NO131414B - - Google Patents

Description

Method for impregnating corrugated cardboard and equipment for carrying out the method.

The invention relates to a method for impregnating longitudinally, horizontally moving corrugated board with at least one flat material layer and a corrugated material layer, which together with the flat material layer form channels which are open at both ends, and which extend in the transverse direction of the corrugated board, whereby the impregnating agent is supplied to it one end of the channels and flows through them and is sucked out at the other end.

From the U.S. patents no. 1,592,824 and 3,343-977, there are known methods for impregnating corrugated cardboard. With these known methods, the impregnating agent is passed through the corrugated cardboard channels in the form of a liquid stream. The corrugated cardboard is placed on its edge, so that its channels run vertically. In both cases, the flow of liquid through the channels is achieved by gravity, whereby in the U.S. patent no. 1,592,824 gravity is also supported by a suction effect.

These two methods are not suitable for supplying an impregnating agent to a corrugated board that moves at high speed along a production street in the shortest possible time, as the impregnating agent flows as a liquid stream through the corrugated cardboard channels. However, a liquid stream can only be set in motion with great difficulty, and for this reason it is also suggested by the known methods to place the corrugated cardboard on top. In a production street, however, it is desired that the corrugated cardboard moves horizontally. Furthermore, with a liquid impregnating agent, it is hardly possible to influence the degree of impregnation.

The aim of the present invention is to achieve a method for impregnating corrugated cardboard, which consists of several layers of material lying on top of each other, between which channels are formed, in which method corrugated cardboard can be impregnated without it being removed from the production line and especially without its horizontal position is changed. The invention also aims to provide a device for carrying out the method. Procedures and equipment must thereby also be able to be used, or incorporated into existing production streets. One must thereby imagine that the corrugated cardboard is moved along the production line at high speed, approx.

100 meters per minute, and that with existing production streets there is not much space available for extra handling of the corrugated board web. A method therefore had to be found with which a supply of impregnating agent to the corrugated cardboard can be achieved in the shortest possible time. At the same time, a homogeneous distribution of the impregnation agent would be achieved, whereby the strength, respectively the degree of the impregnation should be adjustable.

It was recognized that if a mixture of particles of impregnating agent and a gaseous and/or vaporous transport medium is brought into flow in the channels of the corrugated board by means of pure suction, it would be possible in the shortest possible time with a perfect distribution of the impregnation agent in the corrugated cardboard as well as an adjustable impregnation.

The invention thus relates to a method which is characterized by the fact that the impregnating agent is introduced together with air, gas or steam, as the cardboard is moved along the production line in a horizontal position.

The mixture containing the impregnating agent is transported along the inner wall surfaces of the corrugated board, whereby the impregnating agent deposits on the wall surfaces during transport. After completed deposition, the impregnating agent penetrates automatically into the material.

By changing the concentration of impregnating agent in the mixture and by varying the speed with which the mixture is moved through the channels, the amount deposited on the walls per unit area be affected in a simple way. -Such an impregnation method does not stand in the way of a high throughput speed for the corrugated cardboard web in the production street. Thanks to the small specific mass, the mixture of impregnating agent particles and gas and/or steam can be accelerated very quickly and thus moved across the width of the corrugated board's surface within a very short time. The mixture can thereby be provided immediately in front of one end of the corrugated cardboard's channels of a liquid or solid impregnating agent and a suitable carrier medium.

The device for carrying out the method comprises

a supply device and a suction device for the impregnating agent and is characterized by the fact that the supply device and the suction device each have guide channels running in the direction of travel of the corrugated board web, which lie opposite each other at a distance from each other and are open to each other in order to grip under and over each of the longitudinal edges of the corrugated cardboard, whereby the corrugated cardboard is held horizontally and that the guide channels form the outlet for the supply device, respectively the inlet for the extraction device, and that in front of the outlet for the supply devices a spray device is placed to provide a misting blanket, consisting of a mixture of impregnating agent and air , gas or steam, which atomization blanket is sucked in through the outlet in the corrugated cardboard channels with the help of the suction devices.

As an impregnating agent, in principle all suitable impregnating substances come into consideration, e.g. plastic, water glass, bitumen, paraffin, resin, glue, paraffin-bitumen emulsion, synthetic resin-wax mixture, liquid plastic, foamed plastic, synthetic resin, silicone, sodium silicate solution, alkali metal silicate, vinyl resin, etc.

In the following, the invention will be described in more detail with reference to examples of embodiment shown in the drawing, which show: fig. 1 a schematic view of an impregnation device according to the invention,

fig. 2 a plan view of a corrugated cardboard web which is passed through the device in fig. 1,

fig. 3 a cross-section of the intake element in the device of fig. 1,

fig. h a cross-section of the suction element in the device in fig. 1,

fig. 5 a partial section showing the sealing of the edge of the corrugated cardboard web when it is passed through the impregnation device,

fig. 6 and 7 flow diagrams for the impregnation in the device of fig. 1, where the impregnating agent is introduced from one side of the device,

fig..8 and 9 flow diagrams for impregnation where the impregnation agent is supplied from two opposite sides of the device,

fig. 10 a perspective view of an element used on the suction side of the device,

fig. 11 a cross-section of a suction element used in the device according to the invention,

fig. 12 a cross-section of an intake element,

fig. 13 a perspective view of a suction element where the guide part has been removed,

fig. 14 is a perspective view of an intake element with the guide parts removed,

fig. 15 a cross section of a compressed air nozzle,

fig. 16 a cross-section of a closing screw for the nozzle bore,

fig. 17 a cross-section of an atomizing nozzle for air and impregnation material,

fig. 18 a cross-section of another embodiment of a nozzle,

fig. 19 a cross-section of a pressure nozzle for atomized impregnating agent, and

fig. 20 a further flow diagram for the impregnation method according to the invention.

