EP0299020B1 - Wet treatment device for hides - Google Patents

Abstract

A device for treating hides with liquids in so-called wet processes, for example tanning, drenching, dyeing or the like, has a rigid, fluid-permeable support for the hide and a treating device that can be placed on the hide, essentially close to it, and which infuses the treating liquids under pressure into the hide. To limit the working pressure in a range of approximately 10 bars and to ensure the effective penetration of the treating liquids, the treating device has several adjacent liquid supply channels that extend perpendicularly to the support and are enlarged on the lower side of the device facing the hide, covering a large area. Between the lower side of the treating device and the hide is arranged a fine-meshed cover and the space between support, hide, cover and treating device can be essentially sealed in relation to the outside.

Description

The invention relates to a device for treating hides with liquids in the so-called wet processes, for example liming, pickling, tanning, dyeing or the like, consisting of a liquid-permeable base which absorbs the skin relentlessly and a treatment device which can be placed essentially tightly on the top of the skin , by means of which the treatment liquid is penetrated into the skin under high pressure.

In leather processing, those wet treatment processes are those treatment stages in which the skin is treated with dissolved chemicals with a high fluid requirement.

These include softening the skin, liming in a strongly alkaline solution, decalcifying (neutralizing) in acid solution, pickling, e.g. by means of proteolytic enzymes, pimples by means of acids and salts, tanning, e.g. using chromium III salts, retanning and greasing the skin and dyeing. The majority of these wet processes take place in conventional tanneries in barrel-like containers with multiple circulation and with different exposure times. Large quantities of liquid are required and constantly circulated.

These tannery wet processes are technically unsatisfactory for several reasons. The skin has to go through a large number of process stages, some of which are carried out in batches with up to 20 tons of skin weight, some of which are processed individually. This requires multiple dissolving of the batches, separating and orienting the skins, for example aligning them according to the head and shield, which is correspondingly time-consuming and labor-intensive. Large skins can have an area of up to 6 m ² and weigh up to 100 kg depending on the water content. Since the transport in large areas of the tannery has to be carried out by hand, a correspondingly large number of workers are required. Due to the aggressive chemicals and the organic substance derived from the skin, it is difficult to create hygienic working conditions for the staff. In addition, there is above all the problem of removing large amounts of waste water, especially since the treatment liquids used can only be reused to a very limited extent.

Dyeing processes could already be improved somewhat (DE-PS 822 060) in that the skins lie on a belt and are guided past a paint spraying device, which at least reduced the difficulties in manipulating the skin. Here too, however, the need for coloring liquid is considerable, since it is sprayed onto the skin at a distance, a large amount of coloring liquid does not come into contact with the skin and, furthermore, a considerable exposure time must be provided in order to penetrate the coloring liquid into the skin to enable. Coloring through is not possible in this way or only with great expenditure of time. In the other aforementioned wet processes, the treatment liquid must penetrate the skin intensively and completely, which is why it must be in constant contact with the treatment liquid over a long period of time. In order to enable targeted working with the lowest possible fluid requirement even in these wet processes, it has been proposed (EP-OS 0 009 081) to introduce the treatment fluid into the skin under high pressure in a kind of inoculation process.

With this vaccination process, it is possible to work with highly concentrated treatment liquids, so that the water requirement is significantly lower than in conventional tanning processes. In this case, only a comparatively small excess of treatment liquid has to be used, which merely has to ensure that the skin is penetrated in its entirety by the treatment liquid. To carry out this method, injection nozzles similar to inoculation guns are used, which are placed on the skin and by means of which the treatment liquid is pressed into the skin under high pressure of more than 50 bar. The treatment liquid then spreads over a somewhat larger area and approximately in a circle in the skin itself. A large number of such injection nozzles are necessary to treat a skin in this way. Years of experiments with this method have not led to satisfactory results. The causes are many. It is difficult to inject the treatment liquid into the skin in a uniform distribution over the entire skin area and the skin cross-section. As a result, areas of inadequate tanning are formed in addition to tanned areas. The different thickness of a skin also leads to problems. The pressure of the treatment liquid must be applied to the thickest areas of the skin, e.g. in the neck and back area. This results in thin areas of skin, e.g. the flames, causing the treatment liquid to be shot through the skin and thus not being able to develop its effect. Finally, the high pressures, particularly in the area where the injection nozzles are attached, can damage the skin. With this method, it is therefore only possible to scrap to some extent without scrap from the meat side of the skin at all. For the rest, the skin must also be left here for a while in order to allow the radiation-injected treatment liquid to penetrate to the side. This lateral penetration then also varies greatly depending on the thickness of the skin.

