EP0297097A1 - Installation for the continuous processing of at least one textile yarn. - Google Patents

Abstract

A versatile installation for the continuous treatment of textile yarns, allowing at least one heat treatment and microwave drying of the yarn while it rests freely in the form of turns on a conveyor belt. This installation comprises an impregnation and spinning machine (3), a depositing head (4) forming turns of threads on a conveyor belt (5), a heat treatment and drying chamber (7) equipped with generators. high frequency or microwave (42), a pressure vaporization chamber (8) and a yarn rewinding device (10, 11). In a part of the enclosure (7), a microwave-permeable tubular sheath surrounds the strip and the wire to maintain a warm and humid atmosphere therein. The yarns are subjected to forced ventilation during drying. By the combined use of all or part of its components, the installation allows various combinations of the following treatments: washing, dyeing, spinning, drying, fixing.

Description

 INSTALLATION FOR THE CONTINUOUS TREATMENT OF AT LEAST ONE TEXTILE YARN

The present invention relates to a DOUT installation for the continuous treatment of at least one textile thread, comprising means for continuously training at least one thread taken from a spool, a removal head for depositing this thread on a permeable conveyor belt. gas, at least one heat treatment enclosure traversed by the wire resting freely on said conveyor belt, and a device for taking up the yarn on the conveyor belt to rewind it, said thermal treatment enclosure comprising a device for drying the yarn by microwave or high frequency treatment, provided with means of forced ventilation through the wire deposit and the conveyor belt.

The use of heating by dielectric loss for the heat treatment of textile threads and in particular for their drying makes it possible to reach evaporation rates which cannot be obtained by conventional means. Indeed, it heats all the water absorbed in the various parts of the volume of the material at the same time, which produces excellent uniformity of treatment and a short drying time of a material presented in the form of a mass of relatively dense yarn. This method of drying wires is currently used in high frequency driers (of the order of 15 to 35 MHz) in which the wires are not introduced in the form of coils. However, as the usual coils have a low permeability to the passage of steam, the vaporized water has difficulty in evacuating and rises in pressure and in temperature, heating the material itself. The more the material heats up, the more its dielectric loss factor increases and it therefore absorbs even more energy. In this way a thermal runaway regime is reached, unlike the usual phenomenon of self-regulation which results from the decrease in the loss factor as a result of the progressive decrease in humidity. This thermal runaway can lead to local melting or carbonization of the wire. It is very difficult to remedy this, except by reducing the power and producing coils of specially low density. A solution to this problem is proposed in patent application GB-A-1,583,953. It is an installation in which a continuous textile support, such as a fabric or a group of parallel threads, continuously scrolls in a chamber for fixing a print. In this room, the support is subjected at the same time to a heating by microwaves and to a ventilation which crosses it. The combination of a relatively thin deposit of the wires on the conveyor belt with heating by dielectric loss makes it possible to ensure adequate forced ventilation through the deposit of wires and to eliminate the risk of thermal runaway, also thanks to the fact that the density of the wire deposit can be about ten times less than that of the coils. This takes advantage of the self-regulating drying characteristic of this heating principle and a uniform humidity of the yarn is obtained at the outlet, which can be adjusted optimally for a normal recovery rate. However, the proposed device produces rapid drying during the heat treatment, which does not allow a heat treatment to be carried out in which the textile product must be kept for a certain period in an atmosphere that is both hot and humid.

The object of the present invention is to remedy this drawback, thanks to a multi-purpose installation operating continuously.

For this purpose, the invention relates to an installation of the type indicated in the preamble, characterized in that said heat treatment enclosure comprises a fixing zone, provided with a tubular sheath surrounding the conveyor belt and the wire deposited thereon, this sheath having a double wall made of material permeable to the high frequencies or microwaves used and enclosing in this double wall a heating fluid circuit, and a drying zone situated downstream of the fixing zone, the assembly constituted by the zone fixing and drying area being equipped with high frequency or microwave generators.

The depositing head is preferably a head depositing the wire in the form of turns or according to another repetitive geometry. In conventional high-frequency dryers, the water load at the inlet and outlet of the HF applicator is variable depending on the type of material to be treated (cotton, wool, polyester, etc.) and an automatic correction at each batch change is complicated and above all represents a big investment. On the contrary, in an installation according to the invention, the water load can easily be adjusted by varying the speed of removal and transport as a function of the title and the quality of the wire. As a result, the obligation to rigorously control the conditions for adapting the impedance of the HF applicator is eliminated.

