EP0182297A2 - Process and device for drying textile materials - Google Patents

Abstract

Process and device for drying textile materials in the form of yarn spools, a first drying stage being carried out by throughflow drying and a second drying stage by HF drying. In this connection, the HF drying takes place as "radial" drying by means of an HF field which penetrates the spools radially from inside to outside. The HF drying is in this connection to be carried out subsequent to the throughflow drying, without the yarn spools being separated beforehand, thus preserving their arrangement on the textile material support used for the throughflow drying, which is as a unit, if at all necessary, transferred into another textile material container. <IMAGE>

Description

The invention relates to a method for drying textile material in the form of yarn spools or also reel-winding, and an associated device according to the preamble of claim 3.

After the wet treatment of a textile good, it is absolutely necessary to dry it again. There are several different procedures for this.

One of these procedures consists of through-flow drying, which can be carried out both as so-called rapid drying and as so-called pressure drying. It is essential for both types of through-flow drying that a possibly heated and possibly even very strongly heated gas stream is passed through the textile material.

Flow drying is known for example from DE-PS 9 70 012; however, it is also described in GB-PS 12 19 855, in DE-AS 21 09 696 and in Textile Finishing 1978 pages 367 to 372. Finally, however, it is also discussed in detail in Textile Practice 1964, pages 386 to 394 and 501 to 506. As is well known from this and the rest of the matter, wet-to-treat spools of thread are first placed on suitable carrier devices, namely so-called bobbin carriers or the like, in a plugged-on form, together with the carrier device, introduced into a wet treatment apparatus in order, for example, to be dyed there. after which the carrier device together with the coils are removed from the wet treatment apparatus and inserted into a flow-through dryer, where the flow-through drying process takes place. The transfer of the carrier device from the wet treatment apparatus into the through-flow dryer does not otherwise require the individual coils to be separated or otherwise reloaded, which is why the handling associated with through-flow drying can be assessed as extremely favorable due to the short set-up times. On the other hand, through-flow drying is disadvantageous because the uniformity of the degree of drying that can be achieved depends to a very large extent on the uniformity of the winding or other density of the textile material. Since even with the most modern winding machines, differences in the winding density of 3% cannot be avoided, there is also a corresponding unevenness in the residual moisture in the windings during the through-flow drying; unless the wraps are initially completely over-dried in a manner which is very disadvantageous for the textile goods, i.e. to well beyond the hygroscopic balance.

Another method of drying textile goods that has also been known for a long time is HF drying. For HF drying of bobbins and the like, these are after the preceding wet treatment was always first removed from the carrier device and used individually for mechanical pre-dewatering in a centrifuge. After centrifuging, the bobbins of thread have again been placed individually on a conveyor belt which has passed them through an HF field. The HF field was located in a tunnel-like facility, which made it possible to extract the moisture released during HF drying by means of a gas stream. The handling of HF drying just described is very labor intensive in contrast to handling for through-flow drying. On the other hand, HF drying is also associated with a not inconsiderable consumption of electrical energy if the entire moisture contained in the textile goods is to be dried off after a wet treatment. However, HF drying is far superior to through-flow drying in terms of the end result, since the uniformity of the residual moisture does not depend in any way on the uniformity of the winding density; Even almost extremely different winding densities can be used to achieve a consistently uniform, always reproducible and otherwise precisely adjustable residual moisture by means of HF drying. These and other details of HF drying are known, for example, from Melliand Textile Reports 1982 pages 667 to 672, from Textile Company 1982, pages 56 to 58 and from textile practice international 1976, pages 1416 to 1418 and 1978, pages 64 to 66 and 165 to 167 .

The uniformity of the residual moisture remaining after a drying process in a yarn package or the like is an almost indispensable prerequisite for trouble-free further processing of the textile goods.

The invention is therefore based on the object of demonstrating ways and means which make it possible to get by with the favorable handling of through-flow drying and yet the excellent uniformity of the residual moisture of the HF drying to reach. To achieve this object, the invention provides for the drying process to be carried out in two stages.

