GB2063944A - Continuous pretreatment and dyeing of cloth - Google Patents

Abstract

Cloth is subjected to pretreatment and dyeing steps on a continuous basis in a single high pressure steamer. The cloth 9 is constrained to follow a zig-zag path by rollers 10 on passing through the steamer from a cloth inlet 2 to a cloth outlet 3. Adjacent the inlet 2, the cloth is soaked with pretreatment liquid and is then subjected to steaming as the cloth passes along a first steaming section of the path. The cloth is then washed on passing through tank 12, soaked with dye solution contained in tank 13 and subjected to further steaming to fix the dye as the cloth passes along a second steaming section of the path. On passing through tank 14 the cloth is washed, and is cooled by liquid contained in tank 8, adjacent the cloth outlet. <IMAGE>

Description

SPECIFICATION A method and apparatus for the continuous pretreatment and dyeing of a long cloth This invention relates to a method for pretreating and dyeing a cloth continuously in a single high pressure steamer, as well as to steamer apparatus for performing the method. The method is particularly but not exclusively applicable to treatment of knitted or woven long lengths of cloth.

In the production of dyed cloth on a commercial scale, it is usual to subject a long cloth to be treated firstly to a pretreatment including desizing, scouring and bleaching, and then to a dyeing step.

Conventionally, a pretreating apparatus such as PERBLE RANGE and a dyeing apparatus such as a vat-steamer are provided in succession, and the cloth, having been subjected to a pretreatment in such a PERBLE RANGE, is taken therefrom to the vat-steamer for the dyeing. Each of the PERBLE RANGE and the vat-steamer consume large amounts of heat energy and additional losses result from the cloth, on being taken out of the PERBLE RANGE, being exposed to the ambient air thus losing heat energy therefrom. The cloth has to be heated again for the dyeing step, so that the overall process suffers from large heat losses and the dyeing efficiency is very low.A further disadvantage of the conventional process is that the capital expenditure for providing a PERBLE RANGE and a vat-steamer separately is large, and considerable floor-space is required in a processing plant for the two separate equipments.

It will thus be appreciated that conventional methods for the continuous pretreating and dyeing of long cloths on a commercial scale have many drawbacks.

It is a principal aim of this invention at least in part to overcome the above-mentioned drawbacks of the described continuous pretreating and dyeing methods for use on a long cloth, so as to allow the pretreatment of a long cloth (such as the desizing, scouring and bleaching) as well as dyeing thereof to be performed continuously in a single high pressure steamer. In this way, the capital cost of the required treating apparatus as well as the amount of floor space taken up can be reduced, and economies made in the amount of heat energy consumed.

According to one aspect of this invention, there is provided a method for pretreating and dyeing a cloth continuously in a single high pressure steamer comprising transporting the cloth to be treated continuously through a high pressure steamer body the interior of which is maintained at super atmospheric pressure and humidity and at a temperature in excess of the boiling point of water, subjecting the cloth previously-soaked with a pretreating solution to a first steaming step in a first steaming section within the steamer, soaking the cloth with dye solution within the steamer after the cloth leaves the first steaming section and then subjecting the cloth to a second steaming step in a second steaming section of the steamer so as to fix the dye on the cloth.

According to another aspect of this invention, there is provided steamer apparatus for performing the just-described method, which apparatus comprises a high pressure steamer having a cloth inlet and a cloth outlet fitted with seal mechanisms to allow the continuous transport of a cloth into, through and out of the steamer, a plurality of guide rolls disposed within the steamer to define a path for the cloth of generally zig-zag form the runs of which are generally up and down, a pretreatment solution tank disposed adjacent the cloth inlet so that cloth entering the steamer passes therethrough to become soaked with pretreatment liquid contained therein, and a dye solution tank disposed in a lower part of the steamer so that the cloth path extends therethrough, whereby a cloth being transported through the steamer becomes soaked with dye solution on passing through said tank.

