AU742361B2

AU742361B2 - Installation for producing 5-layered corrugated board

Info

Publication number: AU742361B2
Application number: AU46109/99A
Authority: AU
Inventors: Edmund Bradatsch; Paul Engel
Original assignee: Visy R&D Pty Ltd
Current assignee: Visy R&D Pty Ltd
Priority date: 1998-06-25
Filing date: 1999-06-16
Publication date: 2002-01-03
Anticipated expiration: 2019-06-16
Also published as: NZ502667A; EP1007347A1; DE19828124A1; AU4610999A; JP2002518227A; WO1999067083A1

Description

METHOD AND APPARATUS FOR THE MANUFACTURE OF AT LEAST 4-LAYER CORRUGATED BOARD The invention relates to a method for the manufacture of at least 4-layer corrugated board, comprising an upper smooth first liner; a smooth intermediate layer; an upper first corrugated layer, which is disposed between, and glued to, the upper first liner and the intermediate layer; and a lower second corrugated layer, which is disposed below, and glued to, the intermediate layer; and an apparatus for putting the method into practice.

An apparatus for the manufacture of 5-layer corrugatedboard is known from WO 91/17881, in which two single-faced webs of corrugated board are supplied to a heating device. The webs of corrugated board are supplied in such a way that the corrugated layers face each other and the liners of the two single-faced webs of corrugated board constitute the respective liners of the 5-layer corrugated board.

Before entering the heating device, the two webs of corrugated board are led past fluted rolls which are driven synchronously so that the two webs of corrugated board arrive in the heating device for the crests of the two corrugations that are turned away from the respective liner to be in congruence with each other i.e., ••oo mirror-symmetrical. For producing a 5-layer web of corrugated board, an intermediate layer is fed in. Glue is spread on the crests of the corrugated layers by means of two glue spreading units. This apparatus has the drawback of the feeders for the supply of the two webs of corrugated board being designed for mirror symmetry, which means that the webs of corrugated board cannot be supplied from two identical machines for the manufacture of single-faced corrugated board.

Rather, a special machine is needed.

DE 42 36 211 Al teaches, in a heating device, to bring together two singlefaced webs of corrugated board and a liner and to join them to form a 5-layer web of corrugated board. The two webs of corrugated board are supplied in an identical position the liner is on the top and the corrugated layer is at the bottom. The additional liner is supplied from below. This design allows the single-faced webs of Melboume\003916782 Printed 8 October 2001 (17:06) corrugated board to be supplied directly from the manufacturing machines. A drawback resides in that the webs of corrugated board cannot be brought together in such a way that the crests of one web of corrugated board are congruent with the troughs of the other web of corrugated board.

WO 97/00769, WO 93/03913, WO 96/32250, U.S. 5,674,349 and EP 0 279 609 B1 teach to manufacture 4-layer webs of corrugated board by two corrugated layers being united by means of fluted rolls in such a way that the crests of the corrugated layers are joined to each other. One or two exterior liners are applied simultaneously or subsequently. The supply of an intermediate layer is not known from this.

A fundamental problem with all these known designs resides in that in the case of two or several webs of corrugated board that are to be united, the spacing is ••go never identical even if the machines for the manufacture of a single-face lined web of corrugated board are to produce an identical spacing.

It is an object of the invention to embody a method and an apparatus for the manufacture of at least 4-layer corrugated board, ensuring that the crests of one web of corrugated board are in congruence with the troughs of the other web of corrugated board.

oooo According to the invention, there is provided a method for the manufacture oo 20 :of at least 4-layer corrugated board which comprises an upper smooth first liner, a smooth intermediate layer, an upper first corrugated layer disposed between the upper first liner and the intermediate layer and glued thereto, and a lower second corrugated layer disposed below the intermediate layer and glued thereto; a) conveying a single-faced first web of corrugated board in a direction of production, including the smooth first liner and the first corrugated layer with a first corrugation and crests and a first spacing; b) conveying a single-faced second web of corrugated board in the direction of production, including the smooth intermediate layer as a second liner and the second corrugated layer with a second corrugation and crests and troughs and a second spacing, the first corrugated layer being turned toward the second liner Melbourne\003916782 Printed 8 October 2001 (17:06) and the second spacing of the second corrugated layer being slightly smaller than the first spacing of the first corrugated layer; c) measuring the first spacing of the first corrugated layer; d) measuring the second spacing of the second corrugated layer; e) said second web of corrugated board being elongated in the direction of production in dependence on the measured first spacing and the measured second spacing such that the second spacing becomes equal to the first spacing; f) detecting the position, in the direction of production, of the first corrugation of the first corrugated layer relative to the position of the second corrugation of the second corrugated layer; g) the first web of corrugated board and the second web of corrugated board being displaced relative to each other in the direction of production such that the crests of the first web of corrugated board are synchronized with the troughs of the second web of corrugated board; h) applying glue to the crests of the first corrugated layer; and i) bringing the first web of corrugated board and the second web of corrugated board with applied pressure to join the webs to each other.

