WO2009090303A1

WO2009090303A1 - Method and apparatus for packaging compressed or non- compressed slab-like mineral wool products

Info

Publication number: WO2009090303A1
Application number: PCT/FI2009/050020
Authority: WO
Inventors: Heikki Sallinen
Original assignee: Paroc Oy Ab
Priority date: 2008-01-16
Filing date: 2009-01-14
Publication date: 2009-07-23
Also published as: FI20085034L; FI20085034A0

Abstract

The invention relates to a method and apparatus for packaging slab-like mineral wool products in a packaging material (2). In the method according to the invention, an entity (1) to be packaged, formed by one or more mineral wool slabs, advances along a conveyance line consisting of conveyor elements (3, 4, 7, 8) for wrapping the same in the packaging material, such that, as a result of wrapping, the packaging material (2) is caused to cover the entity (1) of one or more mineral wool slabs over its main surfaces (22, 220 and to extend beyond its edges (20', 21', 23', 24'; 20", 21", 23", 24") sufficiently for enabling the unsupported laps of packaging material, overshooting the edges of the entity formed by one or more mineral wool slabs and coming face-to-face with each other, to be sealed to the attachment with each other. In the invention, those laps (28, 29; 28', 290 of the packaging material (2) coming face-to-face with each other, which overshoot those edges (20', 21'; 20", 21") of the entity (1) formed by one or more mineral wool slabs, which are substantially parallel to an advancing direction (L) of this particular entity (1) of one or more mineral wool slabs, are held on by means of suction at least during the course of sealing the same, whereby the packaging material remains (2) substantially straight in the sealing process.

Description

METHOD AND APPARATUS FOR PACKAGING COMPRESSED OR NON- COMPRESSED SLAB-LIKE MINERAL WOOL PRODUCTS

In one aspect, the invention relates to a method for packaging slab-like mineral wool products in a non-compressed or compressed condition in a packaging material, in which method an entity to be packaged, formed by one or more mineral wool slabs, advances along a conveyance line consisting of conveyor elements for wrapping the same in the packaging material, such that, as a result of wrapping, the packaging material is caused to cover the entity of one or more mineral wool slabs over its main surfaces and to extend beyond its edges sufficiently for enabling the unsupported laps of packaging material, which overshoot the edges of the entity formed by one or more mineral wool slabs and,come to face each other, to be sealed to the attachment with each other.

In a second aspect, the invention relates to an apparatus for packaging slab- like mineral wool products in a non-compressed or compressed condition in a packaging material, said apparatus comprising a conveyance line consisting of conveyor elements, along which each entity to be packaged, formed by one or more mineral wool slabs, advances for wrapping the same in the packaging material, such that, as a result of wrapping, the packaging material is caused to cover the entity over its main surfaces and to extend beyond the entity's edges sufficiently for making the unsupported laps of packaging material overshooting the entity's edges and facing each other capable of being sealed to the attachment with each other by means of sealing devices included in the apparatus.

In this application, the expression "main surfaces of an entity formed by one or more mineral slabs" is used in reference to that surface of an entity, upon which or supported by which the entity advances along a conveyance line, and to the surface parallel thereto on the opposite side. Prior art

Known in the prior art is a horizontal wrapping machine used for packaging mineral wool slabs, wherein a compressed or non-compressed slab-like mineral wool product to be packaged is pushed by means of and between two first belt conveyors of a conveyance line along the line against a plastic wrap section, which lies in a substantially straight and substantially vertical and perpendicular position and whose cross-line width exceeds the cross-line width of a mineral wool slab advancing along the line. When the mineral wool slab to be packaged is pushed by means of said first belt conveyors against the plastic wrap, the latter folds over and thereby covers the mineral wool slab over its main surfaces and extends beyond the edges of the mineral wool slab. The folding of plastic is effected by means of and between two second belt conveyors placed immediately downstream of the first belt conveyors. Once the mineral wool slab's main surfaces have become covered with plastic, the mineral wool slab package has its trailing end sealed up by means of a sealing bar mounted crosswise of the conveyance line. While making this cross-sealing, the same sealing bar produces another parallel and alongside running seal while slitting the plastic wrap between these seals. Hence, the horizontal plastic wraps, dispensed separately from each other by means of conveyor belts from above and below the conveyance line, are rejoined this way for a single integral wrap.

After the crosswise sealing, the next prior art step has been to seal to the attachment with each other those laps of packaging material coming face-to- face with each other, which overshoot those edges of a mineral wool slab which are substantially parallel to the advancing direction of this particular mineral panel along the conveyance line. At this point, a problem regarding the reliability of sealing has arisen in prior art equipment. Before discussing this problem, reference is first made to terminology used in this application. The expression "the end edges of a mineral wool slab"\s used in this application in reference to those edges of each mineral wool slab, which are substantially parallel to the advancing direction of this particular mineral panel along the conveyance line. The expression "the end face of a mineral wool slab" or "the end face of a package" is used in reference to the end faces, which are contiguous to said end edges and which are substantially parallel to the advancing direction of this particular mineral wool slab along the conveyance line.

