Dyeing machine and dyeing method using the same

Abstract

A description is provided of a dyeing machine comprising: a dyeing apparatus provided with a housing enclosing a dye compartment and an airtightly sealed opening allowing access to the dye compartment; a support frame that rotates within the dye compartment; at least one tank containing a dye bath; a hydraulic circuit hydraulically connected to each tank and the dyeing apparatus to supply the dye bath from each tank to the dye compartment or from the dye compartment to each tank; and a plurality of support devices for skeins and / or garments to be dyed. The support devices are mounted on the support frame and accessible via the opening. The hydraulic circuit comprises one or more circuits for supplying nitrogen and air, the circuits being hydraulically connected to each tank and the dye compartment to enable nitrogen to be supplied to each tank and the dye compartment. The present application also provides a method for dyeing skeins and / or garments with indigo using the dyeing machine.

Description

Technical Field

[0001] The present invention generally relates to machines for treating yarn and fabric, and in particular to machines for dyeing skeins and / or garments with indigo and other dyes in an environmentally sustainable manner. More specifically, the present invention relates to machines and methods for dyeing with indigo and other vat dyes, preferably operating in an inert environment under nitrogen.

[0002] For the sake of clarity and simplicity of description, the dyeing machine according to the invention will be described by way of non-limiting example with reference to the dyeing of hanks of yarn using indigo dye. However, it should be noted that, in addition to the above, the dyeing machine according to the invention is also suitable for dyeing any fiber hanks using suitable dyes of different categories, and it will be understood that, using a suitable internal rotating material carrier frame, the dyeing machine according to the invention is also suitable for dyeing ready-made garments, whether made of knitted fabric or fabric, such as socks, sweaters, jeans, etc. Background Art

[0003] For thousands of years, natural indigo, extracted by grinding various Indigo plants and various other plants common in India and Java, was the best blue for wool, linen, silk, and cotton. In 1883, the German chemical company BASF finalized the formula for indigo, and a few years later, BASF brought a new, much-lower-cost synthetic indigo to market, which quickly replaced natural indigo. However, in 1908, after the German chemical company CASSELLA discovered the blue dye "Hydron"—a blue dye that was easier to apply, had better fastnesses, and was significantly lower in cost—indigo was completely phased out within a few years.

[0004] However, the specific properties of indigo, namely the fact that after repeated washing its blue color tends to lighten until it becomes a brighter and brighter light blue, in contrast to the new "Hydron" blue which, on the other hand, tends to become dull, meant that about 50 years later, indigo regained popularity with the initial success of jeans, which went from being simple work clothes to being synonymous with leisure time, to the point that they rose to the ranks of high fashion and became a classic garment throughout the world.

[0005] Today, as in the past, due to changing social needs and the continuous evolution of fashion, there is a renewed need to dye yarn with indigo, a dye that is inseparable from jeans, in order to complete the production of new clothing, make it modern and accessible. This is because indigo is the only dye with the following specific properties: over time, and with various washes, it makes the shade of the produced garment lighter, as in the case of classic jeans, but still very bright, thus giving the produced garment a very pleasant appearance.

[0006] One of the characteristics of indigo dye that makes it unique is the specific dyeing method required to apply it to cotton yarn. This dyeing method has remained virtually unchanged for more than a hundred years since indigo dye was synthesized, from the time when plant dyes were used until now. Due to the relatively small size of the molecules of indigo dye and its low affinity for cellulose fibers, in order to apply indigo dye, indigo dye must not only be reduced in an alkaline solution (of the colorless compound), but also must be subjected to multiple dippings alternating with wringing in air and subsequent oxidation. In fact, medium or dark shades can only be obtained by subjecting the yarn to a first dyeing operation (consisting, in sequence, of dipping, squeezing and oxidation stages) followed by a number of overdyeing operations, all of which are repeated the more times the shade becomes darker and the greater the required color fastness.

[0007] However, while this method of work is easily applicable to the continuous dyeing of denim fabrics for the production of jeans – since it is carried out on a production line consisting of a series of dyeing tanks, each equipped with a device for squeezing and oxidation – it is not easy, or even very difficult, to apply to various garments made from hanks of yarn using conventional discontinuous dyeing machines of the so-called "batch" type. Needless to say, the complete absence of indigo dye for a long time, apart from jeans, coupled with the lack of interest in new specific uses, did not stimulate research and experimentation in this area.

[0008] Among the various types of cotton yarn and other fibers, the product that lends itself best to the discontinuous (batch) dyeing method with indigo is the hank-type product. Dyeing yarn in hank form is probably the oldest system (although the technology is constantly being modernized) and is still widely used with various types of dyes (excluding indigo) for various reasons and technical requirements.

[0009] In the past, in the case of indigo, hanks were dyed in wooden tanks, suspended on special rods shaped like an inverted omega, allowing them to be completely immersed in the dye bath to prevent oxidation. The position of the hanks on these rods was manually changed, and these rods were moved from one side of the tank to the other. When dyeing was complete, the hanks were wrung out and exposed to air to oxidize. These operations had to be repeated as many times as needed, depending on the desired shade.

[0010] Dyeing hanks is still in use. Hanks are products where the yarn is wound freely, gently, regularly, and extensively, preserving all of the yarn's properties. These qualities are highly valuable in the knitwear industry, especially for fine and delicate fibers. Furthermore, hanks are products where the yarn is wound in the form of loops, thus allowing the cotton hank to be stretched during the mercerizing process, a particularly important process in the knitwear and shirtmaking industries, using only specialized machinery.