o The invention further provides an apparatus for putting into practice the method according to one of claims 1 to 6, including: S 20 a) a device for the supply, in a direction of production, of a single-faced "first web of corrugated board, which comprises the smooth first liner and the first oooo corrugated layer with a first corrugation and crests and a first spacing; b) a device for the supply, in the direction of production, of a singlefaced second web of corrugated board, which comprises the smooth intermediate layer as a second liner and the second corrugated layer with a second corrugation and crests and troughs and a second spacing, with the first corrugated layer being turned toward the second liner and the second spacing of the second corrugated layer being slightly smaller than the first spacing of the first corrugated layer; c) a device for the detection of the first spacing of the first corrugated layer; Melbourne\003916782 Printed 8 October 2001 (17:06) d) a device for the detection of the second spacing of the second corrugated layer; e) a device for the elongation of the second web of corrugated board in dependence on the detected first spacing and the detected second spacing in the direction of production such that the second spacing becomes equal to the first spacing; f) a device for the detection of the position of the first corrugation of the first corrugated layer relative to the position of the second corrugation of the second corrugated layer in the direction of production; g) a device for the displacement of the first web of corrugated board and the second web of corrugated board relative to each other in the direction of 0 OV* production such that the crests of the first web of corrugated board are in 9.9.

congruence with the troughs of the second web of corrugated board; Sh) a gluing device for glue to be spread on the crests of the first 15 corrugated layer; and i) a device for bringing together, pressing on, and joining to, each other the first web of corrugated board and the second web of corrugated board.

Advantageous embodiments of the invention will become apparent from the o sub-claims.

e 20 Further features, advantages and details of the invention will become apparent from the ensuing description of two exemplary embodiments, taken in conjunction with the drawing, in which Fig. 1 is a diagrammatic lateral view of an apparatus for the manufacture of corrugated board; Fig. 2 is a lateral view of a 5-layer corrugated board; Fig. 3 is a lateral view of a device for the detection of the spacing of a singlefaced web of corrugated board; Fig. 4 is an illustration of two single-faced webs of corrugated board of varying spacing; and Fig. 5 is a lateral view of another embodiment of a device for the detection of Melboume\003916782 Printed 8 October 2001 (17:06) the spacing of a web of corrugated board.

The apparatus seen in Fig. 1 purely diagrammatically shows two machines 1, 2- roughly outlined by two stands for the manufacture of single-faced corrugated board. Both machines deliver a single-faced web of corrugated board 3, 4, the corrugated layer 5 or 6, respectively, of which is turned downwards. Each of the two webs of corrugated board 3, 4 has a smooth upper liner 7, 8. Machines of the species for the manufacture of single-faced webs of corrugated board are generally known, for instance from EP 0 687 552 A (corresponding to U.S. patent 5,632,850) or DE 195 36 007 A (corresponding to GB 2,305,675 to which reference is made for further details.

The two machines 1, 2 are followed by a web-control station 9, on which a braking roll 10 and 11 for each web of corrugated board 3, 4 is disposed, each of which being drivable by a torque motor 12 and 13. A deflection pulley 14 is disposed downstream of each braking roll 10 and 11, respectively, in such a way that each web of corrugated board 3 and 4 is led by an angle of contact of i approximately 180' around the respective braking roll 10 and 11.

