FI61223B - FOER FARANDE OCH APPARAT FOER BILDANDE AV ETT BANFORMIGT MATERIAL BESTAOENDE AV LOESA FIBER ELLER PARTIKLAR - Google Patents

Description

© FINLAND —FINLAND patent publication — patentskrift 6122 3 © Kv.lk?/lnt.CI.3 D 21 H 5/26 ® ® Patent application - Patentansökning J62b2k @ Application date - Ansokningsdag 2U.O8.76 • ® Start date - Giltighetsdag 2U.O8. 76 © Released to the public - Blivit offentlig 28.02.77 @ Date of display and publication—

Ansökan utlagd och utl.skriften publicerad 26.02.82

National Board of Patents and Registration © Patent granted - Patent meddelat 10.06.82

Patent and registration authorities

Requested privilege - Begärd priority 27 · 0ο · 75

England-England (GB) 35U29 / 75 (73) Scan-Web I / S, Bryggervej 21, 82U0 Risskov, Denmark-Danmark (DK) (72) Torsten Bengt Persson, Maarslet, Denmark-Danmark (DK) (7U) Letizinger The present invention relates to a process for the production of e.g. paper or nonwoven textiles and nonwoven fabrics. The present invention relates to a process used in the manufacture of e.g. paper or nonwoven fabrics and a process for forming a web-like material consisting of loose fibers or particles. the type of which appears from the preamble of claim 1.

British Patent Specification No. 1,207,556 describes a procedure and apparatus of this type for carrying out the method. The fibrous material is filled into a round, cylindrical basin with a flat, perforated bottom placed parallel and tightly at the underlying movable carrier belt, which is a wire. The substance is agitated near the perforated bottom by means of a mixing device comprising two vertical rotor shafts mounted in a planetary gear system above the basin and having radial, vertically oriented mixing vanes rotated around the material layers at just below the perforated bottom. base. Underneath the basin and the drawn wire, a suction box is placed which absorbs the flow of air through the substance in the basin and the perforated bottom and wire, whereby the fibers dispersed near the bottom are drawn out and lowered onto the drawn wire in a relatively even layer. The wire transfers the layer further to a binding or tempering station, where the layer is made into a nonwoven web material that can be used for many purposes.

By stirring the fibrous material, the aim is to ensure that the fibers are kept mixed with air and that they are accordingly rearranged relative to the other fibers, so that they can sooner or later pass through the small holes in the perforated base together with the intake air. The degree of fiber rearrangement is greatest where the speed of the wing edges is greatest, i. effective confusion is achieved in the annular region at the outer edges of the wings. However, due to the centrifugal forces that tend to force the substance out of this range, it happens that a higher blade speed only increases the power of the plant to a certain point, after which the power decreases, and the maximum achievable power is not as high as would be desirable.

According to another known procedure, the fibrous material is introduced into a cylindrical space between a horizontal roll and a perforated jacket, the roll having a large number of radial needles which disintegrate and rearrange the fibrous material. However, the fibrous material tends to move rapidly through said space along the surface of the roll, whereby the speed of the needles relative to the material does not become nearly as high as the absolute speed of the needles, reducing the need for the needles to reposition the fibers.

The object of the invention is to develop a procedure in which a high extraction efficiency is achieved in an easy manner.

According to the invention, this is achieved by agitating the substance in the container by whipping it just inside said perforated wall part. The word "whip" used in this and the following description and claims denotes an operation in which a relatively small body is moved rapidly through a mass of material to be whipped, the proportions of which disintegrates the shape of the mass in the body without moving it. movement per se to a substantial extent in the direction of movement so that the components of the mass become rapidly separated and moved along the trajectory of the body. When a dry, fibrous or otherwise loose substance is whipped in this way in the air, the fibers or particles are kept fluid and the whipping causes a large repositioning of the fibers or particles without forcing them to move with the whip body, allowing the 5 61223 fibers or particles to be immediately sucked into through, which ensures high ejection power. The higher whipping speed mainly causes the fibers or particles to be reprocessed to a greater extent, whereby the spreading power correspondingly increases within wide limits.

