PROCESS AND APPARATUS FOR THE BATCHWISE TREATMENT OF LAP-FOLDED FABRICS

Abstract: For the batchwise dyeing of lap-folded fabrics, a container (10) is provided, which is interiorly vertically subdivided into two compartments, and is provided, above the compartments (20,21), with a motor-driven winch (14), the revolution direction of which is reversible on command. The fabric (17), which can be in rope form, or in open-width form, runs on the winch, and is moved by this latter in combination with a system of ejectors (15,16), which spray the dyeing bath onto the fabric. The fabric is anchored at its two ends at two points (18,19) of the container which are substantially opposite to each other, in the container area above the compartments, and is made alternatively move, gathering from either of the compartments into the other one.

Description: The present invention relates to a machine for the batchwise treatment, in particular for the batchwise dyeing, of lap-folded fabrics. It is known that the batchwise dyeing of running lap-folded fabrics can be carried out by several types of machines, each type being endowed with specific advantages, but also showing specific limitations, which do not enable it to be advantageously used in all cases. Machines are known which process fabrics closed to a ring configuration, both in rope form and in open-width form, and are substantially provided with a revolving winch, having a polygonal or oval cylindrical shape, which, when installed above a processing vat, lays down the fabric, folded to a lap configuration, along a sloping bottom of the vat, then collecting it again from the opposite side. The machines of this type can process a plurality of fabrics in rope form, arranged side by side and separated by suitable spacers, dipped inside the same treatment vat. But these machines require rather high bath ratios, ranging from a minimum of 1:20 up to more than 1:100, and this represents a negative factor from the standpoint of process economics. Furthermore, the treatment times are high, both because of the slow circulation speed of the fabrics, which are extracted vertically from the bath, due to the pull exerted by the winch, and to the high volumes of the baths to be heated or cooled. The low efficiencies, and the considerable costs of attending personnel render these machines generally not very advantageous from the economical standpoint. These negative aspects are not present, on the contrary, in the machines of the so said "jet" type, in which the dyeing or treatment bath, forced through particular ejectors facing the fabric, is used as the means for moving the same fabric which, in this case too, is closed to a ring configuration. The fabric is made circulate through a closed container. The advancement speed of the fabric is higher that that in the previously described machines, with a consequent reduction of the duration of the processing cycles, and with a higher efficiency. Also the bath ratios are considerably lower, by being generally comprised within the range of from 1:5 to 1:7, which is also advantageous from the viewpoint of the regular moving of the fabric. It is possible to treat greater lengths and larger weights of fabric than in case of the previously described machines. In front of these appreciable advantages, the drawback exists however that these machines are only suitable to treat exclusively fabrics in rope form and, above all, the drawback is shown that the violence of the bath stream impinging against the fabric, necessary for accomplishing high-speed advancements, easily causes removals of fabric pile, due to the rubbing of the treatment liquid on the fabric being treated. The just described drawback, and the above said limitation of the machines of "jet" type are partly overcome with the dyeing machines of the so-said "overflow" type, which, even if they resemble, in their outer shape and geometric characteristics, the "jet"-type machines, are equipped with lower-capacity ejectors, which have simpler shapes, and are often as simple as funnels or chutes. In these machines, the task of fabric driving is entrusted to a combined action of a winch and of the treatment, or dyeing, bath, pumped in a direction opposite to the direction of movement of the fabric. The advantage is hence achieved of a softer processing, and hence of the safeguard of the more delicate fabrics. On the other hand, the bath ratios in these machines are not as low as those used in the "jet" machines, and are generally comprised within the range of from 1:8 to 1:12. Also the fabric advancement speed results lower, with consequent longer treatment times, and higher end costs. Besides by these machines, the dyeing of travelling fabrics is also carried out by means of machines of the so-said "jigger" type, which treat fabric in open-width form, alternatively passing it, inside a dyeing bath, from one winch to another one, with several cycles of alternative winding on the one, and on the other winch. By operating in both travelling directions, the passage of the dyeing liquid, or of the treatment liquid through the textile interlacement is favoured, thus reaching a more uniform dyeing or treatment level. But these machines can only handle open-width fabric, perfectly flattened and with a minimum tension, essential