Fabrics dyeing system

Abstract

System for open-width dyeing of fabrics comprising two squeezing rollers defining a pressure nip, a dyeing basin, unwinding means for a fabric, an apparatus for preparing dye baths, a plurality of containers downstream of said apparatus, loading and unloading ducts, and electro-actuated devices for closing and opening said ducts. The system comprises a programmable control unit. Each container can receive a respective bath and feed it to the dyeing basin independently of the other containers according to a sequence programmed and controlled by the programmable control unit such that, sequentially, while the dye bath present in one of the containers is discharged and conveyed to the dyeing basin, the electro-actuated devices for closing / opening the discharge ducts of the other containers are in the non-allowed discharge position. Said programmed sequence is continuous.

Description

[0001] TITLE

[0002] FABRICS DYEING SYSTEM

[0003] DESCRIPTION

[0004] The present invention concerns a system for open-width dyeing of fabrics.

[0005] More specifically, a system for dyeing fabrics in accordance with the present invention integrates a controlled supply of the dye bath with automatic color change modes.

[0006] Systems for open-width dyeing of fabrics are known, making use of squeezing rollers which are mutually arranged so as to define a pressure nip. At the heads of the two squeezing rollers, suitably shaped surfaces are arranged to delimit, in cooperation with the counter-facing surfaces of the same rollers, a volume suitable for containing a dye bath above the pressure nip. The fabric, which unwinds from a reel arranged upstream, passes through the dye bath, is impregnated with the color related to the formulation of the dye bath, and subsequently passes through the pressure nip undergoing a squeezing process aimed at removing the excess liquid from the fabric by compression. The fabric coming out of the squeezing rollers is then conveyed to other processes, such as steaming, for fixing the color. A problem that occurs especially when the fabric must be dyed using different baths sequentially (for example to create a sample with dyes of different color tones on the same fabric) is related to the need to stop the process at each color change to discharge the residual bath each time and to wash the bath preparation systems to avoid unwanted color contamination. Further problems are related to the quantities of unused bath discharged at each color change, quantities that are excessive compared to the current needs of environmental protection and reduction of production costs.

[0007] AU2021105387A4 discloses a system for open-width dyeing of fabrics comprising a dyeing unit and a fabric unwinding unit configured to allow the unwinding of the fabrics with passage of the fabrics through the dyeing unit.

[0008] US4193762 discloses a system for distributing a foam, containing a finishing agent, on a textile material passing through two pressure rollers.

[0009] The main object of the present invention is to overcome the aforementioned drawbacks. This result has been achieved, in accordance with the present invention, by adopting the idea of realizing a dyeing system having the characteristics indicated in claim 1. Other characteristics of the present invention are the subject of the dependent claims.

[0010] Thanks to the present invention, it is possible to control the feeding of the dye bath by reducing the amount of unused bath and to provide for the color change with automatic programmable devices providing a positive contribution to the reduction of waste and production costs.

[0011] These and further advantages and characteristics of the present invention will be more and better understood by any technician of the art thanks to the following description and the attached drawings, provided by way of example but not to be considered in a limitative sense, in which

[0012] - Fig.l is a simplified block diagram that represents a possible implementation of a dyeing system in accordance with the present invention;

[0013] - Fig.2 is a simplified block diagram relating to a possible implementation of an automatic control unit for the system of Fig. l.

[0014] Reduced to its essential structure and with reference to the attached drawings, a system for dyeing fabrics in open width in accordance with the present invention comprises a dyeing basin (1) delimited on two sides by the opposing surfaces (20, 30) of two counter-rotating squeezing rollers (2, 3) which, in cooperation with each other, define a pressure nip (P). On two other sides the dyeing basin (1) is delimited by surfaces (4) arranged in correspondence with the bases of the squeezing rollers (2, 3), such that the dyeing basin (1) is above the pressure nip (P). In Fig.l only one of said surfaces (4) is visible. The squeezing rollers (2, 3) are known per se and are arranged with their respective rotation axes (A2, A3) parallel to each other. In the exemplary diagram of Fig.1 said axes (A2, A3) are horizontal. The rotation of the squeezing rollers (2, 3), shown in Fig.1 by the arrows “R2” and “R3”, is controlled by a respective drive unit (not visible in the attached drawing) according to a construction scheme known in itself. This system also comprises an unwinding group configured and controlled to allow the unwinding of a fabric (T) from a reel (BT) with the passage of the same fabric along a pre-established path that passes through the pressure nip (P). In Fig. l the references “5” and “50” denote two return rollers on which the fabric (T) is guided, arranged upstream and respectively downstream of the pressure nip (P), and the arrows “F5” and “F50” denote the direction followed by the fabric (T) upstream and downstream of the nip groove (P) after the unwinding of the fabric by means of the aforementioned unwinding group. The fabric (T) unwinding group is structured and works according to a construction scheme known in itself. The rotation speed of the rollers (2, 3) is such that, in correspondence with the pressure nip (P), their peripheral speed substantially coincides with the advancement speed (VT) of the fabric (T).

