Multifunctional continuous dyeing apparatus of warp chains for fabrics

Abstract

A multifunctional continuous dyeing apparatus provided at a bottom with a main body within which are formed in a sequence, with reference to the feeding direction of the yarn, at least a first dyeing group for the yarn, provided with a respective first squeezing device of the yarn, an oxidation or diffusion/fixation group, placed downstream of the first dyeing group and arranged for the oxidation of the dyed yarn or for the diffusion/fixation of the dye in the fiber of the dyed yarn, and at least a second dyeing group of the yarn, arranged downstream of the oxidation or diffusion/fixation group and in turn provided with a respective second squeezing device of the yarn, where at least the first dyeing group, the first squeezing device, the oxidation or diffusion/fixation group and the second dyeing group are hermetically sealing enclosed by at least one covering case, integral at the top with the main body, and provided with a plurality of doors which are at least partially openable to perform the dyeing of the yarn in an environment exposed to air and which are reclosable to perform the dyeing of the yarn in an inert environment under nitrogen.

Claims

1. Multifunctional continuous dyeing apparatus for a yarn, the dyeing apparatus being provided at a bottom with a main body inside which the following are obtained in sequence, with reference to a feeding direction of the yarn: at least one first dyeing group configured for dyeing the yarn, provided with a corresponding first squeezing device configured for squeezing said yarn; an oxidation or diffusion/fixation group, placed downstream of the at least one first dyeing group and arranged for the oxidation of the dyed yarn, or for the diffusion/fixation of the dye in the fiber of said dyed yarn; wherein at least the at least one first dyeing group, the first squeezing device, and the oxidation or diffusion/fixation group are hermetically sealing enclosed by at least one covering case, integral at a top with the main body, wherein at least part of the at least one covering case is provided, on at least part of side surfaces of at least one covering case, with a plurality of doors, wherein said plurality of doors pass from an at least partially opening configuration, wherein said plurality of doors are at least partially open to perform the dyeing of the yarn in an environment exposed to air to a seal closing configuration wherein said plurality of doors are seal closed to perform the dyeing of said yarn in an inert environment, wherein the at least one covering case is provided with at least one outlet opening configured to let out said yarn from the dyeing apparatus when the dyeing of said yarn is performed in an inert environment, while ensuring the sealed closure of the at least one covering case, wherein the oxidation or diffusion/fixation group is provided with one or more respective oxidation intensifier devices configured to generate a plurality of air flows that facilitate the oxidation of the yarn.

2. Dyeing apparatus according to claim 1, wherein the at least one first dyeing group comprises a respective first dyeing tank, internally provided with a plurality of first return rollers on which the yarn winds and arranged to contain a dye bath in which said yarn is immersed.

3. Dyeing apparatus according to claim 1, wherein the oxidation or diffusion/fixation group comprises a plurality of upper return rollers and a plurality of lower return rollers configured to arrange the yarn, which is in continuous movement, on a plurality of vertical planes.

4. Dyeing apparatus according to claim 1, wherein each oxidation intensifier device is made of two blowing groups having substantially identical conformation and opposite one another, each blowing group being provided with at least one respective fan, as well as with a respective plurality of converging ducts placed downstream of the respective fan, arranged equidistant from one another and along development directions that are transversal to the feeding direction of the yarn into the dyeing apparatus.

5. Dyeing apparatus according to claim 1, wherein each oxidation intensifier device can be disabled and isolated from the oxidation or diffusion/fixation group in order to arrange the dyeing apparatus to perform dyeing in an inert environment.

6. Dyeing apparatus according to claim 2, wherein at least one second dyeing group comprises a respective second dyeing tank, internally provided with a plurality of second return rollers in which the yarn is immersed and which is arranged to contain a dye bath in which said yarn is immersed, said second dyeing tank also being internally provided with a partition element configured to divide said second dyeing tank into two separate volumes.