In practice, it is difficult to spray the substance near all surfaces of the torn wall portions of the tank, but experiments have shown that very good results can be obtained by spraying in separated areas along the torn wall and forcing the substance to move relatively slowly from one whip area to the next. If the substance is first whipped, it will remain in its fluid form for some time, and if the whipping is repeated shortly thereafter by moving the substance to the next whip area along the torn wall, the particles or fibers in the whip flow can be immediately scattered through the perforations.

Said movement of the substance from one whip area to the next can be easily effected by means of the whip pieces themselves when they are moved in a uniform manner along the perforated wall, which causes a general, relatively slow movement of the substance along the wall. This movement may very well be as fast as the absolute speed, but it is much slower than the movement of the whips.

The invention further relates to a device for carrying out a procedure as defined in the claims and as described in more detail below.

Already in this context, it should be mentioned that a very important feature of the invention is the use of rotating whips, which rotate in a non-parallel plane with respect to the torn wall part, whereby the whips cause the substance to be thrown against the perforated wall, which contributes to it. that the fibers or particles penetrate the routed wall. The whip pieces can be arranged to whip within fixed areas, and their fast-moving circumferential portions can pass very close to the torn wall area without having to move other parts that are moved more slowly just near the wall area, which could cause fiber accumulation due to relatively slow massaging or rolling; than in the episode.

The invention will now be described in more detail by way of example with reference to the drawing in which 4 61223 Fig. 1 shows a side view, partly in section, of a preferred device according to the invention, Fig. 2 shows a cross-sectional view of the device, Fig. 3 shows a detail of Figs. 1 and 2 from above; partly in section, Fig. 5 shows a modified detail, and Fig. 6 shows a perspective view of a modified device according to the invention * ·

Fig. 1 shows an elongate fiber distribution container, indicated by the general numeral 1, having two semicircular main portions 2, each with an upper semicircular portion 4 and a lower, frustoconical portion 6 with a semicircular base plate Θ. The main parts 2 are connected to the vertical side plates 10 between the upper cylindrical parts 4, and these parts 2-10 are made of non-perforated metal plate material. Mounted between the side plates 10 and the main portions 6 and 8 is a screen base indicated by the general numeral 12 which passes through fibers and air and has a U-shaped cross-section corresponding to the shape of the main portions 2, i.e. has a flat, horizontal bottom screen portion 14 and two outwardly and upwardly extending screen surfaces 16 . the container 1 is supported by columns 18 transversely fine-eyed, a horizontal carrier web above, which is referred to as the next loop of fabric 20, which is guided endlessly around rollers 22 and which is used for the non-operating position shown by displaying the direction of the arrow. A suction box 24 with an exhaust fan 26 is placed under the screen base 12 and the wire 20 and supported by beams 19 connected to the posts 18. The bottom and side of the suction box are closed and have an upper opening 28 close to the wire 20 below it and sealed against it by sealing flanges 30. One side of the suction box has a horizontal sliding plate 32 with a curved edge portion 54 guiding the suction area, as described in more detail below. At the second main part 4 is placed a bracket 36 »which supports a motor 38 which, by means of a chain drive 40, drives four vertical shafts 42 running on bearings 44» mounted on transverse support parts 46 which in turn rest on the upper edges of the side plates 10. The shafts 42 are arranged in a row in the vertical plane of symmetry of the container and are each provided with three pairs of rotor pieces 48, directly opposite each other and radially mounted, the length of which is adapted so that their outer circumferential portions pass through areas of short distance during rotation. away from the inclined screen surfaces 16, 5 61223 and in addition the lower rotor pieces are located slightly above the bottom screen part 14. The lower rotor pieces are positioned so as to rotate side by side in a common, horizontal plane above the bottom screen portion 14, while the other rotor pieces are offset relative to each other and have a length that rotates in areas that are partially overlapping.

Along the parallel long sides, the container is provided with outer wall plates 50 which, together with the side plates 10, form flushing air passages 52 closed at the sides by plate portions 54. The wall plate 50 and plate portions 54 extend tightly down over the wire 20 and enclose a substantially three-sided screen and between the wire 20, which space is protected against ambient air except for the upper opening of the purge air passage 52. The lower edge of the wall plates 50 is bent and thus forms an air barrier 56 through which the wire can pass with the fibrous layer laid on top of it, as will be explained below.

