WO1991004343A1

WO1991004343A1 - Device for the wet-treatment of hides

Info

Publication number: WO1991004343A1
Application number: PCT/EP1990/001440
Authority: WO
Inventors: Arne Petersen
Original assignee: Johs. Krause Gmbh
Priority date: 1989-09-14
Filing date: 1990-08-30
Publication date: 1991-04-04
Also published as: DE3930767A1; AU629395B2; AU6270890A; KR920701485A; EP0442989A1; RU1838425C; JPH04501880A; NZ235188A

Abstract

Described is a device for the so-called wet-treatment of animal hides with liquids, comprising a lower conveyor belt carrying the hides, an upper conveyor belt covering the hides, both conveyor belts being permeable to liquids, a rigid work bench over which the conveyor belts with hides lying between them pass, and, located over the work bench, a treatment device with at least two rows of nozzles which are staggered wih respect to each other, which extend at least over the whole width of the working area and which spray treatment liquids under pressure so that they penetrate into the hides. To increase the work rate, it is proposed that the conveyor belts are driven continuously and the nozzles are mounted a very small distance above the hides or upper conveyor belt and driven to oscillate at right angles to the direction of motion of the hides.

Description

Device for treating hides in wet processes

The invention relates to a device for treating hides with liquids in the so-called wet processes, for. B. liming, pickling, tanning, dyeing or the like, consisting of a skin-absorbing lower conveyor belt, an upper skin-covering conveyor belt, both of which are liquid-permeable, a rigid work table, over which the conveyor belts with the one between them Skin are guided and a treatment device arranged above with at least two rows of nozzles with offset nozzles, which extend at least over the working width and by means of which the treatment liquids are penetrated into the skin under pressure.

In leather processing, the wet 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, descaling (neutralizing) in acidic solution, pickling, e.g. B. using proteolytic enzymes, pimples using acids and salts, tanning, z. B. by means of chro-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 frequent circulation and with different exposure times. Large quantities of liquid are required and continuously 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, e.g. B. alignment according to head and shield, which is correspondingly time and labor consuming. Large skins can have an area of up to 6 m2 and weigh up to 100 kg depending on the water content. Since the transport is to be carried out by hand in large areas of the tanner's operation, a correspondingly large number of workers are necessary. Due to the aggressive chemicals and the organic substance derived from the skin, it is hardly possible 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 have already been 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 reduces 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, with a large amount of Coloring liquid does not come into contact with the skin and a considerable exposure time must also be provided in order to allow the coloring liquid to penetrate into the skin. 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.

In this inoculation process it is possible to work with highly concentrated treatment liquids, so that the water requirement is considerably 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 therefore difficult to introduce the treatment liquid into the skin in a uniform distribution over the entire skin area and the skin cross-section. Make it up consequently, in addition to areas that have been tanned through, areas of inadequate tanning. The different thickness of a skin also leads to problems. The pressure level of the treatment liquid must be applied to the thickest areas of the skin, e.g. B. in the neck and back area. This results in thin areas of skin, e.g. B. the Flemish, that the treatment liquid is shot through the skin and thus can not develop its effect. Finally, the high pressures, especially in the area where the injection nozzles are attached, can damage the skin. With this method, it is therefore possible to process to a certain extent only free of waste from the meat side of the skin at all. For the rest, the skin must also be left here for some time in order to allow the radiation-injected treatment liquid to penetrate to the side. This lateral penetration also varies greatly depending on the thickness of the skin.

Finally, with justifiable expenditure in terms of 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 applied to two rows of nozzles arranged one behind the other and offset against one another passed in cycles, so that it is therefore only treated in sections. The inoculation pressure is taken up by the unyielding pad by pressing the skin against the inoculating nozzles by means of this pad.

Devices which operate in cycles are also known (US Pat. No. 1,363,771 = DE-PS 328 884, SU Pat. No. 737 463, WO-OS 88/05828) in which the skin is between an upper nozzle plate and a lower plate Drain channels is clamped. These devices work at a lower pressure and are therefore gentler on the skin. Here too the machine output is limited due to the discontinuous mode of operation. Furthermore, due to the punctual action of the treatment liquids, a longer dwell time between the plates must be observed.