Finally, with justifiable equipment and costs, it is not possible to treat a complete skin in one work cycle; rather, in the device mentioned at the beginning (EP-OS 0 009 081), the skin is cyclically guided past two row of nozzles arranged one behind the other and offset against one another, so that it is therefore only treated in sections. The vaccine pressure is unrelenting edition recorded by pressing the skin against the inoculation nozzles by means of this edition.

The invention has for its object to improve the aforementioned and aforementioned device in such a way that a uniform penetration of the treatment fluids into the skin is ensured at reduced working pressure.

This object is achieved in that the treatment device has a plurality of liquid supply channels arranged approximately perpendicular to the base, which expand over a large area on the underside of the device facing the skin and are arranged to fill the area, and that between the underside of the device and the Skin arranged a net-like pad and the space between the pad, skin, pad and treatment device is essentially sealed off from the outside.

In the device according to the invention, the feed channels have a comparatively large-area expansion of, for example, several cm ² in the region of their mouth, these extensions having such a geometric outline and such an arrangement that they connect closely to one another, that is to say they cover a large area overall. In order to inject the treatment liquid through the supply channels into the extensions evenly over the cross-section of the extension into the skin, the mesh-like support is provided on the skin, which on the one hand levels the skin somewhat in this area, and on the other hand for a punctual penetration of the treatment liquid over a larger one Cross section ensures. In order to avoid pressure reduction to the outside, the space between the base, the skin, the support and the treatment device can be sealed off from the outside. This is usually possible in that the parts are moved together in a correspondingly tight manner without the need for separate edge seals.

Practical tests with the aforementioned device have shown a number of advantages. It is thus initially possible to work with significantly lower pressures than has been proposed in the prior art. Adequate and extensive penetration is achieved at a pressure in the range of 10 bar. Damage to the skin is completely avoided as a result of this and the large-scale action. It is also possible, depending on the type of wet process, to introduce the treatment liquids from the meat or the grain side. Furthermore, the treatment device can be formed over a large area, so that a complete skin can be treated in a single operation, so that the exposure time and the total treatment time can be reduced considerably. Due to the large-scale action of the treatment liquid and the lower working pressure, it is ensured that the treatment liquid penetrates effectively regardless of the skin thickness and is distributed in the skin. "Bullets" cannot occur, particularly in thin skin areas. This is also favored by the fact that, in contrast to high-pressure inoculation nozzles, the low pressure of approximately 10 bar in the extensions and thus on the skin can be maintained for a long time.

The large-area extensions of the feed channels on the underside of the treatment device can have a polygonal or round outline, at the center of which at least one feed channel opens. The extensions can, for example, have an outline in the form of equilateral triangles, squares, polygons or circles.

As is known per se, a likewise mesh-like intermediate layer can also be arranged between the skin and the base in the device according to the invention, in order to allow the treatment liquids which penetrate the skin to run off. Since such an intermediate layer would, however, be too flexible to absorb the treatment pressure present on the other side, an unyielding underlay must also be provided, which then has a plurality of processes arranged next to one another for the treatment liquid penetrating the skin. The excess treatment liquid penetrating the skin thus penetrates through the fine-meshed intermediate layer to the unyielding base, where it is carried away by the processes.

In a preferred embodiment of the invention, the mesh-like support and intermediate layer consists of a fine-mesh plastic or metal mesh, which on the one hand has the necessary flexibility to adapt to unevenness in the skin, and on the other hand has the necessary resistance to the working pressure without the mesh size changing under the influence of the working pressure . Although it is known (DE-PS 822 060) to use metal nets as a base for skins in order to allow treatment liquid to run off (dyeing liquid), it is also known to also remove such metal nets when de-skinning (squeezing water) use. In the context of the invention, however, the metal mesh fulfills another task, namely to form a support for the skin, which distributes the treatment liquid supplied from the outside uniformly and allows it to penetrate into the skin at points.

