CONTINUOUS DYEING PLANT FOR WARP THREADS COMPRISING AN OXIDATION APPARATUS HAVING VARIABLE AND RECOVERABLE CAPACITY

Abstract

A continuous dyeing plant for a warp thread including a plurality of dyeing/squeezing groups arranged in line, each of which is provided with a respective impregnation or dyeing tank in which the warp thread is immersed, and an oxidation apparatus that has a plurality of upper and lower return rollers, configured to arrange the warp thread on a plurality of vertical planes parallel to each other, and a support frame having at least one upper strut and at least one lower strut, where a plurality of upper return rollers are mounted on the upper struts, such that at least one part of the lower return rollers is rotatably mounted on at least one respective support device that is movable in the vertical direction between a first operating position, in which the movable support device is placed close to the lower struts to keep the lower return rollers at a maximum predefined distance from the corresponding upper return rollers, and a second operating position, in which the movable support device is placed close to the upper struts to keep the lower return rollers at a minimum predefined distance from the corresponding upper return rollers.

Claims

1. Continuous dyeing plant with a dyeing substance for a warp thread, the dyeing plant comprising: a plurality of dyeing/squeezing groups arranged in line, each of said dyeing/squeezing groups being provided with a respective impregnation or dyeing tank into which the warp thread is immersed; an oxidation apparatus that comprises a plurality of upper and lower return rollers, which are configured to place the warp thread onto a plurality of vertical planes parallel to each other, and a support frame placed downstream of said plurality of dyeing/squeezing groups, said support frame comprising at least an upper strut and at least a lower strut forming a laterally, downwardly and upwardly open structure to allow the oxidation of the dyeing substance by means of the contact of the dyed warp thread with the maximum possible amount of air, a plurality of upper return rollers being mounted on said at least one upper strut; and an electronic control unit, wherein at least one part of the lower return rollers is rotatably mounted on at least one respective support device that is movable in a vertical direction between a first operating position, wherein said movable support device is placed at said at least one lower strut in order to keep the lower return rollers at a maximum predefined distance from the corresponding upper return rollers, and a second operating position, wherein said movable support device is placed at said at least one upper strut in order to keep the lower return rollers at a minimum predefined distance from the corresponding upper return rollers.

2. Dyeing plant according to claim 1, wherein each movable support device is vertically moved along a plurality of linear guide uprights, said linear guide uprights being integral at the bottom to a pair of lower struts, parallel to one another, and integral at the top to a pair of upper struts, parallel to one another and to said lower struts, wherein said upper struts and said lower struts, together with said linear guide uprights of each movable support device, constitute the perimeter of a parallelepiped-shaped cage that supports the upper return rollers and the lower return rollers.

3. Dyeing plant according to claim 1, wherein each movable support device is provided with upper struts separated from the corresponding upper struts of the movable support devices that are contiguous thereto.

4. Dyeing plant according to claim 3, wherein the linear guide uprights of each movable support device are made integral to the lower struts by means of reversible fixing means.

5. Dyeing plant according to claim 1, wherein each movable support device is provided with at least one movement means that is operatively associated with the support frame and with the electronic control unit of the dyeing plant.

6. Dyeing plant according to claim 1, further comprising one or more movement means operatively associated on one side, with the support frame and, on the other side, by means of corresponding movement transmission means, with a plurality of movable support devices that are separated from each other.

7. Dyeing plant according to claim 5, wherein each movement means comprises at least one of: movement means of the pneumatic type; movement means of the hydraulic type; movement means of the electric type; and movement means of the mechanical type.

8. Dyeing plant according to claim 5, wherein each movement means is of the pneumatic type and comprises a pneumatic actuator cylinder, which is integral with a fixed portion of the support frame, the stem of which is integral with a respective movable support device.

9. Dyeing plant according to claim 8, wherein each stem is integral with a respective movable support device by means of the interposition of a guide rod.

10. Dyeing plant according to claim 1, wherein each movable support device is placed downstream of a first impregnation or dyeing tank and upstream of the following impregnation or dyeing tank.

11. Dyeing plant according to claim 1, further comprising a position transducer configured to place one or more movable support devices at a predefined intermediate height between said least one lower strut and said at least one upper strut of the support frame.