To solve this problem in terms of process technology, reference is made to the details of claim 1. According to the definition of the method according to the invention there, the first stage consists of through-flow drying and the second stage consists of HF drying, the latter also having to be carried out in a special new form, namely as "radial" HF drying. The further drying, namely the HF drying, is usefully carried out until the hygroscopic equilibrium is reached, which is the ideal case for the further processing of the textile goods. An essential feature of this procedure according to the invention is that between the through-flow drying and the HF drying, the textile material no longer has to be repacked, in order to be done by HF drying as before, in the form of individual spools of thread on a conveyor belt by an HF -Train drying tunnel. After the through-flow drying, the textile material can be subjected to the HF drying without changing the package shape as a whole, without having to use excessively high electrical energies for the HF drying. On the one hand, this is due to the fact that most of the moisture is already removed in the course of the first drying stage, namely through-flow drying, which is associated with extremely favorable handling, and without paying attention to achieving uniformity of drying at all should be. Any non-uniformities in the through-flow drying are completely equalized in the subsequent HF drying, even if the winding density is uneven. On the other hand, the HF drying can be carried out without using excessively high electrical energies, because it is carried out as a "radial" HF drying and in this the HF field only has to penetrate the thickness of the yarn packages.

Overall, the method according to the invention thus actually achieves drying uniformity, as was previously only possible with overdrying and subsequent long-term storage. In addition, this favorable result is also achieved in conjunction with very cheap handling, which was previously not possible. Finally, it should be noted that the favorable result without any impairment of the strength and all other special properties of the yarns, which was not the case with overdrying previously carried out to achieve uniform moisture, and without the use of excessively strong HF fields is achieved.

The through-flow drying should expediently be carried out to such an extent that a moisture of essentially 15% can subsequently be determined in the textile material, which can be reduced to the desired final value by means of HF drying.

In terms of device technology, the object on which the invention is based is achieved by the measures specified in claim 3.

First of all, the starting point is a textile goods container of the type previously used for through-flow drying. The first part of the drying process according to the invention, namely through-flow drying, is carried out in this textile goods container. For the further drying, namely the HF drying, a textile goods container is also provided, which, however, is designed with regard to the special drying, namely for this purpose in particular HF electrodes and the possibility of suctioning off the moisture released by the HF drying. So that the coil carriers, which are to be used in the textile goods container used for through-flow drying, can also be used unchanged for HF drying, the HF electrodes must be turned on number ago to be matched to the number of coil columns of the coil carrier; this coordination naturally also affects the geometrical arrangement of the HF electrodes.

For the device according to the invention in its entirety, there is the possibility that the textile goods container used for HF drying is identical to the container provided for through-flow drying, provided, however, that the only textile material container then has the HF electrodes in an appropriate number and arrangement. Of course, on the other hand, there is the possibility of providing a separate textile goods container for HF drying, so that a total of two textile goods containers are provided, which are coordinated with one another to such an extent that only the bobbin is removed from the textile material container used for through-flow drying and into those of the HF drying serving textile goods container must be used.

On the other hand, there is of course also the possibility of providing two textile goods containers and forming each of them in such a way that the through-flow drying and the HF drying can of course be carried out one after the other. In this case, in an expedient further development, of course, only one set of units for through-flow drying and one set of units for HF drying are required if corresponding switchover devices are provided which make it possible for one of the two containers to work in one way, while at the same time each other container works in the other way.

Further details of the method according to the invention can be seen from the following detailed description of an embodiment of the device according to the invention for carrying out the method, which refers to the associated drawings.

• Figur 1 einen schematischen Längsschnitt durch einen sowohl zur Durchströmungstrocknung als auch zur HF-Trocknung ausgebildeten Textilgutbehälter und
• Figur 2 einen schematischen Längsschnitt durch einen ausschließlich zur HF-Trocknung ausgebildeten Textilgutbehälter.

In these show:

• Figure 1 is a schematic longitudinal section through a both Textile containers designed for flow drying as well as HF drying
• FIG. 2 shows a schematic longitudinal section through a textile goods container designed exclusively for HF drying.

A conventionally designed textile goods container 1 is placed on a foundation 2 or the like. This textile goods container 1 is expediently a pressure-resistant container and closed at the top by means of a lid 3, which is either completely removable or can at least be opened so far that the interior of the textile goods container 1 is fully accessible. At the bottom 4 of the textile goods container 1, a connection 5 is provided for supplying a gas stream. A corresponding discharge connection 6 is provided relatively high on the textile goods container 1. From the supply connection 5 extends into the interior of the textile goods container 1 and up to a little above the inner bottom region of the textile goods container 1, a standpipe 7, the interior of which serves to continue the supplied gas flow and which also serves as a receiving bearing for the textile goods carrier, which in the exemplary embodiment here as Coil carrier 8 is formed.

The coil support 8 consists essentially of a hollow column body 9, which is continued at one end in a hollow plate 10 and which is inserted with its free lower end into the upper inner end of the standpipe 7.

So-called coil columns 11 extend downward from the underside of the plate 10. The coil columns 11 are formed by perforated sheet metal "cans" 12 welded to the underside of the plate 10.

