APPARATUS FOR THE DYEING OF YARN HANKS IN SHORT BATH AND THE DRYING THEREOF

Abstract: In a casing or case (1) for the dyeing and drying, a rotor (9, 12, 16) with horizontal axis can be driven at differentiated speeds and has a central manifold body (14) from which horizontal hollow arms (18) project from opposite sides, said arms (18) being shaped to bear the hanks and having perforated walls; a circuit (12, 14, 18) of air under forced circulation feeds said manifold (14), and causes discharge of air from perforated walls to make same air invest the yarn hanks fitted on and supported by said arms (18); from the bottom (1A) of the casing the liquid is driven to invest the hanks yarn.

Description: The invention refers to an apparatus for dyeing of yarn hanks in a short bath and the drying thereof, comprising a casing for delimiting the space for the dyeing and drying, a circuit for the circulation of liquid from the bottom of said casing to make same liquid invest the yarn of the hanks, and a rotor rotating about a horizontal axis, said rotor comprising means for supporting the yarn hanks. An apparatus of this type is disclosed in FR-A-2177237. This known apparatus comprises a rotor provided with an annular space wherein the material to be dyed is inserted. Dyeing is carried out by centrifugation, the dye being supplied from the center of the rotor. The rotational speed of the rotor causes a radial outward movement of the dyeing bath, in such a way that it crosses the whole material to be treated. This kind of dyeing gives poor results as the material is compressed by the centrifugal forces, thus obstructing the passage of the liquid. Moreover, compared with its overall dimensions, this known apparatus offers only little room for the material to be treated. Furthermore, the apparatus must be disassembled in order to insert or take out the material prior or after dyeing thereof. A short-bath dyeing process is a process in which the yarn is dyed with a limited amount of liquid which is repeatedly recycled. After dyeing, the yarn is dried partly through a centrifugation effect and partly through evaporation by means of hot air circulation. At present the dyeing of the yarn is performed in a first apparatus, while drying is completed in a different apparatus, so that transfer of the yarn hanks is required. This is the case in FR-A-2177237, where no hot-air drying is provided. From EP-A-0202348 a dyeing apparatus is known, where yarn hanks are supported by material bearing arms and placed in a dyeing tank. After dyeing, the yarn hanks must be removed from the tank and placed in a suitable drying machine. The object of the present invention is to provide an apparatus of the above mentioned type, which overcomes the drawbacks of the known apparatuses. In particular, it is an object of the invention to provide an apparatus which allows a complete dyeing and drying cycle to be performed in the same apparatus, thus avoiding the need of transferring the hanks from a first dyeing apparatus to a second drying apparatus. These objects are achieved according to the invention with an apparatus according to the preamble of claim 1, further characterized in that said rotor is provided with a central manifold supporting hollow arms disposed about the rotation axis of the rotor and which project from opposite sides of the rotor, are shaped to support hanks of yarn and present perforated walls; that a circuit of air under forced circulation is provided, supplying said manifold and causing discharge of air from the perforated walls of said arms to make said air invest the yarn hanks fitted on and supported by said hollow arms, and that program means are provided to put in action the slow rotation of the rotor and the liquid circuit, then the fast rotation of the rotor for centrifugation and, afterwards, the slow rotation of the rotor and the air circuit to complete the drying. Said air circuit may comprise a duct coaxial with the rotor, supplied from the outside and leading into the manifold. Alternatively, said air circuit may comprise a stationary annular manifold surrounding the rotor manifold, and passages corresponding to one another in said two manifolds for a centripetal directed supply to the rotor manifold. The circuit for the liquid circulation may comprise a duct coaxial with the rotor supplying ducts in the rotor which are provided with nozzles for investing the yarn hanks. Alternatively, the circuit for the circulation of liquid may comprise stationary overflowing vats (that is small basins) which generate curtains of falling liquid that are intercepted by the hanks kept in motion by the rotor. In practice said overflowing vats are disposed at a level higher than that of the rotor and at an intermediate level with respect to the rotor, between the horizontally projecting arms. The invention will be better understood by following the description and the attached drawing, which