7. Dyeing apparatus according to claim 6, wherein one of the the two separate volumes of the second dyeing tank is arranged to contain a quantity of dye bath less than the quantity of dye bath contained in the first dyeing tank when the dyeing of said yarn is performed in an inert environment.

8. Dyeing apparatus according to claim 1, wherein an inlet opening with a watertight wall is obtained in the main body, opening through which the yarn is introduced into the at least one first dyeing group passing on a respective guide roller.

9. Continuous dyeing plant for dyeing a yarn, comprising at least one first dyeing apparatus and at least one second dyeing apparatus, the at least one first and at least one second dyeing apparatuses according to claim 1, said at least one first dyeing apparatus and said at least one second dyeing apparatus being arranged sequentially whereby said dyeing plant being arranged to subject the yarn to a first dyeing process performed in sequence in the at least one first dyeing apparatus and in the at least one second dyeing apparatus, a return path for the yarn being interposed between the corresponding squeezing device of the at least one second dyeing apparatus and the at least one first dyeing group of the at least one first dyeing apparatus, said return path being configured to make said yarn to repeat at least one second dyeing process still performed in sequence in the at least one first dyeing apparatus and in the at least one second dyeing apparatus.

10. Continuous dyeing process for dyeing a yarn through a dyeing apparatus according to claim 1, the process comprising: immersing the yarn into said at least one first dyeing group containing a dye bath; exerting a first squeezing on the yarn exiting from the dye bath of said at least one first dyeing group; and subjecting the yarn to an intermediate step in said oxidation or diffusion/fixation group, wherein said intermediate step in said oxidation or diffusion/fixation group is either a step of oxidation of the yarn in an environment exposed to air that is obtained through the at least partial opening of said plurality of doors, or a step of diffusion and fixation of the dye to the fiber of said yarn in an inert environment that is obtained through the seal closure of said plurality of doors.

11. Dyeing process according to claim 10, further comprising, after said step of oxidation of the yarn in an environment exposed to air, the steps of: immersing the yarn into said at least one second dyeing group containing a dye bath; and exerting a second squeezing on the yarn exiting from the dye bath of said at least one second dyeing group.

12. Dyeing process according to claim 10, further comprising, after said step of diffusion and fixation of the dye to the fiber of said yarn in an inert environment, the steps of: immersing the yarn with short threading, i.e. with a shorter threading than the maximum threading that yarn can have throughout the at least one second dyeing group into a predefined portion of said at least one second dyeing group, said at least one second dyeing group containing a dye bath of reduced volume; and exerting a second squeezing on the yarn exiting from the dye bath of said at least one second dyeing group.

13. Dyeing process according to claim 10, further comprising, before said step of diffusion and fixation of the dye to the fiber of said yarn in an inert environment, a step of at least partial filling with water said at least one second dyeing group, said water having a hydraulic seal function in order to avoid nitrogen leakage, and further comprising, after said step of diffusion and fixation of the dye to the fiber of said yarn in an inert environment, an outlet step of said yarn from the dyeing apparatus through at least one outlet opening provided in said oxidation or diffusion/fixation group.

14. Dyeing process according to claim 10, further comprising, at the end of said dyeing process, a step of return of the yarn to said at least one first dyeing group through a return path.

15. Dyeing apparatus according to claim 1, wherein at least one second dyeing group for the yarn, placed downstream of the oxidation or diffusion/fixation group and provided in turn with a corresponding second squeezing device for said yarn, wherein said at least one second dyeing group is placed inside said main body, wherein said at least one second dyeing group is hermetically sealing enclosed by the at least one covering case, integral at the top with the main body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The features and the advantages of a multifunctional continuous dyeing apparatus for a yarn chains according to the present disclosure will become apparent from the following exemplary and non-limiting description, made with reference to the accompanying schematic drawings, in which:

(2) FIG. 1 is a schematic, side elevation view of a multifunctional continuous dyeing apparatus for yarn chains according to the present disclosure, with the yarn threaded in all the groups of the apparatus itself, and with the lateral windows open, for dyeing in the air;