To equip the coil column cans 12 with, for example, winding coils 13, the coil carrier 8 is removed from the textile goods container 1 and its plate 10 is loaded onto one the other document. Then a centrally perforated plate 14 made of electrically non-conductive material is inserted into the interior of the cans 12 and communicates with the cavity of the plate 10 via its opening 15. Then the winding coils 13 are inserted into the interior of the cans 12, the winding or coil cores 16 of which are broken. Finally, the cans 12 are closed at their free end by means of a further centrally perforated plate 17 made of electrically non-conductive material to prevent the winding coils 13 from falling out.

The bobbin 8 equipped in this way is then inserted into the textile goods container 1.

During the throughflow drying, the gas supplied via the supply connection 5 reaches the interior enclosed by the winding cores 16 and from there through the textile material through the perforated cans 12 into the interior of the textile material container 1 and from there via the discharge connection 6 to the outside again. Outside the textile goods container 1, the feed connection 5 and the discharge connection 6 can be connected to one another via a circulation line, not shown, into which a pump for circulation purposes, a heater and a water separator should be installed.

Of course, there is also the possibility of through-flow drying in a non-closed mode of operation, i. H. the supply connection 5 and the discharge connection 6 are not connected to one another, one of the two being assigned a pressure or suction pump and expediently a heater is also connected upstream of the supply connection 5.

With regard to carrying out the HF drying, 1 HF electrodes 18 are provided in the interior of the textile goods container, which are connected to one another via connecting plates 19 and are, in principle, insulated from the container base 4. At least one of the connecting plates 19 is expediently guided through the housing base 4 to the outside, in a sealed manner, and is connected to an HF generator 20, which on the other hand is connected to the textile goods container 1.

The RF electrodes 18 are arranged in a number corresponding to the number of coil columns 11 in the container 1, at the same time corresponding to the spatial arrangement of the coil columns 11. This means that the HF electrodes 18 are always inserted into the cavity enclosed by the perforated sleeves 16. For HF drying of the textile material, the HF generator 20 is switched on after switching off the auxiliary units belonging to the throughflow drying, and the connection 6, which was originally used for removal purposes, and the other connection 5 originally used for supplying purposes, are connected to a device for suction, not shown, so that the moisture released by means of HF drying can be removed from the inside of the textile goods container.

The above description of the structure of the device of FIG. 1 has at the same time sufficiently clarified the process for drying textile material firstly by flow drying and then by HF drying, with the latter part of the drying being noted that due to the arrangement of the HF Electrodes 18 inside the winding cores 16 and the arrangement of the cans 12 on the outside of the winding coils 13, the HF field radially penetrating the latter also a considerably shorter distance compared to the width of the winding coils 13 or the height of the coil columns 11.

The device shown in Figure 2 differs from the device shown in Figure 1 actually only in that in the device according to Figure 1 with 5 be drawn connection for the supply of gas for flow drying in the case of Figure 2 is a connection for the supply of gas as a carrier medium for the moisture released in the HF drying. This means that the textile goods container 1 according to FIG. 2, in the embodiment evident from there, is a textile goods container which serves only for HF drying.

In order to be able to carry out the process of drying textile goods according to the invention first by flow drying and then by HF drying by means of the device shown in FIG. 2, a textile goods container serving exclusively flow drying is also required. This can then be designed, for example, in accordance with the textile goods container of FIG. 1, when the HF electrodes 18, the connecting plates 19 and the HF generator 20 are removed.

As is easy to see, there is definitely the possibility, instead of carrying out the method according to the invention, to provide two such containers exclusively in a textile goods container according to FIG. 1, which are connected together to a unit for through-flow drying and an unit for HF drying, this connection being such should be that one of the two containers is connected to the unit for through-flow drying, while the other container is connected to the unit for HF drying. This connection option should be changeable in such a way that the container originally connected to the throughflow drying unit is subsequently connected to the HF drying unit, while the container originally connected to the latter is connected to the throughflow drying unit.

If the assembly of the bobbin 8 with winding coils 13 has been described in the context of the present description of the figures, this is not in itself the case Equipped with winding spools still wet, but to equip the spool 8 before a wet treatment of the winding spools prior to drying. Coil carriers 8, which have been removed from an upstream dyeing kettle, for example, are thus introduced into the textile goods container 1 of the device according to the invention. This implementation only requires extremely minimal and simple handling. In addition, it can be seen from the above description of the figures that the further course of the drying process is at most associated with an equally extensive and simple handling, namely in the case when the bobbin carrier 8 is removed from a textile material container serving the flow drying and into one of the HF drying serving textile goods container is to be used. If through-flow drying and HF drying take place in the same textile goods container, this intermediate handling is even completely eliminated.

