can be the same or different. In particular, the gap can increase further in the transport direction, thus enabling further size selection in the second section. The distance between successive rollers with the same direction of rotation can be used to achieve optimal load distribution, i.e., maximum utilization of each individual roller.

[0026] In the third section, the coarse particles are crushed by counter-rotating rollers. Further transport is not provided at this stage. Instead, all particles that have entered the third section are drawn into the gap between the counter-rotating rollers and crushed. A particularly preferred design incorporates several, for example, four wedge-shaped crushing rollers that are driven in groups, so that even very large pieces are drawn deeper and deeper into the downward-tapering gap and successively crushed. In such a design, a first pair of counter-rotating rollers and a second, counter-rotating pair of rollers with a smaller roller gap are provided below, with the direction of rotation of both pairs directed towards each other in such a way that the material being crushed is moved into the roller gap.

[0027] The rollers in the second section, the third section, and preferably also in the first section, have the usual shape of crushing rollers with a plurality of teeth. In particular, it can be provided that in the second and third sections, in the areas where crushing takes place, the teeth of oppositely driven rollers interlock. The gap width is to be selected depending on the desired grain size of the crushed material.

[0028] In order to be able to remove the crushed material, according to a preferred embodiment of the invention a discharge belt is arranged on the underside of the receiving hopper, which runs along the feed direction of the crushed material.

[0029] The invention offers the advantage that virtually the entire length of the receiving hopper can be used for discharging the screened or crushed material, resulting in a very high overall throughput. As previously described, the design of the sections, i.e., the number, shape, and precise arrangement of the individual rollers, can be varied according to the specific requirements, particularly taking into account the particle size distribution of the material to be crushed. The screening function allows for optimal utilization in each section. For example, in the preferred embodiment with three sections, although very large particles must be crushed in the third section, the additional strain caused by crushing medium-sized particles is avoided by the prior separation process.The described arrangement of the rollers in several sections removes the medium and coarse fractions from the material being crushed, which require a significantly longer residence time in the crusher's process chamber. These fractions are then transported further and crushed in a specially designed section in the middle and at the end of the crusher, respectively. By shifting the medium and coarse fractions out of the main material flow through this transport function, the throughput fluctuations of the mobile crusher are significantly reduced, thus enabling the use of a multi-roll crusher even in mobile crushing plants.

[0030] To prevent excessive stress on the rollers located below the feed area during discontinuous feeding of the crushed material, and / or to reduce the hopper loading height (wheel loader instead of excavator), a relatively short conveying system, such as a plate conveyor, can be installed within the receiving hopper. The plate conveyor can absorb the impact energy without being damaged or subjected to excessive stress. The material conveyed by the plate conveyor is transferred directly to the synchronously rotating rollers of the first section without a significant height difference, thus avoiding mechanical stress.

[0031] As previously described, the mobile crushing plant is characterized by its compact design and low weight. Even when high throughput rates of at least 800 tons per hour (t / h) or preferably more than 1000 t / h are required, the chassis of the mobile crushing plant can consist of just two drive units, in particular two parallel crawler tracks. Depending on the material being crushed and the configuration of the mobile crushing plant, throughput rates in the range of 3000 t / h, 5000 t / h, 10000 t / h, or even 20000 t / h are possible. The use of only two drive units results in exceptionally easy maneuverability of the entire plant.

[0032] The invention provides a compact mobile crushing plant with a low overall height and low weight, thus reducing investment costs, especially for high throughput volumes, and simplifying the practical application of the mobile crushing plant. Additionally, it prevents the material to be crushed from falling onto the crushing rollers from a significant height. This reduces the risk of increased wear and malfunctions.

[0033] The invention is explained below with reference to a drawing that merely illustrates an exemplary embodiment.

[0034] They show: Fig. 1. A schematic view of a mobile crushing plant, Fig. 2 an alternative design of the in Fig. 1 shown crushing plant, Fig. 3 the in Fig. 1. The system shown during operation. Fig. 4 an alternative roller arrangement.