The object of the invention is to enable faster treatment of the skins without impairing the penetration of the treatment liquids into the skin.

Starting from the known device mentioned at the beginning (WO-OS 88/05828), this object is achieved in that the conveyor belts are driven continuously and the rows of nozzles are arranged at a very short distance above the skin or the upper conveyor belt and driven oscillating transversely to the direction of transport are.

In contrast to the devices working with these plates, but with two conveying changes that enclose the skin between them (WO-OS 88/05828, SU-PS ~ 7 463), the device according to the invention has at least two rows of nozzles arranged at a very short distance above the skin or the upper conveyor belt, which makes it possible to drive the conveyor belts continuously, that is to say to move the skin continuously under the rows of nozzles. A relatively low transport speed is maintained. The small distance naturally results in a pressure loss when spraying on the treatment liquids compared to the direct nozzle cross section. In order to keep this as small as possible, the distance <. 3 mm, preferably in the range of 1 mm. In order to allow the treatment fluids to penetrate properly despite the pressure loss, the rows of nozzles are moved in an oscillating manner transversely to the transport direction. Because of this oscillation Due to the jet pressure, the flesh side of the skin is constantly loosened and the fibers are kept in motion due to the movement and the very small distance of the nozzle rows from the skin, so that the treatment liquids can penetrate freely over the entire surface and into the depth.

A preferred embodiment is characterized in that the work table is designed as a lifting table for adjusting the distance between the rows of nozzles and the skin.

While the treatment device with the rows of nozzles is arranged in a fixed position, the work table can be raised and lowered. In this way, the distance between the rows of nozzles and the skin can be adjusted very precisely by means of the lifting table to match the skin thickness.

The treatment device advantageously consists of a container to which the treatment liquids are fed under pressure and the rows of nozzles connected to the container. The excess treatment liquid, which, as already known, is collected in a trough, is recirculated, first passing through filters in order to retain solids from the treatment liquid and to avoid clogging of the nozzles.

The rows of nozzles are advantageously formed on at least two, preferably on a plurality of nozzle pipes which extend approximately in the transport direction and are arranged approximately over the working width. As a result, the treatment liquid is applied simultaneously over the entire working width and over a certain transport length. It is preferably provided that the nozzle tubes at a small angle, for. B. 10 degrees, are arranged opposite the transport direction.

By a slight inclination of the nozzle pipes in relation to the transport direction, an offset of the nozzles in this direction is achieved at the same time, so that it is ensured that the skin is intensively treated with the liquid over the entire working width, but at the same time it is avoided that the liquid in parallel strips is applied.

An advantageous embodiment is characterized in that the container with the nozzle tubes is fastened to a crossbar which is arranged above the work table and which is in turn suspended transversely, the crossbar being driven to oscillate.

With regard to the oscillation movement, it is advantageous if it can be carried out with a variable frequency and / or amplitude in order to enable adaptation to different skin qualities.

The lifting table can on opposite sides by means of synchronously driven actuators, for. B. threaded spindles, and these can over a looping endless drive, z. B. a chain drive. This guarantees a synchronous drive of the threaded spindles and thus a uniform lifting of the entire lifting table, parallel to the nozzle tubes.

The actuators can be driven by hand. However, it can instead be provided that the lifting table is driven continuously and can be controlled by means of a device which scans the thickness of the skin. This embodiment has the advantage that there is always the optimal distance between the rows of nozzles and the skin. This is particularly advantageous for changing skin qualities.

The rows of nozzles are expediently arranged parallel to one another at a small distance, for example in the direction of transport, in order to ensure the uniform treatment of a skin strip over the entire working width.

In a further expedient embodiment it is provided that the nozzle tubes are bent in a U-shape and are connected to the container by means of their legs, while the U-web, which extends approximately in the transport direction, has the nozzles. This embodiment is characterized by its particularly simple and therefore inexpensive construction.

It can also be provided that the crossmember by means of a controllable drive, for. B. a RegeIgearmotor and an eccentric is driven to oscillate in order to vary the frequency of the oscillation movement.

