EP0524062B2 - Method for making a load of rolls of compressible materials - Google Patents

Abstract

The subject of the invention is a method for making a load of cylinders of compressible materials, consisting in constituting modules, each formed by a layer of cylinders, in superposing a plurality of modules in a stack, in compressing the assembly of modules thus superposed, in stopping the compression in order to let the assembly relax, optionally in turning the assembly in order to place the cylinders upright, then in placing ties to keep the stack to the dimensions obtained. The invention also relates to the device for implementing this method. <IMAGE>

Description

The present invention relates to packaging compressible materials, and in particular insulating felts of glass wool or other wool mineral, and more specifically aims to achieve palletizable loads of reduced size facilitating transport and storage of such products.

Light fibrous insulating materials are generally packed in the compressed state under the form of rolls closed by unitary packages paper belt or envelope type plastic material, mainly based on polyethylene, heat shrunk. To decrease the cost of transport operations, especially during loading and unloading, and to simplify storage, these rolls are usually assembled in batches on pallets. In practice, the size of these must be compatible with dimensions of the means of transport, trucks or most often, railroad cars. These latter also limit the total height of the palletized load, which must therefore ultimately comply a fairly strict template into which a reduced number of rollers.

On the other hand, and except to surround the burden of rigid panels so as to form cages protectors ensuring the definition of the allocated volume with rollers - solution which obviously failure to significantly increase the cost of load - the rollers must be mounted upright, so that the weight of the rollers constituting the upper layers acts perpendicularly to the radial compressive force exerted during the constitution of the roll. In these conditions, increase the number of rolls per palletized load only seems possible reducing the diameter of the rollers, thus increasing the compression ratio during winding. This solution, already widely implemented work, however is reduced by the compression limit elastic of the material; remember that the insulating capacity of a fibrous material is a function directly of its thickness and that it is therefore no question of accepting any degradation at this level.

It was also proposed in the request of European patent EP-A-275,473 to surround a group of five or nine rolls using a sheet of plastic, to come and style the group thus isolated by means of a suction device which evacuates part of the trapped air between the coiled felt turns and between the rollers. The evacuation of this volume of air allows then bring the rollers closer together, the load being permanently maintained in this state reduced to by means of a wrapping. Such a process involves however a relatively complex installation and especially imposes a second wrapping phase if the batches have to be stacked.

The invention relates to a new solution for compact a load of rollers of material compressible, and in particular of fibrous material insulator, or, of course the same thing, for increase the number of rollers per load, and this while preserving the quality of the material, taking care in particular not to create deformations permanent ones remaining during the unpacking of the rolls, even after a relatively long storage period long, for example a few months.

• constituer des modules formés chacun d'une couche de rouleaux placés côte à côte, les uns au contact des autres,
• superposer plusieurs modules en pile, les rouleaux étant disposés couchés (voir EP-A-220 980 constituant l'art antérieur le plus proche), ledit procédé étant caractérisé par les étapes supplémentaires suivantes :
• comprimer cet ensemble dès modules superposés dans le sens de l'empilement des modules, la compression ramenant l'épaisseur de l'ensemble à une hauteur correspondant à un taux de compression du feutre, constituant le matériau compressible, supérieur au taux de compression correspondant à sa limite élastique,
• arrêter la compression pour laisser se relâcher cet ensemble,
• mettre en place des liens pour maítriser la pile de modules aux dimensions obtenues.

En outre, avant de mettre en place ces liens, on peut tourner la pile à90° de manière à ce que les rouleaux se retrouvent debout.To this end, a method is proposed which consists in rearranging rollers by temporarily applying over-compression. More specifically, the method according to the invention comprises the following steps:

• constitute modules each formed by a layer of rollers placed side by side, one in contact with the other,
• superimpose several modules in a stack, the rollers being arranged lying down (see EP-A-220 980 constituting the closest prior art), said process being characterized by the following additional steps:
• compress this assembly from superimposed modules in the direction of stacking of the modules, the compression reducing the thickness of the assembly to a height corresponding to a compression ratio of the felt, constituting the compressible material, greater than the compression ratio corresponding to its elastic limit,
• stop compression to let this set relax,
• set up links to control the stack of modules to the dimensions obtained.

In addition, before putting these links in place, the stack can be rotated 90 ° so that the rollers are left standing.

Temporary vertical compression can be very important, and in any case correspond to a compression mismatch well above the limit of elastic compression of the material which, remember, is already very strongly compressed during the roll-up phase. The compression can for example temporarily lower the height load at a height between 50 % and 80% of the initial height, the duration of the compression phase being adjusted accordingly, and shorter as the compression temporary exercise is high.

As soon as the compression is interrupted, the rolls regain some of their thickness initial, but only part. Nevertheless, the gain in thickness does not translate into degradation compressible material. The review of rolls shows that in fact this decrease in the load height is not due to new load compression, but rearrangement rollers, which initially formed cylindrical, pass to a parallelepiped shape, shape which leads to a more compact stacking. Surprisingly, it appeared that this parallelepiped shape does absolutely no harm to the quality of the final product, and that the product unpacked does not keep any trace of its packaging.

