GB2064603A - Dyeing textile fibres - Google Patents

Abstract

Installation for dyeing textile fibres in a vat (1) having supply vats (2, 4) communicating therewith via line (14), is provided with a water inlet (40) for flushing the line (14) and to purge air therefrom in a direction opposite to the supply direction. <IMAGE>

Description

SPECIFICATION Dyeing installation for textile materials The present invention relates to an installation for dyeing and a method of dyeing associated therewith.

The installation and the method relate to the dyeing of textile materials in the form of fibres.

This type of installation generally comprises a main vat in which one places the material to be dyed and into which the colouring agents and auxiliary products as well as water are injected.

These products are located in secondary vats possibly comprising dosing arrangements and are supplied to the main vat through the intermediary of pipes and valves.

In certain existing installations, the main vat and the secondary vats are located at the same level. This arrangement of the vats makes it necessary to use at least one pump for injecting the colouring agents or auxiliary products into the main vat.

In another type of installation, the secondary vats are located above the main vat and the various products are introduced by gravity into the main vat.

These installations have serious drawbacks. In fact, there was no provision for rinsing the supply circuit when the main vat was under pressure after or before the injection of a colouring agent or of an auxiliary product. Consequently, a certain quantity of product may remain on the walls of the pipework, which impairs dosing of the product at the time of subsequent dyeing. In addition, after the injection of a colouring agent or an auxiliary product into the main vat, a certain quantity of this liquid remains in the supply pipes and mixes with the following colouring agent or auxiliary product which is injected into the main vat. This constitutes a serious drawback if the two products are incompatible in the raw state, before they are diluted in the main vat.This mixing phenomenon is much more troublesome when the vat for the second product is located between the main vat and the vat for the first product. In fact, it is thus impossible to inject all the first product into the main vat, since the quantity of this first product which is located in the supply pipes between the two secondary vats is forced back owing to the injection of the second product into the main vat.

Another drawback of these types of installations is that air may penetrate the main vat.

This air may cause dyeing faults in the material to be dyed, which clearly impairs the quality of dyeing. Air may penetrate the main vat with the colouring agents or auxiliary products if the valve controlling a vat is closed after this vat has been completely emptied, which connects the supply pipes for the main vat to the open air. The air may also be in an emulsion for example in the colouring agents owing to mixing of these products in their vat by means of stirrers. Air bubbles may thus form either in the dosing arrangements or in the supply pipes for the main vat.

In the case where the various dyeing products are injected into the main vat simply by gravity, it is not possible to keep the inside of the main vat under pressure. This pressurisation is important, since it accelerates the dyeing process. In this case, it is necessary to depressurise the vat when each product is injected, which clearly causes a considerable loss of time and a high cost price.

The present invention intends to remedy these drawbacks by proposing a dyeing installation and method, in which there is provision for rinsing the general pipework supplying the main vat after the injection of a product and for purging the air contained in this pipework.

In addition, throughout the stage of filling the main vat with the various dyeing products, this vat will remain under pressure. This represents a saving of time and considerable cost price.

To this end, the installation for dyeing textile materials in the form of fibres or filaments is characterised by the fact that it comprises means which make it possible to rinse the general supply pipework connecting the main vat and the secondary vats and for purging air from the latter.

The dyeing method is characterised by the fact that the supply pipework and the secondary vats are rinsed after injection into the main vat of the dyeing products or auxiliary products and that water is injected in a counter-flow in order to degasify the general supply pipework for the main vat.

The invention will be better understood on referring to the ensuing description and to the single figure which forms an integral part of the description. This figure is a diagrammatic illustration of a dyeing installation according to the invention.

The dyeing installation and method make it possible to dye all textile materials for example cotton, polyester, wool, polyamide in all forms and for example in the state of fibres or filaments.

The installation comprises a main vat 1 or dyeing vat in which the material to be dyed is placed, in this case in the form of spools. It also comprises secondary vats of which there are two types 2 and 4. The first type of vat 2 contains colouring agents. Located below the vats is a dosing arrangement 3 which makes it possible to dose the quantity of colouring agents. The other type of vat 4 contains auxiliary dyeing products.

