DE2638687A1 - METHOD AND DEVICE FOR DISTRIBUTION OF LOOSE FIBERS ON A CARRIER SURFACE - Google Patents

Description

EIKENBERG & BRÜMMERSTEDT

PATENT LAWYERS IN HANOVER

Torsten Bengt Persson 259/67

Method and device for distributing loose fibers on a support surface

The invention relates to a method for distributing loose fibers on a carrier surface made of moving, porous carrier tape, in which the fiber material is placed in a container with a wall area formed as a sieve over one side of the carrier tape is filled and kept in vigorous agitation, passing through the fibrous material, through the sieve and through the Carrier tape through an air flow is generated by sucking the air on the other side of the carrier tape, whereby the Fibers gradually pass through the screen and collect in a layer on the moving carrier belt. aside from that the invention provides a particularly useful device for performing the method.

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A method and an apparatus of this type are described in GB-PS 1,207,556, for example. It will the fiber material is filled into a circular cylindrical tub which is provided with a flat, perforated bottom, the represents the sieve, with the bottom arranged at a parallel distance just above the moving carrier belt below is. A stirrer consisting of two is used to apply the vigorous movement of the fiber material in the vicinity of the sieve bottom vertically arranged rotor shafts attached to a planetary gear set located above the tub exist the lower ends of which, immediately above the sieve bottom, have radial, vertically oriented impeller-like fins or blades are attached that swirl around in the lower fiber material layer. Below the vat and below the carrier tape a suction chamber is arranged, which creates an air flow through the fiber material in the vat and through the sieve bottom and the carrier belt pulls, whereby the loosened fibers are pulled out near the bottom and in a fairly even layer be deposited on the moving belt. The belt transports the layer on to a binding and post-treatment station, in which the layer is processed into a fiber fleece for a variety of purposes.

The vigorous stirring of the fiber material is intended to ensure that the fibers are mixed with air stay and be rearranged again and again with respect to the neighboring fibers, giving them the opportunity sooner or later get through the fine holes in the sieve together with the suction air. The degree of realignment of the fibers is highest where the blade edge speed is greatest, i.e. provides an effective hold in motion

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attached to a circular ring, near the outer one Sheet edge areas. However, it can be observed be that because of the centrifugal forces that try to blow the fiber material away from this surface at Increasing the impeller speed increases the excretion capacity of the device only to a certain extent Point increased, after which it drops again, i.e. the maximum capacity that can actually be achieved is not as high as it actually is desired.

According to a further known method, the fiber material is placed in a rotating drum located between a drum and a cylindrical space located in a screen housing, the drum having a number of radially protruding needles which are used to loosen up and rearrange the fiber material. However, the fiber material tends to settle in the space move very quickly together with the drum surface, reducing the speed of the needles relative to the fiber material nowhere near as great as the absolute needle speed. This is the ability of the needles to be one To achieve realignment of the fibers and thus the excretion capacity is relatively low.

It is the object of the invention to propose a method and a device of the type mentioned at the outset, with which a high elimination capacity is achieved in a simple manner.

The invention consists in that the fiber material is kept in motion by whipping. The one here and in the following The term "whipping" as used is intended to refer to the process of repetitively moving, relatively, through the fiber material to be whipped

describe small link, the dimensions of which are chosen so that although it is along the path of movement in the structure of the surrounding fiber material creates a certain turbulence, but without the fiber material to a greater extent in the lashing direction to move, so that the material lying around the path of movement of the whip member stormily separated and displaced will.

When dry fiber material or other loose material is whipped in air in this way, the remain Fibers or particles in an airborne, flowable state, with the whipping a high degree of rearrangement of the Fibers or particles caused without pushing them with the whip. As a result, the fibers or particles easily sucked out of and through the holes in the sieve, assuring a large excretion capacity. An increased whipping speed first causes an increased rate of rearrangement of the fibers or particles and then an increased elimination capacity even within wide limits.

It may be difficult to whip up in practice to bring into effect all material that is on the surface of the container screen, but attempts have shown that very good results are obtained when the whipping is carried out in spaced areas along the Sieving is carried out, wherein the fiber material is moved relatively slowly from one whip area to the other. That Once whipped, material will remain in its airborne, flowable state for some time and it is when the whipping is repeated shortly thereafter as a result of the transport to the next whipping area along the screen, even between

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the whip areas will be able to exit through the sieve holes.

