WO2022229759A1

WO2022229759A1 - Plant for the environmentally sustainable dyeing of spooled yarn and similar textile products, textile staple fibres and various articles with indigo and other reducing dyes

Info

Publication number: WO2022229759A1
Application number: PCT/IB2022/053318
Authority: WO
Inventors: Francesco Ronchi
Original assignee: Master SRL
Current assignee: Master SRL
Priority date: 2021-04-29
Filing date: 2022-04-08
Publication date: 2022-11-03
Anticipated expiration: 2023-10-29
Also published as: IT202100010871A1

Abstract

A plant for dyeing textile material is described, comprising a dyeing apparatus enclosing a dyeing compartment, a material-holder frame contained in the dyeing compartment, at least one tank containing a dye bath, a hydraulic supply circuit to supply the dye bath to the dyeing com¬ partment, a hydraulic return circuit to reintroduce the dye bath leaving the dyeing compartment into the tank, and a plurality of material-holder devices supporting the textile material, mounted on the material-holder frame. The dye bath is dynamically dispensed through the textile material in one direction, under pressure and in one direction from inside to outside the textile material. The dyeing compartment is provided with means to collect the dye bath which passed through the textile material and to reintroduce it into the tank via the hydraulic return circuit. The dyeing plant further comprises a vacuum tank which extracts the dye bath from the textile material present in the dyeing compartment by vacuum suction and holds the vacuum-extracted dye bath in it and then sends it to the tank containing the dye bath. The dyeing compartment and the tank contain an inert gas in addition to the dye bath.

Description

PLANT FOR THE ENVIRONMENTALLY SUS¬

TAINABLE DYEING OF SPOOLED YARN AND SIMILAR TEXTILE PRODUCTS, TEXTILE STAPLE FIBRES AND VARIOUS ARTICLES WITH INDIGO AND OTHER REDUCING

DYES

[0001] The present invention relates to a plant and a process for dyeing textile materials such as yams in spools, beams, flocks, textile staple fibres, in “tops” (discontinuous fibre slivers) and “tow” (bundles of parallel and continuous filaments), ready-made garments, etc., with indigo and other reducing dyes, in a short bath and in an inert en vironment. For the sake of clarity and explanatory simplicity, the dyeing plant according to the present invention will be described by way of example but without limitation, with reference to the dyeing of spooled yarn with indigo dye only.

[0002] When analysing the yarn dyeing sector in general, it is clear that cross-spool dyeing has become increasingly popular over the last fifty years because of its many economic and technical advantages. Continuous improvements in all the various areas of machinery construction, in particular winding machines, have contributed significantly to this success.

[0003] Modern spooled yam dyeing plants are typically made of chemical-resistant stainless steel, operate under static pressure up to a maximum temperature of 140°C and are therefore also suitable for dyeing synthetic fibres. These dyeing plants are equipped with sophisticated control and monitoring devices, increasingly improved dye bath cir culation pumps and all necessary treatments are carried out with continuously updated processes and products. Basically, these dyeing plants consist of a cylindrical boiler with a cylindrical bottom and cover, the latter being lockable with a bayonet locking system and tiltable by means of a counterweight or pneumatic piston. Each dyeing plant is equipped with a centrifugal pump for forced circulation of the dye bath, bidi rectionally through the spools, and with a heat exchange system for heating or cooling the bath. These dyeing plants are normally equipped with various accessories, such as a pump for creating static pressure, an open vessel for dye bath expansion and also to allow the introduction of ingredients, a small pressurised boiler for sampling a single spool, etc. The heat exchange system of these dyeing plants consists of a large internal coil placed at the bottom of the boiler, in the space between the bottom itself and the base supporting the material-holder devices, that is the devices which support the textile material to be dyed. [0004] In the specific technical sector, these dyeing plants can be considered to be of universal utility as they are constructed with boilers that can have a variety of diameters and heights to allow different yarn capacities, ranging from a few kilograms to over one thousand kilograms, to be treated. Indicatively, these dyeing plants are dis tinguished on the basis of two construction versions, that is dyeing plants with a “low” boiler, with single deck yam carriers, for small and medium capacities, and dyeing plants with a “high” boiler, with double deck yam carriers, for medium and large ca pacities and for special assemblies such as warp beams, etc. These dyeing plants operate on average with a dye bath ratio of about 1/10, that is they use 10 litres of water per kilogram of textile material treated, for a variable number of water changes. The number of water changes in a dyeing cycle naturally varies according to the type of textile material being treated and the specific class of dye used. This number of water changes can be quantified from a minimum of two to a maximum of ten, most of which are made in hot baths and therefore with great consumption of not only water but also thermal energy. If we take into account the ecological problems and those relating to the general shortage of now precious water and energy sources, it is clear that the dyeing industry needs to have machinery which, above all, drastically reduces this consumption and avoids all forms of atmospheric and environmental pollution.

[0005] A first technical solution to this problem is disclosed in patent document

FR 2253865 Al, which describes a dyeing plant wherein the yam is no longer immersed in the dye bath, in contrast to conventional full volume dyeing plants with the yarn totally immersed and with reversal of the direction of bath circulation, which alternately passes through the various spools from inside to outside and vice versa. Consequently, the dye bath is drastically reduced in volume and circulated through the various spools in only one direction, that is from the inside to the outside only. In its construction this dyeing plant is almost identical to those according to the prior art, from which it differs substantially in that the lower part of the boiler, that is the area between the convex bottom of the boiler and the support for the material-holder devices, has been considerably lengthened so as also to contain the quantity of bath necessary for dyeing and circulation, which has become unidirectional, in addition to the large coil for thermoregulation. As a consequence of the above, the static pres- surisation of the boiler, which is necessary in order to be able to operate above 100°C and avoid cavitation of the circulating pump, has changed from a dyeing plant full- volume hydraulic system to a pneumatic system operating through the introduction of compressed air or other gas.

[0006] Patent document US 3775055 A discloses a plant that not only dyes various textile materials, but also performs a diverse range of multiple treatments on those textile materials with various chemicals. The plant basically consists of two separate connected tanks, built to withstand a particular internal pressure as well as maximum vacuum. A vacuum is created in the lower tank by means of a pneumatic pump, so as to remove air from the textile materials contained within it and ensure that the dye bath present in the upper tank and pressurised with compressed air and/or steam can quickly spray and evenly distribute itself throughout the thickness of the textile materials being treated when drawn back into the lower tank under vacuum. However, this plant cannot be used to dye with indigo dye, as it is impossible to carry out the sequential operating cycle required by indigo dye (i.e., impregnation, wringing and oxidation, repeated several times) directly within the plant.

