Machine for dyeing hank yarns and / or garments in environmentally sustainable manner with indigo and other dyes

Abstract

There is provided a description of a dyeing machine comprising: a dyeing device provided with a housing enclosing a dye compartment and a hermetically sealed opening allowing access to the dye compartment; a support frame rotating within the dye compartment; at least one tank containing a dye bath; a hydraulic circuit hydraulically connected to each tank and the dyeing device; and a plurality of support devices. The support device is mounted on the support frame and accessible via the opening. Both the housing and the support frame have a cross-section in a preferably circular form, such that the housing has a cylindrical front wall and the dye compartment has a cylindrical form. An opening is provided on the cylindrical front wall of the housing, a support device is arranged on the support frame according to a configuration preferably in a circumferential direction with respect to a central axis of rotation of the support frame, the device being placed near an inner surface of the cylindrical front wall of the housing. A hydraulic circuit is hydraulically connected to each tank and dye compartment to be able to supply nitrogen to each tank and dye compartment.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 202180067646.X, filed on September 14, 2021, entitled "Dyeing Machine and Method of Dyeing Using a Dyeing Machine". Technical Field

[0002] This invention generally relates to machines for treating yarns and fabrics, and more particularly, to machines for dyeing skeins and / or garments with indigo and other dyes in an environmentally sustainable manner. More specifically, this invention relates to machines and methods for dyeing, preferably operated in an inert environment under nitrogen atmosphere using indigo and other vat dyes.

[0003] To make the description clearer and simpler, the dyeing machine according to the invention will be described by way of non-limiting embodiments with reference only to the dyeing of skeins using indigo dye. However, it should be noted that, in addition to the foregoing, the dyeing machine according to the invention is also suitable for dyeing any fiber skeins using suitable different classes of dyes, and it will be understood that, with the use of a suitable internally rotating material carrier frame, the dyeing machine according to the invention is also suitable for dyeing garments such as socks, sweaters, jeans, etc., whether made of knitted or woven fabrics. Background Technology

[0004] For millennia, natural indigo, extracted by grinding various species of the Indigo genus and 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 launched a new synthetic indigo with significantly reduced costs, which quickly replaced the natural type. However, in 1908, the German chemical company CASSELLA discovered the blue dye "Hydron"—which was easier to apply, had better fastness, and was significantly cheaper—and within a few years, indigo was completely phased out.

[0005] However, the specific characteristics of indigo—that its blue color tends to lighten with repeated washing until it becomes an increasingly bright light blue—contrast with the new "Hydron" blue, which tends to become dull on the other hand, meant that about 50 years later, indigo regained favor with the initial success of jeans, which transformed from simple workwear into a synonym for leisure time, elevating them to the ranks of high fashion and making them a classic garment worldwide.

[0006] Today, as in the past, due to changing social needs and the continuous development of fashion, there is once again a need to use indigo, an essential dye for jeans, to dye yarn in order to produce new garments and modernize and make their production more accessible. This is because indigo is the only dye with the following specific characteristics: over time, after various washes, indigo causes the produced garments, as in the case of classic jeans, to become lighter in color, yet still very bright, thus giving the garments a very pleasing appearance.

[0007] One of the defining characteristics of indigo dye is the specific dyeing method required to apply it to cotton yarn. From the era of plant dyes to the present day, for over a century since the synthesis of indigo dye, this dyeing method has remained virtually unchanged. Because indigo dye molecules are relatively small and have a low affinity for cellulosic fibers, its application requires not only reduction in an alkaline solution (a colorless compound) but also multiple impregnations alternating with wringing in air and subsequent oxidation. In fact, only by performing a primary dyeing operation on the yarn (consisting of impregnation, extrusion, and oxidation stages in sequence), followed immediately by multiple over-dyeing operations, can a medium or dark hue be obtained; the more over-dyeing operations, the deeper the hue and the greater the required colorfastness.

[0008] However, while this method is readily applicable to the continuous dyeing of denim fabrics for the production of jeans—because it is carried out on a production line consisting of a series of dyeing tanks, each equipped with devices for compression and oxidation—the same method is not easily, or rather, very difficult to apply to the various garments made from skeins using traditional, non-continuous dyeing machines of the "batch" type. Undoubtedly, the complete lack of use of indigo dye outside of jeans for a long time, coupled with a lack of interest in new specific applications, did not stimulate research and experimentation in this area.

[0009] Of the wide variety of cotton yarns and other fibers, the skein type is best suited for a non-continuous (batch) dyeing method with indigo. Dyeing yarns in skein form is perhaps the oldest system (although the technology has been modernized), and it is still widely used in practice for various reasons and technical requirements, utilizing a wide range of dyes (excluding indigo).

[0010] In the past, in the case of indigo, skeins were dyed in wooden vats, suspended on special rods shaped like inverted omega poles for immersion, ensuring complete submersion in the dye bath to prevent oxidation. The position of the skeins on these rods was manually changed, with the rods being moved from one side of the vat to the other. When dyeing was complete, the skeins were wrung out and exposed to air for oxidation. These processes had to be repeated multiple times depending on the desired color.