(3) FIG. 2 is a schematic, side elevation view of the dyeing apparatus of FIG. 1, with the yarn fully threaded in the first two groups of the apparatus itself and only partially in the second compartment of the second dyeing tank, and with the lateral windows sealably closed, for dyeing under nitrogen;

(4) FIG. 3 is a schematic, side elevation view of the dyeing apparatus of FIG. 1, with the yarn fully threaded only in the first two groups of the apparatus itself, with output of the yarn from the sealing device and with the lateral windows sealably closed, for dyeing under nitrogen. In this configuration, the second dyeing tank of the second dyeing group is filled with water, with sealing function to prevent leakage of nitrogen;

(5) FIG. 4 is an isometric sectional view of an oxidation intensifier device applied in the central group of the dyeing apparatus of FIG. 1;

(6) FIG. 5 is a plan view of the dyeing apparatus of FIG. 1 provided with the oxidation intensifier device of FIG. 4;

(7) FIG. 6 is a side elevation view of only the dyeing tanks of a traditional continuous dyeing plant with indigo;

(8) FIG. 7 is a side elevation view of two multifunctional continuous dyeing apparatuses for yarn chains according to the present disclosure, forming a dyeing plant, with the yarn threaded in all the groups of the apparatuses themselves, and with the lateral windows open. In this dyeing plant, after the fourth dyeing the yarn is returned to the first tank of the first apparatus to repeat four more steps, thus doubling the number of dyes;

(9) FIG. 8 is a side elevation view of two multifunctional dyeing apparatuses according to the present disclosure, forming a dyeing plant, with the yarn fully threaded in the first two groups and only in the second compartment of the second dyeing tank for each apparatus, and with the lateral windows sealably closed, for dyeing under nitrogen. This dyeing plant can be used in line (4 dyes), due to the possibility of working with more concentrated baths and thus with few tanks, or alternatively with the return to the first tank of the dyed yarn exiting from the fourth tank, threaded only in the second compartment, for doubling the dyes (8 dyes);

(10) FIG. 9 is a side elevation view of two multifunctional dyeing apparatuses according to the present disclosure, forming a dyeing plant, with the yarn fully threaded in the first two groups and with exit of the yarn itself from the sealing device for each apparatus, and with the lateral windows sealably closed, for dyeing under nitrogen. This dyeing plant can be used in line (4 dyes), due to the possibility of working with more concentrated baths and thus with few tanks, or alternatively with the return to the first tank of the dyed yarn exiting from the fourth tank, threaded only in the second compartment, for doubling the dyes (8 dyes); and

(11) FIGS. 10 to 15 show respective embodiments of the multifunctional continuous dyeing apparatus for yarn chains according to the present disclosure.

DETAILED DESCRIPTION

(12) It is noted that in the following description and in the accompanying figures, numerous components, accessories and instruments normally supplied with this type of plants and apparatuses, such as inertisation, filling, discharge, heating, dye bath circulation, dehumidification devices etc. are not shown as they are well known to a person skilled in the art.

(13) With reference to the figures, a multifunctional continuous dyeing apparatus for yarn chains is shown, according to the present disclosure, indicated as a whole with reference numeral 10. In particular, apparatus 10 is configured to dye rope or flat warp chains, for fabrics and is designed to work both with the indigo dye and with other dyes.

(14) The dyeing apparatus 10 is provided at the bottom with a main body 12. Within the main body 12 are obtained in a sequence, with reference to the feeding direction F of a yarn 100, the following processing groups of such a yarn 100: at least one first dyeing group 14 for dyeing the yarn 100, provided with a corresponding first squeezing device 16 for squeezing such a yarn 100, and an oxidation or diffusion/fixation group 18, placed downstream of the first dyeing group 14 and configured for the oxidation of the dyed yarn 100, in the case of dyeing in the air, or for the diffusion/fixation of the dye in the fiber of such a dyed yarn 100, in the case of dyeing under nitrogen.