At the one in fig. 1 shown impregnation device 1 in a corrugated cardboard machine, the corrugated cardboard web 2 runs with its longitudinal edges partly through a guide channel or inlet strip 3 and partly through a further guide channel or suction strip 4, which guide channels or strips are designed as elongated, divided houses. Entry list 3

is provided with guide rails 3 for guiding the corrugated cardboard web 2. The guide rails 5 carry sealing lips 6 of elastic material on their longitudinal edges towards the upper and lower sides of the corrugated cardboard web 2. In a similar way, there are also sealing elements 7 arranged against the corrugated board at the end of the inlet strip, see fig. 2. On the entrance side of the inlet strip 3, a void zone 8 (fig. 2 and 6) is connected to the sealing element 7 (fig. 2 and 6) which is connected to the suction box 32 by a suction line 12. Adjacent to this vacuum zone 8 is an introduction zone 9 with an impregnating agent inlet 14, which via throat organs 15 (fig. 3) can be regulated with adjusting screws 16. A pressure zone 10 for hot compressed air supply joins the introduction zone 9 and to the pressure zone 10 another pressure zone 11 for cold compressed air supply. For the hot and cold compressed air, the adjustable inlet 17 is arranged (fig. 2). In the area of the impregnating agent inlets 14, electric heaters 18 are arranged for the inlet strip 3 (fig. 3). The impregnating agent is led through a line 19 from an impregnating agent container 20. If the vacuum is removed, the rest of the impregnating agent flows to a drain container 13 - The inlet strip 3 is adjustable by means of a flange 21 on the stand of the corrugated cardboard machine and can be adapted to the edge of the corrugated cardboard web 2.

Guide rails 22, 23 are built into the elongated suction strip 4 to guide the other edge of the corrugated cardboard web 2, which extend out of the housing 4 through a longitudinal slot 24 serving for the introduction of the corrugated cardboard. The longitudinal edges of the guide rails 22 projecting outside the longitudinal slot, 23 carries flanges 22', 23', which abut against the outside of the housing 4. The flange 23' is screwed together with the housing wall by the suction strip 4, while the flange 22' can be adjusted with the help of guide grooves 25 in relation to the screw bolt 26 on the suction strip 4 and fixed in the set position by means of the nut 27, so that a regulation of the guide space between the guide rails 22, 23 is achieved. Elastic sealing lips 28 are attached to the flanges, which protrude beyond the outer longitudinal edges of the guide rails 22, 23 and rest against the underside and upper side - that of the corrugated cardboard web 2. The reference number 29 denotes air extraction holes arranged near the outer longitudinal edges of the guide rails 22, 23. The suction strip 4 consists of separate chambers, which are provided with suction nozzles 30 (fig. 4), which according to fig. 1 by means of hoses 31 is connected to the corresponding chambers in the suction box 32. The latter is connected by means of lines 33 to a vacuum pump 34 (and if necessary with additional suction units), which is driven from an electric motor 35. The suction box 32 serves as a vacuum chamber . The outlet of the suction pump 34 is connected by means of a connecting pipe 36 to an impregnating agent separator 37} from which the recovered impregnating agent is supplied by means of a return line 38, which is only partially indicated, to a collection container 39. From this, the recovered impregnating agent is fed through a line back to the impregnating agent container 20.

The impregnation itself takes place in the following way:

The finished corrugated cardboard web 2 runs with its two longitudinal edges showing the open wave channels through the impregnation device 1 at a speed of 60 - 120 meters per minute, the longitudinal edge sections of the corrugated cardboard web 2 being guided partly in the inlet strip 3 and partly in the suction strip 4 under tight closure. The suction strip 4 ensures the removal of air in the wave channels. In the suction strip 4, an unregistered heating device is built in, so that the impregnation liquid does not condense and thereby cause clogging. Thanks to the 2-3 meter long suction line's 4 evenly distributed suction nozzles 30, there is a uniform vacuum in the list, which is produced by the vacuum pump 34. As the suction box 32 also acts as a liquid separator, no impregnating agent can enter the pump 34 From the likewise heated separator 37, the separated impregnating agent is fed back into the impregnating agent tank 20 by means of an undrawn, heated pump system, so that a closed circuit for the impregnating agent is formed. The air purified from the impregnating agent in the separator is then supplied to the compressed air devices on the inlet strip to utilize the pump's drive pressure. Under the action of the vacuum created by means of the suction strip 4 in the 2 wave channels of the corrugated cardboard web, the impregnating agent is drawn

in the area of the zone 9 (Fig. 6) into the wave channels of the corrugated cardboard web 2. Thanks to the heating device 18 for the inlet strip 3, the impregnating agent has the desired high temperature when it penetrates into the wave channels. Due to the high speeds, which are necessary for a profitable corrugated cardboard production, the impregnation device is also built with a view to high performance and is therefore equipped with aggregates arranged for maximum performance. Due to the speed of movement of the corrugated cardboard web 2 and the speed of movement of the impregnating agent in the corrugated channels produced during the suction effect of the suction strip 4,

more the continuous, diagonal flows from the inlet strip 3 to the suction strip 4 which together form a flow band 9'• The subsequent hot compressed air zone 10 and cold compressed air zone 11 ensure the drying of the wave channels moistened with impregnating agent

