US3690814A

US3690814A - Method for continuous wet treatment of a textile web

Info

Publication number: US3690814A
Application number: US14361A
Authority: US
Inventors: Peter Schroeder
Original assignee: Weber Paul AG
Current assignee: Weber Paul AG; PAUL WEBER AG
Priority date: 1969-02-28
Filing date: 1970-02-26
Publication date: 1972-09-12
Anticipated expiration: 1989-09-12
Also published as: CS151543B2; CH301769A4; GB1292497A; CH512941A; DE2006177A1; NL7002758A; FR2037438A5; US3772903A; CH504903A; AT313840B

Abstract

IN A METHOD FOR THE CONTINUOUS WET TREATMENT OF A TEXTILE WEB GUIDED ALONG A ZIG-ZAG PATH IN A BATH FORMED BY A CONTINUOUS COUNTER-CURRENT OF FLOWING TREATMENT LIQUID, THE WEB IS POSITIELY GUIDED ALONG ITS PATH OF MOVEMENT THROUGH THE BATH WHILE BEING SUPPORTED IN A SUBSTANTIALLY UNINTERRUPTED MANNER ALONG THIS PATH. THE EFFECT SIMULTANEOUS BOUNDARY LAYER EXCHANGE ON BOTH SURFACES, THE BOTH SURFACES OF THE WEB ARE ALTERNATELY COMPRESSED AND STRETCHED. THE WEB IS GUIDED OVER PERFORATED ROLLERS AND, WITH RESPECT TO THE MAJORITY OF THESE ROLLERS, THE WEB HAS

A LOOPING ANGLE THEREAROUND IN EXCESS OF 180*. THE PERFORATED ROLLERS ARE ARRANGED SO CLOSE TO EACH OTHER THAT, ALTHROUGH THEY DO NOT TOUCH, THEY FORM PRACTICALLY AN UNINTERRUPTED SUPPORT FOR THE WEB. AT LEAST ONE WIDE-SLOT NOZZLE DIRECTS TREATMENT LIQUID DIRECTLY AGAINST THE TEXTILE WEB IN THE BATH. PREFERABLY, THE ROLLERS HAVE DISPLACEMENT INSERTS THEREIN TO FILL A SUBSTANTIAL PART OF THE INTERIOR OF THE ROLLERS.

Description

Sept. 12, 1912 P. SCHROEDEIR 3,690,814

METHOD FOR CONTINUOUS WET TREATMENT OF A TEXTILE WEB Filed Feb. 26, 1970 3 Sheets-Sheet 1 INVENTOR.

?ETE'R 500305351 Jwflw '4 lm RTTO'RNEVS Sept. 12, 1972 P. SCHROEDER METHOD FOR CONTINUOUS WET TREATMENT OF A TEXTILE WEB Filed Feb. 26, 1970 3 Sheets-Sheet z FIG.2

INVENTOR.

BY 'PETE'R HROEDER FFITO'R N EIS Sept. 12, 1972 P. SCHROEDER 3,690,814

METHOD FOR CONTINUOUS WET TREATMENT OF A TEXTILE WEB Filed Feb. 26, 1970 3 Sheets-Sheet 3 INVENTOR PETE-R SLHRDED 'R RTI'Q'R NEYS United States Patent Int. c1: B05c 3/136 US. Cl. 8-151- 4 Claims ABSTRACT OF THE DISCLOSURE In a method for the continous wet treatment of a textile web guided along a zig-zag path in a bath formed by a continuous counter-current of flowing treatment liquid, the Web is positively guided along its path of movement through the bath while being supported in a substantially uninterrupted manner along this path. To effect simultaneous boundary layer exchange on both surfaces, the both surfaces of the web are alternately compressed and stretched. The web is guided over perforated rollers and, with respect to the majority of these rollers, the web has a looping angle therearound in excess of 180. The perforated rollers are arranged so close to each other that, although they do not touch, they form practically an uninterrupted support for the web. At least one wide-slot nozzle directs treatment liquid directly against the textile web in the bath. Preferably, the rollers have displacement inserts therein to fill a substantial part of the interior of the rollers.

BACKGROUND OF THE INVENTION Known methods for the wet treatment, such as washing, bleaching, steaming, dyeing, impregnating, mercerizing, etc. of textile webs, such as webs of fabrics, knits, mats,

etc., are usually based on the principle of the so-called roll vats, and have a relatively low efficiency.

To intensify the wet treatment processes, it has been proposed to combine repeated squeezing or extraction with repeated bilateral spraying of the textile webs. While these measures result in a certain increase in the efliciency of the wet treatment, they entail a considerable disadvantage that the textile material, subjected to these treatments, undergoes heavy mechanical stress, so that these methods are out of the question for delicate textiles. Also, the bath consumption is disproportionately high. Furthermore, in

many cases it is not desirable that the textile material come in contact with the atmosphere during the treatment,

I as is the case with this proposaldeflecting rollers, and charging it, during its passage between the rollers, with a treatment liquid, preferably from spray pipes.