shows a practical non-limitative exemplification of the same invention. In the drawing: Figs.1 and 2 show, very schematically, an axial section and a cross section of a first embodiment of the apparatus according to the invention; Fig.3 shows a modified embodiment with respect to what is illustrated in Fig.1; and Figs.4 and 5 show, very schematically, a further embodiment in an axial section and in a cross section. According to what is illustrated in the attached drawing, and reference being made firstly to Figs.1 and 2, numeral 1 indicates the apparatus casing or case inside which both the dyeing and a possible washing, and the drying by centrifugal effect and then by the effect of the hot air circulation, are carried out. The casing 1 has a bottom 1A for the collection of liquid which, from a sump 3 may be pushed by a pump 5 up to a manifold 7 allowing the feeding of a coaxial duct 9 which rotates together with a rotor located inside the casing 1. The rotor is developed with the axial duct 9 for a circuit of liquid and with an axial duct 12 of greater diameter, which is also axial and is intended to supply hot air coming from an external installation, the circuit of the air being able to be opened or closed by a possible dehumidification system for the heat recovery. The rotor inside the casing 1 comprises a central, that is intermediate, structure which forms a manifold 14 for the circuit of the air coming from the axial duct 12 and which receives the end of duct 9 with the radial branches 16 of said duct which makes part of the liquid circuit. The discoidal structure making up the manifold 14 is a supporting structure from the opposite side of which a plurality of hollow arms, generally indicated by 18, develop through a substantially triangular development in the section having slightly concave walls developing from the vertexes defined by the tubular structures 18A, 18B, one of which, at least ― especially the internal one indicated by 18A ― is perforated to give rise to jets of liquid fed through the relevant radial connections 16. The arms 18 are closed at their outer ends by walls 20 which extend beyond the section of the individual arms to make up diaphragms for retaining the hanks engaged onto the arms. The hanks M have a development greater than the perimeter of the substantially triangular cross-section of the individual arms 18 and result retained by the diaphragms against their falling out sideways, in the manner stated above. The hanks, during the rotor rotation, tend at each revolution to slightly advance in a rotational manner on the respective arm owing to the fact that, since they are longer than the perimeter thereof, they are moved, at each revolution, to a limited extent with respect to the hank support on the tubular structure 18A, 18B, 18B and, therefore, some motion of the hanks on the arms and thus a uniformity of the dyeing of same hanks during the process of dyeing liquid circulation are obtained. The hanks can be easily inserted onto the arms and withdrawn therefrom through easy operations that may be carried out manually or by means of a substantial automation, both upon the cumulative transfer of several hanks and by the replacement of members located inside the casing 1 and making part of the rotor. The arms 18 having perforated walls allow, by the supply of hot air from the axial duct 12 through the manifold 14, the hanks mounted on the rotor to be invested by hot air and the drying thereof to be determined by an open or closed circuit as above indicated. The liquid jets that can be generated by the nozzles of the tubular structures 18A, fed by radial ducts 16 and duct 9, invest the hanks mounted on the arms with a substantial uniformity, the jets being inwardly directed to the tubular structures 18A and possibly also in a direction other than the radial centripetal direction with respect to the rotor axis. During the operation, after having loaded the hanks M on the rotor, this is driven into a relatively slow rotation and the liquid circuit 3, 5, 7, 9, 16, 18A is activated, thereby the liquid, that may be a washing and/or a dyeing liquid and, successively, a washing liquid or another suitable one according to the textile material to be treated, provides a uniform treatment of the hanks during a cycle in which the rotor is made to rotate relatively slow in order to allow a uniform treatment of all hanks and every hank along their development. The treatment is carried out through a close cycle of the liquid which is collected on the bottom 1A of the tank and in the sump 3, for a repetition of circulation, or even through an open cycle for the washing, for example. Once the treatment of the liquid which is practically a treatment in a short bath, is completed, the drying of the hanks of textile material is carried out directly in the same apparatus. To achieve this, the centrifugation at a high speed of the rotor is firstly caused after