Compact module for wet spinning of chemical fibers

Abstract

To provide a module for wet spinning of chemical fibers, which has a particularly compact layout, and is suitable for spinning of a reduced number, e.g., from 2 to 8 low-count tows of chemical fiber filaments.SOLUTION: A compact module for wet spinning of chemical fibers of the type comprises: a spinning head F of 2-8 tows S, each one consisting of a plurality of continuous filaments; relative supply pumps P of the spinning solution; a coagulation tank V containing a coagulation solution; and a plurality of drive rollers 2 and respective idle diverter rollers 3 which determine a zigzag path of the tows S downstream of the spinning area, wherein in the rectilinear lengths of which liquid-based treatments are carried out on the tows S. The rectilinear lengths of the zigzag path are horizontal, and the liquid-based treatments on the tows S are carried out in horizontal treatment trays 4 of the spillway type.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a module for the wet spinning of chemical fibers. In particular, the invention relates to a module of this type with a particularly compact layout suitable for spinning low-count tows of chemical fiber filaments with a reduced number, for example 2 to 8, preferably 4 to 6. Among these, artificial fibers such as rayon or lyocell, or synthetic fibers such as acrylic fibers (PAN), meta-aramid fibers (NOMEX®) and para-aramid fibers (KEVLAR®, TWARON®), are used in the textile or technical textile sector, and in the case of acrylic fibers, are also used as precursors in the production of carbon fibers. [Background technology]

[0002] In-line spinning process In the production of chemical fibers, the spinning process can be divided into two main families: in-line processes with horizontal development and in-line processes with vertical development.

[0003] In-line processes with horizontal development process a large number of parallel tows (from 6 to 240 depending on the count), each consisting of a very variable number of filaments (from 30 to 400,000), usually at fairly low speeds (up to 500 m / min). In fact, these are processes mainly used for the spinning of non-melting materials, in particular for the production of acrylic or modacrylic fibers, which can be spun by dissolving them in a suitable solvent and then extruding the spinning solution in a suitable aqueous solution, where coagulation occurs upon solvent removal. The movement of the filaments that are formed in the aqueous coagulation liquid is a particularly critical step, which therefore severely limits the maximum speed of the process.

[0004] This type of process also uses relatively low processing speeds to reduce the risk of tow instability and breakage during processing. Indeed, because the tows are horizontally and closely spaced, if one breaks, it will cause failure of all adjacent tows, often requiring the entire line to be stopped, causing serious damage to production.

[0005] Typically, in-line processes with modular vertical expansion—even simple modular processes without significant height expansion, such as the (less common) continuous spinning of rayon—process much fewer tows per module (up to 12), and the number of filaments in each tow is significantly lower than those found in horizontal processes (e.g., up to 300), but the processing speeds are much higher (up to 6,000 m / min). Nevertheless, even in this type of process, multiple spinning assemblies (up to 96 in-line for POY yarns) can be used to provide a single spinning line, resulting in higher overall production capacities. This second type of process is generally used for spinning thermoplastic fibers that solidify very quickly upon cooling, thus allowing for much faster spinning without compromising the integrity of individual filaments. Naturally, the higher the speed, the greater the chance of breakage in these processes, since spinning at higher speeds implies a more critical spinning process anyway. However, in this case, a single tow breakage does not damage more than a few adjacent tows.

[0006] In practice, for example, in the rayon industry, horizontal lines are known that produce 160 continuous tows of 170 denier, each consisting of 80 filaments. If one tow breaks before reaching the desired length and the horizontal line is consequently interrupted, 160 reels may be stopped. These reels are classified as second-grade as incomplete, resulting in significant economic losses. In many cases, it takes a day to collect a complete reel, which reduces the daily reel production.

[0007] Alternatively, it is known that the same quantity and type of tow could be produced in 40 four-tow modules, collecting a total of 160 tows on each module's four reels. If a single tow breaks, at most three more adjacent tows will be affected, resulting in a drop of only 2.5% of daily production, rather than 100% as considered above.

[0008] If the spinning process is aimed at producing thick fiber tows, the production capacity of horizontally deployed lines can reach more than 20,000 tonnes per year for the production of acrylic or modacrylic fibers, with a total fiber count of 900 ktex, divided into tows of up to 150 ktex each.