The unsupported laps of packaging plastic overshooting the end edges of a mineral wool slab present on the conveyance line of a prior art packaging apparatus become easily puckered, whereby the seals do not prove consistent in quality and secure. Efforts have been made to solve these problems by various ways of delivery. A diagonal delivery has been used, which does not work because the plastic crumples and becomes stuck here and there without control. Thus, the plastic arrives at a sealing operation in a multiply condition and the result is a poor (not durable) joint. The packaging material laps overshooting the end edges of a panel, which in this application are also referred to as "end laps", have also been subjected to air blasting in an effort to set the same straight for sealing, but still the plastic seldom enters the sealing operation in a sufficiently straight condition and often remains in multiple folds or otherwise wrinkled, resulting in a poor joint. The end lap slides along metal guide plates to a sealing process. The plastic is always drawn to wrinkles also by friction caused by the metal plates. Hence, these methods have not worked reliably, the resulting joints having been occasionally good, occasionally bad.

Moreover, because of the wrinkling of plastic, the prior art apparatus necessitates the use of extra plastic in an amount sufficient to produce plastic waste, the removal of which is inconvenient. The extra plastic has been cut away in the sealing operation. The prior art apparatus has had its conveyance line flanked by or provided on each side with plastic removal grippers, which take hold of and drop the extra plastic laps into a cardboard box on each side of the apparatus. These grippers or jaws are operated by compression cylinders. Once the grippers have taken hold of the plastic, the jaw member is driven aside by means of pneumatic cylinders, followed by opening the jaws and the plastic falls down into the cardboard boxes. In addition, at present, the sealing bars do not extend to a sufficient closeness to each other in view of running shorter packages (the dimension of packages in a crosswise direction of the conveyance line). It is an objective in the future that the packages be compressed to a thickness of about 250 mm, which currently cannot be managed due to structural aspects of the presently available apparatus.

Description of the invention

It is an object of this invention to provide a method and apparatus for avoiding the foregoing prior art problems.

In order to achieve this, a method according to the invention is characterized in that those laps of packaging material coming face-to-face with each other, which overshoot those edges of the entity formed by one or more mineral wool slabs, which are substantially parallel to an advancing direction of this particular entity of one or more mineral wool slabs, are held on by means of suction at least during the course of sealing the aforesaid laps of packaging material, whereby the packaging material remains substantially straight in the sealing process.

On the other hand, an apparatus according to the invention is characterized in that the apparatus is equipped with suction devices, by means of which those laps of packaging material coming face-to-face with each other, which overshoot those edges of the entity formed by one or more mineral wool slabs, which are substantially parallel to an advancing direction of this particular entity, are held on by the suction devices at least during the course of sealing the aforesaid laps of packaging material, whereby the packaging material remains substantially straight in the sealing process.

In one preferred embodiment for a method of the invention, the sealing processes are conducted while compressing the entity of one or more mineral wool slabs in its perpendicular direction.

In another preferred embodiment for a method of the invention, after the suction-controlled sealing process, extra packaging material is cut off of those two opposite end faces of the entity, which are substantially parallel to the advancing direction of this particular entity formed by one or more mineral wool slabs, by driving the packaged product on the conveyance line against a resistance wire, a laser cutter or the like cutting element, located on each side of the product and the conveyance line conveying the same.

Preferably, the extra cut-off packaging material is removed by suction from both sides into a sack, a bin or the like receptacle. A suitable packaging material is for example plastics, but any other meltable material can be used as well. The packaging material, e.g. plastics, is preferably sealed by fusing its laps facing each other to the attachment with each other. The sealing by fusion is preferably conducted by means of resistances, preferably by means of sealing bars equipped with resistances, by the application of heat, ultrasound or laser, yet most preferably by means of said sealing bars located on the opposite sides of a product to be packaged. Sealing can also be done by heat guns. In order to provide a reliable strength for the joints of a package, it is preferred that at least the product's end faces (20, 21) are provided with a double-sealing joint.

In one particular embodiment for a method of the invention, wherein the entity, formed by one or more mineral wool slabs, has its wrapping in the packaging material conducted on a conveyance line in such a way that the entity to be packaged is pushed in a perpendicularly compressed condition by means of and between the first conveyor elements against a packaging material wrap section present in a substantially straight and preferably vertical or perpendicular position, whereby said packaging wrap, in response to a push-induced displacement of the entity, folds over to cover the entity over its main surfaces and to extend beyond its edges, it is preferred and characteristic that the control by suction is conducted essentially from starting the wrapping at least until finishing the sealing of those laps which are held on by suction.