[0011] Mercerizing, as it is commonly known in honor of its inventor, John Mercer, is a process whereby, through the action of concentrated caustic soda at low temperatures, cotton yarn undergoes considerable shrinkage which, if prevented, imparts a silky sheen to the fiber. In fact, the more intense the shortening of the yarn induced by the caustic soda, and the more effectively this shortening is prevented, the greater the sheen of the yarn obtained.

[0012] In addition to providing the yarn with a specific lustre, mercerizing also gives it greater mechanical strength by improving the elastic "coating" and, moreover, gives it the important property of being dyed more intensely than the same yarn without mercerizing, thus allowing significant savings in dye.

[0013] Due to all these specific properties, mercerized yarns are very important for the knitwear and shirtmaking industries. If they were also able to dye with indigo, this would offer a significant expansion in the supply of new products, which are in high demand in the fashion industry, and thus help the corresponding markets recover in times of crisis. If indigo-dyed yarns are well-fixed and, in particular, do not collect dust, even without mercerization, they are particularly valuable for the production of a wide variety of new, smooth, and finished fabrics and knitwear. Furthermore, in addition to conventional long velvets, other sportswear and knitted jeans could be offered, which are in high demand because they are far more convenient, easier to wear, and more comfortable than traditional types.

[0014] The machines currently available in the world for dyeing hanks consist almost exclusively of "cabinet" type machines, so called because of their vertical parallelepiped form, in which the hank, suspended on a series of rods with adjacent stops and on one or two levels, is completely immersed in the dye bath and is maintained in a two-way circulation, down / up and up / down, by means of a pump. These machines operate at full capacity, with an average ratio between the weight of the yarn and the volume of the dye bath of about 1 to 13. These machines are absolutely unsuitable for dyeing with indigo, as the main structure is difficult and requires many manual operations, resulting in very high costs and, above all, suboptimal quality results.

[0015] In fact, in order to be able to dye with indigo using the traditional process consisting of successive stages of impregnation, squeezing and oxidation, after the first dyeing operation, it is necessary to empty the cabinet, recover the dye bath, remove the skein, spin it, and oxidize the dye in air. The skein must then be reintroduced into the cabinet to repeat all the stages again in further processing until the desired shade is obtained. This clearly shows that, in current cabinet dyeing machines, it is practically impossible to dye a skein with indigo unless a single cycle is performed to obtain very light shades, requiring many manual operations and with sub-optimal quality results.

[0016] Based on this, although it may seem absurd, it must be admitted that the old manual system for dyeing indigo would have been simpler and less complicated than the modern system of dyeing in cabinet machines, where the hank is completely immersed in a tank and all operations are apparently automated. However, this is a system that would not be thought of in creation today.

[0017] Although not specifically designed for dyeing with indigo, two hank-dyeing machines were developed around 1890 / 1895 that modernized the older pot-type system, in which the dye bath was stationary and a rod, along with the hank, was manually moved and translated. While the dye bath was always stationary, these two dyeing machines placed the hank on a rod that was arranged in a spoke-like manner on a rotating hank carrier. One of these two machines was produced by the German textile engineering company ZITTAUER in the late 19th century. The other machine was described on page 691 of the Italian monthly magazine "LANIERA" in October 1987.

[0018] A third hank dyeing machine similar in design to the two machines described above is described in DE 855684C. However, in this dyeing machine, the hank carrier is divided into two parts. Besides being completely unsuitable for dyeing with indigo, like the two dyeing machines described above, the dyeing machine described in DE 855684C has a number of design and functional problems, namely:

[0019] - the dyeing machine has an unreasonable system for loading / unloading the hanks, which is carried out from above while the hanks are horizontal, which means that two long poles must be held in hand at the same time and therefore requires two operators, one on each side of the dyeing machine, who must be able to move on the lateral platform;

[0020] - the rods are designed to carry 16 hanks and are about 2 m long (in the dyeing cabinet, the largest rods are 1 m long and each rod supports 8 x 500 g hanks), making them difficult to maneuver, being heavy and requiring two operators to move;

[0021] - the large thickness determined by the seven rows of hanks housed in the two rotating parts of the dyeing machine leads to significant differences in the percentage of residual moisture between the individual hanks during the turning phase, due to the significant differences in the peripheral speed between the inner and outer hanks, which has a negative impact on the dyeing quality;

[0022] - a hank-carrying rod, usually consisting of a tube with a small cross-section, but 2 m long and holding 8 kg of dry yarn, which becomes very heavy when wet, will almost certainly bend during rotation rather than remain straight;

[0023] - At the end of dyeing, downtime is allowed for dripping: this is a serious mistake, since even after turning there will always be a difference in residual humidity between the high and low parts of the hank;

[0024] - the two thicker parts of the unidirectionally rotating hank have a greater influence on the stationary dye bath and prevent the necessary regular exchange of bath with fiber, which means that the uniformity of dyeing cannot be guaranteed;

[0025] - taking into account the fact that the dye bath actually occupies half the volume of the housing of the dyeing machine,

[0026] The ratio between the volume of the dye bath and the weight of the yarn is very high (perhaps about 20 to 1);

[0027] The dyeing machine does not have heating / cooling coils for the dye bath; however, since this is a dye bath with a relatively large volume, it would probably not be economical to use a cooling system to bring the temperature of the dye bath to 15°C, the temperature of maximum affinity for indigo dye, or to use an ultrasonic generator to further increase the color yield.

[0028] Even if the above-mentioned problems were overcome from an operational point of view, the dyeing machine described in document DE 855684 C still suffers from the same insurmountable problems as the other two dyeing machines mentioned above, which makes it completely unsuitable for dyeing with indigo. In fact, during the dyeing process, some of the spokes carrying the hank (in the two dyeing machines mentioned above) and one of the two hank-carrying parts (in the dyeing machine described in document DE 855684 C) remain in alternating contact with air and are therefore in a state of harmful oxidation of the bath used to dye the corresponding hank.

