Bulk material container for pulp, in particular pulp in the form of chips, use of a bulk material container and device for producing a dry-laid fibrous web

Abstract

The invention relates to a bulk material container (1) for pulp, in particular pulp in the form of chips (20), with a discharge opening (3) through which the pulp can be removed from the bulk material container (1), a discharge system (2) for further transport of the pulp and with a transition channel (7), wherein the pulp can be fed to the discharge system (2) through the discharge opening (3) and the transition channel (7).

Description

[0001] The invention relates to a bulk material container for pulp, in particular for pulp in the form of chips, a use of a bulk material container and a device for producing a dry-laid fibrous web.

[0002] The production of fibrous webs from pulp, in particular paper, board, or tissue webs, using the dry air-laying process is known and has already been described, for example, in US Pat. No. 4,167,378. The dry-laid fibrous web is produced from baled pulp in three stages: First, the baled pulp is shredded into chips in a shredder. Then, the chips are defibrated in a fiberizing device before they are finally deposited in an air-laying device to form a fibrous web. The intermediate shredding step makes it possible, in principle, to produce a fibrous web from conventional baled pulp using the dry air-laying process, as the individual chips are easier to process by the fiberizing device, such as a hammer mill, allowing the fibers to be separated more reliably.However, the quality of the fibrous web produced in this way using the dry air-laying process is still not always satisfactory.

[0003] Storing or temporarily storing the chips between individual process steps is problematic with existing solutions. Generally, the chips are collected and temporarily stored between process steps in bulk containers, also known as collection containers, silos, or storage tanks. It is particularly important that the chips can be discharged or removed from the bulk container in a continuous flow to ensure a continuous and even supply of material for subsequent process steps. However, the disadvantage of state-of-the-art bulk containers is that such continuous discharge is not satisfactorily possible.

[0004] In known solutions, the chips are removed through a discharge opening at the bottom of a bulk material container. The chips fall through the discharge opening into a downstream discharge system, also known as a conveyor system, such as a screw conveyor. However, this is not a reliable process, as bridging can occur among the chips. This means that when chips fall through the discharge opening into a transition channel to the discharge system, the chips shift against each other and against the side walls of the transition channel, forming a kind of "bridge" and preventing them from falling down, thus blocking or at least temporarily interrupting the material flow.

[0005] However, the bulk material containers known from the prior art have the disadvantage that they cannot prevent the chips from jamming behind the discharge opening. Conventional agitators used in bulk material containers cannot prevent bridging in the transition channels to discharge systems because they do not reach into the area behind the discharge opening.

[0006] It is therefore an object of the present invention to solve or at least minimize the aforementioned problems of the prior art. In particular, a bulk material container is to be provided that prevents bridging of pulp chips behind the discharge opening and enables continuous and uniform discharge of pulp chips.

[0007] This object is achieved by the independent claims. The dependent claims relate to advantageous developments of the invention.

[0008] Specifically, this object is achieved by a bulk material container for pulp, in particular pulp in the form of chips, with a discharge opening through which the pulp can be removed from the bulk material container, a discharge system for further transport of the pulp and with a transition channel arranged at the discharge opening, wherein the pulp can be fed to the discharge system through the discharge opening and the transition channel, and wherein the cross-sectional area of ​​the transition channel is larger than the base area of ​​the discharge opening.

[0009] A bulk material container designed in this way is particularly advantageous because the chips, after falling through the discharge opening, do not fill the larger cross-sectional area of ​​the transition channel and thus cannot become stuck and jammed on the side walls of the transition channel. In other words, the larger cross-sectional area of ​​the transition channel, or the resulting ratio between the cross-sectional area of ​​the transition channel and the discharge opening, creates areas in the transition channel into which the chips cannot reach. In this respect, they cannot be pressed against the side walls of the transition channel in every area of ​​a cross-section. Bridging of the chips, in other words jamming of the chips, in particular with the formation of a cavity and the associated interruption of the conveying flow, can thus be prevented or avoided downstream of the discharge opening in the transition channel.at least be reduced.

[0010] A bulk material container can also be referred to as a silo. In particular, a bulk material container can, for example, have a cylindrical basic shape or a cylindrical wall and be arranged vertically. The container base can in particular be arranged on the side or end of the cylindrical wall which faces the ground. Other basic shapes, in particular prismatic ones, are also possible for the bulk material container, for example a cube or cuboid. The container base can be flat or even. However, it is also possible for the container base to be tapered, in particular conical, and thus converge towards the ground. A bulk material container can also have one or more introduction openings through which the chips can be introduced into the container.These introduction openings can be arranged in particular in the upper area of ​​the bulk material container so that newly introduced chips are arranged on the chips already in the bulk material container.