A preheater 15 is disposed downstream of the web-control station 9, comprising a heating cylinder 16, 17 which the respective web of corrugated board 3 and 4 is guided along by its liner 7 and 8. An unroll stand 18 for a lower liner 19 oo 20 :is provided in the lower portion, a heating cylinder 20 for the lower liner 19 being •disposed downstream of the unroll stand 18. Deflection pulleys 21 are allocated to 00o0 the heating cylinders 16, 17, 20 in such a way that the webs 3, 4 and 19 are led along the heating cylinders 16, 17, 20 by a great angle of contact.

Gluing devices 22, 23 are disposed downstream of the two heating cylinders 16, 17 for the webs of corrugated board 3, 4, each comprising a deflection pulley 24 and 25, respectively. A glue spreading unit 26 and 27 is disposed downstream of the deflection pulleys 24 and 25, in which glue is spread on the tips of the corrugation on the crests 28, 29 of the corrugated layers 5, 6 turned away from the respective liner 7, 8. A heating device 31 is provided downstream of the glue spreading units 26, 27 in the direction of production 30, the webs of corrugated Melboume\003916782 Printed 8 October 2001 (17:06) board 3, 4 and the lower liner 19 there being brought' together and united. The heating device 31 has a stand 32 with a plane horizontal plate 33, underneath of which heating elements 34 are provided. Several pressure elements 35 are provided one after the other in the direction of production 30 above the plate 33, by means of which the entirety of the two webs of corrugated board 3, 4 and the lower liner 19, while conveyed through the heating device 31 in the direction of production 30, are pressed on the plate 33 so that they are glued together without however the corrugations of the corrugated layers 5, 6 being destroyed. In this case, the corrugated layer 5 is joined to the liner 8 and the corrugated layer 6 to the liner 19.

For the webs of corrugated board 3, 4 and the lower liner 19 to be fed collectively into the heating device 31, feeding rolls 36, 37 are provided thereon. These heating 4 devices 31 are known for instance from EP 0 623 459 BI (corresponding to U.S.

patent 5,456,783). Instead of this heating device 31, a heating device may be used as illustrated and described in DE 198 11 858 A.

15 As seen in Fig. 2, the upper web of corrugated board 3 and the lower web of corrugated board 4, when fed into the heating device 31, are to be brought together in such a way that the crests 28, turned away from the liner 7, of the corrugation 38 .of the corrugated layer 5 of the upper web of corrugated board 3 are in the same position in the direction of production 30 as the respective troughs 39, adjoining the 20 liner 8, of the corrugation 40 of the corrugated layer 6 of the lower web of °corrugated board 4. As further seen in Fig. 2, the corrugations 38 and 40 are to have an identically dimensioned spacing a and b, respectively. Their amplitudes c and d may vary. Wherever a crest 28 and a trough 39 are close to each other, a joint 41 is formed by gluing, with the liner 8, which now constitutes an intermediate layer of the finished 5-layer corrugated board 42, being incorporated therein.

To this end, a device 43 and 44 for the detection of the spacing a and b is allocated to each web of corrugated board 3, 4 upstream of the glue spreading unit 26, 27. Of these devices of identical design, Fig. 3 illustrates only details of the device 44 that is allotted to the web of corrugated board 4. In this case, two laser sensors 45, 46 are provided, which are disposed on both sides of the web of Melbourne\003916782 Printed 8 October 2001 (17:06) corrugated board 4. A sensor 45 is allocated to the liner 8; whereas the other sensor 46 is allocated to the corrugated layer 6.

Both sensors 45, 46 are connected to the inlets of an evaluation equipment, 47, the outlets of which being again connected to the inlets of a control equipment 48. The evaluation equipment 47 may moreover be provided with a display unit 49.

The torque motor 13 of the braking roll 11 is triggered by the control equipment 48.

In like. manner, the device 43 is connected to inlets of the evaluation equipment 47 which, in this regard, emits signals to inlets of the control equipment 48. The latter is again connected to the motor 12 of the braking roll The mode of operation of the device 44 is as follows: The sensor 45 permanently measures the distance e of the liner 8 from the sensor 45. This distance e ought to be permanently constant; however it is not, rooo because the web of corrugated board 4 slightly flutters. The sensor 46 allocated to oo oo the corrugated layer 6 permanently measures the distance f of the corrugation from the sensor 46. The values e and f are continuously fed to the evaluation unit poo 47. The distance g of the sensors 45, 46 from each other is fixed in the evaluation equipment 47.

be..