According to a further exemplary embodiment, the underside of the treatment device or the extensions arranged there to fill the area can have an extent corresponding to the width or length of the skin, at least in one direction of extension. In this case, the treatment liquids are introduced into the skin in strips, which in turn is then moved batchwise through the device.

In a preferred embodiment, however, is vorese hen that the underside of the treatment device or the extensions of the feed channels arranged there to fill a surface cover a surface which corresponds approximately to the surface of a skin. With this embodiment, it is possible to treat an entire skin in a single operation, so that a high throughput can be achieved.

According to another embodiment, the skin between the support and the intermediate layer are designed as conveyor belts. The skin can therefore be placed between the two conveyor belts and transported between them into the device, so that the manual tasks required for the entire treatment are limited to the task of the skin at the inlet of the conveyor belts and the removal of the skin at the outlet of the conveyor belts. If necessary, the skin can also be thrown off at the conveyor belt outlet.

In a further embodiment of the invention, the base is designed as a table and can be raised against the treatment device. In this case, the skin is introduced between the support and the treatment device by means of the metal nets designed as conveyor belts, then the table is raised against the treatment device with simultaneous pressing of the intermediate layer, skin and support against the treatment device and with a tight seal to the outside, whereupon the treatment liquid is passed over the feed channels can be fed.

Another embodiment is characterized in accordance with the invention in that the base is designed as a circumferential link belt, between the links of which the treatment liquid can run off. In this case, the link belt forms a sufficiently rigid support for the skin, which is also transported here between a fine-meshed intermediate layer and a support.

In this embodiment, the link belt can be trough-shaped in the area of the treatment device and the underside of the treatment device can be curved to fill the trough. In this embodiment, the skin between the support and the intermediate layer is conveyed into the trough between the treatment device and the link belt and can in turn be treated batchwise, but advantageously also in a continuous flow.

In the case of continuous treatment, however, it is expedient if the treatment device is designed as a rotating cylinder, on the circumference of which the extensions of the feed channels are arranged, the feed channels being controllable into their open position only in the region of the trough. In this embodiment with a treatment device running with the link belt, there is therefore no relative movement between the skin and the treatment device, that is to say that despite the continuous passage, it is ensured that the extensions on the underside of the treatment device always remain in the same position relative to the skin, so that the exposure time of the treatment liquid can only be controlled by the transport speed through the trough gap. In this way, skin to skin can be moved through the treatment device.

In a further embodiment of the invention, the fine-meshed support and intermediate layer outside the treatment device is at least one cleaning device, e.g. a spray device is assigned, by means of which impurities, which stuck between the meshes and originate from the skin, can be removed. The spray device can be operated with pressurized water or compressed air. In this way it is ensured that, above all, the fine-meshed support has free mesh cross-sections before each entry into the device, in order to enable the treatment fluids to be distributed correctly.

The device according to the invention is further characterized by a collecting container which holds the excess treatment liquid penetrating the skin and from which the liquid can be recirculated.

Since the device according to the invention makes it possible to work with highly concentrated treatment liquids and these treatment liquids do not or only minimally change their composition during the treatment, the excess of the treatment liquid can be reused. If necessary, a purely mechanical preparation, e.g. filtering out the treatment liquid so that it can be fed back to the treatment device. Only the losses caused by penetration into the skin can be compensated for in terms of quantity. Waste water does not occur in large quantities, at least, since only treatment liquid that can no longer be used for chemical and / or physical reasons must be removed. These are extremely small quantities with well-known ingredients that are easy to control in waste disposal.

In a further advantageous embodiment it is provided that the treatment device is assigned a large-volume pressure container for the treatment liquids, which is provided on the one hand with the collecting container and on the other hand with a feed line for fresh treatment liquid. By means of the pressure vessel, e.g. a wind boiler, the same pressure can be easily maintained for all feed channels. The pressure container is fed on the one hand from the collecting container with the recirculated treatment liquid, and on the other hand with fresh treatment liquid to compensate for the liquid remaining in the skin and any liquid otherwise lost. Instead, the treatment device can also be fed directly with pumps.