[0011] Dyeing skeins is still in use. Skeins are products where yarn is freely, gently, regularly, and extensively wound to maintain all the properties of the yarn. These qualities are highly valuable in the field of knitwear, especially for fine and delicate fibers. Furthermore, skeins are products where yarn is wound in loops, and therefore, under conditions uniquely aided by specific machinery, allow cotton skeins to be tensioned during mercerizing, a process particularly important for knitwear and shirt production.

[0012] As is commonly known in honor of its inventor, John Mercer, mercerization is a process in which cotton yarn undergoes considerable shrinkage at low temperatures under the action of concentrated caustic soda. If this shrinkage is prevented, the fiber acquires a silky luster. In fact, the more intense the yarn shrinkage caused by caustic soda, and the more effectively this shrinkage is prevented, the better the luster of the yarn obtained.

[0013] In addition to giving the yarn a specific luster, mercerizing also gives the yarn greater mechanical strength by improving the elastic "coating". Furthermore, mercerizing gives the yarn a more intense dyeing effect compared to the same yarn without mercerizing, thus resulting in significant dye savings.

[0014] Due to all these specific characteristics, mercerized yarn is crucial for the knitwear and shirt manufacturing sector. If this sector could also be dyed with indigo, it would have the opportunity to significantly expand the supply of new products in high demand within the fashion industry, thus reviving the corresponding market during times of crisis. If indigo-dyed yarn is well-fixed and, in particular, free from dust, it holds particular significance for the production of a wide variety of potentially new, smooth, and processed fabrics and knitwear, even without mercerization. Furthermore, it could provide, in addition to conventional velvet, other sportswear and knitted jeans, which are in demand because they are far more convenient, easier to wear, and more comfortable than traditional types.

[0015] Currently, almost all machines available worldwide for dyeing skeins include "cabinet" machines, so named because of their vertical parallelepiped form. In these machines, the skeins, suspended on a series of rods with adjacent stops at one or two horizontal levels, are completely immersed in a dye bath and maintained in a bidirectional circulation (down / up and up / down) by means of a pump. These machines operate at full volume, with an average ratio of yarn weight to dye bath volume of approximately 1:13. These machines are absolutely unsuitable for dyeing indigo because their complex structure and extensive manual operation result in very high costs, and, most importantly, suboptimal quality.

[0016] In fact, to dye indigo using the traditional process involving continuous stages of immersion, extrusion, and oxidation, after the first dyeing operation, the cabinet must be emptied, the dye bath recovered, the skein removed, spun, and the dye oxidized in the air. The skein must then be reintroduced into the cabinet to repeat all the stages in further processing until the desired color is achieved. This clearly demonstrates that, in current cabinet dyeing machines, it is practically impossible to dye skeins with indigo unless a single cycle is performed to obtain a very light color; it requires numerous manual operations and the quality results are not excellent.

[0017] Therefore, although it may seem absurd, it must be admitted that, for indigo, the old manual system would have been simpler and less complex than the modern system of dyeing in cabinet machines, where the yarn was completely submerged in the tank, and all operations were obviously automated. However, this is a system that no one would think of creating today.

[0018] Although not specifically designed for dyeing with indigo, around 1890 / 1895, two skein dyeing machines were developed to modernize the older pot-type system. These machines involved a stationary dye bath and manual movement and translation of a rod attached to the skein. While the dye bath remained stationary, both machines allowed the skein to be placed on a rod arranged in a spoke-like configuration on a rotating skein support. One of these machines was manufactured in the late 19th century by the German textile engineering company Zittaer. The other machine was described on page 691 of the October 1987 issue of the Italian monthly magazine "LANIERA".

[0019] Document DE 855684C describes a third type of skein dyeing machine that is similar in design to the two machines mentioned above. However, in this dyeing machine, the skein support is divided into two parts. Besides being completely unsuitable for dyeing indigo, like the two machines mentioned above, the dyeing machine described in document DE 855684C has many design and functional problems, namely:

[0020] - The dyeing machine has an unreasonable system for loading / unloading skeins, which is done from above while the skeins are horizontal. This means that two long poles must be held at the same time, and therefore two operators are required, one on each side of the dyeing machine. The operators must be able to move on the lateral platform.

[0021] The levers are designed to load 16 strands of yarn and are approximately 2m long (in the dyeing cabinet, the largest lever is 1m long and each lever supports 8×500g strands of yarn), making them difficult to manipulate. These levers are heavy and require two operators to move.

[0022] -Due to the significant difference in circumferential speed between the inner and outer strands, the larger thickness determined by the seven rows of strands contained in the two rotating parts of the dyeing machine results in a significant difference in the percentage of residual moisture between the strands during the rotation phase, which has a negative impact on the dyeing quality.