As this device allows the use of a deposit of wires under a relatively small thickness, for example not exceeding 40 mm, it is possible to carry out drying by means of microwaves whose frequency is of the order at 2,450 MHz. In fact, the penetration depth being inversely proportional to the frequency and to the losses, such high frequencies cannot be used to heat coils of current size.

Preferably, the heat treatment enclosure has at least one air inlet located above the conveyor belt, at least one air outlet located below this conveyor belt and connected to suction means, and deflectors. arranged between the edges of the strip and the respective side walls of the enclosure so as to force the air to pass through the strip.

In addition to the aforementioned elements and in order to allow the use of said elements in different treatment methods, the installation according to the invention can be supplemented by various treatment units arranged upstream or downstream of the enclosure. heat treatment. In particular, it may comprise at least one wringing device arranged on the path of the wire upstream of the depositing head, this wringing device preferably being of the pneumatic expressing type. The installation may also include at least one means for impregnating the wire upstream of the wringing device. In a preferred embodiment, the installation comprises, upstream of the deposition head, an impregnation machine in which are grouped the impregnation means and said wringing device. This impregnation machine may include a tank containing a liquid bath through which the course of the thread extends, for example for washing or dyeing the thread. The installation may further include a pressurized steam thermofixing chamber, crossed by the conveyor belt between the heat treatment enclosure and the wire take-up device.

According to another aspect resulting from the principles set out above, the present invention also relates to a continuous drying process of textile threads resting freely on a conveyor belt permeable to gases, in which said strip supporting the threads is made to flow through a enclosure being substantially at atmospheric pressure, the wires are exposed to microwaves causing the water contained in the wires to heat up, and forced ventilation is simultaneously carried out through the wires and the trans¬ carrier, characterized in that, in an initial zone of the path of the conveyor belt in said enclosure, the forced ventilation is locally suppressed and a high humidity level is maintained around the wires by means of a heated sheath permeable to microwave, surrounding the strip and the wires supported by it.

The present invention and its advantages will be better understood with the aid of the description of a preferred embodiment of the installation, given below by way of example and with reference to the appended drawings, in which:

FIG. 1 is a schematic side view, partially cut away, of an installation comprising in particular an impregnation machine and a heat treatment enclosure,

FIG. 2 is a schematic view in longitudinal section of the impregnation machine,

FIG. 3 is a diagrammatic view in longitudinal section of the heat treatment enclosure, and Figure 4 is a schematic cross-sectional view along line IV-IV of FIG. 3.

The installation shown globally and diagrammatically in FIG. 1 is a line for processing one or more textile yarns 1 (in the description which follows, we will generally speak of a single yarn to simplify the description). The installation consists of a series of units which are traversed by the wire being processed and which include: a reel rack 2 from which the wire is taken continuously; an impregnation machine 3, the various functions of which will be specified below and in which the wire circulates in its longitudinal direction; a depositing head 4 having the function of depositing the wire 1 on a conveyor belt 5 according to a determined geometry, for example in the form of turns 6 which are laid backwards by resting on each other in staggered fashion; a heat treatment enclosure 7, crossed by the carrier strip 5; a heat-setting chamber 8, also traversed by the conveyor belt 5; a drive mechanism 9 for the conveyor belt 5; and a device 10 for picking up the thread on the conveyor belt, for rewinding it on a winding machine 11. Although they have not been shown, the installation naturally includes supply members supplying the various fluids necessary for processing. , as well as control units which coordinate the operation of the various units.

In this installation, the units 2, 4, 8, 9, 10 and 11 are well known and do not require any particular description here. Similarly, the conveyor belt 5, which is perforated so that it can be traversed in particular by air and water vapor, is part of a conveyor of the type commonly used in the textile industry.

We will refer to fig. 2 for the description of the impregnation machine 3. Along the path of the wire 1, this machine successively comprises in a first stage 12 a separation comb 13a for the case where several wires are treated in parallel , a brake 13b used in the event of a stop, pulleys 14 for driving the wire 1, a washing or dyeing tank 15 containing a bath 16 through which flows the wire, and a wringing device 17 disposed at the outlet of the tank 15.