For example, these products make it possible to fix the dye on the spools or to rinse the fixed dye.

Other products may be used for softening the fibres or making them more supple.

Each of the secondary vats is connected by a system of valves to the general supply pipework 14. This pipework leaves the main vat and terminates beyond all the secondary vats in a valve 38, an output 39 and a flow rate controller 49 providing information relating to the circulation of water in the pipework 14 and controlling a timing mechanism determining the rinsing time.

The products to be dyed are placed in the form of spools in the main vat 1 and water, colouring agents and auxiliary products are injected.

In this vat of known type, the reference numeral 6 designates a plate comprising spindles 7 on which the spools of textile fibres to be dyed are placed. A heating device 9 makes it possible to keep the inside of the main vat at the desired temperature. Below the vat, a stirring device 10 is provided for ensuring the circulation of liquid through the material in the main vat.

This liquid is introduced through the opening 11. The vat is thus supplied with hot water at a temperature of between 30 and 80 by means of the supply 12 and valve 13. It is supplied with dye through the intermediary of the pipe 14 and valve 15. In a preferred embodiment, a non-return valve 1 6 is provided for isolating the supply circuit for dye from the remainder of the installation.

According to a known dyeing method, the main vat may be filled at two different levels: a lower level 17 at which the material 8 is not immersed, or a level 18 at which the material is immersed.

These two levels are controlled by known devices such as 1 9 and 20.

The vat is emptied through the opening 11, the pipe 22 and the valve 21. A supply 23 of compressed gas is connected to the top 24 of the vat. The compressed gas is used for pressurising the vat during dyeing operations. A device comprising pipes 25 and valves 26 and 27 is also provided for depressurising the main vat.

Located above the upper level of the main vat are secondary vats 2 containing colouring agents as well as the corresponding dosing arrangements 3. A stirrer 28 is immersed in the vat 2 for homogenizing the dye.

The vat 2 and dosing arrangement 3 are connected by a valve 29 which controls the link of the dosing arrangement. The valve 30 connects the dosing arrangement and the general supply pipework for the main vat and controls the injection or colouring agent dosed to the main vat.

At its top, the dosing arrangement comprises a pipe 32 and a valve 31 making it possible to degasify the latter as it is filled. A pipe 33 connected to the lower part of the dosing arrangement as well as a valve 34 make it possible to empty the dosing arrangement, for example when rising the dosing arrangement alone.

Also connected to the general supply pipework are the secondary vats 4 containing auxiliary dyeing products. The introduction of auxiliary products to the general supply pipework is controlled by valves 35. These vats also comprise a pipe 36 and a valve 37 making it possible to empty them.

The general supply pipework terminates above the level of the valves 35 by a connection 39 to the open air as well as a valve 38. The purpose of these two parts is to make it possible for the air which has entered the pipework to be purged therefrom. The valve 38 may be of a conventional type or a butterfly type, so that only air is allowed to pass.

A pump 5 located in the general supply pipe between the secondary vats and the main vat controls the injection of a colouring agent or auxiliary product to the main vat. Water is injected under pressure with a counterflow from the lower part into the upper part of the general supply pipe.

This water comes from the supply 40 which is a hot water supply and its admission to the general supply pipe is controlled by the valve 41. In addition, it is connected to this pipe between the pump 5 and the valve 1 5.

This external supply of water also makes it possible to reprime the pump between different operations for injecting the product, or rinsing operations.

Another external hot water supply 42 makes it possible to rinse the secondary vats as well as the general supply pipe. For the vats containing dye stuffs, various methods of rinsing are possible. In itself, the vat may be rinsed by means of the pipe 46 and the valve 43 through its top, or by means of the pipe 47 and valve 44. The latter device makes it possible to spray the walls of the vat in order to dilute the colouring agent which may have remained due to capillarity. As for the dosing arrangement, the latter may be rinsed by means of the pipe 48 and the valve 45.