Practical tests have shown that perfect penetration of the treatment fluids is ensured if the amplitude of the oscillation movement is 10 mm and the distance of the nozzle rows from the skin or the conveyor belt is <_ 3 mm, preferably _ <2 mm.

The invention is described below using an exemplary embodiment shown in the drawing. The drawing shows:

Figure 1 is a schematic side view of the device; FIG. 2 shows a schematic view of the treatment device with work table;

Figure 3 is a view of the underside of the treatment device with the nozzle tubes;

Figure 4 is a view of the device in

Direction of transport and

FIG. 5 shows a top view of the device in the illustration according to FIG. 4.

In Figure 1, the essential parts of the device and the associated system parts can be seen. A treatment device 2 is shown above a work table 1, to which the treatment liquids are supplied under pressure. Between the work table 1 and the treatment device 2, a lower conveyor belt 3 and an upper conveyor belt 4 run through, each of which is permeable to liquids, e.g. B. are in the form of a fabric or mesh tape, and between them take up the skins, which are placed at 5. The lower conveyor belt 3 rotates in the direction of the arrow 6 and is driven continuously, if appropriate like the upper conveyor belt 4. A squeezing mechanism 7 is arranged near the discharge end of the lower conveyor belt 3, between the rollers of which the conveyor belt 3 with the skin lying thereon is passed in order to press off the excess treatment liquid located in the skin. At the output of the upper conveyor belt 4, a brush roller 8 is arranged, which cleans the upper conveyor belt 4 from dirt in order to Always ensure passage of the treatment liquid from the treatment device 2.

Arranged underneath the conveyor belt 3 is a collecting trough 9 which collects the excess treatment liquid. The treatment liquid is sucked out of the tub 9 by means of a pump 11 via a sump filter 10 and optionally fed to the treatment device 2 via filters 12 connected in parallel. A cooler 13 is also arranged in the collecting trough, which in turn is assigned a cooling circuit, designated overall by 14.

Furthermore, storage containers 15 can be seen in FIG. 1, which contain different treatment liquids (liquors). The respective desired liquor can be supplied from these storage containers 15 to the collecting trough 9 via the pump 16 and from there to the treatment device 2 via the pump 11. There are also two other smaller storage containers

17 shown, which contain concentrated chemicals that only during the treatment process by means of a pump

18 are supplied. Finally, the drip pan also has a water connection 19 for dilution purposes.

The work table 1 and the treatment device 2 can be seen in more detail in FIG. The skin 20 arranged between the conveyor belts 3 and 4 can also be seen. It is guided by means of the conveyor belts 3, 4 past at least two rows of nozzles 21 of the treatment device 2, it resting on the work table 1 via the lower conveyor belt 3. The distance between the rows of nozzles 21 and the skin is very small and is preferably less than 2 mm. This distance can be formed by forming the work table 1 Adjust the lifting table, which can be raised and lowered in the direction of the double arrow 22.

The row of nozzles 21 is realized on a nozzle tube 23 which has a plurality of downwardly directed nozzles 24 and is bent in a U-shape in the exemplary embodiment shown. The nozzle tube 23 is connected via the U-legs 25 to a container 26 containing the treatment liquid, to which the treatment liquid is supplied under pressure in the manner described with reference to FIG.

A constructive embodiment of the device is shown in FIGS. 3 to 5. FIG. 3 shows a view of the underside of the container 26. In the exemplary embodiment shown, a plurality of nozzle tubes 23 are connected to the container 26, only four of which are shown in FIG. 3 in the outer region of the working width. The Düsen¬ tubes 23 are arranged side by side with a small distance. As can also be seen, the nozzle tubes 23 run at a small angle to the transport direction 6. The container 26 with the nozzle tubes 23 is connected via a coupling 27 to a supply line 28, which is preferably designed as an elastic hose. The container 26 is also attached to a cross member 29, which in turn is suspended from rods 30 in the bearings 31 and 32. The crossmember 29 also has on one side a bearing eye 33 on which a push or crank rod 34 engages, which is driven by a gear motor 35 via an eccentric 36, with the result that the crossmember and therewith the container 26 with the rows of nozzles 23 carries out an oscillating movement transversely to the transport direction 6. The frequency of the oscillation movement can be adjusted by means of the control gear motor 35. Due to the oscillation movement, the nozzle tubes 23 describe how in particular can be deduced from FIG. 3, a back and forth movement above the skin with the result that the skin is coated over the entire working width and over a certain distance in the direction of transport 6. The nozzles 24 in the nozzle tubes 23 are offset from one another. The work table 1 designed as a lifting table is guided via lateral supports 37 on threaded spindles 38, which are driven together by a chain 39 via chain wheels 40. In the exemplary embodiment shown, the drive takes place by means of a hand wheel 41, which acts on one of the chain wheels 40.