The movement of material from one whip area to the other is easily controlled by the whip limbs themselves causes when these are moved in the immediate vicinity of the sieve in the same direction of rotation, which leads to a general, relatively slow flow of material along the areas. In an absolute sense, this can very well be a quick move, however, it is slower than the speed of the whip limbs.

In an embodied apparatus for carrying out the invention, a very important feature is that rotating whips are used which rotate in a non-parallel plane to the screen, the whips cause the fiber material to be thrown against the sieve and thereby the penetration of the fibers or particles through the Sieve is supported. The axes of the usual shafts can be fixed, while the rapidly rotating, peripheral whip link areas are passed close to the sieve without, however, the remaining link areas, moving at a slower speed, are guided close to the screen, where they are rolled instead of Whipping the material can lead to flake formation.

The invention on the basis of exemplary embodiments which are illustrated in the drawing will be explained in more detail \; it mean:

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Fig. 1 is a side view of the device according to the invention in a first embodiment / partially in section,

Fig. 2 is a cross-sectional view of the device in Fig. 1,

3 shows a plan view of a detail from FIGS. 1 and 2,

FIG. 4 is an isometric view of the device according to FIG. 1,

5 shows an isometric view of a modified detail of the device according to FIGS. 1 and and

6 shows an isometric view of the device according to the invention in a further exemplary embodiment.

Fig. 1 shows an elongated fiber distribution container with semicircular ends 2, each a vertical, cylindrical Upper part 4, a downwardly directed, conically shaped lower part 6 and a horizontal, semicircular base 8 exhibit. The ends 2 are connected to one another by means of vertical side walls between the upper parts 4; all with the Parts designated by reference numerals 2 to 10 are made of non-perforated Plate material.

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Between the side walls 10, the lower parts 6 and the Bottom 8, a sieve 12 is arranged, which is permeable to fibers and air and has a U-shaped cross-sectional shape corresponding to the Has ends 2, that is to say is provided with a horizontal area 14 and two inclined areas 16. The container 1 becomes held with the help of columns 18 across a horizontally arranged carrier tape to form a fiber layer, which consists of a fine-meshed sieve or wire mesh 20 is drawn endlessly around rollers 22 and is driven by a drive device (not shown) is moved forward in the direction of the arrows shown in Fig. 2.

Below the screen 12 and the wire mesh 20, a suction chamber 24 is arranged with a trigger 26, which with the help is held by struts 19 attached to the columns 18. the Suction chamber 24 has a closed bottom, closed sides and an upper opening 28 which is just below the The underside of the wire mesh 20 is arranged and is sealed off from this with the aid of sealing strips 30. On the A horizontally arranged slide 32 is arranged on one side of the suction chamber 24, which is used to adjust the suction area has a curved edge portion 34 and will be described in detail further below. On the one upper part 4 is a Bracket 36 attached, on which a motor 38 is arranged, which with the help of a chain drive 40 four vertically arranged, drives shafts 42 running in bearings 44, the bearings being accommodated in cross members 46, which in turn are located on the side walls 10 are attached. The shafts 42 are in a row the vertical plane of symmetry of the container 1 and each have three pairs of diametrically, in the radial direction • attached, flat elongated whip links 48

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on, the length of which is adjusted in such a way that, during rotation, their tip portions the inclined portions 16 of the Sweep over sieves 12 at a short distance, with the lowermost whip links directly above the bottom area 14 of the sieve 12 are arranged. The latter therefore rotate in a common, horizontal plane above the bottom area 14, while all other whip links are axially offset and rotate in partially overlapping areas.

On the broad sides of the container 1 is provided with outer wall panels 50, which together with the side walls 10 a Form flushing channel 52, which is closed on its sides with the aid of bulkheads 54. The wall panels 50 and the bulkheads 54 extend right down to the wire mesh 20 and define a substantially triangular space between the inclined Areas 16 of the screen 12 and the wire mesh 20, this space is shielded except for the upper opening of the flushing channel 52. The wall panel 50 has at its lower edge a right-angled bend, forming an air lock 56 through which the wire mesh can pass, on which a layer of fibers is placed, as will be described below.

