GB2051899A

GB2051899A - Dyeing cloth

Info

Publication number: GB2051899A
Application number: GB8019577A
Authority: GB
Original assignee: Sando Iron Works Co Ltd
Current assignee: Sando Iron Works Co Ltd
Priority date: 1979-06-15
Filing date: 1980-06-16
Publication date: 1981-01-21
Also published as: DE8015549U1; DE3021954A1; MX153681A

Abstract

Cloth is dyed within a steam chamber 1 in which a pair of endless net conveyors 2 and 2' are arranged one above the other with the lower run of the upper conveyor parallel to and spaced from the upper run of the lower conveyor thereby to define a gap which serves as a cloth passage. The width of the gap is in the range of from 50 to 200 mm, and a plurality of dye solution nozzles 3 are provided alternately above and below the cloth passage to direct transverse jets of hot dye solution into the cloth passage through the adjacent conveyor run. The jet force causes a cloth 8 being treated to follow a snake-like undulating path as the cloth is advanced along the cloth passage on operation of the conveyor 2 and 2', thereby vibrating the cloth. Excess dye solution not absorbed is collected in a catch tank 4 provided with a steam heater tube 6, and is recirculated by a pump to the nozzles 3. <IMAGE>

Description

SPECIFICATION Methods of and apparatus for dyeing cloth This invention relates to methods of and apparatus for dyeing a cloth.

Conventional commercial methods for dyeing a long cloth may roughly be classified into two groups, one being to subject a cloth soaked with a prescribed dye solution to wet heat treatment to fix the dye on the cloth, and the other being to immerse a cloth repeatedly in a liquid tank filled with a prescribed dye solution. The former dyeing method is effective, for instance, for print dyeing, but frequently causes non-uniform dyeing due to insufficient or uneven absorption of the dye solution when plain dyeing is being performed. The latter method to some extent eliminates the difficulties of the former method, but necessitates the uneconomic use of a large quantity of dye solution, and moreover, since there is a large quantity of waste solution to be discharged every time a dyeing operation is completed, safe disposal of the solution can cause problems.

In both of these two methods, a cloth when transported is subjected to tension, and this results in a deterioration in the 'touch' or 'feel' of the cloth, as well as in its bulkiness, stretchability and shrinkability when the dyeing is completed. In particular, when a high temperature type of reactive dye is used, satisfactory temperature control at higher temperatures is difficult, and thus it is not easy to obtain good results.

It is an aim of this invention to offer a method of and apparatus for dyeing a cloth, in which the difficulties of the above-mentioned conventional methods are at least reduced somewhat.

According to one aspect of this invention, there is provided a method of dyeing a cloth, comprising transporting a cloth through a cloth passage provided in a wet-heat treatment chamber, the cloth passage being defined by a pair of endless net conveyors arranged one above the other with the lower run of the upper conveyor substantially horizontal, parallel to and spaced from the upper run of the lower conveyor, the gap between said runs serving as the cloth passage, and directing jets of hot dye solution the cloth as the cloth is advanced along the cloth passage on operation of the conveyors, the jets extending transversely of the length of the passage and being arranged alternately from above and below the passage.

It will be appreciated that as the two conveyors are operated with the adjacent runs moving in the same sense, the cloth is moved along the cloth passage in a state of no tension. The force of the jets of dye solution cause the cloth to take up a snake-like undulating attitude alternately contacting the two adjacent runs, and because the cloth is subjected to the strong jet force of the hot dye solution, the cloth is soaked with the dye solution right to the interior thereof. Accordingly, the cloth is dyed uniformly in a short time, and simultaneously, the cloth is given an excellent 'touch' or 'feel' and has an appropriate stretchability, shrinkability and bulkiness.

It is preferably to recirculate the dye solution jetted at the cloth, for sparing the dye solution. The method may be applied by passing a loop of the cloth circulatively through the cloth passage in the treatment chamber so as to secure uniform dyeing, or by transporting a long web of the cloth successively into the treatment chamber through a cloth inlet, then along the cloth passage and finally out of the treatment chamber through a cloth outlet.

In the case in which the cloth is circulated, it may be advantageous for certain types of dye to subject the cloth to a wet-heat treatment after leaving the outlet from the cloth passage but before the cloth re-enters the inlet to the cloth passage. Such a wet-heat treatment may comprise elevating the temperature of an upper part of the treatment chamber interior and then causing-the cloth to follow an elongated path in that upper part of the chamber.

According to another aspect of this invention, there is provided apparatus for dyeing a cloth, comprising a treatment chamber having means to raise the internal temperature thereof, a pair of endless net conveyors provided one above the other with the lower run of the upper conveyor substantially horizontal, parallel to and spaced from the upper run of the lower conveyor, the gap between said runs serving as a cloth passage, a plurality of jet nozzles provided along the cloth passage alternately thereabove and therebelow and each arranged to direct a transverse jet of dye solution through the adjacent conveyor run into the cloth passage, and a dye solution catch tank provided below the net conveyors to collect jetted dye solution.