Finally, it is useful if in the up Catch container or chemical-physical sensors are arranged in the pressure container, by means of which the feed line for fresh treatment liquid can be controlled to maintain predetermined concentrations in the pressure container. In this way, a completely automated sequence of wet processes in the tannery can be achieved.

• Figur 1 Eine schematische Ansicht einer ersten Ausführungsform der Vorrichtung;
• Figur 2 eine abgebrochene vergrößerte Teilansicht der Behandlungseinrichtung und der Unterlage;
• Figur 3 a bis d eine Ansicht verschiedener Ausführungsformen der Erweiterungen der Zuführkanäle und ihrer Anordnung untereinander;
• Figur 4 eine schematische Ansicht einer zweiten Ausführungsform der Vorrichtung und
• Figur 5 ein schematisches Fließbild einer Versorgungseinrichtung für die Behandlungseinrichtung.

The invention is described below with reference to several exemplary embodiments shown in the drawing. In the drawing show:

• Figure 1 is a schematic view of a first embodiment of the device;
• Figure 2 is a broken enlarged partial view of the treatment device and the pad;
• Figure 3 a to d is a view of different embodiments of the extensions of the feed channels and their arrangement with each other;
• Figure 4 is a schematic view of a second embodiment of the device and
• Figure 5 is a schematic flow diagram of a supply device for the treatment device.

The device in the embodiment according to FIG. 1 has, as essential components, a base 1 and a treatment device 2 arranged above it, the base 1 being designed as a kind of table 3 in a rigid and unyielding construction. The top of the table 3 has several outlets 4 for the treatment liquid.

The treatment device 2 consists of a pressure-resistant housing 5 with a central feed channel 6 and a plurality of feed channels 7 connected to it, which run approximately perpendicular to the surface of the table 3 and are arranged in parallel rows next to one another and one behind the other. They are connected to the central feed line 6 via a distribution line 8. This is provided with a valve 9 to shut off the entire treatment device 2. Furthermore, each individual feed channel 7 has a schematically indicated shut-off valve 10.

The feed channels 7 open out into expansions 11 which are large in relation to the channel cross section and which are openly arranged on the underside 12 of the treatment device 2.

As can be seen in particular from FIG. 2, the valves 10 in the feed channels 7 can be designed differently, for example mechanically operated piston valves 13, as shown in the middle version, or electromagnetic valves, as indicated on the right. Instead of the valves 10, each feed channel 7 can also have only one orifice 13 ', in which case only the central shut-off valve 9 in the central feed line 6 provides for switching on and off.

In the middle opening, the piston valve 13 has a plunger 13 ″ on an extension, which serves to cover part of the support 27 described later, if there is, for example, no skin underneath, on the one hand to prevent the pressure from decreasing too quickly at this point and on the other keep fluid consumption as low as possible.

As can also be seen from FIG. 2, the processes 4 on the top of the table-like base 3 can be directed to a central one. Drain channel 14 may be connected.

In the exemplary embodiment shown in FIGS. 1 and 2, an endless upper belt 15 and also an endless lower belt 16 run between the table-like base 1 and the treatment device 2, between which the skin is applied at 17. Upper belt and lower belt are guided over several deflection rollers and at least one drive roller each. At least the upper band 15 consists of a fine-meshed metal mesh and serves as a support for the skin in the area of the treatment device 2. The lower band 16 can also be a fine-mesh metal net, but possibly also another permeable band.

The skin given up at 17 is retracted between the upper band 15 and lower band 16 between the table-like base 1 and the treatment device 2 and brought into position by stopping the bands. The design is such that the upper belt 15 is located directly below the underside 12 of the treatment device 2 and, as it were, the extensions 11 of the feed channels 7 are limited at the bottom. Subsequently, the gap between the base 1 and the treatment device 2 is closed and sealed to the outside, in that in this embodiment the base 1 can be displaced in the direction of the arrow 18, for example by means of a pressure cylinder, and against the lower belt 16 serving as an intermediate layer in the area of the treatment device skin lying thereon and the upper band 15 forming the support act in such a way that they are pressed tightly against the treatment device 2. The treatment liquid is then fed in via the central feed channel 6 or the valves 10 are opened. After sufficient exposure time, during which the excess and skin-penetrating treatment liquid is drained off via the outlets 4 and the channel 14 (FIG. 2), the table-like support 1 is lowered, the belts 15, 16 are transported at least one skin length further and at the same time the next one Skin inserted into the device.