[0007] In practice, it can be stated that, irrespective of differences in construction and management, all spooled yarn dyeing plants in use today, in the two different systems described above, are suitable for dyeing yarns of all textile fibres with their specific classes of dyes, with results of excellent quality, with the exception of dyeing with indigo dye. This is because indigo is an ancient natural dye which, although it has been produced by synthesis for over a century, still requires a characteristic and special operating procedure for its application. In fact, for application to such fibres, indigo dye, having a relatively small molecule and a low affinity for cellulose fibres, not only requires chemical reduction in an alkaline solution (in leuco form), but also several im pregnations in between wringing and subsequent oxidation in air. To obtain a medium or dark blue colour it is necessary to subject the yam to a first dyeing operation consisting of impregnation phases (normally carried out at 25-40°C), wringing and oxidation, immediately followed by several over-dyeing operations, the more the darker the tones and the higher the colour fastness required.

[0008] The conventional dyeing process just mentioned has always been carried out in all the machines and continuous yam dyeing plants for the warps of denim fabrics for the production of jeans, the trousers that from humble workwear have become synonymous with leisure time to the point that they have risen to the splendour of high fashion and have become a worldwide clothing classic. This is because indigo is the only dye with the special feature that, over time, following multiple washes, the original colour tone of the jeans becomes ever lighter but much brighter and therefore extremely attractive.

[0009] In the wake of the success of the inimitable jeans, in these times of economic crisis the fashion industry is increasingly calling for indigo-dyed cotton yarn and sees the possibility of significantly expanding the range of new products that will enliven the relevant markets. The availability of environmentally friendly and economical yams, cotton in particular, dyed with indigo which is especially well fixed to the fibre and ad vantageous even in the most standardised and industrially widespread form, that is in spools, is of great interest because of the possibility of producing a wide range of new types of fabrics and knits. As well as sweatshirts and sportswear, there is also the pos sibility of offering jeans with a new final look, made from a new ecological denim and also by knitting, which are in great demand as they are more comfortable and fit better than the traditional ones. Similarly, the possibility of dyeing various textile fibres with indigo directly in the staple is also in demand, as it is very interesting economically and ecologically, while maintaining the quality characteristics mentioned above. This method of dyeing would allow spinning companies to produce a wide range of in novative yarns with a variety of performance characteristics, with which it would be possible to create new and original-looking articles. This method of dyeing could even revolutionise the traditional production system for denim, the classic jeans fabric and the most widely produced fabric in the world, the warp yarns of which are dyed with indigo on long, complex, expensive and time-consuming continuous dyeing lines. The availability of dyed yarn could in fact eliminate the traditional continuous dyeing process mentioned above, simplifying operations, with considerable savings in the con sumption of water, chemicals and energy. In addition, in view of the wide range of conventional, specific and core-spun yarn types obtainable from spinning, the variables in the fabrics that can be produced would also be very much enlarged, and this would enable many garments of novel and unparalleled appearance to be obtained, in addition to the traditional final effects.

[0010] Unfortunately, while the traditional dyeing process mentioned above was easily applied to continuous dyeing lines for warp yarns, which consist of a sequence of dyeing tanks each equipped with squeezing and oxidation devices, the same dyeing process is not as easy, or rather is very difficult to apply, in traditional discontinuous dyeing plants operating in “batch” mode, with spooled and similarly arranged yarns. This is due to specific structural difficulties and the need to carry out many manual op erations in these batch dyeing plants, with consequent very high costs and above all with less than optimum quality results. In fact, in batch dyeing plants, in order to dye with indigo using the traditional dyeing process, which involves several successive stages of impregnating the yarn with leuco, eliminating the excess dye bath present in the dyed yam and its oxidation, after the first dyeing it would be necessary to remove the spools from the dyeing plant, hydro-extract them and then oxidise the dye by blowing compressed air. The spools would then have to be reintroduced into the dyeing plant to repeat all the steps (dyeing, hydro-extraction, oxidation) again and again until the desired colour tone was achieved. This clearly demonstrates that in these batch dyeing plants it is in practice impossible to dye spools with indigo, except by performing a single dyeing step, without intermediate hydro-extraction and with chemical oxidation. Chemical oxidation is, moreover, a delicate operation, as it is liable to uncontrolled reactions and prevents the dye bath from being recovered for re- use. In short, it is a method of dyeing that can only be used for light tones, and in any case with less than optimum quality results.

[0011] The object of the present invention is therefore to provide a plant for the environ mentally sustainable dyeing of spooled yams or similar textile products, textile staple fibres and various articles with indigo and other reducing dyes, which is capable of overcoming the above-mentioned drawbacks of the prior art in an extremely simple, economical, ergonomic, ecological and particularly functional manner.

[0012] In detail, it is one object of the present invention to provide a plant for dyeing with indigo and other reducing dyes which enables the whole traditional dyeing cycle to be performed in a sequential way (dyeing, hydro-extraction, oxidation), directly inside the plant and in an inert environment, preferably under nitrogen, in order to obtain a number of advantages which are not only managerial and economic, but above all qualitative in terms of colour tone, fixation and solidity of the dye and brilliance of the dyeing process.

[0013] Another object of the present invention is to provide a plant for dyeing with indigo and other reducing dyes which, in an inert environment and preferably under nitrogen, is able to operate with the smallest possible quantity of dye bath, so as to significantly reduce the consumption of energy, water and chemical products (caustic soda, sodium hydrosulphite, etc.) and, consequently, reduce production costs.

[0014] A further object of the present invention is to provide a plant for dyeing with indigo and other reducing dyes which, in an inert environment and preferably under nitrogen, can operate without the spooled yarns being immersed in the dye bath, which is instead only fed in one direction from the inside to the outside of the spools themselves.

[0015] A further object of the present invention is to provide a plant for dyeing with indigo and other reducing dyes, in an inert environment and preferably under nitrogen, wherein the dye bath is never permanently present in the boiler of the dyeing plant, but only in the tank for preparation/circulation and storage of the dye bath itself in the various operating stages, always in a minimum relation to the weight of the yam, even in case of partial loads.

[0016] A further object of the present invention is to provide a plant for dyeing with indigo and other reducing dyes which, in an inert environment and preferably under nitrogen, enables the number of dyeing steps to be reduced to one.