Preferably, means are provided to recirculate dye solution collected in the catch tank back to the nozzles for jetting therefrom. The treatment chamber may be arranged to circulate the cloth repeatedly through the cloth passage in the treatment chamber, in which case a wet-heat treatment device conveniently is provided in an upper part of the treatment chamber and through which the cloth is passed after leaving the cloth passage but before re-entering the passage. Alternatively, the treatment chamber may have a cloth inlet and a cloth outlet, and means are provided successively to pass a long web of cloth through the cloth inlet, the cloth passage and then the cloth outlet.

By way of example only, three specific embodiments of this invention will now be described in detail, reference being made to the accompanying drawings, in which: Figure 1 is a diagrammatic sectional view of the first embodiment of apparatus of this invention, for circulating a cloth in a steamer; Figure 2 is a similar view of a second embodiment, for transporting a cloth continuously through a steamer; Figure 3 is a similar view of a further embodiment in which a device to subject a cloth to a wet heat treatment is interposed in the path of a circulating cloth; and Figure 4 is a sectional front view of the apparatus of Figure 3.

Referring initially to Figure 1, there is shown the first embodiment of apparatus, arranged for the dyeing of a particular length of cloth by circulating the cloth in a steamer or a wet-heat treatment chamber, under normal atmospheric pressure. The apparatus comprises a steamer body 1 arranged so that the internal atmosphere can be a wet heat at normal atmospheric pressure, A pair of endless net conveyors having a sufficient permeability are provided one above the other so as to have the lower run of the upper conveyor parallel to and spaced from the upper run of the lower conveyor, thereby to define a gap a which serves as a horizontal cloth passage.A plurality of jet nozzles 3 are disposed outside the cloth passage to jet hot dye solution to the cloth through the adjacent conveyor run, the nozzles being arranged alternatively above and below the cloth passage and each providing a jet which extends across the passage. A dye solution catch tank 4 is disposed beneath the lower conveyor 2' and is fitted with a steam pipe 6 for heating dye solution 5 in the tank and a temperature regulator 7 for controlling the temperature of the dye solution. The hot dye solution in the dye solution catch tank 4 is fed to the nozzles 3 for jetting therefrom by means of a pump (not shown in the figure) so that the solution is recirculated.

The cloth.8 to be dyed has a particular length and the ends thereof are joined to form an endless loop. As to the type of cloth to be dyed, various kinds may be cited, such as a woven cloth or a knitted georgette comprising strongly twisted yarns of 100% polyester filaments, or cloths falling in a broad class comprising 65% polyester and 35% cotton.

In this apparatus, it is most important that the height of the cloth passage -- that is the width of the gap a - should properly be set to an appropriate value. The width of the gap should be determined so that the cloth is strongly beaten and crumpled and becomes sufficiently permeable to the dye solution when hot dye solution is directed thereat causing the cloth to follow a zig-zag path as the cloth is advanced along the cloth passage. The cloth should thus take up snake-like undulations, as shown in Figure 1.

Although an appropriate width for the gap a depends on the kind of cloth to be dyed, whether the cloth is thick or thin, on the jet pressure of the dye solution and so on, it is desirable that the height of the undulations of the cloth (corresponding to the width of the gap) is as large as possible. This is because the cloth is strongly vibrated by the jet force of the dye solution, while the cloth is following the undulating path along the cloth passage, and the vibration is effective at rendering the cloth permeable to the dye solution whilst simultaneously beating and crumpling the cloth. When the gap between the two conveyors is too narrow, the length of the cldth on an upwardly directed or downwardly directed path is too short to give any effective vibration.On the other hand, when the gap is too broad, the cloth does not strike sufficiently firmly on the conveyors, so that the cloth does not follow the undulating path but instead floats in the gap, and therefore the cloth is not transferred smoothly along the passage in accordance with the operation of the two conveyors.

To establish an appropriate width for the gap, the relation between the width of the gap a and the area b of cloth contacting a conveyor at each turning point of an undulation (determined in terms of the length of cloth) was determined experimentally by varying the kind of cloth to be treated. The jet pressure of the dye solution and the pitch of the jet nozzles were kept constant. The results are shown in Table 1.

Conditions: Jetting speed 48 m/sec.

