EP0253111B1 - Method and apparatus for continuously treating wet moving tubular fabric - Google Patents

Description

The invention relates to a method for treating continuously transported tubular goods in the wet state, according to the preamble of claim 1. Furthermore, the invention relates to an apparatus for carrying out this method.

A method and an apparatus of the kind described are known from DE-A-34 33 701. In this case, an expansion zone is sealed at its beginning and end by a pair of rollers, one roller of which can be driven and regulated. In order to be able to stretch or overstretch tubular goods depending on their width measured according to the stretch zone in the stretch zone by means of blown-in air, the feed rate and / or the take-off speed of the tubular goods are regulated via the speed of the driven rollers. In contrast to other known embodiments working with mechanical stretching devices, a very uniform stretching of the tubular goods is achieved in the manner described above without the surface being adversely affected (by mechanical devices).

The object of the present invention is to provide a further method of the type required in the preamble of claim 1, which is characterized by a very even stretching and gentle treatment of the tubular goods in that it has a particularly space-saving and structurally simple design for its implementation used device allows.

This object is achieved by the features specified in the characterizing part of claim 1.

Since, in the method according to the invention, the tubular fabric immediately stretches to the last stage of a wet treatment, that is to say the stretch zone with the balloon-like inflation of the tubular fabric is arranged here, there is first of all a considerable saving of space compared to a stretch zone to be arranged separately. This and the structurally relatively simple construction of the associated device are further favored by the fact that the wet tubular goods from the last wet treatment stage are supplied in sufficient quantity to the beginning of the expansion zone, that the stock of goods which is always present there ensures sufficient sealing of the tubular goods against air leakage , whereby the tubular goods can be fed to the beginning of the expansion zone without tension and can also be removed from there without tension and fed to the actual expansion zone.

The desired simplification is supported in an extremely advantageous manner in that the correction value determined in the actual value / setpoint comparison is used as a correction output signal in order to increase the amount of air injection into the tubular fabric in the expansion zone in the sense of a width correction of this tubular fabric found to be necessary Taxes.

In the practical implementation of the method, the stretch zone can thus be provided, for example, immediately after or above a last washing compartment, impregnation compartment or another wet treatment compartment, it also being advantageous to treat the goods in a tube-wide condition and thus at the beginning of the stretch zone feed.

Furthermore, the tubular goods can be passed through a pinch joint at the end of the expansion zone in a manner known per se and be drained and laid flat in the process. As a result, the tubular goods can be dewatered not only continuously through a continuously working wet treatment plant and an expansion zone with stretching width, but also continuously - without stopping the wet treatment plant - in the finished width.

In the case of the last-mentioned procedure in particular, it is furthermore advantageous if chemicals are additionally metered in on all sides of the wet tubular fabric in the area directly in front of the pinch joint. Above all, plasticizers can be applied, but also other chemicals to be applied. This means that the chemical application to the wet tubular goods can be carried out in one operation with the wet over-stretching and dewatering of these tubular goods and with their continuous further transport. In this regard, it should be noted that it was previously believed in the specialist world that a targeted application of chemicals or plasticizers should only be carried out with a difference in moisture, i.e. that the liquor entry into a corresponding application compartment must be less than the liquor discharge, the corresponding amount of application chemicals being contained in this differential moisture. As a result, it was not possible to heavily drain the tubular goods in such known designs. Although in the method according to the invention the majority of the application chemicals are removed again during squeezing, the experiments on which the invention is based have shown that the application of chemicals, in particular plasticizers, just before the pinch joint - compared to the known methods - to significantly better results (higher application yield) leads.

A device for carrying out the method according to the invention contains the features specified in the preamble of claim 3 and is characterized by the features specified in the characterizing part of this claim 3.

Further details and advantages of the invention emerge from the remaining subclaims.

• Fig. 1 eine vereinfachte, schematisierte Seitenansicht von dem Auslaufteil einer Naßbehandlungsanlage mit unmittelbar zugeordneter Dehnungszone;
• Fig. 2 ein stark vereinfachtes Laufschema von Schlauchware im Bereich der Dehnungszone und einer Breiten-Meßeinrichtung, zur Erläuterung der Verfahrensweise der Vorrichtung nach Fig. 1.

The invention is explained in more detail below with reference to the drawing. Show in this drawing

• Figure 1 is a simplified, schematic side view of the outlet part of a wet treatment system with a directly assigned expansion zone.
• Fig. 2 is a greatly simplified flow diagram of tubular goods in the expansion zone and egg ner width measuring device, to explain the procedure of the device according to FIG. 1.

In the embodiment illustrated in FIG. 1, the device for the wet treatment of continuously transported tubular goods 1 is arranged directly on the outlet part of a suitable wet treatment system, of which for the sake of simplicity only the last wet treatment compartment 2 is illustrated, which in the present case is in the form of a boot known per se is formed, but can also be formed in any other suitable manner if necessary.

