GB2051158A

GB2051158A - Continuous Dyeing of a Cloth

Info

Publication number: GB2051158A
Application number: GB8016304A
Authority: GB
Original assignee: Sando Iron Works Co Ltd
Current assignee: Sando Iron Works Co Ltd
Priority date: 1979-05-18
Filing date: 1980-05-16
Publication date: 1981-01-14
Also published as: IT8022169A0; DE3018448A1; IT1131188B

Abstract

Dyeing of a cloth web, by continuously passing the web through a steamer 1 fitted with inlet and outlet seal mechanisms 4 and 5. The cloth is saturated with a dye solution 42 and is then passed along a cloth passage a, defined by the gap between endless net conveyors 61 and 62. Nozzles 7 are arranged to direct dye solution jets through the permeable conveyors 61 and 62 into the passage a, and this causes the moving cloth to follow a zig-zag path, ensuring the dye solution penetrates the cloth fibres. Hot washing liquid may issue through further nozzles 72 [Fig. 2], disposed adjacent the outlet from the cloth passage, to perform a preliminary washing step. A plurality of guide rollers 11 [Fig. 3] may be disposed to cause the cloth to follow a zig-zag path after entering the steamer, to perform a preliminary dye- fixing step by simple steaming. <IMAGE>

Description

SPECIFICATION Apparatus and Methods for the Continuous Dyeing of a Cloth This invention relates to apparatus for and methods of continuously dyeing a cloth in a high pressure steamer.

In recent years, various kinds of synthetic fibres have been developed to answer the shortage of natural fibres, and polyester fibres have in particular been produced on a very large scale for the manufacture of cloth. However, polyester fibres are inferior to many natural fibres so far as the fixing characteristics for dyes (i.e. the 'dyeability') and the 'touch' or 'feel' are concerned.

When attempting to produce a dyed polyester fibre cloth, it is usual in the first place to subject the cloth to a treatment which crimps the cloth for improving the feel thereof, and then to dye the cloth. Cloth treatments such as these of necessity use large quantities of water to wash the cloth as the treatments proceed. Since the crimping of the cloth and the dyeing thereof are separately performed, large quantities of heat energy, labour and water resources are uneconomically utilised.

The present invention stems from the economic disadvantages of the above, described treatments for a polyester fibre cloth. The invention thus aims at allowing both the crimping and the dyeing of a cloth continuously and simultaneously in a single high pressure steamer, thereby reducing the heat energy and water consumptions, as well as the labour costs of the described conventional processes.

According to one aspect of this invention, there is provided a method of continuously dyeing a cloth in a high pressure steamer having a saturated internal atmosphere at a high temperature and a high pressure, comprising transporting the cloth continuously through a cloth passage defined by the gap between the two adjacent generally-parallel runs of two endless net conveyors disposed one above another in the steamer, and jetting dye solution through the runs of the conveyor at the cloth from jet nozzles disposed outside and spaced along the length of the cloth passage as the cloth is tranported therealong on operation of the conveyors, which jets of dye solution cause the cloth to follow an undulating path along the length of the passage.

It will be appreciated that by jetting the dye solution at the cloth, not only is the cloth fully impegnated with the dye, giving good dyeing characteristics, but also the cloth is sufficiently crimped by being forced to follow the undulating path between the adjacent runs of the conveyors: this serves to improve the 'touch' or 'feel' of the final product.

The efficiency can further be enhanced by jetting a washing liquid (such as hot water) at the cloth as the cloth is transported through the outlet part of the cloth passage, to perform a preliminary washing of the cloth. Such a preliminary washing step is most effective, as the cloth is in a swollen state as the cloth leaves the cloth passage.

By providing more than two endless net conveyors above one another within the steamer, a cloth passage of considerable length can be formed by the gaps, in series, between the conveyors; if the cloth has dye solution jetted thereat for at least the major length of the passage, efficient use is made of the space within the steamer. Another possibility is however to constrain the cloth to follow a zig-zag path by being passed around a plurality of guide rollers disposed within the steamer, whereby the cloth is subjected to a preliminary dye-fixing step by being steamed.

To ensure a satisfactory improvement in the feel of the cloth, the transport conditions through the cloth passage should be adjusted such that the cloth is not subjected to any substantial tension-for instance by adjusting the jet pressures and the transport speed.

According to another aspect of this invention there is provided apparatus for the continuous dyeing of a cloth, comprising a high pressure steamer having means to maintain an internal wet heat atmosphere at high temperature and pressure and means for transporting a cloth continuously therethrough which means comprises two endless net conveyors each being permeable to liquids and arranged one above the other with two adjacent runs generally parallel so that the gap therebetween defines a cloth passage along which the cloth is passed, there being a plurality of dye solution jet nozzles disposed outside and spaced along the length of the passage to direct dye solution into the passage through the runs of the conveyors defining the passage.

Preferably, further jet nozzles are provided at the outlet end portion of the cloth passage, there being means to pump washing liquid to the further jet nozzles, thereby to effect preliminary washing of a cloth being dyed.

