Dual-stream feed device for a high-pressure roller press

Abstract

The invention relates to a feeding device (100) for a high-pressure roller press (200), comprising at least one feeding hopper (110, 120) for receiving ground material (10) with a downwardly directed opening (115, 125) for emptying the ground material (10) into a roller gap (210) of the high-pressure roller press (200) and at least one first slide (117, 217) below the opening (115, 125) of each feeding hopper (110, 120), and a method using a high-pressure roller press with the feeding device. According to the invention, there are at least two feed hoppers (110, 120) which can be connected to one another via a second slide (150), a vibrating slide (130) being arranged between the two first slides (117, 127) and being movable from an upper position between the two first slides (117, 127) to a point immediately above the compaction zone (K) in front of the roller gap (210) of the high-pressure roller press (200), the vibrating slide (130) being connected to a vibrating device (135) which causes the vibrating slide (130) to vibrate. This allows the roller gap pressure to be easily controlled via the composition of the recirculated ground material, so that the rollers of the high-pressure roller press are not overloaded and do not vibrate undesirably during comminution.

Description

[0001] The invention relates to a feeding device for a high-pressure roller press, comprising at least one feeding hopper for receiving ground material with a downwardly directed opening for emptying the ground material into a roller gap of the high-pressure roller press and at least one first slide below the opening of each feeding hopper and a method using a high-pressure roller press with the feeding device.

[0002] High-pressure roller presses for comminuting brittle material to be ground, such as lime, silicate rock, or cement clinker, operate in an extreme physical stress range for the grinding rollers of the high-pressure roller presses. High-pressure roller presses are available in various performance classes, which differ in the width of the grinding roller and / or the circumference of the grinding roller. In all high-pressure roller presses, the effect is that a roller gap between two grinding rollers is not completely filled with ground material, or at least that the feed of ground material in the middle of the elongated roller gap between two grinding rollers is higher than at the two ends of the roller gap. With narrower roller widths, the risk of overloading the roller surface is greater than in high-pressure roller presses with wider grinding rollers. Another problem resulting from the way the ground material is fed into the roller gap is undesirable vibration of the high-pressure roller press.Vibration causes a rhythmic overload of the roller gap, causing too much material to be ground to pass through it. This causes the grinding rollers to move apart, allowing the material to fall through the open roller gap or pass through the gap with less resistance. This, in turn, causes the roller gap to close due to the restoring force of hydraulic presses mounted on the rollers.

[0003] German utility model DE 20 2012 012 460 U1 discloses a roller press with a feed device that has a shaft whose free cross-section is variable thanks to two slides to control the amount of feed material per unit of time. The slides are connected to vertical, movable shaft walls, which in turn are connected to vibrators to fluidize the feed material in the variable shaft. The composition of the feed material remains unchanged.

[0004] German patent application DE 38 06 398 A1 discloses a roller press comprising a feed device divided into two feed hoppers by a partition wall. A vertical slide allows the relative amount of different feed material from each hopper to be adjusted. Two material streams flow side by side into the grinding gap of the roller press.

[0005] The object of the invention is to reduce both problems, namely the unwanted vibration and also the overloading of the roller surfaces, which is accompanied by material breakout.

[0006] The object of the invention is achieved by providing at least two feed hoppers that can be connected to one another via a second slide. Further advantageous embodiments are specified in the dependent claims of claim 1. A method for comminuting ground material using a high-pressure roller press with the feed device is specified in method claims four to seven.

[0007] According to the concept of the invention, the feeding device for the high-pressure roller press is provided with two feed hoppers. These two feed hoppers can be connected to each other by a slide. The slide is continuously adjustable so that, depending on the position of the slide, the ground material in both feed hoppers is mixed. This design with two feed hoppers is advantageous when one feed hopper is filled with fresh material and the other feed hopper is fed with recirculation material in a closed-loop grinding plant. The recirculation material is the coarse material that, viewed in the direction of material flow, arises as coarse material in a deagglomeration device downstream of the high-pressure roller press, while fine material is separated out. According to the concept of the invention, it is also possible to provide more than two feed hoppers, which can be connected to each other by a slide.The various feed hoppers can be fed with fresh material on the one hand and recirculation material of different classification levels on the other.

[0008] The central slider allows the consistency of the ground material fed into the roller nip of a high-pressure roller press to be adjusted. Fresh material is usually in the form of small lumps of varying sizes. As it passes through the roller nip, an empty volume is created. In the event of brittle fracture in the roller nip, the breaking ground material has the opportunity to escape the pressure in the roller nip by flowing into the empty spaces. This makes comminution inefficient. The empty spaces in the fresh material can be filled by adding fines. However, this should only be done to a certain extent; otherwise there is a risk that too much ground material will pass through the roller nip, which could cause undesirable vibrations in the high-pressure roller press.By ensuring an adequate mix of the fresh material with the recirculated ground material, the behavior of the high-pressure roller press can be prevented with regard to unwanted vibration and the associated overloading of the roller surface, or at least the service life of the grinding rollers can be extended. The central slide between the feed hoppers ensures that finer material in the feed hopper reaches the empty spaces of the fresh material, and conversely, that fresh material reaches the finer recirculated material. Despite the mutual mixing, the ground material in the two feed hoppers has a different composition.