12. Dyeing plant according to claim 1, wherein each movable support device is provided with at least one sensor operatively connected to the electronic control unit of the dyeing plant, said at least one sensor being configured to identify the achievement of the maximum limit of the upper and/or lower end stroke, with reference to the upper struts and to the lower struts of the support frame respectively, by each movable support device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The characteristics and advantages of an oxidation apparatus for continuous indigo dyeing plants according to the present disclosure will become clearer from the following description, given as an example and not for limiting purposes, referring to the attached schematic drawings, in which:

[0019] FIG. 1 is a side elevational view of a generic continuous indigo dyeing plant, provided with a plurality of dyeing/squeezing groups, on which it is possible to mount an oxidation apparatus having variable and recoverable capacity according to the present disclosure;

[0020] FIG. 2 is a schematic view of a part of a generic dyeing plant, provided with three dyeing/squeezing groups, between which an oxidation apparatus having fixed capacity according to the prior art is arranged;

[0021] FIG. 3 is a schematic view of a part of a generic dyeing plant, provided with three dyeing/squeezing groups, between which an oxidation apparatus having variable and recoverable capacity according to the present disclosure is arranged, shown in the position of maximum capacity;

[0022] FIG. 4 is a schematic view of a part of a generic dyeing plant, provided with three dyeing/squeezing groups, between which an oxidation apparatus having variable and recoverable capacity according to the present disclosure is arranged, shown in the position of minimum capacity;

[0023] FIG. 5 is a perspective view of a particular embodiment of the oxidation apparatus having variable and recoverable capacity according to the present disclosure, shown in the position of maximum capacity; and

[0024] FIG. 6 is a perspective view of the oxidation apparatus having variable and recoverable capacity of FIG. 5, shown in the position of minimum capacity.

DETAILED DESCRIPTION

[0025] With reference in particular to FIG. 1, a generic continuous dyeing plant for threads is shown, wholly indicated with reference numeral 10. In particular, the plant 10 is a plant configured to operate according to the open width dyeing system.

[0026] The plant 10 comprises a plurality of dyeing/squeezing groups 12 arranged in line, each of which is provided with a respective impregnation or dyeing tank 14A, 14B, 14C in which a warp thread 100, which advances from left to right with reference to the representation of the plant of FIG. 1, is immersed in a dyeing bath containing a dyeing substance. The dyeing bath can, for example, comprises an alkaline solution of indigo dye.

[0027] As shown in FIGS. 2-4, the warp thread 100 arrives in each tank 14A, 14B, 14C passing over a respective guide roller 16 and then immerses in the tank 14A, 14B, 14C itself winding onto a plurality of return rollers 18. At the exit of each tank 14A, 14B, 14C the warp thread 100 undergoes a squeezing passing between a pair of squeezing cylinders 40 that constitute the so-called squeezing padder.

[0028] The oxidation of the warp thread 100 is carried out in the area of the dyeing plant 10 arranged between the pair of squeezing cylinders 40 at the exit of a first tank 14A and the guide roller 16 associated with the next tank 14B. The oxidation of the warp thread 100 is thus carried out by a suitable oxidation apparatus 20 that comprises a plurality of return rollers 22A, 22B configured to arrange the warp thread 100, which is in continuous movement, on a plurality of vertical planes parallel to one another (see FIGS. 2-4), so as to increase the surface thereof exposed to air.

[0029] Conventional oxidation apparatuses 20, for example like the one shown in FIG. 2, comprise a support frame 24 on which the return rollers 22A, 22B are rotatably mounted. The support frame 24 is normally placed downstream of the dyeing/squeezing groups 12 and comprises a laterally, downwardly and upwardly open structure to allow the oxidation of the dyeing substance by means of the contact of the dyed warp thread 100 with the maximum possible amount of air. The support frame 24 thus comprises at least one upper strut 26 and at least one lower strut 28 on which a plurality of upper return rollers 22A and a plurality of lower return rollers 22B are respectively mounted. The distance between the upper strut 26 and the lower strut 28 and, therefore, between the upper return rollers 22A and the lower return rollers 22B is fixed. Consequently, the conventional oxidation apparatus 20 has a fixed capacity or, in other words, the amount of thread 100 exposed to air between two contiguous tanks 14A, 14B, 14C is constant.