An expansion zone 3 of the treatment device according to the invention is provided directly above the lower boot end 2a of the wet treatment compartment 2, in which compressed air is injected into the wet tubular fabric with the help of a nozzle device 4 to be explained and this tubular fabric 1 is thereby - as indicated by the air bubble 5 - can be inflated like a balloon and thus overstretched in a targeted manner. In order to be able to maintain the air bubble indicated at 5 in the desired manner, the essentially vertically oriented expansion zone 3 is at the beginning and end, i.e. sealed at the upper and lower ends so that essentially no compressed air blown into the wet tubular fabric 1 can escape to the outside. In general, it should also be mentioned in this connection that a certain proportion of the compressed air blown in can always escape from the air bubble 5 through the goods, depending on the pore size and liquid content, but that the balloon width of the air bubble 5 or the width of the tubular goods, however, when the compressed air supply is regulated can be regulated constantly. The compressed air supply and its control will be discussed in more detail below.

In the exemplary embodiment illustrated in FIG. 1, the lower boot end 2a forming a transition area between the last wet treatment compartment 2 and the stretching zone 3 contains a sliding grid 6, which is preferably designed as a plastic sliding grate, which brings the wet tubular goods 1 free of tension and a goods store immediately below the stretching zone 3 forms, as indicated in Fig. 1 by the tubular fabric 1 pushed together in folds in the lower boot end 2a. This goods store on the sliding grate 6 thereby simultaneously forms a lower sealing point at the lower end of the expansion zone 3 against air leakage from the tubular material 1. At the upper end of the expansion zone 3, on the other hand, the upper sealing point is formed by a pair of squeeze rollers 7 which are known per se. The bladder 5, which is formed within the tubular fabric 1 by the blowing in of compressed air and is constantly maintained, is thus limited at the lower end by the seal on the part of the goods store and at the upper end by the pair of nip rollers 7 in its vertical length extension.

The nozzle device 4 provided for blowing compressed air into the tubular material 1 can in principle be designed and arranged in any suitable embodiment. It is particularly advantageous if - as shown in FIG. 1 - this nozzle device contains two swivel arms 8a and 8b arranged on both sides of the tubular fabric 1, at the free ends of which compressed air nozzles 9 are attached, between which the tubular fabric 1 is guided. Contrary to the compressed air nozzles 9, the swivel arms 8a, 8b containing the supply air lines to the compressed air nozzles 9 are held in only indicated swivel bearings 10a and 10b, so that the swivel arms 8a, 8b can move in the direction of the indicated double arrows 11, which on the one hand makes it easy Guidance of the inflated tubular goods 1 within the expansion zone 3 can be achieved without an undesirable mechanical influence on the outside of the tubular goods 1 (chafing points).

Via the hollow pivot bearings 10a, 10b, the compressed air nozzles 9 are connected to a compressed air supply line 12 in which a continuously regulating compressed air metering valve 13 is provided and which in turn is connected to a high-performance blower 14 belonging to the nozzle device 4. In the present case, the compressed air metering valve 13 is assigned a motor with a control controller 15, the metering valve 13 of the nozzle device 4 being connected in terms of control to a computer 16 of a suitable design via this motor with the control controller 15. A width measuring device 17 is also connected in terms of control to this computer 16, which can be provided in any suitable embodiment. The computer 16 simultaneously connects the width measuring device 17 with the nozzle device 4 or its compressed air metering valve 13 in such a way that the compressed air supply to the nozzle device 4 can be controlled or readjusted as a function of a difference between the measured and predetermined width of the goods.

Any mechanical, electromechanical or electronic device suitable for this purpose can be used as the width measuring device 17. However, it is particularly advantageous if this width measuring device is a photoelectronic measuring device 17 working with a light curtain.

In such a photoelectronic measuring device 17 - as illustrated in FIG. 2 - with the aid of the light curtain indicated by arrows 18, the effective width or actual width of the tubular fabric 1 which has been laid flat again behind the expansion zone 3 (behind its pair of nip rollers 7) can then also be exact be measured when the tubular goods 1, the pair of squeeze rollers 7 are not centric, ie happened laterally offset.

In the example in FIG. 1, the treatment device according to the invention also contains an application spray device 19, directly in front of the pinch joint or the pinch roller pair 7 that forms it, by means of which suitable chemicals, for example plasticizers, can be sprayed onto the wet tube material 1 before the tube material the pinch roller pair 7 pas siert. This application spray device 19 contains two spray tubes 20 arranged on both sides of the tubular goods 1 and a circulation pump 21 which is connected to the spray tubes 20 on the one hand via a pressure line 22 and, on the other hand, via its suction line 23 to a fleet collecting device 24 below the wet treatment compartment 2. An application medium metering device 25 of a suitable design is also connected to the suction line 23 of this circulation pump 21 via a metering line 26.

