EP1609892A1 - Method and apparatus for the preparation of fibrous material - Google Patents

Abstract

Raw fibers (15) are conveyed (4) by an air steam to feed rollers (9), which place them on a rotating perforated drum (23). Hot air (30), e.g. at 170 to 190 [deg]C, is blown through the fiber from the outside to the interior of the drum to shrivel any plastic contaminants. The mixture is removed by take-off rollers (18) and conveyed (32) to separation and cleaning stages. The hot air is recycled (13). An independent claim is also included for hot air treatment equipment in which the fibers are held on their conveying support (23) purely by the difference in air pressure. The support can be a perforated drum, a perforated belt running in a curved or a straight path, or two drums in series. In an alternative construction, the fibers are also compressed locally by compression rollers. The density of the fiber layer is preferably 70 to 200 g/m2>.

Description

The invention relates to a method for thermal treatment of fiber material for the subsequent excretion of contained therein foreign substances made of plastic according to the preamble of claim 1 and an apparatus for performing the Method according to the preamble of claim 14.

Such methods and devices are described, for example, in used in the textile industry and serve in particular in the Vorwerk of a spinning mill (blowroom) Foreign matter made of plastic excrete from the raw fiber material supplied. The raw fiber material for example, relates to natural fibers, such as wool, silk or cotton. Raw fiber material is usually wrapped in or tied up bales for further processing to a Blowroom delivered. As a packaging material are in particular used thermoplastic materials. That's why it is usually unavoidable that part of the spinning delivered Fiber material is contaminated with plastics. packaging remnants on the fiber material impair their processing, i.e. in order to process such fibers into yarn must Residues of packaging materials separated from the fiber material become.

WO 00/10738 describes a device for the separation of unwanted plastic material, in particular polyethylene and Polypropylene, of natural fibers, in particular of wool, the device comprising a heat treatment device and a conveyor for transporting the fiber mixture through the heat treatment device having. The fiber mixture is here preferably as a nonwoven, so that it is transported by means of rollers can be. In the heat treatment apparatus, the fiber mixture becomes to a temperature below the melting temperature of the Plastic material heated, the plastic material, in particular Stretched thermoplastics, shrinks and embrittles. The clumped plastics can then, for example by knocking, carding, combing or simple optical recognition and eliminated from the fiber mixture.

According to WO 00/10738, the heating of the fiber mixture takes place by a heated gas, which in the heat treatment device is initiated. The heated gas becomes, for example perpendicular to the transport direction on the contaminated with foreign substances Passed fibers and then flows through them in vertical Direction. In the preparation of a present as a band Fiber mixture, this is transported between each two Transport rollers or between two in the opposite direction of rotation rotating, perforated endless belts pressed, i. the The fleece can either hang freely between two pairs of rolls or on or between two perforated endless belts lying from the heated gas to be flowed through.

WO 00/10738 also describes the thermal treatment of in flake form present fiber material, said fiber flakes at least one pair of rollers with counter-rotating, perforated, hollow cylindrical rollers pass through. in this connection the flakes are pressed together and heated at the same time, flowing through the perforated rollers flowing gas, or flows around on a heating path of heated gas.

The thermal treatment of a compressed fiber mixture in the form of flakes or in the form of a nonwoven fabric by means of a flowing hot gas is because of the compactness of the fiber material difficult to perform. The pure flow around of fiber flakes with heated gas leads because of the bad Thermal conductivity of natural fibers to an inhomogeneous heat transfer, i.e. the outer fibers of a flake become much warmed up more than those inside the flake. The thermal Preparation of a free on a perforated endless belt located fiber mixture by flowing through the fiber mixture with a heated gas is also difficult as the Pressurization of the fiber mixture only to a limited extent is possible, because exposed fiber flakes are heated from the Gas either flows around or blown away. The pressurization a freely hanging between two pairs of rollers sliver leads to a greatly increased flow resistance and thus to a poorly controllable heating of the fiber material.