Claims

1. Device for treating hides with liquids in the so-called wet processes, for. B. liming, pickling, tanning, dyeing or the like, consisting of a skin-absorbing lower conveyor belt, an upper skin-covering upper conveyor belt, both of which are liquid-permeable, a rigid work table over which the conveyor belts with the between skin lying on them and a treatment device arranged above them with at least two rows of nozzles with offset nozzles which extend at least over the working width and by means of which the treatment liquids are penetrated into the skin under pressure, characterized in that the conveyor belts (3, 4) continuously driven and the rows of nozzles (21) are arranged at a very short distance above the skin (20) or the upper conveyor belt (4) and are driven oscillating transversely to the direction of transport.

2. Device according to claim 1, characterized in that the work table (1) for adjusting the distance between the rows of nozzles (21) and the skin (20) is designed as a lifting table.

3. Apparatus according to claim 1 or 2, characterized gekennzeich¬ net that the treatment device (2) consists of a Be¬ container (26) to which the treatment liquids are supplied under pressure, and the nozzle rows connected to the container (21) .

4. Device according to one of claims 1 to 3, characterized in that the rows of nozzles (21) on at least two approximately in the transport direction (6) extending nozzle tubes (23) are formed.

5. Device according to one of claims 1 to 4, characterized in that the nozzle rows (21) at a Mehr¬ number of approximately extending in the transport direction and arranged approximately over the working width nozzle tubes

(23) are formed.

6. Device according to one of claims 1 to 5, characterized in that the nozzle tubes (23) are arranged inclined at a small angle with respect to the transport direction (6).

7. Device according to one of claims 1 to 6, characterized in that the angle is £ 10 degrees.

8. Device according to one of claims 1 to 7, characterized in that the container (26) with the Düsen¬ tubes (23) on a above the work table (1) angeord¬ Neten traverse (29) is attached, which in turn quer¬ is flexibly suspended.

9. Device according to one of claims 1 to 8, characterized in that the crossmember (29) is driven to oscillate.

10. Device according to one of claims 1 to 9, characterized in that the frequency and / or the amplitude of the oscillation movement is variable.

11. Device according to one of claims 1 to 10, characterized in that the lifting table (1) is driven on opposite sides by means of synchronously driven actuators (38).

12. Device according to one of claims 1 to 11, characterized in that the lifting table (1) by means of threaded spindles (38) and this via an endless drive looping around them (39), for. B. a chain drive are driven.

13. Device according to one of claims 1 to 12, characterized in that the lifting table (1) is adjustable by hand.

14. Device according to one of claims 1 to 12, characterized in that the lifting table (1) is driven continuously and is controllable by means of a device sensing the thickness of the skin (20).

15. The device according to one of claims 1 to 14, characterized in that the nozzle tubes (23) are arranged parallel to each other at a short distance approximately in the transport direction (6).

16. The device according to one of claims 1 to 15, characterized in that the nozzle tubes (23) are U-shaped gene and are connected by means of their legs (25) to the container (26), while the U-web extending approximately in the transport direction has the nozzles (24).

17. The device according to one of claims 1 to 16, characterized in that the crossmember (29) by means of a controllable drive, for. B. a variable speed gear motor (35) and an eccentric (36) is driven to oscillate.

18. Device according to one of claims 1 to 17, characterized in that the amplitude of the oscillation movement is 10 mm.

19. Device according to one of claims 1 to 18, characterized in that the distance of the row of nozzles (21) from the skin (20) or the conveyor belt (4) is 3 mm, preferably <^ 2 mm.