[0011] In the context of an exemplary production process for a fibrous web from pulp, a bulk material container can be arranged between a shredder for shredding a bale of pulp into chips and, for example, a defibration device in which the chips are further defibrated. The bulk material container can serve as a kind of intermediate buffer, ensuring that a continuous flow of pulp chips can always be fed to the defibration device. Therefore, the chips in the bulk material container should be as loose and uncompressed as possible to facilitate further processing, especially to ensure that they can be fed to the defibration device in a continuous flow.

[0012] A bale of pulp can consist of a multitude of stacked pulp boards. This pulp can be, for example, NBSK pulp, which is commonly used to produce a paper, board, or tissue web using the wet process. The bale of pulp can have a density between 800 kg / m 3 and 1,000 kg / m 3 , in particular around 920 kg / m 3, wherein the individual cellulose sheets can have a thickness of between 1.0 mm and 2.0 mm, in particular of approximately 1.5 mm. The chips can essentially have the shape of an irregular polygon, with a weight-to-circumference ratio of between 5 g / m and 10 g / m or between 5.5 g / m and 8.7 g / m. In terms of its shape, a chip can resemble the shard of a broken pane of glass. It can have a plurality of essentially straight edges which together form the shape of an irregular polygon. If the length of the individual edges is added together, the circumference of the chip is obtained. If the weight of the chip is also measured, the aforementioned weight-to-circumference ratio can be easily calculated.Chips may have a first dimension L1 in a first direction, which may be between 25 mm and 50 mm, in particular between 30 mm and 45 mm, and a second dimension L2 in a second direction orthogonal to the first direction, which may be between 10 mm and 30 mm, in particular between 15 mm and 25 mm.

[0013] A discharge opening can, for example, be formed as a recess in the wall or housing of the bulk material container. A discharge opening can, for example, have a substantially round, in particular circular or elliptical, an angular, for example rectangular, basic shape, or a shape formed from straight and / or curved sections. A discharge opening can also have a height - provided it is formed in a vertical or inclined region of the bulk material container. In this respect, a discharge opening can also be designed in the form of a channel, which protrudes, for example, from the wall of the bulk material container. A discharge opening can be arranged laterally on the bulk material container. In particular, a discharge opening can be arranged on the bottom of the bulk material container, for example in the container bottom. Multiple discharge openings can also be arranged in the bulk material container.

[0014] A discharge system can be used to transport the pulp from the discharge opening to another system or station within the exemplary manufacturing process. For example, a discharge system can be used to transport the chips to a fiberizing device, where the chips are further fiberized. A discharge system can be designed, for example, as a screw conveyor system or have a pneumatic operating principle, i.e., as a thin-flow or thick-flow conveyor. Other discharge systems are also possible, such as a tubular cable conveyor.

[0015] A transition channel can be designed to transport the chips from the discharge opening to the discharge system. In this respect, a transition channel can, for example, have four side walls and a rectangular cross-section. It is also possible for a transition channel to comprise, for example, a partial region of a discharge channel, in particular a partial region of a discharge channel surrounding the conveyor system. In this respect, for example, the walls of a substantially horizontally arranged discharge channel can, at least in regions, also form the walls of a substantially vertically arranged transition channel. A transition channel can, for example, be arranged vertically and be arranged on the underside directly adjacent to the bulk material container, in particular directly adjacent to the discharge opening.

[0016] The cross-sectional area of ​​the transition channel is larger than the base area or cross-sectional area of ​​the discharge opening. The cross-sectional area of ​​the transition channel can change, in particular expand, along the course of the transition channel. Accordingly, the transition channel can, for example, be arranged with a cross-sectional area at the discharge opening that is the same size as or insignificantly larger than the base area of ​​the discharge opening at the connection point, but then expands further in the discharge direction. The cross-sectional area of ​​the transition channel is larger than the base area of ​​the discharge opening along the entire course of the transition channel. The opening of the transition channel is aligned opposite the discharge opening and in particular arranged concentrically thereto. However, it can also have a particularly horizontal offset from the discharge opening, wherein the discharge opening is arranged above the transition channel.

[0017] The discharge opening can be designed to be smaller than the cross-sectional area of ​​the transition channel. Likewise, an additional component can be incorporated into the transition channel, the bulk material container, and / or the discharge opening, which at least partially closes the discharge opening. Such a component can, for example, be designed in the form of a closure plate. Such a closure plate can, for example, be placed on or inserted into the container base or into a recess in the container base, inserted into the discharge opening, or arranged on at least one of the side walls of the transition channel and protrude into the discharge opening.