Temperature 980C Pitch of jet nozzles 350 mm Width of jet nozzles 8 mm Cloths tested: Width Length cm cm No. 1 T/CGabardine 91.8 x 103.9 No. 2 T/C Weather 90.6 x 104.0 No. 3 Cotton Gabardine 92.6 x 104.6 No. 4 T/C Mixed Weave 107.8 x 100.7 TABLE 1 Test of the Formation of Snake-like Undulations

Width of the Gap, a mm Cloth 20 50 100 150 200 250 No. 1 130 120 112 110 88 50 b No. 2 143 115 110 110 95 60 mm No. 3 140 120 115 115 95 55 No. 4 140 120 110 110 85 65 To transport a cloth smoothiy along the passage so as to form snake-like undulations whilst in a relaxed state and with no tension, it was demonstrated that an appropriate area for the cloth contacting the conveyor per turning point of an undulation was in the range of from 120 to 85 mm, in terms of the length of the cloth. From the results in Table 1, therefore, it is concluded that the appropriate gap width corresponding to the dimension b is in the range of from 50 to 200 mm for a wide variety of the cloth to be treated.

The dyeing of a cloth using the apparatus of Figure 1 is performed, for instance, as follows. A cloth 8 of a particular length is made endless by sewing together its two ends, and is then introduced in the steamer body 1 to take up the path shown in the figure, passing around various guide rollers. Dye solution 5, for instance comprising a dispersive dye, is put in the dye solution catch tank 4 and heated to a temperature of about 980C. Then, the cloth is circulated by operating the two net conveyors 2 and 2', and jets of heated dye solution are directed crosswise at the cloth alternately from both sides thereof through the jet nozzles 3, by means of the pump (not shown). Due to the jet force of the hot dye solution directed cross-wise at the cloth, the cloth takes up the undulating path in the cloth passage alternately contacting the two conveyors.The cloth alternately and repeatedly strikes the two conveyors, thereby being beaten and crumpled as well as vibrated, so that the cloth becomes soaked with the dye solution, right to the interior thereof. Therefore, the cloth is dyed effectively and uniformly, and simultaneously suitably crimped to give the cloth appropriate stretchability, shrinkability and bulkiness and an excellent 'touch' or 'feel'. This apparatus is thus particularly suitable for producing a uniformly dyed cloth.

Another embodiment of the apparatus of this invention is shown in Figure 2, which apparatus is intended continuously to dye a long cloth. Insofar as this apparatus is similar to that described above, like parts are given like reference characters and will not be described again. In Figure 2, the steamer body 1 has a cloth inlet 9 and a cloth outlet 10 for a long web of cloth 8', but in other respects the construction of the apparatus will easily be understood from Figure 2 by referring to the description of the apparatus shown in Figure 1. The width of the gap a between the two endless net conveyors (the height of the cloth passage) is also similarly in the range of from 50 to 200 mm.

The cloth 8' is transported continuously through the cloth passage while receiving the jet force of the heated dye solution as in the first embodiment, and since the cloth passage is relatively long, the cloth is effectively dyed and crimped by the time the cloth leaves the steamer body 1', without needing to be recirculated. This type of apparatus is thus able to achieve high productivity and is suitable for mass-production.

The third embodiment of apparatus of this invention is shown in Figures 3 and 4 and is similar to that shown in Figure 1 but has a device interposed in the recirculating path of the cloth, which device subjects the cloth to steaming or a wet heat treatment at a high temperature. This embodiment is particularly effective at applying a high temperature type of reactive dye.

The general construction of the steamer body 1", the pair of endless net conveyors 2 and 2', the plurality of jet nozzles 3, the dye solution catch tank 4 and other parts is essentially the same as in the first embodiment (Figure 1). This third embodiment however includes a plurality of guide rollers 12 provided in the steamer body 1" above the upper net conveyor 2, arranged to transport an endless loop of cloth 8" to be dyed along a zig-zag path as the cloth is advanced from the outlet of the cloth passage back to the inlet thereof. A hot air pipe 13 is provided above the guide rollers 12, the pipe having a plurality of jet nozzles 14 through which hot air may issue, for instance at a temperature of about 1 500C to 1 800 C, into the steamer body, so as to maintain at least the upper part of the steamer body within this temperature range.

Water vapour evaporated from the dye solution jetted at the cloth as the cloth advances along the cloth passage diffuses throughout the interior of the steamer body in the form of a mist of the dye solution, and is heated sufficiently in the upper part of the steamer body by the hot air issuing from jet nozzles 14, so that the space in the upper part of the steamer body serves as a wet-heat treating chamber.

As the endless loop of cloth 8" advances along the cloth passage between the two endless net conveyors, the cloth becomes swollen and soaked with hot dye solution right to the interior thereof.