[0015] A dyeing system according to the present invention also comprises an apparatus (AB) for preparing the dye baths to be fed to the dyeing basin (1). This apparatus typically comprises a unit (6) for dosing liquid or solid dyes with a respective dissolver (60) and a unit (7) for dosing chemical products or auxiliaries in liquid form (for example: sequestrants of various metal cations, anti-foaming agents, bluing or bleaching agents, buffering products for pH control, etc.). The dye bath, formed by the combination of the liquids coming from the groups (6) and (7), is then fed to the dyeing basin (1).

[0016] Advantageously, in accordance with the present invention and with reference to the exemplifying diagram of Fig.l, two containers (8, 9) are arranged downstream of the apparatus for preparing the dye baths, each of which is hydraulically connected, on one side, with the apparatus (AB) for preparing the dye baths and, on the other side, with the basin (1) by means of respective ducts (80, 81, 90, 91; 82, 92) so that each of said containers (8, 9) can receive a respective bath and feed it to the basin (1) independently of the other container. It is understood that the number of said containers containing and feeding the dye baths may be different from that indicated above (for example, the containers containing and feeding the dye baths could be three or four or even more in number, depending on the specific plant requirements).

[0017] Therefore, more generally, in accordance with the present invention, downstream of the apparatus for preparing the dye baths, several containers are arranged, each of which is hydraulically connected, on one side, with the apparatus (AB) for preparing the dye baths and, on the other side, with the dyeing basin (1) by means of respective ducts so that each of said containers can receive a respective bath and feed it to the dyeing basin (1) independently of the other containers.

[0018] On the discharge ducts (82, 92) that connect the containers (8, 9) to the dye basin (1) there are respective solenoid valves (V8, V9) controlled, as further described below, to allow or inhibit the feeding of the respective dye baths to the dyeing basin (1).

[0019] Inside each of said containers a corresponding agitator (83, 93) can be arranged to agitate the respective dye bath.

[0020] Preferably, said containers (8, 9) are positioned at a higher height than the dyeing basin (1) to allow the respective dye baths to be discharged by gravity towards the dyeing basin (1).

[0021] Corresponding injectors (84, 94) are mounted on the terminal sections of the discharge ducts (82, 92) which inject the respective dye baths each onto a surface (20, 30) of a corresponding squeezing roller (2, 3) near the dyeing basin (1). The rotation (R2, R3) of the rollers (2, 3) therefore determines the conveyance of the dye baths to the dyeing basin (1). Upstream of each injector (84, 94) a corresponding diverting solenoid valve (85, 95) is arranged which allows the liquid passing through the aforementioned terminal sections to be diverted into corresponding collection tanks (86, 96). In practice, by means of each diverting solenoid valve (85, 95), the liquid that passes through the terminal section of the respective duct can be conveyed to the respective injector (84, 94) or diverted towards the respective collection tank (86, 96) depending on whether it is a dye bath or washing water as further described below.

[0022] The aforementioned solenoid valves (V8, V9, 85, 95) are controlled by a programmable control unit (CS) which also controls the functional units (6, 7) of the equipment (AB) for the preparation of the dye baths. As further described below, the control unit (CS) controls the solenoid valves (V8, V9, 85, 95) and the functional units (6, 7) according to the so-called “recipe”, i.e. the formulation, of the dye baths each time formed and used. For this purpose, the control unit (CS) has, or is connected to, a memory (CM) in which the data of the dyeing process to be performed are stored. A possible operating mode of a dyeing system in accordance with the present invention, referring to the example shown in Figs.1-2, is the following.

