MULTIPURPOSE MACHINE AND METHODS FOR DYEING FABRICS AND WARP YARNS

Abstract

A dyeing machine comprising at least one dyeing module in which a first squeezing device for a textile support, a first treatment tank, a central tank, a second treatment tank and a second squeezing device are located in sequence is described. The dyeing machine also includes a hydraulic system for feeding, circulating and alternately adjusting the levels of process fluids in the tanks. The tanks are preferably enclosed in a hermetically sealed upper covering shell. The two treatment tanks have the same shape, the same dimension and capacity characteristics, and are symmetrical with respect to a plane of symmetry lying in the central tank and arranged perpendicularly with respect to the direction of advance of the textile support. The dyeing machine is provided with means for moving the textile support, configured to advance the textile support alternately in both directions, i.e. either from the first squeezing device to the second squeezing device, sequentially through the tanks, or from the second squeezing device to the first squeezing device, again sequentially through the tanks.

Claims

1. A dyeing machine comprising at least one dyeing module (10) which in turn includes: a first squeezing device (12) for a textile support (100) entering the dyeing module (10), said first squeezing device (12) being configured to extract excess liquids from said textile support (100); a first treatment tank (14) for the textile support (100) coming from said first squeezing device (12), said first treatment tank (14) being located downstream of said first squeezing device (12) and being configured to be at least partly filled with a first process fluid; a central tank (16), located downstream of the first treatment tank (14) and configured to contain said first process fluid or a second process fluid, to prevent oxidation of the textile support (100) when dyeing with the diffusion/fixing of the dye in the fibre of said dyed textile support (100), or to operate in air to oxidise said dyed textile support (100); a second treatment tank (18) for the textile support (100), said second treatment tank (18) being located downstream of the central tank (16) and being configured to be at least partly filled with the same first process fluid that fills the first treatment tank (14), or with another fluid; and a second squeezing device (20) for said textile support (100), located downstream of the second treatment tank (18) and configured to remove excess liquids from said textile support (100), the dyeing machine further comprising: a hydraulic system (62) to alternately supply, circulate and adjust the levels of the first process fluid and the second process fluid in the two treatment tanks (14, 18) and in the central tank (16) respectively; and movement means (36, 38) for moving the textile support (100), the dyeing machine being characterized in that the first treatment tank (14) and the second treatment tank (18) preferably have the same shape and the same dimensional and capacity characteristics, wherein the first treatment tank (14) and the second treatment tank (18) are preferably symmetrical with respect to a plane of symmetry (P) lying in the central tank (16) and arranged perpendicularly with respect to the direction of the forward movement of the textile support (100), and wherein the movement means (36, 38) for moving the textile support (100) are configured to move forward said textile support (100) alternately in both directions, i.e. either from the first squeezing device (12) to the second squeezing device (20) sequentially through the first treatment tank (14), the central tank (16) and the second treatment tank (18), or from the second squeezing device (20) to the first squeezing device (12) sequentially through the second treatment tank (18), the central tank (16) and the first treatment tank (14).

2. The machine according to claim 1, characterized in that the first treatment tank (14), the central tank (16) and the second treatment tank (18) are enclosed by a hermetically sealed upper covering shell (22).

3. The machine according to claim 1, characterized in that it is provided, on each of the two inlet/outlet sides and vice versa for the textile support (100) with respect to the dyeing module (10), with at least one group of rolls (24, 26, 40) for the oxidation of vat dyes in air, wherein there are provided at least one first group of oxidation rolls (24), located at the first squeezing device (12), and at least one second group of oxidation rolls (26), located at the second squeezing device (20), so that the dyeing machine is arranged for alternating stage batch dyeing of fabrics and warp yarns with indigo and other vat dyes in an inert environment.

4. The machine according to claim 3, characterized in that each group of rolls (24, 26, 40) is provided above with at least one respective suction hood (28, 30, 42).

5. The machine according to claim, characterized in that each group of rolls (24, 26, 40) is equipped with at least one respective oxidation intensifier device (32, 34, 44).