Behind the treatment device 2, the upper and lower belts 15, 16 pass through a pinch gap formed by two rollers 19, 20, in which the excess treatment liquid which causes the skin to swell is squeezed out. Finally, the upper belt 15 and the lower belt 16 each pass a spray device 21, by means of which any impurities are removed from the meshes of the belts.

The accumulated on the table-like base 1 and discharged via the collecting channel 14 Shot treatment liquid and the treatment liquid squeezed out between the squeeze rollers 19, 20 enter a collecting container 22, which in the exemplary embodiment according to FIG. 1 is designed in the form of a trough. The trough can be equipped with chemical-physical sensors 23, for example p "knives, in order to determine the chemical-physical data of the excess treatment liquid and the degree of its reusability. Furthermore, the trough-shaped collecting container 22 can be equipped with a device 24 for maintaining a certain temperature of the The excess treatment liquid can be recirculated via an outlet 25.

From Figure 2 it can be seen that the skin 26 lying between the support 27 (upper belt 15) and the intermediate layer 28 (lower belt 16), both of which can be in the form of fine-meshed metal nets, after moving the table 3 against the treatment device 2 between them is clamped. Sealing to the outside can take place via the respective outer warp or weft wires of the metal net. The individual extensions 11 are sealed from one another by the fact that between the extensions there are small-area webs 29 which, in the operating position according to FIG. 2, likewise press against the support 27 and thus prevent the transfer of the treatment liquid from one extension 11 into the adjacent one, at least however largely prevent.

The extensions 11 are arranged on the underside 12 of the treatment device 2 (FIG. 1) to fill the entire area. Various embodiments and arrangements are shown in FIG. In the exemplary embodiment according to FIG. 3 a), the extensions 11 have an outline in the form of equilateral triangles, in the center of which the feed channels 7 open out. Figure 3 b) shows extensions 11 with a square outline and again centrally opening feed channels 7, while Figure 3 c) shows extensions 11 with a circular outline and feed channels 7 ending in their center. Finally, the extensions 11 in the embodiment according to FIG. 3 d) are designed as polygons, specifically in the form of regular hexagons. Instead of only one feed channel 7, a plurality of channels can of course open at each extension 11, with a symmetrical arrangement with respect to the outline of the extension being favorable.

In Figure 4, the device is shown in another embodiment. Here, the pad 1 consists of a link belt 30 which is guided over deflection rollers so that its upper run 31 can be deformed into a trough shape. The individual links of the link belt 30 have drain gaps between them through which the excess treatment liquid can drain.

The treatment device 2 is arranged above the link belt 30 in the form of a circular cylinder 32, which is provided over its entire circumference with extensions 11 of feed channels, not shown. The treatment liquid can be fed into the cylinder 32 via a central feed line and can be supplied to the extensions 11 via corresponding radial feed channels. The feed channels each have a shut-off valve which can be opened and closed by means of an actuating element 33. can. For this purpose, a control cam 34 is provided, which is located only on the track section of the rotatable cylinder 32, which coincides with the link belt 30. The treatment of the skin takes place in this path section, in which the upper run 31 of the link belt 30 is deflected in a trough-shaped manner.

Here too, a support formed by an upper belt 33 is provided, as is also a lower belt 34. The skin is applied between the upper band 33 and lower band 34 at 35 and transported into the gap between the treatment device 2 and the link belt 30. By synchronous circulation of the treatment device 2 and the link belt 30, it can be ensured that the extensions 11, in which the treatment liquid is under pressure, are always opposite the same point in the house.

FIG. 5 shows part of the supply device for the treatment device in the form of a flow diagram. It has a wind boiler 36 as a storage container for the treatment liquid, which is equipped with a pressure transmitter 37 and a safety valve 38. The level of the treatment liquid is controlled between a maximum level 39 and a minimum level 40 within the wind chamber 36. The wind boiler 36 is connected to the treatment device 2 via a supply line 41 and is also connected to the collecting container 22 via a feed line 42 and to a reservoir 44 which contains fresh treatment liquid via a further feed line 43. Pumps 45 and 46 are inserted into the feed lines 42 and 43. Losses of treatment liquid are compensated for via the feed line 43, as are any concentration fluctuations, while the recirculable treatment liquid is conveyed out of the collecting container 22 via the feed line 42.