The wire 1 is then driven by another set of pulleys 18 to a second stage 20 which essentially comprises three similar modules 22 arranged in series on the path of the wire. Each module 22 is intended to spin and possibly impregnate the wire beforehand. For this purpose, it comprises an enclosure 23 provided with an inlet and an outlet for the wire 1, as well as a liquid recovery tank 24. This enclosure contains an impregnation device 26 and a device for spin 27, of the pneumatic expressing type, which is shown in longitudinal section in detail A of FIG. 2. Note that this device is of a particularly simple construction; it is formed by a housing, two opposite walls 28 and 29 of which are each pierced with an orifice 30, 31 for the passage of the wire. These orifices have a flared shape at the inlet and at the outlet and each have a minimum diameter which is slightly greater than that of the wire. To produce the spin, compressed air is introduced along arrow B into a central duct 32 communicating with the orifices 30 and 31- The air escaping at high speed and with a strong pressure drop around the wire in the two orifices carries a large part of the liquid contained in the wire, which is collected in the tank 24. If it is not desired to carry out a spin, it suffices to stop the supply of compressed air, the wire can then continue to flow through the device.

The impregnation device 26 is constructed in a similar manner to the device 27. Instead of injecting compressed air, the arrow B is injected with dye liquid or any other treatment liquid with which it is desired to impregnate thread. This can then be spun directly in the same module 22 or only in one of the following modules.

It should be noted that, if the first stage 12 of the impregnation machine 3 is not used, the wire can be passed directly from the reel rack 2 to the second stage 20, following the shortened path 1 'shown in broken lines in fig. 1. The general shape of the heat treatment enclosure 7 is shown schematically in FIGS. 3 and 4. Along the path of the conveyor belt 5 supporting the turns of wire 6, this enclosure comprises: an entrance corridor 34 fitted with metalli¬ cal valves 35 serving as wave traps; a fixing chamber 36 in which the conveyor belt and the turns of wires are surrounded by a tubular sheath 37; a drying chamber 38 which communicates with the fixing chamber 36 through an opening 39; and an outlet corridor 40 fitted with metal valves 35. A series of microwave generators 42 is distributed along the upper wall of the two chambers 36 and 38 so as to expose the turns of wire 6 to the microwaves. microwaves are confined inside the enclosure 7 by the metal walls of the enclosure and by the metallic valves 35. The preferred frequency for heating the water contained in the wire is 2,450 MHz. In a prototype installation, forty 1.2 K generators are planned.

The sheath 37 is partially open at both ends and essentially comprises a double-walled tube made of material permeable to microwaves, for example glass. In the annular space delimited by the double wall, steam is introduced, introduced according to arrow C and discharged according to arrow D, to heat the sheath 37. As this sheath tightly surrounds the conveyor belt 5 and the turns of wire, the wire is exposed in this sheath to a particularly hot and humid microcli¬ mat. Indeed, on the one hand the wire is not ventilated in this area while being heated by the microwaves, and on the other hand the moisture escaping from the wire cannot condense on the heated walls of the sheath 3, so that the atmosphere remains extremely humid in this sheath. In this way, the moisture-laden wire undergoes a uniform heating up to a temperature of the order of 80 to 100 ° C., favorable for example for fixing a dye on the fibers.

The two chambers 36 and 38 are ventilated by air introduced at the top of the enclosure, as shown by the arrows in FIG. 4, through the microwave generators 42 in order to cool them. The moisture-laden air is evacuated from the fixing chamber 36 by a suction duct 43 - In the drying chamber 38, the air introduced from above is forced to pass through the wire deposit 6 and the conveyor belt 5, thanks to deflectors 44 which seal the space between the strip 5 and the side walls of the enclosure. The air is discharged downwards through a suction duct 45.

The combination of the fixing chamber 36 and the drying chamber 38 in one and the same microwave treatment enclosure 7 makes it possible to carry out a complex heat treatment with great savings from the point of view of construction, space and of energy consumption. It also allows rapid drying thanks to the significant initial heating up of the products by microwaves or high frequencies during the first part of the treatment, where the humidity is maintained at a high rate.

In an installation according to the invention, the heat-setting chamber 8 is optional. However, it is generally advantageous to integrate this room into the installation if the space available is sufficient. It can be taken out of service without affecting the functioning of the rest of the installation. Such a chamber, equipped with roller locks 48 at the entrance and at the exit, is well known in the industry and does not require any particular description.

