WO2006040054A1

WO2006040054A1 - Method and device for producing an element made of fibrous insulating material

Info

Publication number: WO2006040054A1
Application number: PCT/EP2005/010720
Authority: WO
Inventors: Gerd-Rüdiger Klose
Original assignee: Deutsche Rockwool Mineralwoll Gmbh & Co. Ohg
Priority date: 2004-10-07
Filing date: 2005-10-05
Publication date: 2006-04-20
Also published as: DE102005044772A1

Abstract

The invention concerns a method and device for producing an element made of fibrous insulating material, in particular mineral fibers, preferably rock wool, said element made of insulating material having two mutually spaced apart and mutually parallel large surfaces, and two lateral surfaces oriented perpendicular to the conveying direction and liking the large surfaces, the fibers being oriented substantially perpendicular to the large surfaces. One primary fibrous strip is deposited, in meanders and in loops, in the form of a secondary fibrous strip, the loops forming ridges which are oriented, in the element made of insulating material, along their longitudinal axis, substantially parallel to the normal lines of the large surfaces. The invention aims at obtaining a method for making better use of possible reserves of resistance of the fibrous strips, so as to produce economically, perpendicular to the large surfaces of said elements, elements made of insulating material with high compression strength and/or high perpendicular tensile strength. Therefor, the invention is characterized in that at least the lateral surface (12) of the element made of insulating material (1) located outside the secondary fibrous strip (2) and oriented towards the protruding primary fibrous strip (2), is subjected at least during the formation of the meanders of the loops (3), preferably more or less over its entire surface, to a pressure oriented perpendicular to the normal lines of the large surfaces (6) of the element made of insulating material (1).

Description

Method and device for producing an insulating element made of fibers

The invention relates to a method for producing an insulating element from fibers, in particular from mineral fibers, preferably from rock wool, wherein the insulating element has two large, spaced and essentially parallel surfaces and two lateral surfaces oriented transversely to a conveying direction and connecting the large surfaces and wherein the fibers are oriented essentially at right angles to the large surfaces, in which a primary fiber web is meanderingly deposited in loops as a secondary fiber web, the loops forming webs which in the insulating material element have their longitudinal axis essentially parallel to the surface ¬ be aligned normal of the large surfaces. Furthermore, the invention relates to a device for producing an insulation element from fibers, in particular from mineral fibers, preferably from rock wool, wherein the insulation element has two large surfaces spaced apart and essentially parallel to one another and two surfaces oriented transversely to a conveying direction and which has side surfaces connecting large surfaces and the fibers are oriented essentially at right angles to the large surfaces, with a pendulum device which meanders a primary fiber web in loops as a secondary fiber web, the loops forming webs which are essentially in the insulating element with their longitudinal axis are aligned parallel to the surface normal of the large surfaces.

Heat and or sound insulation materials are made from different materials. In addition to rigid foams, fibers and fiber materials produced from them represent the main starting material for heat and / or sound insulation materials. Among the insulation materials made of fiber materials, heat and / or sound insulation materials made from mineral fibers represent an important group in this technical area.

Insulation materials made of mineral fibers are commercially differentiated into glass wool and stone wool insulation materials. Stone wool insulation materials have a higher temperature peraturbeständigkeit out, they usually reach a melting point of 1000 ⁰ C to DIN 4102 Part 17. Thus, below Schlackenwolle- insulation materials as well as hybrid fibers of the group of stone wool insulation zu¬ be expected.

Stone wool insulation materials are made from silicate melts which contain high levels of alkaline earths in addition to significant amounts of iron and aluminum oxides. The reshaping into mineral fibers is usually carried out with the aid of powerful multi-wheel fiberizing machines, which are located at the entrance to a collecting chamber, at the opposite end of which an air-permeable conveyor belt or a corresponding drum conveyor is arranged.

With the help of a fan, large amounts of air as cooling and conveying means are sucked past the defibration machine through the collecting chamber and the conveying devices and released into the outside air via cleaning systems. With the help of this air flow, the mineral fibers formed are transported away from their place of origin and deposited as a more or less closed impregnated primary fiber web.

Multi-wheel fiberizing machines usually have four rollers that are staggered. The hollow rollers rotate at high speeds around horizontal hollow axes. The hot melt is passed one after the other onto the jackets of the four rollers. The first roller merely serves to catch a melt jet, which is round due to the cohesive forces, to accelerate it and to pull it out into a thin layer.

Under the effect of the centrifugal force, drops separate from the melts adhering to the rolls and are transformed into mineral fibers or non-fibrous particles with the participation of the air which is bypassed peripherally past the roll shells. The formation of mineral fibers on the first roller is undesirable, but it occurs regularly without special measures being taken to impregnate it with binders. Serve as a binder predominantly thermosetting mixtures of phenol, formaldehyde-urea resins, to which small amounts of adhesion-promoting substances such as silanes are added. Additions of polysaccharides to these resin mixtures have also been tried and tested in practice. The use of the binders mentioned by way of example has the advantage that they dissolve in water or at least disperse colloidally and can then be distributed well in the fiber mass.

The binder solutions or dispersions are introduced into the fiber-forming space through the hollow shafts of the last three rolls and additionally through nozzles arranged peripherally on the calf circumferences. Together with the binders, additives such as hydrophobizing and mostly also dust-binding substances can also be transported and fed into the fiber-forming space. Mineral oils that are not miscible with water are extracted in this way.

The almost explosive evaporation and the corresponding distribution of the water lead to sufficient cooling of the mineral fibers formed. The binders and additives are dispersed in the finest droplets. The binders are now deposited on the mineral fibers as a viscous, sticky mass.