With regard to natural fibers, it must also be noted that These are usually sensitive to heat, and thus their heat load in terms of duration and temperature as low as possible must be kept. On the other hand, because of the bad Thermal conduction of natural fibers to change the physical Conversion of plastics required heat as homogeneous as possible be introduced into the fiber mixture.

Object of the present invention is to avoid the above Disadvantages of the known from the prior art Method and the improvement of the heat input into the fiber material such that the fiber material heats as little as possible and the foreign substances made of plastic for their physical Conversion required amount of heat as quickly as possible can absorb, with the corresponding foreign substances inside the fiber material supplied the heat of transformation just as quickly should be like those in the outer region of the fiber material.

According to the invention, this object is achieved by a method which has the features of claim 1.

The foreign material containing plastic fiber material consists essentially of natural fibers, such as cellulose-rich ones Fibers, wool or silk. As cellulosic fibers come For example, cotton, flax or hemp in question. All the method is preferred for the purification of cotton fibers used. The loaded with plastic fiber material is present the process of the invention advantageously precleaned and dissolved into flakes.

The loosened, flake-like fiber material then passes through with the help of a continuous conveying a treatment line, where the foreign substances plastic their physical properties change so that their excretion from the fiber material means mechanical means is favored. For example, relax by the heat treatment, thermoplastic foreign substances such that they shrink and / or become brittle.

The fiber material fed to the process is preferably as loose, evenly distributed fiber mixture in form of flakes.

The foreign substances made of plastic originate, for example, from the product groups fibers, films, foams, deep-drawn parts and blow-molded articles. The inventive method is particularly suitable for the preparation of a thermoplastic containing fiber mixture. The thermoplastic foreign substances may consist of foamed or stretched thermoplastic material and preferably relate to plastics from the group of polyethylenes, polypropylenes, polyvinyl chlorides, polystyrenes, polyamides, polyesters, polyacrylonitriles, polycarbonates, or mixtures thereof.
The heating temperature for the inventive method, ie the temperature of the hot gas, is typically in the range of 110 ° C to 260 ° C. Preferably, the temperature of the hot gas is between 170 and 190 ° C. Optionally, the cotton can be treated with hot steam to prevent yellowing of the cotton at the temperatures mentioned. Hereinafter, the term hot gas also includes hot steam. The relaxation of stretched plastics caused by the heat treatment leads to their shrinkage. A chemical decomposition usually does not take place, but would also be conceivable. In most cases, the relaxation of thermoplastics is accompanied by a drastic change in the elastic properties, which manifests itself in a significant embrittlement after cooling.

The change in the physical effect caused by the heat treatment Properties of foreign substances allows their elimination from the fiber material by mechanical separation process. Such separation processes are known from the prior art and can, for example, a card, a cyclone with a Air flow classifier, a sieve unit or when sufficient parallel aligned fibers and the combing of the fiber material affect.

The continuous conveyor contains an apertured, endless transport organ. Preference is given as a transport organ perforated endless conveyor belt or a rotating screen drum used.

As hot gas is preferably a to the appropriate temperature preheated inert gas or hot air used. Further preferred is hot steam or a mixture of hot air and hot steam used. The hot steam preferably consists of water vapor. The hot gas is preferably at a temperature below the softening temperature of the foreign substances preheated.

The hot gas will be over at least part of the treatment line under such pressure by the fiber material and the transport organ directed that the fiber material exclusively under the action of a through the hot gas flow over the fiber material caused pressure difference on the transport organ liable. For example, the fiber material in the inventive Method by a on the fiber material opposite Side of the transport organ acting negative pressure sucked or by the dynamic pressure of the fibers conducted on the fiber material Hot gas flow pressed. The hot gas flow is preferred adjusted so that the pressure difference over the Fiber material between 10 mbar and 200 mbar. Especially Preferably, the pressure difference across the fiber material between 50 mbar and 200 mbar. As pressure difference over the fiber material is the pressure difference between the pressure at the free Surface of the lying on the transport organ fiber material and the pressure between the fiber material and the fiber material referred to the surface facing the transport member.