[0018] In one design of the collection container, the cross-sectional area of ​​the transition channel in the material flow of the pulp immediately after the discharge opening is step-like larger than the base area of ​​the discharge opening. Accordingly, the transition channel immediately behind the discharge opening has a larger cross-section than the discharge opening, corresponding to the "step". The transition channel can, for example, be arranged directly at the discharge opening so that the transition channel completely covers the discharge opening. Furthermore, the cross-sectional area of ​​the transition channel can be aligned with the discharge opening, for example concentric with the discharge opening, or with an offset. In particular, one or more sides of a discharge opening, for example rectangular, can be arranged such that they extend over the volume spanned by the transition channel.Such a design ensures, on the one hand, that areas are formed in the transition channel behind the discharge opening in which chips cannot accumulate, or on whose side walls chips cannot collect. Furthermore, chips cannot be discharged laterally past the transition channel.

[0019] The cross-sectional area of ​​the transition channel can increase as the pulp flows through the transition channel from the discharge opening to the discharge system. In particular, the cross-sectional area of ​​the transition channel can increase continuously and / or in steps as the pulp flows from the discharge opening to the discharge system. A continuous increase means that the cross-sectional area expands homogeneously and without significant kinks, for example linearly or with large radii. In this respect, the sides of the transition channel can, for example, form a truncated cone or pyramid, at least in sections. It is also possible for one or more steps to be provided along the course of the transition channel, which cause a particularly discontinuous increase in the cross-sectional area.

[0020] In one embodiment of the bulk material container, the base area of ​​the discharge opening is approximately 50% - 80% of the cross-sectional area in at least one partial region of the transition channel; in particular, the base area of ​​the discharge opening is approximately 50% of the cross-sectional area in at least one partial region of the transition channel. In other words, in such an embodiment, the cross-sectional area of ​​the transition channel is enlarged by 20% to 50% in at least one partial region compared to the cross-sectional area of ​​the discharge opening. This makes it possible to ensure that the transition channel has a cross-section along its extent that enables the conveyance of the pulp chips without restricting the volume of the chip flow, in particular transversely to the conveying direction, which could lead to bridging in the transition channel.

[0021] In one design of the bulk material container, the discharge opening is substantially rectangular with four sides and / or the cross-sectional area of ​​the transition channel is substantially rectangular with four sides in at least one partial area. A rectangular design can be either square or in the form of an elongated rectangle. For example, a round, in particular circular design of the discharge opening and / or the cross-section of the transition channel is also possible in at least one partial area. Rectangular cross-sections are easier to arrange on straight walls, but also have areas at the corners that are less easily permeable to flow, in which pulp chips or residues can collect, particularly in an undesirable manner.

[0022] In one embodiment of the bulk material container, no more than three sides of the discharge opening are flush with the transition channel, in particular no more than two sides of the discharge opening are flush with the transition channel, in particular no more than one side of the discharge opening is flush with the transition channel and in particular no side of the discharge opening is flush with the transition channel. The discharge opening is in particular essentially rectangular with four sides, but can also have more sides, in particular in the sense of a polygon. A flush end means that the respective side of the discharge opening merges into the side wall or into one side of the side wall of the transition channel without any offset or change in cross-section. If a side is therefore not flush with the transition channel, there is an offset between the corresponding side orthe side wall of the transition channel and the side of the discharge opening. The side of the discharge opening projects beyond the transition channel or the (opening) cross-section of the transition channel. This prevents the chips discharged through the discharge opening from reaching the side wall of the transition channel directly behind the discharge opening, as the previously described offset exists on this side or side wall. This is advantageous because it prevents compaction and bridging. It can also be advantageous if more than one side, for example, all sides, of the discharge opening are not flush with the transition channel.

[0023] The discharge opening can also be designed as a polygon with more than four sides, with more than three sides being flush with the transition channel or having at least one side whose basic shape does not correspond to the basic shape of the transition channel adjoining it, so that it can project beyond the transition channel due to the different shape.

[0024] In one embodiment of the bulk material container, at least one side or at least one edge region of the discharge opening extends beyond the volume delimited by the transition channel; in particular, two or more sides or edge regions of the discharge opening extend beyond the volume delimited by the transition channel, and in particular, all sides or edge regions of the discharge opening extend beyond the volume delimited by the transition channel. A side or edge region of the discharge opening extends beyond the volume delimited by the transition channel if it does not protrude beyond or end flush with a side or side wall of the transition channel. The respective side or edge region of the discharge opening therefore does not merge (flush) into a side wall of the transition channel. There is an offset between the corresponding side or side wall of the transition channel and the side of the discharge opening.Such an offset can also be created in a flush channel by one or more components, for example a closing plate or a suitable semi-finished product, which is / are (subsequently) inserted into or on the discharge opening of a bulk material container, or by means of which part of the discharge opening is covered, so that the at least one component partially projects beyond the transition channel. As a result, the chips discharged through the discharge opening cannot reach the side wall of the transition channel across the entire cross-section immediately behind the discharge opening, since the offset described above exists on this side wall. This is advantageous because it can also prevent compaction and bridging. It can also be advantageous if more than one side or more than one edge area, for example all sides orthe entire peripheral edge area of ​​the discharge opening extends over the volume limited by the transition channel.