Claims (16)

1. Apparatus for treating skins or hides with liquids in so-called wet processes, e.g. liming, drenching, tanning, dyeing or the like, comprising a liquid-permeable substrate inflexibly receiving the hide and a treatment device substantially tightly applicable to the top of the hide by means of which the treatment liquid penetrates the skin under high pressure, characterized in that the treatment device (2) has several liquid supply ducts (7) arranged approximately perpendicular to the substrate (1) and which on the underside (12) of the device (2) facing the hide (26) are widened in large-area manner and are arranged in surface-filling manner thereon and that between the underside (12) of the device (2) and the hide (26) is provided a net-like support (27) and the gap between the substrate (1), hide (26), support (27) and treatment device (2) is substantially tightly sealable with respect to the outside.

2. Apparatus according to claim 1, characterized in that the large-area widened portions (11) of supply ducts (7) have on the underside (12) of treatment device (2) a polygonal or circular contour, into whose centre issues at least one supply duct (7).

3. Apparatus according to claim 2, characterized in that the widened portions (11) have a contour in the form of an equilateral triangle, square, circle or polygon.

4. Apparatus according to one of the claims 1 to 3, characterized in that between hide (26) and substrate (1) is provided a net-like intermediate layer (28) and the substrate (1) is provided with several juxtaposed drains (4) for the treatment liquid penetrating hide (26).

5. Apparatus according to one of the claims 1 to 4, characterized in that the support (27) and intermediate layer (28) are formed by a preferably fine-mesh plastic or metal net.

6. Apparatus according to one of the claims 1 to 5, characterized in that the underside (12) of the treatment device (2) or the widened portions (11) of supply ducts (7) arranged there in surface-filling manner have, in at least one extension direction, an extension corresponding to the width or length of the hide (26).

7. Apparatus according to one of the claims 1 to 6, characterized in that the underside (12) of the treatment device (2) or the widened portions (11) of the supply ducts arranged there in surface-filling manner cover a surface area roughly corresponding to the surface of a hide (26).

8. Apparatus according to one of the claims 1 to 7, characterized in that the support (27) and intermediate layer (28) receiving the hide (26) between them are constructed as conveyor belts (15, 16).

9. Apparatus according to one of the claims 1 to 8, characterized in that the substrate (1) is constructed as a table (3) and can be raised against the treatment device (2).

10. Apparatus according to one of the claims 1 to 9, characterized in that the substrate (1) is constructed as a revolving link belt (30), between whose links the treatment liquid can drain away.

11. Apparatus according to claim 10, characterized in that the link belt (30) is guided in trough-like manner in the vicinity of the treatment device (2) and the underside (12) of treatment device (2) is curved so as to fill the trough.

12. Apparatus according to claims 10 or 11, characterized in that the treatment device (2) is constructed as a revolving cylinder (32), on whose circumference are arranged the widened portions (11) of supply ducts (7) and that the supply ducts (7) are only controllable in the vicinity of the trough in the opening position.

13. Apparatus according to one of the claims 1 to 12, characterized in that with the fine-mesh support (27) and intermediate layer (28) a cleaning device (21), e.g. a spraying device is associated outside the treatment device (2).

14. Apparatus according to one of the claims 1 to 13, characterized by a collecting container (22) which receives the excess treatment liquid which has penetrated the skin (26) and from which the liquid can be recirculated.

15. Apparatus according to claim 14, characterized in that with the treatment device (2) is associated a large volume pressure vessel (36) for the treatment liquid, which is on the one hand provided with the collecting container (22) and on the other with a feed-line (43) for the fresh treatment liquid.

16. Apparatus according to one of the claims 1 to 15, characterized in that chemical-physical sensors (23) are arranged in the collecting container (22) or in the pressure vessel (36) and by means thereof the feed line (43) for the fresh treatment liquid can be controlled for maintaining predetermined concentrations and quantities in the pressure vessel (36).

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