[0017] A further object of the present invention is to provide a plant for dyeing with indigo and other reducing dyes which, in an inert environment and preferably under nitrogen, enables exclusive dyeing cycles with dye baths to be carried out at temperatures above the standard temperature for continuous, high concentration and also low temperature dyeing lines.

[0018] A further object of the present invention is to provide a plant for dyeing with indigo and other reducing dyes which, in an inert environment and preferably under nitrogen, allows the spent dye baths to be recovered in such a way that, after the various components have been measured and supplemented, these dye baths can be reused.

[0019] A further object of the present invention is to provide a plant for dyeing with indigo and other reducing dyes, which, by using the minimum possible volume of dye bath, makes it economical to apply a system to cool the dye bath itself to around 15°C, the characteristic temperature at which indigo has the highest affinity with the textile fibre, in order to further increase dyeing performance.

[0020] A further object of the present invention is to provide a dyeing plant for dyeing with indigo and other reducing dyes which is particularly suitable for producing fabrics and knitwear for jeans, sweatshirts and sportswear, etc.

[0021] These objects according to the present invention are accomplished through providing a plant for dyeing yams in spools and similar textile products with indigo and other reducing dyes as set forth in claim 1.

[0022] Further features of the invention are disclosed by the dependent claims, which are an integral part of this description.

[0023] The dyeing plant for dyeing yarns in spools and similar textile products according to the present invention with indigo and other reducing dyes does not present any of the problems typical of dyeing plant of the known type. In particular, compared to the dyeing plant illustrated in patent document FR 2253865 Al, the dyeing plant according to the present invention has in common only the fact that the yarn is not immersed in the dye bath and that this dye bath circulates in one direction. For the rest, the dyeing plant according to the present invention is conceptually different, original, complete, rational and specifically designed to operate with the particular operating method required by indigo dye, in an environmentally sustainable manner. In fact, the dif ferences in construction and function of the dyeing plant according to the present invention are many and substantial, both with respect to the traditional ones, and with respect to the one illustrated in patent document FR 2253865 Al, differences that make it unique.

[0024] In detail, while all the dyeing plants for dyeing spooled yams of the known type, either operating at full volume or operating with reduced bath volume such as the one illustrated in patent document FR 2253865 Al, are operationally united by the presence of the dye bath in the respective boilers, where this dye bath is also usually prepared and procedurally thermoregulated, the dyeing plant according to the present invention totally differs from the prior art in the particular and original constructional form of its dyeing apparatus, which replaces the boiler of traditional dyeing plant such as, for example, the one illustrated in patent document FR 2253865 Al. This dyeing apparatus is characterised in that it always operates in the total absence of the dye bath, which is a basic condition for the special operating process required by indigo dye.

[0025] Another difference is that in the dyeing plant according to the present invention the circulating dye bath is contained in an external, hermetically sealed tank. This external tank contains the dye bath only in the necessary quantities, even for partial loads, but always in a constant ratio to the weight of the yarn or other textile material being treated. For these necessary variations in level the tank does not have thermoregulation coils inside, but these are fitted outside, on the bottom and on the wall, and can be used independently, with the advantage that incrustations of dye can also be avoided, in addition to facilitating cleaning and maintenance. In this multi-functional vessel, preferably operating under nitrogen, the dye bath is not only prepared, but also ther- moregulated, circulated, stored during the various operating phases carried out without bath circulation and replenished from the volume aspirated in the intermediate phases of hydro-extraction of the yam or other textile material by vacuum suction.

[0026] In addition, the particular form of operation of the dyeing plant according to the present invention is ensured by being provided with a large tank for hydro-extraction of the yarn under nitrogen by means of vacuum suction, with retention of the aspirated bath and its subsequent delivery to the circulation vessel. This device is essential for effecting intermediate and final hydro-extraction of the textile material being processed, in an inert environment and directly inside the dyeing apparatus, as well in addition to final oxidation of the dye after de-inertization of the dyeing apparatus and opening an air inlet.

[0027] It is pointed out that the vacuum suction provided in the dyeing plant illustrated in patent document FR 2253865 A1 only has the possible function of deaerating the spooled yarns before the dye bath is introduced, in order to facilitate bath/fibre contact, and not hydro-extraction. The introduction of compressed air (or “favourably” nitrogen) into the dyeing plant illustrated in patent document FR 2253865 Al, outside the spooled yarns, is instead intended to pressurise the dyeing plant itself in the sole case of dyeing above 100°C, so much so that this injection of compressed air is controlled by a pressure gauge, as shown in figures 1 and 2 of FR 2253865 Al. On the contrary, in the dyeing plant according to the present invention there is no provision for the supply of compressed air, but if it were in any case supplied from inside the spools it could serve for final oxidation of the dye and not for its pressurisation. The nitrogen is not introduced into all the surrounding apparatus, in contact with the dye bath and yam, under pressure, but in a regulated and controlled manner by a residual oxygen analyser, in the quantity necessary to maintain a constant pre-set percentage. Constant maintenance of the pre-set residual oxygen percentage is fundamental as it is an important parameter in indigo dyeing and any variation in it has a significant influence on the final results in terms of colour tone, surface adhesion, fixation, etc. [0028] Another difference with respect to the prior art is that the dyeing apparatus of the dyeing plant according to the present invention operates at atmospheric pressure and is therefore of very simple and economical construction, as well as dispensing with prior construction approval, testing and periodic inspection by bodies responsible for the safety of plants operating under pressure at high temperatures. In practice, for dyeing with indigo and other reducing dyes, in an inert environment and preferably under nitrogen, without immersion of the spooled yams in the dye bath (which is therefore of reduced volume), the dyeing plant according to the present invention is the only one which is able to perform not only the entire characteristic operating cycle required by indigo dye (i.e. impregnation, wringing and oxidation, repeated several times) directly within it and without movement of the textile material, but also other dyeing with an innovative, single -phase and/or repeatable process, without intermediate oxidation, as well as special single operating cycles with dye baths at temperatures above the standard temperature for continuous, high concentration and low temperature dyeing lines. All this in a very short time and in an environmentally sustainable way.