[0025] In one embodiment, the transition channel is designed as a partial region of a discharge channel. In this respect, a transition channel can, for example, comprise a partial region of a discharge channel surrounding the discharge system. In this respect, for example, the walls of a substantially horizontally arranged discharge channel can, at least in some regions, also form the walls of a substantially vertically arranged transition channel. A transition channel can, for example, be arranged on the underside directly on the bulk material container, in particular directly on the discharge opening, whereas the corresponding discharge channel can run substantially horizontally in order to transport the chips to a downstream system. In this respect, additional components, such as side walls, can advantageously be avoided and installation space saved.

[0026] The discharge system can be designed as a screw conveyor system. For example, a screw conveyor system can be designed as a spiral conveyor, a helical conveyor, or a centerless screw conveyor, comprising a flexible screw in a flexible or rigid tube driven by an electric motor. Such a discharge system is advantageous, for example, because it is low in complexity, efficient in performance, and highly reliable.

[0027] The discharge opening can be arranged in the container bottom of the bulk material container and / or the discharge opening can be arranged in the wall of the bulk material container. In particular, a discharge opening arranged in the wall of the bulk material container has a predefined height and can also be designed in the form of a channel which protrudes, for example, from the wall of the bulk material container. By arranging the discharge opening in the container bottom, the chips can be discharged from the bulk material container simply by the effect of gravity. In this respect, chips located at the bottom of the container can "fall" through the discharge opening and chips from layers above can slide down. This can ensure a continuous discharge of chips from the bulk material container. It is also possible to arrange several discharge openings in the container bottom.The transition channel can be arranged directly at the container bottom. This eliminates any offset, particularly vertical offset, between the container bottom and the transition channel, allowing the transition channel to be arranged directly at the discharge opening.

[0028] In one embodiment, the bulk material container has an agitator, with the discharge opening being arranged radially to the agitator. Agitators are used in bulk material containers for pulp chips, for example, to counteract bridging of the chips already in the bulk material container. The agitators loosen, among other things, jammed chips and ensure continuous discharge. Such agitators have, for example, a rotor arranged on a rotational axis, which comprises agitator blades extending radially from the rotational axis. The discharge opening can be arranged in the container base in such a way that the agitator blades sweep over the discharge opening and thus support continuous discharge from the collection container.A radial arrangement of the discharge opening to the agitator enables the discharge opening to be evenly covered by an agitator blade arranged radially on the rotor, which improves the filling of the discharge system through the discharge opening.

[0029] Instead of an agitator, the bulk material hopper can also be equipped with a chain conveyor or a moving floor, for example, to prevent bridging of the chips in the bulk material hopper. When using such a system, the discharge opening must be positioned appropriately to support the continuous discharge of chips into the discharge system.

[0030] In an embodiment in which stirring blades sweep over the discharge opening or the pulp chips are introduced into the discharge opening by another device with a lateral movement, it can be advantageous if the discharge opening projects beyond the transition channel, particularly on the side from which the chips are at least partially introduced into the discharge opening. This causes the chips to reach, in particular, the opposite side of the transition channel, so that a cavity can form beneath the projecting side of the discharge opening, thereby preventing bridging of the chips within the conveying flow, at least in this region of the transition channel.

[0031] In one embodiment, the container base is flat, in particular as a flat base plate, and / or arranged horizontally or inclined with respect to the horizontal and / or the container base can have a substantially circular basic shape. The container base can be designed as a flat base plate, for example as a circular flat base plate of a cylindrical wall of the bulk material container. The container base, which is in particular flat, can be arranged inclined with respect to the horizontal. This can improve the discharge of the pulp from the bulk material container, since the pulp moves more easily into the lower region of the base plate with the aid of gravity. In particular, the at least one discharge opening is also arranged in this region of the bulk material container which is lower due to the inclination of the container base.The inclination of the tank bottom results in a slight increase in the overall height of the bulk material tank, even with the same cross-section and volume. Depending on the inclination of the tank bottom, the circular basic shape of the tank bottom can also be adapted to an elliptical shape. Likewise, the wall of a tank with an inclined tank bottom can also have an elliptical basic shape, allowing the use of a circular base plate in conjunction with an agitator with a rotor rotating around a rotational axis.