The vats containing the auxiliary dyeing products are rinsed by means of the device 50 and valve 49. This device also supplies water to the walls of the vat in order to eliminate any product which could have remained on these walls.

Naturally, the device 11 fulfilling the main vat as well as its emptying device, the stirrers, the devices for emptying the secondary vats and the dosing arrangements could be different without diverging from the scope of the invention.

Similarly, the number of vats containing colouring agents as well as the number of vats containing auxiliary products may vary without diverging from the scope of the invention.

When carrying out the method according to the invention the spools of textile material to be dyed are placed in the main vat. Then, water is injected by means of the pipe 12 and valve 13 and the vat is filled up to the chosen level. The soaking time and heating temperature are adjusted to the desired value. The main vat is pressurised by means of the compressed gas inlet 23. The vat will remain under pressure throughout all the various operations of injecting colouring agent or auxiliary product. This represents a considerable saving of time and money with respect to an installation in which the vat has to be depressurised before injecting a product.

The product for injecting an auxiliary dyeing product to the main vat is as follows: the valve 1 5 which is located on the general supply pipe is closed. The valve 35 of the secondary vat which contains the product which one wishes to inject is opened The pump 5 is set in operation in the direction of circulation from the secondary vats to the main vat. The valve 1 5 is then opened to facilitate the injection of product to the main vat.

When the product reaches the minimum level in the secondary vat 4, the valve 35 is closed and the pump 5 is stopped. If rinsing is necessary, the external hot water supply 42 is brought into operation in order to spray water on to the walls of the vat 4 by means of the device 50 and valve 49 which is open. When the walls of the vat have been rinsed sufficiently, the valve 35 is re-opened and the pump 5 is re-started. Thus all the product which remained in the vat 4 and which has been diluted in water is re-injected into the main vat, which removes the latter from the vat and general supply pipe.

When this second injection is terminated, the valves 1 5 and 35 are closed and the pump 5 is stopped. It is thus possible to rinse the vat completely by means of the pipe 50 and its emptying device comprising the pipe 36 and valve 37.

After the injection of an auxiliary product into the main vat, a small quantity of this product may still remain in the diluted state in the general supply pipe. It is possible to rinse this pipe completely in order to remove any trace of this product. To do this, the external water supply 40 is brought into operation and the valve 41 is opened.

The valve 38 is opened. In this way, any trace of product which had been injected into the main vat is removed completely from the general supply pipe.

It is also very important that the auxiliary products injected are deaerated. In fact, if an air bubble penetrates the main vat with the product, this may cause differences in the shades of dye.

This air may be in the form of an emulsion in the product at the time of its injection or also may penetrate the general supply pipe owing to the fact that a vat has been emptied too much. In this case, an air buffer forms in the pipe. Owing to the fact that the secondary vats are located above the upper level of the main vat, air will tend to rise to the top of the installation, i.e. to the valve 38 and outlet 39. Thus, by the same method which makes it possible to rinse the general supply pipe completely, by injecting water with a counterflow, it is possible to degasify this pipe by expelling air through the valve 38.

The process for the injection of a colouring agent into the main vat is slightly different from that for an auxiliary product. As in the preceding case, the valve 1 5 is closed and the pump is stopped. The valves 29 and 30 are also closed.

The valve 29 is opened and the product descents from the vat 2 to the dosing arrangement 3 by gravity. The valve 31 is also opened in order to allow the air trapped in the dosing arrangement to escape. The valve 31 and pipe 32 also make it possible to degasify the dosing arrangement.

When dosing is terminated, the valve 29 is closed and the valve 30 is opened. The pump 5 is set in operation in the normal direction of circulation, i.e. from the secondary vats to the main vat and the valve 1 5 is opened. The colouring agent dosed in thus injected into the main vat.

When the injection is terminated, the valve 1 5 is closed, the pump 5 is stopped and the valve 30 is also closed. One thus proceeds with rinsing of the dosing arrangement.