[0029] In file WO 96 / 17990A1 and JP S62 6966A, other dyeing machine has been described.Yet, these dyeing machines are all not suitable for dyeing hank or ready-made garment with indigo dyestuff fully.In fact, in the dyeing process, in these machines, most textile material to be dyed always keeps in contact with air alternately and is therefore in the state that corresponding dipping bath is carried out harmful oxidation.It should be pointed out that the dyeing machine of describing in file WO 96 / 17990A1 can not be used for industrial production because of its design and operating characteristics and the ad hoc system that hank is positioned.In addition, the dyeing machine of describing in file JP S62 6966A does not have the supporting device for the hank that stretches between two arms or does not have the supporting device for the hank that is suspended on the standard rod.Without these supporting devices, the yarn of the hank placed in the unit of the rotating basket that moves freely and rolls will become messy and tangled, thereby makes subsequent untying operation become impossible and therefore makes the use of yarn itself become impossible. In fact, the dyeing machine described in document JP S62 6966A appears to be a conventional rotary dyeing machine for garments, which uses the principles that have been commonly used in industrial and domestic washing machines for more than 50 years. Summary of the Invention

[0030] The object of the present invention is therefore to provide a machine for dyeing hanks of yarn and / or garments with indigo or other dyes in an environmentally sustainable manner, which machine makes it possible to eliminate the above-mentioned disadvantages of the prior art in an extremely simple, economical, ergonomic, ecological and particularly practical manner.

[0031] In detail, the object of the present invention is to provide a machine for dyeing hanks and / or garments with indigo, which allows the entire dyeing cycle to be carried out sequentially directly inside the machine and in an inert environment, offering a series of quality advantages not only economically but also in terms of fastnesses, fixation of the dyes and brightness of the dyeings.

[0032] Another object of the present invention is to provide a machine for dyeing hanks and / or garments with indigo which reduces the number of dyeing stages to a single stage.

[0033] Another object of the present invention is to provide a machine for dyeing hanks of yarn and / or garments with indigo which can be operated with the smallest possible amount of dye bath, so that the consumption of energy, water and chemical products (caustic soda and sodium sulfite) is drastically reduced, and thus the production costs are reduced.

[0034] Another object of the invention is to provide a machine for dyeing hanks of yarn and / or garments, with indigo and other vat dyes under nitrogen or with other types of dyes in contact with air, with or without internal recirculation and with or without upper sprays, which machine can operate with a very low ratio between the weight of the yarn and the volume of the dye bath with the bath closed, and with a material-carrying frame having one or two stages that rotates slowly and alternately in both directions.

[0035] Another object of the present invention is to provide a machine for dyeing hanks and / or garments with indigo, which machine can use a high concentration dye bath and also perform a unique dyeing cycle at low and / or high temperatures.

[0036] Another object of the present invention is to provide a machine for dyeing hanks and / or garments with indigo which allows the recovery of used dye baths containing indigo so that they can be reused after titration and replenishment of the various ingredients.

[0037] Another object of the present invention is to provide a machine for dyeing hanks and / or garments with indigo, which uses a dye bath of the smallest possible volume, making it possible to economically apply a system for cooling the dye bath itself to about 15° C., in order to exploit the maximum affinity with the fibers, and to apply an ultrasonic generator in order to further improve the color yield.

[0038] Another object of the present invention is to provide a machine for dyeing hanks of yarn with indigo, which machine is particularly suitable for mercerized yarns used in knitwear, shirt production and other special applications.

[0039] A further very important object of the present invention is to provide a machine for dyeing hanks with indigo or other dyes which uses the same hank-carrying bars as the dyeing cabinets according to the prior art and has the same vertical loading system, thereby resulting in an advantageous operational interchangeability with these dyeing cabinets.

[0040] These objects according to the present invention are achieved by providing a machine for dyeing hanks and / or garments with indigo or other dyes according to the embodiments of the present application.

[0041] The dyeing machine according to the invention is horizontal and is designed to dye hanks and / or garments with partially filled or reduced-volume dye baths under nitrogen or in contact with air (at atmospheric pressure or at static pressure), and comprises inside it one or more material-carrying frames (for the hanks on a standard rod, common to all dyeing cabinets according to the prior art) that rotate along a single axis at a variable speed and in two directions. Thus, the dyeing machine can carry out inside it a complete dyeing cycle with indigo as well as with other types of dyes.

[0042] Dyeing machine according to the present invention does not have any shortcoming among the above-mentioned shortcomings of dyeing machine of known type, because dyeing machine according to the present invention operates in an inert environment (preferably under nitrogen) in a reasonable, ergonomic and sustainable mode of environment.This dyeing machine operates under the specific conditions of inert environment (preferably under nitrogen) with the very low ratio between the weight of hank and the volume of dye bath, this fact that is approximately equal to 1 to 4 ratio makes in the inside of this dyeing machine not only can use traditional operating method to dye completely, but also can dye with the process of innovation, the process of described innovation is single-stage and / or repeatable, does not have intermediate oxidation and at low temperature and / or high temperature with the independent special operating cycle of high concentration dye bath, which can not be carried out on traditional dyeing machine.All of these are very fast and carry out in the sustainable mode of environment.