In a preferred embodiment of the inventive method the hot gas is conducted in a closed circuit, i.e. the hot gas flowing through the fiber material becomes conditioned (i.e., purified and to the required temperature heated) and for example by means of a blower again Surface of the lying on the treatment line fiber material fed. Here are the gas pressure, or the flow rate and the temperature of the hot gas adjustable.

An improved homogenization of the on the fiber material too Conductive airflow can be due to a uniform perforation of the transport organ and / or by a directly above the Fiber material located, additional Durchströmschikane for the hot gas can be achieved. The additional flow-through chicane is preferably on or just above the exposed surface arranged on the transport member fiber material. The flow-through baffle can be mounted stationarily stationary be, or move along with the fiber material concurrently. The Durchströmschikane, for example, a close above the Perforated sheet metal arranged on the fiber material or one on the fiber material represent scrolling drum. The flow-through chicane is preferably designed such that its flow resistance greater than the flow resistance of the fiber material.

In a further preferred embodiment, the on the Transport organ lying fiber material by means of compression metered compressed. For example, such a compression means at least one against the on the transport organ lying fiber material oppressive cylinder roll or the like represent, wherein the peripheral speed of the cylinder roller preferably corresponds to the speed of the transport member. For this purpose, a single or a plurality of such cylindrical rollers be used. Also suitable is a pair of rollers, which encloses the transport organ in between, i.e. two rollers, which from both sides of the transport organ press against each other.

However, as a means of compression also flow-through baffles can be used be moved, in particular with the fiber material Through baffles, which on the fiber material a certain Apply contact pressure and squeeze the fiber material in doses. Such Durchströmschikane represents, for example, a on the transport organ rolling smaller screen drum or a perforated endless conveyor belt. A predefined and metered compression of the fiber material causes, for example a homogeneous hot gas permeability of the fiber material. However, a local local compression of the fiber material can also for expressing or pressing in the fiber material serving cold or hot gas.

The compressing agents may also be preferred for incorporation be designed a hot gas flow. This is hot gas in the interior of the compression means, for example in the Interior of a pressure roller, initiated. Contains the pressure roller expediently radial openings through which the hot gas to the surface of the pressure roller and then into the fiber material can get. For this purpose, several consecutively arranged Compressing agents are used. That by the compression agent flowing hot gas can through the hot gas flow support the apertured, endless transport organ or replace it.

In a further preferred embodiment of the inventive Procedure, the fiber material is continuously using a pneumatic conveying means in a supply conveyor line supplied, then by means of a condenser from the conveyor, a conveying gas, separated and then depressurized into one Stowage given, from which it is taken continuously and the Treatment line is supplied. The removal of the fiber flakes from the stowage and placing the flakes on the transport organ happens preferably with a conveyor roller pair with two counter-rotating cylindrical rollers and optional downstream of an opening roller (needle set) for a uniform dissolution and distribution of the flakes.

The detachment of the fiber material from the transport organ at the end of Treatment route, for example, by means of a wedge-shaped Spatula, which can optionally be supported with Air nozzles, or a take-off roller pair with two in opposite directions rotating cylindrical rollers happen. More preferred is the from the transport member at the end of the treatment line detached fiber material fed to a pneumatic discharge conveyor line. Very preferred is as conveying gas in this pneumatic discharge conveyor line the same gas flow used previously was derived at the condenser.

The speed of the transport organ is in function of Length of the treatment path preferably adjusted such that the residence time of the fiber material on the treatment section. 2 to 15 s.

The supply of fiber material to the treatment section is preferably set such that the amount of fiber per unit area of the treatment section is between 60 and 600 g / m ² and in particular between 70 and 200 g / m ² .

The inventive method is suitable for implementation in a blowroom of a spinning mill. In the Vorwerk of a cotton mill For example, following the rough cleaning, or after mixing the flakes, or after Fine cleaning of cotton fibers are used.

