Packing and/or transport unit for insulation slabs of mineral wool and method and device for manufacturing such

Abstract

 The invention concerns a method and a device for manufacturing a packing and/or transport unit for insulation slabs made of mineral wool, in which a number of mineral wool slabs are arranged next to each other with their main surfaces against each other and packed in a wrapper that keeps them in a compressed state, whereby a cohesive bundle of mineral wool slabs is obtained. The mineral wool slabs to be packed in the same wrapping are selected from amongst mineral wool slabs having substantially the same initial thickness and initial density. Of these selected slabs, at least the slabs that will come in the middle of the bundle are precompressed and then packed together with all other slabs in the wrapper so that all the slabs in the bundle at the time of removal of the wrapper after storage and/or transport in the compressed state have essentially the same final thickness and final density. The invention relates also to a packing and/or transport unit for insulation slabs of mineral wool packed in a wrapper that keeps them together in a compressed state.

Description

Object of the invention

[0001] The present invention relates to a method for manufacturing a packing and/or transport unit for insulation slabs of mineral wool, in which a number of mineral wool slabs are arranged next to each other with the main surfaces against each other and packed in a wrapper that keeps them in a compressed state, whereby a cohesive bundle of mineral wool slabs is obtained.

[0002] The present invention also relates to a packing and/or transport unit for insulation slabs of mineral wool, in which a number of mineral wool slabs are arranged next to each other with the main surfaces against each other and packed in a wrapper that keeps them in a compressed state so that they form a cohesive bundle of mineral wool slabs.

[0003] The present invention also concerns a device for performing the method of the invention.

Prior art

[0004] Mineral wool is manufactured by melting compound stone material in a coke or electric furnace. Liquid stone is fed to a spinning machine that makes the melt into cooled fibre while simultaneously different substances are added to the fibre. The fibre mass is collected on a collecting conveyor and carried to a pendulum that oscillates out the collected primary fibre mat to a so-called secondary mat, which is fed into a curing furnace. Sometimes the secondary mat can be pre-treated in a number of ways before curing.

[0005] The mat is led in a continuous stream through the curing furnace where the fibre mass is locked into a desired structure suitable for the respective product types. At the same time the cured mat is given a desired thickness. The slabs are formatted from the cured mat later in the process.

[0006] The process leading up to the cured mat is relatively stochastic. Natural variations in raw materials, processing materials, the condition of the process line, etc. makes the consistence of the cured mineral wool mat vary. In the factories one often talks about the production line's "day condition" or "instantaneous condition". Although one often knows or can deduce the causes of deviations, it is virtually impossible to avoid variations.

[0007] It is common in the manufacture of packing and/or transport units for insulation slabs of mineral wool to arrange a specified number of mineral wool slabs of substantially the same size and density adjacent to each other with the main surfaces against each other and then pack them in a wrapper, usually plastic, which keeps them in a compressed state whereby a cohesive bundle of mineral wool slabs is obtained. Depending on the dimensions of the slabs to be packed, the number of slabs in the package varies from for example three thick slabs to, for example, 20 thin slabs. Such a wrapped bundle is often already as such the desired packing and/or transport unit.

[0008] A disadvantage of packing and/or transport units produced in the above-described known manner is that the slabs in a bundle forming the packing and/or transport unit under the influence of first the packing machine's (different packing machine types deform more or less) and then the following wrapping's compressing force being affected differently over time so that they get different dimensions and densities. At least the two outermost slabs in the bundle, i.e. the undermost and the topmost slabs when the slabs in the bundle are viewed horizontally oriented with respect to their main surfaces, over time assume a clearly smaller thickness and thus higher density than the other slabs in the bundle. In addition, there is also a clear deformation of especially the two outer slabs. When the number of slabs in the bundle is greater, more than one outer slab can be subjected to deformation. This disadvantage means that in the worst case the customer cannot make use of the two outermost slabs for the same insulating object as the other slabs in the package and/or transport unit as deformations of the slabs can lead to uneven joints between the mineral wool slabs and poor thickness filling and thereby to heat leakage in the object to be insulated.