In the method of this invention, a long cloth soaked previously with a pretreating solution is continuously subjected to a wet heat treatment in a high pressure steamer, the interior of which is maintained at suitable conditions. The pretreatment of the cloth is completed in a first steaming section, and after the cloth is soaked with a dye solution contained for instance in a dye solution tank provided at about the middle of the cloth path through the steamer, the cloth is further steamed so as to fix the dye completely, in a second steaming section of the steamer.

It will be seen that this invention allows the pretreatment and dyeing of a long cloth on a continuous basis, by using a single high pressure steamer body; the dyed cloth can have excellent quality, be produced rapidly and the heat energy consumption can be reduced. Moreover, the capital cost of the apparatus can be relatively low.

By way of illustration only, this invention will now be described in greater detail, and a specific example thereof given, reference being made to the accompanying drawing, which shows a sectional side view of a steamer arranged to perform the method of this invention.

In the drawing, there is shown a high-pressure steamer body 1 within which a long cloth to be treated firstly is subjected to a pretreatment step and then is dyed, these steps being performed continuously under conditions of superatmospheric pressure, high humidity and a temperature in excess of 1 000C. A cloth inlet 2 and cloth outlet 3 are provided at the two ends respectively of the steamer body to allow the continuous passage of cloth 9 therethrough, without allowing substantial leakage of the internal atmosphere.The cloth inlet 2 is fitted with an inlet seal mechanism 4 comprising a pair of rubber seal rolls 6, 6' pressed together to define a nip through which the cloth 9 may pass and a liquid seal tank 7 provided between the rubber seal rolls 6 and 6' and the interior of the steamer body, in which tank a solution necessary for the pretreatment (such as a caustic alkali solution) can be introduced. The cloth outlet 3 is fitted with an outlet seal mechanism 5 and also has a pair of rubber seal rolls 6, 6' pressed together to define a nip through which the cloth 9 may continuously pass, and a slow cooling tank 8 provided between the rubber seal rolls 6 and 6' and the interior of the steamer body, through which tank a controlled amount of cooling water is circulated during operation of the overall apparatus.

On passing through the steamer body from the cloth inlet 2 to the cloth outlet 3, a long web of cloth 9 follows a path defined by a plurality of cloth guide rolls 10, which path is of generally zigzag form with the runs arranged generally up and down. A number of the guide rolls 10 are arranged as dancer rolls 1 to prevent the cloth from becoming slack. A hot water washing tank 12 is provided at about the middle of the cloth path through the steamer body 1, means being arranged to circulate washing water through the tank to maintain a selected amount of water therein. A dye solution tank 13 is provided adjacent the washing tank 12 but further aiong the cloth path means being provided to circulate dye solution through the tank 12 to maintain a particular amount of solution therein.A hot water washing tank 14 is provided in the vicinity of the cloth outlet 3, means again being provided to circulate washing water therethrough. Squeeze bars 1 5 are arranged to squeeze excess treating solution or washing water out of the cloth.

In performing treatments on a cloth 9 with this apparatus, initially the liquid seal tank 7 is filled with a pretreating solution such as a caustic alkali solution, the slow cooling tank 8 with cooling water at a normal temperature, the dye solution tank 13 with a dye solution and the hot water washing tanks 12 and 14 with hot water. These solutions and water are replenished as necessary during performance of the process. The conditions within the high pressure steamer body 1 are then adjusted until the interior is at a superatmospheric pressure, with high humidity and a temperature in the range from 1050 to 1600 C, but desirably at about 1500C. Suitable heating means (not shown in the drawing) are provided for this purpose.

Then, a long cloth 9 to be treated is transported continuously through the steamer body 1. The cloth 9 is soaked with a required amount of pretreating solution on passing through the liquid seal tank 7 provided at the inlet seal mechanism 4, and then steamed as the cloth is transported through the steamer body 1 along the path defined by the plurality of cloth guide rolls 10, until the cloth reaches the hot water washing tank 12. By then, the pretreatment of the cloth is completed. The pretreated cloth 9 is washed in the hot water washing tank 12 to remove the pretreating solution and is then saturated with a dye solution on passing through the dye solution tank 13. The cloth is then again steamed, but in the section of the steamer body following the tank 13, so as to fix the dye impregnating the cloth, before the cloth is preliminarily washed in the hot washing water tank 14.Finally, the cloth is cooled to about 500C in the slow cooling tank 8 and taken out from the steamer body 1 through the outlet 3.