[0009] If a similar, very costly line layout were instead used to produce much smaller tows, such as the smallest commercial standard 1K (1,000 filament) tows of carbon fiber precursor acrylic fiber with a count of approximately 900 / 1550 dtex (this size is particularly in demand in certain technical applications, such as the aerospace industry), the line's capacity could be significantly reduced by up to approximately 60 times. In fact, for process reasons, a horizontal line with a maximum width of 1.8 meters cannot accommodate more than 100 tows. Therefore, the total count produced would be approximately 15 ktex. Furthermore, the breakage of a single tow can, in certain circumstances, sever dozens of additional tows, necessitating a plant shutdown. Therefore, producing small tow sizes is completely uneconomical in a conventional in-line production plant with horizontal expansion.

[0010] Module Spinning Process The problem of inexpensively producing small-sized tows has been successfully addressed by WO 2013 / 014576, also in the name of the applicant, which discloses a spinning process using modules. Each module handles a small number of tows, e.g., 2 to 8 tows, and moves the tows along a linear zigzag path extending over the height of the individual module between drive and diverter rollers pivotally mounted on the module walls. While on these paths, the yarn undergoes all necessary treatments, such as subsequent washing, finishing, and drawing, to become the final yarn. The desired plant productivity can be achieved by arranging a sufficiently large number of individual adjacent modules in series, and collecting the fiber tows emerging from each module into a single ribbon of large width, which is then sent directly to the oxidation and carbonization process.

[0011] The total productivity of this type of process can be freely adjusted, as already mentioned, by simply adding the required number of modules to the plant. The special layout of this process therefore compensates for the significant discontinuity of the conventional layout of spinning lines for acrylic fibers for textiles or as precursors to carbon fibers, and offers significant advantages over the conventional layout in terms of versatility and space occupation when working in the production of low count yarns.

[0012] The problem underlying the present invention As recalled above, although the modular spinning process disclosed in WO 2013 / 014576 has significant advantages in producing tows of low count yarns, such a process also has several drawbacks that have hitherto limited its application in the production of PAN fibers as precursors for producing carbon fibers.

[0013] The first drawback is related to the conventional configuration of washing and finishing treatment of fiber tows, which is proposed in this specification for a washing / finishing device arranged along a straight section of the zigzag path of the spinning module. In fact, this configuration consists of a first pair of inlet rollers that shifts the path of the tows in the treatment tray, and then a second pair of rollers that causes the tows to exit from the same tray. Within the treatment tray, thanks to an appropriate inclination of the treatment tray, the upstream flow of the washing liquid is maintained by gravity, and the upward dragging force caused by the tows slows down the downward movement of the washing liquid by gravity.

[0014] Conventional solutions of this type have several negative effects. First, the necessarily small diameter of the inlet and outlet roller pairs leads to sharp offsets, which cause high local stresses in the passing tow. These stresses can cause anisotropy of the individual filaments and therefore impair their quality. Second, the inlet and outlet roller pairs constitute a series of obstacles, which slows down and greatly complicates the tow drawing operation. A final negative effect is that the inclined arrangement of the zigzag path, which is essential to provide the hydraulic head required for the washing device, takes up a lot of vertical space, resulting in an increase in the overall height of the spinning module.

[0015] A second drawback of known spinning modules is instead related to the winding pattern of the tow onto the corresponding drive roller. This winding pattern must always start from the bottom of the roller and unfold towards the top, due to well-known technical requirements for the drawing step. To achieve this winding pattern, in known spinning modules, subsequent drive rollers are arranged with a progressively outward offset relative to the horizontal, so that the tow unwound from the top of the previous roller is aligned with the bottom of the next roller. This arrangement therefore significantly affects the overall width of the spinning module and, therefore, indirectly, the productivity of a plant with the same footprint. On the other hand, if one tries to minimize the module width, winding only one complete coil of tow onto the drive roller and the respective diverter roller impairs the effective drawing action along the zigzag path. It usually turns out that a single winding on a drive roller is insufficient to allow for large speed changes without sliding between two consecutive drive rollers.

[0016] The problem underlying the present invention is therefore to specify a spinning module that is more compact in terms of both width and height with respect to the spinning modules of the known art, and which, in addition, accommodates washing and finishing devices and does not cause abrupt deviations of the tow in its zigzag path between the drive rollers.

