RU2640993C1 - Forming drum - Google Patents

Abstract

FIELD: machine engineering.

SUBSTANCE: forming drum for formation of a cloth from short fibers consists of at least two strong frames of annular shape located at a distance from each other and connected by transverse plate elements located radially and forming together with the strong frames a framework for placing a circular meshy surface. The meshy surface is formed by laying radially directed plates, one of which is inserted into the slits of the other plates, along and across the honeycomb section. According to the invention the circular meshy surface is made of at least two sections arranged in a circumferential direction and each of which is located on a separate honeycomb section made in the form of an archwise curved frame limiting the honeycomb structure composed of rectangular cells in the plan and the plates that are forming a meshy surface are located on the honeycomb section with support on the cell-forming plates. To fix the plates on the honeycomb section, a part of transversely and longitudinally disposed plates is executed with tongues with bent ends for engaging with the cell-forming plates on the back side of the honeycomb section. On the top of each frame a detachably mounted grid for the precipitated short fibers is placed.

EFFECT: improving the quality of the resulted finished product.

3 cl, 9 dwg

Description

The invention generally relates to a method and apparatus for forming a fibrous product and, in particular, to a method and apparatus for forming a fibrous product, which can be used as bulk fillers for pillows and blankets. Also, the invention can be used for the production of absorbent core disposable hygiene products, such as absorbent diapers, sanitary pads, daily pads, diapers, etc. In particular, the invention relates to the field of production of a fibrous web in an aerodynamic manner, namely to forming on a forming grid a web of aerial suspension of fibrous material, for example cellulose.

Various methods for producing molded fibrous products from fibrous materials, such as, for example, cellulose and the like, are well known to those skilled in the art. One common method for manufacturing such shaped fibrous products is to convert the starting material into pulp and then create a pulp stream involving air. The pulp with the involvement of air can be converted into a molded fibrous product using a porous molding structure under the influence of vacuum to move the pulp into the mold. This method relates to the type of dry forming the web (drylaid). This is the oldest and therefore the most common and affordable way. During pneumatic molding (airlayng) (aerodynamic molding), short fibers, mixed in a directed air flow, enter the drums, where a randomly oriented tape is formed. It turns out looser paintings than with the carding method, less durable, no oriented structure. The advantage of pneumoforming over this method is the possibility of varying the overpressure on the workpiece over a wide range.

The paper used an unconventional method of manufacturing paper - aerodynamic molding. The process of forming a fiber web is carried out by deposition on a grid of fibers from a stream of moist air while maintaining the moisture content of the formed layer at a level of 30%. This ensures the formation of fiber links without the introduction of reinforcing additives. In the structure of the fibrous layer during pressing, sections are formed on the mesh that provide mechanical strength and moisture capacity of the material. The difference between aerodynamic and traditional paper molding technologies necessitated a change in the parameters of the meshes currently used for fiber deposition. Loose sections are responsible for the high throughput of the web and are formed in the cells between the threads of the profiling grid. Dense sections determine the mechanical strength is dense. The dimensions of the dense sections and the distance between them exclude the possibility of passing the line of tearing the canvas only in loose sections.

Aerodynamic formation of the canvas is carried out using air flow, which transports the fiber into the zone of formation of the canvas. In the aerodynamic method, a web is formed on the surface of a perforated drum. Pre-loosened and mixed fibers are separated from the developing elements of the canvas by means of an air stream and transported to the place of formation of the canvas. The disadvantage of the aerodynamic method is the dependence of the quality of the web on the linear density of the processed fibers. In particular, thin light fibers clog the holes of the perforated drum, increasing aerodynamic drag and worsening their transportation conditions. One of the main technical parameters of the process is the air flow rate. At a low air flow rate, the fiber is poorly pressed against the perforated drum and the pulp is shifted, which leads to uneven web. At high speeds, the drum openings become clogged with fiber.

Thus, a molding drum is known, described in EP 0226939, where a device for forming a fibrous web is disclosed. The fibers are applied to the grid of the forming layer, which may have a recess formed in it in the form of a pocket. Under the grid is a supporting structure with a cellular structure, under which there is a device that regulates the gas flow, made in the form of a plate with holes. The specified design is made collapsible and is attached to the drum with the help of sliding elements located along the lateral surface forming the drum and blocking rings on the rim of the drum.