The inventive method has the advantage that the Fiber material for the heat treatment is not present as a band and not be compressed, but in loose form is heat treatable as fiber flakes. Due to the low material density loose flakes, the fiber material is good of Hot gas to flow through, which is in terms of the fiber material inside and exteriors of a fiber flake a very homogeneous heating allowed within a short treatment period. With the flow resistance the transport organ and / or an additional Through-flow chicane can further homogenize the hot gas distribution become.

One for a continuous process for the thermal Preparation of fiber material for the subsequent excretion of foreign matter contained therein plastic suitable Device has the features of claim 14. A such device has a heat treatment device a continuous conveying means operatively connected to a source of hot gas on. In this case, the continuous transport with a Opened, endless transport member for transport of the fiber material. As an endless transport organ is suitable in particular a rotating screen drum or a perforated Endless conveyor belt.

In a further preferred embodiment, a plurality of such continuous conveying means are used. Very preferred In particular, two such continuous conveying means behind the other arranged, or the Heißgasbeaufschlagung is formed such that the fiber material is successively from both sides is acted upon with hot gas. With a serial arrangement can reduce the size of the system and the structure of the system be simplified. Also allows such a flow realize the fiber material from both sides, so that improves the penetration of the fiber material with hot gas becomes.

In case of using one or more sieve drums point whose drum surface preferably has a diameter of 1 m to 2.5 m up. The width of the sieve drum is preferably 1 m to 2 m.

Such a device may be a mechanical separation device for the heat-treated foreign substances, or a corresponding separation device can only in a later Process state of the spinning process to be installed.

The feed means for the supply of hot gas are preferred to the lying on the transport member fiber material part of a closed hot gas ring line with an integrated heating device and integrated means to regulate Pressurization of the hot gas. In this case, the pressurization of the hot gas, for example by means of a fan respectively.

Figur 1:

einen stark vereinfachten Querschnitt durch eine erfindungsgemässe Vorrichtung mit einer sich drehenden Siebtrommel;

Figur 2:

einen stark vereinfachten Querschnitt durch eine erfindungsgemässe Vorrichtung mit einer Förderbandvorrichtung.

Figur 3:

eine vereinfachte schematische Darstellung eines Querschnitts durch eine erfindungsgemässe Vorrichtung mit einer seriellen Anordnung zweier Siebtrommeln.

Figur 4:

eine vereinfachte schematische Darstellung eines Querschnitts durch eine erfindungsgemässe Vorrichtung mit zwei Walzenpaaren als Komprimiermittel zum dosierten Zusammenpressen des Fasermaterials.

Figur 5:

eine vereinfachte schematische Darstellung eines Querschnitts durch eine weitere erfindungsgemässe Vorrichtung mit zwei gleichlaufenden Endlosförderbändern.

The invention will be further exemplified with reference to Figures 1 and 2. Showing:

FIG. 1:

a greatly simplified cross-section through an inventive device with a rotating screen drum;

FIG. 2:

a greatly simplified cross section through an inventive device with a conveyor belt device.

FIG. 3:

a simplified schematic representation of a cross section through an inventive device with a serial arrangement of two screening drums.

FIG. 4:

a simplified schematic representation of a cross section through an inventive device with two pairs of rollers as compression means for the metered compression of the fiber material.

FIG. 5:

a simplified schematic representation of a cross section through a further device according to the invention with two concurrent endless conveyor belts.

According to FIG. 1, a screening drum 20 is designed as a hollow body and has as a transport member on a drum surface 23, which encloses a drum interior 21. The sieve drum 20 is in a manner not shown here in Arrow direction a rotatably mounted.

The outer region of the screening drum 20 can for example consist of two layers: an inner, mechanically stable layer with regularly arranged openings in the form of, for example, a perforated layer and an outer layer in the form of a covering with a fine mesh.
Over a part of the drum surface 23, a drum casing 24 is arranged. Through the drum casing 24 and the drum surface 23, a ring segment-shaped hot gas channel 28 is formed, which is connected to a hot gas supply line 16. In the embodiment shown in Figure 1, the hot gas discharge line 17 via connecting pipes 13 with a blower 11 for pressurizing the hot gas 30 and with a heating device 12 for heating Heating the hot gas 30 is connected, wherein the emerging from the heating device 12 hot gas 30 is connected via the hot gas supply line 16 with the hot gas channel 28. By the above-described hot gas guide a closed hot gas ring 14 is formed, with which the hot gas used for the heat treatment of the fiber material 15 30 processed and fed back to the hot gas channel 28, so that a closed hot gas circuit e is formed by the drum surface 23.