[0017] Within the framework of this general problem, a first object of the present invention is to provide a cleaning device that does not have a tow diverter roller in the processing tray.

[0018] A second object of the present invention is to provide a cleaning device that can be installed in a horizontal position, taking up less space vertically and reducing the overall height of the spinning module.

[0019] Finally, a third object of the present invention is to modify the path of the tow on the drive rollers, making it possible to assemble such drive rollers in a fully overlapping position rather than in a horizontally offset position, thereby minimizing the horizontal space occupied by said rollers and thereby reducing the overall width of the spinning module. Summary of the Invention

[0020] This problem is solved and these objects are achieved by a compact wet spinning module having the features defined in claim 1. Further preferred features of such a spinning module are defined in the dependent claims. [Brief explanation of the drawings]

[0021] Further features and advantages of the compact spinning module according to the invention will become more apparent from the following detailed description of preferred embodiments of the invention, which are in each case given purely by way of non-limiting example and are illustrated in the accompanying drawings, in which: [Figure 1] 1 is a perspective overall view of a compact spinning module according to the present invention; FIG. [Figure 2] FIG. 2 is a front view of the compact spinning module of FIG. 1. [Figure 3] FIG. 2 is a side view of the compact spinning module of FIG. 1. [Figure 4] FIG. 1 is an enlarged top view of the first processing tray and respective feed rollers, showing the path of the tow being processed. [Figure 5] 5 is an enlarged top view similar to FIG. 4, but also showing a second processing tray below the first processing tray, having an opposite inclination to the first processing tray relative to the support plate of the drive roller. [Figure 6] FIG. 2 is a further enlarged cross-sectional view of a two-step processing tray according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] According to the present invention, in order to solve the above-mentioned problems, a compact spinning module is proposed in which the zigzag path of the tow between the drive rollers provides horizontal straight sections between subsequent drive rollers, and the processing or finishing trays arranged along said path are of the spillway type, so that no offset of the tow is required for the straight path from one drive roller to the next.

[0023] Furthermore, all the drive rollers are pivotally mounted on the same vertical support plate so that they overlap completely in the horizontal plane, while the offset of the tow in the delivery direction from the top of one roller to the bottom of the next roller is obtained by varying the inclination of the axes of the drive rollers and the corresponding diverter rollers relative to the direction perpendicular to the support plate.

[0024] General Layout The general layout of a compact spinning module according to the invention is clearly shown in Figures 1 to 3 and comprises a sturdy mesh frame T made of steel cross-members welded or bolted to one another, to which the functional elements of the module are fixed. These functional elements include a spinning head F producing a limited number of low-count tows S of 2 to 8, preferably 4 to 6, continuous filaments, a corresponding feed pump P for the spinning solution, and a coagulation tank V containing a coagulation liquid. From the coagulation tank V, a tow S of spun and coagulated filaments is unwound. This tow must then be treated with aqueous wash and finish solutions to remove the solvent and give the filaments the desired qualities.

[0025] According to the invention, for this purpose, the tow S is fed onto a series of drive rollers 2 and corresponding diverter rollers 3, all of which are pivotally mounted on the same vertical support plate 1, integral with the frame T, and are aligned adjacent to two opposite vertical sides of said support plate 1, on two respective vertical lines. The drive rollers 2 are arranged to define a zigzag path for the tow S, which unfolds over the entire extension of the support plate 1. According to a first important feature of the invention, the individual sections of such a path are arranged in overlapping horizontal planes, which means that the drive rollers 2 are arranged on the plate 1 so that the upper end of one drive roller 2 is at the same height as the lower end of the next drive roller 2, thereby optimizing the use of the available space on the plate 1, as clearly shown in Figures 1 and 2. The diverter rollers 3 are arranged next to each drive roller 2, have a smaller diameter, and are pivotally mounted loosely on the same support plate 1. The diverter rollers 3 are used, in a known manner, to form one or more coils of windings of the tow S on the drive rollers 2, thereby increasing the frictional force that each drive roller 2 can impart to the tow S being processed.