As the cover sheets for the corrugated board.2 are porous, it needs

into the wave channels in the evacuated state a considerable amount of so-called false air, which flows through the pores in the cover sheets and into the wave channels, which causes a significant vacuum loss. Experiments have shown that a fine (thin) film of water applied in front of the impregnation device to achieve an impregnating substance-free surface at the same time provides a good sealing of the pores and thus ensures that the vacuum is maintained.

Sealing of the corrugated board can also be achieved by other suitable measures of a mechanical nature, e.g. by arranging shielded vacuum zones above and below the corrugated cardboard, or by placing cover-foil webs, which are rolled off successively from rollers.

There are different ways to guide the impregnation liquid into the horizontally passing corrugated board path 2.

According to a first proposal, the impregnating agent in the form of a liquid blanket is allowed to flow past in front of the wave channel mouths. As soon as the wave channels are now under vacuum, the impregnating agent is sucked into the wave channels.

According to another proposal, a loosely-ended suction strip is placed on the inlet side of the wave channel mouths, which is bent slightly downwards, so that the vacuum pulls the impregnating agent brought to the suction strip upwards and sucks it through the wave channels.

According to a third proposal, the leveled liquid mirror is brought up to the level of the corrugated cardboard to be impregnated, so that the vacuum sucks in the agent.

According to a fourth proposal, the impregnating agent penetrates by force of its own fall with the help of a specially designed for this purpose, well-sealing and during lateral movements and displacements of the corrugated cardboard web pressing introduction device into the corrugated channels and is conveyed from there by suction.

With the same effect as according to the latter proposal, adjustable dosing pumps can be built into the introduction device, which press the impregnating agent with adjustable pressure into the wave channels or inject it using nozzles.

In all of the inlet possibilities described so far, the inlet length varies from case to case. However, there is always a short, active or passive sealing zone 8 (fig. 6) in front of this inlet section, which allows a vacuum to build up.

The impregnating agent drawn into the corrugated channels during the passage of the inlet section forms in them small continuous columns of liquid, which together form a diagonally extending sealing strip 9' (fig. 2 and 6) over the entire width of the corrugated cardboard during their passage, which by its diagonal continuous flow de- creates the corrugated board web in two vacuum zones, whereby the vacuum acting on the suction side has a pulling effect, and the vacuum that builds up on the inlet side has a braking effect.

As this braking effect is undesirable and can only occur when the entire inlet side is hermetically closed, it is necessary to allow supplied air to flow into the immediate connection to the inflow zone 9 (fig. 6) for the impregnating agent. As this air is already able to penetrate under normal air pressure and the desired vacuum on the other side of the diagonal liquid band 9' is still effective, it manages to accelerate the flow rate of the impregnating agent.

However, since this acceleration at the high driving speeds of normal corrugated cardboard machines is not sufficient for the short impregnation zone, the air supplied on the inlet side in connection with the inflow zone in zones 10 and 11 must be compressed air, such as via nozzles specially designed for this purpose under high pressure and high velocity immediately behind the impregnating agent in zones 10 and 11 (fig. 6) is blown directly into the wave channels. As this will, however, lead to a sudden cooling and slowing down of the impregnation process, the compressed air supplied in zone 10 must be preheated to at least 120°C. This hot compressed air fulfills the following functions: a) it accelerates the impregnating agent, b) with its heat, it prevents too strong condensation of the impregnating agent due to too rapid cooling, and thus ensures an economical consumption of liquid impregnating agent, c) thanks to its high flow rate and the pressurized air quantity cleans the wave channels and blows out all residues of impregnating agent in a timely manner.

Por the subsequent imperative necessary cooling off

the impregnated wave channels, a cold compressed air zone 11 is connected immediately adjacent to the hot compressed air zone 10, which cold compressed air subsequently disappears out of the wave channels open on both sides of the path 2.

The same cooling purpose also serves, in the case of a cover sheet moistened with a water film, a ventilation of the same with an externally acting, hot or cold air current, which causes a rapid evaporation of the water film and thereby an intense cooling of the corrugated board.

In accordance with the temperature of the impregnating agent, the inlet and suction strip are also heated. -Thereby, on the inlet side, the temperature of the medium required for the impregnation is maintained. On the suction side, however, impregnating agent residues do not solidify, but enter the separator in liquid form and from there return to the inlet side. This applies above all to hot-melting media and hot sprays.

In order for the vacuum pump 34 to be able to unfold its full effect, it is advantageous to suck the main amount of air at the entry of the corrugated cardboard into the impregnation station as before, by means of a separate fan continuously out of the corrugated channels.

The impregnation device is designed in such a way that it can be connected as a high-performance unit to any available corrugated board machine between the short transverse cutter 4l (fig. 6) and the "Triplex machine" 42, or in new machine plants be built in as a fixed component of the same. However, the device can also be built in above the last heating plates

in the drying system of the corrugated board machine, which can be important with cold, watery plastic emulsions.

