In-line process and machine for shrinking tension-sensitive yarns

Abstract

The present invention relates to an in-line process and a machine for shrinking tension-sensitive yarns, which, in addition to comprising a step of unwinding by means of a creel (1) and a step of shrinking the yarn (10) by means of a shrinking system (2), further comprises precisely controlling the yarn tension and speed throughout the yarn shrinking process by means of at least one set of master rollers (5) located before or after the shrinking system (2). The tension is further controlled by sensors (7, 8) located between two sets of rollers (5, 6) or by automatically increasing the output speed of the creel (1), which is motorised or not.

Description

[0001] DESCRIPTION

[0002] ONLINE PROCESS AND MACHINE FOR SHRINKAGE OF TENSION-SENSITIVE YARNS

[0003] OBJECT OF THE INVENTION

[0004] The invention, as stated in the present descriptive memorandum, relates to an online process and a machine for shrinking tension-sensitive yarns, providing advantages and features, which are described in detail below.

[0005] The object of the present invention is, on the one hand, an online process for shrinking tension-sensitive yarns that, comprising the phases of yarn unwinding, shrinking, and yarn rewinding, and potentially including other stages such as drying, twisting, and winding, incorporates a stage of precise tension control. This significantly improves the quality of the final product by optimizing the fixing and shrinking processes of fabrics and yarns or fibers at low tension for yarns highly sensitive to tension and stretching. More specifically, an objective of the present invention is to introduce improvements in the treatment process of highly sensitive yarns that require a shrinking process under controlled tensions between 0 and 30,000 cN.

[0006] In turn, a second aspect of the invention relates to a machine for shrinking tension-sensitive yarns with said process improvements, ensuring that the shrinking is carried out with minimal or zero tension, for which, in addition to a creel and a shrinking system, and optionally a drying system and a twisting and winding system, it comprises at least one master cylinder group that controls the tension and speed of the yarn throughout the process, and may optionally include contact sensors and / or non-contact sensors to assist in said control.

[0007] FIELD OF APPLICATION OF THE INVENTION

[0008] The field of application of the present invention falls within the textile sector, focusing particularly on the field of the industry dedicated to the spinning and twisting of fibers and yarns or ropes, and more specifically on the shrinking processes.

[0009] BACKGROUND OF THE INVENTION

[0010] Ready-made textile garments may shrink during the daily washing process due to the application of temperature during the washing process.

[0011] In the textile chain there is a process after obtaining the fabric which consists of fixing the width of the fabric using machines called "RAM ES" which fix the width and subject to an online process of applying high-temperature steam that fixes the molecular structure of the fibers that make up the fabric.

[0012] This fabric treatment ensures that, once the garment is made, it will not shrink when washed.

[0013] Ongoing research in the textile sector, and especially in the development of new protein-based fibers—artificial, synthetic, or natural—aims to improve and streamline processes throughout the entire textile supply chain. One possible solution is to shrink the yarn or fibers on the spinning, twisting, or winding machine before weaving, thus shortening the textile process.

[0014] Currently, the possibility of introducing this in-line shrinking process is not considered in spinning, twisting, or winding machines.

[0015] The problem is that, for yarns that are particularly sensitive to tension and stretching, precise control is needed during the shrinking process, which can be by steaming or other types of temperature increase, such as infrared, LEDs, etc., so that the integrity of the yarn is maintained without compromising its mechanical properties.

[0016] Traditional machines do not provide adequate tension control at all stages of the process, which can result in a defective or unsuitable final product for specific applications such as weaving. Furthermore, they do not efficiently integrate shrinking, drying, twisting, and winding processes into a single production line. The objective of the present invention is to develop a process for achieving such tension control in sensitive yarns using a machine that, at a minimum, comprises a creel, a commercially available yarn shrinking system, a master cylinder group that controls the tensioning process, and a yarn take-up system via winding or twisting, which, for example, may be a ring system.

[0017] The process may also include other operations before or after the tension control stage performed by the master roller group, such as drying, impregnation, or other textile processes.