[0023] - The yarn-bearing rod, which is usually made of a tube with a small cross-section and is 2m long and holds an 8kg dry yarn that becomes very heavy when wet, will almost certainly bend rather than remain straight during rotation.

[0024] - Allowing downtime for dripping at the end of dyeing is a serious mistake because there is always a residual moisture difference between the high and low parts of the skein, even after rotation.

[0025] - The two thicker sections of the unidirectional rotating skein have a greater impact on the stationary dye bath and hinder the necessary regular exchange between the bath and the fiber, which means that uniform dyeing cannot be guaranteed.

[0026] - Given that the dye bath actually occupies half the volume of the dyeing machine's housing, the ratio between the volume of the dye bath and the weight of the yarn is very high (probably around 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 large volume, it may be uneconomical to use a cooling system that keeps the dye bath at 15°C—the temperature at which indigo dye has the greatest affinity—or to use an ultrasonic generator to further increase the color yield.

[0028] Even if the aforementioned problems were overcome from an operational perspective, the dyeing machine described in document DE 855684C still suffers from the same insurmountable problems as the other two dyeing machines mentioned above, rendering it completely unsuitable for dyeing indigo. In fact, during the dyeing process, some spokes with skeins (in the aforementioned two dyeing machines) and one portion of the two skein carrier sections (in the dyeing machine described in document DE 855684C) remain in alternating contact with air, and are therefore subjected to harmful oxidation of the bath used to dye the corresponding skeins.

[0029] Other dyeing machines are described in documents WO 96 / 17990A1 and JP S62 6966A. However, these dyeing machines are completely unsuitable for dyeing skeins or garments with indigo dye. In fact, during the dyeing process, in these machines, most of the textile material to be dyed remains in alternating contact with air and is therefore subjected to harmful oxidation in the corresponding immersion bath. It should be noted that the dyeing machine described in document WO 96 / 17990A1 is unsuitable for industrial production due to its design and operating characteristics, as well as the specific system for positioning the skeins. Furthermore, the dyeing machine described in document JPS62 6966A lacks a support device for the skeins extending between the two arms or for suspending the skeins on a standard rod. Without these supports, the yarn of the skeins placed in the freely moving and rotating basket unit will become tangled and knotted, making subsequent untangling impossible and thus rendering the yarn itself unusable. In fact, the dyeing machine described in document JP S62 6966A appears to be a conventional rotary dyeing machine for garments, which uses the same principle that has been widely used in industrial and household washing machines for over 50 years. Summary of the Invention

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

[0031] In detail, the object of the present invention is to provide a machine for dyeing skeins and / or garments with indigo, which allows the entire dyeing cycle to be performed sequentially directly inside the machine and in an inert environment, to provide a range of quality advantages not only in terms of economy but also in terms of fastness, dye fixation and color brightness.

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

[0033] Another object of the present invention is to provide a machine for dyeing skeins and / or garments with indigo, which can operate with the minimum possible amount of dye bath, thereby significantly reducing the consumption of energy, water and chemical products (caustic soda and sodium sulfite) and thus reducing production costs.

[0034] Another object of the present invention is to provide a machine for dyeing skeins and / or garments, which can operate with a very low ratio between the weight of the yarn and the volume of the dye bath in a closed bath, with or without internal recirculation, and with or without an upper sprayer, and with a material carrier frame having one or two stages rotating slowly and alternately in two directions.

[0035] Another object of the present invention is to provide a machine for dyeing skeins and / or garments with indigo, which can use a high concentration of 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 skeins and / or garments with indigo, which can recover used dye baths containing indigo so that these dye baths can be reused after titration and replenishment of various components.

[0037] Another object of the present invention is to provide a machine for dyeing skeins and / or garments with indigo, the machine using the smallest possible volume of dye bath so that a system for cooling the dye bath itself to about 15°C can be used economically to take advantage of maximum affinity with the fibers, and an ultrasonic generator can be used to further increase the color yield.

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

[0039] Another very important object of the present invention is to provide a machine for dyeing skeins with indigo or other dyes, which uses the same skein support rod as the dyeing cabinets according to the prior art and has the same vertical loading system, thereby producing advantageous operational interchangeability with these dyeing cabinets.

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

[0041] The dyeing machine according to the invention extends horizontally and is designed to dye skeins and / or garments with a partially filled or reduced-volume dye bath under nitrogen or in contact with air (at atmospheric pressure or hydrostatic pressure). The machine internally includes one or more material carrier frames (for skeins on standard rods, which are common to all dyeing cabinets according to the prior art), which rotate at a variable speed and in both directions along a single axis. Therefore, the dyeing machine can perform the entire dyeing cycle internally with either indigo or other types of dyes.