Then, the cloth follows the zig-zag path over the guide rollers 12 in the upper part of the steamer body while being subjected to a wet heat treatment at a high temperature. These processes are repeated, as the cloth is circulated within the steamer body. Therefore, even when a high-temperature reactive dye is employed, effective dyeing can still be performed. Moreover, although the cloth is subjected to some tension as the cloth is passed over the guide rollers, the cloth is beaten and crumpled under conditions of no tension on passing through the cloth passage between the two conveyors, so the cloth can still be crimped suitably to render the cloth appropriately bulky, stretchable and shrinkable.

It will be appreciated that the described embodiments all allow the uniform dyeing of a cloth in a relatively short period, although the apparatus is simple, only sparingly uses dye solution and economically uses other resources. The cloth dyed by the apparatus is suitably crimped to give the cloth an excellent 'touch' or 'feel' bulkiness, stretchability and shrinkability.

Claims

1. A method of dyeing a cloth, comprising transporting a cloth through a cloth passage provided in a wet-heat treatment chamber, the cloth passage being defined by a pair of endless net conveyors arranged one above the other with the lower run of the upper conveyor substantially horizontal, parallel to and spaced from the upper run of the lower conveyor the gap between said runs serving as the cloth passage, and directing jets of hot dye solution at the cloth as the cloth is advanced along the cloth passage on operation of the conveyors, the jets extending transversely of the length of the passage and being arranged alternately from above and below the passage.

2. A method as claimed in claim 1, in which jetted dye solution not absorbed by the cloth is collected and then recirculated to the jets.

3. A method as claimed in claim 1 or claim 2, in which the clother is circulated within the treatment chamber, by being passed repeatedly along the cloth passage.

4. A method as claimed in claim 3, in which the cloth is subjected to a wet-heat treatment after leaving the outlet from the cloth passage but before the cloth re-enters the inlet to the cloth passage.

5. A method as claimed in claim 4, in which the wet heat treatment comprises elevating the temperature of an upper part of the treatment chamber interior and then causing the cloth to follow an elongated path in that upper part of the chamber.

6. A method as claimed in claim 1 or claim 2, in which the cloth is transported continuously in turn into the treatment chamber, along the cloth passage, and then out of the treatment chamber.

7. A method as claimed in any of the preceding claims, in which the jets of dye solution cause the cloth alternately to contact the two adjacent runs of the conveyors, thereby following an -undulating path along the cloth passage.

8. A method as claimed in any of the preceding claims, in which the width of the cloth passage between the adjacent conveyor runs is in the range of from 50 to 200 mm.

9. A method of dyeing a cloth substantially as hereinbefore described, with reference to any of the accompanying drawings.

10. Apparatus for dyeing a cloth, comprising a treatment chamber having means to raise the internal temperature thereof, a pair of endless net conveyors provided one above the other with the lower run of the upper conveyor substantially horizontal, parallel to and spaced from the upper run of the lower conveyor, the gap betwen said runs serving as a cloth passage, a plurality of jet nozzles provided along the cloth passage alternately thereabove and therebelow and each arranged to direct a transverse jet of dye solution through the adjacent conveyor run into the cloth passage, and a dye solution catch tank provided below the net conveyors to collect jetted dye solution.

11. Apparatus for dyeing a cloth as claimed in claim 10, wherein means are provided to recirculate dye solution collected in the catch tank back to the nozzles for jetting therefrom.

12. Apparatus for dyeing a cloth as ciaimed in claim 10 or claim 1 wherein the treatment chamber is arranged to circulate the cloth repeatedly through the cloth passage in the treatment chamber.

13. Apparatus for dyeing a cloth as claimed in claim 12, wherein a wet-heat treatment device is provided in an upper part of the treatment chamber and through which the cloth is passed after leaving the cloth passage but before re-entering the passage.

14. Apparatus for dyeing a cloth as claimed in claim 13, wherein the wet-heat treatment device comprises a plurality of guide rollers provided above the net conveyors and arranged to define a zig-zag path for the cloth being circulated.

1 5. Apparatus as claimed in claim 1 3 or claim 14, wherein there is a plurality of nozzles in the upper part of the treatment chamber and means to supply air at an elevated temperature to the nozzles thereby to raise the temperature in the upper part of the treatment chamber.

1 6. Apparatus for dyeing a cloth as claimed in claim 10 or claim 11, wherein the treatment chamber has a cloth inlet and a cloth outlet, and means are provided successively to pass a lony web of cloth through the cloth inlet, the cloth passage and then the cloth outlet.

1 7. Apparatus for dyeing a cloth as claimed in any of claims 10 to 16, wherein the width of the gap determined between the runs of the two endless net conveyors serving as the cloth passage is in the range of from 50 to 200 mm.

1.8. Apparatus for dyeing a cloth substantially as hereinbefore described with reference to and as illustrated in Figure 1 or in Figure 2 or in Figures 3 and 4 of the accompanying drawings.