[0018] In any case, and as a reference to the current state of the art, at least on the part of the applicant, the existence of any process or machine that presents technical, structural and constitutive characteristics equal or similar to those claimed herein is unknown.

[0019] EXPLANATION OF THE INVENTION

[0020] The online process and the machine for shrinking tension-sensitive yarns proposed by the invention are configured as an optimal solution to achieve the objectives mentioned above, with the characterizing details that make it possible and that distinguish them conveniently included in the final claims that accompany this description.

[0021] Specifically, what the invention proposes, as previously mentioned, is an online treatment process for shrinking tension-sensitive yarns that, basically comprising the phases of yarn unfolding, shrinking and yarn collection, as well as preferably stages of drying, twisting and winding, is distinguished by comprising a stage of precise control of the yarn tension, which significantly improves the quality of the final product, optimizing the processes of fixing and shrinking fabrics and yarns or fibers, in particular with highly sensitive yarns, which require a shrinking process, under controlled tensions of between 0 and 30.000 cN, a second aspect of the invention being a yarn treatment machine where shrinkage is carried out in a controlled manner with minimal or zero tension, for which purpose it comprises at least a yarn feed creel, a shrinking system and a master cylinder group that controls the tension and speed of the yarn, and may also include a drying system and a twisting and winding system.

[0022] For this purpose, and more specifically, the yarn tension control stage during the shrinking process can be carried out in the steam machine in different ways or implementation options, specifically four:

[0023] Thus, in a first embodiment option, the shrinking system, which can be by steam or any other temperature increase system, can be placed between two groups of cylinders that continuously feed the yarn, where one of them is the master cylinder group, and which, optionally, is then connected to pass through a drying system and a yarn collection system, such as twisting, ring twisting, winding or other systems.

[0024] In this case, the shrinking system and a tension control element (contact or non-contact) are located between these two sets of cylinders. This element can consist of a commercially available sensor that captures the working tension signal of the yarn at any given time. This tension signal is sent to a PLC-type data control element, which, through a standard software program, sends the signal to each of the two sets of motorized cylinders. These cylinders may be controlled by a frequency converter to maintain a constant tension by varying the speed of one set of cylinders relative to the other, thus ensuring the desired or constant yarn tension. It should be noted that the master cylinder set can be located either before or after the shrinking system.

[0025] Normally, during the yarn shrinking stage, the tension increases, which is detected by the sensor that sends the signal to the control element that, in turn, connects with one of the groups of cylinders so that the motor associated with that group of cylinders reduces or increases the speed, thus lowering or raising the yarn tension to the desired level, which has been previously programmed in the PLC.

[0026] In a second option for tension control, similar to the one described above, the tension control element incorporates the use of optical means. This involves starting with the same arrangement described for the previous version, that is, with the shrinkage system located between two groups of cylinders that continuously feed the yarn, which can optionally be connected to a drying system and a yarn collection system such as winding or twisting using "yarn goes from the outside in" methods, such as ring twist technology compared to double twist TFO or 2x1.

[0027] In this case, a vision control element is positioned between these two groups of cylinders. This element consists of a commercially available optical sensor, either contact or non-contact, which captures the position of the thread at any given moment. When the thread passes a predetermined zone, one of the cylinder groups reduces or increases its speed to stop the thread at the desired position of minimum tension. This position is usually a resting position, such as a curve, when the minimum working tension is the goal.

[0028] During the yarn shrinkage stage, the yarn tends to move from a curved resting position to a straight position (due to the increased tension generated by the shrinkage), passing the position of the sensors that detect the shrinkage. These sensors send a signal to the PLC, which in turn sends a signal to the frequency converter, correcting the speed of one of the cylinder groups so that the yarn returns to its normal position between the two curved sensors. The position of these sensors can be adjusted to obtain greater or lesser sensitivity.

[0029] This way the thread shrinks, but always maintains the minimum resting tension, which is that of a slight curve, in case you want to work in line at the minimum tension.