(15) The dyeing apparatus 10 then comprises, downstream of the oxidation or diffusion/fixation group 18, at least a second dyeing group 20 of yarn 100, in turn provided with a relative second squeezing device 22 of such a yarn 100.

(16) At least the first dyeing group 14, the first squeezing device 16, the oxidation or diffusion/fixation group 18 and the second dyeing group 20 are enclosed by at least an upper hermetically sealed covering case 24, integral with the main body 12. Each covering case 24 may be made integrally with the main body 12, or it may be removably fixed to the main body 12 through the interposition of seals 70.

(17) At least part of the covering cases 24 is provided, on at least part of the lateral surfaces of such a covering case 24, with a plurality of doors 26 that open and are resealable. Doors 26 are to be opened in the case of dyeing in the air. The covering case 24 may also be provided with at least one outlet device or at least one outlet opening 28 for the yarn 100, through which said yarn 100 exits from the dyeing apparatus 10 in case of dyeing under nitrogen, while ensuring the sealed closure of the covering case 24.

(18) As shown in FIG. 1, which illustrates the dyeing apparatus 10 configured to carry out a traditional dyeing in the air, yarn 100 is fed from left to right, with reference to the representation of the dyeing apparatus 10, in the direction of arrows F. Yarn 100 is then introduced into the first dyeing group 14 through a respective inlet opening 30 with a watertight wall obtained into the main body 12, and passing on a respective guide roller 32. The first dyeing group 14 comprises a respective first dye tank 34 into which yarn 100 is immersed, winding on a plurality of first return rollers 36. In the first dyeing tank 34, yarn 100 is immersed in a dye bath. The dye bath may be composed, for example, of an alkaline solution of indigo dye.

(19) At the exit of the first dyeing tank 34, yarn 100 undergoes a first squeezing by passing between a pair of first squeezing rollers 38 of the first squeezing device 16. The first squeezing rollers 38 are the so-called squeezing “gadder”.

(20) Downstream of the first squeezing device 16, yarn 100 is introduced into the oxidation or diffusion/fixation group 18. The oxidation or diffusion/fixation group 18 comprises a plurality of upper return rollers 40 and a plurality of lower return rollers 42. The upper 40 and lower 42 return rollers are configured to arrange yarn 100, which is in continuous movement, on a plurality of vertical planes.

(21) In the configuration of the dyeing apparatus 10 of FIG. 1, doors 26 of the covering case 24 are at least partially open. In the oxidation or diffusion/fixation group 18, the oxidation of yarn 100 takes place through exposure to air.

(22) Downstream of the oxidation or diffusion/fixation group 18, yarn 100 is introduced into the second dyeing group 20. The second dyeing group 20 comprises a respective second dye tank 44 into which yarn 100 is immersed, winding on a plurality of second return rollers 46.

(23) The second dyeing tank 44 is internally provided with a wall 68, configured to divide said second dyeing tank 44 into two separate volumes 44A and 44B. Preferably, the first volume 44A is greater than the second volume 44B. In the case of dye in the air, both volumes 44A and 44B of the second dyeing tank 44 are filled with the dye bath and are used simultaneously. In the case of dyeing under nitrogen, the second volume 44B of the second dyeing tank 44 is arranged to contain a quantity of dye bath less than the quantity of dye bath contained in the first dyeing tank 34. At the exit of the second dyeing tank 44, yarn 100 undergoes a second squeezing by passing between a pair of second squeezing rollers 48 of the second squeezing device 22.