The result of the drying according to the invention is independent of the device used in each case, namely the use of perhaps only a single textile goods container or maybe two successive textile goods containers, one for flow drying and the other for HF drying, always a dried textile material of extreme uniformity with regard to Residual moisture. The residual moisture can be practically any value that is to be achieved, including the hygroscopic balance.

Both in the device of FIG. 1 and in that of FIG. 2, the electrodes 18 are shown as hollow electrodes, the upper ends of which are open, so as to enable a fluidic connection to the hollow interior of the plate 10. Alternatively, the electrodes 18 can also be designed as solid rod electrodes, the outer diameter of which, however, must then be matched to the inner diameter of the winding cores 16 in such a way that an annular gap remains free which is in communication with the hollow interior of the plate 10.

If gas as the flow medium has been mentioned above, air is of course also to be understood as a particularly expedient, because inexpensive flow medium.

Claims (11)

1.Process for drying textile goods in the form of yarn packages, for which purpose the textile goods are first introduced into a container and then a possibly heated gas stream is introduced into the textile goods container, passed through the textile goods and discharged again from the textile goods container, the gas stream possibly also in a closed circuit can be passed through the textile goods container and the textile goods and thereby passes through a water separator located behind the textile goods container and possibly a gas heater located in front of the textile goods container, characterized in that the through-flow drying of the textile goods by means of the gas stream passed through them only until a still is reached moisture lying clearly below the desired final residual moisture of the textile goods is carried out, which is followed by further drying of the textile goods in the packing form present from the flow drying, whereby this e Further drying until the desired final residual moisture is reached, in particular until the hygroscopic equilibrium is reached, is carried out by means of HF drying and this HF drying is carried out by means of an HF field which passes through the yarn spools from the inside out or, if applicable, in the opposite direction. 2. The method according to claim 1, characterized in that the through-flow drying is carried out up to a humidity of 15%. 3. Device for drying textile goods in the form of yarn spools, in particular for performing the method according to claim 1, consisting of a particular ver closable textile goods container with connections for supplying and discharging a gas stream, from a textile goods carrier that can be inserted into the textile goods container with at least one coil column and from a pressure or suction pump for transporting the gas, and optionally from a heater arranged in front of the textile goods container for the gas and in the case of Circulation of the gas stream further comprising a circulation line connecting the inlet and outlet connections of the textile goods container and a water separator used therein, characterized by a textile goods container (1) with a number of HF corresponding to the number of coil columns (11) of the textile goods carrier (8) -Electrodes (18) which are arranged in the textile goods container (1) in such a way that the textile goods carrier (8) with its coil columns (11) can be placed on the HF electrodes (18) by means of one hand on the HF electrodes (18) and on the other hand HF generator (20.) connected to the textile goods container (1) ) and through at least one connection (6) of the textile goods container (1) for extracting the moisture of the textile goods released during HF drying out of the textile goods container (1). 4. The device according to claim 3, characterized in that the HF drying textile goods container (1) has two connections (5, 6) which are mutually used for suction of the moisture released during HF drying of the textile goods and the supply of for Serve absorption of the gas required for moisture, one connection (6) leading directly into the interior of the textile goods container (1) and the other connection (5) communicating with the hollow interior of the textile goods carrier (8). 5. The device according to claim 3, characterized in that the RF electrodes are designed as tubular electrodes (18) with openings in their walls and a free open end. 6. The device according to claim 3, characterized in that the HF electrodes (18) are designed as solid rod electrodes, the outer diameter of which is matched to the inner diameter of the coil cores (16) in such a way that an annular gap remains free. 7. The device according to claim 4 and 5, characterized in that the one connection (6) via the hollow interior of the textile goods carrier (8) is connected to the hollow interior of the RF electrodes (18). 8. Apparatus according to claim 4 and 6, characterized in that the one connection is connected via the hollow interior of the textile goods carrier (8) to the annular gap space surrounding the HF electrode (18). 9. Device according to one of claims 3 to 8, characterized in that the HF drying textile goods container and the flow drying textile goods container are formed by one and the same container (1), which alternately to the external units for flow drying and those can be connected for HF drying. 10. The device according to claim 9, characterized in that two each of the HF drying and flow drying textile goods container are provided, which are mutually connectable to the HF drying units or flow drying units. 11. The device according to one of claims 3 to 8, characterized in that the HF drying textile goods container is a separate container into which the textile goods to be dried after removal from the flow drying textile goods container is to be used.

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