In another known method, the textile material is immersed in the treatment bath during the entire treatment. In this procedure, it is sought to intensify the effect of the bath on the textile material in various ways, for example in that a flow of the bath is produced to run counter to the direction of movement of the textile web, or by vibrators, etc.

:In the known methods, or in the apparatus developed for practicing the methods, the webs are moved through the bath in insupported relation over long distances, and this precludes the treatment of very delicate fabrics as well is very often required.

For such a wet treatment of textile webs, it must be noted, for one thing, that it is determining, for the quality of the treatment, that the bath concentration be distributed as evenly as possible over the width of the textile web. This can be attained by bath turbulence or through mixing, for example cycling of the treatment bath. Another problem is to get the treatment liquid really to the fiber or into the fiber. The bath particles must essentially pass through two zones, namely at first the boundary layer around the moving fiber and then, in the case of cotton, the actual fiber walls or, in synthetic material, the homogenous fiber. The penetration of these zones occurs by diffusion. Such diffusion processes are known to be relatively slow and to have a disadvantageous effect on the economic efiiciency of an installation. It has therefore been tried to shorten the treatment times as much as possible.

On the basis of Ficks first law of diffusion, it is found that the rate of diffusion is proportional to the concentration gradient. Ficks law of diffusion may be stated as follows:

wherein dm=diffusing quantity F=surface to be traversed dt=diffusion time dx=diffusion path dm/Fdt=rate of diffusion D=diffusion constant dc/dx: concentration gradient dc=concentration difference.

To obtain as favorable as possible a solution in terms of engineering, an attempt must be made to influence the values on the right side of the above equation in such a way that the entire expression becomes a maximum. However, such maximization of the rate of diffusion must not simultaneously lead to high operational costs, but should result in an increase of efficiency. The concentration gradient dx/dx can be made a maximum, from the beginning to the end of the process, if the concentration difference between the bath and the fabric is continuously maintained at as high as possible a value. It follows from this that the textile web must, during the entire process, be immersed in the bath, and the bath must be guided in a continuous counter-current relative to the textile web. This results in a single-bath process.

In order for economic reasons, to make the diffusion paths dx as short as possible, the moving bath must be applied directly on the individual fibers, in order that the concentration difference between the surface and the interior of the fiber will become a maximum and the respective chemicals can diffuse quickly, However, since the fabric web moving in the liquid has a relatively thick boundary layer, it is necessary to break through this layer as quickly and as thoroughly as possible to obtain the desired treatment effect.

SUMMARY OF THE INVENTION This invention relates to the continuous wet treatment of textile webs and, more particularly, to an improved method and apparatus for such treatment which, while handling the web to be treated extremely gently, insure an effective penetration of the boundary layers of the web.

The method and apparatus of the invention provide an increase in the efficiency of the treatment and, thus, a substantial shortening of the required treatment time is attained while, at the same time, the invention method and apparau's provide the possibility of treating extremely delicate webs without danger of damaging the webs.

In the invention method, the textile web, while passing through the treatment bath, is guided positively and supported practically without interruption. For the purpose of simultaneous boundary layer exchange on both surfaces of the Web, the opposite surfaces are alternately stretched and compressed by an alternating bending motion.

The apparatus for performing the method comprises rollers arranged in a channel-type bath vessel and providing a zig-zag deflection of the textile web. The rollers are perforated and are arranged so close together that, while they do not touch, they form practically an uninterrupted support for the textile web.

An object of the invention is to provide an improved method for the continuous wet treatment of textile webs.

Another object of the invention is to provide an improved apparatus for the continuous Wet treatment of textile webs.

A further object of the invention is to provide such a method and apparatus in which the web can be treated extremely gently while insuring an effective penetration of the boundary layers of the web.

Another object of the invention is to provide such a method and apparatus increasing the efficiency of the treatment and decreasing the required treatment time.

A further object of the invention is to provide such a method and apparatus capable of treating extremely delicate webs without danger of damage.

For an understanding of the principles of the invention, reference is made to the following description of typical embodiments thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view through one form of apparatus for performing the method of the invention;

FIG. 2 is a vertical sectional view through another form of apparatus embodying the invention; and

FIG. 3 is a vertical sectional view through still another embodiment of the apparatus for performing the method of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a substantially U-shaped upright vessel 1 accommodates the maximum possible number of

rotatable rollers

2 and 3. These rollers are arranged in the two vertical legs of the vessel in the form of two rolls of rollers which are staggered relative to each other. All of the

rollers

2 and 3 have perforated surfaces, so that treatment liquid can reach the textile web from both sides. Additionally, the perforations prevent building up of a liquid cushion between the textile web 14 and the

rollers

2 and 3, which buildup would increase the tension in the fabric since the effective circumference of the rolls thereby would be increased.

The arrangement of the

rollers

2 and 3 is so selected that they are as near together as possible without touching, so that the free path of textile web 14 between two rolls become so small that web 14 passes through the apparatus supported practically without any interruption. Textile web 14 is guided around

rollers

2 and 3 in meander form, and is passed through the apparatus, filled with treatment bath, in the direction of the arrow and treated by the bath during such passage. As the

rollers

2 and 3 are very close together, the looping angle becomes relatively large and, for most of the rolls, exceeds 180.