During operation, the shafts 42 are driven at such a speed that the tips of the whip limbs move at a speed of approximately 50 m / sec. Such a speed is for example used to treat Cellulose fibers suitable; it can of course be adapted to the desired product and vary within very wide limits. Through the bottom area 14 and the inclined areas 16 of the sieve 12, through the wire mesh 20, the suction chamber 24 and through the exhaust 26, an air flow is generated. Through the flushing

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channel 52 air is also sucked through.

A fluffed material, such as a cellulosic fiber pulp, is introduced by means of an inlet distributing the fibers 58 filled into the container 1 up to approximately the height at which the uppermost whip 48 is located, and with the aid the rapidly rotating whip limbs 48 in violent motion kept lashing through the material. Because of the same sense of rotation of all whip links 48, the fiber material against the opposite inclined areas 16 of the Sieve 12 thrown, the material surface assumes a shape that is shown in Fig. 2 with a dashed line a is. The fiber material lying on the inclined areas 16 is driven forward by the whip members 48 and moves thereby looks along the corresponding wall areas, that is along the sides and ends of the container 1 in a relatively slow flow. The fibers run through here from the Whip limbs swept areas where they are violently whipped and rearranged and where their airborne, Maintain the flowable state until they reach the next lash area with said flow. To this Thus, the inclined areas 16 and the outer edge zones of the bottom area 14 of the screen 12 are continually of one sustainably "liquefied" stream of fibers which can easily be sucked through the sieve 12 is swept over. After this When the fibers pass through the sieve, they follow the suction air and are placed on the wire mesh 20, which the fibers of which separates the air and thus creates a layer of loose fiber material, due to the movement of the wire mesh through the lock 56 for fixation or to another desired Purpose is transported.

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Some fibers have a tendency to catch on the inside of the edge panels 50 and bulkheads 54, like them however, this is prevented by the fact that an air flow passes through the flushing channel on the inner side of these walls. Sucking in a certain amount of air in this direction towards the wire mesh has another advantage: some areas of the fiber layer on the wire mesh may have a smaller thickness, which then automatically to the desired uniformity of the layer thickness of loose fibers as more air passes through the thinner areas than through the thicker areas, with from the top Dispersion zones in the immediate vicinity of the inclined areas 16 more fibers to the thin areas in a higher one Concentration as typically directed above the layer. Should be of the sieve areas used by the Tips of whip limbs 48 are swept at close range, so a greater rate of fibers will be excreted In this way, the resulting uneven distribution of the fibers is counteracted. It should be noted that the longest path for the fibers from the sieve to the wire mesh starts from the upper sieve areas, i.e. from areas which are located near the highest velocity field of the whip limbs, i.e. with regard to fiber separation the represent the most active areas.

Inside the container 1, the direction of flow of the fiber material is reversed at the ends 2, with the material is thrown around and in an upward direction along the conical bottoms 6 into one of the cylindrical tops adjacent area, from where it descends with the help of guide plates 60 along the longitudinal side

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wall parts is pressed etc. During the reversal of the flow direction Heavy particles or possibly formed tufts of fibers or other foreign bodies collect on the fiber material in an area above the conical lower parts 6 on the outer peripheral surface, from where they can be removed. For this purpose, a tangentially arranged outlet pipe 62 is arranged at this point, the inlet from a horizontal slot consists, in part, of a sliding control slide 64 for adjusting the slot height is covered, so that the outlet of e.g. foreign bodies is regulated. It is easily possible to use the outlet pipe 62 to connect to a recirculation circuit in a known manner.

The whipping members 48 may take a variety of shapes for performing their whipping function, for example as shown in FIG. At the lower end of the shaft 42 are two horizontal whip links 48 similar to one another Arms 48 'attached, but their outer ends with the help of two inclined whip members 49 are connected. In this case, the shafts 42 must be far apart be arranged that a rotation can take place in the same sense. Preferably the arms and whips have one more or less sharp front edge, while the rear edge can be flat or even, or even to create an aerodynamic one Turbulence can be covered with leaves; this makes it easier to keep the fibers flowing.

It is not absolutely necessary that the inclined areas 16 and the bottom area 14 of the screen 12 be the same Screen fineness, but a clever choice of the individual screen areas can produce a layer of loose fibers.