[0009] There is therefore a need to ensure as uniform a quality as possible of the mineral wool slabs that are stored and/or transported packed in wrappers that press the slabs against each other.

Description of the invention

[0010] With the intention to eliminate or at least reduce the disadvantages of the prior art the method according to the invention is characterized in that the mineral wool slabs to be packed in the same wrapper to form a bundle are selected amongst mineral wool slabs having essentially the same initial thickness and initial density and that of these selected slabs that/those slab/slabs that is/are to be placed in the middle of the bundle before they are packed together with all the other slabs are precompressed flat to a predetermined degree with respect to their thickness and then decompressed to an intermediate thickness which is less than the initial thickness, but greater than the thickness of the slab when it is in the precompressed state in the plane press so that at the time of packing the slabs in the said wrapper are of higher density and less thickness than the slabs to be placed outermost in the bundle so that at the time of removal of the wrapper after storage and/or transport in the compressed state all the slabs are of essentially the same final thickness and density.

[0011] In an advantageous embodiment of the method the ratio between the number of not precompressed/decompressed outer slabs and the number of precompressed/decompressed inner slabs in the bundle is 4:16-2:1 before they are packed in wrappers for storage in a compressed state (Example 1: In a package with a total of three slabs the two outermost slabs are not precompressed/decompressed. Example 2: In a package of eight slabs either the two or four outermost slabs can be not precompressed/decompressed. Example 3: In a package with a total of 20 slabs, the either four or eight outermost slabs can be not precompressed/decompressed. The thickness of the package in all these examples is e.g. 800 mm). Since the outermost slabs in the compressed state inside the bundle during packing and storage are compressed more than the inner slabs, this disadvantage can with this approach be compensated so that the slabs when taken into use have substantially the same outer dimensions and density. This means that the outermost slabs need not be produced with overstrong structure since they are not precompressed (whereby the structure is at least to some extent irreversibly destroyed). This in turn means that the method in its entirety will be economically more advantageous because it requires less binder. A further advantage of reduced binder content is also that the fire-resistance increases.

[0012] The degree of precompression and decompression is preferably substantially similar in all the inner slabs exposed to the precompression and decompression. The degree of precompression/decompression can also take into account the production line's day condition or instantaneous condition.

[0013] Compression and decompression occurs primarily through at least one continuous plane press with adjustable precompression and decompression force arranged between the formatting and packing unit. It is especially advantageous to measure the necessary precompression and decompression to ensure as consistent a quality as possible in size and density of all slabs with respect to the time of removal of the wrapping after storage and/or transportation.

[0014] It should be noted that precompression and decompression usually only take place in parallel (thus the location and time should be reserved on the production line). The slab, that also can be a combination slab (cut in the middle), goes into the precompression/decompression/testing unit, stops, is tested/precompressed, held at pressure a preset time, decompressed, moved on and the same process is repeated. Under particularly favourable production conditions the slabs can pass non-stop during the testing/precompression step. Therefore a stop is not necessary. This is product dependent.

[0015] The package and/or transport unit for insulation slabs of mineral wool according to the invention is for its part characterized in that the mineral wool slabs in the bundle are selected from amongst mineral wool slabs having substantially the same initial thickness and initial density and in that of these selected slabs at least the slabs that are placed in the middle of the bundle before being packed with all the other slabs in the bundle have been precompressed flat to a predetermined degree with respect to their thickness and then decompressed to an intermediate thickness less than the initial thickness but greater than the thickness of the slab when it is in the precompressed state so that at the time of packing of the said wrapper they are of higher density and less thickness than the slabs that are placed outermost in the bundle, so that at the time of removal of the wrapping after storage and/or transport in the compressed state all the slabs in the bundle have reached essentially the same final thickness and final density.