[0009] The feeding device is further provided with a vibrating slide arranged between the two first slides, which serve as dosing slides below the openings of the various feed hoppers. This vibrating slide can be moved from an upper position between the two first slides to a point immediately above the compaction zone in front of the nip of the high-pressure roller press. The vibrating slide is connected to a shaking device that causes the vibrating slide to vibrate. This vibrating slide has the effect of mixing the ground material in both feed hoppers to varying degrees depending on its position. In general, it is not necessarily advantageous for the ground material fed into the nip to be completely homogeneous. A certain degree of inhomogeneity is actually advantageous as far as vibration-free operation of the high-pressure roller press is concerned.The adjustability of the vibrating gate valve allows for adjustment of the mixing intensity. This also allows for a consistent fill level in both feed hoppers, since the amount of fresh material and the amount of recirculated material, both of which are fed into the different feed hoppers, do not have to match.

[0010] The two slides as dosing slides must not interrupt the flow of the material, but they should still function as dosing slides. To meet both requirements, it can be advantageous if the first two slides are arranged at an angle between 30° and 60° to the horizontal, preferably an angle of 45°+−5° to the horizontal. This achieves the ideal compromise between a dosing effect and an effect that does not disrupt the material flow.

[0011] The feed device according to the invention described here is best used in a closed-loop grinding plant with a high-pressure roller press. The process implemented with this device is characterized by feeding fresh material into a first feed hopper of the feed device, high-pressure comminution of the fresh material in the nip of the high-pressure roller press, deagglomeration of the press flakes produced during high-pressure comminution, separation of fines from the deagglomerated ground material, and recirculation of the coarse material produced during the separation into a second feed hopper of the feed device.

[0012] In order to regulate the operation of the high-pressure roller press in the circulation grinding plant, provision can be made for adjusting the second slide by means of a control device, wherein the control device measures vibrations on the high-pressure roller press via a detector and, depending on the measured vibration intensity, a) opens the second slide further when the vibration intensity increases and b) closes the second slide further when the vibration intensity decreases.

[0013] In order to control the operation of the high-pressure roller press in the circulation grinding plant with a further actuator, it can be provided that the vibration slide is adjusted by means of a control device, wherein the control device measures vibrations on the high-pressure roller press via a detector and, depending on the measured vibration intensity, a) further closes the vibration slide when the vibration intensity increases and b) further opens the vibration slide when the vibration intensity decreases.

[0014] In order to combine the control of both actuators, it can be provided that the first vibration slider is adjusted between each change step when adjusting the second slider.

[0015] The invention is explained in more detail with reference to the following figures. It shows: Fig. 1 a section through a feed device according to the invention, which is mounted on a high-pressure roller press, Fig. 2 a sketch of a circulating grinding plant with a high pressure roller press, with the feed device from Fig. 1, Fig. 3 a flow chart illustrating the method according to the invention.

[0016] In Fig. 1 shows a section through a feeding device 100 according to the invention, which is mounted on a high-pressure roller press 200, wherein only the two grinding rollers 202 and 204 of the high-pressure roller press 200 are shown. The feeding device 100 has the following elements: first, a feeding hopper 110, 120 for receiving grinding material 10. These feeding hoppers 110, 120 each have a downward-facing opening 115, 125 for emptying the grinding material 10 into a roller nip 210 of the high-pressure roller press 200, on which the feeding device 100 is mounted. In this figure, only the two grinding rollers 202 and 204 are shown, which form the roller nip 210 between them. A compaction zone K forms in the roller nip.In order to feed the ground material in the feed hoppers 110 and 120 onto the roller gap 210 in a controlled manner, it is further provided that the feed hoppers 110 and 120 each have a slide 125 and 127 as a metering slide below the opening 115, 125. According to the concept of the invention, it is now provided that at least two feed hoppers 110 and 120 are present, which can be connected to one another via a second slide 150. When the two feed hoppers 110 and 120 are connected, the ground materials present in the feed hoppers partially mix. Coarser fresh material in feed hopper 120 can absorb finer recirculation material from feed hopper 110 in the empty spaces between individual fresh material chunks. Conversely, coarser fresh material from feed hopper 120 can fall into the somewhat finer recirculation material in feed hopper 110. The inflow quantity from both feed devices can be controlled by the slide valves 125 and 127.A vibrating slide 130, which is excited by a shaking device 135, ensures better mixing of the two material streams when they meet at the end of the vibrating slide 130.

[0017] In Fig. 2 is a sketch of a circulating grinding plant 300 with a high pressure roller press 200 with the feed device 100 of Fig. 1. In the exemplary circulating grinding plant 300 shown here, conveyor belts 220, 240 and 260 as well as a bucket elevator 250 are used as transport means. However, it is possible to adapt the transport means according to the requirements of the specialist. Fresh material 10 is transported via a conveyor belt 220 into a first feed hopper 120 of the feed device 100. There it is guided through the feed hopper 120 to the roller gap 210 of the high-pressure roller press 200. The detailed representation and the detailed functions are the Fig. 1. Press slugs that fall out of the high-pressure roller press 200 are fed into a deagglomerator / sifter 230. This function, namely deagglomeration and sifting, can be implemented in a cascade sifter shown here. In the cascade sifter, fine material 11 is sifted out and transported for further use. Coarse material 12, on the other hand, is transported via a conveyor belt 240 to a bucket elevator 250. The bucket elevator 250 lifts the coarse material 12 and deposits it on another conveyor belt 260, which conveys the coarse material 12 into the second feed hopper 110 of the feed device 100.