~Each time the sensors 45, 46 detect a trough 39 of the corrugated layer 6, gef is at a minimum. The same applies to the device 43, which scans the web of S 20 corrugated board 3 in the same way, with the maximum of the relation gef being detected there; this means that a crest 28 is detected there, which has to be rendered •congruent with a trough 39 of the web of corrugated board 4.

The velocity of the web of corrugated board 3 and 4 is known from corresponding feedback of the motors 12, 13 to the control equipment 48 and from there to the evaluation equipment 47. In this way, detection is possible also of the spacing a of the web of corrugated board 3 and of the spacing b of the web of corrugated board 4.

In order for the spacing a and the spacing b to be identical to have the same amount, and for the crests 28 of the corrugated layer 5 of the web of corrugated board 3 to be in congruence with the troughs 39 of the corrugated layer 6 Melbourne\003916782 Printed 8 October 2001 (17:06) 8 of the web of corrugated board 4, the proceeding is as follows: As seen in Fig. 4, the machines 1 and 2 manufacture the webs of corrugated board 3 and 4 in such a way that the spacing b of the web of corrugated board 4 is slightly smaller than the spacing a of the web of corrugated board 3. The spacing b is smaller than the spacing a by such an amount that even in consideration of the fluctuations anyway occurring during manufacture, the spacing b is always smaller than a. To this end it is regularly sufficient that 0.97a b 0.995a applies. Consequently the spacing b is by to 3% smaller than the spacing a. These dimensions are given on the corrugated board machines 1 and 2. Corresponding to the factual dimensions a and b detected by the device 43, 44, the motor 13 of the braking roll 11 is triggered in such a way that by corresponding torque increase, the liner 8 of the web of corrugated board 4 is elongated without getting torn. For this to be possible, it is more extendible than the liners 7 and 19. It must be possible to elongate the liner 8 by 2% to 12% without it getting torn. Paper may be used for the liner 8, which is 15 thinner than the paper conventionally used for the manufacture of corrugated board.

It is sufficient if paper of 60 to 80 g/m2 is used for the liner 8. This way of elongation of the liner 8 and thus of the web of corrugated board 4 helps enable the o*ooo spacing b to be equal to the spacing a. The control equipment is run in such a way that the maximum of gef in the device 43 and the minimum of gef in the device 44 :are synchronized, which also helps attain the congruence of a crest 28 and a trough 99999* 39 at a joint 41 as seen in Fig. 2.

Instead of the laser sensors 45, 46, sensors may be used which scan the web 9 of corrugated board 3 and 4 by ultrasonics and therefrom determine the mentioned values.

Fig. 5 illustrates another device 44' for the detection of the spacing b and a, respectively, comprising an accelerometer 50 which, by means of a tracer 51, bears by a given force against the side of the liner 8 that is turned away from the layer 6.

Between two troughs 39 of the corrugation 40, the liner 8, when running past the tracer 51, is impressed slightly more strongly than in the area of higher rigidity of the respective glued joint 41. Consequently, the accelerometer 50 receives the Melbourne\003916782 Printed 8 October 2001 (17:06) greatest acceleration pulse precisely at the joints 41. In this way, the accelerometer can detect the spacing b and also the accurate position of the joints 41 the troughs 39. Detecting the spacing a of the web of corrugated board 3 takes place in the same way by the device 43'. Processing the detected signals and triggering the motors 12, 13 and thus the braking rolls 10, 11 takes place in the same way as in the first embodiment.

e* *o*o ooo* Melbourne\003916782 Printed 8 October 2001 (17:06)

Claims

1. A method for the manufacture of at least 4-layer corrugated board which comprises an upper smooth first liner, a smooth intermediate layer, an upper first corrugated layer disposed between the upper first liner and the intermediate layer and glued thereto, and a lower second corrugated layer disposed below the intermediate layer and glued thereto; a) conveying a single-faced first web of corrugated board in a direction of production, including the smooth first liner and the first corrugated layer with a first corrugation and crests and a first spacing; b) conveying a single-faced second web of corrugated board in the direction of production, including the smooth intermediate layer as a second liner and the second corrugated layer with a second corrugation and crests and troughs S.. 9* ::and a second spacing, the first corrugated layer being turned toward the second liner and the second spacing of the second corrugated layer being slightly smaller than 15 the first spacing of the first corrugated layer; c) measuring the first spacing of the first corrugated layer; d) measuring the second spacing of the second corrugated layer; 9**9*9 e) said second web of corrugated board being elongated in the direction of production in dependence on the measured first spacing and the measured second •e 20 spacing such that the second spacing becomes equal to the first spacing;