The external water supply 42 is set in operation and the valve 45 is opened. Water is thus introduced into the dosing arrangement in order to rinse the walls. When rinsing is terminated, the valve 45 is closed, the valve 30 is opened, the pump 5 is re-started and the valve 15 is reopened. The remainder of the dilute colouring agent is re-injected into the main vat. When this re-injection is terminated, the valves 1 5 and 30 are closed and the pump-is stopped.

As in the case of an auxiliary product, complete rinsing of the general supply pipework is also possible by means of the external water supply 40 and the valves 41 and 38.

By this same method, it is also possible to eliminate from the general supply pipework, air bubbles which may have been introduced during the injection.

For a colouring agent, as for an auxiliary product, rinsing the dosing arrangement 3 or vats 4 with water, then reinjecting rinsing water with the diluted product into the main vat improves the quality of dosing of the various products and thus the dyeing. In fact, there is no loss of product due to capillarity on the walls of the dosing arrangements of the vats or of the pipes.

The external water supply 40 which makes it possible to purge the general supply pipe or to rinse the latter completely, also makes it possible to reprime the pump 5. To do this, the valve 1 5 is closed, the valve 41 is opened and as for the purge, water is injected into the circuit. This supply of water thus prevents specific repriming supplies for the pump and makes it possible to reprime the latter rapidly in the case of need.

Claims (15)

1. Dyeing installation for textile materials in the form of fibres, comprising a main dyeing vat and a plurality of secondary vats containing dyeing agents and auxiliary products, these various vats being connected on the one hand to external supplies of fluid, steam, air and on the other hand interconnected by means of a single general pipe for supplying colouring agents and auxiliary products, characterised by the fact that it comprises means making it possible to rinse this general supply pipe and to purge air from the latter.

2. Dyeing installation according to claim 1, characterised by the fact that the vats containing colouring agents and auxiliary products and the pipes connecting these vats to the main vat are located above the level of the main vat.

3. Dyeing installation according to claim 1, characterised by the fact that for rinsing each secondary vat and the general supply pipe, it comprises an external water supply.

4. Dyeing installation according to claim 1, characterised by the fact that it comprises a valve making it possible to purge air, located at the end of the general supply pipe beyond the last secondary vat.

5. Dyeing installation according to claim 1, characterised by the fact that for purging air from the general supply pipe, it comprises an external supply of water circulating with a counterflow from the main vat to the secondary vats.

6. Dyeing installation according to one of claims 3 or 5, characterised by the fact that the water is previously heated to a temperature of between 30 and 80 .

7. Dyeing installation according to claims 5 and 6, characterised by the fact that the supply of water for purging is connected to the general supply pipe between the main vat and the pump.

8. Dyeing installation according to claim 5 and 7, characterised by the fact that the supply of water for purging air makes it possible to reprime the pump.

9. Dyeing installation according to claim 1, characterised by the fact that the dosing arrangements for the secondary vats comprise at their top, a pipe making it possible to degasify the latter.

10. Method for dyeing textile materials in the form of fibres, characterised by the fact that the general supply pipe, the dosing arrangements, the vats containing the colouring agents and the vats containing the auxiliary products are rinsed after the injection to the main vat of dyeing agents or auxiliary products and that water is injected with a counterflow for degasifying the general supply pipe to the main vat.

11. Method of dyeing according to claims 3 and 10, characterised by the fact that the water used for rinsing the dosing arrangements or secondary vats is injected into the main vat.

12. Method of dyeing according to claims 4, 5, 7 and 10, characterised by the fact that water is injected with a counterflow by means of an external supply and the pump in order to purge air from the general supply pipe.

13. Method of dyeing according to one of claims 10 to 12, characterised by the fact that the main vat is kept under pressure during the operations for injecting the rinsing products and for purging.

14. A dyeing installation substantially as hereinbefore described with reference to the accompanying drawing.

15. A method of dyeing substantially as hereinbefore described with reference to the accompanying drawing.