[0023] The fabric (T) unwinding from the reel (BT) must be dyed differently along its length, i.e. consecutive portions of the fabric (T), each of a pre-established length, must be dyed with different dye baths. The fabric is drawn in, by making it to pass through the nip (P) of the rollers (2, 3). Under control of the control unit (CS), a first dye bath is prepared in the pre-established formulation stored in the memory (CM). The amount of dye bath is calculated based on the weight, composition and length of the first portion of the fabric (T) to be dyed. The first dye bath is conveyed into the container (8).

[0024] The second dye bath is then prepared and conveyed into the second container (9). The amount of the second dye bath is calculated based on the weight, composition and length of the second portion of the fabric (T) to be dyed. In this way, when the dyeing of the first portion of the fabric to be dyed (T) is completed, the system will be ready to dye the second portion of the fabric. This dyebath management mode is repeated cyclically, alternating the discharge of a dyebath from one of the containers with the loading of the next dyebath into the other container, in accordance with the sequence stored in the memory of the control unit (CS).

[0025] When any of the containers (for example, the container 8) discharges its respective dye bath, the latter reaches the dyeing basin (1) crossed by the fabric (T) that, passing also through the pressure nip (P), is then squeezed by the rollers (2, 3) and is conveyed towards other devices or systems set up downstream (for example, towards a steaming station VP). In this phase, the valve (V8) is open and the valve (85) directs the dye bath towards the injector

[0026] (84), while the valve (V9) for discharging the other container (9) is closed. Once the dye bath of the container (8) has been used up, a washing cycle is started for the container itself and for the ducts connected to it, and the valve

[0027] (85) directs the washing liquid towards the collection tank (86). Washing can be carried out with any suitable liquid, for example water. At the end of this washing cycle, the valve (V8) is closed to allow a new dye bath to be loaded into the container (8) and the valve (85) is again placed in the feeding position of the respective injector (84). In the meantime, the discharge valve (V9) of the other container (9) has been opened and the respective diverting valve (95) directs the dye bath coming from the container (9) towards the respective injector (94). Once the dye bath of the container (9) has been used up, a washing cycle is started for the container as already described with reference to the container (8). This process, which is repeated cyclically according to the programmed production until the reel (BT) is exhausted, avoids stopping the fabric (T) at each color change, i.e. each time a new dye bath must be used.

[0028] Between a color change and the next, the passage of the fabric (T) can be advantageously used to remove the residual bath present on the squeezing rollers (2, 3): in practice, a portion of fabric that follows the one to be dyed absorbs the residual dye bath present on the rollers (2, 3). The portion of fabric used to clean the rollers (2, 3) will subsequently be removed, as already happens in traditional dyeing systems in which the color change determines in any case the formation of color transition zones in which the dyeing does not correspond to the production requirements. During the color change phase, the fabric advancement speed (T) can also be reduced.

[0029] In the diagram in Fig. 2, the programmable control unit (CS) is connected to a washing unit (L) that introduces water into the containers (8, 9) through respective ducts (L8, L9).

[0030] From the description provided above, it is evident that a system for open-width dyeing of fabrics in accordance with the present invention is a system comprising two counter-rotating squeezing rollers (2, 3), a dyeing basin (1) delimited on two sides by the opposing surfaces (20, 30) of said two counterrotating squeezing rollers (2, 3) that, in cooperation with each other, define a pressure nip (P) and, on two other sides, is delimited by surfaces (4) arranged in correspondence with the bases of the squeezing rollers (2, 3), such that the dyeing basin (1) is above the pressure nip (P), an unwinding unit configured to allow the unwinding of a fabric (T) with the passage of the same fabric along a pre-established path passing through the pressure nip (P), an apparatus (AB) for the preparation of the dye baths to be fed to the dyeing basin (1), several containers (8, 9) downstream of the apparatus (AB) for the preparation of the dye baths, loading and unloading ducts (80, 90, 81, 91, 82, 92), and electroactuated devices for closing and opening said ducts (80, 90, 81, 91, 82, 92), such that each of said containers (8, 9) is hydraulically connected to the unit (AB) for preparing the dye baths and to the dyeing basin (1) by means of respective loading and unloading ducts (80, 90, 81, 91, 82, 92), wherein the system comprises a programmable control unit (CS) and each of said containers (8, 9) can receive a respective bath and feed it to the dyeing basin (1) independently of the other containers according to a sequence programmed and controlled by said programmable control unit (CS); said programmable control unit (CS) is configured to interact with the said electro-actuated devices for closing and opening said discharge ducts such that, sequentially, while the dye bath present in one of said containers is discharged and conveyed to the dyeing basin (1) through a respective discharge duct, the electro-actuated devices for closing / opening the discharge ducts of the other containers are arranged in a non-allowed discharge position, so that while one of the containers discharges the respective dye bath towards the dyeing basin (1) another container can receive a different dye bath; and said programmed sequence is continuous, i.e. without stopping the fabric (T) during the programmed sequence.