[0043] The dyeing machine according to the invention also has the practical advantage of using the same hank-carrying rods as are commonly used in all cabinet dyeing machines according to the prior art, so that the dyeing machine according to the invention can operate in perfect coordination with all cabinet dyeing machines according to the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The characteristics and advantages of the machine for dyeing hanks and / or garments according to the invention will become more apparent from the following description given by way of non-limiting example with reference to the accompanying schematic drawings in which:

[0045] Figure 1 is a schematic illustration in vertical cross-section of a first embodiment of a machine for dyeing hanks of yarn and / or garments according to the invention, the machine being particularly designed for dyeing with indigo in an inert environment;

[0046] Figure 2 yes Figure 1 Schematic diagram of a vertical longitudinal section of only the dyeing apparatus of the machine in FIG, in which dyeing apparatus is adapted, for example, to rotate a single rotary support frame for accommodating a hank-carrying rod;

[0047] Figure 3 yes Figure 1 Schematic diagram of a vertical longitudinal section of only the dyeing apparatus of the machine in FIG, in which dyeing apparatus is adapted, for example, to rotate two rotating support frames for accommodating hank-carrying rods;

[0048] Figure 4A and Figure 4B is a schematic diagram in vertical cross-section of two possible variants of a machine for dyeing hanks of yarn and / or garments according to the invention, wherein the supporting frame is designed to accommodate two different types of supporting means for the garments; and

[0049] Figure 5 is a schematic illustration in vertical cross-section of a second embodiment of a machine for dyeing hanks and / or garments according to the invention, the machine being particularly designed for dyeing in air with dyes other than indigo. DETAILED DESCRIPTION

[0050] It should be noted that the following description and the accompanying drawings do not describe many of the components, accessories, and instruments that are typically present in all dyeing machines, as these are well known to those skilled in the art, such as, for example, dye bath level regulators, heat regulation units, preparation containers, units for recovering the dye bath and supplying auxiliary products, automatic metering systems, command and control instruments, etc. It should also be noted that the accompanying drawings show hydraulic circuits provided with corresponding pumps and valves, which, since they are well known to those skilled in the art, will not be described in detail below.

[0051] The accompanying drawings show two possible embodiments of a machine for dyeing skeins of yarn and / or garments according to the invention. The dyeing machine is designated as a whole by the reference numeral 10 and is designed for dyeing skeins of yarn and / or garments with indigo and other vat dyes in an inert atmosphere, preferably under nitrogen, and for dyeing skeins of yarn and / or garments with other types of dyes in air.

[0052] The dyeing machine 10 comprises at least one dyeing device 12, which is provided with:

[0053] a housing 18 enclosing at least one dye compartment 20; and

[0054] at least one hermetically sealed opening 22 provided on said housing 18 and allowing access to the dye compartment 20 .

[0055] The dyeing machine 10 further comprises at least one support frame 14 which is mounted for rotation within the dye compartment 20 and is designed to rotate about a central rotation axis A, which is substantially horizontal and passes through the rotation pin 16, by means of at least one rotation pin 16. The rotation of the support frame 14 can be controlled in a known manner by one or more electric motors 58 or by other motion means suitable for the purpose.

[0056] The dyeing machine 10 also includes at least one tank 24, 26 ( Figure 1 ) or 44, 46( Figure 5 ), said tanks comprising at least one dye bath B and at least one hydraulic circuit 28 hydraulically connected to each tank 24, 26 or 44, 46 and to the dyeing apparatus 12 for supplying dye bath B from each tank 24, 26 or 44, 46 to the dye compartment (20), or supplying dye bath B from the dye compartment (20) to each tank 24, 26 or 44, 46. The dyeing machine 10 further comprises a plurality of supporting devices 30, 32, 34 for hanks and / or garments, said devices being mounted on the support frame 14 and accessible via the opening 22.

[0057] Both the housing 18 and the support frame 14 preferably have a circular form in a vertical cross section, i.e. a cross section taken along a plane orthogonal to the central axis of rotation A of the support frame 14, so that the housing 18 has a cylindrical front wall and the dye compartment 20 therefore has a cylindrical form. Each opening 22 is provided in the cylindrical front wall of the housing 18, and the support means 30, 32, 34 are arranged on the support frame 14 according to a configuration preferably circumferential with respect to the central axis of rotation A, and said means are placed near the inner surface of the cylindrical front wall of the housing 18, for example at Figure 1 、 Figure 4A 、 Figure 4B and Figure 5 As shown in .

[0058] Each support frame 14 is bounded by a pair of preferably circular lateral walls 36, 38 that are substantially flat, opposite each other and arranged orthogonally relative to the central axis of rotation A. For example, Figure 2 A dyeing apparatus 12 is shown which is provided with a single support frame 14 (single-stage configuration). Figure 3 The dyeing apparatus 12 is shown as being provided with two different support frames 14 that are adjacent to one another in the direction of the central axis of rotation A (having a two-stage configuration). However, it is not excluded that the dyeing apparatus 12 is provided with three or more different support frames 14 that are always arranged adjacent to one another in the direction of the central axis of rotation A.

[0059] Preferably, each opening 22 has a width, measured along the central axis of rotation A, that is substantially equal to the distance L between the two lateral walls 36, 38 of each support frame 14. In other words, each opening 22 is "full front" to facilitate the operation of loading and unloading hanks and garments into and from the dyeing apparatus 12.

[0060] exist Figure 1 、 Figure 2 、 Figure 3 and Figure 5 In the embodiment of the present invention, the dyeing device 10 is designed to dye hank yarn. Therefore, each of the supporting devices 30 is composed of a bracket that supports a plurality of hank yarn carrier rods 40 to dye the hank yarn. On the other hand, in Figure 4A and Figure 4B In the variant, the dyeing machine 10 is designed to dye finished garments. Therefore, each of the supporting devices 32, 34 is formed by a perforated compartment or container provided with at least one opening 42. Each perforated compartment or container 32, 34 is designed to receive a finished garment and dye the finished garment by means of a dye bath B passing through the holes provided in the perforated compartment or container 32, 34.