[0026] Along the horizontal sections of the zigzag path extending between successive pairs of drive rollers 2, processing trays 4 with lateral spillways are housed, in which the tow S is washed and finished. In the illustrated embodiment, six drive rollers 2 and the same number of processing trays 4 are provided. Each such processing tray 4 is positioned completely horizontally and aligned with the upper end of the previous drive roller 2 (from which the tow S is delivered) and the lower end of the next roller 2 (where the tow S is received). The final processing tray 4s, located higher on the support plate 1, is instead followed by a pair of drawing rollers 5 housed in the lateral extension 1a of the support plate 1. The drawing rollers 5 determine the final spinning speed of the tow S and feed it to a winder (not shown) below, which collects the tow S made of fully processed fibers onto a spool, in a known manner.

[0027] Alternatively, if the treated fibres are PAN fibres intended to be used directly as precursors for producing carbon fibres, the tow S coming out of the drawing roller 5 is treated in an underlying vertical steam drawing device and then sent directly and continuously to an oxidation and carbonisation plant in the manner already described in the cited WO 2013 / 014576.

[0028] Drive Roller and Orientable Diverter Roller According to another feature of the invention, in order to be able to obtain the desired winding of the tow S on the drive rollers 2 and the respective idle diverter rollers 3, starting from the bottom of such rollers and proceeding to the free top, the orientation of the axes of the drive rollers 2 and diverter rollers 3 is laterally adjustable within a preset angle of up to 10° with respect to a direction perpendicular to the support plate 1, although all of these drive rollers 2 and diverter rollers 3 are pivotally mounted on the same vertical plane consisting of the support plate 1, with such axes always lying in a horizontal plane. Indeed, during tests carried out, the Applicant has been able to verify that, despite the fact that such tows S move in an oblique direction with respect to the support plate 1 as they move from the top of one drive roller 2 to the bottom of the next drive roller 2, it is possible to obtain a very stable arrangement of the tow S being wound on the drive rollers 2 only if the axes of the receiving drive rollers 2 are oriented perpendicular to the receiving direction of the tow S. At the same time, the axis of each diverter roller 3 must converge with the axis of its respective drive roller 2 in a direction away from the support plate 1 in order to wind appropriately spaced subsequent coils of tow S onto the surface of the drive roller 2, as clearly shown diagrammatically in Figures 3, 4 and 5.

[0029] The horizontal adjustability of the lateral tilt of the shaft of the drive roller 2 and of each diverter roller 3, i.e., the attitude of the shafts, is preferably achieved by means of a cylindrical joint (not shown). This joint allows the attitude of the shafts to be adjusted when the joint is in a loose position, and in return maintains the shafts at a preset tilt when the joint is tightened. It is therefore clear that the pivotal attachment of the drive roller 2 and the diverter roller 3 to the support plate 1, as mentioned at the outset, is not directly on said plate 1, but rather via the cylindrical joint. The outer half of this joint is integral with the support plate 1, while the inner half actually carries the pivots of the rollers 2 and 3. Advantageously, the motor M, which drives the rotation of the drive roller 2, is rigidly coupled to the drive roller 2 on the same axis, so that the entire motor M / drive roller 2 assembly oscillates laterally about the pivots housed in the respective support cylindrical joints.

[0030] Two-step processing tray The structure of the processing tray 4 is shown in detail in FIG. 6, where a schematic cross-sectional view thereof is shown, while the fixing system of the processing tray 4 to the support plate 1 is clearly shown in FIGS.

[0031] The processing tray 4 is designed to treat the tow S with an aqueous solution for cleaning, solvent extraction, and / or finishing (hereinafter, for simplicity, also referred to simply as "cleaning liquid" or "processing solution" or "processing liquid"). This cleaning liquid is supplied to a washing area 11 having two opposing spillways W, so that the tow S can be uniformly wetted with the aqueous processing solution without having to shift the tow S relative to the straight, horizontal section of the zigzag path of the tow S between two successive drive rollers 2.