(24) The oxidation or diffusion/fixation group 18 is provided with one or more respective oxidation intensifier devices 50, configured to generate a plurality of air flows that facilitate the oxidation process of the yarn 100. As shown in FIGS. 4 and 5, each oxidation intensifier device 50 may be composed, for example, of two blowing groups 52 and 54 having a substantially identical shape and opposed one another. Each blowing group 52 and 54 is provided with a respective fan 56 and 58 as well as a respective plurality of convergent ducts 60 and 62, arranged downstream of the respective fan 56 and 58 and preferably arranged equally spaced from each other and along development directions that are transversal to the feeding direction of yarn 100 in the dyeing apparatus 10. Each oxidation intensifier device 50 can be deactivated and isolated from the oxidation or diffusion/fixation group 18 by known means in order to arrange the dyeing apparatus 10 to carry out dyeing under nitrogen.

(25) FIG. 2 shows the dyeing apparatus 10 configured to carry out dyeing in an inert atmosphere under nitrogen. In this operating configuration, yarn 100 is threaded and completely immersed in the first dyeing group 14 and is threaded in the oxidation or diffusion/fixation group 18, while such a yarn 100 is only partially threaded in the second dyeing group 20. In other words, yarn 100 is threaded only in the second volume 44B of the second dyeing tank 44 and only this second volume 44B is filled with a respective dye bath.

(26) In the configuration of the dyeing apparatus 10 of FIG. 2, doors 26 of the covering case 24 are completely sealably closed. In the oxidation or diffusion/fixation group 18 then the diffusion and fixation of the dye on the fiber of yarn 100 take place due to the presence of nitrogen within such an oxidation or diffusion/fixation group 18.

(27) FIG. 3 shows the dyeing apparatus 10 configured to carry out dyeing in an inert atmosphere under nitrogen based on a further operating configuration. In this operating configuration, yarn 100 is threaded and completely immersed in the first dyeing group 14 and is threaded in the oxidation or diffusion/fixation group 18. In this operating configuration, however, yarn 100 does not undergo additional dyeing steps and is arranged to directly exit from the oxidation or diffusion/fixation group 18 through the respective outlet device 28. In other words, yarn 100 is not introduced into the second dyeing group 20, while the second volume 44B of the second dyeing tank 44 is filled with water that only has a function of hydraulic seal to prevent the leakage of nitrogen from the oxidation or diffusion/fixation group 18 and, thus, from the dyeing apparatus 10.

(28) FIG. 7 shows a continuous dyeing plant for yarn chains, comprising two separate dyeing apparatuses 10A and 10B arranged in series. This dyeing plant is arranged to subject yarn 100 to a first dyeing process carried out in a sequence in the first dyeing apparatus 10A and in the second dyeing apparatus 10B. Between the second squeezing device 22 of the second dyeing apparatus 10B and the first dyeing group 14 of the first dyeing apparatus 10A is interposed a return path 64 for yarn 100, configured to make such a yarn 100 repeat at least a second dyeing process again carried out in a sequence in the first dyeing apparatus 10A and in the second dyeing apparatus 10B.

(29) In the configuration in FIG. 7, yarn 100 is threaded in all the respective groups 14, 18 and 20 of the first dyeing apparatus 10A and of the second dyeing apparatus 10B. Both dyeing apparatuses 10A and 10B have the respective doors 26 open. The dyeing plant is therefore arranged to carry out the traditional dyeing in the air.

(30) In detail, in the first dyeing group 14 of the first dyeing apparatus 10A, a first dyeing step of yarn 100 is carried out, followed by a squeezing step and an oxidation step in the oxidation or diffusion/fixation group 18 of such a first dyeing apparatus 10A. In the second dyeing group 20 of the first dyeing apparatus 10A, a second dyeing step of yarn 100 is then carried out, followed by a squeezing step and an oxidation step in an external path 66 interposed between the first dyeing apparatus 10A and the second dyeing apparatus 10B.

(31) In the first dyeing group 14 of the second dyeing apparatus 10B, a third dyeing step of yarn 100 is then carried out, followed by a squeezing step and an oxidation step in the oxidation or diffusion/fixation group 18 of such a second dyeing apparatus 10B. In the second dyeing group 20 of the second dyeing apparatus 10B, a fourth dyeing step of yarn 100 is then carried out, followed by a squeezing step and a return step of such a yarn 100 to the first dyeing apparatus 10A through the return path 64. This return path 64 also has function of oxidizer.