The stack must be kept to the dimensions obtained after it has relaxed; for that we can use a strapping machine which will places two or three links, for example in terms of plastic. Another solution is to carry out a wrapping with plastic stretch film, the charge then being protected from the weather and can therefore be stored in the open air.

The stack of rollers is preferably limited to three layers, but several charges, two at all least, can be layered before step of setting up links, taking care of course the axes of the rollers are properly aligned to prevent the weight of the upper layers does not degrade the lower layers.

Vertical compression should not be compensated totally by moving the rollers extremes of each layer, also these should they be retained, otherwise compression would chase them aside. To do this, it can be pre-wrapped the stack of rolls before applying compression. A another solution is to belt all the rollers constituting a layer, which presents the advantage of providing modules, for example 4 to 6 rolls, prepackaged so that they can be sold in batches. In this case, the faces rollers are not retained when compression, but on condition that you use a material which has a certain elasticity for belt the roller modules, a fact that does not pose in practice no problem. Furthermore, such thermoplastic belts can contribute to joining together the modules before returning them, this joining being obtained by heating the belts - for example by blowing hot air - during the release of the battery. The modules can also be united with each other by means of glue strips or adhesive tapes.

A device capable of implementing the method according to the invention, includes a stacking station layers of rollers, a compression station vertical, possibly a rotation station 90 ° from the stack, an installation station links and a transporter to move the stack from one post to another.

The compression station can be for example constituted by a pressure plate suspended from the by means of a hoist above a conveyor strip for inserting and removing batteries. Such a compression station can be inserted in an existing packaging line without disruption of it. In another variant, the post compression consists of a hydraulic table lifting the load to come and press it against a fixed flat pressure plate, the table is then substituting for the carrier.

In a more particularly preferred variant of the invention, the pressure plate is not strictly flat but has an extra thickness in its central part, constituting a kind of punch which increases locally and in particular to plumb with the rollers in the middle of each module, compression force. This allows a good alignment of the rollers of the same module which, when fitting the belt, have a certain tendency to have an arc, the roller of the middle playing a role of keystone.

Other details and advantageous features of the invention are described below with reference in the appended figure 1 which represents a diagram in perspective of a compression station of a device according to the invention.

As already indicated, the invention applies to rollers and more particularly rollers of glass wool-based felts. These rollers are for example obtained by operating according to the processes described by the requests for Patent FR-A-2,553,744, EP-A-238,393 or EP-A-294 320, or any other process capable of producing a winding with such uniform compression as possible over the entire length of the strip coiled felt, so as to lead to formation of turns, all of the same thickness, including for the first coils which constitute the core of the roller and also its most brittle.

If adequate precautions are taken at time the felt strip is wrapped over itself, a glass wool felt can withstand compression ratios of 4 or more, which means that the thickness of the wound tape is less than a quarter of the initial thickness, initial thickness which is found when the strip is held. Generally, all rolls are products with identical diameters, whatever either the thickness of the strip, so as to preserve dimensions and weight substantially constant, which simplifies their packaging. Thereafter and to fix the ideas, it will be done reference to a typical roller from 400 mm to 410 mm in diameter and 1200 mm long, but it goes from the process according to the invention can be applied to rollers of different diameters. Of the number of rolls per module or per load and half load can of course be changed and adapted to each particular case without leaving the part of the invention.

In a first step, the rolls wrapped each in a shrink polyethylene film in the heat, or more simply in kraft paper, are associated in modules of five, each module being belted. In a module, the rollers are lying side by side, arranged in the same alignment. This belt is under tension and deforms so the rollers which, from cylindrical, become ovoids, with their largest dimension according to the vertical. Typically, the module has a height of the order of 445 mm and a length of 1495 - 1500 mm, which indicates a slight crushing on the coast.

In a second step, the modules are superimposed, as shown in Figure 1, where schematically a stack made up of three modules 1, of five rollers retained by a belt 2 retracted. Because this belt compresses slightly rollers, upper generators rolls of a given module - or respectively the lower generators - are actually not strictly coplanar but define an arched curve, a roller - most often the central roller - playing a key role. This phenomenon can be annoying to the extent that the more the loads carried are parallelepiped and less will be their size. A shape adapted from the pressure plate according to the invention allows to remedy this problem perfectly as it will be shown later.

The stack of three modules thus formed has therefore a height between 1330 and 1340 mm. It is transported for example by a transporter belt 3 to the compression station. This compressor station is protected by side grids 4, whose role is simply ensuring the safety of line personnel conditioning which can be brought to work on the conveyor belt. The essential organ is a pressure plate 5, here constituted by a block of reinforced concrete weighing 3 tonnes, supported by a metal frame in commercial profiles.