[0032] More specifically, in the preferred embodiment shown in FIG. 6, each processing tray 4 includes two subsequent cleaning steps, each of which: a cleaning liquid inlet 10; a washing area 11 comprising two opposing lateral spillways W, the bottom of which is provided with a surface finish suitable for promoting turbulence of the washing liquid passing through it; - two main outlets 12 for the washing liquid, which collect the washing liquid coming out of the two opposing spillways; and finally additional outlets 13 for cleaning liquid, which collect the drops coming from the tow S coming out of the cleaning area 11 and are arranged immediately downstream of each main outlet 12 in the direction of travel of the tow S represented by the arrows F;

[0033] While in its path through the processing tray 4, the tow S is guided by entrance and exit rollers 6, which may be grooved to precisely guide the tow S. Additionally, if the tow assumes a deformed pattern as it is wetted with cleaning fluid, the tow S may rest on the cylindrical support 7. The cylindrical support 7 also aids in dripping from the tow S as it emerges from the spillway W. It should be noted that the rollers 6 and cylindrical support 7 do not alter the natural linear path of the tow S, and therefore apply very low stress to the tow S, sufficient to maintain the tow S perfectly centered on the processing tray 4 without causing filament degradation.

[0034] The inlet 10 and outlets 12-13 are connected by flexible pipe circuits (not shown) to the respective supply and return points and to the respective working pumps, which are arranged so that fresh processing solution is fed to the first washing zone 11 of the processing tray 4s located higher on the support plate 1, and successively the processing solution leaving one washing zone 11 is fed to the next washing zone in the order from top to bottom, countercurrent to the direction of travel of the tows S from bottom to top. However, within each washing zone 11, the washing operation is preferably accomplished, at least to a large extent, in a cocurrent flow with respect to the direction of travel of the tows S. In fact, if the opposite were true, the high dragging forces that would move the tows S on the washing liquid would prevent a uniform flow of the washing liquid in the desired direction.

[0035] The correct positioning of the processing tray 4 on the support plate 1 is determined by the interaction between two rigid arms 8 protruding from the bottom of the processing tray 4 and hinged to it, and two angled joints 9 integrated into the support plate 1. Each of the angled joints 9 is fitted to a corresponding hole on the plate 1 and has a through-hole that can accommodate and firmly secure the rigid arm 8. By loosening the angled joints 9, the rigid arms 8 of the processing tray 4 can be displaced and angled separately in their seats to change the position of the processing tray 4 relative to the support plate 1 until the plate precisely overlaps the zigzag path of the tow S in the particular path section under consideration. Once this position is determined, tightening the angled joints 9 securely fixes the processing tray 4 in the desired position. Of course, during this adjustment, there is no need to change the hydraulic connections of the processing tray 4, which are flexible and can follow the movement of the processing tray 4.

[0036] From the above, it is further noted that the processing trays 4 have different layouts depending on which side they receive the tow on: they will therefore have the layout shown in Figure 6 if they receive the tow from the left side, as seen by a viewer of the compact spinning module of the present invention, and instead will have a completely mirrored layout if they receive the tow S from the right side.

[0037] Finally, due to the arrangement of the tows S on the drive rollers 2 already described above, the processing trays 4 are inclined with respect to the vertical plane of the support plate 1, with their tow-receiving ends being located further away from the support plate 1 (to the right in FIG. 4 ) and their tow-delivery ends instead being closer to the support plate 1 (to the left in FIG. 4 ). However, since the tows S reverse their direction of travel in the zigzag path after each drive roller 2, it is clear that the processing trays 4 are inclined alternately with respect to the opposite side, as shown diagrammatically in FIG. 5 . However, here, for the sake of simplicity, only two trays 4 are shown.

[0038] In an alternative layout useful for reducing the number of flexible hydraulic connections connected to the processing tray 4, the terminal portion of the supply pipe of the cleaning area 11 is advantageously formed within the rigid arm 8 using a sealed hinge arrangement at the connection between said rigid arm 8 and the body of the processing tray 4.

[0039] Advantages of the compact spinning module of the present invention From the above description it is clear how the compact spinning module of the present invention fully achieves all of the set objectives and thus completely solves the technical problem underlying the present invention by means of a very simple and effective technical solution. Indeed, the compact spinning module of the present invention is highly versatile in use, as the module can be easily adapted to the spinning of various types of fibers requiring different spinning speeds, drawing conditions and types of treatment, thus significantly expanding the field of use of the spinning module. Indeed, since the space previously occupied by the spinning solvent is freed up, it is easily possible to increase or decrease the number of coils of the winding of the tow S on the drive roller 2 and the relative diverter roller 3, for example with one full coil, or preferably with two full coils, or even more preferably with three full coils, depending on the degree of drawing that is desired to be given to the tow S during the washing and / or finishing operations in order to increase the fiber density. The position of the processing tray 4 can then be quickly adapted to various transfer positions of the tows S on the drive roller 2 by loosening the angled joints 9 and pulling the processing tray 4 directly into its new correct position, with the tows S carefully centered directly over the processing tray 4 and throughout its extension, while the rigid arms 8 automatically adapt to the new position of the processing trays 4 and slide within the receiving cavities of the respective angled joints 9 to change their angular position.