[0061] By way of example only, Figure 1 、 Figure 2 、 Figure 3 and Figure 5 In the embodiment of the dyeing machine 10 designed to dye hanks, each support frame 14 can have one or two levels. Therefore, each support frame 14 is preferably designed to include six brackets 30, which are arranged in a "hexagonal" configuration in the circumferential direction (e.g., Figure 1 and Figure 5 ), and each bracket 30 supports three or four rows of hank carrier rods 40.

[0062] According to the invention, the hydraulic circuit 28 comprises one or more nitrogen and air supply circuits 50 hydraulically connected to each tank 24, 26 and to the dye compartment 20 having a cylindrical form, so as to be able to supply nitrogen N to each tank 24, 26 and to the dye compartment 20. Unlike the aforementioned dyeing machines according to the prior art, this technical feature makes it possible to dye the hanks and / or the garments inside the dye compartment 20 with indigo and other vat dyes in an inert environment.

[0063] Two different embodiments of the dyeing machine 10 - Figure 1 One embodiment is shown in Figure 5 Another embodiment is shown in - the difference actually lies in the dyeing method and the type of dye bath B used. Figure 1 The embodiment of the dyeing machine 10 in is designed to dye with indigo and other vat dyes in an inert environment and under nitrogen. Therefore, the dyeing machine 10 includes a first airtight sealed tank 24, which contains an indigo-based dye bath B and the necessary amount of nitrogen N, and a second airtight sealed tank 26, which is hydraulically connected to the first airtight sealed tank 24 and serves as an auxiliary tank for the indigo-based dye bath B and the necessary amount of nitrogen N. In this embodiment of the dyeing machine 10, each nitrogen and air supply circuit 50 is hydraulically connected to the first airtight sealed tank 24 and the second airtight sealed tank 26. In addition, in this embodiment of the dyeing machine 10, the dye compartment 20 having a cylindrical form can be provided with at least one chamber 54 in its interior, which serves as a reduction plenum chamber for the volume of nitrogen N contained in the dye compartment 20 having a cylindrical form.

[0064] on the other hand, Figure 5 The embodiment of the dyeing machine 10 in FIG. 1 is designed for dyeing in air with a dye other than indigo. Therefore, the dyeing machine 10 includes a first tank 44, which operates in air and contains a bath B of a dye other than indigo, and a second tank 46, which operates in air and is hydraulically connected to the first tank 44, which operates in air and serves as an auxiliary tank for the bath B of a dye other than indigo. Therefore, in this embodiment of the dyeing machine 10, nitrogen and the air supply circuit 50 are not used.

[0065] Independent of this embodiment, the dyeing machine 10 can include at least one recirculation loop 48 for the dye bath B housed in the dye compartment 20 with a cylindrical form. The dyeing machine 10 can also include one or more cascade sprayer devices 52, which are hydraulically connected to the dyeing apparatus 12 by means of a hydraulic circuit 28, and which are designed to spray the dye bath B directly into the dye compartment 20 with a cylindrical form. The dyeing apparatus 12 and / or at least one tank in the tank 24, 26 can also be provided with a device 56 for thermally regulating the dye bath B. These devices 56 for thermal regulation can be composed of one or more heating and / or cooling coils of the dye bath B. The dyeing apparatus 12 can finally be provided with one or more ultrasonic generators 60 to further improve the color yield.

[0066] Thus, the dyeing machine 10 is designed to immerse the hank or garment in the dye bath B, which occupies the lower part of the dye compartment 20. Without the dye bath B, the dyeing machine 10 can also rotate directly and, with nitrogen N exhausted and air drawn in, oxidize the hank or garment by means of the rotation of the support frame 14 about its own central rotation axis A. Due to the specific design of the dyeing machine 10, the dyeing machine 10 can actually dye with a very low ratio between the weight of the hank and the volume of the dye bath B, approximately equal to 1 to 4, compared to the ratio of 1 to 13 between the weight of the hank and the volume of the dye bath B in dyeing cabinets according to the prior art, and the dyeing machine 10 can rotate and oxidize the dyed hank and / or garment directly inside the dyeing machine 10 itself.

[0067] The dyeing machine 10 can also be used for dyeing in an inert environment using hank-carrying rods 40 having the same measurements as conventional cabinet dyeing machines and / or hank-carrying rods 40 from conventional cabinet dyeing machines (this is a special and advantageous ecological technology described in documents EP 1771617 B1 and EP 1971713 B1 and document WO 2017 / 208134 A1 in the name of the same applicant). This interchangeability of the hank-carrying rods 40 is very important and extremely convenient because, in order to significantly increase productivity, this interchangeability allows the dyeing machine 10 to be used only for the actual dyeing phase of the operating cycle, while on the other hand, the remaining initial operations (absorption, soaking, etc.) and final operations (washing, soaping, softening, etc.) can also be carried out in a conventional cabinet dyeing machine.

[0068] A particularly preferred structural form of the dyeing machine 10 and of the rotating support frame 14 of the dyeing machine 10, i.e. provided with six individual support devices 30 of relatively narrow thickness and three or four rows of hank-carrying rods 40, is designed such that:

[0069] - capable of sequential operation, wherein one of the six rotary supports 30 filled with hank-carrying rods 40 is completely immersed in the dye bath B of various chemical products and water in the smallest possible volume of the dyeing machine 10 (also with the advantage of a considerable reduction in energy consumption);

[0070] - operating in an inert atmosphere, under nitrogen N, so that the dye bath B present in the (unsubmerged) hanks contained in the other five rotating supports 30 does not oxidize, but continues the action of diffusion and fixation of said dye bath B in the fibers;

[0071] - operated by a slow, variable and bidirectional rotation of the support frame 14,

[0072] To ensure optimal exchange between dye bath and fiber;

[0073] - due to the reduced volume of the gas delivery chamber 54, the volume of nitrogen N in the dye compartment 20 is reduced to only the outer crown of the dye compartment 20, thereby reducing the consumption of nitrogen N by 25%, and

[0074] It also has the advantage of shortening the time of inertization;

[0075] - the dyeing can be carried out flexibly according to the needs and with variable capacity, i.e. the dyeing can be carried out with hanks which are equally well positioned in the support devices 30 in six (that is to say all), four, three or only two support devices;

[0076] - easy and ergonomic loading / unloading of the hank-carrying bar 40 by means of the lateral opening 22 , without the need for a platform and / or other lifting equipment by a single operator;

[0077] After the final dewatering, a substantially uniform residual moisture content is ensured between the hanks suspended on the outside and the inside of each of the supporting means 30 of the supporting frame 14 .