(32) The above process in air is then repeated at least once, thus obtaining a fifth, a sixth, a seventh and an eighth dyeing step of yarn 100, interspersed with respective squeezing and oxidation steps. This dyeing process is perfectly identical to the traditional one, which can be obtained for example in the eight dyeing tanks of the dyeing plant of known type shown in FIG. 6, but with an evident saving in terms of size of the plant and, therefore, of space, cost, installed power, volumes of dye baths, etc.

(33) In the configuration of FIG. 8, yarn 100 is fully threaded in the first two groups 14 and 18 and only in the second volume 44B of the second dyeing tank 44 for each one of the first dyeing apparatus 10A and the second dyeing apparatus 10B. Both dyeing apparatuses 10A and 10B have the respective doors 26 hermetically closed. The dyeing plant is therefore arranged to carry out dyeing under nitrogen.

(34) In detail, in the first dyeing group 14 of the first dyeing apparatus 10A, a first dyeing step of yarn 100 is carried out, followed by a squeezing step and a diffusion/fixation step of the dye on such a yarn 100 in the oxidation or diffusion/fixation group 18 of such a first dyeing apparatus 10A. In the second dyeing group 20 of the first dyeing apparatus 10A, a second dyeing step of yarn 100 is then carried out (with short threading in the second volume 44B of the second dye tank 44 only, i.e. with a shorter threading than the maximum threading that yarn 100 can have throughout the second dyeing group 20), followed by a squeezing step and an oxidation step in an external path 66 exposed to air and interposed between the first dyeing apparatus 10A and the second dyeing apparatus 10B.

(35) In the first dyeing group 14 of the second dyeing apparatus 10B, a third dyeing step of yarn 100 is then carried out, followed by a squeezing step and a diffusion/fixation step of the dye on such a yarn 100 in the oxidation or diffusion/fixation group 18 of such a second dyeing apparatus 10B. In the second dyeing group 20 of the second dyeing apparatus 10B, a fourth dyeing step of yarn 100 is then carried out (again with short threading in the second volume 44B of the second dyeing tank 44 only), followed by a squeezing step and a return step of such a yarn 100 to the first dyeing apparatus 10A through the return path 64. This return path 64 also has function of oxidizer.

(36) The above process under nitrogen may then be repeated at least once, thus obtaining a fifth, a sixth, a seventh and an eighth dyeing step of yarn 100, interspersed with respective diffusion/fixation and oxidation steps. With the dyeing plant in the configuration of FIG. 8 it is therefore possible to carry out four dyeing steps if the plant is used in line, or eight dyeing steps if the return path 64 is also used.

(37) In the configuration of FIG. 9, yarn 100 is fully threaded in the first two groups 14 and 18 of each one of the first dyeing apparatus 10A and the second dyeing apparatus 10B. Yarn 100 therefore exits from each dyeing apparatus 10A and 10B through the outlet devices 28 of the respective covering cases 24. Both dyeing apparatuses 10A and 10B have the respective doors 26 hermetically closed, while the second volume 44B of the second dyeing tank 44 of each dyeing apparatus 10A and 10B is filled with water. The dyeing plant is therefore arranged to carry out dyeing under nitrogen.

(38) In detail, in the first dyeing group 14 of the first dyeing apparatus 10A, a first dyeing step of yarn 100 is carried out, followed by a squeezing step and a diffusion/fixation step of the dye on such a yarn 100 in the oxidation or diffusion/fixation group 18 of such a first dyeing apparatus 10A. Yarn 100 then comes out from the first dyeing apparatus 10A to undergo an oxidation step in an external path 66 exposed to air and interposed between the first dyeing apparatus 10A and the second dyeing apparatus 10B.