[0035] Fig. Figure 1 shows a mobile crushing plant with a receiving hopper 1, a multitude of rollers W, and a feed area 3 for the material to be crushed 4. A discharge conveyor 5 is arranged on the underside of the receiving hopper 1, running perpendicular to the axis of rotation of the rollers W over the entire length of the receiving hopper 1. A chassis 6 in the form of two parallel caterpillar tracks is also indicated.

[0036] The height of receiving bunker 1 in loading area 3 is chosen to allow direct loading with a wheel loader or excavator. This loading is usually done intermittently, with receiving bunker 1 thus serving as a buffer.

[0037] According to the exemplary embodiment, the rollers W are arranged in three sections I, II, III to provide, starting from the feed area 3, a separation of a fine grain fraction 4a and a transport function for coarse grain 4c and medium grain 4b, a combined transport function for the coarse grain 4c and a crushing function for the medium grain 4b, and a crushing function for the coarse grain 4c. The first section I is formed by the rollers W, which rise slightly along a straight line.

[0038] The function of the crushing plant results in particular from the Fig. 3. In the first section I, the rollers W are driven with the same direction of rotation, in this embodiment clockwise. Accordingly, the rollers W also have teeth 7 whose tips point in the direction of rotation. Due to the clockwise rotation of the rollers W, the teeth 7 generate a vibrating motion that causes fine particles 4a to fall through the screen gap S between adjacent rollers W. Medium particles 4b and coarse particles 4c, on the other hand, are transported by the teeth 7 against gravity further toward the second section II.

[0039] The last roller W of the first section I is simultaneously the first roller W of the second section II. In the second section II, at least two rollers W with the same direction of rotation and at least one roller W, offset downwards between these adjacent rollers W, are provided, which has the opposite direction of rotation, i.e., in this case, counterclockwise. In the specific embodiment, the second section has three clockwise rotating rollers W at the top and two counterclockwise rotating rollers W below them.

[0040] In the second section II, a combined transport and crushing function is implemented. The medium-sized particle 4b of the material to be crushed 4 can pass through the gap between the upper rollers W and then be crushed at the corresponding working gaps by the interaction of these rollers W with the counter-rotating rollers W below. A gap L is created between two working gaps A due to the direction of rotation of the rollers W involved. Coarse-sized particle 4c, which does not fit through the gap between two upper rollers W of the second section II, is finally transported into the third section III for crushing by the clockwise rotation of the upper rollers W.

[0041] In the third section III, the coarse grain 4c is crushed by counter-rotating rollers W. As before at the transition from the first section I to the second section II, the last roller W of the second section II is simultaneously the first roller W of the third section III.

[0042] In the described embodiment, section III contains an upper pair of counter-rotating rollers W that pre-shred the coarse material 4c. The pre-shredded coarse material 4c is then further reduced to the desired size by a second, counter-rotating pair of rollers W located below, which have a smaller roller gap, within the corresponding working gap A. The screened or crushed material 4 is then conveyed away by the discharge conveyor 5.

[0043] The system is characterized by a very compact and simple design, resulting in excellent maneuverability and low investment costs even with a comparatively high throughput. The system also boasts particularly advantageous cost efficiency during operation.

[0044] Fig. Figure 2 shows a variant of the described mobile crushing plant in which an additional, comparatively short conveying device is arranged within the receiving hopper 1 in the feed area 3. The conveying device, in the form of a plate conveyor 8, serves to absorb impact energy when the material to be crushed 4 is poured in. This prevents the rollers W of the first section I from being subjected to excessive stress from the falling material 4.