[0016] In a particularly advantageous embodiment of the packing and/or transport unit according to the invention all the slabs in the bundle except the outermost ones are precompressed and decompressed to a higher density before wrapping for storage in a compressed state. The degree of precompression and thus also the density after said precompression and decompression is preferably substantially the same in all the inner slabs exposed to said precompression and decompression.

[0017] The device according to the invention which is suitable for carrying out the method of the invention includes at least one means for adjustable plane precompression and decompression of selected mineral wool slabs.

[0018] In an advantageous embodiment of the device according to the invention the means for precompression and decompression consists of a continuous plane press. The said means for precompression and decompression is preferably also connected to or comprises in itself an instrument for measuring the necessary compression force in the form of the product's resistance to pressure ("wave function"). In this way continuous quality control with regard to pressure resistance is obtained. The pressure resistance also says something about the instantaneous condition of the day and this information can be used for production line management. The said means for precompression and decompression is preferably located between the formatting and stacking unit, e.g. in connection with the stacker.

Detailed description of the invention

[0019] The invention is described below in greater detail with reference to
Figure 1 where an advantageous embodiment of a device according to invention is depicted schematically.

[0020] Plane precompression, in this document also referred to as "plane compression", can be used for quality monitoring. Before plane compression of slabs it is useful (a must) to take account of the treatment(s) that the slab has undergone before it reaches its final location where it insulates. Examples of such treatments are the packing, transport, transport duration and installation.

[0021] While the middle slabs are plane compressed to optimal dimensions, optimal density information for both production line management back into the process and forward to the packing is obtained.

[0022] Feedback from the compression force says something about the product pressure resistance and can be used for production line adjustment settings such as density settings, structural changes, binder changes, curing efficiency and so on.

[0023] Feed forward from the compression force can be used to set the packing machines for milder/harder slab and package treatment with respect to the final insulation slab.

[0024] Thus, although the primary function of plane compression is to treat the said inner slabs, it provides additional information for evaluation of what should have been done previously on the production line and what can be done after plane compression, with regard to the "day condition" and "instantaneous condition".

[0025] It is also possible to use plane compression on said outermost slabs, with the intention of compensating for special deviations in the slab's consistency caused by the day condition and instantaneous condition. This compensation is used primarily to give the slabs normal installation properties. Thus, an appropriate consistency is "restored" with plane compression/plane decompression (once or in shocks) (vibrations).

[0026] For quality monitoring a plane precompressor, in this document also referred to as a "plane press", can also be used for slabs other than low density products to be compressed in their packages.

[0027] Also hard/medium hard slab's pressure resistance can be continuously monitored and feedback to production line management can be given.

[0028] Figure 1 is a principle sketch of a continuous plane press intended to be used for precompression/decompression of insulation slabs 2 of mineral wool such as stone wool slabs. The plane press can also be integrated with/in a slab stacker, whereby the method differs, several slabs can then e.g. be pressed simultaneously for different packages. In this example, the plane press 1 is positioned following a formatting unit (not presented in the figure) where an already cured mineral wool mat with essentially consistent quality concerning dimensions and density is cut into equal sized pieces into mineral wool slabs 2 having substantially the same dimensions and density.

[0029] From the formatting unit the slabs are transported further on a conveyor 3 until they arrive downstream of the formatting unit at the continuous plane press 1 with an adjustable degree of precompression (0-100%) (given as "adjustable precompression %" in Figure 1). In the pre-press 1 precompression of all mineral wool slabs 2 (e.g. Paroc's UNS-R slabs) in addition to the slabs that will be outermost, i.e. undermost and topmost, takes place in each individual package and/or transport unit of mineral wool slabs. In this application the expression "the slabs that will come outmost" refers to at least the two outermost slabs, i.e. the very topmost and very undermost slab in a package. In some cases the expression "the slabs that will come outermost" refers to more than two slabs, such as the top two and the lowest two and so on. As the number of slabs grows and/or the slabs are thinner, the number of outer slabs that do not need precompression/decompression increases.