6. The machine according to claim 3, characterized in that said movement means (36, 38) for moving the textile support (100) comprise at least one pair of motorised stations for controlled winding/unwinding of the textile support (100) onto/off the respective rolls.

7. The machine according to claim 6, characterized in that at least one first motorised winding/unwinding station (36) is located at the first group of oxidation rolls (24) in a position opposite to the position of the first squeezing device (12), while at least one second motorised winding/unwinding station (38) is located at the second group of oxidation rolls (26) in a position opposite to the position of the second squeezing device (20).

8. The machine according to claim 6, characterized in that there are provided at least two first motorised winding/unwinding stations (36), both located at the first group of oxidation rolls (24) and in a position opposite to the position of the first squeezing device (12), and at least two second motorised winding/unwinding stations (38), both located at the second group of oxidation rolls (26) and in a position opposite to the position of the second squeezing device (20).

9. The machine according to claim 1, characterized in that said first treatment tank (14) and said second treatment tank (18) are dyeing tanks, said first process fluid comprises a dyeing substance and said textile support (100) may be either a fabric or a yarn.

10. The machine according to claim 9, characterized in that each of the first dyeing tank (14), the central tank (16) and the second dyeing tank (18) is internally provided with a plurality of return rollers (54) configured to arrange the textile support (100), which is in discontinuous movement, in a plurality of vertical planes parallel to each other, wherein at least some of said return rollers (54) can be moved in a vertical direction to change the drawing of the textile support (100) into the dyeing module (10).

11. The machine according to claim 9 [[or 10]], characterized in that it comprises two weight-loaded squeezing devices (46, 48) each comprising a pair of rotating idling rollers between which the textile support (100) passes, said two squeezing devices (46, 48) being placed inside the dyeing module (10), wherein a first squeezing device (46) is interposed between the first dyeing tank (14) and the central tank (16), while the second squeezing device (48) is interposed between the central tank (16) and the second dyeing tank (18).

12. The machine according to claim 9, characterized in that the two side dyeing tanks (14, 18) each comprise a respective watertight vertical gate (50, 52) to form two hydraulic sealing cavities between the process fluids, wherein said two vertical gates (50, 52) are provided with a connecting channel at the top between all the tanks (14, 16, 18) and the covering shell (22) so as to form a hydraulic seal for said covering shell (22) along the entire perimeter of the dyeing module (10).

13. The machine according to claim 9, characterized in that the dyeing module (10) is provided with a plurality of foam dye solution dispensers (58) located inside one of the three tanks (14, 16, 18), preferably the central tank (16), said plurality of dispensers (58) being arranged to spray the treated textile support (100) on both the face and reverse sides.

14. The machine according to claim 1, characterized in that said first treatment tank (14), said central tank (16) and said second treatment tank (18) are in mutual fluid communication to form a single treatment volume filled with a single process fluid, typically comprising a dye bath.

15. The Machine according to claim 1, characterized in that it comprises a system (60) for recirculating the textile support (100) that provides means to draw in said textile support (100) as two or more overlapping layers.

Description

[0049] The characteristics and advantages of a machine for the batch dyeing of fabrics and yarns, using alternating stages and any dye, in particular in an inert environment and with indigo and other vat dyes, according to the present invention will be more apparent from the following description by way of example and without limitation, with reference to the attached diagrammatical drawings in which:

[0050] FIG. 1A is a diagrammatical side view in elevation of a multipurpose machine for dyeing a textile support typically comprising fabrics or warp yarns with indigo and other vat dyes in an alternating stage batch system in an inert environment;

[0051] FIG. 1B is a diagrammatical view of the machine in FIG. 1A, but with at least one pair of textile support winding/unwinding stations on each side;

[0052] FIG. 1C is a diagrammatical view of the machine in FIG. 1A, in which the textile support is immersed so as to operate with more layers superimposed, that is in the “loop” system;

[0053] FIG. 1D is a diagrammatical view of the machine in FIG. 1A, but equipped with a pair of multipurpose dyeing modules arranged in line;