[0030] As in the previous option, the master cylinder group can be either before or after the shrinking system.

[0031] In a third embodiment of the invention, the shrinkage is absorbed by applying a higher unwinding speed to the creel or bobbin frame where the yarn feed bobbin is located. If, instead of placing two sets of cylinders to control yarn tension, as in the two variants described above, only one set of master cylinders is placed between the take-up system and the shrinkage system, the shrinkage will cause the yarn to pull on the creel, increasing the yarn's exit speed from the bobbin onto the creel. Therefore, the creel automatically absorbs this increase or decrease in speed in a balanced manner and without any tension control element, with or without contact, thus maintaining the system in equilibrium.

[0032] It should be noted that the inclusion of a contact voltage control element, in itself, increases the system voltage, so if the aim is to shrink the thread without producing voltage, we are already increasing it.

[0033] In any case, what the invention proposes in this embodiment option is an integrated process that combines unfolding the yarn from the bobbin onto the creel, shrinking (through steam), drying (by infrared, LED or other means), impregnation and twisting of rings (or other systems) or winding of yarns, with a carefully controlled yarn tension between 0 and 30,000 cN.

[0034] For this purpose, in this case the machine capable of carrying out this process has only one group of feeding cylinders that acts as the master element for all operations, being located after the shrinking system.

[0035] More specifically, the invention generally proposes a process for controlling yarn shrinkage inline with tension control, which includes, at a minimum, a yarn unwinding stage with a bobbin unwinding system, a shrinking stage with a shrinking system, yarn speed control with at least one master roller group (downstream of the shrinking system), and a take-up stage with a yarn take-up system, which may be twisting, winding, or other methods. Other systems may exist between each of the aforementioned inline systems, such as drying, impregnation, or others known in the industry.

[0036] The key to the invention's process lies in performing the shrinkage stage with virtually no tension, preferably throughout the entire process, but especially during the yarn shrinkage stage. In the aforementioned third embodiment, the process involves absorbing the tension generated during shrinkage by the creel. That is, if the shrinkage line speed is approximately 60 meters per minute, shrinkage in the initial phase will cause the yarn to exit the creel at a higher speed, thus absorbing the increased yarn exit speed without any controlling element or cylinder. This is the basis for performing the shrinkage phase with almost 0 cN of tension.

[0037] Other stages may exist between those described, such as impregnation, drying, or others. There may also be other systems upstream or downstream of the feed or master cylinder groups, such as yarn collection systems like winding, twisting, etc.

[0038] Finally, in a fourth implementation option, as a variation of the third option, the use of a motorized bobbin thread deployment creel is considered.

[0039] In the case where the thread unwinds following the direction of the bobbin's axis — that is, with the bobbin rotating on its own axis — "route" — , the weight of the bobbin itself generates tension in the thread during unwinding.

[0040] This tension varies from high to low depending on the amount of yarn remaining. If the bobbin is full, the weight is greater because there are more meters, meaning more kilograms, that must be pulled by the master cylinder located after the shrink system. If we install a motorized creel, meaning the bobbin has a drive system that can control its speed relative to the master cylinder, we can control the tension.

[0041] When the yarn exits the bobbin perpendicular to its diameter, the bobbin can be rotated or not, imparting a twist effect in one direction or the other ("S" or "Z") to give the yarn more turns per meter than those generated by the yarn unwinding system, or to generate fewer turns, or even eliminate them. This also allows control of the yarn tension and twist to ensure a specific number of twists during the shrinkage stage, which can be set to "0".In short, the online process that is the subject of the invention, for shrinking tension-sensitive yarns, being of the type that comprises, as treatment stages, at least, those of unwinding the yarn, by means of a feed creel and shrinking the yarn, by means of a shrinking system, comprising or not comprising others, such as drying and collection stages, is distinguished essentially by the fact that it comprises a precise control of the tension and speed of the yarn during the entire yarn shrinking process by means of, at least, a group of master cylinders, which may be located before or after the shrinking system.