As explained above, the interior of a high pressure steamer body is divided into first and second steaming sections; a cloth soaked with a pretreating solution is subjected to a pretreatment steaming in the first steaming section, whereafter the resultant cloth is soaked with a dye solution and is then subjected to a dye-fixing steaming in the second steaming section, the cloth being transported continuously through the high pressure steamer body during these steaming operations. Therefore, the pretreatment and dyeing of long lengths of cloth can advantageously be performed continuously in a single high pressure steamer. The amount of heat energy consumed can be reduced as compared with conventional methods in which the pretreatment is done with the use of a PERBLE RANGE and the dyeing is done separately in a vat-steamer. The apparatus employed in performing this invention is much simplified, leading to reduced capital costs for the apparatus, as well as reduced power consumptions, typically one half of that required for operating two steamers. Furthermore, in the method of this invention, since the pretreatment and dyeing of a cloth are continuously performed in a single high pressure steamer, the cloth is not subjected to ambient atmospheric conditions between the pretreatment and dyeing steps, and because the cloth is not consequently cooled between these steps, a further energy saving can be made. The invention also has the merit that a dyed cloth having an excellent quality can rapidly be produced.

Claims (9)

1. A method for pretreating and dyeing a cloth continuously in a single high pressure steamer comprising transporting the cloth to be treated continuously through a high pressure steamer body the interior of which is maintained at superatmospheric pressure and humidity and at a temperature in excess of the boiling point of water, subjecting the cloth previously-soaked with a pretreating solution to a first steaming step in a first steaming section within the steamer, soaking the cloth with dye solution within the steamer after the cloth leaves the first steaming section and then subjecting the cloth to a second steaming step in a second steaming section of the steamer so as to fix the dye on the cloth.

2. A method for pretreating and dyeing a cloth as claimed in claim 1, in which a liquid seal tank is provided adjacent a cloth inlet to the steamer and the cloth is soaked with pretreating solution contained within the liquid seal tank as the cloth is introduced into the steamer.

3. A method for pretreating and dyeing a cloth as claimed in claim 1 or claim 2, in which the cloth is subjected to a washing step as the cloth leaves the first steaming section but before the cloth is soaked with dye solution.

4. A method for pretreating and dyeing a cloth as claimed in any of the preceding claims, in which the cloth is subjected to a preliminary washing step as the cloth leaves the second steaming section.

5. A method for pretreating and dyeing a cloth as claimed in any of the preceding claims, in which the cloth is passed through a tank containing cooling liquid prior to the cloth leaving the steamer.

6. A method for pretreating and dyeing a cloth as claimed in any of the preceding claims, wherein the cloth is constrained to follow a generally zigzag path on being transported through the steamer, the runs of the path being generally up and down.

7. A method for pretreating and dyeing a cloth continuously in a single high pressure steamer substantially as hereinbefore described with reference to the accompanying drawing.

8. Steamer apparatus for performing the method of any of the preceding claims, comprising a high pressure steamer having a cloth inlet and a cloth outlet fitted with seal mechanisms to allow the continuous transport of a cloth into, through and out of the steamer, a plurality of guide rolls disposed within the steamer to define a path for the cloth of generally zig-zag form the runs of which are generally up and down, a pretreatment solution tank disposed adjacent the cloth inlet so that cloth entering the steamer passes therethrough to become soaked with pretreatment liquid contained therein, and a dye solution tank disposed in a lower part of the steamer so that the cloth path extends therethrough, whereby a cloth being transported through the steamer becomes soaked with dye solution on passing through said tank.

9. Steamer apparatus as claimed in claim 8 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.