The supply of fiber-loaded fiber material 15 takes place in the direction of arrow b in a pneumatic feed conveyor line 4. The fiber material from a conveying gas in a Condenser 6 passed. In the condenser 6 or another analog Device for separating the conveying gas flow is the Fiber material 15 separated in a known manner from the conveying gas, so that the fiber material 15 without pressure in the direction of arrow c is ejected into the stowage 10 and in front of a lay-up roller pair 9 collects in a relaxed state. through the layup roller pair 9, the fiber material 15 on the Drum surface 23 of the screen drum 20 stored.

The from the hot gas channel 28 through the fiber material 15 and the Drum surface 23 flowing hot gas 30 is subject to a Pressure drop. This ensteht between the fiber material 15 and the drum surface 23 a negative pressure relative to the on the exposed surface of the fiber material 15 acting pressure, whereby the fiber material 15 is pressed against the drum surface 23 will stick there throughout the treatment route remains. The treatment section is through the segment the drum surface 23 defines which between the Auflegeort of the fiber material 15 on the drum surface 23 at Laying-on roller pair 9 and a detachment location of the fiber material 15 from the drum surface 23 at a take-off roller pair 18th lies.

The drum interior 21 is by means of a relative to the drum 20 fixed partition 25 in a pressure segment 22 and an inner chamber 26 divided. In this case, the pressure segment comprises 22 the treatment area adjacent the area of the drum interior 21. The pressure segment 22 is through the fan 11 via a connection pipe connected to a hot gas discharge pipe 17 13 constantly subjected to a negative pressure. The Laying and removal roller pairs 9, 18 are expediently in the inner chamber 26 adjacent area of the drum surface 23 arranged so that on the one hand, the loose laying of the Fiber material 15 on the drum surface 23 and on the other hand the detachment of the fiber material 15 from the drum surface 23rd is ensured without force. If necessary, the Inner chamber 26 for easier removal of the fiber material 15 am End of the treatment route by means of a not shown here Gas supply to be acted upon by an overpressure.

The detached from the removal roller pair 18 fiber material 15 with The heat-treated foreign substances made of plastic will be in more relaxed Mold in a pneumatic discharge conveyor line 32 in the arrow direction d delivered. Preference is given as conveying gas for the discharge conveyor line 32 derived in the condenser 6 conveying gas used. For this purpose, the conveyor 8 is derived from the condenser. 6 with the conveyor supply line 7 for the discharge conveyor line 32nd connected via connecting lines (not shown).

Figure 2 shows a cross section through an inventive Device with a perforated endless conveyor belt 19 as Transport element. The endless conveyor belt 19 is via conveyor rollers. 5 strained, is guided by these and driven in the direction of arrow a.

The fiber material 15 is by means of a laying roller pair 9 the Stowage 10 removed and depressurized on the endless conveyor belt 19 laid.

Over a portion of the endless conveyor belt 19 is a band formwork 29 arranged. Between the band formwork 29 and the endless conveyor belt 19 becomes an approximately semicircular ring segment formed, which serves as a hot gas channel 28. Close above the endless conveyor belt 19 located fiber material 15 is located in a segment of the hot gas channel 28 a curved Perforated plate 37 as Durchströmschikane. The hot gas channel 28 is supplied with hot gas 30 via the hot gas supply line 16. The Hot gas 30 flows out of the hot gas channel 28 in the arrow direction through the perforated plate 37, the fiber material 15 and the perforated Conveyor belt 19 in the interior 31 of the conveyor belt device. 3 Optionally, the hot gas in a closed circuit (not shown) reprocessed and the hot gas channel 28 be forwarded.

