MXPA00003640A - Process for forming of strip like sheets - Google Patents

Abstract

Foil strip (2) is continuously accordion pleated (110) so that the ridges (21,22) are at a constant angle, e.g. 20 to 70 deg , to the edge of the strip. The pleated strip (2') is then plastically deformed between roller pairs (120) to give the ridges (21,22) in the edge region (30b) a curved shape (31,32) with a continuously increasing angle of 80 to 90 degrees at the edge. The strip (2) can have a surface structure, e.g. grooves or expanded metal, or can be perforated or consist of wire mesh. T forming rollers (120) have teeth of the required curvature and can be built up of a stack of laminations. Alternatively, oscilla form tools can be used.

Description

METHOD FOR FORMING FILMS IN THE FORM OF A BAND The invention relates to a method for forming films in the form of a band and a plant for carrying out the method. A material exchange column with a structured packing is known from WO 97/16247 (= P.6765) which is developed from packaging elements that are arranged one above the other and which in each case has a transverse channel structure , with the channels in an upper and lower edge region of a packaging element of this kind which is formed with a special configuration. As a result of the special conformation of the packing elements, a reduced flow resistance results for a gas flowing through the packing and in which it passes from a packing element to an adjacent element. The object of the invention is to create a method by which the films can be suitably shaped so that the named packages can be manufactured with the named films. This object is satisfied by the method which is characterized in claim 1. In this the term "strip-shaped film" shall be understood to mean any band of material that can be configured in accordance with the invention. A strip of material of this kind can for example also consist of a wire mesh or an expanded metal. The method for shaping films (2) in the form of a band, in particular for structured packaging, comprises the following stages. a) Continuously feeding a film web from a film feeder to the forming units, b) Folding the film web into a first forming unit. In this unit the edges that form an angle of inclination are produced with the edges of the film band having a constant value. c) After advancing the folded soft in at least one additional forming unit, the latter is reconfigured in one or more stages. In this unit the edges are eliminated through plastic deformation by means of a pair of rolls in the edge areas outwards of an intermediate zone of the band and are at the same time replaced by curved edges. The angles of inclination of the curved edges increase continuously from the intermediate zone towards the edge of the band.

The subordinate claims 2 to 7 relate to advantageous embodiments of the method according to the invention. The subject of claims 8 to 10 is a plant for carrying out the method. The invention will be described in the following with reference to the drawings. Shown are: Figure 1 a plant for carrying out the method according to the invention, Figure 2 an edge zone which has been reformed according to the method of the invention, Figure 3 is cross-sectional profile of a pair of rollers, Figure 4 the lower roller of the roller pair of Figure 3 with two reconfigured parts • axially arranged, Figure 5 a reshaped edge area of a film, the reshaping of the which has been executed in three stages of reconfiguration, Figure 6 a side view of the film of Figure 5 with an illustration of the change of geometry in the three stages of reconformation and Figure 7 a fragment of a film having a groove so as well as a perforation.