[0029] The features and advantages of a plant for dyeing yams in spools and similar textile products with indigo and other reducing dyes according to the present invention will be more apparent from the following description, which is illustrative and not limiting, which refers to the attached schematical drawings wherein:

[0030] Figure 1 is a schematical view, in vertical longitudinal cross-section, of a first em bodiment of a plant for dyeing textile material, in particular spooled yams, according to the present invention, in the version for single batches of yams and arranged in particular for dyeing with indigo in an inert environment, wherein the spools are arranged vertically superimposed on each other, positioned on respective conventional movable material-holder devices, which may be single or superimposed multiple decks;

[0031] Figure 2 is a schematical view, in vertical longitudinal cross-section, of a second em bodiment of a plant for dyeing textile materials, in particular spooled yarns, according to the present invention, in the version for large batches of yarns, to be dyed in various batches, and therefore provided with an additional tank for the single preparation of all the dye bath required for the whole batch, which is an essential condition to ensure the final uniformity of single batches;

[0032] Figure 3 is a schematical view, in vertical longitudinal cross-section, of the single deck dyeing apparatus of the dyeing plant in Figures 1 and 2, wherein this dyeing apparatus is arranged for the specific dyeing of textile staple fibre cakes, which can be positioned and moved on base decks;

[0033] Figure 4 is a schematical view, in vertical longitudinal cross-section, of only the dyeing apparatus of the dyeing plant in Figures 1 and 2, wherein this dyeing apparatus is arranged for the specific dyeing of spooled yams arranged radially on a specific ring material-holder device, of the type illustrated in patent document EP 0034390 B 1 in the name of the same applicant;

[0034] Figures 5A to 5F show, in vertical longitudinal cross-section, respective possible spools of treatable textile fibres, manufactured articles and variously spooled yarns po sitioned on conventional material-holder devices of the single-deck type and specifically: for yams in tapering or cylindrical spools (Figure 5A), for yams in tapering or cylindrical spools and with a buffer vessel for reducing the volume of inerting agent (Figure 5B), for yarns in cakes, slivers, etc. (Figure 5C), for yarns in tops, tow, etc., (Figure 5D), for slivers, zips, etc., (Figure 5E) and with a material- holder device of the hopper type for bundle loading of textile staple fibres, hank yams, manufactured articles, ready-made garments, etc., and with a central buffer vessel for reducing the capacity and volume of the dye bath and/or the quantity of inerting agent (Figure 5F); it should be noted that these possibilities are also valid for the equivalent material-holder devices without walls, so-called flat or cake type, referred to in Figure 3; and

[0035] Figures 6A to 6G show, in vertical longitudinal cross-section, respective possible spools of yam, textile fibres, manufactured articles and ready-made garments which can be treated, positioned on traditional material-holder devices of the two-deck type and specifically: for yarns in tapering or cylindrical spools (Figure 6A), for yarns in tapering or cylindrical spools and with a buffer vessel for halving the volume of inerting agent (Figure 6B), for yarn beams for warps, for fabrics, etc., whose height makes it necessary for them to be inserted into the dying apparatus of two-deck material-holder devices (Figure 6C), for yarns in cakes, slivers, etc., (Figure 6D), per fibres in tops, tow, etc., (Figure 6E), for slivers, zips, etc. (Figure 6F) and with material-holder devices of the hopper type for bundle loading of textile staple fibres, hank yarns, manufactured articles, ready-made garments, etc., and with a central buffer vessel for reducing the capacity and volume of the dye bath and/or the quantity of inerting agent (Figure 6G); it should be noted that these possibilities are also valid for the equivalent material-holder devices without walls, the so-called flat or doughnut type, mentioned in Figure 3.

[0036] It should be noted that the material-holder devices shown in Figures 3 and 4 can be centrifuged in special hydroextractors, an operation which, limited to a few separate operating cycles, could allow the vacuum suction vessel to be incorporated and/or replaced. As regards spooled yams only, it should be noted that these traditional material-holder devices, which are well known in the state of the art, normally consist of one or two base plates. Each base plate is hollow and carries a series of vertical rods, arranged interspaced on concentric circles, on each of which the spooled yarns are threaded one on top of the other, forming a stack which is blocked at the top by a cap. The choice of the first and/or second construction version is determined by the need to have the different production quantities required by various specific sectors of use.

[0037] It should also be pointed out that the following description and attached figures do not illustrate numerous components, accessories and instrumentation normally supplied with all dyeing plant, such as, for example, dye bath level regulators, ther moregulation units, tanks for preparation, recovery of dye baths and supply of auxiliary products, automatic metering systems, control and monitoring instruments, etc., since they are well known to those skilled in the art. It should also be noted that the attached figures illustrate hydraulic circuits equipped with respective pumps and valves which will not be described in detail below, as they are also well known to those skilled in the art.

[0038] With particular reference to Figures 1 and 2, a plant for dyeing textile materials, in particular but not exclusively yam in spools, according to the present invention is shown. The dyeing plant is indicated as a whole by reference numeral 10. The dyeing plant 10 is arranged to carry out the dyeing of textile material S with both indigo and other reducing dyes. Although in Figures 1 and 2 the textile material S consists in particular of spools of yam, the dyeing plant 10 may also be arranged to carry out the dyeing of other textile products, such as, for example, the cakes of textile staple fibres shown in Figure 3, or variously made-up yarns, and others.

[0039] The dyeing plant 10 comprises at least one dyeing apparatus 12. This dyeing apparatus 12 is provided with a casing 14, enclosing at least one dyeing compartment 16, and at least one hermetically sealed closing element 18, which is provided on the casing 14 and which allows access to the dyeing compartment 16. Within the dyeing compartment there is provided at least one material-holder frame 20, which may assume different configurations depending on the type of textile material S, as shown for example in Figure 3, Figure 4 and Figures 5A to 6G.

[0040] Regardless of the configuration of each material-holder frame 20, the dyeing plant 10 further comprises at least one tank 24, 26, which contains a predefined amount of at least one dye bath B. In a first embodiment of the dyeing plant 10, shown in Figure 1, a single tank 24 is provided. In a second embodiment of the dyeing plant 10, shown in Figure 2, there is instead provided at least one second tank 26 in addition to the first tank 24. These tanks 24, 26 will be described in more detail below.

[0041] At least one first hydraulic supply circuit 28 is hydraulically connected to both at least the tank 24 and the dyeing apparatus 12 to feed the dye bath B from the tank 24 to the dyeing compartment 16. At least one second hydraulic return circuit 30 is also hy draulically connected to both at least the tank 24 and the dyeing apparatus 12 to reintroduce into the tank 24 the dye bath B leaving the dyeing compartment 16, as will be further specified below.