[0030] The oxidation apparatus 20 according to the present disclosure, schematically illustrated in FIGS. 3 and 4, also comprises a support frame 24 placed downstream of the dyeing/squeezing groups 12 and comprising a laterally, downwardly and upwardly open structure to allow the oxidation of the dyeing substance by means of the contact of the dyed warp thread 100 with the maximum possible amount of air. The support frame 24 again comprises at least one upper strut 26 and at least one lower strut 28. On the upper strut 26 a plurality of upper return rollers 22A are mounted, whereas at least one part of the lower return rollers 22B is rotatably mounted on at least one respective movable support device 30A, 30B, 30C. In detail, each support device 30A, 30B, 30C is movable in the vertical direction between a first operating position (FIG. 3), in which such a movable support device 30A, 30B, 30C is arranged close to the lower strut 28 of the support frame 24 to keep the lower return rollers 22B at a maximum predefined distance from the corresponding upper return rollers 22A, and a second operating position (FIG. 4), in which such a movable support device 30A, 30B, 30C is arranged close to the upper strut 26 of the support frame 24 to keep the lower return rollers 22B at a minimum predefined distance from the corresponding upper return rollers 22A.

[0031] In other words, the oxidation apparatus 20 according to the present disclosure is provided with a plurality of movable support devices 30A, 30B, 30C that operate from movable platforms for at least one part of the lower return rollers 22B. Each movable platform 30A, 30B, 30C, suitably guided and tensioned, can rise and fall inside the support frame 24 of the oxidation apparatus 20, thus making it possible to vary the capacity of use of the oxidation apparatus 20 itself and drastically reduce, in the change of batch step of the warp thread 100 (stopping/restarting of the dyeing plant 10), the amount of thread 100 contained in the dyeing plant 10 to avoided discarding it.

[0032] With reference to the particular embodiment of FIGS. 5 and 6, each movable support device 30A, 30B, 30C of the oxidation apparatus 20 according to the present disclosure can be moved vertically along a plurality of linear guide uprights 32, integral at the bottom to a pair of lower struts 28, parallel to one another, of the support frame 24 and integral at the top to a pair of upper struts 26, parallel to one another and to the lower struts 28, of such a support frame 24. In other words, the upper struts 26 and the lower struts 28 of the support frame 24, together with the linear guide uprights 32 of each movable support device 30A, 30B, 30C, constitute the perimeter of a parallelepiped-shaped cage that supports the upper return rollers 22A and the lower return rollers 22B.

[0033] Each movable support device 30A, 30B, 30C of the oxidation apparatus 20 can also be provided with upper struts 26 separate from the corresponding upper struts 26 of the movable support devices 30A, 30B, 30C contiguous to it, so as to make the entire oxidation apparatus 20 modular. In other words, the linear guide uprights 32 of each movable support device 30A, 30B, 30C can be made integral to the lower struts 28 by means of reversible fixing means 46, like for example bolts.

[0034] Each movable support device 30A, 30B, 30C of the oxidation apparatus 20 can be provided with at least one movement means 34, operatively associated with the support frame 24 of the oxidation apparatus 20 and with the electronic control unit 50 of the dyeing plant 10. Alternatively, a single movement means 34 or a plurality of movement means 34 can be provided, operatively associated on one side with the support frame 24 of the oxidation apparatus 20 and on the other side, by means of corresponding movement transmission means (not shown but comprising for example belts, chains or transmission shafts), with a plurality of movable support devices 30A, 30B, 30C that are separate from one another.

[0035] Each movement means 34 can without distinction be of the pneumatic, hydraulic, electric or mechanical type, or it can comprise a combination of such systems. In the embodiment shown in FIGS. 5 and 6, the movement means 34 is of the pneumatic type and comprises a pneumatic actuator cylinder 36, integral to a fixed portion of the support frame 24, the stem 38 of which is integral to a respective movable support device 30A, 30B, 30C by means of the interposition of a guide rod 42.

[0036] The oxidation apparatus 20 according to the present disclosure makes it possible to vary the amount of thread 100 exposed to air for oxidation with a process that has the following steps. During the indigo dyeing process, all of the movable support devices 30A, 30B, 30C of the dyeing plant 10 are normally placed at the bottom, in other words in their first operating position of FIG. 3, on the respective support frame 24. The warp thread 100, in a per se known way, is tensioned according to requirements by weights, by one or more pneumatic pistons or other. In this first operating position of the movable support devices 30A, 30B, 30C there is the maximum amount of thread 100 exposed to air for oxidation.

[0037] By means of a position transducer 48 it is also possible to place one or more movable support devices 30A, 30B, 30C at a predefined intermediate height between the lower struts 28 and the upper struts 26 of the support frame 24. This intermediate height can be set and/or modified automatically and/or manually to increase or reduce the amount of thread 100 passed through the dyeing plant 10, adapting it to possible production requirements.

[0038] At the end of each batch of thread intended for dyeing, the warp thread 100 that feeds the dyeing plant 10 is practically all passed through, with the exception of the few metres of reserve that are necessary to tie it to that of the new batch of thread.