As the so-called multi-corrugated corrugated cardboard is made up of waves of different sizes and thus has different wave layer heights, it is necessary to provide for each wave layer a separate adaptation and regulation of the impregnating agent flow. Thus, for example, the flow conditions in the large waves (A-wave) are completely different than in the finer waves (B-wave). The large wave needs a shorter inlet section, as it can take up more impregnating agent at once, and this impregnating agent achieves a much greater flow rate than in a small wave thanks to the better flow conditions. It is therefore necessary to feed the wave layers separately with impregnating agent by means of a separate inlet arrangement adapted to the different nature of the waves.

If you want to avoid this complication, there is a possibility

to introduce the impregnating agent in the most favorable flow, i.e. in the rough corrugated layer of a multi-corrugated cardboard, as the intermediate cover sheets, in order to achieve easy and quick penetration of the adjacent corrugated layers, must consist of particularly thin, absorbent material.

■ A further particularly appropriate possibility is the arrangement of two or more equal-sized corrugated layers in the corrugated board, which is possible thanks to the stabilizing effect of the impregnating agent. In this case, the wave layers must be driven in in the most statically advantageous arrangement, so that the wave crests rest on other wave crests. In this way, all corrugated layers can be treated under the same conditions by the same unit and impregnated at the same time. Particularly important is the repeated application of the same wave size in processes for foaming the wave channels, as the hardened plastic skin provides completely new stabilization conditions.

The penetration depth of the impregnating agent depends on various factors. It can thus be influenced by changing the speed at which the impregnating agent runs through the corrugated cardboard web, and also by changing the temperature of the impregnating agent. Furthermore, the penetration depth can be affected by temperature changes of the air required for the various purposes, and also by the amount of air and the pressure. The speed of the impregnating agent flowing through is again dependent on the strength of the applied vacuum. This can again be influenced by external wetting with a water film or by prior internal steam flow through the wave channels. Furthermore, it is possible to stop the penetration (and thus the penetration depth) of the impregnating agent by providing an intense evaporation of the water film from the outside, whereby the corrugated board cools. Furthermore, the depth of penetration depends on the speed at which the corrugated board is produced, and further on the different types of impregnating agent and their viscosity.

Taking these factors into account, any desired impregnation is possible with the most diverse types of corrugated board. Thus, for example, it is possible to effect a complete impregnation of corrugated cardboard, which can be distinguished by a darker color on both sides, as the color is of course dependent on the agent chosen. Furthermore, it is possible to produce a partially impregnated corrugated cardboard, in which both cover sheets are "bright". Another type of partial impregnation consists of . in that the corrugated cardboard is "light" on one side and "dark" on the other side, or that one side is completely impregnated and the other side partially impregnated, whereby, as needed, free surfaces can be obtained for applying pressure or gluing. Sheets free of impregnating agent can, as previously mentioned, be achieved by intentional wetting. In this case, the corrugated board has on one side a "dark" cover sheet and on the other side a cover sheet with "dark" and "light" parts. Such a partial impregnation can also be carried out in such a way that the corrugated cardboard has "dark" and "light" areas on both sides, the latter having been achieved by partially applying a water film from the outside. These bright fields can be printed or glued on if desired. In the case of multi-corrugated corrugated cardboard, only one corrugated layer can also be treated with an impregnating agent, so that only the layers that need the impregnation most, namely the outer layer and possibly also the inner layer, are completely or partially impregnated, resp. impregnated.

As the outside air penetrates through the vacuum prevailing in the corrugated spaces with high pressure through the pores in the corrugated cardboard sheets and thus causes a relatively rapid "filling" of the vacuum with so-called false air, it is appropriate to slow down this process by suitable measures. This can, as already mentioned, be achieved during the entire run of the corrugated cardboard by continuously applying a permanent water film to form a hole-free membrane. As is known, this precaution also serves to keep the outermost layer of the cover sheets free from the influence of the impregnation medium. The wetting before, during and after the impregnation is caused by hot impregnation agents that the protective water film is maintained during the heat-dependent evaporation process and thus serves a dual purpose. The suction prevailing in the wave channels draws part of the water film into the paper pores, where it re-evaporates on contact with the hot medium. Due to the slow flow rate of water, a shield is formed against the following air, and by wetting the top layer of paper, the impregnating agent is prevented from penetrating completely through the cover sheet.

As the corrugated cardboard's high speed of movement implies a short wetting duration, the water is softened (soft) by additions, in order to increase its penetration ability. An increase in the water temperature also serves the same purpose.

A further possibility for achieving a reliable sealing of the cover sheet and a particularly deep penetration of the impregnating agent consists in applying an impregnating substance film-like to the corrugated cardboard cover sheets instead of water, and exclusively creating a vacuum in the interior of the corrugated cardboard. In a combination of both types of application, it can simultaneously be impregnated from the inside with a heat-melting medium, whereby from the outside an aqueous, cold-soluble plastic emulsion takes over the function of the water film in such a way that the emulsion's water content is evaporated by the heat from the "heat-melting" impregnating agent, so that a tough, unbreakable plastic outer layer.