for the function of the stretchers. From FR-A-2 412 637 there is known a machine for the batchwise treatment of lap-folded fabrics having the features of the preamble of claim 1. In this machine, the fabric is caused to alternatingly pass through an impregnation tube arranged either between two winches or beneath a single winch, to impregnate the fabric with the treatment liquid. In order to obtain a good impregnation and therefore a satisfactory treatment of the fabric, the tube must be sufficiently long, so increasing the overall dimensions of the machine, or the fabric must be moved slowly through the tube, so increasing the time for having the treatment completed. The purpose of the present invention is to obviate the limitations and drawbacks of the prior art machines by proposing a machine for the batchwise treatment, in particular for the dyeing, of lap-folded fabrics, which is suitable to treat both fabrics in rope form and in open-width form, and which, with small bath ratios, makes it possible to rapidly carry out a uniform treatment for a very wide range of types, weights and compositions of fabrics, with knitted fabrics being included, safeguarding the fabrics against tensions and rubbings. This purpose is achieved by a machine having the features claimed in claim 1. The characteristics and advantages of the present invention are better understandable from the following disclosure of an example of a preferred, but not exclusive, form of practical embodiment of the invention, shown in the hereto attached drawings, wherein: Figure 1 shows a schematic transversal sectional view of a machine according to the invention, with the fabric being folded to a lap configuration, and gathered inside one of the two interior compartments which subdivide the container into two parts; Figure 2 shows once more the machine of Figure 1, with the fabric being folded to a lap configuration, and gathered in the compartment opposite to the compartment of Figure 1; Figure 3 shows a schematic view of a possible electromechanical control means for the automatic reversal of the fabric travelling direction; Figure 4 shows a schematic sectional view of an ejector for soaking the fabric in another form of practical embodiment. Referring to Figures 1 and 2, a machine for the treatment of a running lap-folded fabric according to the present invention comprises a treatment container, preferably of parallelepipedal shape, generally indicated with 10, and preferably provided with a top cover 11. Advantageously, the container 10 is positioned with its axis being vertical. The container 10 shows, in two opposite side areas, two openings, preferably closeable, such as a manhole 12 for entering the container and charging the fabric to it, and a porthole 13 for accessing the container 10 and performing the necessary operations and inspections. Inside the container 10, in the upper portion of the container, a motor-driven winch 14 is provided, which is rotatable about a stationary axis and which, together with two systems of stationary ejectors 15 and 16, positioned beneath the winch 14 symmetrically on opposite sides relatively to the vertical middle plane of the winch adjacent the path of the fabric 17, performs the task of transporting the fabric 17 to be processed. Said fabric 17 is not closed to a ring configuration, but is constrained at both of its ends to two fixed points by means of suitable fastening means 18 and 19 inside the container 10, provided on diametrically opposite sides in the upper portion of the container 10, under the winch 14, respectively in the nearby of the porthole 13 and of the manhole 12. As it can be seen in the drawing, the two systems of ejectors 15 and 16 are positioned at an intermediate level between the winch 14 and the fastening means 18 and 19, along the route along which the fabric 17 travels. Under the motor-driven winch 14 and the ejectors 15 and 16, the container 10 is advantageously subdivided into two compartments 20 and 21 by a vertical wall 22, preferably perforated, which extend down to a point slightly above the bottom of the container 10. The ejectors 15 and 16 are alternatively fed by the same dyeing or treatment liquid, according to the position of a threeway valve 23 associated with the same ejectors. The solution of the dyeing or treatment liquid sprayed by the ejectors 15 and 16 with a vertical direction component onto the fabric passing through the systems of ejectors is collected in a region 24 on the bottom of the container 10 and then, by means of a pump 25, is recycled through a pipe 26 which reaches the valve 23. With the pipe 26, a heat exchanger 27 is associated, in order to heat/cool the treatment liquid to the necessary temperature for the type of treatment to be carried out, during both the heating and cooling steps. The winch 14 can be alternatively actuated into both the directions of revolution, by being associated, e.g., with motor means (not shown) of a reversible type. The reversal of the direction of revolution of the winch 14 takes place simultaneously with the reversal of the position of the distribution valve 23, in such a way that when the winch 14 revolves in a certain directions (Figure 1 or Figure 2), the valve 23 delivers the liquid to that one of the ejectors 15 or 16, which is arranged downstream