The proportions of binder in the insulation elements are varied between approximately 2 to approximately 4.5% by mass or between approximately 6 to 8% by mass, depending on the manufacturing process used. Since the average fiber diameter is approx. 6 to 8 μm and the fiber lengths are less than 1 cm, it is obvious that only a part of the mineral fibers is ideally connected to one or more mineral fibers via a droplet of binder. Higher proportions of binders are generally forbidden because the contents of organic components endanger the desired classification as non-combustible building materials in the sense of DIN 4102 Part 1. Furthermore, a stronger bond reduces the free mobility of the individual mineral fibers, which reduces the elastic-resilient behavior of the insulation element or favors its brittleness. Last but not least, the binding medium represents a considerable cost factor, the losses also increasing disproportionately with larger specific amounts used.

The proportion of additives is on average around 0.2% by mass, so the mass is only sufficient to form films a few nanometers thick on the individual mineral fibers.

The moisture content in the fiber mass is low. On the one hand, this prevents the binders from running in the course of the further process steps or accumulating significantly in the outer zones during later curing, and last but not least, energy is saved during drying.

The high specific output of each of the three fiber-forming rollers of up to 21 melts per hour leads directly to interactions between the mineral fibers in the form of agglomerations of the mineral fibers more strongly impregnated with binders and additives, which in turn now form the central areas of flakes . The less bound mineral fibers hook onto these central agglomerations, while completely unbound mineral fibers, although mostly impregnated with additives, form their own flakes.

Individual mineral fibers, like ultimately also the flakes, tend to be oriented in the direction of flow in the high, albeit turbulent, flows directly around the defibration machine and also in the course of the trajectory through the collecting chamber. The flakes flowed around on all sides, although loosely connected to one another, are slightly rounded off.

Larger non-fibrous particles are often spherical and, due to their mass and shape, are carried to the outside and either collide with the defibration machines at a short distance from the boundary walls of the collecting chamber, where they lose part of their energy and down from the mass. fall out. Smaller particles initially follow the fiber mass in their trajectory. With the loss of kinetic energy, however, they fall down and are thus separated from the actual fiber mass flow. However, this still contains, in terms of size, 30% by mass of non-fibrous particles with small diameters <125 μm.

Mineral fibers enriched with binders also strike the walls of the collecting chamber and stick there or increase in size due to the stickiness until they are torn off due to their own weight and shape. These flat structures are easily entrained in the air flow and thus reach the fiber mass flow.

Of importance are net-like structures made of binder-free mineral fibers, which are created primarily on the first roller. Because of their open shapes and their low masses, they usually move above the fiber mass flow at a significantly lower speed. They will later become clearly visible in the fibrous web and the insulation elements made from the fiber mass, which is mostly brownish-colored due to the organic binders, due to their lack of coloration as white layers or inclusions, and are also responsible for considerable reductions in the mechanical strength of the insulation elements.

Further inhomogeneities in the collected fiber webs also result from the fact that longer mineral fibers adhere to the walls, in which non-fibrous particles get caught, the structures detach and thereby get into the fiber mass flow.

The fiber mass impregnated with binding agents and additives is collected in various ways and brought together to form fiber webs. In the previously predominant direct collection, the fiber mass flow was directed to a slowly running conveyor device arranged in the same direction. This conveyor is usually located below the level of the defibration machine. The width of the collecting chamber and that of the conveyor correspond to the width of the fiber web plus a small surcharge. With the constant fiber mass flow, the conveying speed is controlled with regard to the desired bulk density and the thickness of the insulating material elements to be produced therefrom. Under the effect of the air sucked through the conveying device, the more or less coherent flakes lay flat on top of one another and thereby form a filter itself, the resistance of which increases with the thickness of the fiber web deposited; the density of the fiber web is hardly changed. As the air resistance increases, the suction effect of the air flow decreases, which favors a free alignment of the falling flakes. The primary fiber web formed in this way is relatively inhomogeneous in the direction of all three spatial axes.

The primary fiber web is then pressed together by rollers or belts in the vertical direction to the desired thickness and thus also to the required bulk density.

The fiber web is then passed between the pressure belts of a hardening furnace. In this oven, hot air is simultaneously passed in a vertical direction through the fiber web so that it is heated up sufficiently within a short time, the moisture evaporates and the binder is cured and thus solidified.

The fibrous web leaving the hardening furnace can be referred to as an endless insulation web, which is trimmed along its side faces and then divided into individual insulation boards as insulation elements. Greater lengths can also be cut to length from the endless insulating material web, which are then wound up and wrapped in film.

In the insulation elements obtained from this, the mineral fibers are aligned essentially parallel to the large surfaces of the insulation elements. There is no preferred orientation of the individual mineral fibers with respect to the two horizontal spatial axes or it is so little developed that there is no significant anisotropy of the mechanical properties. However, in order to be able to produce pressure-resistant roof insulation panels with an initial strength of more than 40 kPa at 10% compression in this structure, bulk densities of more than approx. 180 kg / m ^{3 are} required. The transverse tensile strength at right angles to the large surfaces nevertheless remains low, especially since accumulations of binder-free mineral fibers act like separating layers.

Due to the significantly increased performance of the fiberizing machines and the combination of two or three fiberizing machines with only one collecting chamber or production line, only a thin as possible primary fiber web with basis weights of only 100-200 g / m ² , but with very high conveying speeds subtracted up to approx. 7 m / s. The widths of these fiber webs are between approx. 1.8 m to approx. 4 m.