[0042] The dyeing machine according to the invention does not suffer from any of the aforementioned disadvantages of known types of dyeing machines because it operates in an inert environment (preferably under nitrogen) in a reasonable, ergonomic, and environmentally sustainable manner. The fact that this dyeing machine operates under specific inert conditions (preferably under nitrogen) with a very low ratio between the weight of the yarn and the volume of the dye bath, approximately 1:4, allows for dyeing not only using conventional methods within the machine but also with innovative processes—single-stage and / or repeatable processes without intermediate oxidation, and separate, special operating cycles using high-concentration dye baths at low and / or high temperatures—that are not possible in conventional dyeing machines. All of this is done very quickly and in an environmentally sustainable manner.

[0043] The dyeing machine according to the invention also has the practical advantage of using the same yarn carrier rod as that commonly used in all cabinet dyeing machines according to the prior art. Therefore, the dyeing machine according to the invention can operate in perfect coordination with all cabinet dyeing machines according to the prior art. Attached Figure Description

[0044] The features and advantages of the machine for dyeing skeins and / or garments according to the invention will become more apparent from the following description, provided by way of non-limiting example with reference to the illustrative drawings, in which:

[0045] Figure 1 This is a schematic diagram of a vertical cross-section of a first embodiment of a machine for dyeing skeins and / or garments according to the present invention, which is specifically designed to dye with indigo in an inert environment.

[0046] Figure 2 yes Figure 1 A schematic diagram of the vertical longitudinal section of the dyeing equipment in the machine, within which a single rotating support frame is adapted for, for example, to accommodate the yarn carrier rod for rotation;

[0047] Figure 3 yes Figure 1 A schematic diagram of the vertical longitudinal section of the dyeing equipment in the machine, within which two rotating support frames are adapted for, for example, to accommodate the yarn carrier rod;

[0048] Figure 4A and Figure 4B This is a schematic diagram of a vertical cross-section of two possible variations of a machine according to the invention for dyeing skeins and / or garments, wherein the support frame is designed to accommodate two different types of support devices for garments; and

[0049] Figure 5 This is a schematic diagram of a vertical cross-section of a second embodiment of a machine for dyeing skeins and / or garments according to the invention, which is specifically designed to dye in the air with a dye different from indigo. Detailed Implementation

[0050] It should be noted that the following description and figures do not cover the many components, accessories, and instruments commonly found in all dyeing machines, as these are well-known to those skilled in the art. Examples of such components, accessories, and instruments include, for instance, dye bath level regulators, heat control units, preparation containers, units for recovering dye baths and supplying auxiliary products, automatic metering systems, command and control instruments, etc. It should also be noted that the figures illustrate hydraulic circuits equipped with corresponding pumps and valves; since these circuits are well-known to those skilled in the art, they will not be described in detail below.

[0051] The accompanying drawings illustrate two possible embodiments of a machine according to the invention for dyeing yarns and / or garments. The dyeing machine is generally indicated by reference numeral 10, and the dyeing machine is designed to dye yarns and / or garments with indigo and other vat dyes in an inert environment, preferably under nitrogen, and to dye yarns and / or garments with other classes of dyes in air.

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

[0053] - A housing 18, which encloses at least one dye compartment 20; and

[0054] - At least one airtight opening 22 is provided on the housing 18 and allows access to the dye compartment 20.

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

[0056] The dyeing machine 10 also includes at least one tank 24, 26 ( Figure 1 ) or 44, 46 ( Figure 5 The tanks include at least one dye bath B and at least one hydraulic circuit 28 hydraulically connected to each tank 24, 26 or 44, 46 and the dyeing apparatus 12 to supply dye bath B from each tank 24, 26 or 44, 46 to the dye compartment (20), or to supply dye bath B from the dye compartment (20) to each tank 24, 26 or 44, 46. The dyeing machine 10 also includes a plurality of support devices 30, 32, 34 for yarn skein and / or garment making, which are mounted on a support frame 14 and accessible via opening 22.

[0057] Both the housing 18 and the support frame 14 preferably have a circular form in their vertical cross-section—that is, a section obtained along a plane orthogonal to the central axis of rotation A of the support frame 14—such that the housing 18 has a cylindrical front wall, and the dye compartment 20 thus has a cylindrical form. Each opening 22 is provided on the cylindrical front wall of the housing 18, and the support devices 30, 32, 34 are arranged on the support frame 14 according to a circumferential configuration relative to the central axis of rotation A, and these devices are positioned near the inner surface of the cylindrical front wall of the housing 18, for example, in… Figure 1 , Figure 4A , Figure 4B and Figure 5 As shown in the image.

[0058] Each support frame 14 is defined by a pair of preferably circular lateral walls 36, 38, which are generally flat, opposite each other, and orthogonal to the central axis of rotation A. For example, Figure 2 A dyeing apparatus 12 is shown, comprising a single support frame 14 (single-stage configuration). On the other hand, Figure 3A dyeing apparatus 12 is shown with two different support frames 14, which are adjacent to each other in the direction of the central axis of rotation A (having a bi-level configuration). However, it is not excluded that the dyeing apparatus 12 may be provided with three or more different support frames 14 that are always arranged adjacent to each other in the direction of the central axis of rotation A.