In the area of the spray tubes 20, i.e. also close to the pair of squeeze rollers 7, two guide rods or guide rollers 27, which are provided at a suitable distance from one another and act on the outside of the inflated tubular fabric 1, can also be provided in such a way that the tubular fabric 1 running towards the squeeze rollers 7 already exists is compressed to a certain extent and aligned in the width in order to enable the pair of nip rollers 7 to pass without wrinkles.

The design and arrangement of the treatment device described so far with reference to the example according to FIG. 1 is extremely space-saving but is simply constructed and easily accessible everywhere. In this exemplary embodiment explained, the device also represents an extremely favorable combination of three essential treatment processes: the main type of treatment, namely the wet stretching and spreading of the wet tubular goods, can be carried out in an extremely advantageous manner with the dewatering of the tubular goods (by means of the upper pair of nip rollers 7) and with the Application of additional chemicals (eg plasticizers or the like) in the area in front of the nip rollers can be combined. These three treatment options can thus be combined in a single, continuous process in a space-saving manner and with simple constructional means.

With regard to the structural design, there are of course still many possible variations with regard to a number of device parts within the scope of the invention. For example, instead of the proposed sliding grating 6 (for feeding the tubular goods 1 and forming the goods store at the lower end of the expansion zone 3), any other suitable device can be used that serves the same purpose, for example a conveyor belt or the like. The assignment of the compressed air nozzles 9 the most suitable longitudinal or vertical section of the expansion zone 3 (for example arrangement of the compressed air nozzles 9 in the upper or lower half of the expansion zone 3) will depend primarily on the type of wet treatment beforehand. Furthermore, a suitable converter can be used for controlling the motor 15 of the compressed air metering valve 13 instead of the positioner mentioned, for example a so-called IP converter, by means of which the electrical or electronic control signals coming from the computer 16 are converted into pneumatic control variables. to control the drive of the compressed air metering valve 13 in the sense of opening, closing or throttling this valve.

The spreading process according to the method according to the invention is again explained below using the running scheme according to FIG. 2.

It is assumed that the tubular fabric 1 is transported continuously at a predetermined speed in the direction of arrow 1a through the expansion zone 3 through the pair of squeeze rollers 7 and finally through the width measuring device 17. The tubular fabric 1 is, for example, circular knitted tubular fabric which is to be specifically stretched or stretched to a predetermined width (in the folded-up state again). For this purpose, the tubular fabric 1, which is sealed at the beginning and end of the expansion zone 3 against air leakage, is overexpanded in the wet state with the aid of the air bubble 5, which is constantly maintained within the tube by compressed air injection (tests have shown that wet tubular fabric with air up to about 30% of its width can be overstretched). In the deliberately overstretched state, the wet tubular fabric 1 passes through the pinch joint formed by the pair of squeeze rollers 7, is retained by the air bubble 5 and the tubular fabric 1 is mechanically dewatered. At the same time, the tubular goods 1 are laid completely wrinkle-free in this pinch joint. The squeezed-out and downward-flowing liquid seals off the goods balloon formed in the expansion zone 3 (ie free spaces between the fibers are closed by the liquid) and thus allows the tubular goods 1 to be overstretched only at the points at which compressed air is supplied via the compressed air nozzles 9 is injected into the interior of the tubular fabric 1, the liquid is displaced by air.

In the broad state, i.e. in its full width WB achieved by overstretching, the tubular fabric 1 then passes through the width measuring device 17. In this width measuring device 17, the actual width achieved or the actual value obtained is measured electronically with the aid of a light curtain indicated by arrows 18. This has the advantage that the effective fabric width WB can also be determined very precisely if - as indicated in FIG. 2 - the tubular fabric 1 does not run quite centrally to the pair of nip rollers 7, i.e. runs offset to one or the other long side (cf. double arrow 28).

The actual value of the fabric width WB measured in the width measuring device 17 is fed to the computer 16, into which a desired value, ie the desired fabric width, is entered. The actual value and the target value are then compared in the computer 16. If a deviation between the actual value and the target value is ascertained in the computer 16, ie if, for example, the actual value is 500 mm and the predetermined target value is 600 mm, then a corresponding correction value is formed, which is converted in the computer into a correction output signal. This correction output signal is sent to a position controller 29 of the motor 15 assigned to the compressed air metering valve 13 or a suitable one Transducers (for example, so-called IP converters) are supplied so that the amount of air injection (via the compressed air nozzles 9) into the tubular fabric 1 can be controlled or readjusted in the sense of the required width correction of this tubular fabric 1. If, for example, the actual value of the fabric widths WB behind the expansion zone 3 is determined to be too small, then the amount of compressed air to be introduced into the tubular fabric 1 via the compressed air nozzles 9 must be increased accordingly in order to bring about a greater overstretching of the tubular fabric 1 in the expansion zone 3, and vice versa.