The primary fiber webs are then deposited with the help of a reciprocating device in loops across on another air-permeable and now significantly slower conveying device, which mostly consists of roller conveyors with a drive system. Fiber webs of any width can be formed via the amplitudes of the pendulum movements and due to the length of the device.

The loops placed one after the other in a meandering manner are slightly offset and one above the other in an inclined direction to the conveying direction. Inhomogeneities in the primary fiber web are thus distributed more evenly in the secondary fiber web. However, the fiber flakes and thus also the individual mineral fibers are preferably oriented transversely to the new conveying direction. The connections between the mineral fibers are significantly more intensive in this direction than at right angles to them. The rounded edges of the flakes are accordingly oriented transversely to the conveying direction. The bulk density of the secondary fiber web is only insignificantly higher than the bulk density of the primary fiber web during the collection, despite the load due to its own weight without additional processing. The mineral fibers therefore only form a loose structure. In the area of the large surfaces of the secondary fiber web, as a result of the high conveying speeds and the pendulum movements, the moisture content in the fiber surface as well as the stickiness of the binders is slightly reduced. Areas with unbound mineral fibers are located between the individual loops of the fiber web.

In order to produce insulating material elements which can be subjected to pressure and have a reduced dead weight, the loops of the secondary fiber web are first compressed and unfolded and at the same time folded. The loops are unfolded and unfolded by a continuous horizontal compression of the fiber web in the conveying direction in a ratio of approximately 2: 1 to 3.5: 1 and by a continuous compression in the vertical direction of approximately 2: 1 up to approx. 3: 1. In order to transmit the forces required for the compression processes, the secondary fiber web is first conveyed by two roller tracks running towards one another and compressed and compressed in the vertical direction. Only now can the forces required for horizontal compression be transferred from the outside to the inside.

After this folding process, many mineral fibers lie, in particular in the area of the large surfaces and the areas below, parallel to the large surfaces of the secondary fiber web.

A secondary fiber web of this type does not have a sufficiently high compressive strength and the transverse tensile strength perpendicular to the large surfaces is also low.

Crosswise to the horizontal fold, the mineral fibers are predominantly oriented at right angles to the side surfaces of the secondary fiber web, so that the secondary fiber web has great compressive and transverse tensile strengths in this direction.

By separating the secondary fiber web into slices parallel to the horizontal compression direction, so-called lamella plates are formed. DE 197 34 532 A1 describes the continuous production of an endless

Insulation sheet described, in which the mineral fibers are oriented at least in a core area predominantly at right angles to the large surfaces. This insulating material web is produced from a directly collected primary fiber web with flat mineral fibers by first angling the primary fiber web by 90 degrees, so that the mineral fibers are essentially aligned vertically. Subsequently, sections with a length are separated from this fibrous web, which either correspond to the maximum throughput height of a hardening furnace of at most approx. 200 mm or a smaller insulation thickness. The individual sections are then put together again to form a closed secondary fiber web.

The bending over of the primary fiber web leads to a compression in the area of the inner large surface and to a tensile stress of the mineral fibers in the area of the outer surface. The separated section therefore has different bulk densities in both surface areas. Due to the short lengths of the sections, the procedure can be carried out quickly, which, among other things, leads to a large number of weak connections between the individual sections of the secondary fiber web or the insulation element formed therefrom. If the individual sections of the secondary fiber web are to be pressed against one another by compression devices acting from the outside, the mineral fibers are stored flat in the large surfaces and the areas arranged underneath, thereby preventing the desired improvement in the mechanical properties ¬ these areas near the surface remain in the secondary fiber web.

In the method described above, it is also disadvantageous that the individual sections are not designed identically, so that the individual sections have to be reworked, in particular re-cut. The economy of the previously known method is therefore questionable.

US Pat. No. 5,981,024 describes a process for the production of an endless sheet of insulating material which, in principle, is based on the continuous unfolding of each because there are only two primary fiber webs placed transversely offset on one another on a conveyor. Due to high conveyor speeds, the angle between the edge areas of the two fiber webs is small.

The width of the deposited secondary fiber web depends on the exactness of the control of the pendulum device. The aim is not to make the width of the secondary fiber web substantially larger than the width of the insulating material elements to be produced therefrom, in order to keep the material losses to a minimum by trimming both edge areas, but on the other hand to form self-contained side faces.

The secondary fiber web is then conveyed into a device consisting of two conveyor belts arranged one above the other, between which the secondary fiber web is compressed. The compression associated therewith improves the connection of the primary fiber webs and stiffens the secondary fiber web for subsequent unfolding, so that the unfolded layers do not collapse. For example, two primary fiber webs each weighing 700 g / m ^{2 can form} a secondary fiber web with approximately 60 kg / m ³ .

The secondary fiber web is then fed to a directly adjoining conveyor which oscillates about a horizontal transverse axis. The oscillating movements cause the secondary fiber web to unfold continuously. A major weak point in this unfolding of the secondary fiber web is the pendulum device used. Only in appearance does this not differ in principle from the first pendulum device that is used for transverse laying of the primary fiber web, although the two conveyor belts are not next to each other but one above the other are arranged and are also driven by deflection rollers located at the end. These deflecting rollers are moved back and forth on a section of a circular path in the case of the pen device, which is pivoted about a fixed pivot point.

