CS9100817A2 - Method and device for felt of mineral fibres treatment - Google Patents

Description

VVVn-ilY - i -

A method and apparatus for treating mineral fiber felt

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a process for the treatment of felt from mineral fibers in order to reorient the fibers in the felt by gradually changing the felt speed.

The invention further relates to a device for treating mineral fiber felt in order to reorient the fibers in the felt by changing the velocity of the felt during its conveyance.

BACKGROUND OF THE INVENTION Mineral wool products such as glass wool, rock wool or slag wool are well known and used for both thermal and sound insulation.

These products are usually made by melting the raw material, producing mineral melt fibers, for example by feeding them into a spinning unit, which may consist of a series of rotating wheels, entraining the formed fibers from the spinning unit with an air stream and collecting them on the conveyor. in the form of a fibrous felt. The collection may be carried out such that the fibers are deposited on the conveyor to form the desired final thickness, or a so-called primary web is formed by collecting a thin layer of fibers which, for example, is folded by a rocking conveyor to form a secondary web of desired thickness. At a certain stage of manufacture, the felt is impregnated with a suitable binder, for example a resin, which is ultimately cured by heat treatment, for example in a drying furnace, thereby fixing the fibers to form a dimensionally stable, continuous felt of desired density and thickness. It is then felted to the desired shape either as sheets or strips, which are then packaged or processed longer.

When the fibers from the spinning unit are collected into the primary web or into the final felt thickness, they are deposited on the conveyor substantially parallel to the conveyor, which means that only a small portion of the fibers is oriented more or less perpendicular to the plane of the conveyor. This phenomenon is advantageous in some applications because such products have good elastic properties, but in other areas they are a great disadvantage. This felt structure results in poor characteristics of strength in a direction perpendicular to the felt plane, and as a result these products cannot be used in structures that are subject to high mechanical loads, such as floors or loaded ceilings.

One way to achieve sufficient mechanical strength in a direction perpendicular to the felt plane is to increase the volume weight, that is, the density of the felt, which can be accomplished by increasing the amount of fibers or, in some cases, increasing the amount of insolubles. However, the manufacturing cost is directly proportional to the fiber weight, so increasing the strength by increasing the amount of fibers may be unacceptable in some cases.

It is also possible to increase the strength in a direction perpendicular to the felt plane by varying the direction of the fibers in the felt so that a larger portion thereof is arranged in a direction that deviates from the felt. This can be achieved in many ways.

For example, the felt can be cut into tapes having a width corresponding to the desired thickness of the sheet. The tapes are 90 ° folded and glued together to form a so-called lamellar blanket in which the direction of the fibers is predominantly perpendicular to the major surfaces of the sheet. An example of such a method is described in European patent application A 0 000 378. However, such lamellar products must be manufactured on a special post-treatment or processing line, which is associated with additional costs.

It is also possible to produce a planar structure which, in its essential properties, as a lamellar planar structure, without cutting off, in that the fibrous felt is corrugated in an appropriate manner, the corrugated felt compressed to the desired density and cured. Such a process is described in U.S. Pat. No. 1,656,828 (FIG. 6). Also in this article, the direction of the fibers is predominantly perpendicular to the plane. However, the formation of creases on the felt surfaces is associated with disadvantages. In addition to the reduced flexural strength in the longitudinal direction, the folds cause distraction if the panel itself is to be used as an acoustic panel. The thermal insulation performance of lamellar products as well as corrugated products is up to 10% higher compared to conventional sheet-type products. A third method of changing the direction of most of the fibers in the felt is described in German Patent Application No. 16 35 620. According to this method, the speed of the pisti process between two successive conveyors is slowed down, with the rear conveyor running at a lower speed than the previous one when viewed in the direction of travel. conveyor. This braking effect results in longitudinal compression and reorientation of the fibers in the felt, without the formation of creases on the surface. According to this method, both the mechanical and the insulating properties of the end product are good, provided that the degree of compression, i.e. the reduction of the felt velocity during treatment, is maintained below about 20%. the folds appear on the surface. However, this disadvantage can easily be avoided if the process is repeated, i.e. when a number of successive compression steps are performed. This procedure has also been proposed in patent application FI 84 2734.