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made up of, for example, two outer layers of a Fiber types and a middle layer of another fiber type consists, with the different fiber types with the help the selected screen types are kept apart. Tests have shown that the invention can even be used for fibers which are longer than the fibers commonly processed with such devices.

In Fig. 6 a further embodiment of the invention is shown. The means for keeping in motion rotate here of the fiber material about horizontally arranged axes. (In Fig. 6 are identical to the other figures The same reference numerals have been used for parts of the container.) The container is equipped with a modified base area which consists of a cross-sectionally U-shaped sieve 15 with a flat underside consists. To this end, two horizontal shafts 5 are arranged in parallel, on each of which a set of whip links is attached, which can be set in rotation with the aid of a drive motor 38 and a chain 40, each of which Tips of the whip members 148 at right angles sweep over an area lying close to the sieve 15. Some of the whip limbs are designed as wings 151 with rounded ends in the manner of a propeller, with which a fiber flow in the longitudinal direction of the curved sides of the screen 15 in one direction on one side and in the other direction on the other Page is generated (see arrows). In this way the wings serve both to whip the fiber material and to constant movement within the container.

For both exemplary embodiments, that is to say according to FIG. 4 and FIG. 6, a special feature of the invention applies that

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namely the whip limbs are arranged to rotate in a plane which is not parallel to the plane of the inclined Sieve area 16 of the sieve 12 (Fig. 4) or of the sieve 15 (Fig. 6) runs. The ends of the limbs stroke very close to the respective Sxebbereich and thereby keep a zone of air-supported, flowable Fibers upright, which are thrown against the corresponding sieve areas due to the centrifugal forces, i.e. into a Direction in which the fibers easily exit through the sieve. For both execution examples it also applies that a stream of loosened Fiber material is guided along the inside of the corresponding sieve areas, with which a uniform exit of fibers through the respective Sxebbereich 15, 16 enters.

It is advantageous, although not necessary, to have the container 1 with a lid (not shown) made of sieve-like material To cover material, so that the excess air, when filling the fibers through the inlet 58 with the help of Transport air gets into the container and exceeds the air sucked out by the fume cupboard, but the fibers can escape be kept within the container.

The amount of fiber that is in the container 1 depends on the regulation of the feed rate, which in turn depends on the discharge rate; these should be adjusted in such a way that a constant profile of the fiber flow along [ the sieve surfaces is established. Experiments have surprisingly been. shows that a layer of evenly distributed fibers can be produced even without maintaining such a constant flow profile. It is even possible to pour the fibers into the container in batches and still have a steady flow

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To maintain a layer of fibers on the wire mesh until the container is practically empty; this is an extraordinary one Advantage of the invention.

The whip limbs can be of almost any shape, for example they can be made of wire. Can also Arrangement with which they are set in rotation can be carried out in almost any way, if only the end regions be repeatedly moved towards and away from the corresponding sieve areas.

The slide 32 for setting the suction area can be divided into sections, which is shown in Fig. 3 by dashed lines Lines is indicated. The sections can then be adjusted individually, thereby changing the shape of the suction opening 28 will. In this way the thickness of the layer of loose fibers can be influenced across the width, e.g. if the If the layer is to be provided with a zone that is thicker or thinner in the longitudinal direction, one or more sections Sections under this zone shifted so that the suction area in question is enlarged or reduced.

After continuous operation over a long period of time, parts of the sieve can become clogged with fibers or foreign bodies or constricted, creating a zone in which a thinner layer of loose fibers is created. This disadvantage can be eliminated by the individually displaceable sections of the slide 32, if necessary with the aid of automatic control devices will. It should be noted that this type of control of the thickness of the layer material is not only for correction of unevenness across the width of the layer, but also as a "control for the thickness of the layer im

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general can be used. This layer thickness regulation can also outside of the invention in a different context can be used, e.g. where a material base layer is applied to a mold surface with the aid of a suction effect.