[0039] In this operating condition all of the traction motors of the warp thread 100 from the driving calandar up to the squeezing cylinders 40 of the first dyeing tank 14A stop, leaving in operation all of the remaining motors of the part of dyeing plant 10 placed downstream of such a first dyeing tank 14A.

[0040] The stopping of all of the traction motors of the warp thread 100 that are placed upstream of the first dyeing tank 14A, as well as of the traction motors of the warp thread 100 that belong to the first dyeing tank 14A itself, forces the dyeing plant 10 to be fed with the warp thread 100 passed through the portion of oxidation apparatus 20 placed immediately downstream of the first dyeing tank 14A. Consequently, the first movable support device 30A arranged between the first dyeing tank 14A and the second dyeing tank 14B is lifted proportionally to the decrease in the amount of thread 100 passed through the aforementioned portion of oxidation apparatus 20 placed immediately downstream of the first dyeing tank 14A.

[0041] The lifting of the first movable support device 30A continues until the respective second operating position of FIG. 4 is reached, in other words until the maximum limit of the upper end-stroke with reference to the upper struts 26 of the support frame 24 is reached. The electronic control unit 50 of the dyeing plant 10 is operatively connected to at least one sensor 52 provided on each movable support device 30A, 30B, 30C. Consequently, once it has been identified through the sensor 52 that the maximum limit of the upper end-stroke has been reached by the first movable support device 30A, the electronic control unit 50 stops the actuation motors of the squeezing cylinders 40 of the second dyeing tank 14B.

[0042] The operations described above will be repeated for the second movable support device 30B arranged between the second dyeing tank 14B and the third dyeing tank 14C as well as, in an identical and sequential manner, for all of the next dyeing tanks. The emptying of the end portion of the oxidation apparatus 20, in other words of the last movable support device, will stop all of the remaining motors of the dyeing plant 10 still operating, i.e. those of the washing tanks 44 placed downstream of all of the dyeing/squeezing groups 12.

[0043] It has thus been seen that the oxidation apparatus 20 applicable to the continuous indigo dyeing plants according to the present disclosure achieves the purposes highlighted earlier. The clear advantage of being able to recover two times, and thus of being able to use, conservatively, at least 80% of the amount of thread 100 passed through the oxidation apparatus 20, which in dyeing plants equipped with conventional oxidation apparatuses is discarded, is added to with the advantage of a substantial reduction of the time necessary for the change of batch operation.

[0044] The fact that the amount of thread 100 contained in the dyeing section is reduced to the minimum, by positioning the movable platforms that constitute the movable support devices 30A, 30B, 30C of the return rollers 22A, 22B of the oxidation apparatus 20 at the maximum upper limit, drastically reduces the time needed for passing the joining knots of the two batches of thread 100 and of the combs that adjust the width thereof, during the change of batch operations, which must be carried out at reduced speed for technical and safety reasons.

[0045] Moreover, the same advantages described above and referring to the end of dyeing operations are also obtained in the subsequent starting operations of the new batch of thread 100. These operations are carried out in the opposite direction, i.e. introducing into the dyeing plant 10, at low speed, the new batch of thread 100 with all of the movable support devices 30A, 30B, 30C passed through with the minimum amount of thread 100, in other words in the second operating position of FIG. 4. Thereafter, the total capacity of the oxidation apparatus 20 is restored by moving the movable support devices 30A, 30B, 30C downwards in sequence, starting from that of the first dyeing tank 14A up to that of the last dyeing tank, to then proceed with the dyeing operations of the thread 100 in a conventional manner. In this case, the electronic control unit of the dyeing plant 10 is configured to identify that the maximum limit of the lower end-stroke (with reference to the lower struts 28 of the support frame 24) has been reached by the various movable support devices 30A, 30B, 30C, so as to start in sequence the actuation motors of the dyeing/squeezing groups 12.

[0046] The oxidation apparatus 20 having variable and recoverable capacity according to the present disclosure can be inserted in any conventional indigo dyeing plant. In the same dyeing plant 10, a variable number of movable support devices 30A, 30B, 30C can also be provided according to requirements.

[0047] The oxidation apparatus applicable to the continuous indigo dyeing plants of the present disclosure thus conceived can in any case undergo numerous modifications and variants, all of which are covered by the same inventive concept; moreover, all of the details can be replaced by technically equivalent elements. In practice, the materials used, as well as the shapes and sizes, can be whatever according to the technical requirements.

[0048] The scope of protection of the disclosure is therefore defined by the attached claims.