The space within the steamer can be utilised more efficiently by providing more than two net conveyors one above the others and the gaps therebetween together defining the cloth treatment passage, means being provided to transport cloth being treated in sequence through the gaps. Alternatively, a plurality of guide rollers may be disposed to provide a zig-zag path along which the cloth is passed after the cloth enters the steamer but before the cloth enters the treatment passage, to subject the cloth to a steaming dye-fixing treatment.

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 transverse sectional view of a first embodiment of apparatus constructed in accordance with the invention; Figure 2 is a similar view of a second embodiment: and Figure 3 is a similar view of a third embodiment.

Referring initially to Figure 1, there is shown a steamer body 1 for treating a cloth under wet heat conditions at high temperature and high pressure (i.e. above the boiling point of water and super atmospheric pressure). The steamer body 1 has a cloth inlet 2 and a cloth outlet 3, which are respectively fitted with an inlet seal mechanism 4 and an outlet seal mechanism 5. These seal mechanisms are arranged to allow the continuous passage of a cloth through the steamer body 1 whilst substantially preventing the leakage of the internal wet heat atmosphere. The inlet seal mechanism includes a pair of sealing rubber rollers 4, which are pressed together to form a nip through which the cloth may pass, and a liquid seal tank 42 provided between the sealing rubber rollers 4, and the steamer body interior.A number of squeeze bars 43 are disposed inside the tank 42 to squeeze the cloth as it passes therebetween.

The outlet seal mechanism 5 includes a pair of sealing rubber rollers 5, which are pressed together to form a nip through which the cloth may pass and a slow cooling tank 52 provided between the sealing rubber rollers 5, and the steamer body interior.

A pair of endless net conveyors 6, and 62 are provided in the steamer body 1, one above the other so that the adjacent opposed runs define a gap serving as a cloth passage a. A plurality of liquid jet nozzles 7 are provided along the length of the passage a, alternately above and below the passage so as to be able to jet a dye solution through the adjacent run of a net conveyor into the passage a. A liquid catch tank 8 is provided beneath the lower net conveyor 62 to receive the dye solution jetted out of the nozzles 7, the dye solution accumulating in the catch tank 8 being recirculated to the jet nozzles 7 by means of a pump (not shown in the Figure).

Catch plates 9 are suitably positioned to prevent water droplets condensing on the steamer body walls falling on to the cloth being dyed.

The dyeing of a cloth 10 by this apparatus is as follows. Initially, the interior of the steamer body 1 is maintained at about 1200 to 1 550C, at a super atmospheric pressure to provide wet heat conditions. The liquid seal tank 42 is filled with the required dye solution, and the slow cooling tank 52 is filled with cooling water. Then, the cloth 10 is introduced into the steamer 1 through the inlet seal mechanism 4 and passed through the cloth passage a, formed between the net conveyors 6, and 62, by the movement of the conveyors as shown by the arrows.

The cloth is impregnated with the dye solution in the liquid seal tank 42 and receives further dye solution jetted thereat from the jet nozzles 7, provided alternately along the top and bottom of the cloth passage. The jets are sufficiently strong to cause the cloth to take up a 'snaky' or zig-zag like configuration, so that as the cloth advances along the passage the cloth follows an undulating path. This causes the cloth to swell somewhat, so that the dye solution may permeate the interior of the yarns (or fibres) constituting the cloth. In this way, the dye becomes firmly fixed on and in the yarns of the cloth. Furthermore, since the cloth effectively is beaten and crumpled due to the vibrations thereof caused by the dye solution jetted thereat, the cloth can become crimped, thus simultaneously improving the feel of the cloth.

Figure 2 shows a second embodiment of apparatus of this invention, somewhat similar to that just described: like parts are given like reference characters and will not be described in detail again. The embodiment of Figure 2 differs however from that of Figure 1 in that four endless net conveyors 61, 62, 63 and 64 are provided one above another and parallel to each other, whereby three cloth passages a, b and c are defined by the gaps between the adjacent opposed runs of the conveyors.The liquid jet nozzles are divided into two groups 71 and 72 the former group 71 being disposed to direct dye solution into the major parts of the cloth passages, whereas the nozzles of the latter group 72 are at the outlet end of the cloth passage c, and are adapted to spray hot washing liquid (e.g. water) at the cloth to perform preliminary washing thereof after the dyeing is completed. In Figure 2, five such nozzles 72 are shown. Two liquid catch tanks 8, and 82 are provided, respectively separately to receive the dye solution and the washing water.

In this embodiment, four net conveyors are provided in one steamer body to utilise fully the space in the steamer body thereby to provide a long cloth passage. Thereore, it is possible to use a relatively high cloth transporting speed, and dyeing can easily be completed economically.

This apparatus is thus quite suitable for mass production of dyed cloth. Furthermore, in this example, the end part of the total cloth passage is utilised to perform a preliminary washing of the dyed cloth, to facilitate the final washing of the cloth after the cloth has left the steamer. Since the preliminary washing is performed by jets of hot water to the cloth, the washing water permeates yarns or fibres of the cloth, up to the cores thereof, whilst in a swollen state, and consequently the washing is very effective.