[0032] The container bottom can be tapered, and / or the container bottom can have a substantially conical basic shape. In this respect, the container bottom can be conical, for example, if the bulk material container is designed as a vertical silo, and tapers towards the ground. A conical design can be advantageous, for example, because it allows for even and even discharge of the chips by gravity.

[0033] The invention further relates to a use of a bulk material container according to at least one of the above-described examples for producing a dry-laid fibrous web, preferably a tissue, paper or cardboard web or a nonwoven web, in particular a tissue web with a basis weight of 28g / m 2 up to 42g / m 2 .

[0034] The invention further relates to a device for producing a dry-laid fibrous web, in particular a paper, cardboard or tissue web, from bale pulp, which comprises a plurality of pulp plates stacked one above the other, comprising: - a shredder designed to produce chips from the bale pulp; - a defibration device designed to defibrate the chips in a dry process; and - an air-laying unit designed to form a dry-laid fibrous web from the fibers; wherein a bulk material container according to one of the aforementioned examples is provided and designed to receive chips produced in the shredder and, in particular, to feed them directly or indirectly to the defibration device.

[0035] In other words, the bulk material hopper is located between the shredder and the defibration device with respect to the material flow of the chips. The bulk material hopper serves as a kind of intermediate buffer and for the temporary storage of the chips, ensuring that a continuous flow of chips can always be fed to the defibration device. The chips can be fed to the defibration device, for example, by means of a conveyor device, such as a screw conveyor or an air-pressure-driven conveyor.

[0036] In the bulk material container, the chips should be as loose and uncompressed as possible in order to facilitate further processing, particularly to feed them into the defibration device in a continuous stream. It has proven advantageous if the density of the pulp in the bulk material container, where the pulp is in chips, is no more than a quarter of the density of the pulp before shredding, where the pulp is in the form of baled pulp. The density of the pulp in the bulk material container can be easily determined by dividing the total weight of all chips in the bulk material container by the internal volume of the bulk material container, at least up to its fill level if it is not completely full. When using a typical baled pulp with a density between 800 kg / m 3 and 1,000 kg / m 3As a starting material, this results in a maximum density of the pulp in the bulk container between 200 kg / m 3 and 250 kg / m 3 .

[0037] Exemplary embodiments of the present invention are illustrated below using purely schematic drawings. In the drawings: Fig. 1 an embodiment of a bulk material container according to the invention in a schematic sectional view, Fig. 2 a partial area of ​​a further embodiment of a bulk material container according to the invention in a schematic sectional view, and Fig. 3 a schematic representation of an apparatus for producing a dry-laid fibrous web, comprising an exemplary bulk material container according to the invention.

[0038] In all figures, the same reference numerals are used for the same or technically identical parts and components.

[0039] Fig. 1 shows an embodiment of a bulk material container 1 according to the invention in a schematic sectional view. The bulk material container 1 is designed for pulp, in particular pulp in the form of chips 20, and comprises a discharge opening 3 through which the pulp can be removed from the bulk material container 1. In addition, the bulk material container 1 has a discharge system 2 for further transport of the pulp and a transition channel 7, wherein the pulp can be fed to the discharge system 2 through the discharge opening 3 and the transition channel 7. The cross-sectional area 7A of the transition channel 7 is larger throughout the entire transition channel 7 than the base area 3A of the discharge opening 3. In the illustrated embodiment, the opening of the transition channel 7 is arranged, in particular, concentrically with the discharge opening 3.

[0040] The bulk material container 1 further comprises an agitator 4 comprising a rotational axis 5 and a rotor 6 arranged on the rotational axis 5. The rotational axis 5 is vertical in the direction of the longitudinal extent of the bulk material container 1 and is arranged centrally and in the interior of the bulk material container 1. The bulk material container 1 is essentially cylindrical in shape and its container bottom 8 is flat with a circular base area. The bulk material container 1 is arranged perpendicular to the ground and in Fig. 1 in a side view, with the wall 9 of the bulk material container 1 shown in section. A discharge opening 3 is arranged in the container base 2, which in the exemplary embodiment has a rectangular base area 3A. The base area 3A is designed as a recess in the container base 2. The chips 20 can be discharged or removed from the bulk material container 1 through the discharge opening 3, in particular with the aid of the rotor 6. Since the bulk material container 1 is arranged perpendicular to the ground, this occurs in particular through the force of gravity.

[0041] The discharge system 2 is designed as a screw conveyor system with a conveyor screw 10. The conveyor screw 10 is horizontally aligned and runs within a discharge channel 11, which is also horizontally aligned. The transition channel 7 merges into the discharge channel 11 and connects the conveyor screw 10 to the discharge opening 3.