If plasticizer or another chemical is also to be applied during this overstretching of the wet tubular fabric 1 before dewatering (pinch roller pair 7), this can be done in the manner described above with reference to FIG. 1 with the aid of the application spray device 19. Plasticizers can be used, for example, in the order of about 1-2% of the weight of the goods. These application chemicals are expediently metered into the suction line 23 of the circulation pump 21 (see FIG. 1), so that the resulting liquor with the help of the spray tubes 20 on both sides or on all sides directly in front of the pinch joint (pinch roller pair 7) on the outside of the Tubular goods can be applied.

Claims (9)

1. Method of treatment of continuously moving tubular fabric (1) in the wet state, in which

a) in an expansion zone (3) compressed air is blown into the wet tubular fabric (1) which is sealed against the escape of air at the beginning and end of this zone, and the tubular fabric is deliberately expanded thereby,

b) behind the expansion zone (3) the width (WB) of the tubular fabric is measured, the actual value obtained for the fabric width is compared with a predetermined theoretical value and in the event of differences between the actual value and the theorectical value a correction value is formed,

c) an adjustment is carried out in the region of the expansion zone as a function of the magnitude of the correction value, characterised by the following further features;

d) the expansion of the tubular fabric (1) follows directly after the last stage (2) of a wet treatment, and the wet tubular fabric is delivered from this last wet treatment stage to the expansion zone (3) free of tension and in such a quantity that the beginning of the expansion zone is sealed against the escape of air by the material store;

e) the correction value obtained from the comparison between the actual value and the theoretical value is converted into a correction output signal which controls the quantity of air blown into the expansion zone (3) in order to achieve the necessary width correction of the tubular fabric.

2. Method as claimed in claim 1, in which the tubular fabric is guided through a gap between squeezer rollers at the end of the expansion zone so that water is removed from it and it is laid flat, characterised in that measured quantities of chemicals are additionally applied on all sides to the wet tubular fabric in the region just before the gab between the squeezer rollers.

3. Apparatus for carrying out the method as claimed in claim 1. containing

a) an expansion zone (3) which is defined by an upper and lower sealing point (2a, 7) against the escape of air from the tubular fabric (1) and has a nozzle arrangement (4) in the region between these sealing points.

b) a width measuring arrangement (17) which is arranged behind the upper sealing point (7) of the expansion zone (3) for the tubular fabric in its flat state, characterised in that

c) the expansion zone (3) is provided directly in the region of the last wet treatment section (2) of a wet treatment apparatus, and the transition region (2a) between this last wet treatment section and the expansion zone forms the lower sealing point;

d) the nozzle arrangement (4) is connected to the width measuring arrangement (17) for control purposes via a computer (16) in such a way that the action of air on the nozzle arrangement can be controlled as a function of the difference between the measured and predetermined fabric widths (WB).

4. Apparatus as claimed in claim 3, characterised in that the transition region (2a) between the last wet treatment section (2) and the expansion zone (3) contians an arrangement, especially a sliding grate (6), which advances the wet tubular fabric (1) without tension and forms a material store.

5. Apparatus as claimed in claim 3, characterised in that the width measuring apparatus is a photoelec- tronic measuring arrangement operating with a light curtain (18).

6. Apparatus as claimed in claim 3, characterised in that a continuously regulating compressed air dosaging valve (13) which is associated with converter or setting regulator (15, 29) connected to the computer (16) is provided in the control connection between the computer (16) and the nozzle arrangement (4).

7. Apparatus as claimed in claim 3, characterised in that the nozzle arrangement (4) contains two swivel arms (8a, 8b) on the free ends of which are mounted compressed air nozzles (9) between which the tubular fabric (1) is guided.

8. Apparatus as claimed in claim 3 and for carrying out the method as claimed in claim 2, characterised in that the upper sealing point of the expansion zone (3) is formed by squeezer rollers (7) and an application and spraying arrangement (19) for spraying chemicals onto the tubular fabric (1) is provided immediately before the squeezer rollers (7).

9. Apparatus as claimed in claim 8, characterised in that the application and spraying arrangement (19) contains two spray pipes (20) arranged on both sides of the tubular fabric (1) and a circulating pump (21) which is connected ont the one hand to the spray pipes and on the other hand to a fluid collecting arrangement (24) below the last wet treatment section (2), and a dosaging arrangement (25) for the substances to be applied is connected to the intake pipe (23) of the circulating pump.

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