Figure 3 shows a third embodiment of apparatus again similar to that of Figure 1, and like parts are given like reference characters. In this third embodiment, however, a plurality of guide rollers 1 1 are provided to constrain the cloth to follow a zig-zag path in an upper part of the steamer body prior to the cloth entering the cloth passage c defined by the gap between a pair of endless net conveyors 63 and 64. The liquid jet nozzles are divided into two groups 7, and 72 respectively to jet a dye solution and hot washing water to the cloth, as in the second embodiment (Figure 2).

The cloth soaked with a dye solution in the liquid seal tank 42 is dyed firstly by a steaming step as the cloth is passed around the guide rollers 1 whereafter the cloth is treated in the cloth passage c in the same manner as in the first embodiment (Figure 1). This apparatus is particularly suitable for the dyeing of a cloth comprising filaments.

As will be appreciated from the foregoing, a cloth to be treated is fed continuously through a high pressure steamer having an internal saturated atmosphere at high temperature and high pressure. The cloth is soaked with a dye solution and is then passed through a cloth passage defined by the gap between the adjacent runs of two or more endless net conveyors provided one above the other while a dye solution is jetted thereat. The cloth can be steamed to perform a preliminary dyeing step, before the cloth enters the passage and moreover a preliminary washing step can be performed at the outlet end portion of the cloth passage.

Both the wet heat at a relatively high temperature and, particularly, the jet force of the dye solution promotes dyeing, so that the dyeing of a cloth is most effectively performed.

Furthermore, since the cloth follows a snake-like path through the cloth passage while receiving the jet force of the dye liquid, the cloth is crimped and this can simultaneously improve the feel of the cloth. Also, an effective preliminary washing step greatly facilitates the final washing, performed outside the steamer.

Claims

1. A method of continuously dyeing a cloth in a high pressure steamer having a saturated internal atmosphere at a high temperature and a high pressure, comprising transporting the cloth continuously through a cloth passage defined by the gap between the two adjacent generally parallel runs of two endless net conveyors disposed one above another in the steamer, and jetting dye solution through the runs of the conveyor at the cloth from jet nozzles disposed outside and spaced along the length of the cloth passage as the cloth is tranported therealong on operation of the conveyors, which jets of dye solution cause the cloth to follow an undulating path along the length of the passage.

2. A method for dyeing a cloth as claimed in claim 1, in which a washing liquid is jetted at the cloth as the cloth is tranported through the outlet part of the cloth passage, to perform a preliminary washing of the cloth.

3. A method of dyeing a cloth as claimed in claim 1 or claim 2, in which more than two endless net conveyors are provided above one another within the steamer and the cloth is passed successively through the gaps therebetween whilst having dye solution jetted thereat.

4. A method as claimed in any of the preceding claims, in which the cloth is soaked with dye solution as the cloth enters the steamer.

5. A method of dyeing a cloth as claimed in claim 4, in which, before the cloth enters the cloth passage, the cloth is constrained to follow a zigzag path by being passed around a plurality of guide rollers disposed within the steamer, whereby the cloth is subjected to a preliminary dye-fixing step by being steamed.

6. A method as claimed in any of the preceding claims, in which the transport conditions through the cloth passage are adjusted such that the cloth is not subjected to any substantial tension.

7. A method of continuously dyeing a cloth in a high pressure steamer substantially as hereinbefore described with reference to Figure 1 or to Figure 2 or to Figure 3 of the accompanying drawings.

8. Apparatus for the continuous dyeing of a cloth, comprising a high pressure steamer having means to maintain an internal wet heat atmosphere at high temperature and pressure and means for transporting a cloth continuously therethrough which means comprises two endless net conveyors each being permeable to liquids and arranged one above the other with two adjacent runs generally parallel so that the gap therebetween defines a cloth passage along which the cloth is passed, there being a plurality of dye solution jet nozzles disposed outside and spaced along the length of the passage to direct dye solution into the passage through the runs of the conveyors defining the passage.

9. Apparatus as claimed in claim 8, wherein further jet nozzles are provided at the outlet end portion of the cloth passage, there being means to pump washing liquid to the further jet nozzles, thereby to effect preliminary washing of a cloth being dyed.

10. Apparatus as claimed in claim 8 or claim 9, wherein more than two net conveyors are provided in the steamer and the gaps therebetween together define the cloth treatment passage, means being provided to transport cloth being treated in sequence through the gaps.

11. Apparatus as claimed in claim 8 or claim 9, wherein a plurality of guide rollers are disposed to provide a zig-zag path along which the cloth is passed after the cloth enters the steamer but before the cloth enters the treatment passage.

12. Apparatus as claimed in any of claims 8 to 11, wherein the steamer is provided with roll nip seals to allow a continuous transport of cloth therethrough whilst preventing substantial leakage from the steamer.

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