In the above-described preferred embodiments, the entity to be packaged only consists preferably of one mineral wool slab. If the entity to be packaged consists of more than one mineral wool slabs, these may be e.g. on top of each other, side by side, and/or consecutively with respect to the conveying direction of the line.

In one preferred embodiment for an apparatus of the invention, the suction devices for controlled sealing are provided on each side of a conveyance line, conveying the entity to be packaged, downstream of those sealing devices which are used for sealing up those unsupported laps of packaging material which, in the longitudinal direction thereof, are perpendicular to said advancing direction.

The apparatus has its suction devices comprising preferably two suction belt conveyors, which have the unsupported laps of the packaging material, overshooting the edges of the entity formed by one or more mineral wool slabs, pulled by suction to the attachment with and conveyed between the same in a controlled manner and in a straight condition to the sealing process.

It is also preferred that the controlled sealing be adapted to be conducted by at least those sealing devices, lying on each side of the conveyance line's conveyor elements between each end face of the product and the suction devices associated therewith.

It is particularly preferred that the conveyance line's conveyor elements comprise one or more pairs made up by the belt conveyors, between which the sealing processes are conducted while compressing the entity to be packaged, formed by one or more mineral wool slabs, in a direction perpendicular thereto.

In another preferred embodiment, on each side of the conveyance line conveying the mineral wool slabs, downstream of those sealing devices used for sealing those laps which are substantially parallel to the package advancing direction, the apparatus is provided with a resistance wire, a laser cutter or the like cutting device for cutting extra packaging material off of these two end faces of the package.

The extra cut-off packaging material is removed preferably by suction through a suction pipe system, provided on each side, into a sack, a bin or the like receptacle. Thereby, the removal of resulting plastic waste is facilitated. The sealing devices comprise preferably one or more resistance wires, in response to whose melting effect on the packaging material made of plastics, the laps facing each other are respectively sealable to the attachment with each other by one or more joints.

In one particular preferred embodiment for an apparatus of the invention, wherein the wrapping process in the packaging material is adapted to take place on a conveyance line in such a way that the mineral wool slab to be packaged is capable of being pushed in a perpendicularly compressed condition by means of and between the first conveyor elements against a packaging material wrapper section present in a substantially straight and preferably substantially vertical or perpendicular position, such that said packaging wrapper, in response to the pushing action, folds over to cover the mineral wool slab over its main surfaces and to extend beyond the mineral wool slab's edges, it is preferred and characteristic that the packaging material wrapper section, present in a substantially straight and preferably substantially perpendicular position, has its immediate vicinity downstream of itself provided on each side of the conveyance line with a pair of suction belt conveyors, which comprises two suction belt circles, one of which is running counter-clockwise and the other clockwise with regard to the advancing direction of the entity, formed by one or more mineral wool slabs, along the line, and which have the unsupported laps of the packaging material, overshooting the entity's edges, pulled by suction to the attachment with themselves from the start of wrapping the packaging material and conveyed between themselves in a controlled manner and in a straight condition to the sealing process.

In this particular preferred embodiment, it is further preferred that those co- directionally running lengths of each suction belt circle in each pair of suction belt conveyors, between which the laps to be sealed proceed in a controlled manner to the sealing process, be spaced from each other by a distance matching the thickness of the entity, formed by one or more mineral wool slabs, to be packaged essentially at the upstream end thereof, approach each other in a directly downstream direction to the immediate nearness of each other, and proceed from here in a downstream direction together co- directionally forward at least over the distance extending alongside the end face sealing bars.

The problems, which are considered having been solved by means of the invention, are primarily the fact that the plastic remains straight all the way to a sealing process for improved sealing reliability, and the fact that the amount of plastic waste is reduced as excessive extra plastics is no longer needed. Drawings

The invention will now be described by way of example with reference to the accompanying drawings, in which:

Fig. Ia shows in perspective a directly lateral view of one packaging apparatus of the invention at such an operating stage in which the wrapping in a packaging material of a mineral wool slab to be packaged has not been started yet,

Hg. Ib shows the same packaging apparatus as fig. Ia, but at such an operating stage in which the wrapping in a packaging material of a mineral wool slab to be packaged has been started and is on-going,

Hg. Ic shows the same packaging apparatus as figs. Ia and Ib, but at such an operating stage in which a mineral wool slab has been wrapped in a packaging material and cross-sealing bars have shifted from an initial position to their sealing position,

Hg. Id shows the same packaging apparatus as figs. Ia-Ic, but at such an operating stage in which both cross-joints for the package of a mineral wool slab have been made and the cross-sealing bars have shifted back to their initial position,