[0042] In one option of the process, tension control is carried out by means of contact or optical sensors which, located in an area of ​​the yarn that passes between two groups of cylinders, one of which is the master cylinder group, automatically adjust their relative speed to maintain constant yarn tension.

[0043] Preferably, automatic speed adjustment is performed by PLC that receives the signal from the sensors and is connected to the cylinder actuators.

[0044] Alternatively, tension control is performed at the yarn unwinding stage by automatically increasing the creel exit speed to absorb yarn shrinkage without the need for additional sensors or cylinders.

[0045] Optionally, tension control by means of automatic increase of the creel's exit speed is carried out by means of a motorized creel connected to the master cylinder group for tension control.

[0046] In any case, it is preferable to maintain a controlled voltage between 0 and 30,000 cN during all stages of the process.

[0047] DESCRIPTION OF THE DRAWINGS

[0048] To complement the description being made and in order to help a better understanding of the characteristics of the invention, this descriptive report is accompanied, as an integral part thereof, by sheets of drawings in which, for illustrative and non-limiting purposes, the following has been represented: Figure number 1.- Shows a schematic representation of an example embodiment of the machine for carrying out the online process of the invention, for the shrinking of tension-sensitive yarns, specifically in an option thereof comprising the creel, shrinking system, drying system and yarn collection system, and in which, as tension control, it only comprises a group of master cylinders after the shrinking system that pulls the yarn from the creel which may or may not be motorized, the path of the yarn along it being shown, represented by a dashed line; Figure number 2.Figure 3 shows a schematic representation of another option of the set of elements comprising the machine for controlling yarn tension, specifically an option comprising, between two groups of cylinders, one of them master, non-contact optical sensors as tension control elements, showing the arrangement of the yarn as it passes through the area of ​​the same, represented by a dashed line; Figure 3 shows a schematic representation of another option of the set of elements comprising the machine for controlling yarn tension similar to that shown in Figure 2, in this case comprising, between the two groups of cylinders, contact sensors as tension control elements; and Figure 4 shows again a schematic representation of all the systems comprising the machine of the invention, in this case in a more complete embodiment of the same, with the two groups of cylinders.

[0049] PREFERRED EMBODIMENT OF THE INVENTION

[0050] In view of the aforementioned figures, and in accordance with the numbering adopted, different examples of non-limiting embodiments of the machine for shrinking tension-sensitive yarns of the invention can be observed, which comprises what is described in detail below.

[0051] Thus, as can be seen in said figures, the machine (100) of the invention is an in-line yarn treatment machine (10) which, in a known manner, comprises at least a feed creel (1) and a shrinking system (2), for example by steam, without ruling out other means of increasing the temperature, and which may or may not comprise a drying system (3) and / or a collection system (4) with twisting and winding means.

[0052] And, based on this already known configuration, it is distinguished by the fact that it also includes, at least, a group of master cylinders (5) that controls the tension and speed of the thread (10) throughout the process.

[0053] In one embodiment, such as that shown in Figure 1, the master cylinder group (5) is incorporated after the shrinking system (2), acting in combination with the feed reel (1), which may or may not be motorized. However, the master cylinder group (5) can also be located before the shrinking system (2).

[0054] In another embodiment, the machine (100) comprises two groups of cylinders, one of which is the master cylinder group (5) and the other a driven cylinder group (6) between which the yarn (10) runs, with one or more sensors (7, 8) between them as means of controlling the yarn tension, which are linked to a PLC (not shown) which, in turn, controls the actuation of one or both of said cylinder groups (5, 6), so that the signal they send when detecting tension in the yarn (10) automatically activates the acceleration or decrease of the rotation speed of the cylinders and, consequently, the advance of the yarn (10) to reduce the tension.

[0055] The sensors can be contact sensors (7), as shown in the example in Figure 3, or they can be optical sensors (8) without contact with the wire (10), as shown in the example in Figure 2.