[0031] From the description provided above, it is also evident that a dyeing system in accordance with the present invention can also have one or more of the following features, even combined with each other: said unit (AB) for the preparation of dyeing baths comprises a unit (6) for dosing liquid or solid dyes with a respective dissolver (60) and a unit (7) for dosing liquid chemical products or auxiliaries. said electro-actuated devices for closing / opening said ducts are electrovalves.

[0032] - the control unit (CS) is programmed to control the introduction of a washing liquid into the containers that do not discharge a dye bath towards the basin (1) and in the respective loading / unloading ducts, on a terminal section of each of the ducts (82, 92) for discharging the dyeing baths towards the basin (1) a diverter valve (95) is arranged which allows the dyeing baths to be diverted towards a terminal injector (84, 94) or towards a tank (86, 96) for collecting the washing liquids.

[0033] In practice, the execution details may however vary in an equivalent manner with regard to the individual elements described and illustrated without departing from the scope of the solution adopted and therefore remaining within the limits of the protection granted by this patent in accordance with the appended claims.

Claims

CLAIMS1) System for open-width dyeing of fabrics in accordance with the present invention is a system comprising two counter-rotating squeezing rollers (2, 3), a dyeing basin (1) delimited on two sides by the opposing surfaces (20, 30) of said two counter-rotating squeezing rollers (2, 3) that, in cooperation with each other, define a pressure nip (P) and, on two other sides, is delimited by surfaces (4) arranged in correspondence with the bases of the squeezing rollers (2, 3), such that the dyeing basin (1) is above the pressure nip (P), an unwinding unit configured to allow the unwinding of a fabric (T) with the passage of the same fabric along a pre-established path passing through the pressure nip (P), an apparatus (AB) for the preparation of the dye baths to be fed to the dyeing basin (1), several containers (8, 9) downstream of the apparatus (AB) for the preparation of the dye baths, loading and unloading ducts (80, 90, 81, 91, 82, 92), and electro-actuated devices for closing and opening said ducts (80, 90, 81, 91, 82, 92), such that each of said containers (8, 9) is hydraulically connected to the unit (AB) for preparing the dye baths and to the dyeing basin (1) by means of respective loading and unloading ducts (80, 90, 81, 91, 82, 92), system characterized by comprising a programmable control unit (CS) and each of said containers (8, 9) can receive a respective bath and feed it to the dyeing basin (1) independently of the other containers according to a sequence programmed and controlled by said programmable control unit (CS); said programmable control unit (CS) is configured to interact with the said electro-actuated devices for closing and opening said discharge ducts such that, sequentially, while the dye bath present in one of said containers is discharged and conveyed to the dyeing basin (1) through a respective discharge duct, the electro-actuated devices for closing / opening the discharge ducts of the other containers are arranged in a non-allowed discharge position, so that while one of the containers discharges the respective dye bath towards the dyeing basin (1) another container can receive a different dye bath; and said programmedsequence is continuous, i.e. without stopping the fabric (T) during the programmed sequence.2) Dyeing system according to claim 1 characterized by in that said apparatus (AB) for the preparation of dyeing baths comprises a unit (6) for dosing liquid or solid dyes with a respective dissolver (60) and a unit(7) for dosing liquid chemical products or auxiliaries.3) Dyeing system according to claim 1 characterized in that said devices for closing / opening said ducts are electro-valves.4) 4) Dyeing system according to claim 1 characterized in that the control unit (CS) is programmed to control the introduction of a washing liquid into the containers that do not discharge a dye bath towards the basin (1) and in the respective loading / unloading ducts.5) Dyeing system according to claim 1 characterized in that on a terminal section of each of the ducts (82, 92) for discharging the dyeing baths towards the basin (1) a diverter valve (95) is arranged which allows the dyeing baths to be diverted towards a terminal injector (84, 94) or towards a tank (86, 96) for collecting the washing liquids.

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