[0042] A plurality of material-holder devices 32 is mounted on the material-holder frame 20, preferably in a removable manner, each of which material-holder devices supports and retains a predefined amount of textile material S, such as a plurality of spooled yarns shown in Figures 1 and 2. In this way, the material-holder devices 32 may be inserted into the dyeing compartment 16 and be extracted from said dyeing compartment 16 through the closing element 18, which typically comprises an upper cover.

[0043] Both the material-holder frame 20 and the material-holder devices 32 are internally provided with respective ducts 34, 36 for supplying the dye bath B. These ducts 34, 36, that is the ducts 34 provided in the material-holder frame 20 and the corresponding ducts 36 provided in the material-holder devices 32, are hydraulically connected to the first hydraulic supply circuit 28 to dynamically and unidirectionally dispense the dye bath B through the textile material S, under pressure and in one direction from inside to outside said textile material S, by means of a plurality of dispensing holes 70 (see Figure 3) provided on the material-holder devices 32. Pressure may be supplied to the dye bath B by one or more pumps 82 provided on the first hydraulic supply circuit 28. The dyeing compartment 16 is then provided with collection means 38, hydraulically connected to the second return hydraulic circuit 30, for collecting the dye bath B that has passed through the textile material S, so that the dye bath B leaving the dyeing compartment 16 is reintroduced into the tank 24 via the second return hydraulic circuit 30. Consequently, the dye bath B is always in circulation within the dyeing com partment 16 or, in other words, no accumulation and/or stagnation of dye bath occurs within the dyeing compartment 16.

[0044] The dyeing plant 10 according to the present invention is therefore capable of operating with a very low ratio between the weight of the textile material S and the volume of the dye bath B, indicatively equal to 1/4, compared to a value of about 1/10 for dyeing plants according to the prior art. The dyeing plant 10 according to the present invention is also capable of hydro-extracting and oxidising the textile material S directly within itself once it is impregnated with the dye bath B.

[0045] In fact, the dyeing plant 10 comprises at least one vacuum tank 40, which is hy draulically connected both to the dyeing apparatus 12, via at least one vacuum suction hydraulic circuit 42, and to the tank 24, via at least one make-up hydraulic circuit 44. The vacuum tank 40 may be provided with one or more vacuum pumps 72, arranged to generate a pressure condition of less than atmospheric pressure within the vacuum tank 40 itself. The vacuum tank 40 may also be provided with air supply means 76 that may be used, for example, to restore atmospheric pressure within the vacuum tank 40 itself. The vacuum tank 40 is arranged to carry out, by means of vacuum suction, the ex- traction of the dye bath B from the textile material S contained in the dyeing com partment 16, as well as to keep the vacuum extracted dye bath B inside it and to sub sequently send it to the tank 24 by means of the hydraulic make-up circuit 44. As previously mentioned, the vacuum tank 40 is indispensable for performing the in termediate and final hydro-extractions of the textile material S being processed, in an inert environment and directly inside the dyeing apparatus 12. This vacuum tank 40 is also arranged to oxidise of the dye bath B applied to the textile material S in air at the end of dyeing and by means of air supply means 74 provided on the housing 14 of the dyeing apparatus 12.

[0046] The dyeing plant 10 according to the present invention is also capable of operating in an inert environment: this is a particular and advantageous ecological technology, described in patent documents EP 1771617 B1 and EP 1971713 B1 in the name of the same applicant. For this purpose, both the housing 14 of the dyeing apparatus 12 and the at least one tank 24, 26 are provided with respective means 46, 48, 50 for the supply of an inert gas N within, respectively, the dyeing compartment 16 and the at least one tank 24, 26 and its respective expulsion means 52, 54, 56. Preferably but not exclusively, the dye bath B is an indigo-based dye bath and the inert gas N preferably comprises nitrogen.

[0047] Referring in particular to the embodiment of the dyeing plant 10 in Figure 2, this dyeing plant 10 comprises:

[0048] - a first hermetically sealed tank 24, preferably obtained by means of a re spective closure element 22, for circulating and storing the dye bath B, wherein this first tank 24 contains both the dye bath B and a predefined amount of inert gas N, which is supplied via respective supply means 48; and - at least one second hermetically sealed tank 26, which is hydraulically connected to the first hermetically sealed tank 24, by at least one respective hydraulic connection circuit 58, and which acts as a single total preparation vessel for the dye bath B in the presence of the inert gas N, supplied by re spective supply means 50.

[0049] Both the first hermetically sealed tank 24 and the second hermetically sealed tank 26, when present, may then be provided with respective means 60, 62 for thermoregulation of the dye bath B. Preferably, these thermoregulation means 60, 62 for the dye bath B may comprise coils for circulating a thermoregulation fluid. Even more preferably, these coils may be positioned on respective lower and/or lateral outer portions of at least one of the first hermetically sealed tank 24 and the second hermetically sealed tank 26, as shown in Figures 1 and 2.

[0050] In specific cases of use for dyeing spooled yams arranged radially on material-holder devices 32 in an annular configuration, as well as for dyeing textile staple fibre cakes, the dyeing apparatus 12 may be internally provided with at least one chamber 64 having the function of a buffer vessel for reducing the volume of the inert gas N within the dyeing compartment 16, as shown for example in Figures 3 and 4. Alternatively or additionally, depending on the specific configuration of the material-holder frame 20 and/or the material-holder devices 32, these material-holder devices 32 may be provided with at least one equipment 66 also having the function of a buffer vessel for reducing the capacity and volume of the inert gas N within the dyeing compartment 16.

[0051] The first hydraulic supply circuit 28 may be provided with respective supply means 68 for the inert gas N, and/or recovery means 78 for the spent dye bath B, which is to be sent, for example, to tanks that are external with respect to the dyeing plant 10, and / or discharge means 80 for possible washing fluids. The collection means 38 for the dye bath B, provided in the dyeing compartment 16, may instead comprise at least one collector which is provided in a lower portion of the housing 14.