[0054] FIG. 1E is a diagrammatical view of the machine in FIG. 1D in which the textile support is immersed so as to operate with more layers superimposed, that is with the “loop” system;

[0055] FIG. 1F is a diagrammatical view of the machine in FIG. 1E in which the textile support is placed with the “loop” system in the first tank and in the traditional way in the second tank;

[0056] FIG. 1G is a diagrammatical view of the machine in FIG. 1E in the version with a pair of textile support winding/unwinding stations arranged on one side only;

[0057] FIGS. 1H and 1I are diagrammatical views of the machine in FIG. 1A, but without the two groups of oxidising rolls;

[0058] FIGS. 1J and 1K are diagrammatical views of the machine in FIG. 1A with a single treatment volume and without a cover;

[0059] FIG. 2 is a diagrammatical side view in elevation of a single multipurpose module of universal application for dyeing fabrics of all kinds, including warp yarns, in an inert environment with an alternating stage batch system, in the preferred operating version for dyeing with indigo, in the stage in which the textile support is advancing from left to right;

[0060] FIG. 3 is the same diagrammatical view as in FIG. 2, in the preferred operating version for indigo dyeing, but in the stage in which the textile support is advancing from right to left;

[0061] FIG. 4 is the same diagrammatical figure as in FIGS. 2 and 3, but in the preferential operating version for dyeing with sulphur-based dyes and in the stages in which the fabric/yarn is advancing both from left to right and from right to left;

[0062] FIG. 5 graphically represents an indicative method for a possible operating cycle for dyeing with indigo, with the individual tanks used in a variety of different ways;

[0063] FIG. 6 graphically represents an indicative method for a possible operating cycle for dyeing with sulphur-based dyes, with the individual tanks used in a variety of different ways;

[0064] FIG. 7 shows a simplified functional diagram of the hydraulic system in the multipurpose dyeing machine;

[0065] FIGS. 8A and 8B show respectively, in diagrammatical side view in elevation, a module as shown in FIGS. 2, 3 and 4 in an alternative version, with the two internal weight-loaded idling rotating squeezers replaced by two pneumatic-pressure motorised squeezers 56, respectively in the preferred operating version for dyeing with indigo and sulphur-based dyestuffs;

[0066] FIG. 8C is a diagrammatical side view in elevation of a dyeing module as shown in FIGS. 8A and 8B in another alternative form of construction which provides for one of the possible special ways of drawing in the treated textile support so that it can be sprayed both on the face and reverse side, preferably from dispensers of foam dye solutions;

[0067] FIG. 9 shows, in diagrammatical side view in elevation, a dyeing module as shown in FIGS. 2, 3 and 4 in another alternative form of use with indigo dye, that is with reduced dipping and diffusion/fixing times, by means of a change in drawing-in;

[0068] FIG. 10 is a diagrammatical side view in elevation of a dyeing module as shown in FIGS. 2, 3 and 4 in another alternative form of use with indigo dye, that is with reduced dipping and diffusion/fixing times, obtained by lowering the upper rolls, without changing the draw-in;

[0069] FIG. 11 is a diagrammatical side view in elevation of a dyeing module as shown in FIGS. 2, 3 and 4 in another alternative form for use with indigo dye, that is with reduced dipping and diffusion/fixing times, obtained either by lowering the upper rolls or by changing the drawing-in; and

[0070] FIG. 12 is a diagrammatical side view in elevation of a dyeing module as shown in FIGS. 2, 3 and 4 in another alternative form for use with indigo dye, where the dyeing takes place, preferably at a low level, in all three tanks.

[0071] It should be noted that the following description and the attached figures do not illustrate many components, accessories and instrumentation normally supplied for this type of dyeing machine, such as devices for spreading and guiding fabrics, inerting, feeding, unloading, heating, automatic dosing, level adjustments, etc., as these are well known to those skilled in the art.