A thin fibrous web with rapid pendulum movements and yet with exact side edges offset one above the other on a horizontal conveyor belt laying is described in WO 88 03 121. As one of the solutions described there, the pendulum device is made displaceable in the pivot point with the aid of guides and guide rollers. The pendulum device is moved in the areas of the two reversal points in each case away from a support surface in order to reduce the influence of the heavily braked and then accelerated in the opposite direction on the fiber web guided out at a consistently high speed and to achieve the desired exact To achieve alignment of the side edges.

The guiding of the fiber web can furthermore be achieved by the reciprocal jumping back and forth of the conveyor belt of the pendulum device, respectively, which is described in US Pat. No. 5,007,623.

The loops, which are ideally arranged loosely one behind the other, are pushed unchanged by the frictional forces of two conveyor belts acting on the large surfaces of a conveyor device driven at a reduced conveying speed, so that the upright loops are now pushed towards one another in the longitudinal direction of the secondary fiber web. The height of the unfolded secondary fiber web remains unchanged, so that in order to be able to transmit sufficient shear forces, the loops must again be compressed and compressed vertically.

The structure of a tertiary fiber web formed in this way is then fixed by solidifying a binder in a hardening furnace by means of hot air. After trimming the two outer edges of the tertiary fiber web, this forms an endless insulation web that can be divided into individual insulation boards.

This insulation web is constructed in longitudinal section as an at least three-layer structure which, with a completely symmetrical design with respect to the horizontal central axis, has a ribbon-like arrangement of the mineral fibers in the core areas predominantly at right angles to the large surfaces. In the upper and lower deflection areas, the pre-compressed primary fiber webs and with them the mineral fibers are arranged even with completely uniform unfolding with increasingly flatter angles to the large surfaces.

In addition, the rigid primary or secondary fiber web is pulled down when the pendulum device moves downward or tilts back slightly under the effect of gravity. The height of the folds is also clearly limited, since the loops, for example due to the sagging of individual sections, cannot form stable shapes due to different stiffnesses, and this can result in at least inclined positions of the areas of the fiber web that are up to the point where the loops collapse.

In order to be able to produce insulation elements with higher bulk densities and corresponding strengths that can withstand pressure and / or tension, considerable forces must be transmitted over the outer areas of the secondary fiber web. The action of the corresponding pressure and thrust forces regularly results in a secondary loop formation.

Because of the unsafe formation of loops in the upper region of the secondary fiber web, the loops there are preferably tilted against the conveying direction.

While lamella panels with an average bulk density of approx. 70 kg / m ³ in laboratory tests easily have transverse tensile strengths of approx. 80 to approx. 100 kPa, the strength level of the insulation elements manufactured according to the above-described methods is more than approx. 30% below.

On the basis of the prior art described above, the invention is based on the object of providing a method and a device with which or with the possible strength reserves of fiber webs can be better used to insulate elements with high compressive strengths and / or ho- hen transverse tensile strengths at right angles to the large surfaces of the insulating elements economically.

The solution to this problem in a method according to the invention provides that at least the side surface of the insulation element which is external in the secondary fiber web and faces the feed of the primary fiber web, at least during the meandering formation of the loops, preferably over almost its entire surface a pressure perpendicular to the surface normal of the large surfaces of the insulating element is applied.

On the part of the device according to the invention it is provided as a solution that the pendulum device is followed by a pressure device which preferably covers at least the side surface of the insulation element that is located outside in the secondary fiber web and faces the feed of the primary fiber web, at least during the meandering formation of the loops, preferably over almost its entire surface presses against the previously formed loop with a pressure oriented at right angles to the surface normal of the large surfaces of the insulating element.

The invention is based on the consideration of aligning the mineral fibers in a position that is as steep as possible with respect to the large surfaces and thereby significantly reducing the proportion of flat or flat-inclined fibers or these parts of the secondary fiber web with regard to improving the mechanical strengths to use.

Accordingly, it is provided in the method according to the invention that primary fiber web is produced by directly collecting fibers impregnated with binding agents and preferably additives. However, the starting point can also be a fiber web that is produced by superimposing thin primary fiber webs across the conveying direction. In particular, however, the primary fiber web is placed on top of one another in an oscillating manner in the conveying device. The single The fibers or the flakes formed from them are thus oriented in the same direction.

The amplitudes of the pendulum fiber webs should be as large as possible in order to keep the number of transverse folds in the secondary fiber web as low as possible.

The primary fiber web consisting of one or more layers lying one above the other can subsequently be compressed by a device known per se in order to increase the rigidity and thus the stability and the pressure resistance of the upright loops to be formed subsequently. Furthermore, the tightest possible bending of the fiber webs in the transition areas can be achieved, so that a loop formation with cavities lying in the loops is avoided. As a result, the loops aligned at right angles to the large surfaces can be pressed close together. However, the compression should not exceed the desired bulk density of the insulation element by more than approximately 15%.

A compression device required for the compression can be arranged obliquely to the conveying direction, for example in order to convey the primary fiber web directly into a neutral plane of an unfolding device.

According to the invention, a pendulum device can be arranged between the compression device and the unfolding device.

The unfolding device essentially consists of a stable holding device which is moved in an oscillating manner in accordance with the desired height of the secondary fiber web and the throughput.

The primary fiber web is guided in and through the unfolding device by, for example, oscillating roller sets. The distance between the roller sets is variable. Their conveying speed is set in such a way that the primary fiber web is subjected to a slight tensile stress. The maxi- Male elongation is less than 20%, preferably <10%. As a result of the stretching, the fibers are additionally aligned and the uniformity of the secondary fiber web or the strength of the insulating material elements produced from the secondary fiber web is increased.

The pendulum movement of the roller sets preferably runs in the opposite direction to the oscillating movement of the holding device.