It is advantageous if the openings in the inclined Areas of the screen run in the direction in which the centrifugal forces of the whip limbs act, thereby allowing penetration the fibers is facilitated through the sieve. This has a minor disadvantage, namely that some fibers are directed directly against the inner surface of the wall panel 50, where they can tower on top of each other and thus increase the risk, that lumps of fiber fall down on the fiber layer. However, the one flowing through the flushing channel 52 acts against this Airflow. Another remedy to this problem is to replace the wall panel 50 with a horizontal roller which covers part of the triangular space between the inclined portion 16 of the screen 12 and the wire mesh. In this way, the fibers are deposited on the roller surface and can be continuously removed, so that the flushing channel 52 and the lock 56 can be omitted.

- patent claims -

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Claims (15)

2838687 claims 1. A method for distributing loose fibers or particles on a carrier surface made of a moving, porous carrier belt, in which the fiber material is filled into a container which has a wall area in the form of a sieve over one side of the carrier belt and is kept in vigorous motion, wherein an air flow is generated through the fiber material, through the sieve and through the carrier belt by suctioning the air on the other side of the carrier belt, whereby the fibers gradually pass through the sieve and collect in a layer on the moving carrier belt, thereby characterized in that the fiber material is kept in motion by whipping. 2. The method according to claim 1, characterized in that the whipping is carried out in spaced apart areas arranged along the screen, the fiber material being guided in a slow movement from one area to the other. 3. The method according to claim 2, characterized in that the whipping takes place in the immediate vicinity of the screen by moving a whip member through the fiber material that the movement is transmitted to the fiber material. 7098 1 0 / 0SS7 4. The method according to claim 1, characterized in that the whipping is carried out with the aid of whip members which are rotated in a plane of rotation which intersects the sieve areas swept over by the periphery of the whip members. 5. Apparatus for carrying out the method according to claim 1, consisting of a container arranged over a porous carrier belt which is provided with means for vigorously keeping the fibrous material in motion in motion and which has a sieve facing the carrier belt, characterized in that the means for keeping the fiber material in motion consist of rapidly moving whip members (48) arranged so that the fibers are whipped in the immediate vicinity of the sieve (12). 6. Apparatus according to claim 5, characterized in that the whip members (48) are arranged at a distance from one another and are designed so that a movement of the fiber material along the screen (12) is effected. 7. Apparatus according to claim 6, with a plurality of rotating shafts serving to generate a violent movement, the axes of which are arranged parallel to one another and protrude into the container, characterized in that the axes of the shafts (42) are fixed and in a row along of the sieve (12) are arranged and that the shafts are provided with thin whip members (48), the outer sections of which are guided past the opposite areas of the sieve and rotate in a plane which have an angle different from 180 ° to the corresponding sieve area , with all whip links showing the same direction of rotation. 709810/0857 8. Apparatus according to claim 7, characterized in that the whip members (48) with respect to the shafts (42) arranged in the radial direction, at least some members of adjacent shafts are axially offset from one another and describe overlapping circular movements. 9. Apparatus according to claim 7 or 8, characterized in that the container (1) transversely to the direction of movement of the carrier tape (20) is elongated, the series of shafts (42) is arranged in the longitudinal direction of the container, that the container to screen areas contains both sides of the series and that the ends (2) of the container are fiber material impermeable. 10. Apparatus according to claim 7, 8 or 9, characterized in that the sieve (12) is formed by the bottom of the container (1) and extends upwards from this outward. 11. The device according to claim 10, characterized in that the sieve (12) at the bottom of the container (1) has a flat, parallel to the porous carrier tape (20) extending region (14) and outer inclined regions (16), wherein the Whip members (48) are arranged so that they have a frustoconical configuration adapted to the shape of the sieve areas. 12. The device according to claim 10 or 11, characterized in that a triangular cross-section space is provided between an inclined screen area (16), the porous carrier belt (20) and a wall plate (50), which via a flushing channel (52) with the outside air i ⁿ connection is established. 709810/0857 13. Device according to one of the preceding claims to 12, characterized in that the whip members (48) consist of radially protruding rods with a flat cross-sectional shape. 14. The device according to claim 13, characterized in that the opposing larger surfaces of the rods converge at least at the front edge in the direction of rotation. 15. The device according to claim 6, characterized in that in the longitudinal direction of the screen (12) a rotatable, with radial whip members (48 ') provided shaft (42') is provided, of which at least some are in the form of a propeller blade (151), whereby a movement of the fiber material takes place in the axial direction of the shaft, that is, along the screen. 709810/0857 IO Blank page