[0040] Furthermore, by arranging the processing path between the subsequent drive rollers 2 horizontally, the height of the spinning module can be reduced to the maximum, while by arranging the drive rollers 2 completely overlapping on the same single vertical support plate 1, the width of the spinning module can be made compact, thereby achieving the desired objective of providing a very compact spinning module, which can therefore be made significantly less bulky than conventional horizontally deployed lines.

[0041] Finally, the use of treatment trays 4 with washing areas with two opposing spillways avoids abrupt shifts of the tows at the beginning and end of each washing and finishing step, thereby improving the quality of the resulting fiber and making the operation of drawing in the tows S at the start of the spinning process much easier and faster. Depending on the type of fiber to be processed, all treatment trays 4 of the compact spinning module of the invention can be fully dedicated to the washing and solvent removal operation, or some can be dedicated to this operation, with the remaining parts being dedicated to fiber finishing, for example, only the last two upper treatment trays or the last treatment tray. Also, depending on the type of fiber to be processed, all treatment trays can have two different treatment steps as described above with reference to the drawings, or alternatively, they can have a single, longer treatment step and are therefore suitable for different types of processing in a very flexible manner.

[0042] A further general advantage offered by the treatment tray 4 proposed in the spinning module of the present invention is finally the use of very small amounts of washing liquid, as a result of which particularly effective washing conditions can be easily obtained, i.e. washing conditions with a high exchange rate of the washing liquid and very rapid changes in the concentration or composition of the washing liquid.

[0043] However, the present invention should not be considered limited to the particular arrangements exemplified above, which constitute only exemplary embodiments of the present invention, but it is understood that different modifications, all within the purview of those skilled in the art, are possible without departing from the scope of protection of the present invention, which is defined solely by the following claims.

Claims

1. 1. A compact module for wet spinning of chemical fibers, comprising a spinning head (F) for a limited number of tows (S), each consisting of a plurality of continuous filaments, a pump (P) for supplying the spinning solution relative to the tow, a coagulation tank (V) containing the coagulation liquid, and a plurality of drive rollers (2) and respective idle diverter rollers (3) that define a zigzag path for the tows (S) downstream of the spinning zone, the zigzag path comprising a straight section in which a liquid-based treatment is applied to the tows (S), characterized in that the straight section of the zigzag path is horizontal and the liquid-based treatment to the tows (S) is applied in a horizontal treatment tray (4) of the spillway type.

2. 2. The compact module for wet spinning of chemical fibers according to claim 1, wherein the straight section of the zigzag path of the tow (S) extends between the upper end of one drive roller (2) and the lower end of the next drive roller (2).

3. 3. A compact module for wet spinning of chemical fibers according to claim 2, wherein the zigzag path of the tow (S) comprises windings of at least one full coil, preferably at least two full coils, more preferably at least three full coils on each drive roller (2) and each diverter roller (3).

4. 4. A compact module for wet spinning of chemical fibers according to claim 3, wherein the drive rollers (2) and the diverter rollers (3) are all pivotally mounted on a single vertical support plate (1).

5. 5. The compact module for wet spinning of chemical fibers according to claim 4, wherein the drive roller (2) and the diverter roller (3) are aligned on two respective vertical lines near two opposite vertical sides of the support plate (1).

6. 6. The compact module for wet spinning of chemical fibers according to claim 5, wherein the orientations of the axes of the drive roller (2) and the diverter roller (3) are adjustable in a horizontal plane at a preset angle around a direction perpendicular to the support plate (1).

7. 7. A compact module for wet spinning of chemical fibers according to claim 6, wherein the adjustment range of the attitude of the axes of the drive roller (2) and the diverter roller (3) is obtained by using a cylindrical joint, the outer half of which is integral with the support plate (1) and the inner half of which carries the pivots of the drive roller (2) and the diverter roller (3), and the cylindrical joint can be fixed in any desired position.