Fig. 2 shows in a view of principle, drawn from a lateral direction, a (second) assembly established by the suction devices and sealing bars of a packaging apparatus, by means of which those laps of packaging material coming to face each other, which overshoot the mineral wool slab's end edges, are sealable to the attachment with each other in a controlled fashion, Fig. 3a shows in a cross-section, taken from the front, the same apparatus as figs. Ia-Ic at such a stage in which a mineral wool slab has been wrapped in a packaging material and end face sealing bars have shifted from an initial position to a sealing position,

Hg. 3b shows in a view of principle the apparatus of fig. 3a as seen directly from above,

Fig. 3c shows in a perspective view a single mineral wool slab to be packaged with its edges and surfaces designated,

Fig. 4 shows in a perspective view how extra packaging material on each side of the apparatus is cut off and removed by suction from two opposite ends of a package (the figure only shows one side of the package), and

Fig. 5 is a perspective view of the apparatus depicted in the preceding figures, as seen from the front thereof counter to the conveying direction.

Examples

This is one example of a packaging method and apparatus of the invention, which enables packaging slabs 1 of e.g. stone wool individually in a plastic wrapper 2. The exemplified packaging apparatus is a so-called horizontal wrapping machine. This type of machines are prior known, but the Applicant has now invented a way of raising the reliability of sealing in machines of this type to a whole new level while reducing the consumption of a packaging material in the form of packaging material waste.

In reference to figs. la-Id, various steps of the packaging method are depicted in principle. The stone wool slabs 1 to be packaged proceed in figs. la-Id between two first conveyor belts 3 and 4, as well as between two second conveyor belts 7 and 8, from left to right in a conveying direction L. The semi-circular arrows within rollers 33, 44, 77, 77', 88 and 88' of the belt conveyors indicate the rotating direction of these rollers. The horizontal wrapping machine is provided with belt conveyors (not shown in the figures) for dispensing from above and from below separate plastic wraps 2' and 2", which for each new stone wool slab 1 to be packaged are joined for an integral plastic wrap 2 by means of a crosswise joint 30 while completing the preceding stone wool slab 1 by finishing its second and, with regard to its advancing direction L, rearward crosswise joint. The outer side of suction devices 10 and 11, used for the controlled sealing of the packaging plastic's 2 unsupported end laps 28 and 29 as well as 28' and 29' (see fig. 3a), according to the invention, is in figs. la-Id located further back in the plane of paper than the outer side of the belt conveyors 3, 4, 7 and 8.

The suction devices, arranged on each side of a conveyance line established by the belt conveyors 3, 4, 7 and 8 of the packaging apparatus, consist on either side of two suction belt conveyors 10 and 11 (as well as 10' and 11', see fig. 3a), which proceed in a direction substantially parallel to the conveyance line's conveying direction L. In this example, the conveyance line and the suction belt conveyors 10 and 11 (as well as 10' and 110 travel, with regard to their longitudinal direction, in a substantially horizontal plane (notice, however, an inclined section in the suction conveyors 10 and 11 as well as 10' and 11^*), but can of course proceed in any plane other than the horizontal plane.

Each pair of suction belt conveyors 10 and 11 as well as 10' and 11' is set up in such a way that, with regard to two suction belt conveyors 10 and 11 or 10' and 11' of a pair, one 11 (or 11', respectively) travels directly above the other 10 (or 10', respectively). In terms of their structural design, the pairs of suction belt conveyors will be described in more detail hereinafter, but the operating principle of the pairs is that the packaging plastic 2 of a package has its unsupported end laps 28 and 29 as well as 28' and 29' (see fig. 3a) closed by suction and conveyed between said pairs in a controlled fashion and in a straight condition to the sealing process.

In the process of packaging a single stone wool slab 1, the wrapping and sealing of the plastic 2 proceeds as follows: The stone wool slab 1 to be packaged is brought between the belt conveyors 3 and 4 as far as to the pair of cross-sealing bars 5 and 6, whereof the bar 5 lies directly above the lower bar 6 and is adapted in the process of sealing to move downward to a contact with the lower bar 6. The lower bar 6 may be adapted to move in the process of sealing to some extent upward towards the upper bar 5. The structural design and operating principle of the bars 5 and 6 in a pair of cross-sealing bars are prior known technology.

When the wool slab 1 to be packaged has advanced as far as to a vertical plane of the cross-sealing bars 5 and 6 (other than a vertical plane if the plane established by a conveyance line is inclined relative to a horizontal plane), it is compressed down between the first conveyor belts 3 and 4. Hg.

Ia depicts this compressing step in a packaging process, wherein the stone wool slab 1 to be packaged has its long flank 23 (see also fig. 3c), lying "foremost" as regards its advancing direction, brought to an engagement with the packaging plastic 2, but wrapping it in the plastic 2 is yet to be started.