According to the above-described method, the felt is compressed in the felt zone located in front of the next, slower conveyor extending linearly over the felt width. In this band, the fibers are reoriented in a rather uncontrolled manner and are controlled only by feeding to another conveyor, thereby creating a braking plane for the felt, and possibly guide plates arranged above and below the felt, which plates prevent the acquisition of felt volume more than required . These boards do not participate in the actual reorientation of the fibers. There is no significant compression in the range of the self-contained conveyor, which acts more like a stabilization zone following the ratchet-operated compression. If higher compression is required, it is necessary to use a device which requires a large amount of space, but which does not allow more precise control during the adjustment.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the disadvantages associated with the prior art, in particular the uncontrolled treatment of the felt by several necessarily spaced-apart felt-like areas of the present invention. the consequence of a substantially continually controlled change in felt speed by a single stage treatment that can be easily performed on existing fabrics. This object is achieved by a method of treating the felt of mineral fibers in order to reorient the fibers in the felt by varying the speed of the felt, the change being made by contacting the felt with at least two elements arranged one behind the other in the felt conveying direction, the areas of action of the elements overlap each other

The change of felt speed across all elements is preferably negative, which means that the output velocity of the felt with the last element is lower than its velocity before the first element.

Another object of the invention is to provide a device for carrying out the method according to the invention. This object is achieved by a device for feeding mineral fiber felt to reorient the fibers in the felt by changing the speed of the felt during its conveyance by means of a conveyor device, the conveying device comprising two opposite conveyors, inter alia the fiber felt, each the conveyor comprises at least two shafts which can be driven by different rotational speeds and which comprise means provided to the surface of the felt facing the conveyor, wherein the areas of action of the shafts on the felt overlap one another.

According to a preferred embodiment, the elements of such shape have a mutual arrangement such that the edge edge zone, when the action of one element on the felt is greater than the action of the adjacent element, forms a substantially wavy line extending across the width of the felt.

Preferably, each element consists of two shafts extending across the width of the felt, the shaft being rotated in one direction against the other shaft by means of both sides of the felt. Shafts are provided with means that come into contact with the felt which affect the speed of the felt, which means that depending on the speed of rotation of the shafts with respect to the speed of the web, the bristle or acceleration effect may be applied to the felt, resulting in reorientation of the fibers. The shafts are arranged in such a way that when the felt is conveyed through a plurality of successive elements, the areas of action of the two successive elements on the felt overlap or join. It is believed that this is an overlap with the area of action of the elements, that is, the continuous effect of the elements on the felt, which results in an advantageous final result, as opposed to the impact treatment of the known technique. For a better understanding of the invention, it is conceivable that the portion of the felt being treated is divided into a plurality of bands in which there is a modification or reorientation that extends across the width of the felt. The adjustment zone can be defined as an area where one element has a greater impact on the felt than the adjacent element of the loop. The speed of the felting process just in front of one element is largely controlled by this element, but the effect on the speed then progressively moves to the next element. At some point between these elements, the speed is controlled by more than one element than the other. These more or less theoretical places define Sarah, which is not necessarily straight and which extends across the width of the felt.

Since, in the treatment according to the invention, the area of application of each element overlaps or associates with the area of action of the adjacent element, each section of the felt is always in some adjustment zone where it is exposed to at least one element. In this way, the aforementioned fine structure and gentle reorientation of the fibers in the felt are achieved.

By shaping the elements to form separate areas of contact with the felt in the direction of the felt width, their action is filled not only in the felt transport direction, but also in a direction more or less perpendicular to the felt transport direction, that is to say the direction of the felt. If these contact areas are arranged laterally offset from one another in the felt conveying direction, the boundary between the areas of action between the two elements forms a substantially wavy line, whereby further advantages are achieved. If the felt velocity is different in two successive regions, shear forces are generated in the felt, which are directed both forward and backward, but also towards the edges of the felt. This results in an even more uniform adjustment of the fibrous felt in all its dimensions, thereby giving the article a better flexural strength than could be achieved with the prior art solutions. By varying the size of the contact areas, their relative positions, the compressive forces exerted by the elements on the tray, and the degree of change in felt speed, the adjustment can be accurately controlled in accordance with the desired result.

The salary is preferably treated with a number of elements, for example 4 to 12 elements. According to one embodiment of the invention, the speed of the felt is slowed down over the entire length of the conveying device, preferably slowing down and uniform, which means that the reduction in speed is the same from one to the other and is preferably about 10 to 20%. However, the change in velocity may not be uniform, but may vary in different stages of the treatment. Thus, reducing the speed from one element to another may be smaller at the beginning and greater at the end of the operation, or the speed difference between two consecutive bands may be substantially greater than between the other bands. In this case, the more intensive treatment is preferably carried out in the lateral part of the device. However, it is also possible to increase the speed of the felt in one or more treatment zones, provided that the treatment results in a finished product with diluted fibers. An acceptable article, without creasing, is achieved according to the invention if the felt is subjected to a treatment resulting in varying degrees of compression, but preferably a degree of compression of about 2: 1 to 10: 1, especially 3: 1 to 6, is used : 1, corresponding to a speed reduction of about 50 to 90, in particular 70 to 80%