In addition, the roller sets, or at least the feed rollers of the unfolding device, can be displaced relative to one another, so that when the unfolding device moves downward as an example, the lower feed roller, the lower roller set or any lower conveyor device designed in the direction of the secondary fiber web is pushed to press the loops together. Similarly, an upper infeed roller, the lower roller set or any lower conveyor can be moved in whole or in part in the opposite direction.

In addition to the guide rollers, the unfolding device can have further pressure elements. These are generally driven in the same direction with the respective guide roller and prevent the loops of the secondary fiber webs from falling back, in particular widening of the deflection regions to form less compressed or open loops.

The pressure elements are guided above and below the loops of the secondary fiber web to be set up so that they always remain in contact with the secondary fiber web which is to be set up and compressed, taking into account the oscillating movements of the unfolding device.

According to a further feature of the invention, the pressure elements are designed as rollers, which are extended individually with the aid of linear motors, for example in the form of lifting devices, in order, for example, to individually compress a side surface of the secondary fiber web that is set up depending on the position of the unfolding device can. The in the conspicuous According to a further feature of the invention, pressure elements arranged on the outside can be extended further in order to compress the deflection areas of the secondary fiber web more than the central areas of the side surface of the secondary fiber web. Furthermore, the loops in the two outer zones of the secondary fiber web can be fixed in the desired position by this further development.

The loops of the secondary fiber web can thus be compressed differently over the height and the width of the side face. The compression of the two outer areas of the side surface reduces the risk that fibers are pressed between the loops that are set up and thereby expand the secondary fiber web. In this way, insulation elements can be produced with at least one surface zone that is denser than the core.

The pressure elements can also be adjusted as a whole depending on the direction of movement of the unfolding device. In this case, for example, the lower pressure element can be pushed forward in the direction of the side surface of the secondary fiber web, in order, for example, to press the lower part of the loops of the secondary fiber web set up and to hold it in the desired position when the unfolding device moves upward. In this position of the lower pressure elements, the upper pressure elements are at a distance from the side surface of the secondary fiber web and lead a next loop of the primary fiber web to the side surface of the secondary fiber web. This procedure treats the fiber web gently, so that unwanted shearing or even tearing of the fiber web is avoided.

The rollers shown here by way of example can have profiled outer lateral surfaces, which are formed, for example, by strips arranged on the outer lateral surfaces or offset from one another and formed by sheepskin-like compression elements. This profiling is suitable for making the individual loops of the secondary fiber web slightly wavy. The unimpeded deflection of the primary fiber web is very important for the mode of operation of the unfolding device. A conveying device preferably connected downstream of the unfolding device consists, for example, of two roller conveyors or conveyor belts arranged opposite one another, the spacing of which can be adjusted in order to compress the secondary fibrous web in the direction of the surface normal of the large surfaces.

The conveying device must also be designed in such a way that deflection of the entire secondary fiber web upwards or downwards is avoided.

The upper and lower rollers of the pressure elements are preferably resiliently mounted individually or in sets connected to one another in order to enable the loops of the secondary fiber web to be adjusted and pressed on. A further development provides that the rollers or comparable pressure elements are designed with pressure-controlled lifting devices. The position of the loops of the secondary fiber web which have been set up can be detected with the aid of sensors and counteracted in the event of undesired deflections.

The compression of the secondary fiber web in its longitudinal axis or conveying direction by the pressure elements can be supported and supplemented by moving the two roller conveyors or conveyor belts of the downstream conveying device together.

If a further compression of the secondary fiber web in its longitudinal axis or conveying direction is aimed for, the secondary fiber web can be compressed in a slower running conveyor.

According to a further feature of the invention, it is provided that horizontal saws are arranged in front of a hardening furnace, with each of which a relief cut is made along boundary layers between the areas, namely deflection areas with oblique or parallel to the large surfaces of the secondary fiber web Fibers and the core area of the secondary fibrous web is carried out in which the fibers are aligned at right angles to the large surfaces. According to a further feature of the invention, the layer separated off remains in situ and is hardened in the hardening furnace and connected to the core area of the secondary fiber web.

In order to produce insulation elements with higher transverse tensile strengths, lower material losses in an economical manner, it can be provided that the layers with the fibers running obliquely and / or parallel to the large surfaces of the secondary fiber web are separated and removed.

The separated layers can, for example, be brought together and used for the production of insulation boards or other shaped bodies with corresponding bulk densities.

Alternatively, the separated layers can be fed to the production process of the fibers or placed transversely or lengthways on the primary fiber web on a second conveyor. The merged fiber webs are then connected to one another in a compression device. In order to improve this bond, contact surfaces can be sprayed beforehand with a binder or impregnated in another suitable manner.

However, the separated layers can also be comminuted again and added to the fiber mass flow via the collecting chamber.

It is also possible to separate only one layer from the surface of the secondary fiber web and to utilize it in one of the ways described above and to leave the second layer in situ. In this way, insulation boards can be produced which have a high transverse tensile strength in relation to the large surface and a pressure-equalizing layer in relation to the other large surfaces. Insulation boards constructed in this way are suitable, for example, for the manufacture of composite thermal insulation systems. With regard to the method according to the invention, reference is again made to the following advantageous configurations:

In a further development of the method it is provided that the primary fiber web is compressed in the direction of its normal surfaces of its large surfaces before the meandering formation of the loops, so that the webs with a low height and high mechanical strength values are formed, which can be arranged in narrow deflection areas in the secondary fiber web.

According to a further feature of this development, it is provided that the primary fiber web is compressed up to a bulk density increase of up to 15% of an initial bulk density of the primary fiber web.