Hg. Ib shows a packaging step, in which a wrapping process of the to-be- packaged stone wool slab 1 in the plastic 2 has been started and is on-going. Also depicted in this figure is how the two end laps of one end face of the package are guided between and by means of the top and bottom suction belt conveyors 11 as well as 10, respectively (and on the other side between the top 11' and bottom 10' suction belt conveyors, respectively). The packaging plastic 2 has its upper end lap 28 (on the other side 28', respectively, see fig. 3a) pulled by suction to the engagement with a bottom length of the upper suction belt circle 11 (on the other side 11', respectively) and the plastic's lower end lap 29 (on the other side 29J, respectively) is likewise pulled by suction to the engagement with a top length of the lower suction belt circle 10 (on the other side 10', respectively). Thus, the packaging plastic retains its straight condition from the start of a wrapping process all the way until all four joints of the stone wool slab 1, i.e. two crosswise joints 30 and 32 and two end face joints (not shown in the figures), are completed.

Fig. Ic shows a packaging step, in which the stone wool slab 1 has been wrapped in the plastic 2 and the upper cross-sealing bar 5 has shifted from its initial position, i.e. from a position substantially coplanar with the upper conveyor belts 3 and 7, to a sealing position in the engagement with the lower cross-sealing bar 6, which has moved upward to some extent. At this point, on the other side of a product package, i.e. on the side of its long flank 24 (see fig. 3c), lying "rearmost" with respect to the line advancing direction L, is made a double joint crosswise to the packaging line's direction L, and between these two crosswise joints the plastic 2 is severed by cutting, at the same time forming also a "first" or "foremost" crosswise joint for the next package.

Fig. Id finally shows a packaging step, in which both crosswise joints 30 and 32 are completed for a package of the stone wool slab 1 and the upper cross-sealing bar 5 has shifted back up to its initial position and the lower cross-sealing bar 6 respectively down to its initial position.

The cross-sealing and the cutting between the seals of a double joint represent prior known technology for a skilled artisan. Therefore, the figures illustrate neither a double resistance wire nor a cutter disposed between these wires.

Hence, the stone wool slab 1 to be packaged is pushed in a compressed condition between two wide belt conveyors 3 and 4 as far as to the cross- sealing bars 5 and 6. The other two wide belt conveyors 7 and 8, disposed downstream of the sealing bars, hold the package in compression until the second, i.e. rearmost in the line direction L, lateral side or flank 24 of the package has been sealed up. After this, the package proceeds forward for the sealing of its end faces 20 and 21.

Thus, the stone wool slab 1 to be packaged is pushed by means of and between the first belt conveyors 3 and 4 in a condition compressed in its perpendicular direction against a plastic wrap section 2 present in a substantially perpendicular position (preferably in a substantially vertical position, if the conveyance line is horizontal). In response to this push- inflicted displacement of the stone wool slab 1, said packaging wrap 2 folds over in a space between the two second belt conveyors 7 and 8 to cover the stone wool slab 1, advancing into the space between these two second belt conveyors, over its two main surfaces 22 and 22' and to extend beyond edges 20', 21', 23', 24' and, respectively, edges 20", 21", 23", 24" of the main surfaces' 22 and 22', covering thereby the end faces 20 and 21 as well as the sides 23 and 24 (see fig. 3c).

As shown in fig. 3a, the plastic wrap 2 is dimensioned in terms of its width so as to extend beyond the end edges 20' and 20" as well as 21' and 21" sufficiently for enabling the packaging plastic's unsupported end laps 28 and 29 as well as 28' and 29', respectively, overshooting the stone wool slab's 1 end faces 20 and 21 and coming face-to-face with each other, to be sealed to the attachment with each other by means of the suction belt conveyors 10 and 11 and the suction belt conveyors 10' and 11', respectively, essentially from the start of wrapping all the way until completing the sealing process controlled by means of the suction belt conveyors 10 and 11 and the suction belt conveyors 10' and 11', respectively.

The suction belt conveyors 10 and 11 (or 10' and 110 of each pair of suction belt conveyors are disposed in the immediate vicinity of the perpendicularly existing plastic wrap section 2 on the downstream side immediately after the pair of cross-sealing bars 5 and 6. As shown in fig. 2, in each suction device or pair of suction belt conveyors 10 and 11 (or 10' and 110, the top suction belt circle 11 (and 110 funs in a counter-clockwise rotation, as indicated by an arrow v, and the bottom suction belt circle 10 (and IOO in a clockwise rotation, as indicated by an arrow m, in a vertical plane which is co- directional with the advancing direction L of the stone wool slab 1. The unsupported laps or end laps 28 and 29 as well as the respective end laps 28' and 29' of the plastic wrap 2, which are overshooting the end edges 20' and 20" as well as 21' and 21" of the stone wool slab 1, are drawn by vacuum to an engagement with both belt circles 10 and 11 (or 10' and 11', respectively) of each pair of suction belt conveyors from the start of wrapping the plastic 2, hence proceeding therebetween in a controlled manner and in a straight condition to the sealing process.