[0018] Fig. Figure 3 finally shows a flowchart illustrating the method according to the invention. This method is characterized by the following steps: First, fresh material is fed 20 into a first feed hopper of the feed device 100. This is followed by high-pressure comminution 30 of the fresh material in the roller nip 210 of the high-pressure roller press 200. This step is followed by deagglomeration 40 of the press flakes produced during high-pressure comminution and sifting 50 of fines 11 from the deagglomerated ground material. It is possible for deagglomeration and sifting to be carried out in a concerted step by a cascade sifter. Sifting 50 is followed by recirculation 60 of the coarse material 12 produced during sifting into a second feed hopper of the feed device. The fines 11, however, leaves the process in the sifting step 50.

[0019] To control the grinding process, an adjustment 70 of the previously described second slide 150 can be provided with the aid of a control device 137, wherein the control device 137 measures vibrations on the high-pressure roller press 200 via a detector 205 and, depending on the measured vibration intensity, a) opens the second slide 150 further when the vibration intensity increases and b) closes the second slide 150 further when the vibration intensity decreases.

[0020] To control the grinding process, an adjustment 80 of the vibration slide 130 with the aid of a control device 137 can also be provided, wherein the control device 137 measures vibrations on the high-pressure roller press 200 via a detector 138 and, depending on the measured vibration intensity, a) further closes the vibration slide 130 when the vibration intensity increases and b) further opens the vibration slide (130) when the vibration intensity decreases.

[0021] In order to combine the two control methods, the following control strategy can be provided: an adjustment 80 of the first vibration slide 130 between each change step when adjusting 70 of the second slide 150. LIST OF REFERENCE SYMBOLS 10 ground material 11 Fine goods 12 coarse material 20 Give up 30 high-pressure shredders 40 Deagglomeration 50 prospects 60 Recirculation 70 Settings 80 Setting 100 feeding device 110 feed hoppers 115 Opening 117 sliders 120 feed hoppers 125 Opening 127 sliders 130 vibrating sliders 135 vibrating device 138 Detector 150 sliders 200 high-pressure roller press 202 grinding roller 204 Grinding roller 210 roller gap 220 conveyor belt 230 Deagglomerator / Classifier 240 conveyor belt 250 bucket elevator 260 conveyor belt 300 Circular grinding plant K Compaction zone

Claims

[1] Feeding device (100) for a high-pressure roller press (200), comprising - at least one feed hopper (110, 120) for receiving ground material (10) with a downwardly directed opening (125) for emptying the ground material (10) into a roller gap (210) of the high-pressure roller press (200), - at least one first slide (127) below the opening (125) of each feed hopper (110, 120) as a dosing slide, characterized by , that at least two feed hoppers (110, 120) are present, which can be connected to one another via a second slide (150). where between the two first slides (127) a vibration slide (130) is arranged, which can be moved from an upper position between the two first Slides (127) can be moved up to a point immediately above the compaction zone (K) in front of the roller gap (210) of the high-pressure roller press (200), wherein the vibration slide (130) is connected to a vibrating device (135) which causes the vibration slide (130) to vibrate. [2] Feeding device according to claim 1, characterized by that the two first slides (127) have an angle between 30° and 60° to the horizontal, preferably an angle of 45°+−5° to the horizontal. [3] Method for comminuting grinding material in a circulating grinding plant (300) using a high-pressure roller press (200) with a feed device (100) according to claims 1 to 2, comprising the following steps: - feeding (20) fresh material into a first feed hopper of the feed device, - high-pressure crushing (30) of the fresh material in the roller gap of the high-pressure roller press, - Deagglomeration (40) of the press flakes produced during high-pressure comminution, - prospects (50) of fines (11) from the deagglomerated ground material, - Recirculation (60) of the coarse material (12) produced during screening into a second feed hopper of the feed device. - Adjusting (70) the second slide (150) by means of a control device, wherein the control device measures vibrations on the high-pressure roller press (200) via a detector and, depending on the measured vibration intensity a) opens the second slide (150) further when the vibration intensity increases and b) further closes the second slide (150) when the vibration intensity decreases. [4] Method according to claim 3, characterized by - Adjusting (80) the vibration slide (130) by means of a control device, wherein the control device measures vibrations on the high-pressure roller press (200) via a detector (138) and, depending on the measured vibration intensity a) further closes the vibration valve (130) as the vibration intensity increases and b) opens the vibration valve (130) further when the vibration intensity decreases. [5] Method according to claim 4, characterized by adjusting (80) the first vibration slider (130) between each change step in adjusting (70) the second slider (150).

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