[0042] The transition channel 7 is thus designed to transport the chips 20 from the discharge opening 3 to the discharge system 2. In the exemplary embodiment, the transition channel 7 has four side walls 7B and a rectangular cross-section 7A. The transition channel 7 directly adjoins the discharge channel 11. The transition channel 7 is arranged vertically and is located on the underside directly on the bulk material container 1 or directly on the discharge opening 3. Thus, there is no vertical offset between the container bottom 8 and the transition channel 7.

[0043] The cross-sectional area 7A of the transition channel 7 is larger than the base area 3A of the discharge opening 3 in the material flow of the pulp immediately after the discharge opening 3. The transition channel 7 is arranged on the discharge opening 3 in such a way that it completely covers the discharge opening 3. In addition, the two illustrated sides 3B or edge regions 3C of the rectangular discharge opening 3 are arranged in such a way that they extend over or partially protrude beyond the volume spanned by the transition channel 7. Such a configuration can ensure that areas in the transition channel 7 are formed below the discharge openings 3 or their sides 3B or edge regions 3C in which no chips 20 accumulate.

[0044] The two illustrated sides 3B or edge regions 3C of the discharge opening 3 are not flush with the transition channel 7, so that there is an offset between the corresponding side wall 7B of the transition channel 7 and the side 3B of the discharge opening 3. As a result, the chips 20 discharged through the discharge opening 3 cannot collect directly behind the discharge opening 3 on the side wall 7B of the transition channel 7.

[0045] Fig. 2 shows a partial area of ​​a further embodiment of a bulk material container 1 according to the invention in a schematic sectional view. Fig. The bulk material container 1 shown in Figure 2 essentially corresponds to the one shown in Fig. 1, which is why reference is also made to the description therein. The Fig. 2 is compared to the side view shown in Fig. 1, rotated by 90° with respect to the axis of rotation 5. Fig. Figure 2 shows the conveyor screw 10 from the left. Arrow 4A indicates the direction of rotation of the agitator 4 above the discharge opening 3. By sweeping over the discharge opening 3, the agitator 4 assists in conveying the chips 20 into the discharge opening. Due to the direction of rotation of the agitator 4, the chips 20 reach the opposite side 7B of the transition channel 7, so that a cavity 7C forms below the projecting side 3B of the discharge opening, which prevents bridging of the chips within the conveying flow, at least in this area of ​​the transition channel.

[0046] In the Fig. 2, a closure plate 15 is introduced into the transition channel 7 and into the discharge opening 3. The closure plate 15 partially closes the discharge opening 3 and in the process reduces the base area 3A of the discharge opening 3. The closure plate 15 is L-shaped in its cross-section and is arranged with its first end 15A on a side wall 7B of the transition channel 7. It projects with its second end 15B into the discharge opening 3 and thus reduces the base area 3A of the discharge opening 3. In other words, the second end 15B forms a side 3B of the discharge opening 3 which is not flush with the transition channel 7, but rather extends over the volume spanned by the transition channel 7. Such a design can ensure that an area is formed in the transition channel 7 below the discharge opening 3 in which no chips 20 can accumulate.

[0047] Fig. 3 shows a schematic representation of a device 100 for producing a dry-laid fibrous web, comprising a bulk material container 1 according to the invention.

[0048] The starting material used is a fiber material 12, in particular in the form of bales and / or plates, made of fresh fiber pulp or also called cellulose. As shown, for example, at least one bale 12 is fed to a shredder 16, in particular several bales 12 are fed to a shredder 16 in a row horizontally or vertically. A bale 12 of virgin fiber pulp can consist of a multitude of stacked pulp boards. This pulp can be NBSK pulp, as is commonly used to produce a paper, board, or tissue web using the wet process. The bale pulp 12 can have a density between 800 kg / m 3 and 1,000 kg / m3 , in particular around 920 kg / m 3 , wherein the individual cellulose panels can have a thickness between 1.0 mm and 2.0 mm, in particular of approximately 1.5 mm.

[0049] With a vertical feed, the bales 12 first enter a chute 13, beneath which a conveyor belt 14 circulates. The chute 13 is designed such that only 1 to 50, preferably 2 to 25, more preferably 3 to 10 of the pulp boards are fed simultaneously in a substantially horizontal direction to a shredder 16. Alternatively, the bales or pulp boards can also be fed to the shredder 16 without a chute 13. Alternatively, it may also be provided to feed a bale 12 with all of its enclosed cellulose panels completely or simultaneously to the shredder 16.