US 2014305570 describes a forming drum, which is a metal frame of a cylindrical shape, consisting of a set of power frames with holders, honeycomb structures with rectangular cells mounted on top of the power frames, between which a removable mesh for catching cellulose fibers is attached.

No. 4,674,966 describes a device for forming fiber pillows. The formation of pillows occurs in molds located on the peripheral part of the drum, and the molds are removable and attached to the base of the drum, made in the form of a disk, using rods (pins). Each form contains a honeycomb structure over which a mesh is attached to trap cellulose fibers.

And in US 2001043834, B25G 3/34, publ. November 22, 2001, describes the design of the connection nodes in the drum used in the production of nonwoven materials, which is a metal frame of cylindrical shape, consisting of a set of power frames, a honeycomb structure with square cells mounted on top of the power frames, onto which are fastened from above by welding mesh for catching fibers. The honeycomb structure is formed of metal plates connected by means of special slots. This decision is made as a prototype.

This patent describes a forming drum for forming a fabric of short fibers, consisting of at least two force end shapes of power frames located at a distance from each other and interconnected by transverse plate elements located radially and forming a frame for placement together with power frames secured around the circumference on the transverse plate elements of the frame of the circumferential section with a mesh surface for deposited short fibers, while on the circumferential section of the mesh melting stacking surface is formed along and across the honeycomb sections of plates, some of which are inserted into the slots the other plates, and the ends of the transversely extending plate introduced into the slot in the load-bearing frames. In this case, the outwardly oriented edges of these plates are made stepwise with the formation of hooks for gripping the fibers and eliminating their vanishing in the tangential direction.

Thus on the drum frame is formed having the ability to change, or replace, or repair the mesh surface by disassembling the plates and replacing them with new ones.

The disadvantage of this solution is its lack of manufacturability. First of all, it is difficult to mount the plates forming the mesh surface and to dismantle them, since the plates with end protrusions are inserted into the slots of the frames. Therefore, in order to replace the mesh surface with cells of one standard size with the mesh surface of another standard size, it is necessary to disassemble the drum completely so that it is possible to remove one of the frames and remove from the slots of the plate. This is also confirmed by the fact that on the outer side of one frame the elements of the fastening of the frames are made, allowing to unlock the connection between the frames.

In addition, the presence of hooks for gripping the fibers on the plates, of course, provide non-displacement of the web along the surface of the drum, but at the same time increase the adhesion to the mesh web, which leads to the difficulty of removing the web from the mesh surface. When removing the canvas, some of the fibers remain in the hooks, which requires periodic cleaning of the mesh surface, that is, it is necessary to stop the process and the device. The need to use hooks on the plates is due to the fact that the rotation speed of the molding drum is not consistent with the air pressure and fiber density. With insufficient air pressure, the fibers falling on the mesh surface of the forming drum fly off it due to the presence of centrifugal force and the appearance of tangential acceleration. In addition, increasing the pressure of the air flow also forms tangentially directed acceleration vectors, if it is not consistent with the cross-section in the grid, ensuring the removal of air flow through the canvas.

The present invention is aimed at achieving a technical result, which consists in improving manufacturability by reducing the time to replace the mesh surface and its repair.

The specified technical result is achieved in that in the forming drum for the formation of a fabric of short fibers, consisting of at least two ring-shaped power frames located at a distance from each other and interconnected by transverse plate elements located radially and forming together with the power frames a frame for accommodating a circumferential mesh surface, while the mesh surface is formed by laying along and across the honeycomb section of radially directed plates, one of which are inserted into the slots of other plates, the circumferential mesh surface is made of at least two located sections in the circumferential direction, each of which is located on a separate honeycomb section made in the form of an arcuate curved frame bounding the honeycomb structure from a rectangular shape in terms of cells, and the plate-forming surface of the plate is located on the honeycomb section based on the plate-forming cells of the plate, and for securing the plate on the honeycomb section a part of the transverse and odolno spaced plates formed with lugs with curved ends for engagement with the plates forming the cell on the back side of the cell section, and the frame placed on top of each mesh removably installed.

In this case, it is advisable that the cells of the honeycomb structure have a square shape in plan. A removable mesh installed on top of each frame is attached to the drum by pressing with the help of rods installed in the grooves in the power frames.

These features are significant and are interconnected with the formation of a stable set of essential features sufficient to obtain the desired technical result.