of the winch 14 in the travelling direction of the fabric 17 and directs the liquid jets to the direction concurrent with the direction of travelling of fabric 17. The treatment of the fabric by means of the disclosed machine takes place as follows. An end of the fabric 17 to be treated is introduced inside the container 10, through the manhole 12, is laid down upon the winch 14, and is inserted through the ejector 15, using the opening provided by the porthole 13. At this point, the winch 14 is started up; it makes it possible to recover the end of the fabric 17, and to fasten it at 18. Then, with the aid of the bath solution delivered by the pump 25 into the ejector 15, the fabric 17 is laid down in the form of wet laps inside the compartment 20 of the container 10, while the fabric 17 continues to be fed from the outside through the manhole 12, which remains open. After the charge is completed, the rear end of the fabric 17 is fastened at 19, after being inserted inside the ejector 16. When these operations have been finished, the machine is ready to operate. The winch 14 is now made revolve in the opposite direction, and the only ejector 16 starts operating, which contributes to move the fabric, which, while is being soaked with the treatment liquid, gathers in the form of laps inside the compartment 21, emptying the compartment 20 (Figure 2). At the end of passage of fabric 17 from compartment 20 to compartment 21, the direction of revolution of the winch 14 is reversed, and the ejector 15 starts operating, with the result that the fabric is brought back into the compartment 20, and so on, for a determined number of times, pre-established as a function of the type of treatment and/or of the type of fabric, or of other parameters. The fabric 17 is hence alternatively gathered inside the one, and inside the other, part of the container, while it is kept fixed at its ends inside the container 10, and is soaked with the treatment liquid during its passage from one part to the other part of the container 10. The reversal of the direction of revolution of the winch 14, and the switching of the valve 23 can take place also automatically, as a function of the position of the fabric, by being controlled by the same fabric at the end of the gathering inside the one, or inside the other, of the compartments 20, 21. For example, as shown in Figure 3, under the ejectors 15 and 16, a rocker arm 28 can be provided, positioned symmetrically relatively to the vertical middle plane of the winch 14 and in the proximity of the fastening means 18 and 19, at the ends of said rocker arm 28 guide rollers 29 and 30 for the fabric 17 being provided. The rocker arm 28 has integral therewith, at the fulcrum 31 thereof, a movable element 32 for actuating an electrical contact, which, according to the position of the rocker arm, closes the one, or the other one, of two stationary contacts 33, 34, of a circuit for actuation of the valve 23 and of the motor means of the winch 14 respectively to the one, or to the other direction. The displacement of the rocker arm 28 is caused by the same fabric at its stroke end, due to the tension of the fabric in that position. In Figure 4, an alternative form of ejector is shown, which can be advantageously used in the machine as disclosed, and wherein the bottom walls 35 of the collection chambers 36 for the pressurized liquid exiting the ejectors are perforated for the purpose of sprinkling the fabric 17. It is thus possible to sprinkle the fabric in a more uniform way, while the filling of the respective compartment 20 or 21 with the fabric laps is taking place. The share of sprinkled bath, relatively to that pumped to the ejectors 15 or 16 may vary within a wide range, e.g., from 20 to more than 50% of the total. From the above disclosure, one can understand that in a machine according to the invention, the bath ratios are advantageously reduced, with they being adjusted to the minimum volumes strictly necessary to fill the members of the machine, and to soak the fabric. In fact, the fabric is no longer left dipped inside a bath advancing at its same speed, but the soaked fabric is continuously soaked by the bath stream which exits the ejectors, to reach the bottom of the container. The small bath ratios allow the filling and emptying times, on bath changes, to be limited to the minimum, and it is furthermore possible to increase the bath heating or cooling rate, with the exchange surface of the heat exchanger being the same. The bath volume necessary for an optimum function is given by the sum of the volume absorbed by the fabric, plus the volume contained inside the pipes and inside the ejector-pump system, plus that necessary for reaching the level to feed the circulation pump. In total, approximately from 3 to 4 times the weight of the fabric, for an average machine charge. In practice, bath ratios lower than 1:4 can be reached, independently from the lengths and the weights of the fabrics. The continuous reversing of the direction of travelling of the fabric produced by the reversible winch 14 in combination with the alternatively operating ejectors 15 and 16, secures an optimum evenness of treatment of the same fabric, notwithstanding the changes in temperature and in characteristics of the individual baths, which may