A further possibility for reducing surface false air consists in shielding the same by sealing cavities placed above and below the impregnation zone. In their passive function, these cavities are evacuated with the help of the vacuum prevailing in the wave channels through the pores of the paper and form, as soon as they are empty of air, protective vacuum zones. However, this device can be made significantly more effective by having both the upper and lower protective shells with evacuated cavities have a direct vacuum connection to a fan or a vacuum pump. In this way, an internal vacuum can even be built up in strength superior to the external vacuum, so that in addition to a penetrating suction, a suction occurs from the inside outwards, which means that with great speed, e.g.

e.g. in the form of shower drops, flowing impregnating agent is also drawn from the inner area of the wave channels outwards to the paper layers and from there penetrates particularly intensively into the paper pores. Additional vacuum zones 8 serve to seal the false air inlets at the impregnation station's entrance and exit.

When regulating the vacuum conditions between inside and outside,

respectively the amount of false air that can still penetrate, the penetration ability of the impregnating agent can also be controlled. However, the corrugated board can also only be evacuated exclusively through the cover sheets.

With the same device for providing vacuum zones, one can conversely create pressure zones, through which reactive gases are pressed into the paper pores to cause a particularly intense reaction with a reactive impregnating agent that penetrates from the inside and the outside, thereby achieving both an improvement in the quality of the impregnation and a further opportunity to control the impregnation process.

With the help of heating plates above and below the continuous corrugated cardboard, it is possible to influence the false air penetrating into the pores of the cover sheet in the impregnation station. During the heating, the air above the papers is strongly heated, so that it rises. Thereby a pressure relief is achieved. The hot air penetrating the pores also keeps the impregnating agent warm for longer and, when the paper is strongly heated, ensures easy penetration of the impregnating agent. When impregnating agent introduced in powder or dust form, e.g. powdered paraffin, the hot air penetrating the paper pores causes an immediate melting of the individual particles.

Instead of heating plates, a device can also be used to generate a magnetic field which seeks to attract the previously opposite dielectrically polarized medium and thus lead to deposition on the paper layers. This method has proven particularly advantageous -with easily moving media, such as sprays, powders etc. To achieve the same purpose, metallic additions to the medium can also serve. The dielectric polarization of the impregnating agent can also be achieved -without magnets, as the corrugated cardboard itself already has a static charge, which is amplified by suitable measures and forms the opposite pole for the introduced medium which is equivalent.dielectrically polarized.

For the implementation of all impregnation methods, it is important that well-sealable seals (e.g. elastic sealing lips) are arranged both on the inlet side and on the suction side, i.e. they press against the corrugated board. At the ends of the guide strips 5> or 22, 23 there are arranged sealing lips 6, resp. 28 of wavy material, so that under the influence of the suction they press against the continuous corrugated cardboard. Instead of sealing lips, the guide strips 5, resp. 22, 23 have narrow sealing chambers 5' (fig. 5) extending in the flow direction of the corrugated board, which cut easily into the cover sheets of the continuous corrugated board and thereby form a rather fine groove. The side inlets for the corrugated board are also provided with flexible, pressing sealing elements. A particularly good seal is achieved by means of an inlet and suction unit which continuously adapts to horizontal displacements of the continuous corrugated cardboard web.

Sprays form a particularly economical way of introducing a liquid impregnating agent into the channels of the corrugated board. Through the exiting compressed air from slot nozzles placed immediately behind an impregnating agent blanket, this can be atomized within the inlet strip 3-The nozzles are thereby arranged at short distances from each other directly behind the liquid blanket in the direction of the wave center. The spray system thus formed is located according to fig. 7 at the beginning of the inlet side in zone 9, which joins closely to the evacuated zone 8. The impregnating agent can also be sprayed air-free into the wave channels with the help of a special unit under high pressure and finest atomization, which enables a particularly ■ intense humidification. The impregnating agent can also be mixed with air in the most intensive manner (e.g. according to the spray gun principle) and sprayed directly into the wave channels.

When applying. of. spray of any kind also fundamentally changes the conditions and conditions in the channels of the corrugated cardboard. Thus, the sealing function of the through-flowing liquid columns is completely eliminated. In addition, the flow conditions change, as the braking effect of the direct contact between the impregnating agent and the corrugated inner rafts falls away. The friction that is thus generated is so great in the case of liquid columns that, e.g. the liquid columns move at a speed of only approx. 2 meters per second, in stark contrast to the speed of compressed air which reaches values of 80 meters or more per second. This difference also explains the large acceleration achieved by the introduction of compressed air for liquid media behind the liquid columns. If now any braking effect is eliminated, as is the case with sprays, the high speed that occurs thanks to the nozzles and the high pressure necessary for the atomization can be achieved without hindrance. The thus accelerated spray ends up in the wave channels by the suction effect of the vacuum pump, which prevents a loss of speed. During this process, these fine spray droplets wet the inner surfaces of the corrugated cardboard on its way from zone 9 to the suction zone 4' (fig. 7)5, which happens in the most economical way (material saving). By preventing an excessive loss of spray agent due to unused spray amounts, the spray agent (spray) can be set in a swirling motion with the help of special nozzles, so that the spray droplets in the wave channels are flung out against the inner walls of the wave channels by centrifugal force.

A further advantage of the spray method is that the intensity of the impregnation can be regulated very finely, which allows a product-specific impregnation. This fine adjustment of the impregnation effect has a positive effect on the profitability of the method.