[0030] The flat prepress can be programmed so that it for each slab 2" that passes through precompresses/pre-decompresses by being lowered to a predetermined compression degree and then raised to a non-compressing position so that the precompressed slab is decompressed (slab 2' is decompressed). In compression mode the conveyor belt 3 stops momentarily or the slabs 2 (and 2" and 2') move at constant speed on the production line's conveyor belt. In the latter case, the plane press consists of an endless belt 4 with a flat part 5 which is intended to pre-compress specific slabs 2 against the conveyor belt 3 on which the slabs are transported forward to a stacker (not drawn in the figure). The endless belt 4 is then in the flat part 5 with the same speed and direction as the conveyor belt 3.

[0031] An individual package and/or transport unit can for example include eight mineral wool slabs of which the six innermost slabs are compressed and decompressed (slabs 2') to the same degree, e.g. with 20% compression, whereby the consistency of those slabs is changed so that they become thinner and also get a higher density than the slabs that are not subjected to compression/decompression (slabs 2 that in other words have 0% compression). The compression/decompression treatment means that the structure the cured binder has formed in the mineral wool is changed ("broken") because some of the bonds break and some of the fibres break. With the plane compression/plane decompression method this means homogenization of the consistency that depending on the day condition varies and simultaneously the thickness of the slab is reduced, which should be considered. The pre-press, i.e. the plane compression machine can be programmed so that for example in this specific example, with eight slabs it automatically alternately does not compress two consecutive slabs and pre-compresses and decompresses six consecutive slabs to the same degree. Of the two not precompressed consecutive slabs the first slab will be the topmost slab in one package and the second slab will be the undermost slab in the following package. The prepress is preferably also connected to or comprises in itself an instrument for measuring the necessary compression force ("wave function") (referred to as "measurement of the necessary force" in Figure 1). In this way continuous control of quality with respect to resistance to pressure is obtained.

[0032] Downstream of the prepress 1 a stacker (not drawn in the figure) is arranged where the desired number, e.g. eight, successive slabs are stacked on top of each other in a stack, which is then wrapped in a plastic wrapper the compressive effect of which holds together the eight slabs in a bundle where thus the uppermost and lowermost slabs are non-compressed. The plastic packing can either be carried out with appropriate packing devices arranged directly in connection with the stacker or downstream of the stacker after transport on additional conveyor belts to the packing devices. The package can be made by any techniques known to those skilled in the art.

[0033] In other words, at the time of packing in said wrapping the six innermost slabs 2' in the bundle (which in this example also as such constitutes the package and/or transport unit itself) are thinner and have a higher density than the two outmost slabs 2 in the bundle, i.e. the undermost and the topmost slab, so that the pack's all eight slabs at a later point in time when the wrapping is removed after storage and/or transportation have obtained essentially the same dimensions and density.

[0034] If identical slabs are packed, as was common practice in the prior art, the outer ones become heaviest, i.e. get a higher density, as they are squeezed further in the package while the inner slabs are not significantly squeezed together with respect of the outermost slabs.

[0035] In this example that describes an advantageous embodiment of the present invention the six innermost slabs 2' are precompressed, that is plane compressed, but not the two outermost slabs 2. Of course the two outermost slabs as well as the other six slabs are squeezed after they are packed. This squeezing or compression (i.e. compacting) of the packed two outermost slabs is less than the precompression, i.e. the plane compression of the inner slabs but continues over a longer period of time. The inner slabs are thus squeezed or precompressed more for a short time before packing. The end result is that all eight slabs in the package and/or transport unit are compressed, but that at the time of removal of the wrapping after storage and/or transport they have substantially the same dimensions and density.