[0059] Each opening 22 has a width measured along the central axis of rotation A, which is equal to the distance L between the two side walls 36, 38 of each support frame 14. In other words, each opening 22 is “full front” to facilitate the loading of skeins and garments into the dyeing equipment 12 and the unloading of skeins and garments from the dyeing equipment 12.

[0060] According to the present invention, in Figure 1 , Figure 2 , Figure 3 and Figure 5 In the embodiment described, the dyeing equipment 10 is designed to dye skeins. Therefore, each support device in the support device 30 is composed of a bracket that supports a plurality of skein-carrying rods 40 for dyeing the skeins. Figure 4A and Figure 4B In the variant, the dyeing machine 10 is designed to dye garments. Therefore, each of the support devices 32, 34 is composed of a perforated compartment or container having at least one opening 42. Each perforated compartment or container 32, 34 is designed to contain the garment and to dye it by means of a dye bath B passing through the opening in the perforated compartment or container 32, 34.

[0061] For example only, Figure 1 , Figure 2 , Figure 3 and Figure 5 In an embodiment of the dyeing machine 10 designed to dye skeins, each support frame 14 may have one or two levels. Therefore, each support frame 14 is preferably designed to include six supports 30, which, if viewed in a vertical cross-section, are arranged in a "hexagonal" configuration in the circumferential direction (e.g., Figure 1 and Figure 5 (as shown in the diagram), and each bracket 30 supports three or four rows of twisted yarn carrier rods 40.

[0062] According to the invention, the hydraulic circuit 28 includes one or more nitrogen and air supply circuits 50 hydraulically connected to each tank 24, 26 and the dye compartment 20 having a cylindrical shape, enabling the supply of nitrogen (N) to each tank 24, 26 and the dye compartment 20. Unlike the aforementioned dyeing machines according to the prior art, this technology allows for the dyeing of skeins and / or garments inside the dye compartment 20 with indigo and other vat dyes in an inert environment.

[0063] Two different implementations of the dyeing machine 10—in Figure 1 An implementation method is shown in the figure and in Figure 5 Another implementation is shown – the difference lies in the dyeing method and the type of dye bath B used. Figure 1 The embodiment of the dyeing machine 10 is designed to perform dyeing with indigo and other vat dyes in an inert environment and under nitrogen. Therefore, the dyeing machine 10 includes a first airtight sealed container 24 and a second airtight sealed container 26. The first airtight sealed container 24 contains an indigo-based dye bath B and a necessary amount of nitrogen N. The second airtight sealed container 26 is hydraulically connected to the first airtight sealed container 24 and serves as an auxiliary container 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 container 24 and the second airtight sealed container 26. Furthermore, in this embodiment of the dyeing machine 10, the dye compartment 20, having a cylindrical shape, may have at least one chamber 54 disposed therein, which serves as a reduction plenum chamber for the volume of nitrogen N contained in the cylindrical dye compartment 20.

[0064] on the other hand, Figure 5 The embodiment of the dyeing machine 10 is designed to perform dyeing in air with a dye different from indigo. Therefore, the dyeing machine 10 includes a first tank 44 and a second tank 46. The first tank 44 operates in air and contains a bath B of a dye different from indigo. The second tank 46 operates in air and is hydraulically connected to the first tank 44 operating in air as an auxiliary tank for the bath B of the dye different from indigo. Therefore, in this embodiment of the dyeing machine 10, no nitrogen and air supply circuit 50 is used.

[0065] Independent of this embodiment, the dyeing machine 10 may include at least one recirculation loop 48 for a dye bath B contained in a dye compartment 20 having a cylindrical shape. The dyeing machine 10 may also include one or more cascaded sprayer devices 52 hydraulically connected to the dyeing equipment 12 via a hydraulic loop 28, and these cascaded sprayer devices 52 are designed to spray the dye bath B directly into the dye compartment 20 having a cylindrical shape. The dyeing equipment 12 and / or at least one of the tanks 24, 26 may also be provided with means 56 for thermal conditioning of the dye bath B. These thermal conditioning means 56 may consist of one or more heating and / or cooling coils for the dye bath B. The dyeing equipment 12 may ultimately be provided with one or more ultrasonic generators 60 to further increase the color yield.

[0066] Therefore, the dyeing machine 10 is designed to immerse the skein or garment in a dye bath B, which occupies the lower portion of the dye chamber 20. In the absence of the dye bath B, the dyeing machine 10 can also be rotated directly, and with nitrogen (N) being expelled and air being drawn in, the dyeing machine 10 can oxidize the skein or garment by means of the rotation of the support frame 14 around its own central axis of rotation A. Due to the specific design of the dyeing machine 10, compared to the 1:13 ratio of the weight of the skein to the volume of the dye bath B in prior art dyeing cabinets, the dyeing machine 10 can actually dye at a very low ratio, approximately 1:4, of the weight of the skein to the volume of the dye bath B, and the dyeing machine 10 can directly rotate and oxidize the dyed skein and / or garment within its own interior.