[0072] A multipurpose dyeing machine according to the present invention is shown with reference to the figures. The dyeing machine comprises in sequence at least one dyeing module 10 within which the following components are present in sequence: [0073] a first squeezing device 12 for a textile support 100 entering the dyeing module 10, the first squeezing device 12 being configured to extract excess liquids from such textile support 100. It should be noted that the textile support 100 may comprise either a fabric or a yarn; [0074] a first multipurpose treatment tank 14, typically comprising a dyeing tank, for the textile support 100 coming from such first squeezing device 12. The first treatment tank 14 is located downstream of the first squeezing device 12 and is configured to be at least partly filled with a first process fluid; [0075] a central multipurpose tank 16, located downstream of the first treatment tank 14 and intended to contain the first process fluid or a second process fluid, for example nitrogen, to prevent oxidation of the textile support 100 when dyeing with diffusion/fixing of the dye in the fibre of this dyed textile support 100, or to function in the air to oxidise the dyed textile support 100; [0076] a second multipurpose treatment tank 18, typically comprising a dyeing tank, for the textile support 100. The second treatment tank 18 is located downstream of the central tank 16 and is configured to be at least partly filled with the same first process fluid as fills the first treatment tank 14, or another fluid; [0077] a second squeezing device 20 for such textile support 100, located downstream of the second treatment tank 18 and configured to extract excess liquids from such textile support 100; and [0078] a hydraulic system 62 to supply and circulate the first process fluid and/or the second process fluid respectively in the two treatment tanks 14, 18 and/or the central tank 16, as well as for alternating adjustment of the levels of the first process fluid and/or the second process fluid respectively in the two treatment tanks 14, 18 and/or the central tank 16.

[0079] The first treatment tank 14, the central tank 16 and the second treatment tank 18 are preferably enclosed by a hermetically sealed covering shell 22, located above the dyeing module 10. The first treatment tank 14 and the second treatment tank 18 have preferably the same shape and the same dimensional and capacity characteristics. In addition, the first treatment tank 14 and the second treatment tank 18 are preferably symmetrical to a plane of symmetry P lying in the central tank 16 and arranged perpendicularly to the direction of the forward movement of the textile support 100. The dyeing machine is therefore equipped with moving means configured to move the textile support 100 forward alternately in both directions, that is either from the first squeezing device 12 to the second squeezing device 20 sequentially through the first treatment tank 14, the central tank 16 and the second treatment tank 18, or from the second squeezing device 20 to the first treatment tank 12 sequentially through the second treatment tank 18, the central tank 16 and the first treatment tank 14.

[0080] In the embodiment in FIG. 1A the dyeing machine is set up for dyeing fabrics and warp yarns in a batch system with alternate stages, preferably in an inert environment, with indigo and other vat dyes. The dyeing machine is therefore equipped with at least one group of rolls 24, 26 for oxidation of the vat dyes in air on each of the two inlet/outlet sides and vice versa for the textile support 100 with respect to the dyeing module 10. In particular there is at least one group of oxidation rolls 24 located at the first squeezing device 12 and at least one second group of oxidation rolls 26 located at the second squeezing device 20. Each group of rolls 24, 26 can be equipped with at least one corresponding suction hood 28, 30 above them. Each group of rolls 24 may also be equipped with at least one respective oxidation intensifier device 32, 34.

[0081] The means for moving the textile support 100 may comprise at least one pair of motorised stations 36, 38 for controlled winding/unwinding of the fabric or yarn 100 onto/off the respective rolls. In particular, with reference to the embodiment in FIG. 1A, at least one first motorised winding/unwinding station 36 is located at the first group of oxidation rolls 24 in a position opposite to the position of the first squeezing device 12, while at least one second motorised winding/unwinding station 38 is located at the second group of oxidation rolls 26 in a position opposite to the position of the second squeezing device 20. With reference to the embodiment in FIG. 1B, there are at least two first motorised winding/unwinding stations 36, both located at the first group of oxidation rolls 24 and in a position opposite to the position of the first squeezing device 12, and at least two second motorised winding/unwinding stations 38, both located at the second group of oxidation rolls 26 and in a position opposite to the position of the second squeezing device 20. Moreover, with reference to the embodiment in FIG. 1C, the dyeing machine according to the present invention can be equipped with a system 60 to recirculate the textile support 100 which provides means to achieve looping of this textile support 100 in two or more overlapping layers. In this configuration the dyeing machine therefore operates as in the so-called “loop” system, with the advantage of increasing production capacity.