The plant illustrated in Figure 1 comprises the following components: a device 10 for continuously advancing a film web 2 from a film supply not illustrated to the shaping units 11, 12, 12 ', 12"; a first shaping unit 11 for folding the film web 2, with a band of film 2 'formed in zigzag or corrugated that is formed, three shaping units 12, 12', 12", to reshape the film web 2 ' by means of a pair of rollers 120 in each case; the apparatus 13 to extract the bands of film 2 'and 3 formed. The folding can be carried out with a pair of rollers in the form of a toothed wheel or through pressure with an oscillation tool 110. The details of the folding procedure (or "inclined folding") can be found in EP-A 0 739 846 (= P.6670). Figure 2 shows a part of a folded film strip 3 which has resulted from a film strip 2 'through the reshaping of an edge area 30b of amplitude R. A second edge region, which is similarly reshaped, does not appear in the drawing. Only an intermediate zone 30a or a part of this zone is illustrated. The original folding of the film webs 2 'occurs in the intermediate zone 30a with parallel edges 21, 22 straight. In the edge area 30b the original folding is indicated in dotted chain line. An outer cutting edge 35 of the edge region 30b extends parallel to an unillustrated edge of the film web 2 '. The edges 21, 22 subtend an inclination angle fa a straight line 33 extending parallel to the cutting edge 35. The edges 31, 32 of the edge region 30b lying on a curved path form variable angles of inclination which are formed by the tangents in the named curves and the straight line 33. These variable inclination angles are continuously increased from the intermediate zone 30a to the edge of the band (or cutting edge 35). The film band 3 has a height h; this produces the width of the layer of a package with a transverse channel structure that is produced from pieces of film web 3 and through a covered construction. For the explanation of the reshaping of the edge region 30b in FIG. 2, it is subdivided into a plurality of bands correspondingly subdividing a disk-like volume of weight h and amplitude R in bar-shaped partial volumes 41, 42 .... It is illustrated for an edge 21 or 31 respectively by arrows 5a and 5b which are associated with the partial volumes 41, 42, ... As the elements of the film 2 'that fall horizontally are vertically displaced during the reshaping. The length of the arrows 5a and 5b show qualitatively how long the displacements of the surface elements are; These lengths are roughly proportional to travel trajectories during travel. Through a plastic deformation carried out by means of a pair of rollers, the edges 21 of the original folding are eliminated (arrows 5a) and replaced by curved edges 31 (arrows 5b). The elimination of the edges 21 and the new formation of the edges 31 that takes place adjacently occurring practically simultaneously. Figure 3 shows a cross section through two upper rollers 121 of the roller pair 120. The serrated profile of the lower rollers 22 are illustrated in the dotted chain line. Between the two rollers 121 and 122 there is a settable space 123 which is established according to the thickness of the film 2 '. The directions of rotation are illustrated by the arrows 61 and 62. The rollers 121, 122 can be manufactured from a large number of lamellas by means of which the roller profile can be formed in a simple manner instead of a piece solid All the lamellae have in each case the same gear profile. The adjacent lamellae are arranged adjacently with a displacement by angles, with the angles that are determined by the required shaping of the profiled rolls and the thickness of the lamellae. The rollers 121 and 122 respectively and advantageously comprise two axially reconfigured parts 122a and 122b disposed on a drive shaft 124: see, FIG. 4 in which the lower roller 122 of FIG. 3 is illustrated. Each reshaped portions 122a and 122b receive a reshaped profile 130b to reshape the edge zones 30b (amplitude R) and a profile 130a which fits * without reconfiguring to the profile given by the folding of the film web to be processed. Between the reconfigured portions 122a and 122b which are secured to a cylindrical carrier body 124 ', there is a slotted ring with an amplitude b of a settable slot. The reconfiguration is carried out at an established slot width b for which the reformed film strip 3 is maintained within the shaped profile R despite a transverse expansion of the edge regions. It is transverse expansion, which can reach approximately 1 to 3 mm, arising as a result of plastic deformation. The slot width b is preferably set such that when it emerges from the roller pair * 120 of the film edges 36 (see Figure 5) they come to rest on the outer edges 135 of the reshaping profile 130b so that the The width B of the roller is thus only as large as the width of the film strip 3 after the reconfiguration. To establish the width B, the carrier body 124 'and the connection means between these carrier bodies 124' and the reshaping parts 121, 122 are suitably constructed. The width B is expediently increased in that the two reshaped portions 121, 122 move in opposite directions along the arrows 6a and 6b shown in Figure 4. At the outlet of the roller pair 120, the film strip 3 must be guided at the edges in such a way that a movement of the strip 3 transversely to the direction to be advanced is avoided. Figure 5 shows the edge region of a film strip 3, which is manufactured by means of three stages of reshaping from a 2 'band of folded film (edge 21 and 22 in the line in chain points) so soon as the edge 31 which is formed during the reshaping and which rests upwards intersects an adjacent end 21 of the original film band 2 'which likewise rests upwards, at point 7, then at least a second stage of reshaping is necessary. For each stage of reshaping, however, only two directly adjacent edges 21 (which lie upwards) and 22 (which lie downwards) can be reconformed at the same time. Since in the illustrated example the edges 31 cross two edges 21 that lie adjacently upwards, that is to say at points 7 and 8, a three-stage reconformation step is required. In the reshaping stages, a zigzag profile of the band end 36 moves successively to the right; see Figure 6. In the uppermost partial figure, the edge 36 'of the film band 2' still not reformed is shown. The partial figure shows the profile of the zigzag displaced after the first stage of reshaping. The horizontal arrow 81 indicates how the edge 21 looks as new as the edge 31 '. The vertical arrows 5 indicate how the surface elements are displaced upwards or downwards as a result of the reshaping. The arrows 82 and 83 represent the additional displacements of the edges 31 'and 31"respectively in the second and third reshaping stage, with the edge 31" emerging towards the edge 31 in Figure 5 in the third, step. In the last step of reshaping, the edge region 30b is designed in such a way that the angle of inclination of the film edges 36 is greater than 80 ° and in such a way that it preferably rises to 90 °. In folding a value in the range from 20 ° to 70 ° can be chosen by the angles of inclination f of the 2 'band of film. The films can be used which have a refined structure for example, the form of flutes and / or a perforation for example of through holes which are arranged in a grid-like manner. Figure 7 shows a corrugated film with the groove 37 that is formed by transverse grooves. This film is also perforated by holes 38 which are arranged in a grid-like manner. The reshaping which is carried out in the method according to the invention leaves a refined structure given largely intact.