In use, the shafts 42 are rotated in the same direction, whereby the circumferential parts of the rotor bodies are moved by about 50 m / sec. speed. This speed is suitable, for example, for processing cellulose fibers, but it can be adapted to the desired product and is adjustable over a wide range. The air flow is provided through a screen base 12, a wire 20, a suction box and out through a suction fan 26. In the same way, air is sucked in through the purge air ducts 52. The disintegrated material, e.g., the cellulosic pulp, is fed into the tank through the fiber spreading inlet 58 approximately up to a level at the height of the upper rotor bodies and is agitated by rapidly rotating bodies 40 which then whip violently through the material. As the rotor bodies rotate in the same direction, the fibrous material is thrown against substantially opposite, inclined screen surfaces 16, the surface profile of the material having a shape substantially in line with the broken line in Figure 2. The material carried by the screen surfaces 16 is forced by the rotor bodies 48 to move along the respective surfaces in a relatively slow flow around the container, along its sides and ends. Those fibers which then pass through the areas of movement of the rotor bodies become strongly whipped and repositioned and remain in a fluid state until they arrive at the next whip area with said current. Thus, a stream of fibrous material is continuously passed over the outer edge portions of the screen plates 16 and the bottom screen portion 12, which can thus be immediately sucked through the screen base 12. Once the fibers have passed these screen surfaces, they follow with the intake air and are lowered onto a wire 20 which separates the fibers from the air and thus forms a loose web of fibrous material which is carried by means of the wire through the barrier 56 for solidification or the like.

, 61223 6

Some of the fibers come from e.g. due to static electricity being discharged inside the outer wall 50,54, but this is opposed by the flushing air flow which runs down the inner side of these walls when it is guided through the duct 52. Absorbing air in this way per wire also increases the tendency of any, thinner areas of the wire to become filled due to their lower suction resistance, causing the floating fibers to be drawn more centrally than other areas of the wire to provide a desirable, even distribution of fibers on the wire. If the fibers are scattered more from the sieve parts opposite the areas through which the rotor bodies pass over a short distance, an effect is obtained against the consequent, uneven distribution of the fibers. It should be noted that the longest distance that the fibers travel from the screen surfaces to the wire is from the upper screen surface portions, i. from the areas where the circumferential parts of the rotor bodies have the highest rotational speed, i.e. from the areas where the fibers are most efficiently extended.

The flow of material inside the tank is reversed at each main part 2 and thrown around and upwards along the semicircular sides 6 towards the area of the cylindrical main part 4 from which the substance is led downwards towards the longitudinal sides and bottom, etc. As the current turns, any heavy particles, fiber bundles or other nuisances to the area above the conical portion at the circumference where they can be removed. For this purpose, a lateral outlet pipe 62 is used, the opening of which towards the container is a slit which is partially locked by means of a slidably mounted sheet metal plate 64 for adjusting the height of the slit and thus for controlling, for example, the number of foreign objects. The outlet pipe 62 can be connected to the tank in a known manner by means of recirculation means.

The rotor bodies 48 may have various shapes to provide their whipping operation, e.g. according to Fig. 5, where the number 42 indicates the lower end of the shaft 42 shown in the previous figures, on which are mounted two horizontal stem bodies 48 'corresponding to the rotor bodies 48 but at the outer ends. connected by two oblique whip pieces 49. In this case, the shaft clearance must be large enough to achieve parallel rotation. The rotor bodies are preferably made with more or less sharpened front edges, while the rear edges may be flat or made or provided with vortex-forming bodies, in order to provide an aerodynamic turbulence which increases the fluidizing effect.

The device according to the invention does not necessarily have to be provided with three similar screen surfaces, but by carefully selecting suitable nets or 7 ¢ 1223 perforated sheets a loose fiber web can be formed consisting of e.g. two outer layers of short fibers around the inner layer of long fibers. . using the selected screen types. Experiments have shown that the device can also be used for fibers that are longer than the type of fiber that can normally be processed po. on a device of this type.