According to a preferred embodiment, the felt is pre-compressed in a direction perpendicular to the main plane of the felt, prior to treatment, to a thickness less than that of the felt after treatment. Preliminary felts, for example about 70% of the final thickness, and its disintegration during treatment allow for a greater degree of compression, which would result in unevenness in the surface layer and in the inner layer of the felt, i.e. without the so-called filamentary structure of the fiber on the cross section of the article. a problem associated with a high degree of compression according to prior art methods. The shafts in the conveyor can be driven at different rotational speeds, while a pair of shafts, which are formed by mutually spaced shafts in the individual conveyors, are always driven at the same speed but in opposite directions. Advantageously, the shaft carries a plurality of means arranged on the shaft spaced apart, said means being directed on one shaft and extending into the gaps between the means on the adjacent shaft. In one embodiment, the means on one shaft of one conveyor with the corresponding means form a second conveyor belt for the felt, but may also point to the gaps between the means on the other conveyor.

Preferably, the conveying device comprises 4 to 12 shafts in each roller conveyor, thus forming the same number of shaft pairs. The felt-contacting means may be of any suitable shape; for example, they may be in the form of patches, needles, plates, ribs or the like, or may be formed as short, endless, conveyor belts arranged spaced across the width of the felt and extending in the direction of transport in the longitudinal direction of the felt and may bear to increase the heat, such as nails or the like - 10 -

In order to be able to adapt the device to the production of a variety of products, it is advantageous to provide the shafts with means for independent variation of the rotation speed of the shafts. Driving Compound Construction It is well known to those skilled in the art.

In addition, the conveyors may be provided with means known per se for adjusting the distance between them and / or their inclination. Since, in such cases, the adjustment may be made while pressing or expanding the batten thickness, the fiber reorientation conditions may be adjusted longer and the treatment may therefore be adapted to a very diverse variety of articles. The distance and / or degree of inclination may also be varied along the length of the conveying device. BRIEF DESCRIPTION OF THE DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view of a fibrous felt manufacturing apparatus comprising a tuft conditioning device according to the invention; FIG. 2 is a schematic side view of a cooperating roller conveyor forming a felt fitting apparatus; FIG. a plan view of the principle of the operation of the cooperating roller conveyor shafts; Fig. 5 is a schematic view of a device with a variable distance and slope between the conveyors, and Figs. 7a to 7d show different profiles of a device formed by a pair of shafts, as seen in the direction of the felt; the speed of the felt during its transport by the transport device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The treatment of a felted felt, which is fed from the spinning unit (not shown) in the form of a primary felt 1, is composed schematically in FIG. 1. This secondary felt 3 is then inserted between the two. cylinders 4, 4) which pre-compress it in a direction perpendicular to the felt plane In the nip of the rolls 4, 4, the felt 3 is compressed to a thickness which is less than the thickness of the treatment, preferably to about 70% of the final thickness of the web. For this purpose, the felt 3 is introduced into the conveying device by means of suitable guiding means for the purpose of treatment according to the invention. The conveying device is indicated as a whole by the reference numeral 8. In the treatment, the felt is conveyed by a drying oven which is indicated by reference numeral. In the drying oven 15, the final product is cured and fixed.

As best seen in FIG. 2, the conveying device 8 comprises top and bottom conveyors 9 and 10, which in the example shown have both camshaft-shaped rollers, each having two opposed camshafts 11 and 11, 12 and 12j, etc., form a pair of camshafts which together form the clamps 11a, 12a, etc., for the felt. According to one preferred embodiment, the speed of the conveyors 9, 10 decreases in the direction of the felt process due to the fact that the pairs of camshafts 11, 11 ", 12, 12 ', etc. rotate gradually with decreasing speed. for example, between 10 and 20 between the two following shafts. In our case, for example, the first two pairs of shafts may have the same rotational speed as the conveyor in front of the conveyor device 8, while the subsequent shafts are gradually reduced in speed as indicated. , and several last shafts of the device 8 may have the same speed as the conveyor in the drying oven.

FIG. 3 is a schematic view in plan view of how the camshafts can be constructed and how they work together in one conveyor. 8 shows the direction of the felt between the shafts indicated by an arrow. Thus, in the illustrated embodiment, each camshaft 16 on the camshaft extends into a gap between two tube discs 162 on an adjacent camshaft. In the illustrated embodiment, the cam discs have a center distance (a) of about 70% of the camshaft disc diameter, with the disc width (b) It is about 30% of the center-to-center distance (a) and the inter-space (c) is about 40-50% of the center-to-center distance (a). Also shown on the picture is 17 on several adjacent cam discs. These clamps 17 between the cam discs in this embodiment result in a substantially linear area of limited dimension, in particular in the transverse direction of the felt, wherein two successive cam disc clamps 17 form a zigzag-to-felt contact area. The treatment element of FIG. 4, viewed in the direction of the felt, comprises a pair of shafts 11, 11 ' having the same speed of rotation and rotating in opposite directions. The solid lines in the figure relate to an embodiment of the invention where the cam discs 16 in each conveyor 9, 10 face each other and form the cams 17. Also shown in the same figure is an alternative dotted line guide where the cam discs 16 in each conveyor 9, 10 do not face one another, but the cam disc in the 13 disc