(39) In the first dyeing group 14 of the second dyeing apparatus 10B, a second dyeing step of yarn 100 is then carried out, followed by a squeezing step and a diffusion/fixation step of the dye on such a yarn 100 in the oxidation or diffusion/fixation group 18 of such a second dyeing apparatus 10B. Yarn 100 then comes out of the second dyeing apparatus 10B to be returned until the first dyeing apparatus 10A through the return path 64. This return path 64 also has function of oxidizer.

(40) The above second process under nitrogen may then be repeated at least once, thus obtaining a third and a fourth dyeing step of yarn 100, interspersed with respective squeezing, diffusion/fixation and oxidation steps. With the dyeing plant in the configuration of FIG. 9 it is therefore possible to carry out two dyeing steps if the plant is used in line, or four dyeing steps if the return path 64 is also used.

(41) It should be noted that the ring system provided with the return path 64, compared to patent GB 1430154, is conceptually and technically applied differently. In fact, in addition to the dyeing processes described above, other variations are possible depending on the number of dyeing apparatuses 10 used, which can be one or even more than two. Of course, the indicative cycles of the dyeing processes above can be integrated with traditional manufacturing operations of denim fabric, such as caustic soda pre-treatment, pre-dyeing, over-dyeing, etc.

(42) It is also noted that each covering case 24, and consequently the shape and the capacity of the two dyeing groups 14 and 20 (which may comprise one or more dyeing tanks 34, 44) and of the intermediate oxidation or diffusion/fixation group 18 can be achieved in various ways according to the production or dyeing requirements. Therefore, a minimum or higher content of yarn 100 may be employed for dyeing and/or the diffusion/fixation and/or the oxidation of the dye, with or without the nitrogen seal outlet device 28 to make such a yarn 100 exit from the dyeing apparatus.

(43) By way of example, some of these possible variations of the dyeing apparatus 10, which all fall under the protection scope of the disclosure, are shown in the accompanying FIGS. 10 to 15. In particular, the apparatuses of FIGS. 10 and 11 are both configured to dye fabric rope warp chains. The apparatus in FIG. 12 is configured to dye fabric flat warp chains. The apparatus in FIG. 13 is ideal for the inclusion in standard dyeing plants for dyeing with sulphur black dye. The apparatuses in FIGS. 14 and 15 with the two dyeing groups 14 and 20 comprising a single tank suitably shaped, are very simple, inexpensive and small in size, which facilitates their inclusion in existing dyeing plants.

(44) It has thus been seen that the multifunctional continuous dyeing apparatus for warp chains according to the present disclosure achieves the objects described above. The multifunctional continuous dyeing apparatus for warp chains according to the present disclosure achieves the objects mentioned in the preamble of the description and, unlike the plants and processes used to date in dyeing with indigo, not only has greater operating flexibility but also allows significantly reducing the number of treatment tanks and, consequently, the costs of plants, the installed power, the volumes of the dyeing baths as well as production waste during batch changes.

(45) In case of use for dyeing in an inert environment, it should be noted that in order to have maximum flexibility over the end result in terms of corticality and fixation degree, in addition to the known physical and chemical variables, the apparatus above is also arranged to vary the bath-fiber contact time and the residence time in the diffusion/fixation group. The multifunctional dyeing apparatus according to the present disclosure further offers the possibility to dye small yarn batches, i.e. reduced yarn sizes, increasingly demanded by the market. It is in fact noted that in traditional plants, the minimum length of warp batches to dye is based on the length of the yarn which is the threading of the plant itself and, therefore, at every batch change the percentage of yarn to discard will be proportionately higher the shorter will be the batch.

(46) The multifunctional continuous dyeing apparatus for warp chains of the present disclosure thus conceived can be subjected to numerous modifications and variants, all falling within the same inventive concept; moreover, all details may be replaced with technically equivalent elements. In the practice, the materials used as well as shapes and sizes, may be any, according to the technical requirements.

(47) The scope of protection of the disclosure is therefore defined by the accompanying claims.