A remarkable advantage of the installation described above is its modular design offering multiple possibilities of use, by various combinations of the following operations:

a) unwinding on the rack 2, b) impregnation in the machine 3, in the tank 15 and / or in the impregnation device 26, c) single or multiple spinning in the machine 3, d) deposit by the head 4 on the strip 5, e) drying by HF or microwave, with possible fixing, in the treatment enclosure 7, f) spraying under pressure in the chamber 8, g) winding of the dry wire on the winder 11. We indicate below some examples of treatment with the corresponding combination of operations.

- Drying of a previously wrung wire in a centrifuge: a) + d) + e) + g).

- Drying of a thread which has not been wrung beforehand: a) + c) + d) + e) + g).

- Washing and drying, for example for fat spun yarns: a) + b) + c) + d) + e) + g).

- Dyeing without fixing under pressure: a) + b) + c) + d) + e) + g).

- Dyeing with pressure fixing: a) + b) + c) + d) + e) + f) + g).

In all cases, the spin can be modulated by the use of one or more pneumatic expressing devices in the machine 3, as well as by varying the pressure of compressed air. On the other hand, by adjusting the wire drive speed, the water load at the inlet of the heat treatment chamber 7 is adjusted. By adjusting the speed of the conveyor belt 5, the density is adjusted. of the wire deposit on the strip.

Claims

claims

1. Installation for the continuous treatment of at least one tex¬ tile wire, comprising means for continuously driving at least one wire taken from a coil, a removal head (4) for depositing this wire on a permeable conveyor belt gas, at least one heat treatment chamber (7) through which the wire rests freely on said conveyor belt, and a device (10) for taking up the wire on the belt, conveyor for rewinding, said heat treatment chamber comprising a wire drying device by microwave (42) or high frequency treatment provided with means (44, 45) of forced ventilation through the wire deposit (6) and the conveyor belt (5), characterized in that said heat treatment enclosure (7) comprises a fixing zone (36), provided with a tubular sheath (37) surrounding the conveyor belt and the wire deposited thereon, this sheath having a double wall of material permeable to high frequencies or microwaves used and containing in this double wall a heating fluid circuit, and a drying zone (38) located downstream of the fixing zone, the assembly constituted by the fixing zone and the zone dryer being equipped with high frequency or microwave generators (42).

2. Installation according to claim 1, characterized in that the removal head (4) is a head depositing the wire in the form of turns or according to another repetitive geometry.

3. Installation according to claim 1 or 2, characterized in that the heat treatment enclosure (7) comprises at least one air inlet situated above the conveyor belt (5), at least one air outlet ( 43, 45) located below this strip and connected to suction means, and deflectors (44) arranged between the edges of the strip and the respective side walls of the enclosure so as to force the air to pass through the band.

4. Installation according to any one of claims 1 to 3. characterized in that it comprises at least one wringing device (17, 27) disposed on the path of the wire upstream of the removal head (4)

5. Installation according to claim 4, characterized in that said wringing device (17, 27) is of the pneumatic expression type.

6. Installation according to claim 4, characterized in that it comprises at least one means (16, 26) for impregnating the wire, disposed on the path of the wire upstream of a wringing device (17, 27) .

7. Installation according to claim 6, characterized in that it comprises upstream of the removal head (4) an impregnation machine (3) in which are grouped the impregnation means and the wiping devices.

8. Installation according to claim 7, characterized in that ^' the impregnation machine (3) comprises a tank (15) containing a liquid bath through which extends the path of the wire.

9. Installation according to claim 8, characterized in that it comprises a thermofixation chamber (8) under pressure steam, traversed by the conveyor belt between said heat treatment enclosure (7) and the wire recovery device (10).

10. A method of continuously drying textile threads freely resting on a gas-permeable conveyor belt, in which said strip carrying the threads is circulated through an enclosure being substantially at atmospheric pressure, the threads are exposed to micro- waves causing the water contained in the wires to heat up, and forced ventilation is simultaneously carried out through the wires and the conveyor belt, characterized in that, in an initial zone of the path of the conveyor belt in said enclosure, the forced ventilation is locally suppressed and a high humidity level is maintained around the wires by means of a heated sheath permeable to microwaves, surrounding the strip and the wires supported by it.