Above all, in the case of spray and steam impregnating agents, it is appropriate to replace the sharp division in the inlet and suction side with an arrangement of these active zones corresponding to these media. Thus, instead of placing these "functions" on separate sides, a parallel sequence of functions that alternates from side to side is intended.

At the one in fig. 8 embodiment, the corrugated channels are thus evacuated on the arrival of the corrugated cardboard web at the impregnation station for the contained air from both sides, the vacuum in immediate connection to this being "filled" (removed) from both sides with impregnation spray (mist, steam, gas etc.) In the collision between the two impregnating agent currents, a densification of the same is achieved, which enables a thorough and practically lossless utilization of the amount of impregnating agent used. To prevent a subsequent outflow of the compressed, volatile impregnating agent in this way during the continued flow, the wave channels are closed on both sides in the zones - HO, which are in immediate connection with the spray inflow zones 9. This sequentially divided parallelism of the unilaterally acting impregnation functions in the method according to Fig. 7 results in extreme corrugated board widths have the advantage that, despite the high speeds of the corrugated board, an impeccable proper treatment of its entire interior. In fig. 7 and 8 denote 8 the evacuation zones, 9 the spray inflow zones, 40 the closing zones, 4' (Fig. 7) an extraction zone and 11 (Fig. 7) a compressed air inflow zone.

For the previously mentioned purpose, it is also according to fig.

9 provided -a page switching function as in this case, rather than

all using liquid columns serve the same purpose. Hereby, the suction zones 4' and the inflow zones 9 are arranged on opposite sides in such a way that the impregnating agent can flow through each inflow zone 9 to at least half of the corrugated board width in the direction of the opposite suction zone 4'. In fig. 9, the closing zones 40 and a compressed air inflow zone 11 are also arranged. The opposite suction and inflow zones are mutually offset in the direction of movement of the corrugated cardboard web, the suction zone 4' on each side being separated from the inflow zone 9 by means of an end zone 40. The compressed air inflow zone 11 ensures, in cooperation with the opposite suction zone, to remove excess impregnating agent.

When impregnating using sprays, which have a high flow rate, it is appropriate to stop the flow of spray after the wave channels have been filled. This can, according to fig. 7 is best achieved with the help of a hermetically closed termination zone 40 on the inlet side immediately ending the spray zone 9, as well as an overlying (continuing) termination 40 ending with the suction zone 4'. The termination on the inlet side is joined by a compressed air inflow zone 11 which ensures cooling and drying of the impregnated wave channels. Between the two diagonally opposite end zones 40, an accumulation zone ending in the spray zone is formed, which gives the impregnating agent time to penetrate the paper layers. If, on the other hand, the paper layers are injected from both sides, as shown in fig. 8, then the two spray shocks meet in the middle of the corrugated board, and this automatically results in effective braking. Here, too, it is advantageous to mount an end zone 40 on both sides that ends with the inflow zones 9. These closing zones 40 prevent too rapid outflow of the injected impregnating agent. If it is sprayed with a cold impregnating agent, after the hermetic closure (closing zone) 40 on the inlet side, an inflow zone for hot compressed air must be arranged, which zone forms the closure on the inlet side and causes a rapid in-drying of the sprayed media. However, if it is sprayed with hot impregnating agent, cold compressed air must be used in the said compressed air inflow zone to cool and solidify the impregnating agent.

In order for a complete impregnation of the corrugated cardboard to enable a clean impression on it, the corrugated cardboard is already supplied shortly before entering the impregnation station with the relevant impression, whereby the printing ink used counteracts the penetration of the impregnating agent, so that a similar effect occurs as when applying a water film. Optionally, a water color can be used as printing ink. Both this printing device and the coating system can be built together with the impregnation station in such a way that they form a single machine unit.

An even finer step than spray is the evaporation of the impregnating agent and its subsequent blowing in as steam. Of particular importance here is vacuum evaporation, as the vacuum shifts the evaporation point. In this way, the impregnating agent in a vacuum container specially designed for this purpose can be made to evaporate, whereby the steam in more or less compressed form is sucked into the waves. However, the vaporous impregnating agent can also be blown in at such a temperature that it further evaporates from a state of fine atomization in the wave channels standing under vacuum.

When foaming corrugated cardboard with self-hardening foam plastic, the foam, if it is composed of two or more components, is mixed thoroughly immediately before it is fed into the wave channels, so that the foam enters the wave channels in homogeneous liquid form. Corrugated cardboard coated with plastic foam (foamed) and impregnated has an extremely high insulation value and is therefore particularly suitable for the transport of temperature-sensitive products, and also for use in the construction sector. The foaming of the corrugated channels also enables the use of corrugated cardboard with extremely large corrugations without any detrimental effect on the quality.

The impregnation station, resp. - the device according to fig.