It has proven to be advantageous to alternately lay down the primary fiber web as a secondary fiber web in order to form a uniform secondary fiber web.

For gentle conveying and a continuous process, it has also proven to be advantageous for the secondary fiber web to be deposited on a conveying device.

According to a further feature of the invention, it is provided that the secondary fiber web is compressed in the region of the conveyor device in the direction of the surface normal of the large surfaces of the insulation element. In this way, a smooth surface and an improvement in the mechanical properties are achieved in a simple manner.

In order to align the fibers in the desired direction, it is provided that the primary fiber web is preferably stretched in its longitudinal direction immediately before the meandering formation of the loops. It has proven to be advantageous here that the expansion is carried out by increasing the conveying speed before the meandering formation of the loops.

In order to reduce the risk of the primary fiber web tearing, a further feature of the invention provides that the elongation is limited to a change in length of at most 20%, in particular at most 10%, of the initial length of the primary fiber web.

A further development of the method according to the invention provides that the side surface of the insulation element which is external in the secondary fiber web and faces the feed of the primary fiber web is pressurized by means of a pressure device which can be moved essentially parallel to the surface normal of the large surfaces of the insulation element.

The secondary nonwoven fabric is preferably formed by moving the pressure device in opposite directions to oscillate the primary fiber web.

The properties of the insulation element can be adjusted in a particularly advantageous manner by the pressure on the side surface lying outside in the secondary fiber web and facing the feed of the primary fiber web depending on features, in particular a desired bulk density of the insulation element is set.

According to a further feature of the invention, it is provided that the pressure on the side surface lying outside in the secondary fiber web and facing the feed of the primary fiber web is exerted differently over the side surface, for example greater in deflection regions than in a central region of the side surface.

A simple increase in bulk density takes place in that the secondary fiber web is compressed in its longitudinal axis direction. This also complements the individual loops are pushed towards one another and connected to one another.

A further development of the method according to the invention provides that the fibers arranged in the area of at least one large surface of the insulation element and not oriented at right angles to the large surfaces are removed, in particular by cutting and / or grinding, in order to create an insulation element with high compressive and / or transverse tensile strength to train.

In order to fix the properties of the insulation element, it is provided that the secondary fiber web is fed by means of a hardening furnace for the hardening of a binder connecting the fibers.

It can be provided that the secondary fiber web is fed to the hardening furnace after the fibers that are not at right angles to the large surfaces of the insulating element are removed.

A further development of the method according to the invention provides that the fibers which do not run at right angles to the large surfaces of the insulating element are cut off as at least one fiber layer by at least one cut parallel to the large surfaces.

The cut fiber layer is preferably conveyed through the curing oven together with the secondary fiber web. The cut fiber layer is thereby fixed and can be processed into further products.

Alternatively, it can be provided that the cut fiber layer is connected to the secondary fiber web after the binder has hardened, in particular in the hardening furnace.

Another possibility for treating the cut fiber layer is that the cut fiber layer is removed and used to form a secondary product used, in particular combined with at least one further fiber layer and connected.

There is also the possibility that the cut fiber layer is removed and fed together with the primary fiber web to the meandering formation of the loops.

Of course, it can also be provided that the cut fiber layer is removed, comminuted and fed to a defibration unit, in particular a melting unit for forming fibers.

Further features and advantages of the invention result from the following description of the associated drawing, in which a section of a device according to the invention is shown.

In the figure, a section of a device for producing an insulating element 1 from mineral fibers is shown. The insulation element 1 consists of a secondary fiber web 2, which is arranged in a meandering manner in loops 3, the loops 3 being formed with a pendulum device 4 from a primary fiber web 5.

The insulation element 1 or the secondary fiber web 2 have two large surfaces 6 arranged opposite one another, the loops 3 forming webs 7, the longitudinal axis of which are oriented at right angles to the large surfaces 6. In the webs 7 there is a course of the mineral fibers at right angles to the large surfaces 6. Only in edge areas directly below the large surfaces 6 does a portion of the mineral fibers run obliquely or parallel to the large surfaces 6. These areas result from the deflection of the primary fiber web 5 and are therefore also referred to as deflection areas.

The pendulum device 4 consists of a roller conveyor with two roller tracks 8, each having a plurality of rollers 9, the roller tracks 8 of the pendulum Device 4 are adjustable relative to one another in order to exert pressure on the large surfaces 10 of the primary fiber web 5 and to compress the primary fiber web 5.

In addition, the device has a pressure device 11 which is connected downstream of the pendulum device 4 and which at least has the side surface 12 of the insulating element 1 which is at the outside in the secondary fiber web 2 and faces the feed of the primary fiber web 5 at least during the meandering formation of the Loops 3 preferably press against the previously formed loop 3 over approximately their entire surface with a pressure oriented at right angles to the surface normal of the large surfaces 6 of the insulation element 1.

The pressure device 11 has a large number of pressure elements 13, each of which in the present exemplary embodiment consists of a roller 14 and a linear motor 15. The roller 14 can be moved to the side surface 12 via the linear motor 15, the required pressure being transmitted to the side surface 12 via the roller 14.

For this purpose, it is provided that the linear motors 15 are at least partially resilient in order to ensure that the rollers 14 are in constant contact with the side surface 12. Via the linear motors 15, differently high pressures can also be transmitted to surface areas of the side surface 12, for example in order to achieve a higher compression of the secondary fiber web 2 in the deflection areas.