9.. f) detecting the position, in the direction of production, of the first corrugation of the first corrugated layer relative to the position of the second corrugation of the second corrugated layer; g) the first web of corrugated board and the second web of corrugated board being displaced relative to each other in the direction of production such that the crests of the first web of corrugated board are synchronized with the troughs of the second web of corrugated board; h) applying glue to the crests of the first corrugated layer; and i) bringing the first web of corrugated board and the second web of corrugated board with applied pressure to join the webs to each other. Melbourne\003916782 Printed 8 October 2001 (17:06) 2. A method according to claim 1 wherein the second liner, which serves as an intermediate layer, consists of paper that is more extendible in the direction of production than the paper that constitutes the first liner. 3. A method according to claim 1 or 2, wherein the second liner is extendible by 2% to 12% in the direction of production without getting torn. 4. A method according to claim 1, 2, 3, wherein glue is spread on the crests of the second corrugated layer; and in that the third liner is supplied and brought together with the second web of corrugated board and joined thereto. A method according to any preceding claim wherein measuring the spacing of the first corrugated layer, measuring the second spacing of the second corrugated layer and detecting the position of the first corrugation of the first corrugated layer relative to the position of the second corrugation of the second corrugated layer take place simultaneously in the direction of production. 6. The method of any preceding claim, substantially as hereinbefore described. 15 7. An apparatus for putting into practice the method according to one of claims S:i- 1 to 6, including: a) a device for the supply, in a direction of production, of a single-faced o first web of corrugated board, which comprises the smooth first liner and the first corrugated layer with a first corrugation and crests and a first spacing; 20 b) a device for the supply, in the direction of production, of a single- •go* faced second web of corrugated board, which comprises the smooth intermediate layer as a second liner and the second corrugated layer with a second corrugation and crests and troughs and a second spacing, with the first corrugated layer being turned toward the second liner and the second spacing of the second corrugated layer being slightly smaller than the first spacing of the first corrugated layer; c) a device for the detection of the first spacing of the first corrugated layer; d) a device for the detection of the second spacing of the second corrugated layer; e) a device for the elongation of the second web of corrugated board in Melbourne\003916782 Printed 8 October 2001 (17:06) 12 dependence on the detected first spacing and the detect'ed second spacing in the direction of production such that the second spacing becomes equal to the first spacing; f) a device for the detection of the position of the first corrugation of the first corrugated layer relative to the position of the second corrugation of the second corrugated layer in the direction of production; g) a device for the displacement of the first web of corrugated board and the second web of corrugated board relative to each other in the direction of production such that the crests of the first web of corrugated board are in congruence with the troughs of the second web of corrugated board; h) a gluing device for glue to be spread on the crests of the first corrugated layer; and oi) a device for bringing together, pressing on, and joining to, each other the first web of corrugated board and the second web of corrugated board. 15 8. The apparatus of claim 7, wherein at least a device for the detection of the spacing of a corrugated layer comprises two sensors, which are disposed on both sides of the web of corrugated board and a first sensor of which is designed for •o.ooi S"measuring the distance of the liner from the first sensor; and a second sensor of which is designed for measuring the distance of the corrugated layer from the S 20 :second sensor. 9. The apparatus of claim 7 or 8 wherein the sensors are designed for non- 0..contact measuring. The apparatus of claim 9 wherein the sensors are laser sensors.

11. The apparatus of any one of claims 7 to 10, wherein at least a device for the detection of the spacing of a corrugated layer comprises an accelerometer.

12. The apparatus of any one of claims 7 to 11, wherein the device for the elongation of the second web of corrugated board comprises a braking roll.

13. An apparatus for making corrugated board substantially as hereinbefore described with reference to the accompanying drawings. Melbourne\003916782 Printed 8 October 2001 (17:06)