[0078] In addition to the specific characteristics mentioned above, the fact that the operation is carried out in an inert environment, preferably under nitrogen, makes it possible to modernize the known operating cycle for dyeing with indigo, which is basically composed of three operating stages repeated several times (impregnation of the hank with the leuco compound, elimination of the excess dye bath contained in the hank, and oxidation of the dyed yarn), and to add a fourth operating stage, that of diffusion / fixation of the leuco compound in the inert environment. Moreover, by operating under nitrogen, that is, in an inert environment, the dye bath B circulating from the dye bath B, which impregnates the hank held by the support device 30, is not only not oxidized, but, since it remains in the state of the leuco compound, it continues its diffusion and fixation in the fiber.

[0079] Operating under nitrogen not only significantly reduces operating time but also enables an innovative single-stage dyeing cycle with high dye bath concentrations and temperatures, reducing caustic soda and sodium sulfite consumption by 50% to 80%. Under nitrogen, the chemical reduction of indigo is complete and perfect, and the colorless compound is broken down into nanometer-sized particles. Compared to traditional systems, this feature enhances the dyeing ability of indigo, improves indigo penetration, and strengthens its fixation on fibers, as well as significantly saving washing water and achieving excellent results in terms of fastness, strength, and brightness – essential properties of yarns used in shirt production and knitwear.

[0080] A further technical improvement is provided by the very small volume of the dye bath B, which allows the economical use of heat conditioning devices 56. In particular, these heat conditioning devices 56 can be cooling devices which can, for example, cool the dye bath B to about 15° C. At this temperature, the indigo dye has a maximum affinity for the cellulose fibers, resulting in a better color yield, which can be further increased by using one or more ultrasonic generators 60.

[0081] The dyeing machine 10 according to the invention makes it possible to implement an innovative dyeing method comprising the following single-stage operating cycle, which is repeatable and fully automated. However, this dyeing method should be considered indicative and not mandatory, as it can be adapted to the specific production requirements and the composition of the color mixing room and / or other specific equipment.

[0082] After the entire amount of dye bath B required for dyeing a single batch or multiple batches constituting the entire yarn has been prepared in the first preparation tank 24, the determined amount of dye bath B required for the batch is transferred to the second auxiliary tank 26. The following steps are then taken:

[0083] a) loading the hank carrier rod 40 with the vertically positioned dry hank (which can be pre-treated directly or in a dyeing cabinet according to the prior art) into the supporting device 30 positioned in the dye compartment 20 through the convenient side opening 22 with a single operator on the ground;

[0084] b) inertizing the dye compartment 20 (and therefore the yarn) and the second auxiliary tank 26, wherein,

[0085] The necessary amount of dye bath B can be delivered to the second auxiliary tank 26 in advance, so that the dye bath B is kept in internal recirculation and under nitrogen N;

[0086] c) when a preset residual oxygen value is reached in the dye compartment 20, the internal recirculation in the second auxiliary tank 26 is blocked and the transfer of the dye bath B into the lower part of the dye compartment 20 is started, and the support frame 14 is rotated slowly and alternately in both directions;

[0087] d) dyeing the yarn under the necessary conditions and within a predetermined time (with or without internal recirculation of the dye bath B and with or without activation of the upper cascade spray device 52), also while slowly and alternately rotating the support frame 14 in both directions;

[0088] e) when the processing time has elapsed, the rotation of the support frame 14 is stopped and the dye bath B is transferred to the second auxiliary tank 26;

[0089] f) starting to rotate the support frame 14 at a preset speed for a predefined period of time to drain the interstitial dye bath from the hank and to recycle the interstitial dye bath itself into the second auxiliary tank 26; g) optionally, holding the hank under nitrogen N for a predefined period of time and rotating the support frame 14 slowly and alternately in both directions to diffuse the dye in the fiber /

[0090] fixed;

[0091] h) Optionally, repeat operations c), d), e), f), and g);

[0092] i) rotating the skein for a predefined period of time and recovering the extracted dye bath B into the second auxiliary tank 26;

[0093] j) isolating the dye compartment 20 from the hydraulic circuit 28 for supplying / regulating nitrogen N;

[0094] k) rendering the dye compartment 20 inert;

[0095] l) admitting air to the interior of the dye compartment 20 and rotating the support frame 14 slowly and alternately in both directions for a predefined period of time to obtain oxidation of the dye;

[0096] m) carrying out any washing operation and / or final treatment of the hank, with or without intermediate rotation (said washing operation and / or final treatment can also be carried out in a dyeing cabinet according to the prior art in order to increase the productivity of the dyeing machine 10);

[0097] n) optionally, performing a final rotation operation (if point m was performed);

[0098] o) Unloading the hanks from the support device 30 for final drying of these hanks.