the interruption of the liquid circulation; soon after ― (or even during the centrifugation and following the same centrifugation) ― and through a slowing down of the rotor, a drying is caused by forced circulation of hot air coming from the axial duct 12 and thus from an external installation, and which is distributed through the manifold 14 within the hollow arms 18 of the rotor, to be discharged from the perforations of the walls of same arms, thereby effectively investing the hanks mounted on the rotor arms. The drying also takes place uniformly because of the effect of the rotor rotation and thus of the periodic advancement of the hanks on the respective arms, thereby also the drying treatment takes place uniformly for all the hanks and for all the points of the hanks. The hot air circulation may be performed through an open cycle with outside discharge or through a closed cycle with recovery and possible dehumidification of the air being recycled. The dyeing and drying treatment cycles are very fast and do not imply a manual intervention between one operation and the other, since the operations are carried out in the same casing 1. Fig.3 shows a modified embodiment with respect to the one shown in Figs.1 and 2. Numeral 41 indicates a casing whose bottom 41A forms a sump 43 wherein a pump 45 for the liquid is located, able to supply it, through a delivery duct 47, to an axial duct 49 making part of the rotor inside the casing. The rotor is completed by an axial part 52 and is developed with a discoidal central structure 54, forming a manifold for the liquid coming from the axial duct 49. The manifold 54 supports arms 58, similar to those indicated by 18, which develop parallel to the axis of the rotor from opposite sides of the discoidal structure of manifold 54. The arms 58 are also hollow with perforated walls, and exhibit tubular structures like those indicated by 58A forming nozzles which are, on the average, turned in centripetal direction, similarly to the structure 18A of the preceding example, and also exhibit outer diaphragms 60 for the retention of hanks M. The central discoidal structure formed by the liquid-collecting manifold 54 extends to the outside of the crown of arms 58 to make up a part 54A forming an annular manifold for the air circuit, so as to supply hot air from the outside into the arms 58 and thus through the holes of the walls of same arms. This manifold-like part 54A is surrounded by a stationary manifold 64 which has a substantially annular development and a cross-section that may progressively decrease starting from a supply zone and that has inwardly, that is, centripetally directed passages, which match perfectly to corresponding passages, peripherically, developed and outwardly directed on the air-collecting manifold part 54A. As a consequence, the hot air generated by an external installation and pushed into the manifold 64 enters the manifold 54A of the rotor to reach the cavities of arms 58 and be blown through the perforated walls of said arms on the material of hanks M fitted on said arms. A drying effect owing to a hot air circuit is thus obtained similarly to what has been achieved according to the previous example. A further example of embodiment is shown in Figs.4 and 5, wherein the realization of the circuit of air is similar to that of the example in Figs.1 and 2, while the liquid circuit is modified. A casing or case 71 is provided for the whole dyeing and drying treatment; the casing comprises a bottom 71A having sumps 73 for two pumps 75 for the liquid circulation. Numeral 77 indicates the delivery and lifting ducts of pumps 75 which give rise to two splits that is separated circuits for the liquid. These delivery ducts lift the liquid up to two sets of supply ducts 79 and 81 developed at two different levels, which supply the liquid to respective overflowing tanks 83 and 85, each of which has an overflowing edge for producing a curtain of falling liquid indicated by C. The casing 71 contains a rotor having an axial duct 89, a manifold with radial passages 91 and perforated arms 93, so as to invest the yarn of hanks M being mounted on the arms 93. The arms 93 may have a substantially triangular development in their cross-section and a perimeter lower than the annular development of the hanks; the hanks are retained by external diaphragms 95 which prevent them from coming out of the arms during rotation. The upper tanks 85, with the relevant supply ducts 81, are so disposed as to result above the upper part of rotor 89, 91, 93; the overflowing tanks 83, at the lower level with the relevant supply ducts 79, are so disposed as to result mid-way located in the space between the central rotor core, represented by the axial duct 89, and the arms 93, so that the overflowing tanks 83 result above the arms 93 which instantaneously cover the lower length of their circular trajectory during the rotor rotation. From the above