8. 8. A compact module for wet spinning of chemical fibers according to claim 7, wherein each of the drive rollers (2) is provided with a respective electric motor (M) rigidly coupled on the same axis, and the entire motor (M) / drive roller (2) assembly is oscillable laterally around the cylindrical joint carrying the pivot of the drive roller (2).

9. 7. A compact module for wet spinning of chemical fibers according to claim 6, wherein each horizontal section of the zigzag path of the tow (S) has an inclined direction relative to the support plate (1) from the upper end of a delivery drive roller (2) to the lower end of the subsequent receiving drive roller (2), the axes of the receiving drive rollers (2) also being oriented in the horizontal plane perpendicular to the above-mentioned inclined direction of the horizontal section of the zigzag path of the tow (S).

10. 10. A compact module for wet spinning of chemical fibers according to claim 9, wherein the axis of each diverter roller (3) converges with the axis of the respective drive roller (2) in a direction away from the support plate (1) in order to wind the subsequent coil of the tow (S) onto the surface of the drive roller (2) at an appropriate distance, also in the horizontal plane.

11. 11. The compact module for wet spinning of chemical fibers according to claim 4, wherein the treatment tray (4) includes at least one washing area (11) with two opposing spillways (W), and the tow (S) is uniformly wetted by the treatment liquid supplied to the washing area (11) without forcing the tow (S) to make a detour around the section of the straight and horizontal path between the two drive rollers (2).

12. Each of said processing trays (4) comprises at least one, preferably two processing steps using a processing liquid, and each of said processing trays (4) comprises: - said washing area (11) comprising two opposing spillways (W) and having a bottom surface that promotes turbulence of the treatment liquid; an inlet (10) for said treatment liquid into said washing zone (11); - two main outlets (12) for the treated liquid, respectively collecting the treated liquid emerging from the two opposite spillways (W); The compact module for wet spinning of chemical fibers according to claim 11, comprising:

13. 13. The compact module for wet spinning of chemical fibers according to claim 12, further comprising additional outlets (13) for the treatment liquid for collecting drippings from the tow (S) unwound from the washing area (11), the additional outlets (13) being arranged immediately downstream of each main outlet (12) in the traveling direction (F) of the tow (S).

14. 14. The compact module for wet spinning of chemical fibers according to claim 13, wherein the processing tray (4) is fixed to the support plate (1) in an adjustably manner by means of rigid arms (8) protruding from the lower part of the processing tray (4) and hinged thereto, the rigid arms (8) cooperating with respective angled joints (9) having through cavities in which corresponding rigid arms (8) are received and fastened, the angled joints (9) corresponding to holes on the support plate (1) being integral with the support plate (1).

15. 15. The compact module for wet spinning of chemical fibers according to claim 14, wherein the processing tray (4) has an inclined direction with respect to the vertical plane of the support plate (1), and the receiving end of the processing tray (4) that receives the tow (S) is further away from the support plate (1) than the discharging end of the processing tray (4) that discharges the tow (S), and the inclined direction coincides with the corresponding horizontal section of the zigzag path of the tow (S), so that the processing trays (4) are inclined alternately on opposite sides in subsequent horizontal sections of the zigzag path of the tow (S).

16. 16. The compact module for wet spinning of chemical fibers according to claim 14, wherein the inlet (10), the main outlet (12) and the additional outlet (13) of the treatment liquid are connected by flexible pipe circuits to respective supply, return and circulation pumps, the circuits being adjusted so that fresh treatment liquid is sent to the washing zone (11) of a treatment tray (4s) located higher on the support plate (1) and successively the treatment liquid emerging from one washing zone (11) is supplied to the next washing zone (11) in a countercurrent sequence to the direction of travel of the tow (S) along the zigzag path.

17. 17. A compact module for wet spinning of chemical fibers according to claim 16, wherein the end of the supply pipe of the washing area (11) is formed in the rigid arm (8).

18. The tow (S) is made of artificial fibers such as rayon and lyocell, or synthetic fibers such as acrylic, meta-aramid, and para-aramid fibers, according to any one of claims 1 to 17, a compact module for wet spinning of chemical fibers.

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