[0067] The dyeing machine 10 can also use skein support rods 40 with the same dimensions as conventional cabinet dyeing machines and / or skein support rods 40 from conventional cabinet dyeing machines to perform dyeing in an inert environment (this is a particularly advantageous eco-technique described in the same applicant's documents EP 1771617 B1 and EP 1971713 B1 and document WO 2017 / 208134 A1). This interchangeability of the skein support rods 40 is very important and extremely convenient because, in order to significantly improve productivity, this interchangeability allows the dyeing machine 10 to be used only for the actual dyeing stage of the operating cycle, while, on the other hand, the remaining initial operations (absorption, soaking, etc.) and final operations (washing, soaping, softening, etc.) can still be performed in a conventional cabinet dyeing machine.

[0068] A particularly preferred structural form of the dyeing machine 10 and its rotating support frame 14—i.e., equipped with six independent support devices 30 with a relatively narrow thickness and three or four rows of yarn-bearing rods 40—is designed as follows:

[0069] - It can be operated sequentially, wherein one of the six rotating support devices 30 filled with yarn carrier rod 40 is completely immersed in the dye bath B of various chemical products and water in the dyeing machine 10 in the smallest possible volume (which also has the advantage of greatly reducing energy consumption).

[0070] - Operation is carried out in an inert environment under nitrogen (N) so that the dye bath B present in the (unsubmerged) skeins contained in the other five rotating support devices 30 will not be oxidized, but will continue to diffuse and fix the dye bath B in the fiber.

[0071] - Operated by slowly, variably and in both directions by the support frame 14 to ensure optimal exchange between the dye bath and the fiber;

[0072] -The volume of nitrogen N in the dye compartment 20 is reduced to only the outer coronal portion of the dye compartment 20 due to the reduced volume air supply chamber 54, thereby reducing the consumption of nitrogen N by 25%, and also has the advantage of shortening the inertization time.

[0073] - It can be dyed flexibly as needed and with variable capabilities, that is, it can be dyed with skeins in six (that is, all), four, three or only two support devices that are equally well positioned in the support device 30.

[0074] - The side opening 22 makes loading / unloading the yarn carrier rod 40 easy and ergonomic, without requiring a platform and / or other lifting equipment for a single operator;

[0075] - After final dehydration, a substantially uniform residual moisture is ensured between the strands on the outside and inside of each support device 30 suspended in the support frame 14.

[0076] In addition to the specific characteristics mentioned above, the fact that the operation is carried out in an inert environment, preferably under nitrogen, can be modernized using a known operating cycle for indigo dyeing. This known operating cycle essentially consists of three operating stages repeated several times (impregnating the skein with a colorless compound, eliminating excess dye bath contained in the skein, and oxidizing the dyed yarn), and adds a fourth operating stage, namely, a stage for diffusion / fixation of the colorless compound in an inert environment. Furthermore, by means of operating under nitrogen, i.e., in an inert environment, the dye bath B, which impregnates the skein held by the support device 30 and circulates from the dye bath B, not only does not oxidize, but also continues its diffusion and fixation within the fiber because the dye bath B remains in a colorless compound state.

[0077] Operating under nitrogen not only significantly reduces processing time but also enables innovative single-stage dyeing cycles at high dye concentrations and temperatures, reducing the consumption of caustic soda and sodium sulfite by 50% to 80%. Under nitrogen, the chemical reduction of indigo is complete and perfect, and the colorless compound is broken down into nanoscale particles. Compared to conventional systems, this property enhances indigo dyeing power, improves indigo penetration, strengthens indigo fixation on fibers, significantly reduces washing water consumption, and delivers excellent results in fastness, strength, and brightness—essential properties for yarns used in shirt production and knitwear.

[0078] Another technical improvement is provided by the very small volume of the dye bath B, which allows for the economical application of thermal conditioning devices 56. Specifically, these thermal conditioning devices 56 can be cooling devices, for example, capable of cooling the dye bath B to approximately 15°C. At this temperature, indigo dye has maximum affinity for cellulose fibers, resulting in better color yield, which can be further enhanced by applying one or more ultrasonic generators 60.

[0079] The dyeing machine 10 according to the invention enables an innovative dyeing method comprising a single-stage operation cycle that is repeatable and fully automated. However, this dyeing method should be considered indicative rather than mandatory, as it can be adapted to various specific production requirements and the composition of color mixing rooms and / or other specific equipment.

[0080] After preparing the full amount of dye bath B required for dyeing a single batch or multiple batches constituting the integral yarn in the first preparation tank 24, the specified amount of dye bath B required for each batch is transferred to the second auxiliary tank 26. Then the following steps are performed:

[0081] a) In the case of a single operator on the ground, the yarn carrier rod 40 with vertically placed dry yarn (which can be pre-treated directly or in a dyeing cabinet according to the prior art) is loaded into the support device 30 located in the dyeing compartment 20 through the convenient side opening 22.