[0099] For ecological and economic purposes, it should be noted that the spent dye bath obtained from dyeing each batch can be recycled into a suitable container (not shown) and reused after titration and replenishment of the various components. It will be understood that, with appropriate adjustments and simplifications, the operating cycle described can also be advantageously used with dyes other than indigo. It should also be noted that, in addition to the characteristics and advantages associated with dyeing only with indigo, all the specific characteristics of the new machine and the technical, economic and ecological advantages described above are also largely applicable to dyeing a wide range of fibers with dyes of other types.

[0100] In fact, dyeing machine 10 according to the present invention has completely changed the existing system for dyeing hank in dyeing cabinet, different from these dyeing cabinets, dyeing machine 10 allows to carry out whole operation cycle in the inside of this dyeing machine 10, and does not need to move material, makes the ratio between the weight of hank and the volume of dye bath significantly reduce, and makes energy consumption, labor and operating time, chemical product and especially water reduce.All these are reasonably, simply, conveniently and especially economically and carry out in the sustainable mode of environment.Compared with the dyeing cabinet according to prior art, dyeing machine 10 according to the present invention is simplified in structure, and although more complete, convenient and reasonable, the economic cost of this dyeing machine 10 is but significantly reduced.

[0101] The dyeing machine 10 according to the invention is also characterized by a particular versatility and flexibility of operation, since, with the rotation of the support frame 14, it can also dye and treat garments made of knitted fabric or fabric, with all the advantages mentioned above. These processing operations are increasingly in demand, since they can be carried out in short periods on untreated garments already in stock, allowing for rapid delivery and thus keeping pace with the increasingly rapid changes in fashion.

[0102] It should be noted that the dyeing machine 10 according to the invention, since it is essentially composed of equipment having a cylindrical form, whereas the dyeing cabinets according to the prior art have a parallelepiped form, is advantageous and has much lower economic costs with reference to the structure of the alternative solution operating under static pressure, which is a necessary condition for being able to dye hanks and / or garments made of synthetic fibers, requiring a dye bath temperature close to 120° C. / 130° C. In fact, since the dyeing machine 10 is cylindrical, it can withstand higher pressures than those obtained in a dyeing cabinet having a parallelepiped form and can therefore reach the above-mentioned temperatures (120° C. / 130° C.) and performance levels far greater than the maximum values ​​of 108° C. / 110° C. that can be achieved in a dyeing cabinet usually pressurized to 0.4 bar.

[0103] It has thus been shown that the machine for dyeing hanks and / or garments according to the invention achieves the aforementioned objects and in particular offers the following advantages:

[0104] - Single machines for dyeing garments and / or hanks on standard rods with indigo under nitrogen;

[0105] - the ratio between the volume of the dye bath and the weight of the yarn is 2 / 3 lower than that of the dyeing cabinets according to the prior art;

[0106] - Recovery and reuse of dye baths containing indigo;

[0107] -Perform the complete dyeing cycle directly in-house;

[0108] - Ecological dyeing cycles with indigo and vat dyes under nitrogen;

[0109] - Better diffusion and fixation of dyes on the fibers;

[0110] - the dye bath with indigo can be cooled and ultrasound activated to increase the already high color yield;

[0111] - A significant reduction in the consumption of caustic soda and sodium sulfite in the case of indigo or other vat dyes;

[0112] - Reduce energy consumption;

[0113] - Reduce water consumption;

[0114] - Significantly reduce sulfites and sulfates in wastewater;

[0115] - Reduce dyeing time;

[0116] - Reduce production costs;

[0117] - A single-stage cycle can be performed with a dye bath having a high indigo concentration and high temperature;

[0118] - Maximum operational flexibility;

[0119] - Dyeing can be done with dyes of other types than indigo (in air);

[0120] -Can be dyed simply with variable capacity;

[0121] - pre-treatment and post-treatment stages can be carried out in dyeing cabinets according to the prior art;

[0122] - Garments made of knitted fabrics or woven fabrics can be dyed;

[0123] - It is possible to operate with a bath at a temperature above 100° C. under static pressure.

[0124] The machine for dyeing hanks of yarn and / or garments thus designed is in any case susceptible of numerous modifications and variations, all of which are within the scope of the same inventive concept; moreover, all the details can be replaced by technically equivalent elements. In practice, any material, form and size may be used according to technical requirements.

[0125] Therefore, the scope of protection of the present invention is defined by the appended claims.

Claims

1. A dyeing machine (10) for hanks of yarn and / or garments, comprising: - at least one dyeing device (12), said dyeing device (12) being provided with: - a housing (18) enclosing at least one dye compartment (20); as well as - at least one hermetically sealed opening (22) provided on the housing (18) and allowing access to the dye compartment (20); at least one supporting frame (14) mounted to rotate inside the dye compartment (20) and designed to rotate about a central rotation axis (A) by means of at least one rotation pin (16), the central rotation axis (A) being horizontal and passing through the rotation pin (16); - at least one tank, at least one of said tanks containing at least one dye bath (B); at least one hydraulic circuit (28), at least one hydraulic circuit (28) being hydraulically connected to at least one of the tanks and the dyeing apparatus (12) for supplying at least one of the dye baths (B) from at least one of the tanks to the dye compartment (20), or supplying at least one of the dye baths (B) from the dye compartment (20) to at least one of the tanks; as well as - a plurality of supporting devices for the hank and / or the garment, the supporting devices being mounted on the supporting frame (14) and being accessible via the opening (22), wherein both the shell (18) and the support frame (14) have a circular form in a vertical cross-section, i.e. a cross-section obtained along a plane orthogonal to the central rotation axis (A), so that the shell (18) has a cylindrical front wall and the dye compartment (20) has a cylindrical form, wherein the opening (22) is provided on the cylindrical front wall, and wherein the support device is placed near the inner surface of the cylindrical front wall, the dyeing machine (10) is characterized in that at least one of the hydraulic circuits (28) includes one or more nitrogen and air supply circuits (50) for supplying nitrogen and air, and one or more of the nitrogen and air supply circuits (50) are hydraulically connected to at least one of the tanks and at least one of the dye compartments (20) to supply nitrogen (N) to at least one of the tanks and at least one of the dye compartments (20).