[0050] The shredder 16 comprises at least one shredder rotor 18 provided with projections, which is preceded by two driven feed rollers. The shredder rotor 18 can, for example, have a diameter of approximately 300 mm to 400 mm, preferably 368 mm, and can be operated, for example, at a substantially constant speed of approximately 500 to 700, preferably 620, revolutions per minute. The torque of the shredder rotor 18 can also be measured during operation, and the measured value can be used to control the speed at which the bale pulp 12 is fed to the shredder 16. The feed speed can be reduced as soon as a predetermined torque threshold is exceeded. This can be achieved by reducing the drive power or the speed of the conveyor belt 14 and / or the two feed rollers.The shredder 16 produces a plurality of chips 20 from the bale pulp 12 fed to it.

[0051] According to the invention, the shredder 16 is designed and operated in such a way that at least 50%, preferably at least 70%, more preferably at least 80%, of the chips 20 produced therein have substantially the shape of an irregular polygon, with a weight-to-circumference ratio between 5 g / m and 10 g / m, preferably between 5.5 g / m and 8.7 g / m. In terms of its shape, a chip 20 resembles the shard of a broken pane of glass. It has a plurality of substantially rectilinear edges, which together form the shape of an irregular polygon. Adding the length of the individual edges yields the circumference of the chip 20. If the weight of the chip 20 is also measured, the aforementioned weight-to-circumference ratio can be easily calculated.In the present embodiment, at least 50%, preferably at least 70%, more preferably at least 80%, of the chips 20 may weigh between 0.5 g and 1.0 g, preferably between 0.6 g and 0.9 g.

[0052] Furthermore, in this embodiment, at least 50%, preferably at least 70%, more preferably at least 80%, of the chips 20 may have a first dimension in a first direction which is between 25 mm and 50 mm, preferably between 30 mm and 45 mm, and a second dimension in a second direction which is orthogonal to the first direction, which is between 10 mm and 30 mm, preferably between 15 mm and 25 mm.

[0053] The chips 20 produced in this way can be very easily processed further and result in a high-quality fibrous web. The chips 20 produced in the shredder 16 are next fed, preferably by air flow, to a cleaning device 22. This cleaning device 22 can be, for example, a so-called air sifter. In this device, the chips 20 are fed into a riser pipe through which air is blown from below by a blower 24. The chips 20 are washed around and swirled by the air flow, dislodging impurities 26, such as sand or the like. These impurities 26 fall downwards in the riser pipe due to gravity against the air flow, where they can exit the riser pipe. The chips 20, on the other hand, are carried upwards by the air flow and next reach a cyclone air separator device 28, where the air is separated from the chips 20.The separated air can, for example, as in . Fig. 1 is indicated by an arrow, the chips 20 are returned in front of the cleaning device 22.

[0054] The cleaned chips 20 fall downward from the cyclone air separator device 28 into a bulk material container 1. The density of the pulp in the bulk material container 1, where the pulp is present in chips 20, is preferably at most one-quarter of the density of the pulp before shredding 16, where the pulp is present in the form of baled pulp 12. In other words, the pulp in the form of chips 20 is preferably relatively loose in the bulk material container 1.

[0055] A continuous stream of chips 20 can be removed from the bulk material container 1 through a discharge opening 3 by means of an agitator 4. These chips can be fed by the discharge system 2, for example, a screw conveyor or an air-pressure-driven conveyor, to a fiberizing device 32, where the chips 20 are fiberized into individual fibers in a dry process. The individual fibers then enter an air-laying unit 34 to form a dry-laid fibrous web 36 from the fibers. The fibrous web 36 is formed on a rotating, air-permeable forming fabric 38, over which the fibrous web 36 is simultaneously transported. List of reference symbols: 1 bulk container 2 discharge system 3 Discharge opening 3A Base area (of the discharge opening) 3B side (of the discharge opening) 3C Edge area (of the discharge opening) 4 agitator 4A Direction of rotation (of the agitator) 5 axis of rotation 6 Rotor 7 Transition channel 7A Cross-sectional area (of the transition channel) 7B Side wall (of the transition channel) 7C cavity 8 Container bottom 9 Wall (of the bulk container) 10 screw conveyor 11 Discharge channel 12 bales of pulp 13 Shaft 14 Conveyor belt 15 locking plate 15A first end (of the closure plate) 15B second end (of the closure plate) 16 shredders 18 Shredder rotor 20 schnitzels 22 Cleaning device 24 conveyor system 26 contaminants 28 Cyclone air separator device 32 defibration device 34 Air laying unit 36 Fibre web 38 forming screen 40 beams, crossbeams (of the connecting device) 41 Connecting ring (of the connecting device) 42 radial beams (of the connecting device) 100 Device for producing a dry-laid fibrous web QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 4,167,378

[0002]