[0082] Each of the first treatment tank 14, the central tank 16 and the second treatment tank 18 is internally equipped with a plurality of return rollers 54, configured to position the textile support 100, which is in discontinuous movement, in a plurality of vertical planes parallel to each other. In particular at least some of these return rollers 54 can be moved in a vertical direction to change the way the textile support 100 is drawn into the dyeing module 10, as will be more particularly specified below.

[0083] In the embodiment in FIG. 1D the multipurpose dyeing machine comprises in sequence: [0084] at least one first motorised winding/unwinding station 36 for the rolls for fabric or yarns 100; [0085] at least one first group of oxidation rolls 24, preferably equipped with a corresponding suction hood 28 and a corresponding oxidation intensifier device 32; [0086] a first dyeing module 10; [0087] at least one second group of oxidation rolls 26, preferably equipped with a corresponding suction hood 30 and a corresponding oxidation intensifier device 34; [0088] a second dyeing module 10; [0089] at least one third group of oxidation rolls 40, preferably equipped with a corresponding suction hood 42 and a corresponding oxidation intensifier device 44; and [0090] at least one second motorised winding/unwinding station 38 for the rolls for fabric or yarns 100.

[0091] This embodiment, having one more multipurpose dyeing module 10 than the previous embodiments in FIGS. 1A and 1B, has only the advantage of halving the number of dyeing alternations with the same result and therefore almost doubling production capacity.

[0092] The embodiment in FIG. 1E is the same as FIG. 1D, with only the variant of providing for the system 60 to recirculate the textile support 100 so that such textile support 100 is drawn in as two or more overlapping layers, as in the so-called “loop” system, with the advantage of increasing production capacity. The embodiment in FIG. 1F is the same as in FIG. 1E with the difference that the system 60 for recirculating the textile support 100 drawing in such textile support 100 as two or more overlapping layers is limited to the first multipurpose dyeing module 10, which is therefore intended only for dyeing. The second multipurpose dyeing module 10 is intended for auxiliary operations, thus avoiding the module cleaning operations necessary when changing over a batch. The embodiment in FIG. 1G is the same as in FIG. 1E with the difference that the two motorised stations 36, 38 for winding/unwinding the textile support 100 are arranged on one side only, with the advantage of easy operation and simplification of the path of the textile support 100 in the recirculation system 60.

[0093] In the embodiment in FIGS. 1H and 1I the multipurpose dyeing machine is constructed in sequence as in FIG. 1A, without however the two lateral groups of oxidation rolls. This simplified version makes it possible to produce a new fabric dyeing machine of the traditional classic type which because of all its special characteristics makes “jiggers” technologically and functionally obsolete.

[0094] Regardless of the form of construction, in comparison with traditional “jiggers” the multipurpose dyeing machine according to the present invention is further equipped with: [0095] two squeezing devices 12, 20, each of which preferably comprises a pair of pneumatic pressure rolls located externally at the ends of a single dyeing module 10, with the possibility of alternating their direction of travel; [0096] two weight-loaded squeezing devices 46, 48, each comprising a pair of rotating idling rollers between which the fabric or yarn 100 passes, placed inside the dyeing module 10. More specifically, a first squeezing device 46 is interposed between the first treatment tank 14 and the central tank 16, while the second squeezing device 48 is interposed between the central tank 16 and the second treatment tank 18; [0097] the dyeing module 10 has a much longer draw-in and is divided into three watertight compartments, operating in an inert environment, with the possibility of performing two different dyeing operations and/or two treatments at the same time. Also, there is the central tank 16 for diffusion/fixing of the dye in an inert environment between the two treatment tanks 14, 18 located at the two ends of the dyeing module 10. This central tank can also be used as a dyeing or washing tank; [0098] an in-tank hydraulic system for inerting, feeding and alternating adjustment of bath levels in the two treatment tanks 14, 18, circulating the dye bath for use in the two sequential treatment tanks 14, 18, also for different treatments and processes, as well as also using the dye diffusion/fixing tank 16 for dyeing and washing; [0099] at least one group of oxidation rolls 24, 26, 40, placed on each side of a single dyeing module 10 for the oxidation of vat dyes in air. Each group of oxidation rolls 24, 26, 40 is preferably equipped with a corresponding suction hood 28, 30, 42 and a corresponding oxidation intensifier device 32, 34, 44; and [0100] at least two motorised stations 36, 38 for the controlled and alternating winding/unwinding of the fabric or yarn 100.