2. The dyeing machine (10) according to claim 1, characterized in that The support means are arranged on the support frame (14) according to a configuration that is circumferential relative to the central axis of rotation (A).

3. The dyeing machine (10) according to claim 1, characterized in that Each support frame (14) is bounded by a pair of circular lateral walls (36, 38) which are flat, opposite each other and arranged orthogonally with respect to the central axis of rotation (A).

4. The dyeing machine (10) according to claim 3, characterized in that Each opening (22) has a width, measured along the central axis of rotation (A), which is equal to the distance between the two lateral walls (36, 38) of each support frame (14).

5. Dyeing machine (10) according to any one of claims 1 to 4, characterized in that Each of the supporting devices is composed of a bracket that supports a plurality of hank carrier rods (40) for dyeing the hank.

6. Dyeing machine (10) according to any one of claims 1 to 4, characterized in that Each of the supporting means is constituted by a perforated container or compartment provided with at least one perforated door (42), wherein each perforated container or compartment is designed to receive the garment.

7. Dyeing machine (10) according to any one of claims 1 to 4, characterized in that The dyeing machine (10) comprises: - a first hermetically sealed tank (24) containing an indigo-based dye bath (B) and a necessary amount of nitrogen (N); and - a second hermetically sealed tank (26) which is hydraulically connected to the first hermetically sealed tank (24) and serves as an auxiliary tank for the indigo-based dye bath (B) and the necessary amount of nitrogen (N).

8. The dyeing machine (10) according to claim 7, characterized in that The dye compartment (20) having a cylindrical form is provided with at least one chamber (54) inside the dye compartment (20), and the at least one chamber (54) serves as a gas supply chamber for reducing the volume of nitrogen (N) contained in the dye compartment (20) having a cylindrical form.

9. Dyeing machine (10) according to any one of claims 1 to 4, characterized in that The dyeing machine (10) comprises: - a first tank (44) operating in air, said first tank (44) containing a dye bath (B) different from indigo; and - a second tank (46) operating in air, said second tank (46) being hydraulically connected to said first tank (44) operating in air and serving as an auxiliary tank for said dye bath (B) other than indigo.

10. Dyeing machine (10) according to any one of claims 1 to 4, characterized in that The dyeing machine (10) comprises at least one recirculation circuit (48) for the dye bath (B) contained in the dye compartment (20) having a cylindrical form.

11. Dyeing machine (10) according to any one of claims 1 to 4, characterized in that The dyeing machine (10) comprises one or more cascade sprayer devices (52) which are hydraulically connected to the dyeing apparatus (12) via the hydraulic circuit (28) and are designed to spray the dye bath (B) directly into the dye compartment (20) having a cylindrical form.

12. Dyeing machine (10) according to any one of claims 1 to 4, characterized in that The dyeing apparatus (12) and / or at least one of the tanks is provided with a thermal conditioning device (56) for thermally conditioning the dye bath (B).

13. Dyeing machine (10) according to any one of claims 1 to 4, characterized in that The dyeing device (12) is provided with one or more ultrasonic generators (60) to further improve color rendering.

14. A method for dyeing hanks of yarn and / or garments with indigo using a dyeing machine (10) according to any one of claims 1 to 13, said method comprising a preliminary stage of transferring the necessary dye bath (B) from a first hermetically sealed tank (24) to a second hermetically sealed tank (26), said method further comprising: The following stages are included: a) loading the hank and / or the garment into the supporting device; b) rendering the dye compartment (20) and the second hermetically sealed canister (26) inert; c) when a predetermined value of residual oxygen is reached in the dye compartment (20), transferring the dye bath (B) to the lower part of the dye compartment (20) and rotating the support frame (14) slowly and alternately in two directions; d) dyeing the hank and / or the garment for a predetermined time and likewise rotating the support frame (14) slowly and alternately in two directions; e) when the predetermined time has elapsed, stopping the rotation of the support frame (14) and transferring the dye bath (B) into one of the second hermetically sealed tanks (26); f) commencing rotation of the support frame (14) at a predefined speed for a predetermined period of time to expel the interstitial dye bath from the hank and / or the garment and to recover the interstitial dye bath into one of the second hermetically sealed tanks (26); h) If necessary, repeat stages c), d), e) and f); i) rotating the hank and / or the garment for a predetermined period of time and recovering the extracted dye bath (B) into one of the second hermetically sealed tanks (26); j) isolating the dye compartment (20) from the hydraulic circuit (28); k) rendering the dye compartment (20) inert; 1) introducing air into the dye compartment (20) and rotating the support frame (14) slowly and alternately in two directions for a predetermined period of time to obtain oxidation of the dye; as well as m) unloading the hank and / or the garment from the supporting device for final drying of the hank and / or the garment, The process is characterized in that the ratio between the weight of the skein and / or the garment and the volume of the dye bath (B) is equal to 1 to 4.

15. The method according to claim 14, further comprising, after stage f) and before stage h), stage g) of holding the skein and / or the garment under nitrogen (N) for a predetermined period of time and rotating the support frame (14) slowly and alternately in two directions to diffuse / fix the dye in the fibers; and, if necessary, repeating stages c), d), e), f), g) in stage h).

16. The method according to claim 14 or 15, further comprising, after stage 1) and before stage m), the following stages: n) washing and / or finishing the hank and / or the garment with or without intermediate turning; o) performing a final turning of the hank and / or the garment.

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