At the opposite end of the laying roller pair. 9 Heissgaskanales 28, a removal cylinder 27 is arranged, the at the end of the treatment section, the fiber material 15 from the endless conveyor belt 19 replaces. The treatment section relates to the between the laying roller pair 9 and the removal cylinder 27th lying belt surface of the endless conveyor belt 19th

According to FIG. 3, the heat treatment device 2 has two serially arranged sieve drums 20, wherein the sieve drums 20th are formed as a hollow body and as a transport member for the Fiber material 15 have a drum surface 23, a Drum interior 21 encloses. The drum interior 21 is in two segments, namely a pressure segment 22 and an inner chamber 26 divided. The pressure segment 22 takes that from the outside through the fiber material 15 and the drum surface 23 in the Drum interior 21 flowing hot gas 30 on. The inner chamber For example, 26 has the same pressure as that of the screen drum 20 ambient atmosphere or can with a certain Overpressure are applied to the fiber material 15 by means the removal roller pair 18 better from the drum surface 23rd replace. The screening drums 20 are rotatable in the direction of rotation a stored, with the direction of rotation of both screening drums runs opposite to each other.

Over the drum surface 23 is in the through the pressure segment 22 defined area in both screening drums 20 a drum casing 24 attached, which between the drum surface 23 and the drum casing 24 forms a hot gas channel 28. In the hot gas channel 28 each opens a hot gas supply line 16th

The supply of the fiber material 15 in the heat treatment device 2 takes place via a storage shaft 10. By means of a lay-up roller pair 9, fiber material is continuously applied to the Clockwise rotating drum surface 23 of a first sieve drum 20 filed. By the hot gas supply line 16 is the Hot gas channel 28 continuously supplied hot gas 30, which through the fiber material 15 lying on the drum surface 23 flows into the drum interior 21, from where the spent hot gas 15 discharged either as exhaust air or for reprocessing becomes. As a result of the hot gas flow that is above the pressure segment 22 located on the drum surface 23 lying fiber material 15 constantly applied with a pressure which the Fiber material 15 on the drum surface 23 is able to hold. A removal roller pair 18 releases the fiber material 15 at the end of Warming distance from the drum surface 23 and performs the fiber material 15 another layup roller pair 9 a second, counterclockwise rotating screen drum 20 to. By the opposite direction of rotation of the two arranged in series Sieve drums 20 will be the original against the first Drum surface 23 directed fiber material surface in the second screening drum 20 to the exposed fiber material surface, so that the fiber material 15 on the two consecutively arranged screening drums 20 mutually, i. from both sides, with hot gas 30 is applied, which in total to one particularly homogeneous hot gas loading of the fiber material 15th leads.

Figure 4 shows schematically a cross section through an inventive Heat treatment device 2 with a rotating Sieve drum 20 and two rolling on the drum Roller pairs. The roller pairs each have one in the direction of the arrow rotating compression roller 1 and one of the drum inside pushing against the compression roller 1, opposite rotating roller 36. Press the compression rollers 1 the fiber material 15 located on the drum surface 23 dosed together. The remaining heat treatment device corresponds essentially as shown in FIG. 1, wherein the device shown in Figure 4 no hot gas ring line 14 has.

The shown in Figure 4, rolling on the screen drum 20 Roller pairs each with a hollow cylindrical compression roller 1 and a hollow cylindrical counter-roller 36 each have one Hot gas connection 34, which has a gas supply cavity 33 of the Compression roller 1 with a gas discharge cavity 35 of the backing roll 36 connects with each other. The hot gas connection 34 closes the lying between the respective pair of rollers with the rollers 1, 36, compressed fiber material 15 and between the Rollers 1, 36 lying portion of the drum with a.

In the gas supply cavity 33 opens a hot gas supply (not drawn) and from the gas discharge cavity 35 leads a hot gas discharge line (not shown) away. That by the hot gas connection 34 flowing hot gas forms a secondary gas flow from, which in the fiber material located in the foreign material a change favoring their excretion of their physical Features supported. This secondary gas flow supports the effect of the hot gas channel 28 through the fiber material 15th and the drum surface 23 flowing into the pressure segment 22 Hot gas 30. The latter gas flow is also called called primary gas flow.