Claims

[1] Bulk material container (1) for pulp, in particular pulp in the form of chips (20), with a discharge opening (3) through which the pulp can be removed from the bulk material container (1), a discharge system (2) for further transport of the pulp and with a transition channel (7) arranged at the discharge opening (3), wherein the pulp can be fed to the discharge system (2) through the discharge opening (3) and the transition channel (7), and wherein the cross-sectional area (7A) of the transition channel (7) is larger than the base area (3A) of the discharge opening (3). [2] Bulk material container (1) according to the preceding claim, characterized by that the cross-sectional area (7A) of the transition channel (7) in the material flow of the pulp immediately after the discharge opening (3) is gradually larger than the base area (3A) of the discharge opening (3). [3] Bulk material container (1) according to at least one of the preceding claims, characterized by that the cross-sectional area (7A) of the transition channel (7) increases in the material flow of the pulp through the transition channel (7) from the discharge opening (3) to the discharge system (2), in particular that the cross-sectional area (7A) of the transition channel (7) increases continuously and / or step-wise in the material flow of the pulp through the transition channel (7) from the discharge opening (3) to the discharge system (2). [4] Bulk material container (1) according to at least one of the preceding claims, characterized by that the base area (3A) of the discharge opening (3) is approximately 50% - 80% of the cross-sectional area (7A) in at least one partial area of ​​the transition channel (7), in particular that the base area (3A) of the discharge opening (3) is approximately 50% of the cross-sectional area (7A) in at least one partial area of ​​the transition channel (7). [5] Bulk material container (1) according to at least one of the preceding claims, characterized by , that the discharge opening (3) is essentially rectangular with four sides (3B) and / or the cross-sectional area (7A) of the transition channel (7) is substantially rectangular with four sides in at least one partial area. [6] Bulk material container (1) according to at least one of the preceding claims, characterized by , that no more than three sides (3B) of the discharge opening (3) are flush with the transition channel (7), in particular no more than two sides (3B) of the discharge opening (3) are flush with the transition channel (7), in particular no more than one side (3B) of the discharge opening (3) is flush with the transition channel (7), in particular no side (3B) of the discharge opening (3) is flush with the transition channel (7) wherein the discharge opening (3) is in particular substantially rectangular with four sides (3B). [7] Bulk material container (1) according to at least one of the preceding claims, characterized by , that at least one side (3B) or one edge region (3C) of the discharge opening (3) extends over the volume delimited by the transition channel (7), in particular two or more sides (3B) or two or more edge regions (3C) of the discharge opening (3) extend over the volume delimited by the transition channel (7), in particular, all sides (3B) or edge regions (3C) of the discharge opening (3) extend over the volume delimited by the transition channel (7). [8] Bulk material container (1) according to at least one of the preceding claims, characterized by that the transition channel (7) is designed as a partial area of ​​a discharge channel (11). [9] Bulk material container (1) according to at least one of the preceding claims, characterized by that the discharge system (2) is designed as a screw conveyor system. [10] Bulk material container (1) according to at least one of the preceding claims, characterized by , that the discharge opening (3) is arranged in the container bottom (8) of the bulk material container (1), and / or that the discharge opening (3) is arranged in the wall (9) of the bulk material container. [11] Bulk material container (1) according to at least one of the preceding claims, characterized by that the bulk material container (1) has an agitator (4) and the discharge opening (3) is arranged in particular radially to the agitator. [12] Bulk material container (1) according to at least one of the preceding claims, characterized by , that the container bottom (8) is flat, in particular designed as a flat base plate, and / or the container bottom (8) is arranged horizontally or inclined relative to the horizontal and / or the container base (8) has a substantially circular basic shape. [13] Bulk material container (1) according to at least one of the preceding claims, characterized by that the container base (8) is tapered and / or the container base (8) has a substantially conical basic shape. [14] Use of a bulk material container (1) according to at least one of the preceding claims for producing a dry-laid fibrous web (36), preferably a tissue, paper or cardboard web or a nonwoven web, in particular a tissue web with a basis weight of 28g / m 2 up to 42g / m 2 . [15] Device (100) for producing a dry-laid fibrous web (36), in particular a paper, cardboard or tissue web, from bale pulp (12), which comprises a plurality of pulp plates stacked one above the other, comprising: - a shredder (16) designed to produce chips (20) from the bale pulp (12); - a defibration device (32) designed to defibrate the chips (20) in a dry process; and - an air-laying unit (34) designed to form a dry-laid fibrous web (36) from the fibers; characterized by that a bulk material container (1) according to one of claims 1 to 13 is provided, wherein the bulk material container (1) is designed to receive chips (20) produced in the shredder (16) and, in particular, to feed them directly or indirectly to the defibration device (32).

Images