Claims

1. Method for the manufacture of a packing and/or transport unit for insulation slabs made of mineral wool, in which a number of mineral wool slabs are arranged next to each other with the main surfaces against each other, and packed in a wrapper that keeps them in a compressed state, whereby a cohesive bundle of mineral wool slabs is obtained, characterized in that the mineral wool slabs to be packed in the same wrapper to form a bundle are selected amongst mineral wool slabs with substantially the same initial thickness and initial density and that of these selected slabs at least that or those slabs that is/are to come in the middle of the bundle before they are packed together with all other slabs in the bundle are precompressed flat to a predetermined degree with respect to their thickness and then decompressed to an intermediate thickness that is smaller than the initial thickness but greater than the thickness of the slabs when they are in the precompressed condition in the plane press so that they at the time of packing in the said wrapper are of higher density and lesser thickness than the slabs that are placed outermost in the bundle so that all of the slabs in the bundle at the time of removal of the wrapping after storage and/or transport in a compressed state have essentially the same final thickness and final density.

2. Method according to claim 1, characterized in that the ratio between the number of not precompressed/decompressed outer slabs and the number of precompressed/decompressed inner slabs in the bundle is 4:16-2:1.

3. Method according to claim 1 or 2, characterized in that the degree of precompression is essentially the same in all said inner slabs exposed to said precompression and decompression.

4. Method according to claim 3, characterized in that the precompression and decompression is done by at least one continuous plane press with adjustable compression force, arranged between the formatting and packing device.

5. Method according to claim 4, characterized in that the necessary precompression is continuously measured to ensure as consistent quality as possible of all the slabs with respect of the time of removal of the wrapping after storage and/or transport in a compressed state.

6. Method according to claim 5, characterized in that feedback from the compression force in the form of product pressure resistance is used for the settings of the production line such as density settings, structural changes, changes in binder composition and/or curing efficiency.

7. Method according to claim 1, characterized in that the feedback from the precompression force in the form of the product's pressure resistance also is used in the outermost slabs for compensation of special defects in the slab consistency caused by the day condition/instantaneous condition.

8. Method according to claim 5, 6 or 7, characterized in that the feed forward from the precompression force in the form of the product pressure resistance is used to set the packing machines to milder or tougher slab/pack treatment with respect to the final insulation slab.

9. Package and/or transport unit for insulation slabs of mineral wool in which a number of mineral wool slabs are arranged next to each other with their main surfaces against each other and packed in a wrapper that keeps them in a compressed state so that they form a cohesive bundle of mineral wool slabs, characterized by the mineral wool slabs in the bundle being selected from mineral wool slabs having essentially the same initial thickness and initial density and that of these selected slabs at least that or those slabs being placed in the middle of the bundle before being packed together with all the other slabs in the bundle being plane precompressed to a pre-specified degree with respect to their thickness and then decompressed to an intermediate thickness which is less than the initial thickness, but greater than the thickness of the slab when it is in the precompressed state so that at the time of packing in the wrapping they are of higher density and lesser thickness than the slabs that are positioned outermost in the bundle so that all the slabs in the bundle at the time of removal of the wrapping after storage and/or transport in a compressed state have reached essentially the same final thickness and final density.

10. Package and/or transport unit according to claim 9, characterized by all the slabs in the bundle except the two outermost ones being precompressed to a higher density before packing in a wrapper for storage and/or transport in the compressed state.

11. Package and/or transport unit according to claim 9 or 10, characterized by the ratio between the number of not precompressed/decompressed outer slabs and the number of precompressed/decompressed inner slabs in the bundle being 4:16-2:1.

12. Package and/or transport unit according to claims 9, 10 or 11, characterized by the degree of precompression and thus also the density after said compression and decompression being essentially the same for all said inner slabs exposed to said compression and decompression.

13. Device for performing the method according to any of the claims 1-8, in which device is included at least one means for adjustable plane precompression and decompression of selected mineral wool slabs.

14. Device according to claim 13, where the said means for compression and decompression consists of a continuous plane press.

15. Device according to claim 14 in which said means for compression and decompression is connected to or as itself comprises a quality monitoring instrument for measurement of the required compression force in the form of product pressure resistance.

16. Device according to any of claims 13-15, where the means for precompression and decompression is located between the formatting and stacking facilities.

Drawing