[0101] As a consequence, always in comparison with a traditional “jigger”, the multipurpose dyeing machine according to the present invention makes it possible to obtain the following operating advantages: [0102] possibility of dyeing with indigo and vat dyes several consecutive times, according to the overdyeing procedure, to intensify of the shade of colour; [0103] possibility of longer lengths of fabric and/or yarn 100 being treated, as the motorised winding/unwinding stations 36, 38 are outside the dyeing module 10, independent of each other and can also be of large diameter; [0104] direct use of rolls of fabric from previous processes, such as: singeing, mercerising, scouring and bleaching; [0105] possibility of differentiating bath/fibre contact times by reducing the bath level in the tanks and/or the length of immersed fabric or yarn, by changing the draw-in, including in the diffusion/fixing area; [0106] dyeing in an inert environment, with unparalleled quality characteristics, exceptional colour rendering, reduction in caustic soda and sodium hydrosulphite consumption, with greater penetration and fixation of the dye, and with a significant saving in wash water; [0107] hitherto unimaginable operating versatility.

[0108] FIGS. 1J and 1K are diagrammatical side views in elevation of the machine in FIG. 1A provided with a single treatment volume and without the covering shell. In other words, in this embodiment the first treatment tank 14, the central tank 16 and the second treatment tank 18 are in fluid communication with each other to form a single treatment volume filled with a single process fluid, typically comprising a dye bath. This solution, working with a single bath at maximum level, i.e. with the upper return rollers 54 and therefore also all of the textile support 100 in the dyeing module 10 covered, makes it possible to dye in air with any dye, but also with indigo and other vat dyes as in traditional continuous dyeing machines.

[0109] FIG. 2 shows a single multipurpose dyeing module 10, in the preferred operating version for indigo dyeing and in the stage in which the fabric or yarn 100 is advancing from left to right. In addition to operating in an inert environment, in comparison with a tank for the continuous dyeing of fabrics and/or warp yarns with indigo in air in a traditional plant, this multipurpose dyeing module 10 differs because of: [0110] the division into three watertight compartments (tanks); [0111] the two lateral treatment tanks 14, 18, each of which includes a respective vertical watertight gate 50, 52 to form two hydraulic sealing cavities between the process fluids and the external environment for entry and exit of the belt of fabric and/or yarn 100, without the release of inert gas; [0112] the two vertical watertight gates 50, 52 have a connecting channel at the top between all tanks 14, 16, 18 and the covering shell 22 so as to form a hydraulic seal for such covering shell 22 around the entire perimeter of the multipurpose dyeing module 10; [0113] location of a motorised pneumatic pressure squeezing device 12 outside, upstream of the first treatment tank 14; [0114] possibility for the two squeezing devices 12, 20 to alternate the direction of travel; [0115] location of the respective weight-loaded squeezing devices 46, 48 with idling rotating rollers within the dye diffusion/fixing area, above the vertical walls of the tanks 14, 18; [0116] possibility for the two treatment tanks 14, 18 to operate with high- and low-level bath alternately according to the needs and/or the direction of the forward movement of the textile support 100 being treated, as shown for example in FIGS. 2 and 3; [0117] supplementing it with the hydraulic system 62 for alternating adjustment of the bath levels in the two treatment tanks 14, 18; [0118] supplementing the hydraulic system 62 with the in-tank circulation system shown in detail in FIG. 7, for use of the three tanks 14, 16, 18 in sequence, including for different treatments and processes.