Figure 6 shows a modified embodiment in which the rotor bodies are mounted on horizontal shafts. Numbers indicating parts in the previous figures indicate equivalent means in Figure 6. The container 1 is provided with a modified bottom part with a net 15 with a U-shaped cross-section and a flat central part. Parallel to this are two horizontal shafts 5 * each provided with an array of rotor fragments 149 »designed to rotate in the same direction by means of a motor drive 38, 40, the outer circumferential portions of the rotating members 148 running in a region close to the screen base 15 at right angles to the base . As shown by the rounded circumferential portions, the few rotating bodies indicated by the number 50 * are shaped with a small pitch like a propeller to generate a flow of pulp along the curved side portions of the screen base 15 along one side and in the opposite direction along the other side. In this way, the rotating bodies both whip the substance and move it around in the tank.

An important feature of the invention common to both devices of Figures 4 and 6 is that the rotating bodies are designed to rotate in a non-parallel plane with respect to the screen surfaces 15 * 16, with the circumferential portions working very close to the screen surfaces to maintain a zone of efficient fluidization. , which fibers are guided by centrifugal forces towards the screen surfaces 15, 16 substantially in the direction in which the fibers pass immediately through the screen surfaces. Another feature common to both examples is that the disintegrant flows along the inside of the screen surfaces 15, 16 to obtain a uniform outflow of fibers through the screen surfaces 15, 16. The container 1 can be covered with a lid part which is an air permeable substance which allows too much air to flow out if the fibers are fed into the container with a quantity of transport air exceeding the amount of air sucked out through the exhaust fan 26 but keeping the fibers inside the container.

The amount of fibers in the tank is adjusted by the amount of feed relative to the amount of outgrowth so as to maintain a constant profile of fiber flow along the screen surfaces. Surprisingly, however, experiments show that it is possible to attenuate the orbit of evenly distributed fibers without maintaining said constant profile; it is possible to feed the fibers in measured amounts at intervals and to continuously achieve a uniform layer of fiber on the wire until the container is practically empty, which is a great advantage in the device according to the invention.

The whip pieces may have any suitable shape, e.g., wire pieces, and may be designed to rotate in any suitable manner so that their circumferential portions are moved in rapid order toward and away from the screen area cooperating with the whip piece.

The suction area adjusting damper 32 can be divided into parts, as shown by the broken lines in Fig. 3. In this case, the parts can be adjusted separately to adjust the shape of the suction area, and thus the possible thickness variations of the fiber layer can be adjusted transversely by the wire, i. if a longitudinal area in which the fibrous layer is thinner or thicker is to be made in the fibrous layer, the parts or part below this area must be adjusted so that the the suction area is increased or decreased. When the machine is used continuously for a long time, fibers or foreign objects can clog parts of the screen surfaces or wire, creating a thinner area along the length of the web. This can be prevented by separately adjustable damper parts and the control can take place by means of automation. It is clear that this method for controlling the thickness of the web formed by suction can be used not only to achieve a uniform cross-section of the fibrous layer but also as a means of adjusting the thickness of the web in general. In addition, these thickness adjusting means can be used for device types other than po. with a type of device, i.e. * in which the constituents forming the substance are placed on the fracturing surface by suction.

It should be noted that the oblique screen surfaces preferably have to form free areas when viewed in the direction of the centrifugal forces provided by the rotor bodies, which helps the fibers to penetrate through the screen surfaces. A lesser disadvantage of this is that some of the fibers are directed directly toward the inner surface of the outer wall plate 50 on which the fibers accumulate, with the risk of larger fiber piles falling on the newly formed fiber layer, but this danger can be avoided by flushing air. Another way to avoid this problem could be to replace the wall plate 50 with a horizontal roll, the longitudinal part of the surface of which covers the three-sided space between the screen surfaces 16 and the wire. The fibers deposited on this roll can be continuously removed from the outside, whereby the purge air duct 52 and the closure 56 can be dispensed with.