occur during the cycles. In as much as the fabric is laid down vertically relatively to the wet layer, but not "under bath", and thanks to the continuous reversing of the movement direction, the causes of formation of knots and irregular windings are removed, with the further advantage of the increase in the sliding speed of the same fabric. Another important advantage of the present invention is that sewing the fabric to close it to a ring configuration for the treatment is no longer necessary, but the fabric is left "open", anchored at its ends, and is not made circulate. In this way, the operations of machine charging and discharging are made quicker, and the problem does no longer exist, of having to find the sewing point during the sampling operations, and when the fabric is discharged from the machine. The treatment times result particularly reduced. It has been found that with a machine according to the invention, travelling speeds of the fabrics higher than 500 m/minute can be reached. In a machine according to the invention, not only is the fabric substantially vertically drawn from a side of the container, but it is also laid down in substantially vertically overlapping laps in the other side of the container, a fact this, which makes it possible the fabric to be continuously soaked by the liquid exiting the ejectors, securing an efficacious impregnation of the fabric, in particular in case wherein to the action of the ejectors, the "sprinkling" action according to the form of practical embodiment of Figure 4 is added. The particular modality of treatment according to the present invention makes it possible to treat a very wide range of fabric types, with different weights and compositions. In particular, it is possible to treat or dye fabrics in rope form, as well as fabrics in open-width form. In an analogous way, knitted fabrics can be treated. The fabric is treated delicately, without rubbings or tensions. The container could have the shape of an open vat. It could also be an autoclave for treating the fabric in a pressurized environment, e.g., under a pressure of 4 bars. The ejectors 15 and 16 could be of adjustable-capacity type. The system for running direction reversal could be also driven by means of timer means.

Claims: A machine for the batchwise treatment, in particular for the batchwise dyeing, of lap-folded fabrics, comprising a treatment container (10) having two parts (20, 21) for receiving the fabric (17), reversible transport means for transporting the fabric (17) alternatively from either part (20 or 21) of the container (10) to the other part (21 or 20) thereof, means for subjecting the fabric (17) to the action of a treatment liquid during its movement between said parts (20, 21), and means (18,19) for fastening the ends of the fabric (17) inside the container (10), wherein said reversible transport means comprise a winch (14) rotatable about a stationary axis arranged above said parts (20, 21) of the container (10), characterised in that said means for subjecting the fabric (17) to the action of a treatment liquid comprise two systems of stationary ejectors (15,16) arranged symmetrically beneath said winch (14) adjacent the path of the fabric (17) for directing jets of treatment liquid with a vertical direction component onto the fabric (17) passing through said ejector systems. A machine according to claim 1, characterised in that a distribution valve (23) is associated with said systems of ejectors (15,16), for alternatingly delivering the treatment liquid to the one and the other of the two ejector systems as a function of the direction of revolution of the winch (14), the system delivered being respectively the one arranged downstream of the winch (14) in the travelling direction of the fabric (17). A machine according to claim 1 and/or 2, characterised in that said reversible transport means (24) and/or said valve (23) are controlled by the position of a rocker arm (28) displaced by the fabric (17) at the end of the gathering inside the one, or the other one, of the two parts (20, 21) of the container (10). A machine according to claims 1 and 3, characterised in that the means (18, 19) for fastening the ends of the fabric (17) are provided on opposite sides inside the container (10) in the proximity of said rocker arm (28). A machine according to claim 1, characterised in that said ejectors (15,16) are located at an intermediate level between said winch (14) and said fastening means (18,19). A machine according to claim 4 or 5, characterised in that in the proximity of said fastening means (18, 19) the container (10) is provided with respective openings (12, 13) for intervention and inspection. A machine according to claim 1, characterised in that said container (10) is an autoclave. A machine according to claim 1, characterised in that the treatment bath ratio is lower than 1:4. A machine according to claim 1, characterised in that said systems of ejectors (15,16) comprise also sprinkling means. A machine according to claim 1, further comprising means (25,26) for recycling the treatment liquid between the bottom of said container and said systems of ejectors (15, 16).

Inventors: CHIAPPINI, LUIGI
Applicants: M C S OFFICINA MECCANICA S.P.A.
Application year: 1987
Main classification: D06B3
IPC codes: D06B3