[0052] According to the above, in order to significantly increase its productivity, the dyeing plant 10 according to the present invention may be used only for the purely dyeing phase in the cycle of processing the textile material S, while the remaining initial op erations (soaking, scouring, pre-dyeing, etc.) and final operations (washing, soaping, softening, over-dyeing, etc.) may also be performed in conventional dyeing plant. The dyeing plant 10 according to the present invention is in fact specifically designed to:

[0053] - operate, in a sequential manner, with spooled yarns or generic textile material

S to be dyed, which are never immersed in the dye bath B, with the advantage of considerably reducing the volume of said dye bath B, with a consequent drastic reduction in its various chemical components, and the consumption of energy and above all water;

- operate in an inert environment, preferably under nitrogen, so that the dye bath B present in the spooled yarns or in the generic textile material S (not immersed in the dye bath B) housed on the material-holder devices 32 does not oxidise in certain operating phases of the dyeing cycle, but continues its diffusion and fixation action in the textile fibre;

- operate with various types of material-holder devices 32, feeding the dye bath B under pressure from the inside to the outside of the spooled yarns or generic textile material S to ensure the best possible interchange between the dye bath B and the textile fibre;

- if necessary, reduce the volume of inert gas N within the dyeing compartment 16 in the case where the capacity is halved, by applying one or more hollow buffer vessels 64, 66, with the advantage of also shortening the time for iner tization;

- also use the same material-holder devices of the traditional dyeing plants, already possessed and used by users of the dyeing plant 10, and/or make them interchangeable for an advantageous operational synergy;

- increase the operational flexibility of the dyeing plant 10 with the possibility of using conventional yarn carriers, smaller in size and capacity than the nominal size and capacity of the dyeing apparatus 12, while maintaining the reduced ratio between dye bath volume and yarn weight.

[0054] In addition to the above-mentioned particular features, the fact of operating in an inert environment, preferably under nitrogen, allows the dyeing plant 10 according to the present invention to update the well-known indigo dyeing operating cycle, which essentially consists of three operating phases that are repeated several times (impregnation of the yam with leuco, elimination of the excess of dye bath contained therein and oxidation of the dyed yam). A fourth operational phase can be added to this operational cycle, namely that of diffusion/fixation of the leuco in an inert en vironment, since, when operating under nitrogen, that is in an inert environment, the dye bath B impregnating the spooled yams or the generic textile material S being treated, which are never immersed in this dye bath B in either the phases of circulation or the intermediate phases, not only does not oxidise but, remaining in the leuco state, continues its diffusion and fixation action in the textile fibre.

[0055] Operating under nitrogen not only allows operating times to be shortened con siderably, but also allows innovative single-phase dyeing cycles to be performed with high concentrations of the dye baths B and at temperatures higher than the standard temperatures for continuous dyeing lines, and to reduce caustic soda and sodium hy drosulphite consumption by 50% to 80%. Under nitrogen, the chemical reduction of indigo is total and complete and the leuco is disaggregated into nanometric-sized particles. This characteristic, compared to traditional indigo dyeing technology, increases the dyeing capacity of indigo, improves its penetration and intensifies its at tachment to the textile fibre, with considerable savings in water during washing op erations and with excellent results in terms of fastness, intensity and brilliance, particular characteristics which cannot be obtained with traditional indigo dyeing technology.

[0056] A further technological improvement is provided by the possibility, allowed by the very small volume of the dye bath B, to economically apply thermoregulation means 60, 62 to the dye bath B. In particular, these thermoregulation means 60, 62 may be re frigeration means which, for example, allow the dye bath B to be cooled to about 15°C. At this temperature, the indigo dye has the highest affinity with the cellulose fibre, thus obtaining a higher colour yield.

[0057] The dyeing plant 10 according to the present invention also allows an innovative dyeing method which provides for the following single-phase operating cycle, which is however replicable and executed in a totally automatic way, to be carried out. This method of dyeing is however to be considered indicative and not binding, as it can be adapted to various particular production requirements, as well as to the composition and availability of the colour kitchen and/or other particular equipment.

[0058] After the quantity of dye bath B necessary for dyeing a predefined quantity of textile material S has been prepared in the preparation tank 24 and/or 26, the following steps are carried out in sequence:

[0059] a. placing the material-holder devices 32 with the dry textile material S, which is in any case pre-treated directly inside the dyeing compartment 16 or pre treated in dyeing machines according to the prior art, in the dyeing com partment 16; b. inertization of the dyeing compartment 16, and thus of the textile material S and of the preparation/circulation tank 24 and/or 26 for the dye bath B, keeping this dye bath B recirculating within the tank 24 and/or 26; c. when a pre-set residual oxygen value is reached in the dyeing compartment 16, stopping the recirculation of the dye bath B in the preparation/circulation tank 24 and/or 26 and starting the pressure feed of the dye bath B into the textile material S; d. dyeing the textile material S under the necessary conditions and for a predefined time; e. when the time is up, vacuum aspiration of the textile material S one or more times by means of the vacuum vessel 40, to extract the interstitial dye-bath B from the textile material S, retaining of the aspirated dye-bath B inside the vacuum vessel 40 for subsequent delivery to the preparation/circulation tank 24 and/or 26; f. always keeping the textile material S in an inert environment, preferably under nitrogen, for a predefined period of time, for diffusion/fixation of the dye bath B in the textile fibre; g. repeating at least part of step c) and steps d), e), f), if necessary; h. vacuum aspiration of the textile material S, kept in an inert environment, for one or more times by means of the vacuum tank 40, with retention of the aspirated dye bath B in this vacuum tank 40 for subsequent delivery to the preparation/circulation tank 24 and/or 26; i. isolating the dyeing compartment 16 from the hydraulic circuits connected to the dyeing apparatus 12, in particular the hydraulic circuit supplying/ regulating the inert gas N; j. de- inertization of the dyeing compartment 16; k. opening the air supply means 74 and applying vacuum to the textile material S one or more times in order to obtain the final hydro-extraction, with si multaneous oxidation of the dye bath B present on the textile material S; l. performing, with or without intermediate vacuum aspiration, any washing and/or final treatment of the textile material S (which may also be performed in the dyeing machines according to the prior art to increase the productivity of the dyeing plant 10 according to the present invention); m. performing a final vacuum aspiration of the textile material S, if step k) has been carried out; n. removing the material-holder devices 32 with the dyed textile material S from the dyeing compartment 16 for possible centrifuging and final drying.

[0060] For ecological and economic reasons, it should be pointed out that the spent indigo dye baths can be sent to a special tank (not shown) by means of recovery means 78 and, after measurement and addition of the appropriate components, reused, which is not possible in traditional dyeing plants.