One shown, which is conveyed by one conveyor, into the interspace (c) between the cam follower and the embodiment of the device intended to contact the felt shown in FIG. 5, which shows a hub mounted on the shaft of the outer circumference provided with a plurality of ribs 18 equally spaced. along its perimeter. In the embodiment schematically shown in Fig. 6, the upper conveyor 9 is divided into two portions 9a, b. The first portion 9a is arranged with an inclination relative to the lower conveyor 10.

The diagrams in Figures 7a-7d show alternative felt velocity profiles during the treatment of the invention. FIG. 7a shows the case where the felt velocity is uniformly reduced on all the elements of the device. On the other hand, Fig. 7b shows the case where the reduction of the speed is smaller in the initial stage of treatment and greater in the end, while Fig. 7c shows the case where the greatest speed deceleration occurs in the middle stage of the treatment. And finally. 7d shows a case where the speed of the felt can also be increased on one or several elements.

Claims (13)

PATEK TOV A method for treating a mineral fiber felt in order to re-adjust the fibers in a felt by varying the speed of the felt, characterized in that the change in velocity of the felt is performed by contacting the felt with at least two layers arranged one behind the other in the felt conveying direction, the effects of the elements overlap each other by The method of claim 1, wherein the felt velocity is reduced in such a manner that the ratio of velocities at the start of treatment to the end-of-treatment rate is about 2: 1 to about 10: 1, preferably about 3: 1 to about 10: 1. about 6: 1. 3. Method according to claim 1 or 2, characterized in that the boundary where the action of one element overlaps the action of the adjacent element is formed by a substantially wavy line extending across the width of the web. Method according to claim 3, characterized in that the contact between the felt and one of the elements is limited to a plurality of spaced apart contact areas arranged over the felt width, wherein the areas of contact of the felt with the following elements are offset from one another. Method according to any one of the preceding claims, characterized in that the thickness of the plies is gradually changed during the treatment. - 15 - Method according to one of the preceding claims, characterized in that the speed of the felt is gradually reduced during the treatment, with a reduction of the speed between two successive elements of 10 to 20%. 7. A device for treating a mineral fiber felt in order to reorient the fibers in the felt by changing the speed of the felt during its conveyance by means of a conveying device, characterized in that the conveying device (8) comprises two opposite conveyors (9, 10) , between the yarns (3), the liner felt can be conveyed, each conveyor (9; 10) comprising at least two shafts (11, 12 and 11, 12) which can be driven at different rotational speeds and which comprise means (16) brought into contacting the felt surface (3) facing the conveyor (9; 10) in question, overlapping the action areas of the shafts (11, 12 and 11 ', 12') on the felt (3). Apparatus according to claim 7, characterized in that the shafts (11, 12, 11) carry a plurality of separate means (16), the means (16) facing and extending into the intermediate space (c) of the shaft (11; 12) between means (16, 16 **) on an adjacent shaft (11 *; 12 ') of the same conveyor (9; 10). Device according to claim 8, characterized in that the means (16) on one shaft (11) of the conveyor (9) are directed against the corresponding means (16) on the 16 opposite shaft (11 ') of the second conveyor (10), thereby forming a feather (17) for the felt. Device according to claim 8, characterized in that the means (16) on one shaft (11) of the single conveyor (9) are directed into the interspace (c) between the corresponding means (16 *) on the opposite shaft (11 ') of the second conveyor (10). Apparatus according to one of Claims 7 to 10, characterized in that the felt-contact means (16, 16 ', 16 ") (3) comprise pins, vanes, cam discs, endless belt conveyors or the like, which may be friction-enhancing features. Device according to one of Claims 7 to 11, characterized in that the shafts (11, 12, 11 ', 12 *) in each conveyor (9, 10) are provided with means of independently varying the rotation speed of the shafts (11, 12). , 11 ', 12'). Apparatus according to one of Claims 7 to 12, characterized in that the conveyors (9, 10) are provided with means for adjusting the distance and / or relative inclination between the conveyors (9, 10), which means allow for a distance change and / or mutual inclination along the length of the transport device (8). - 17 - Apparatus according to any one of claims 7 to 13, characterized in that. that it comprises a felt pressing device (4, 4 ') in front of the conveying device (4, 4 ') which is smaller than the felt thickness after treatment. Representative: Z 3190