10 - l6 again have an inlet or insert strip 3 and a suction strip 4, which consist of mutually replaceable and heatable standard elements of light metal. The suction and inlet strips 3, 4 are composed of at least two active and one passive part 8'. The latter corresponds to the one in fig. 6 showed void zone .8 and forms the insertion head 43 at the beginning of each strip 3, 4. The insertion head 43 ensures friction-free pick-up of the corrugated cardboard web end 2' and bends the protruding cover sheet 2'. of the latter (fig. 12) plow-like up, so that they can run into the therefore determined cavities 44, without causing any breaks. 44' denotes the impact rafts, against which the long sides of the corrugated cardboard web 2' come into contact, so that the openings of the corrugated cardboard's channels slide past in front of suction slots 49 (fig. 11), resp. nozzle openings 46 (fig. 12). In the guide head 43 (Fig. 10), the impact floats 44' simultaneously cause a sealing of the wave channels, which are then evacuated.

The two (or more) replaceable standard elements of the suction strip each have a closed, independent suction chamber 47 and each a suction nozzle 48. The standard element provided with the suction slot 49 (fig. 13) can be replaced as desired, not only on the suction side, but when extraction is arranged on alternating sides, also on the inlet side. The connection and guide elements 50 are then loosened, so that a block 51 can be easily pulled off from the through steam lines 52. The same is also possible with the block 51' provided with the nozzles 53 on the inlet side, as it has the same dimensions. Adjustably arranged and thus adaptable to any type of corrugated board are also the guide and connection elements 50 mounted on the end, which together with the sealing combs 54 and the distance and connection elements 55 form a fixed unit. This is only released when the sealing cams 54 have to be readjusted.

The inlet strip's 3 blocks 51' are likewise independent, self-contained units, which both for the impregnating agent and for the compressed air have their own pressure chambers 47 and supply lines 48. The stabilizing, connecting and guiding elements 50, 555 56. together with the steam lines 52 are continuous and forms a stable unit from the whole when screwed together. This is conveniently stored on a roller rail, not shown, and is adjusted by tension and compression springs on a light fitting seat at the wave end of the corrugated cardboard web 2. With this control, the inlet and suction strips 3, 4 can easily adapt to the movement of the one in motion. corrugated board. With the help of this property, the impregnation device ensures., resp. - the station has a high degree of efficiency in every phase of the corrugated board's passage.

Thanks to the separate suction and pressure chambers and the associated connections, it is possible, for example, on the suction side, connect one of the suction strip's 4 standard elements to a vacuum pump, while the other is connected to a fan, so that for adaptation to the desired operating conditions, variations can easily be implemented and. changes. The same also applies to the inlet strip 3 for the impregnating agent and the hot and cold air. The fine regulation of the individual components, on the other hand, takes place by replacing different nozzles 53 with others of greater or lesser capacity. For this purpose, the set screws on the front guiding and preventing elements 50, 55 must be loosened and the latter moved into not shown setting grooves in the blocks 51' in an upward and downward direction.• With the help of the slotted screw-in and screw-out nozzles 53 ( fig-14) is a required replacement of the nozzle set which can be carried out quickly.

A further control option for the impregnating agent can be achieved by inserting a known per se dosing pump, which is not registered. Both here and with compressed air, the various pressures acting on the impregnating agent are controlled.

At the two ends of the inlet and suction side, bearings can advantageously be arranged above and below to accommodate dampening rollers or sealing belts, the shafts of the latter being only held rigidly at one end in a bearing, so that the other end slides in the opposite storage and thus can adapt to the movements of the impregnation device.

Those in fig. 13 - 16 shown nozzles are formed by ordinary "Imbus<t:-> screws and are therefore relatively cheap. Fig. 17 shows a combined nozzle that works according to the spray gun principle. 53 denotes the one formed by the "Imbus" screw nozzle, in whose continuous cavity 57 extends a supply pipe 58 for the liquid impregnating agent. The supply pipe lies concentrically forming a space 59 in the cavity 57. The space 59 enables access of air from the pressure space 47, as indicated by dashed arrows 60. That from the space 59 outgoing compressed air thereby finely divides the impregnating agent flowing into the nozzles through the supply pipe so that a fine spray is formed.

For the production of plastic foam containing corrugated cardboard, separate machines can be used independently of the corrugated cardboard machine.

For the use of cold, aqueous plastic emulsions, it is advantageous to place the impregnation station above the last heating plates in the drying hopper of the corrugated cardboard machine, whereby the water contained in the emulsion evaporates to a sufficient extent on its way through the machine.

The impregnating agent and the corrugated cardboard impregnated through this or part of it can also be brought into a dielectric state for certain purposes.

It is possible to impregnate the corrugated cardboard during ongoing corrugated cardboard production on the corrugated cardboard machine in its full production width, and this just before the cardboard is cut and folded. This has the great advantage that all wave channel openings are open and are not affected by the flow of the impregnating agent. Only after the impregnation does the processing take place, resp. the shaping (shaping) of the corrugated cardboard using slitting and folding tools, whereby the folding channels are partially impressed. In the section in which the impregnation is carried out according to the present invention, the corrugated cardboard is already finished, but still has a certain moisture content and, above all, a temperature of 70 - 90°C, which is very important for the impregnation.

The different possibilities for the use of the impregnation agent and the impregnation methods are based on the requirements placed on the impregnated corrugated board. As an impregnation agent, e.g. a liquid, a spray, a vapour, a powder, a foam, a mist, a gas, dust, etc. The impregnating agent to be chosen can be a hot-melting or cold-soluble agent with volatile proportions. However, it can also be an emulsion or a foamed plastic.