The pressure plate 5 is moved by means a hoist 6 capable of moving the platform to slow or fast speed (e.g. at a speed about 1 m / min at the time of compression and 4 m / min during the approach cycles and platform lift). Hoist 6 is supported by a metal frame 7 which also plays a guide role of the pressure plate 5 provided with a sliding guide system on the posts the frame, and which also supports the transporter with band 3 to compensate for its deformation due to compression forces.

The set also includes a device by locking the pressure plate 5 in the high position, this device being for example constituted by bars 8 on which come abut the heels 9 associated with the pressure plate 5 thus prohibiting his descent. When the system is in service, these bars 8 are separated by a nice 10 manually controlled in the case here represented, but which can also be enslaved in automatic operation by presence detectors of a charge.

The pressure plate 5 has in its part central, facing the rollers in the middle of the pile, an extra thickness forming a kind of punch, which allows to bring flat the different modules.

The stack of three modules in place in the substation compression plate, the pressure plate 5 is lowered and crushes the pile so as to bring its height to a value, for example, between 950 and 1000 mm. Such vertical compression is partially offset by an increase the length of the modules which, depending on the case, reaches 30 to 50 mm. Such compression of rollers, which is added to the compression of the felt made during the winding, is in itself perfectly inadmissible and would lead inevitably significant degradation of the felt, with a loss of thickness recovery, if it was maintained for a period of time relatively long. Nevertheless, it appeared that such degradation does not occur if this time period is short enough. In practice and still in the aforementioned case, this compression is maintained for a period which is not less than 15 seconds nor more than 40 seconds and preferably between 20 and 30 seconds. If we choose to compress again plus the load, for example by means of a tray heavier presser, this compression time will preferably be reduced a little. In the otherwise, it can be extended, although this solution is generally not preferred because it leads to a slower pace of production.

This compression phase completed - and without seek to maintain the charge in such a state of compression by any means of the type strapping, wrapping, ... - the pressure plate 5 went back up and the stack of three modules is thus released. At that time, from made of the elasticity of the material, there is a loosening of the stack which stabilizes for a height between 1200 and 1230 mm, a gain more than 100 mm from the initial height. Examination of the rollers also shows that they do not fully recover their cylindrical shape initial, but tend towards a more parallelepiped shape with a more square section, the gain in height thus being essentially due to the decrease in the empty space between the rollers. Otherwise, the oval deformation of the rollers has practically disappeared, and the stack is more compact.

The battery is then evacuated then rotated 90 ° by a suitable tilting device, so that place the rollers upright. Another identical stack is then formed and, by means of a device gripping, for example of the pliers type, the two piles are placed one on the other on a pallet, ensuring that the rollers of the top row be aligned lower rollers. The charge thus constituted is permanently maintained in good condition by wrapping using a plastic stretch film. This wrapping compensates for a loosening possible a little too important charges, without compressing them more (the rollers expand due to loosening, not swelling, in other words the air evacuated between the rollers during compression does not re-enter in the battery during the expansion phase).

Without changing the final compression ratio of the product, the invention allows to significantly improve the load factor of the means of transport (railway wagons or trucks), the charges being of a reduced bulk.

Note that the invention is in no way limited to the proposed embodiment and that it can be chose different variants: thus, the modules may not be glued but held by a any binding. The battery can also be maintained before the compression by wrapping, which then makes the belts of the modules useless. Finally, the mobile pressure plate can be replaced by a fixed tray associated with a table hydraulic.

Claims (9)

1. Method of producing a batch of rolls of compressible materials, comprising the following stages:

   forming modules, each of which is formed of a layer of rolls, placed side by side, in contact with one another;

   superimposing several modules in a stack, the rolls being disposed in a layered manner, said process being characterised by the following additional stages:

   compressing this assembly of superimposed modules in the direction in which the modules are stacked, the compression bringing the thickness of the assembly to a height which corresponds to a rate of compression of the felt, which constitutes the compressible material, which is greater than the rate of compression corresponding to the elastic limit thereof;

   cessation of compression in order to allow this assembly to expand;

   positioning of ties to control the stack of modules at the dimensions obtained.
2. Method according to Claim 1, characterised in that, prior to the positioning of the ties, said assembly is turned in such a manner as to dispose the rolls in an upright position.
3. Method according to Claim 1 or Claim 2, characterised in that the compression is maintained for a duration which is neither less than 15 seconds nor greater than 40 seconds.
4. Method according to any one of Claims 1 to 3, characterised in that two stacks of rolls are superimposed before the ties are placed in position.
5. Method according to any one of Claims 1 to 4, characterised in that the modules are banded.
6. Method according to Claim 5, characterised in that the stack of modules is rendered rigid by gluing, the bands being heated.
7. Method according to any one of Claims 1 to 4, characterised in that the stack of modules is rendered rigid by a binding.
8. Method according to any one of Claims 1 to 4, characterised in that the stack of modules is provided with a wrapping strip.
9. Method according to one of Claims 1 to 8, characterised in that the force which is exerted is greatest at the centre.

Images