[0061] In practice, when used with indigo dye and unlike dyeing machines of the known type, the dyeing plant 10 according to the present invention is not only able to operate according to the particular multiphase operating method specific to indigo dye, but also new special single-phase cycles, all of which can be carried out inside the dyeing apparatus 12, without moving the textile material S, with drastic reductions in the ratio between the weight of the textile material S and the volume of the dye bath B, in the consumption of energy, labour and operating times, chemical products and, above all, water. All in a rational, simple, practical and above all economical and environ mentally sustainable way. Compared to dyeing machines according to the prior art, the dyeing plant 10 according to the present invention is structurally simplified and, while being more complete, practical and rational, is of significantly lower economic commitment.

[0062] Thus, it has been shown that the plant for dyeing yarns in spools and similar textile products according to the present invention with indigo and other reducing dyes achieves the above-mentioned purposes, and in particular has the following ad vantages:

[0063] - a single installation, for dyeing spools of yarn or generic textile material in an inert environment with indigo and other reducing dyes, placed on traditional movable material-holders, with the possibility of wringing the yarn or generic textile material and final oxidation of the dye directly inside the dyeing plant;

- the ratio of the volume of the dye bath to the weight of the textile material is approximately 60% lower than for dyeing machines according to the prior art;

- the indigo dye bath is recovered and reused;

- complete operational dyeing cycles are performed directly in-house; - an ecological dyeing cycle, in an inert environment, with indigo and reducing dyes;

- better diffusion and fixation of the indigo dye to the textile fibre;

- possibility of cooling the indigo dye bath to increase the already higher dyeing yield;

- drastic reduction in the consumption of caustic soda and sodium hydrosulphite when using indigo and other reducing dyes;

- reduced energy consumption;

- drastic reduction in water consumption;

- drastic reduction of sulphites and sulphates in wastewater;

- shorter dyeing times;

- reduced production costs;

- possibility of carrying out single-phase dyeing cycles with high concentration indigo dye baths at temperatures above the standard temperature for continuous dyeing lines;

- maximum operational flexibility;

- possibility of dyeing at variable capacity, in a simple way and with a constant bath ratio;

- possibility of carrying out pre- and post-treatments of textile material in dyeing machines according to the prior art;

- possibility of dyeing (in air) with classes of dyes other than indigo and reduction dyes;

- possibility of also constructing the dyeing plant for operation under static pressure, for dyes other than indigo, with temperatures above 100°C.

[0064] With reference to the dyeing plant disclosed in US 3775055 A, it is pointed out that in the dyeing plant according to the present invention both the dyeing apparatus 12, which contains the textile material S being treated, and at least the first tank 24 for cir culating and preparing the dye bath B and the inert gas N do not operate under either pressure or vacuum. The vacuum suction system, comprising a large vacuum tank 40 with an air pump, does not in fact have the function of initially deaerating the textile material S prior to its being dyed, but rather has the function of dewatering said textile material S after dyeing and passing a large quantity of air through it so that the indigo present in the residual dye bath B impregnating it passes from the leuco state to the oxidised state, thus attaching itself to the textile fibres. The inert environment is not created by simple pressurisation with the inert gas N, but by an automatic mixing system with the internal air which is based on the supply means 46, 48, 50 and the expulsion means 52, 54, 56 for the inert gas N which is arranged to maintain the required percentage of residual oxygen in the various components of the dyeing plant. [0065] In the dyeing plant disclosed in US 3775055 A, both during the vacuum creation operation previously described and also during the dyeing phase, which is provided with a pump with reversal of the direction of circulation of the dye bath, this dye bath is also always present in the lower tank, which is the one containing the textile spools under treatment. In the dyeing plant according to the present invention, instead, cir culation of the dye bath is always one way and the dye bath is never substantially present in the dyeing apparatus 12.

[0066] In the dyeing plant disclosed in US 3775055 A, the second tank, that is the upper one, is described as having a larger capacity than the lower one, and this, together with the reversal of the direction of circulation of the dye bath, clearly indicates that the various treatments can only be carried out at full volume and therefore with a very high bath/textile spool ratio and without the possibility of adjustment for the possible dyeing and/or treatment of low weight batches. On the contrary, the dyeing plant according to the present invention operates with a bath/yarn ratio that is not only very low, but is also always constant with respect to the weight of the textile material S being treated.

[0067] Ultimately, the dyeing plant disclosed in US 3775055 A cannot be used at all for indigo dyeing, since this dyeing plant is unable to perform the necessary sequential operating cycle for the indigo dyeing process, that is dyeing, dehydration and oxidation, directly in-house. On the other hand, the dyeing plant according to the present invention performs the entire indigo dyeing process in-house without moving the textile material S, in a simple, rational, functional and environmentally friendly manner. Its construction and functional design are therefore wholly different from those of the dyeing plant disclosed in US 3775055 A, since the dyeing plant according to the present invention is a very simple and rational dyeing plant, which does not require special material-holder devices, which can use any material-holder device in use in conventional dyeing machines, and which is furthermore complete with all the components necessary to process both single batches of yam and entire lots.

[0068] The plant for dyeing yams in spools and similar textile products with indigo and other reducing dyes is in any case susceptible of many modifications and variations, all within the same inventive concept, and all details may be replaced by technically equivalent elements. In practice, the materials used, as well as the shapes and di mensions, may be any as determined by technical requirements. The scope of protection of the invention is therefore defined by the attached claims.

Claims

[Claim 1] A plant (10) for dyeing textile material (S) comprising:

- at least one dyeing apparatus (12) provided with a housing (14), which encloses at least one dyeing compartment (16), and at least one hermetically sealed closing element (18), which is provided on said housing (14) and allows access to said dyeing compartment (16);

- at least one material-holder frame (20), contained in said dyeing compartment (16);

- at least one tank (24, 26), containing a predefined quantity of at least one dye bath (B);

- at least one first hydraulic supply circuit (28), which is hy draulically connected both to said at least one tank (24, 26) and to said dyeing apparatus (12) to feed said at least one dye bath (B) from said at least one tank (24, 26) to said dyeing compartment (16);

- at least one second hydraulic return circuit (30), which is hy draulically connected to said at least one tank (24, 26) and to said dyeing apparatus (12) to reintroduce the dye bath (B) leaving said dyeing compartment (16) into said at least one tank (24, 26); and