[0056] In short, the machine (100) of the invention is designed to control the shrinkage of the yarn (10) at minimum or controlled tension. This shrinkage is applied inline after the shrinking system (2) to the already shrunk yarn, which can then be twisted, wound, or subjected to any other stage. This is achieved by means of at least one master cylinder group (5) that controls the process, and may include another group of cylinders (6) that control the tension. It is important to note that the positions of these cylinder groups can be reversed; that is, the master cylinder group (5) can be located before or after the sensors (7).One industrial application of this process is the absorption of shrinkage in highly tension-sensitive protein fibers. In these cases, simply controlling the fiber with additional rollers or contact tension control methods introduces tension into the yarn that cannot be absorbed, altering its final properties or causing it to break. This method allows operation at minimal, almost zero, tensions, especially when the creel (1) absorbs the yarn shrinkage by increasing the exit speed.

[0057] Having sufficiently described the nature of the present invention, as well as the manner of putting it into practice, it is not considered necessary to make its explanation more extensive so that any expert in the field can understand its scope and the advantages that derive from it.

Claims

CLAIMS 1.- Online process for shrinking tension-sensitive yarns, comprising, as treatment stages, at least, yarn unwinding by means of a feed creel (1) and yarn shrinking (10) by means of a shrinking system (2), and comprising or not drying (3) and collection (4) or other stages, is characterized by comprising precise control of the tension and speed of the yarn throughout the yarn shrinking process by means of at least one group of master cylinders (5) located before or after the shrinking system (2). 2.- Online process for shrinking tension-sensitive yarns, according to claim 1, characterized in that the tension control is also carried out by means of sensors (7, 8) that are located in an area of ​​the thread that passes between two groups of cylinders (5, 6), one of which is the master cylinder group (5), and automatically adjust the relative speed of the same to maintain the tension of the thread constant. 3.- Online process for shrinking tension-sensitive yarns, according to claim 2, characterized in that the automatic adjustment of the speed of the cylinder groups (5, 6) is carried out by means of a PLC that receives the signal from the sensors (7, 8) and is connected to the actuators of the cylinders (5, 6). 4.- Online process for shrinking tension-sensitive yarns, according to claim 1, characterized in that the tension control is carried out in the yarn unwinding stage by automatically increasing the creel exit speed (1) to absorb the yarn shrinkage. 5.- Online process for shrinking tension-sensitive yarns, according to claim 4, characterized in that the tension control carried out by the automatic increase of the creel's exit speed (1) is performed by means of a motorized creel (1) connected to the master cylinder group (5) for tension control. 6.- Online process for shrinking tension-sensitive yarns, according to any of the preceding claims, characterized in that, by means of at least said group of Master cylinders (5) maintain a controlled tension between 0 and 30,000 cN during all stages of the process.

8. Machine for shrinking tension-sensitive yarns, by means of a process as described in any of claims 1 to 6, comprising at least a feed creel (1) and a shrinking system (2), characterized by further comprising at least a master cylinder group (5) that controls the tension and speed of the yarn (10).

9. Machine for shrinking tension-sensitive yarns, according to claim 8, characterized in that the master cylinder group (5) is incorporated after the shrinking system (2) acting in combination with the feed creel (1). 10.- Machine for shrinking tension-sensitive yarns, according to claim 9, characterized in that the creel (1) is motorized. 11.- Machine for shrinking tension-sensitive yarns, according to claim 8, characterized in that the master cylinder group (5) is incorporated before the shrinking system (2).

12. Machine for shrinking tension-sensitive yarns, according to claim 8, characterized in that it comprises two groups of cylinders, one of which is the master cylinder group (5) and the other a driven cylinder group (6) between which the yarn (10) runs, there being between both one or more sensors (7, 8) as means of controlling the yarn tension, linked to a PLC which, in turn, controls the actuation of one or both of said cylinder groups (5, 6). 13.- Machine for shrinking tension-sensitive yarns, according to claim 12, characterized in that it comprises contact sensors (7).

14. Machine for shrinking tension-sensitive yarns, according to claim 12, characterized in that it comprises optical sensors (8) without contact with the yarn (10).

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