The spray method is above all suitable for exclusively internal treatment of the corrugated board, as this method works with the finest degrees of wetting, so that there is the possibility of carrying out the impregnation in such a way that the outer layers of the corrugated board sheets are kept free of impregnating agent and later can be used for inscriptions, overprints etc. In contrast to this, impregnation methods with liquids are suitable for complete impregnation of all the paper layers of the corrugated board.

In the case of liquid impregnating agents, the used impregnating liquid can be sucked as liquid columns through the wave channels in the corrugated board web. However, they can also be foamed and as foam sucked through the wave channels. In contrast to the hardening foams, here is meant a foaming liquid, whereby the penetration of the foam enables a sparing, fine and regular wetting of the sheets with impregnating material, whereby the wave channels are free of foam residues during the drying of the impregnated paper layers.

When using a foaming plastic, the components are thoroughly mixed immediately before suction. After the plastic foam has been sucked through to the paper layers, the adhering residues completely fill the wave channels during the foaming process. This foam then hardens in the wave channels and causes an inseparable connection of all paper layers.

The impregnating agent can also be sucked through the wave channels as a spray or mist, during which spray with or without air is sprayed directly into the wave channels, or converted from spray in a (if necessary heated) spray densification chamber into a fine and moist mist and then sucked through the wave channels . The impregnating agent can also be injected (hot or cold) into a vacuum chamber and vacuum evaporated there. From this vacuum chamber, the moist impregnating agent vapor can then be sucked through the wave channels. Furthermore, the impregnating agent can be brought into a gaseous state with the help of a gasifier and thus, by suction, trigger a sealing reaction that connects the paper fibers to each other.

A special form of impregnation provides spraying of the corrugated channels with powder or dust-like impregnating agents, which, in the same way as for sprays in a finely atomized state, are introduced into the channels of the corrugated board and there, be it by the moisture content of the corrugated board, by dielectric polarization or mechanical influences from outside are brought to evenly distributed adhesion to the paper layers. This powdery impregnating agent develops its effect by entering into a connection with the components in the sheet (sodium) or by the melting effect caused by the corrugated board's own heat or by separately supplied hot air. A further possibility is the connection of the powdery, water-soluble impregnating agent with the moisture in the still fresh corrugated board.

A further device according to fig. 20 is for carrying out the method built into a corrugated cardboard machine of a conventional type, which in a known manner has a short transverse cutter 62 for the removal of not yet usable corrugated cardboard pieces (which above all occur when a new type of cardboard is introduced) and at a distance ( -3 m) from here has a longitudinal cutting and following device 63. In this space the impregnation and coating device is built in and is denoted by the reference number 64. It is equipped with two opposite, house-like designed guide strips 3, 4, which tightly enclose the longitudinal edge pair of the corrugated cardboard web 2. For this purpose, the longitudinal and transverse edges of the guide strips 3, 4 can be provided with sealing elements, e.g. elastic sealing lips or sealing chambers. The guide strips 3 are connected to a vacuum pump, with the help of which the air is sucked out of the corrugated cardboard channels, as a vacuum zone 65 is created within the two guide strips 3, 4 in the corrugated channels of the passing corrugated cardboard path 2. Above this zone 65 or, as shown, in front of this zone, a coating and impregnation device 64 is arranged above and below the corrugated cardboard web, by means of which the impregnation agent is continuously applied. The impregnating agent can be applied in liquid form by rolling, airless spraying, spraying or in a liquid blanket (only possible on one side from above). The thus applied impregnation liquid is, during the subsequent passage of the vacuum zone 65, by means of the suction acting in the wave channels and the air pressure acting from the outside, pressed in and sucked through the pores of the corrugated board's cover layer.

The corrugated cardboard impregnated in this way exhibits an impregnation which has penetrated deep into the corrugated cardboard's paper layer and which has made the corrugated cardboard rigid and waterproof.

Corrugated cardboard coated in this way has an impregnation layer that has penetrated deep into the pores of the cover sheets and is therefore particularly tough and water-repellent.

The impregnating agent used can be of any chemical or physical nature, for example in the form of powder, powder or dust.

The corrugated board produced according to the method is not only impregnated, but also significantly improved in quality with regard to firmness, longevity etc.

Claims (2)

1. Method for impregnation of longitudinally, horizontally moving corrugated board with at least one flat layer of material and a corrugated material layer, which together with the flat material layer forms channels which are open at both ends and which extend in the transverse direction of the corrugated cardboard, whereby the impregnating agent is supplied to one end of the channels and flows through them and is sucked out at the other end, characterized in that the impregnating agent is introduced together with air, gas or steam, the cardboard being moved along the production line in a horizontal position. 2. Device for carrying out the method according to claim 1 with a supply device and an extraction device for the impregnating agent, characterized in that the supply device and the extraction device each have a guide channel (3, respectively 4) running in the direction of travel of the corrugated cardboard web, which are opposite each other at a distance from each other and are open towards each other to grip under and over each longitudinal edge of the corrugated cardboard, whereby the corrugated cardboard is held horizontally, and that the guide channels form the outlet for the supply device, respectively the inlet for the extraction device, and that in front of the outlet of the supply device (3> 20 .) a spraying device is arranged to provide a pre-dusting blanket, consisting of the mixture of impregnating agent and air, gas or steam, which atomizing blanket is sucked in through the outlet in the corrugated cardboard channels by means of the suction device (32, 3).