disposition it follows that during the rotor rotation the hanks fitted on the arms 93 interfere with the liquid curtains C which are formed by the overflowing edges of tanks 85 and 83 respectively along the upper trajectory and along the lower trajectory of the hanks during the rotation of same rotor. The hanks having greater dimensions than the arms diameter on each revolution, besides rotating about the rotor axis, tend to rotatively advance by small stretches or steps at every revolution but always in such conditions as to modify their support arrangement with respect to arms 93. Consequently, all the yarn material of hanks is uniformly interested by the falling liquid of curtains C, and a perfectly uniform treatment of the loaded material is thus achieved in all the hanks and throughout the development of each hank. The treatment cycle provides a first treatment with the described liquid circuit and this treatment may be a single dyeing treatment as well as other successive washing, dyeing, cooling and other treatments too, according to the material being treated. On the completion of the treatment with the liquid, in order to achieve the drying of the hanks of textile material, this is subjected to a centrifugation with a relatively marked increase of the rotor rotation speed which, during the liquid-based treatment, is relatively slow; after the centrifugation treatment, or even during a portion of the centrifugation treatment, a drying treatment is carried out by hot air evaporation through the admission of hot air into the axial duct 89 and the discharge of said air through the perforations of the walls of arms 93, in order to make same air invest the textile material hanks mounted on arms 93. The apparatus may be manually loaded through side doors, but a substantial automated loading of the hanks may also be provided, either by a simultaneous transfer of a plurality of hanks onto or from the arms, or by a partial replacement of the rotor structure to replace the hanks with greater rapidity. It is understood that the drawing shows an exemplification given only as a practical demonstration of the invention, as this may vary in the forms and dispositions without nevertheless departing from the scope of the idea on which the same invention is based.

Claims: 1. Apparatus for dyeing of yarn hanks in a short bath and the drying thereof, comprising a casing (1) for delimiting the space for the dyeing and drying, a circuit (5, 7, 9, 16, 18A) for the circulation of liquid from the bottom of said casing to make same liquid invest the yarn of the hanks, and a rotor (9, 12, 16) rotating about a horizontal axis, said rotor comprising means (18) for supporting the yarn hanks, characterized in that said rotor (9, 12, 16) is provided with a central manifold (14) supporting hollow arms (18) disposed about the rotation axis of the rotor and which project from opposite sides of the rotor, are shaped to support hanks of yarn and present perforated walls; that a circuit (12, 14, 18) of air under forced circulation is provided, supplying said manifold (14) and causing discharge of air from the perforated walls of said arms (18) to make said air invest the yarn hanks fitted on and supported by said hollow arms (18), and that program means are provided to put in action the slow rotation of the rotor (9, 12, 16) and the liquid circuit, then the fast rotation of the rotor for centrifugation and, afterwards, the slow rotation of the rotor and the air circuit to complete the drying. 2. Apparatus according to claim 1, characterized in that said air circuit (12, 14, 18) comprises a duct (12) coaxial with the rotor (9, 12, 16), supplied from the outside and leading into the manifold (14). 3. Apparatus according to claim 1, characterized in that said air circuit comprises an annular, stationary manifold (64) surrounding the rotor manifold (54A) and passages which correspond to one another in said two manifolds for feeding the rotor manifold (54A) in a centripetal direction. 4. Apparatus according to claims 1 or 2 or 3, characterized in that the circuit for the liquid circulation comprises a duct (9; 49) coaxial with the rotor (9, 12, 16; 49, 52, 54) which supplies ducts (18A; 58A) on the rotor being provided with nozzles to invest the yarn hanks. 5. Apparatus according to claims 1 or 2 or 3, characterized in that the circuit (75, 77, 79, 81) for the liquid circulation comprises stationary overflowing tanks (83, 85) generating curtains (C) of falling liquid which are intercepted by the hanks (M) kept in motion by the rotor. 6. Apparatus according to claim 5, characterized in that said overflowing tanks (83, 85) are disposed at a level higher than the rotor (89, 91, 93) and at an intermediate level with respect to the rotor, between the horizontally projecting arms (93).

Inventors: RIGACCI, FERNANDO
Applicants: TESSILBREVETTI S.R.L.
Application year: 1988
Main classification: D06B5
IPC codes: D06B5