[0045] The Fig. 1 to Fig. Figure 3 relates to a preferred, possible embodiment of the mobile crushing plant according to the invention. However, a different arrangement with fewer rollers W is also conceivable. Figure 3 shows, by way of example, a figure 3. Fig.Figure 4 shows an embodiment with only five rollers W, where only the arrangement of the rollers W themselves is depicted. The further design of the mobile crushing plant with the receiving hopper 1, the discharge conveyor 5, and the chassis 6 corresponds to the embodiment described above. The material to be crushed 4 is fed in on the left side as before, with the first two rollers W forming a screen gap S from the feed area 3, at which fine particles 4a are screened out. Subsequently, the unsifted material 4 passes to two working gaps A, between which an empty gap L is formed. No further selection between medium particles 4b and coarse particles 4c takes place. However, by distributing the material 4 across the two working gaps A, a satisfactory throughput is achieved overall.

[0046] If, according to a preferred embodiment, at least one screen gap S is provided as a device for sieving particles, the mobile crushing plant has at least three rollers W to form the screen gap S at a first transition between two adjacent rollers W by means of the same direction of rotation and the working gap A at a second transition between two adjacent rollers W by means of an opposite direction of rotation, drawing in the material to be crushed 4.

Claims

[1] Mobile crushing plant with a receiving hopper (1) for the material to be crushed (4) and at least two counter-rotating rollers (W) between which a working gap (A) is formed for crushing the material to be crushed (4), wherein the rollers (W) are arranged directly in the receiving hopper (1) and wherein a device for screening particles from the material to be crushed (4) that fall below a predetermined particle size is provided within the receiving hopper (1), wherein the device for screening particles is formed by at least two adjacent rollers (W) having the same direction of rotation and designed as crushing rollers with teeth, which define a screening gap (S) and wherein a discharge belt (5) is arranged on the underside of the receiving hopper (1), which runs along a feed direction of the material to be crushed (4) and which runs perpendicular to the axis of rotation of the rollers (W) over the entire length of the receiving hopper (1). [2] Mobile crushing plant according to claim 1, characterized by , that a feed area (3) for the material to be crushed (4) is located on one side of the receiving hopper (1), wherein the material to be crushed (4) first passes from the feed area (3) to the device for screening particles before the unsifted components of the material to be crushed (4) are fed to the at least one working gap (A). [3] Mobile crushing plant according to one of claims 1 or 2, characterized by at least five rollers (W) arranged in a receiving hopper (1) such that at least two working gaps (A) and one empty gap (L) are present, in which the adjacent rollers (W) rotate in opposite directions, and that in addition a screen gap (S) is present between two adjacent rollers (W) which have the same direction of rotation. [4] Mobile crushing plant according to claims 2 and 3, characterized by , that, starting from the feed area (3), a first section (I) with at least two directly adjacent rollers (W) having the same direction of rotation is provided, that a second section (II) following the first section (I) has at least two rollers (W) with the same direction of rotation and at least one roller (W) with an opposite direction of rotation arranged offset downwards between these rollers (W), and that a third section (III) following the second section (II) for breaking up a coarse grain fraction has at least one working gap (A) between two oppositely rotating rollers (W). [5] Mobile crushing plant according to claim 4, characterized by , that the successive rollers (W) of the first section (I) are arranged in an ascending direction towards the subsequent second section (II). [6] Mobile crushing plant according to claim 4 or 5, characterized by, that the third section (III) for breaking up the coarse grain fraction has a first counter-rotating pair of rollers (W) and a second counter-rotating pair of rollers (W) arranged below with a smaller roller gap. [7] Mobile crushing plant according to one of claims 1 to 6, wherein a chassis (6) formed from two drive rows is provided. [8] Mobile crushing plant according to claim 7, wherein the chassis (6) is formed by two parallel crawler tracks. [9] Mobile crushing plant according to any one of claims 1 to 8, wherein the maximum throughput of the material to be crushed (4) is at least 800 t / h, preferably at least 1000 t / h. [10] Mobile crushing plant according to one of claims 1 to 9, wherein a conveying device is arranged within the receiving hopper (1) which feeds the crushed material (4) to the device for sieving particles. [11] Mobile crushing plant according to claim 10, wherein the conveying device is a plate belt (8).

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