Claims (8)

1. CLAIMS 1. A method for forming films in the form of a strip comprising the following steps: a) continuously feeding a film web from a film feeder to the forming units: b) folding the film web into a first forming unit. In this unit the edges forming an inclination angle are produced with the edges of the film web having a constant value, and c) - after advancing the folded web in at least one additional forming unit, the former is reconfigured in the band in one or more stages. In this unit, the edges are eliminated through plastic deformation by means of a roll of rollers in the edge areas towards the outside of an intermediate zone of the strip and at the same time replaced by curved edges. The angles of inclination of the curved edges increase continuously from the intermediate zone towards the edge of the band.
2. 2. Method according to claim 1, characterized in that a value in the range of 20 ° to 70 ° is chosen for the angle of inclination of the fold; and in which the bands of shaping and reshaping material can be used as films having a refined structuring for example in the form of a stria and / or a uniform perforation for example, through through holes which are arranged in the form of a grid.
3. 3. Process according to the rei indication 1 or claim 2, characterized in that each of the rollers to the pair of rollers comprises two parts of reconfiguration axially arranged which in each case contain a profile of reshaping to reshape the edge area and between which is a slotted ring with a settable slot width that remains open; and wherein the recoding is carried out in a slot width established for which the reshaped film web is maintained within the reshaping profile despite transverse expansions of the edge regions and is preferably maintained in such a way that Film edges come to lie at the outer end of the reshaping profile when it emerges from a pair of rollers.
4. Process according to any of claims 1 to 3, characterized in that for each stage of reshaping in each case only two directly adjacent edges of the film strip are reshaped simultaneously.
5. 5. Method according to any of claims 1 to 4, characterized in that in its emergence from the pair of rollers, the film strip is guided at the edges in such a way that a movement in the band transversely to advance the direction is prevent.
6. 6. Method according to any of claims 1 to 5, characterized in that the folding is carried out with a pair of rollers in the form of a gear wheel or through reconformation with an oscillating tool.
7. 7. Method according to any of claims 1 to 6 characterized in that in the last stage of reshaping the edge area is formed such that at the film edges of the angle of inclination is greater than 80 ° and that preferably amounts to 90 .
8. 8. Plant for carrying out the method according to any of claims 1 to 7, comprising the following components: a device for. continuously advancing a film web from a supply of film to the forming units, a first forming unit for folding the film web, - at least a second forming unit for reforming the folded film web by means of a pair of rollers having no reconfiguration perfilations in an intermediate zone and deformation perfilations in extreme zones, and - at least one apparatus for extracting the formed film web. Plant according to claim 8, characterized in that the rollers have adjustable amplitudes for reshaping, in particular they have amplitudes that are adjustable according to claim 3; and in that for each pair of rollers or space it can likewise be established between the rollers. Plant according to claim 9, characterized in that the rolls are made from a solid piece or from a large number of lamellae, with each lamella having in each case a same gear profile, the lamella being disposed adjacent to the lamellae. a displacement by angles and with the values to be chosen by these angles to be, being determined by the required shape of the roll profile and the thickness of the lamella.