Through this special positive guiding of textile web 14 by

rollers

2 and 3, there results, by virtue of the alternately opposite deflection of the textile web, an opening and a closing, which is particularly important for the penetration of the treatment liquid through the boundary layers of the web, in that, with the curvature of the fabric web, the fiber interstices on the inner side are closed and the liquid present therein is squeezed out. At the immediately following subsequent deflection, textile Cit web 14 is deflected in the opposite direction and the previously closed interstices are now opened. The external fiber interstices are thereby enlarged and draw in liquid from the outside.

In this boundary layer, which with the usual roughness is relatively thick, there thus results an exchange flow extending between the fiber surfaces and the boundary layer surfaces. Thereby, the desired concentration gradient is produced directly at the fiber surfaces, in contrast to conventional apparatus wherein the treatment bath at the fiber surfaces has approximately the same concentration as in the fibers themselves, and it is only toward the outer limitations of the boundary layer that there is a concentration difference with the surrounding bath. With these conventional machines, however, the effect of the treatment bath within the relatively thick boundary layer can occur only through a relatively slow diffusion.

The boundary layer penetration is additionally enhanced by the provision of several wide-slot nozzles 4. In view of the relatively high energy consumption needed for operating these nozzles, their use is limited to a small number.

In order that textile web 14 will have as low as possible a tension during the treatment process, all of the

rollers

2 and 3 of the apparatus are driven slip-free, for example by means of chains, so that all rolls necessarily always have the same speed or angular velocity. In addition, the tension between feed roller 5 and

other rollers

2 and 3, including the squeeze rollers 6, is controlled by a dancer roll 7.

The supply of the bath in counter-current to the direction of web movement is effected through the wide-slot nozzle 8 positioned directly below squeeze roller 6, while the other wide-slot nozzles 4 are fed through a line 10 and produce a circulation of the treatment liquid.

To insert the textile web, walls 11 may be removed.

Rollers

2 and 3 are designed as tubular rollers and containing in their interior, displacement bodies 12, whereby the required bath quantity is reduced and, in addition, the treatment bath is channeled.

Turning now to FIG. 2, the apparatus shown therein is suitable preferably for neutralizing or impregnating, and is of somewhat simpler design. However, the basic method of operation is the same as in the embodiment shown in FIG. 1. In contrast to the embodiment shown in FIG. 1, in FIG. 2, a relatively high, upright roll-free inlet and outlet channel means 16 and 17 is provided.

In the embodiment of the invention shown in FIG. 3, the entrance for textile web 14 is provided at the lower end of the vessel. This effects the good seal at the introduction point. The number and arrangement of the rollers depend on the intended treatment process and on the textile material to be treated.

The arrangement of the rolls also may be selected 'so that the textile web passes substantially horizontally or otherwise through the vessel. In particular, for example,

- for a vessel having'a U-shaped vertical section, a possible arrangement is one Where the rollers form a row with their axes side by side.

It is also possible to close the vessel at the top and to put it under pressure, for example by compressed air, whereby the apparatus may be operated at bath temperatures of over C.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. In a method for the continuous treatment of a textile'web guided along a zig-zag path in a bath formed by a continuous counter-current of flowing treatment liquid, the improvement comprising the steps of guiding the web positively along its path of movement through the bath while providing substantially uninterrupted support for the web along its path of movement; alternately compressing and stretching both surfaces of the web to eifect simultaneous boundary layer exchange on both surfaces, and directing at least one jet-like stream of treatment liq uid against said web within the bath at an angle relative to the general direction of movement of the web through the bath.

2. In a method for the continuous wet treatment of a textile web, the improvement claimed in claim 1, includ ing the step of guiding the web over perforated rollers with the majority of the rollers having a looping angle, of the web, in excess of 180.

3. In a method for the continuous wet treatment of a textile web which is moved in meander-like manner through a vessel through which treatment liquid is forced in counter-current to the direction of movement of the web and wherein treatment liquid is additionally applied to the surface of the moving web to penetrate the web, the improvement which comprises that said additionally applied treatment liquid is directed against the web surface within the bath in the form of a jet-like stream at an acute angle relative to the direction of movement of the web through the vessel.

4. The improvement of claim 3, wherein said jet-like stream of treatment liquid causes or assists the countercurrent flow of the treatment liquid through the vessel.

References Cited UNITED STATES PATENTS 3,439,365 4/1969 Bahnsen 68-20 3,457,740 7/1969 Korsch 68-43 X FOREIGN PATENTS 655,302 12/1928 France 6843 378,835 8/1964 Switzerland 68-43 579,622 6/ 1933 Germany 68-175 437,183 11/ 1967 Switzerland 68-43 931,182 9/1947 France 68-43 337,712 11/1930 Great Britain 68-43 WILLIAM 1. PRICE, Primary Examiner US. Cl. X.R.