Depicted in fig. 2 is how those opposing lengths of two overlapping suction belt circles 10 and 11 or 10' and 11' included in each pair of suction belt conveyors, between which the end laps 28 and 29, as well as respectively the end laps 28' and 29' to be sealed, proceed in a controlled manner to a sealing process, are at their upstream end spaced from each other by a distance d matching substantially a thickness of the compressed (or non- compressed) stone wool slab 1 to be packaged. From this upstream end thereof, both of said lengths approach each other over inclined sections 100 and 101 in a downstream direction, i.e. in the direction L, in a substantially straight condition to a substantially immediate nearness, and proceed from here in a downstream direction together essentially in a parallel relationship with the conveyance line's direction L forward with end sealing bars 12 and 13 as well as 12' and 13', alongside the end sealing bars, at least over a distance matching the length of said end sealing bars. The inclined sections 100 and 101 are supported by backing plates 40 and 41 disposed in a matching inclination or by corresponding elements. In other words, the face- to-face end laps 28 and 29, as well as the respective end laps 28' and 29' to be sealed to each other, proceed, while having been pulled by suction to the engagement with the top and bottom suction belt conveyors 11 and 10 as well as respectively with the suction belt conveyors 11' and 10', substantially between the top conveyor belt 7 and the bottom conveyor belt 8 from the respective levels towards the midpoint in a space between the top and bottom conveyor belts 7 and 8, at which point said laps confluence between the suction conveyor belts 11 and 10 as well as 11' and 10' to become co- directional.

With the plastic 2 in compression between the suction belts 10 and 11, the sealing of plastic takes place (see e.g. fig. 3a). At this point, a double joint can be made. Both end sealing resistances can be normal flat wire resistances coupled with the end sealing bars 12 and 13 (as well as 12' and 130- Optionally, the end sealing can also be conducted by means of heat guns, ultrasound or laser, most preferably, however, with the above- mentioned end sealing bars 12 and 13 (as well as 12' and 130 as these are financially more attractive than other options and make a reliable joint.

The resistance wires 14 and 14', disposed downstream of the end sealing bars 12 and 13 as well as 12' and 13' on either side of the conveyors 7 and 8, cut off excessive packaging plastic 2. Shown in fig. 4 is one 14' of the resistance wires disposed on either side of the belt conveyors 7 and 8 carrying the stone wool slabs 1. As apparent from fig. 4, the resistance wire 14' is located between a downstream end of the end sealing bars 12' and 13' and a downstream end of the suction belts 10' and 11'. This implies, therefore, that the suction belt conveyors 10 and 11 as well as 10' and 11' extend co-directionally with the line at least slightly further than the end sealing bars 12 and 13 as well as 12' and 13'. After the sealing process, the resistance wire is used for cutting off extra packaging plastic 2 by driving the packaged product against the resistance wire 14' (and 14). The resistance wires 14 and 14' can also be replaced by a laser cutter or the like cutting device. Because the end laps of the plastic wrap 2 are held on, it is possible to use a narrower strip of plastic. Thereby, the amount of plastic waste is reduced. In the past, the plastic arrived in a "crumpled" condition at the end sealing process, which is why some extra plastic was needed to be on the safe side. In addition, if the plastic laps had been excessively narrow, there would have been no way in the prior art to introduce the same between the sealing bars 12 and 13 as well as 12' and 13'.

The cut-off packaging plastic 2 is suction-drawn by means of a suction pipe system 27, shown in figs. 4 and 5, into a receptacle 17 shown in fig. 5. The receptacle can be a bin 17 or it may include a plastic sack for vacuuming extra packaging plastic therein. The plastic sack, along with its contents, is easy to place in a baler, thus facilitating remarkably the removal of plastic waste as compared with the currently available packaging apparatus, in which the "plastic removal grippers" drop the waste plastic into cardboard boxes disposed on either side of the machine. Thus, the packaging apparatus becomes structurally simpler by enabling the omission of "plastic removal grippers", which are in fact "jaws" that are operated by compression cylinders and grab hold of the plastic. Because the entire jaw element is pulled aside by a pneumatic cylinder and the jaws are opened and the plastic falls down into a cardboard box, this implies a lot of action and thereby a lot of error possibilities.

By virtue of a horizontal packaging machine described in this example, the plastic hence remains straight in a sealing process, whereby the reliability of sealing improves, the amount of plastic waste is reduced, and the removal of resulting plastic waste is facilitated.