The present invention is illustrated by a specific example of execution, which, however, is not the only possible, but clearly demonstrates the possibility of achieving the desired technical result.

In FIG. 1 is a general view of a molding drum with callouts showing a mesh surface and mounting elements of a honeycomb section on frames;

FIG. 2 - molding drum with one honeycomb section removed;

FIG. 3 - cell section;

FIG. 4 - shows the location of the plates on the honeycomb section to form a mesh surface;

FIG. 5 shows mounting plates;

FIG. 6 - a fragment of the mesh surface on the cell section;

FIG. 7 - the first type of plate for the formation of a mesh surface

FIG. 8 - the second type of plate (with engagement elements) for the formation of a mesh surface

FIG. 9 - the third type of plate (with engagement elements) for the formation of a mesh surface.

According to the present invention, the construction of a molding drum used as a lodgement for spraying short fibers of various natural or artificial origin onto its mesh surface is considered. This molding drum is part of an aerodynamic molding facility for short-fiber web, and in which, mixed in a directed air flow, these fibers enter the surface of the molding drum, where a randomly oriented ribbon is formed. The deposition of short fibers on the mesh surface of the forming drum is due to the fact that the short fibers enter the air stream sold on or along the surface of the mesh (in the tangential direction) and pass through voids in the mesh and in the power frame of the drum into the atmosphere. The direction of the air flow causes the fall of short fibers on the mesh surface, and the coupling qualities of the fibers determine the connection (meshing) of the fibers among themselves. With layered spraying, the adhesion of short fibers provides non-disintegration of the canvas and the possibility of its use, for example, as a filler of pillows or blankets.

The technology of aerodynamic molding of a fiber web has been known for a long time and is based on a proven technology (FR 2657977, 2657077), according to which the method of forming a primary mineral wool carpet is carried out by centrifugal formation of fibers from a mineral melt in a fiber forming unit and transferring the fiber dispersion cloud from the fiber forming unit to a gas stream onto a permeable forming base moved in front of the fiber forming unit and a device for forming a primary mineral wool web carpet. Due to the fame of this process, the technology of the process itself is not considered within the framework of the present invention.

According to the present invention, a forming drum (FIGS. 1, 2) is used for aerodynamic molding installations of a short fiber web, which consists of at least two ring-shaped power frames 1 located at a distance from each other and interconnected by transverse plate elements 2, located radially and forming a frame together with power frames. In particular, the power frame can be made in the form of a disk with viewing windows and / or technological holes 3 in the wall for air to enter the cavity of the frame. All frame elements are made of metal and simplified shape, which shows the high adaptability of the frame design. So, each power frame can be made in the form of a hoop, or a flat ring, or in the form of a disk, and the transverse plate elements are made in the form of thin plates that are welded (for example, by spot welding) to the walls of the frames. Thus, the frame is a rigid, non-separable structure with the correct geometry set relative to the axis of rotation to eliminate runouts and dynamic loads on the bearings.

All transverse plate elements in the form of, for example, rectangular plates (flat or curved) are welded to the frames at a level below the peripheral edge of the frames, which allows you to form a landing bed in the circumferential direction, limited by the peripheral edges of the frames and the end edges of the plates. This bed is used to place the circumferential mesh surface 4 under the deposited short fibers. The circumferential mesh surface 4 is made of at least two located sections in the circumferential direction, each of which is located on a separate honeycomb section 5 (Fig. 3), made in the form of an arcuate curved frame bounding the honeycomb structure of a rectangular shape in terms of cells 6. Cell the structure of each frame is made of transverse and longitudinal plates, the transverse of which, for example, are welded to the frame, and the longitudinal plates are inserted into the slots in the transverse plates and fixed (callout in Fig. 3). Moreover, part 7 of the transverse plate is made higher than the height of the remaining part 8 of the transverse plate. In the plates of this part 7, in the height exceeding section above the plates of the other part 8, slots 9 are made evenly spaced along the length of the plate. The honeycomb section fits into the bed of the plate between the frames and is detachably attached to the frames. In order to form a continuous mesh surface, at least two honeycomb sections are laid and fixed detachably / detachably in the bed. And on top of each frame is a removable installed grid. The mesh may be woven or metallic. A mesh removably mounted on top of each frame is attached to the drum by pressing with the help of rods installed in the grooves in the power frames (see the leader in Fig. 1).