The pressure elements 13 are arranged on an oscillatingly movable holding device 16, the holding device 16 executing a direction of movement parallel to the surface normal of the large surfaces 6 of the insulation element 1 or the large surfaces 10 of the primary fiber web 5. Here, an opposing movement of the pendulum device 4 to the holding device 16 is provided. Accordingly, the holding device 16 moves downward when the pendulum device 4 swings upward. The pressing device 11 is followed by a conveyor device 17 for the secondary fiber web 2, the conveyor device 17 consisting of two roller conveyors 18 arranged opposite one another and adjustable in their spacing from one another, each having a multiplicity of rollers 19.

Not shown in the drawing is a hardening furnace downstream of the conveying device 17, to which the secondary fiber web 2 is fed in order to harden a binder binding the fibers of the secondary fiber web 2 by passing hot air through the secondary fiber web 2. In addition, the hardening furnace (not shown in more detail) can be preceded by a cutting device (not shown in more detail) with which partial areas of the secondary fiber web 2 are cut off immediately below the large surfaces 6 parallel to the large surfaces 6 in order to remove the areas with mineral fibers in which the Mineral fibers parallel or oblique, at least not at right angles to the large surfaces 6.

With the device described above, a method for producing an insulating element 1 from mineral fibers can be carried out, in which the primary fiber web 5 is compressed in a pendulum device 4 between two roller tracks 8 and then arranged in an oscillating manner in loops 3 to form the secondary fiber web 2. The loops 3 form webs 7 in which the mineral fibers are aligned at right angles to the large surfaces 6 of the secondary fiber web 2. Adjacent webs 7 are connected to one another via deflection regions in which the mineral fibers are oriented obliquely or parallel to the large surfaces 6 of the secondary fiber web 2.

The pendulum device 4 is combined with the pressure device 11. The pressure device 11 has the holding device 16 with the pressure elements 13 arranged thereon and is moved up and down parallel to the surface normal of the large surfaces 6 of the secondary fiber web 2 or the large surfaces 10 of the primary fiber web 5. Here are the rolls 14 pressure elements 13 formed on the last loop 3 of the secondary fiber web 2. With further rollers 14, the loop 3 to be laid is pressed onto the previously laid loop 3 in order to achieve a tightest possible bond in the secondary fiber web 2.

The primary fiber web 5 is compressed in the shuttle device 4 between the roller webs 8 to a bulk density which is 10% higher than the initial bulk density of the primary fiber web 5.

In addition, it is provided that a conveyor device upstream of the pendulum device 4 and not shown has a lower conveying speed than the pendulum device 4, so that the primary fiber web 5 in the pendulum device 4 is additionally stretched. An expansion to a change in length of 5% of the initial length of the primary fiber web 5 is provided.

In the same way, it is provided that the conveyor device 17 connected downstream of the pressure device 11 has a lower conveying speed on the output side than on the input side, so that the secondary fiber web 2 is smoothed both in the area of its large surfaces 6 and is compressed in the longitudinal axis direction.

The invention described above is not limited to the exemplary embodiment. In addition to mineral fibers, the method according to the invention can also be carried out in connection with organic fiber material, although it is of course particularly suitable for the production of insulation elements from mineral fibers, in particular from rock wool and / or glass wool. The insulating material web produced with this process can be described as endless, since it is only interrupted by interrupting the fiber melting process. A suitably designed endless insulation sheet can then be divided into insulation panels. Longer sections with a length of, for example, 2 to 6 m can alternatively be wound and packed in an enveloping film. The use of the insulation elements designed in this way extends over the entire area of thermal and / or acoustic insulation, in particular in buildings, the insulation elements being usable both in the roof area and in the facade area or for interior insulation in the area of walls, ceilings and floors. Due to the different design options of the insulation elements with or without the described layers with mineral fibers arranged obliquely and / or parallel to the large surfaces 6, use in the flat roof area as a walkable insulation layer or also in composite thermal insulation systems is possible.

Claims

Expectations

1. A method for producing an insulating element from fibers, in particular from mineral fibers, preferably from rock wool, wherein the insulating element has two large, spaced and essentially parallel surfaces and two lateral surfaces oriented transversely to a conveying direction and connecting the large surfaces and wherein the fibers are oriented essentially at right angles to the large surfaces, in which a primary fiber web is meandered in loops as a secondary fiber web, the loops forming webs which are in the insulating element with their longitudinal axis essentially parallel to the

Surface normals of the large surfaces are aligned, characterized in that at least the side surface (12) of the insulation element (1) which is external in the secondary fiber web (2) and faces the feed of the primary fiber web (5), at least during the meandering formation of the

Loops (3) are preferably acted on over almost their entire surface with a pressure oriented perpendicular to the surface normal of the large surfaces (6) of the insulation element (1).

2. The method according to claim 1, characterized in that the primary fiber web (5) before the meandering formation of the loops (3) is compressed in the direction of their surface normal of their large surfaces (10).

3. The method according to claim 2, characterized in that the bulk density of the primary fiber web (5) is increased by up to 15%, for example by compression of the primary fiber web (5).

4. The method according to claim 1, characterized in that the primary fiber web (5) is laid down in an oscillating manner as a secondary fiber web (2).

5. The method according to claim 1, characterized in that the secondary fiber web (2) is deposited on a conveyor (17).

6. The method according to claim 1, characterized in that the secondary fiber web (2) in the region of the conveyor (17) in

Direction of the surface normal of the large surfaces (6) of the insulation element (1) is compressed.

7. The method according to claim 1, characterized in that the primary fiber web (5) is preferably stretched in its longitudinal direction immediately before the meandering formation of the loops (3).