Furthermore, the replacement of end sealing resistances is facilitated and at the same time becomes safer in the new packaging machine, because, in the past, the resistance wires had to be removed from and installed on a fixed bar, whereby someone had to go "inside the machine" to conduct the replacement work. Now, the bar can be lifted away and the resistance wire replaced outside the machine. All that is needed is to screw off the electric wires. The machine improves also in terms of its adjustability, i.e. it enables running shorter packages and at the same time reducing the height of a package. In the past, the frame impeded the movements of side sealers or, in other words, the end sealers 12 and 13. The compression of a package can also be increased as the end sealing bars 12 and 13 are brought closer to each other. As a result of the replacement of end sealing resistances becoming easier, the down times of a packaging machine will be shorter as the resistance wire need not be replaced inside the machine any more. The time consuming wire replacement and tape applications can now be conducted by using substitute bars while the machine is running. Replacing the resistances for a disengaged bar is easier than for a bar permanently fixed to the machine

The prior art end sealing bars cannot be moved sufficiently close to each other, because the structural design of the apparatus does not afford room for bringing them any closer to each other. At present, the displacement is impeded by the cylinders of a press element, which come to contact with the upper belt if the end sealing bars are shifted too close to the package. The same thing prevents the making of flatter packages.

Claims

1. A method for packaging slab-like mineral wool products in a non- compressed or compressed condition in a packaging material (2), in which method an entity (1) to be packaged, formed by one or more mineral wool slabs, advances along a conveyance line consisting of conveyor elements (3, 4, 7, 8) for wrapping the same in the packaging material, such that, as a result of wrapping, the packaging material (2) is caused to cover the entity (1) of one or more mineral wool slabs over its main surfaces (22, 220 and to extend beyond the edges (20', 21', 23', 24'; 20", 21", 23", 24") sufficiently for enabling the unsupported laps of packaging material, overshooting the edges of the entity formed by one or more mineral wool slabs and coming face-to-face with each other, to be sealed to the attachment with each other, characterized in that those laps (28, 29; 28', 290 of the packaging material (2) coming face-to-face with each other, which overshoot those edges (20', 21'; 20", 21") of the entity (1) formed by one or more mineral wool slabs, which are substantially parallel to an advancing direction (L) of this particular entity (1) of one or more mineral wool slabs, are held on by means of suction at least during the course of sealing the aforesaid laps of packaging material, whereby the packaging material remains (2) substantially straight in the sealing process.

2. A method as set forth in claim 1, characterized in that the sealing processes are conducted while compressing the entity of one or more mineral wool slabs in its perpendicular direction.

3. A method as set forth in claim 1 or 2, characterized in that, after the suction-controlled sealing process, extra packaging material (2) is cut off of those two opposite end faces (25, 26) of the entity, which are substantially parallel to the advancing direction (L) of this particular entity formed by one or more mineral wool slabs, by driving the packaged product on the conveyance line against a resistance wire (14, 140, a laser cutter or the like cutting element, located on each side of the product and the conveyance line conveying the same.

4. A method as set forth in claim 3, characterized in that the extra cut-off packaging material is removed by suction from both sides into a sack, a bin

(17) or the like receptacle.

5. A method as set forth in any of claims 1-4, characterized in that the packaging material consists of plastics or other meltable material, which is sealed by fusing the laps facing each other to the attachment with each other.

6. A method as set forth in any of claims 1-5, characterized in that on the product's end faces (20, 21) is made a double-sealing joint.

7. A method as set forth in any of claims 1-6, wherein the entity (1), formed by one or more mineral wool slabs, has its wrapping in the packaging material (2) conducted on a conveyance line in such a way that the entity (1) to be packaged is pushed in a perpendicularly compressed condition by means of and between the first conveyor elements (3, 4) against a packaging material wrap section (2) present in a substantially straight and preferably perpendicular position, whereby said packaging wrap, in response to a push-induced displacement of the entity, folds over to cover the entity over its main surfaces (22) and to extend beyond the entity's edges (20', 21', 23', 24'; 20", 21", 23", 24"), characterized in that the control by suction is performed essentially from starting the wrapping at least until finishing the sealing of those laps (28, 29; 28', 290 which are held on by suction.

8. A method as set forth in any of claims 1-7, wherein the entity to be packaged only consists of one mineral wool slab (1).

9. An apparatus for packaging slab-like mineral wool products in a non- compressed or compressed condition in a packaging material (2), said apparatus comprising a conveyance line consisting of conveyor elements (3, 4, 7, 8), along which each entity (1) to be packaged, formed by one or more mineral wool slabs, advances for wrapping the same in the packaging material, such that, as a result of wrapping, the packaging material is caused to cover the entity (1) over its main surfaces (22, 220 and to extend beyond the entity's (1) edges (20', 21', 23', 24'; 20", 21", 23", 24") sufficiently for making the unsupported laps of packaging material overshooting the entity's edges and coming face-to-face with each other capable of being sealed to the attachment with each other by means of sealing devices (5, 6; 12, 13) included in the apparatus, characterized in that the apparatus is equipped with suction devices (10, 11), by means of which those laps (28, 29; 28', 290 of packaging material coming face-to-face with each other, which overshoot those edges (20', 21'; 20", 21") of the entity (1) formed by one or more mineral wool slabs, which are substantially parallel to an advancing direction (L) of this particular entity (1), are held on by the suction devices (10 and 11) at least during the course of sealing the aforesaid laps of packaging material, whereby the packaging material (2) remains substantially straight in the sealing process.