[0119] The multipurpose dyeing module 10 in FIG. 8C provides that the textile support 100 being treated is sprayed on both the face and the reverse side by a plurality of foam dyeing solution dispensers 58 located inside one of the three tanks 14, 16, 18, preferably the central tank 16. This dyeing system is one of the most economical and eco-sustainable. Naturally the scope of protection of this invention also includes all the other possible systems of application of vat dye solutions to the fabric and/or yarn, always in an inert environment, such as laminar jets, spraying, atomising, coating, doctoring, etc., and in any event all systems that do not require the fabric and/or yarn to be immersed in the aqueous solutions present in traditional dyeing tanks.

[0120] The multipurpose dyeing module 10 in FIG. 9 is configured to operate in an inert environment, with indigo and other vat dyes. In particular, with respect to the embodiments shown in FIGS. 2, 3 and 4, this multipurpose dyeing module 10 operates according to an alternative method of dyeing with indigo dye, i.e. with reduced dipping and diffusion/fixing times, by changing the draw-in.

[0121] The multipurpose dyeing module 10 in FIG. 10 operates according to another alternative method for dyeing with indigo dye, i.e. with reduced dipping and diffusion/fixing times and by lowering the upper return rollers 54 without changing the draw-in. The multipurpose dyeing module 10 in FIG. 11 operates according to another alternative method for dyeing with indigo dye, i.e. with reduced dipping and diffusion/fixing times, and by both lowering the upper return rollers 54 and changing the draw-in.

[0122] Finally, the multipurpose dyeing module 10 in FIG. 12 operates according to another alternative dyeing method, i.e. with the indigo dye bath, preferably at a low level, in all three tanks 14, 16, 18. In this condition, working with many alternations of dyeing in a bath with a low concentration of indigo dye, dyes with very dark shades and exceptional colour-fastness, characteristic of the famous “Japanese denim”, much in demand by the style elite, are obtained. This multipurpose dyeing module 10 adds the new technology of dyeing in an inert environment to the traditional technology of continuous dyeing of fabrics and warp yarns with indigo and other vat dyes in air, in a simple, economical and rational way, with all its strengths and advantages.

[0123] It will therefore be seen that the multipurpose dyeing machine with an alternating stage batch system for fabrics and warp yarns according to the present invention has accomplished the objects set out above. The multipurpose dyeing machine with an alternating stage batch system for fabrics and warp yarns, preferably with indigo and other vat dyes, according to the present invention accomplishes the objects mentioned in the preamble of the description. It should be noted that in order to have maximum flexibility in the final result, in terms of ring dyeing and the dye's depth of penetration and fixation, in addition to the known physical/chemical variables, the above machine is also designed to vary the bath-fibre contact time by reducing the level of the dyeing tanks and/or the length of the immersed fabric and/or yarn, by changing the draw-in, including in the diffusion/fixing area. The multipurpose dyeing machine according to the present invention also offers the possibility of dyeing small batches of fabric and yarn, i.e. the small batches of yarn that are increasingly in demand on the market. It should also be noted that, for the sake of simplicity of explanation, both in the preamble and in the description the term ‘rolls’ has been used indiscriminately for both fabrics and warp yarns. In the case of yarns, it is in fact intended that they may also be presented flat, on one or more reels, bobbins, etc., or as ropes, as one or more “balls”, or even in layers, in appropriate containers. The multipurpose dyeing machine with an alternating stage batch system for fabrics and warp yarns according to the present invention conceived in this way is in any event susceptible of numerous modifications and variations, all falling within the same inventive concept; moreover, all details may be replaced by technically equivalent elements. In practice, any materials as well as any shapes and dimensions may be used, depending on technical needs. The scope of protection of the invention is therefore defined by the appended claims.