[0082] b) Inertize the dye compartment 20 (and thus the yarn) and the second auxiliary tank 26, wherein the necessary amount of dye bath B can be pre-delivered to the second auxiliary tank 26, thereby keeping the dye bath B in internal recirculation and under nitrogen N.

[0083] c) When the preset residual oxygen value is reached in the dye compartment 20, the internal recirculation in the second auxiliary tank 26 is blocked and the dye bath B is started to be transferred to the lower part of the dye compartment 20, and the support frame 14 is slowly and alternately rotated in two directions.

[0084] d) Dye the yarn under necessary conditions and within a predetermined time (with or without internal recirculation of dye bath B, and with or without activation of the upper cascade sprayer device 52), and also rotate the support frame 14 slowly and alternately in both directions.

[0085] e) When the processing time has elapsed, stop the rotation of the support frame 14 and transfer the dye bath B to the second auxiliary tank 26;

[0086] f) Start rotating the support frame 14 at a preset speed for a preset time period of time to discharge the gap-filling dye bath from the yarn and to recycle the gap-filling dye bath itself into the second auxiliary tank 26.

[0087] g) Optionally, the skein is held under nitrogen (N) for a predetermined period of time, and the support frame 14 is slowly and alternately rotated in two directions to allow the dye to diffuse / fix in the fiber;

[0088] h) Optionally, repeat operations c), d), e), f), and g);

[0089] i) Rotate the yarn for a predetermined time period to recover the extracted dye bath B into the second auxiliary tank 26;

[0090] j) Isolate the dye compartment 20 from the hydraulic circuit 28 to supply / regulate nitrogen (N);

[0091] k) Make the dye compartment 20 non-inert;

[0092] l) Allow air to approach the interior of the dye compartment 20 and rotate the support frame 14 slowly and alternately in both directions for a predetermined time period to achieve oxidation of the dye;

[0093] m) Perform any washing operation and / or final treatment on the skein with or without intermediate rotation (the washing operation and / or final treatment may also be performed in a dyeing cabinet according to the prior art to improve the productivity of the dyeing machine 10).

[0094] n) Optionally, perform the final rotation operation (if point m was performed);

[0095] o) Unload the strands from the support device 30 for final drying.

[0096] For ecological and economic purposes, it should be noted that used dye baths obtained from dyeing each batch can be recycled into suitable containers (not shown) and reused after titration and replenishment of various components. It is understood that, with appropriate adjustments and simplifications, the operating cycle can also advantageously utilize other classes of dyes besides indigo. It should also be noted that, in addition to the characteristics and advantages associated with dyeing with only indigo, most of the specific characteristics of this novel machine and the aforementioned technical, economic, and ecological advantages are also applicable to dyeing many fibers with other classes of dyes.

[0097] In fact, the dyeing machine 10 according to the invention revolutionizes existing systems for dyeing skeins in dyeing cabinets. Unlike these dyeing cabinets, the dyeing machine 10 allows the entire operating cycle to be performed within the machine itself without moving materials, significantly reducing the ratio between the weight of the skein and the volume of the dye bath, and reducing energy consumption, labor, operating time, chemical products, and especially water. All of this is done in a reasonable, simple, convenient, and especially economical and environmentally sustainable manner. Compared to dyeing cabinets according to the prior art, the dyeing machine 10 according to the invention is structurally simplified, and despite being more complete, convenient, and reasonable, its economic cost is significantly reduced.

[0098] The dyeing machine 10 according to the invention is further characterized by its particular operational versatility and flexibility, as it can also dye and treat garments made of knitted or woven fabrics while the support frame 14 is rotating, and possesses all the aforementioned advantages. The demand for these processing operations is increasing because they can be performed in a short period on untreated garments already prepared for stock, allowing for rapid delivery and thus keeping pace with increasingly rapid fashion changes.

[0099] It should be noted that, since the dyeing machine 10 according to the invention is essentially constructed of a device with a cylindrical form, while the dyeing cabinet according to the prior art has a parallelepiped form, the dyeing machine 10 is advantageous and has a much lower economic cost by referring to the structure of another scheme operating under hydrostatic pressure, which is a necessary condition for dyeing skeins and / or garments made of synthetic fibers, requiring the dye bath to have a 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 with a parallelepiped form, and therefore can reach the aforementioned temperatures (120°C / 130°C), and the performance level is far higher than the maximum value of 108°C / 110°C that can be achieved in a dyeing cabinet typically pressurized to 0.4 bar.

[0100] Therefore, it has been shown that the machine for dyeing skeins and / or garments according to the invention achieves the aforementioned objectives and, in particular, provides the following advantages:

[0101] - A single machine for dyeing garments and / or standard bar yarns with indigo under nitrogen atmosphere;

[0102] - The ratio between the volume of the dye bath and the weight of the yarn is 2 / 3 lower than that of the dye bath to yarn weight ratio in dyeing cabinets according to the prior art.