- a plurality of material-holder devices (32) supporting and retaining a predefined amount of said textile material (S), said material-holder devices (32) being mounted on said material- holder frame (20) in such a way that they can be inserted into said dyeing compartment (16) and withdrawn from said dyeing compartment (16) through said at least one closing element (18), wherein both said material-holder frame (20) and said material-holder devices (32) are internally provided with respective ducts (34, 36) for feeding said dye bath (B), said ducts (34, 36) being hydraulically connected to said first hydraulic supply circuit (28) to dynamically supply said dye bath (B) in one direction through said textile material (S), under pressure and in one direction from the inside to the outside of said textile material (S) by means of a plurality of delivery holes (70) provided on said material-holder devices (32), and wherein said dyeing compartment (16) is provided with collection means (38), hydraulically connected to said second hydraulic return circuit (30), for collecting said dye bath (B) which has passed through said textile material (S), so that the dye bath (B) leaving said dyeing compartment (16) is rein troduced into said at least one tank (24, 26) via said second hydraulic return circuit (30), the dyeing plant (10) being characterized in that it comprises at least one vacuum tank (40), which is hydraulically connected to both said dyeing apparatus (12), by means of at least one vacuum suction hydraulic circuit (42), and to said at least one tank (24, 26), by means of at least one hydraulic make-up circuit (44), wherein said at least one vacuum tank (40) is arranged to extract, by means of vacuum suction, the dye bath (B) from the textile material (S) contained in said dyeing compartment (16), as well as to keep said vacuum extracted dye bath (B) inside said vacuum tank (40) and sub sequently send said dye bath (B) to said at least one tank (24, 26), by means of said hydraulic make-up circuit (44), wherein both said housing (14), and said at least one tank (24, 26) are provided with re spective means (46, 48, 50) for supply of an inert gas (N) and means (52, 54, 56) for its respective expulsion within, respectively, said dyeing compartment (16) and said at least one tank (24, 26), and wherein said at least one tank (24, 26) comprises one first hermetically sealed tank (24) for circulating and storing the dye bath (B), said first tank (24) containing both said dye bath (B) and a predefined amount of inert gas (N), said inert gas (N) being supplied via said supply means (48).

[Claim 2] Dyeing plant (10) according to claim 1, characterized in that said dye bath (B) is an indigo-based dye bath and that said inert gas (N) comprises nitrogen.

[Claim 3] Dyeing plant (10) according to claim 1 or 2, characterized in that said at least one tank (24, 26) further comprises at least one second her metically sealed tank (26), which is hydraulically connected to said first hermetically sealed tank (24) by at least one respective hydraulic connecting circuit (58), and which operates as a tank for single total preparation of said dye bath (B) in the presence of said inert gas (N), supplied by means of said supply means (50).

[Claim 4] Dyeing plant (10) according to claim 3, characterized in that at least one of said first hermetically sealed tank (24) and said second her- metically sealed tank (26) is provided with respective means (60, 62) for thermoregulation of the dye bath (B).

[Claim 5] Dyeing plant (10) according to claim 4, characterized in that said means (60, 62) for thermoregulation of said dye bath (B) comprise coils for circulating a thermoregulation fluid, said coils being positioned on respective lower and/or lateral outer portions of at least one of said first hermetically sealed tank (24) and said second hermetically sealed tank (26).

[Claim 6] Dyeing plant (10) according to any one of claims 1 to 5, characterized in that said dyeing apparatus (12) is internally provided with at least one chamber (64) having the function of a buffer vessel to reduce the volume of said inert gas (N) within said dyeing compartment (16).

[Claim 7] Dyeing plant (10) according to any one of claims 1 to 6, characterized in that said material-holder devices (32) are provided with at least one equipment (66) having the function of a buffer vessel for reducing the volume of said inert gas (N) within said dyeing compartment (16).

[Claim 8] Dyeing plant (10) according to any one of claims 1 to 7, characterized in that said housing (14) and/or said vacuum tank (40) are provided with respective air supply means (74, 76) within, respectively, said dyeing compartment (16) and/or said vacuum tank (40).

[Claim 9] Dyeing plant (10) according to any one of claims 1 to 8, characterized in that said first hydraulic supply circuit (28) is provided with re spective means for supplying (68) said inert gas (N), and/or means for recovering (78) said spent dye bath (B), and/or means for discharging (80) said washing fluids.

[Claim 10] Dyeing plant (10) according to any one of claims 1 to 9, characterized in that said collection means (38) comprise at least one collector obtained in a lower portion of said casing (14).

[Claim 11] A method for dyeing textile material (S) using a dyeing plant (10) according to any one of claims 1 to 10, comprising a preliminary step of preparing, in said at least one tank (24, 26), the amount of dye bath (B) required to dye a predefined amount of textile material (S), the method further comprising, in sequence, the steps of: a. placing the material-holder devices (32) with the dry textile material (S) in the dyeing compartment (16); b. inertization of the dyeing compartment (16), and thus of the textile material (S), and the tank (24, 26), keeping said dye bath (B) recirculating within said tank (24); c. when a pre-set residual oxygen value is reached in the dyeing compartment (16), stopping the recirculation of the dye bath (B) in the tank (24, 26) and starting the pressure feed of said dye bath (B) into the textile material (S); d. dyeing the textile material (S) under the necessary conditions and for a predefined time; e. when the time has expired, vacuum aspiration of the textile material (S) one or more times by means of the vacuum tank (40) to extract the interstitial dye bath (B) from said textile material (S), retaining the aspirated dye bath (B) inside said vacuum tank (40) for subsequent delivery of said aspirated dye bath (B) to the tank (24, 26); f. always keeping the textile material (S) in an inert en vironment for a predefined period of time, for diffusion/ fixation of the dye bath (B) in the textile fibre; g. repeating at least part of step c) and steps d), e), f), if necessary; h. vacuum aspiration of the textile material (S), kept in an inert environment, one or more times via the vacuum tank (40), with retention of the aspirated dye bath (B) inside said vacuum tank (40), to subsequently send said aspirated dye bath (B) to the tank (24, 26); i. isolating the dyeing compartment (16) from the hydraulic circuits connected to the dyeing apparatus (12); j. de- inertization of the dyeing compartment (16); k. applying vacuum to the textile material (S) one or more times in order to obtain final hydroextraction with simultaneous oxidation of the dye bath (B) present on said textile material

(S); l. removing the material-holders (32) with the dyed textile material (S) from the dyeing compartment (16) for possible centrifuging and final drying.

[Claim 12] Method according to claim 11, further comprising, after step j) and before step k), the steps of: a. performing, with or without intermediate vacuum aspiration, washing and/or final treatment of the textile material (S); b. performing a final vacuum aspiration of the textile material

(S).

[Claim 13] Method according to claim 11 or 12, wherein the ratio of the weight of the textile material (S) to the volume of the dye bath (B) is about 1/4.