10. An apparatus as set forth in claim 9, characterized in that the suction devices (10 and 11; 10' and 110 for controlled sealing are provided on each side of a conveyance line, conveying the entity (1) to be packaged, downstream of those sealing devices (12, 13; 12', 130 which are used for sealing up those unsupported laps of packaging material which, in the longitudinal direction thereof, are perpendicular to said advancing direction (L).

11. An apparatus as set forth in claim 9 or 10, characterized in that the suction devices comprise two suction belt conveyors (10, 11; 10', 110, which have the unsupported laps (28, 29; 28', 290 of the packaging material (2), overshooting the end edges (20', 21'; 20", 21") of the entity (1) formed by one or more mineral wool slabs, pulled by suction to the attachment with and conveyed between the same in a controlled manner and in a straight condition to the sealing process.

12. An apparatus as set forth in any of claims 9-11, characterized in that the controlled sealing is adapted to be conducted by at least those sealing devices (12, 13; 12', 130, lying on each side of the conveyance line's conveyor elements between each end face (20, 21) of the product (1) and the suction devices (10, 11; 10', 110 associated therewith.

13. An apparatus as set forth in any of claims 9-12, characterized in that, on each side of the conveyance line conveying the mineral wool slabs (1), downstream of those sealing devices (12, 13; 12', 130 used for sealing those laps (28, 29; 28', 290 which are substantially parallel to the package advancing direction (L), the apparatus is provided with a resistance wire (14, 140, a laser cutter or the like cutting device for cutting extra packaging material (2) off of these two end faces (20, 21) of the package.

14. An apparatus as set forth in any of claims 9-13, characterized in that the conveyance line's conveyor elements comprise one or more pairs made up by belt conveyors (3, 4; 7, 8), between which the sealing processes are conducted while compressing the entity (1) to be packaged, formed by one or more mineral wool slabs, in a direction perpendicular thereto.

15. An apparatus as set forth in claim 13 or 14, characterized in that the extra cut-off packaging material (2) is removed by suction through a suction pipe system (27), provided on each side, into a sack, a bin (17) or the like receptacle.

16. An apparatus as set forth in any of claims 9-15, characterized in that the sealing devices (5, 6; 12, 13) comprise one or more resistance wires (14, 140, in response to whose melting effect on the packaging material (2) made of plastics, the laps facing each other are respectively sealable to the attachment with each other by one or more joints.

17. An apparatus as set forth in any of claims 9-16, wherein the wrapping process in the packaging material (2) is adapted to take place on a conveyance line in such a way that the entity (1) to be packaged, formed by one or more mineral wool slabs, is capable of being pushed in a perpendicularly compressed condition by means of and between the first conveyor elements (3, 4) against a packaging material wrap section (2) present in a substantially straight and preferably substantially perpendicular position, such that said packaging wrap, in response to the pushing action, folds over to cover the entity (1) over its main surfaces (22, 220 arid to extend beyond its edges (20', 21', 23', 24'; 20", 21", 23", 24'0, characterized in that the packaging material wrap section (2), present in a substantially straight and preferably perpendicular position, has its immediate vicinity downstream of itself provided on each side of the conveyance line with a pair of suction belt conveyors, which comprises two suction belt circles (10, 11; 10', 110, one (11, 110 of which is running counter-clockwise and the other (10, 100 clockwise with regard to the advancing direction (L) of the entity (1), formed by one or more mineral wool slabs, along the line, and which have the unsupported laps (28, 29; 28', 290 of the packaging material (2), overshooting the entity's edges (20', 21', 23', 24'; 20", 21", 23", 24'0, pulled by suction to the attachment with themselves from the start of wrapping the packaging material (2) and conveyed between themselves in a controlled manner and in a straight condition to the sealing process.

18. An apparatus as set forth in claim 17, characterized in that those co- directionally running lengths of each suction belt circle (10, 11; 10', 110 in each pair of suction belt conveyors, between which the laps (28, 29; 28', 290 to be sealed proceed in a controlled manner to the sealing process, are spaced from each other by a distance (d) matching the thickness of the entity (1), formed by one or more mineral wool slabs, to be packaged essentially at the upstream end thereof, approach each other in a directly downstream direction to the immediate nearness of each other, and proceed from here in a downstream direction together co-directionally forward at least over the distance extending alongside the end face sealing bars (12, 13).