Claims (17)

A method of distributing loose fibers or particles on a mold surface, preferably in the dry production of paper, which mold surface consists of a movable perforated support strip (20), wherein the material to be distributed is introduced and by means of material agitating means (49, 40 49, is poured air-fluidized into an elongated distributor container formed with one or more fiber-permeable walls (16) extending over the carrier (20) and where the material is continuously discharged with the aid of an air flow submerged by the carrier. through the wall portion (16) and deposited on the support belt, the material being caused by said material-agitating means to move with a velocity component which is directed outwardly to flow through the wall portion (16), characterized in that the material in the container is made to perform a rectified general flow movement along the flow-through wall portion (16) in the longitudinal direction of the container, and the flow of material being recycled thereon. a path through an iteration, whereby in the recycled material stream, an excess of material is retained in auxiliary tile to the material flowing through the wall portion (16). 2. A method according to claim 1, characterized in that the iteration of the material stream is carried out in the opposite direction along the corresponding flow-through wall portions away over the support belt, the material stream or parts thereof also being subjected to an impact directed towards these wall parts. 3. A method according to claim 1 or 2, characterized in that new material is added to the circulating material stream p in one or more places on the flow path. 4. A method according to claim 1, 2 or 3, characterized in that the material stream between the feed and iterate web is disturbed along a pronounced curved web, at an outer part (62) which removes any lumps from the passing material. 61223 14 5. A method as claimed in any one of claims 1-4, wherein, as agitating means, whip blades (48) are used on a rotor whose shaft extends in the longitudinal direction of the container parallel to the flow-through wall part, characterized in that it extends or maintains it. rectified material flow over the entire length of the permeable wall portion (15) by means of the whip blades (5), of which Atminstones are more closely formed or arranged to produce a rectified axial fan function along the whole of said length, -terial current along the corresponding outflow wall portions (15) uses a further, corresponding whip-blade rotor, which is rotated to move the material stream in the opposite axis direction (Fig. 6). 6. A method according to any one of claims 1-4, characterized in that both the rectified flow of material along the entire length of the permeable wall part (16) and the force impact of the material directed towards said wall part are accomplished by means of a plurality of containers. longitudinally mutually separate whip-wing rotors (42, 48. rotated about parallel axes, each of which lies in a normal plane to the wall portion (16), this wall portion being inclined in relation to the rotational planes of the individual rotor blades. 7. A method according to claim 6, characterized in that the return movement of the material stream along an opposing longitudinal wall part (16) is accomplished by means of the same whip blade rotors (42, 48) arranged in the longitudinal median plane of the distributor container to act on the material flow at opposite longitudinal walls with mutually opposite direction of movement along these. Apparatus for carrying out the method according to claim 1 comprising an elongated material distributor container (2) disposed over a movable carrier belt (20) for receiving a layer of material fibers or particles from the distribution container, said container having a fiber or particle supply port. and a longitudinally flowable outflow wall portion (16) for successive delivery of material filled into the container (1) and means for agitating the material and actuating it in a direction leaking toward the inside of the outflow wall portion (16), suction of air through the perforated carrier belt for reducing and depositing the fibers or particles emitted from the dispenser on the web, characterized in that the dispensing container is additionally joined or provided with means (48, 51) for loading the container. the material in general motion in a rectified stream along the outflow wall portion (16) of its l meadow direction away over the carrier (20) and with deflection and retraction means for recirculating the stream of air-fluidized material produced in this way. Apparatus according to claim R, characterized in that the means for actuating the flowing material arranged in the container are arranged to operate in each cross-section of the material flow only a sub-area thereof with a force component directed towards the outflow wall part (16). 10. Apparatus according to claim 8, characterized in that the Ater feeders for the material stream comprise a permeable wall part (16) corresponding to said and arranged at the same level and parallel thereto, and cooperating with means for agitating the return stream and At least local influence of the current in the direction towards the return wall part (16). 11. Apparatus according to claim 8, comprising a whip-blade rotor rotatably disposed about a shaft (5) extending substantially perpendicularly to the longitudinal direction of the container parallel to the discharge wall (15), characterized in that the whip blades are at least partially positioned or designed to during rotation they cause the material to move in the axis of the rotor in one and the same direction along the entire outflow wall (16) (Fig. 6). Apparatus according to claim 8 or 9, characterized in that a series of rotors are arranged outside the discharge wall (16), each of which has a rotation axis (42) lying substantially in a normal plane in relation to the discharge wall and is formed with the whip. wings (48), whose tips in the respective rotation planes cover a small tangential area of the outflow wall (16) which is generally inclined in relation to the rotation plane of the wings. Apparatus according to claim 10 or 12, characterized in that