8. The method according to claim 7, characterized in that the stretching is carried out by increasing the conveying speed before the meandering formation of the loops (3).

9. The method according to claim 7, characterized in that the elongation is limited to a change in length of at most 20%, in particular at most 10% of the initial length of the primary fiber web (5).

10. The method according to claim 1, characterized in that the side surface (12) of the insulation element (1) which is external in the secondary fiber web (2) and faces the feed of the primary fiber web (5) has an essentially parallel to the surface normal of the large surfaces (6) of the insulation element (1 ) movable pressure device (11) is pressurized.

11. The method according to claim 10, characterized in that the pressure device (11) is moved in opposite directions to oscillate the primary fiber web (5).

12. The method according to claim 1, characterized in that the pressure on the outer in the secondary fiber web (2) and the feed of the primary fiber web (5) facing side surface (12) depending on features, in particular a desired bulk density of the

Insulation element (1) is set.

13. The method according to claim 1, characterized in that the pressure on the outer surface in the secondary fiber web (2) and the feed of the primary fiber web (5) facing side surface (12) via the side surface (12) different, for example in deflection areas greater than is exercised in a central region of the side surface (12).

14. The method according to claim 1, characterized in that the secondary fiber web (2) is compressed in its longitudinal axis direction.

15. The method according to claim 1, characterized in that the fibers arranged in the area of at least one large surface (6) of the insulating element (1) and not aligned at right angles to the large surfaces (6) are removed in particular by cutting and / or grinding.

16. The method according to claim 1, characterized in that the secondary fiber web (2) is fed to a curing oven for curing a binder connecting the fibers.

17. The method according to claims 15 and 16, characterized in that the secondary fiber web (2) after removal of the non-perpendicular to the large surfaces (6) of the insulating element (1) fibers is fed to the hardening furnace.

18. The method according to claim 17, characterized in that the fibers which do not run at right angles to the large surfaces (6) of the insulating element (1) are cut off as at least one fiber layer by at least one cut parallel to the large surfaces (6) .

19. The method according to claim 18, characterized in that the cut fiber layer is conveyed together with the secondary fiber web (2) through the curing oven.

20. The method according to claim 18 or 19, characterized in that the cut fiber layer after curing of the binder, in particular in the curing oven with the secondary fiber web (2) is connected.

21. The method according to claim 18, characterized in that the cut fiber layer is removed and used to form a secondary product, in particular is brought together and connected to at least one further fiber layer.

22. The method according to claim 18, characterized in that the cut fiber layer is removed and together with the primary fiber web (5) is fed to the meandering formation of the loops (3).

23. The method according to claim 1, characterized in that the cut fiber layer is removed, shredded and fed to a chamfering unit, in particular a melting unit for forming fibers.

24. Device for producing an insulating material element from fibers, in particular from mineral fibers, preferably from rock wool, the insulating material element being two large, spaced and essentially parallel to each other and two surfaces oriented transversely to a conveying direction and the large Has surface-connecting side faces and wherein the fibers are oriented essentially at right angles to the large surfaces, with a pendulum device that meanders a primary fiber web in loops as a secondary fiber web, the

Form loops that are aligned in the insulation element with their longitudinal axis essentially parallel to the surface normal of the large surfaces, characterized in that the pendulum device (4) is followed by a pressure device (11) which at least rests in the secondary fiber web (2 ) external and the feed of the primary fiber web (5) facing side surface (12) of the Insulating element (1) at least during the meandering formation of the

Loops (3) preferably press against the previously formed loop (3) over almost their entire surface with a pressure oriented at right angles to the surface normal of the large surfaces (6) of the insulation element (1).

25. The device according to claim 24, characterized in that the pressure device (11) consists of at least two pressure elements (13) which are arranged on both sides of an inlet for the primary fiber web (5).

26. The device according to claim 25, characterized in that the pressure elements (13) are movable relative to the secondary fiber web (2) in the direction of the surface normal of the large surfaces (6) of the insulation element (1).

27. The device according to claim 25, characterized in that the pressure elements (13) relative to the secondary fiber web (2) in

Direction of the longitudinal axis or a conveying direction of the insulation element (1) or the secondary fiber web (2) are movable.

28. The device according to claim 24, characterized in that the pendulum device (4) has an upstream and / or integrated compacting device, which in particular consists of two mutually adjustable conveying devices, for example roller conveyors (8).

29. The device according to claim 25, characterized in that the pressure elements (13) are fastened to a holding device (16) that can oscillate essentially parallel to the side surface (12).

30. The device according to claim 25, characterized in that the pressure elements (13) each consist of a plurality of rollers (14), which in particular individually and preferably with different contact pressure via linear motors (15) relative to the side surface (12) of the secondary Fiber web (2) are adjustable.

31. The device according to claim 24, characterized in that the pressing device (11) is followed by a compression device which exerts a compressive pressure on the large surfaces (6) of the insulating element (1) or the secondary fiber web (2).

32. Apparatus according to claim 31, characterized in that the compression device consists of two conveyor devices which can be adjusted at a distance from one another, for example roller conveyors (18).

33. Device according to claim 25, characterized in that the pressure elements (13) have a profiled surface.

34. Device according to claim 24, characterized in that the pressure device (11) is followed by a hardening furnace in which a binder connecting the fibers is cured.

35. Apparatus according to claim 24, characterized in that the pressing device (11) is followed by a cutting and / or grinding device with which fibers are removed from the large surfaces (6) of the secondary fiber web (2) which are oblique and / or parallel to the large surfaces ( 6) are aligned.