The mesh surface on each honeycomb section is formed by laying along and across the honeycomb section of radially directed plates, one of which is inserted into the slots of the other plates. In this case, the plate-forming surface of the plate is located on the honeycomb section based on the plate-forming cells of the plate. In FIG. 4, 5 and 6 show the stacking of the plates forming the grid. And in FIG. 7-9 show types of plates forming a grid. One part of the plates 10 for the grid is made in the form of linear flat plates of a rectangular shape with transverse slots (Fig. 4 and 6), the other part of the plates 11 (Fig. 8) is also made in the form of linear flat plates of a rectangular shape with transverse slots, but with This has transversely directed elongations (tongues with bent ends), limited in the body of the plate by small slots on the sides. This is done so that it is possible to put the plate 11 on the wall of the cell 6 in the cell section, bend part of its wall to one side of the cell, and the extension due to small slots is transferred to the other wall of the cell and the bent end of the extension is inserted under the plastic of the cell section (Fig. . 5). This is how these plates are mounted on the honeycomb section. These plates 11 with extensions extend transversely to the honeycomb section and are used to secure longitudinally positioned plates. The third part of the plates 13 (Figs. 4 and 9) basically repeats the design of the plates 11 and is also made with extensions 14 (tongues with bent ends) with bent tips to engage the cell walls of the cell section. It turns out that the cells of the honeycomb structure are square in plan. When the drum rotates and the cell angle of the cell structure changes relative to the vacuum channel diffuser, the air passing through the cell begins to be reflected many times from the walls, thereby creating excessive turbulence. The square shape allows this process to be somewhat minimized, thereby creating a less "torn" air flow, less resistance and, as a result, better distribution of fluff on the mesh surface. The use of this form of honeycomb structure allows to improve the quality of the web laid on the grid.

When laying the plates to fix them on the honeycomb section, part of the transverse and longitudinally arranged plates are made with extensions (tongues) with bent ends for engagement with the plate-forming plates on the back of the cell section. In this case, the principle is used according to which one plate is inserted into the slots of other plates, which allows you to form a spatially stable and connected structure, which part of its plates 10, 11, or 13, or a combination of them fits into the slot 9 of the plates of the honeycomb section and is held on this honeycomb section with the bent ends of the extensions (reeds). Moreover, the design of the mesh or mesh surface of each honeycomb section is highly manufacturable (due to the use of standard elements of three shapes), simplicity and ease of installation and dismantling. And the implementation of the removable mesh surface can greatly reduce the time to replace a worn mesh by replacing the block - the cellular section assembly.

In addition, it is known that for the manufacture of cloths from fibers of different structures and of different origin, it is necessary to regulate and coordinate the volumes of air entering and leaving the molding drum. And this is regulated by the increase or decrease of the mesh surface cells. To increase the size of the cells in the mesh surface of each honeycomb section, it is enough to dismantle part of the plates, while the design of the cell section and the grid on it does not change. The cell size in the honeycomb structure of the frame is initially selected by the largest. These cells are used to pass the maximum possible volume of air and at the same time, the walls of these cells serve only as the basis for strengthening the easily dismantled mesh. And the grid cell sizes are adjusted by adding or reducing the number of plates in the grid structure.

Claims (3)

1. A forming drum for forming a web of short fibers, consisting of at least two ring-shaped power frames located at a distance from each other and interconnected by transverse plate elements located radially and forming a frame together with the power frames to accommodate a circular mesh surface while the mesh surface is formed by laying along and across the honeycomb section of radially directed plates, some of which are inserted into the slots of other plates, I distinguish characterized in that the circumferential mesh surface is made of at least two sections located in the circumferential direction and each of which is located on a separate honeycomb section made in the form of an arched curved frame bounding the honeycomb structure composed of rectangular cells in plan and the mesh surface of the plate is located on the honeycomb section based on the forming cells of the plate, and for fixing the plates on the honeycomb section a part of the transverse and longitudinal The veneered plates are made with tongues with bent ends for engagement with the plates forming the cells on the back of the honeycomb section, with a removable installed mesh for the deposited short fibers placed over each frame. 2. The forming drum according to claim 1, characterized in that the cells of the honeycomb structure are square in plan. 3. The forming drum according to claim 1, characterized in that the mesh removably mounted on top of each frame is attached to the drum by pressing with the help of rods installed in the grooves in the power frames.

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