[0103] - To recycle and reuse dye baths containing indigo;

[0104] -Executes the complete staining operation cycle directly internally;

[0105] - Ecological dyeing cycle using indigo and vat dyes under nitrogen atmosphere;

[0106] - To better diffuse and fix the dye onto the fiber;

[0107] - The dye bath containing indigo can be cooled and ultrasonic waves can be activated to increase the already high color yield.

[0108] - Significantly reduces the consumption of caustic soda and sodium sulfite in the case of indigo or other vat dyes;

[0109] - Reduce energy consumption;

[0110] - Reduce water consumption;

[0111] - Significantly reduces sulfites and sulfates in wastewater;

[0112] -Reduce staining time;

[0113] - Reduce production costs;

[0114] - A single-stage cycle can be performed using a dye bath with a high concentration of indigo and a high temperature;

[0115] -Maximize operational flexibility;

[0116] - It can be dyed with other types of dyes (in the air) that are different from indigo;

[0117] - It can be easily stained with variable capabilities;

[0118] - Pre-treatment and post-treatment stages can be carried out in a dyeing cabinet based on existing technology;

[0119] - It can dye garments made of knitted or woven fabrics;

[0120] - It can be operated under static pressure using a bath at a temperature above 100°C.

[0121] The machine designed in this way for dyeing skeins and / or garments can be modified and varied in many ways, all of which are within the same inventive concept; moreover, all details can be replaced with technically equivalent components. In fact, any material, form, and size can be used according to technical requirements.

[0122] Therefore, the scope of protection of this invention is defined by the appended claims.

Claims

1. A dyeing machine (10) for dyeing skeins with a dye different from indigo, said dyeing machine (10) comprising: - At least one dyeing device (12), said dyeing device (12) being provided with: - A housing (18) that encloses at least one dye compartment (20); as well as - At least one hermetically sealed opening (22), said opening (22) being provided on the housing (18) and allowing access to the dye compartment (20); - At least one support frame (14) is mounted to rotate within the dye compartment (20), and the support frame (14) is designed to rotate about a central axis of rotation (A) by means of at least one rotating pin (16), the central axis of rotation (A) being horizontal and passing through the rotating pin (16); - At least one tank (44, 46) containing at least one dye bath (B); - At least one hydraulic circuit (28) hydraulically connected to at least one of the tanks (44, 46) and the dyeing equipment (12) to supply at least one of the dye baths (B) from at least one of the tanks (44, 46) to the dye compartment (20), or to supply at least one of the dye baths (B) from the dye compartment (20) to at least one of the tanks (44, 46); as well as - A plurality of support devices (30) for the skein, the support devices (30) being mounted on the support frame (14) and accessible via the opening (22), Both the housing (18) and the support frame (14) are circular in vertical cross-section, such that the housing (18) has a cylindrical front wall and the dye compartment (20) has a cylindrical shape. The vertical cross-section is a cross-section obtained along a plane orthogonal to the central axis of rotation (A). The support device (30) is arranged on the support frame (14) in a circumferential configuration relative to the central axis of rotation (A). The support device (30) is placed near the inner surface of the cylindrical front wall. Each support frame (14) is bounded by a pair of circular side walls (36, 38), which are flat, opposite to each other, and orthogonal to the central axis of rotation (A). The support device (30) Each support device is composed of a bracket that supports a plurality of yarn carrier rods (40) for dyeing the yarn. The dyeing machine (10) is characterized in that at least one of the airtight openings (22) is provided on the front wall of the cylindrical section and has a width measured along the central axis of rotation (A), the width being equal to the distance between the two side walls (36, 38) of each support frame (14). Each yarn carrier rod (40) is a standard rod having the same dimensions as the rods of a conventional cabinet dyeing machine. Each yarn carrier rod (40) is interchangeable with the rods of the conventional cabinet dyeing machine. The dyeing equipment (12) and / or at least one of the tanks (44, 46) are provided with a device (56) for heat conditioning the dye bath (B).

2. The dyeing machine (10) according to claim 1, characterized in that, The dyeing machine (10) includes: - A first tank (44), which operates in air, containing a dye bath (B) different from indigo; and - Second tank (46), which operates in air and is hydraulically connected to the first tank (44) which operates in air.

3. The dyeing machine (10) according to claim 1 or 2, characterized in that, The dyeing machine (10) includes at least one recirculation loop (48) for housing the dye bath (B) in the dye compartment (20) having a cylindrical shape.

4. The dyeing machine (10) according to any one of claims 1 to 3, characterized in that, The dyeing machine (10) includes one or more cascaded sprayer units (52) hydraulically connected to the dyeing equipment (12) via the hydraulic circuit (28), and the cascaded sprayer units (52) are designed to spray the dye bath (B) directly into the dye compartment (20) having a cylindrical shape.

5. The dyeing machine (10) according to any one of claims 1 to 4, characterized in that, The dyeing apparatus (12) is equipped with one or more ultrasonic generators (60) to further improve color development.

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