The gas supply cavity 33 of the compression rollers 1 may be opposite the hot gas channel 28 be tightly closed, or the compression rollers 1 may be formed as screening drums. If the Gas supply cavity 33 of the compression rollers 1 with respect to the hot gas channel 28 is formed tightly closed, this can the Gas supply cavity 33 supplied hot gas same chemical composition, have the same temperature and pressure, as the hot gas 30 of the primary gas flow, or can in terms of chemical composition, temperature or differ from the pressure of the hot gas 30 of the primary gas flow. If the compression roller 1 is formed as a screen drum is, if necessary, a separate hot gas supply is unnecessary in the gas supply cavity 33 of the compression roller 1, da the hot gas for the secondary gas flow through the as a sieve drum formed compression roller 1 in the gas supply cavity 33 can get. In the latter case, the compression roller 1 be used as a flow-through, i. e. in the hot gas connection 34, a particularly homogeneous flow of hot gas is formed.

When using several, on the Siebtrommeloberfläche 23rd Rolling compression rollers 1 may also be a part of the compression rollers 1 as a screening drum and another part opposite the Hot gas channel 28 may be formed as tightly closed. at Use of several, against the hot gas channel 28 tightly abgeschlosser Compression rollers 1 can be the chemical composition the hot gas introduced into the gas supply cavity 33, the hot gas temperature or the gas pressure in the individual compression rollers 1 or different in groups of compression rollers be.

According to FIG. 5, the heat treatment device 2 has two superposed, concurrent endless conveyor belts 38, 39 on, which are driven by means of conveyor rollers 5. The lower Endless conveyor belt 38 is opposite the upper endless conveyor belt 39 formed longer and protrudes from the upper conveyor belt 39 in the direction of the fiber material feed by a Auflegewalzenpaar 9 accordingly. The two endless conveyor belts 38, 39 are formed perforated. The upper conveyor belt 39 is opposite the lower conveyor belt 38 arranged in the vertical direction such that in between a hot gas channel 28 in the form of a Gap is formed. Between the two conveyor belts 38, 39 is the treatment zone, which in a first 43 and a second zone 44 is divided. Each zone 43, 44 is exemplary five flow chambers 40, wherein the flow chambers 40 a zone hot gas supply side and hot gas discharge side each via a Heissgaszufuhr- 41 and a Heissgasableitkammer 42 are interconnected. The hot gas supply chamber 41 The first zone 43 is located above the hot gas channel 28 and the hot gas discharge chamber 42 below it. In the second zone 44, the hot gas supply chamber 41 is below and the hot gas discharge chamber 42 above the hot gas passage 28. The hot gas supply chambers 41 are by means of hot gas supply lines 16 connected to a heating device 12. The Hot gas discharge chambers 42 are by means of hot gas discharge lines 17th connected to a blower 11. The blower 11 and the Heating device 12 are connected via a connecting line thirteenth connected together, leaving a closed Hot gas cycle is formed. The heat treatment device 2 can still cleaning filter (not shown) for the hot gas cleaning exhibit.

The fiber material 15 is continuously by means of a pneumatic Conveyor fed in a feed conveyor line 4, then separated by a condenser 6 from the conveying gas and then depressurized in the stowage 10 given from which it taken continuously with the help of a pair of rollers 9 and on the lower endless conveyor belt 38 is placed. The fiber material 15 is on the conveyor belt 38 lying in the first treatment zone 43, in which it by means of a top-down Hot gas flow is applied. In the first zone 43, the fiber material 15 by the application of hot gas 30 on the hot gas channel side surface of the lower conveyor belt 38 pressed. Conversely, the fiber material 15 in the second zone 44 by the application of hot gas 30 at the hot gas channel side surface of the upper conveyor belt 39th pressed. At the end of the second treatment zone 44 this dissolves Fiber material 15 due to gravity from the hot gas channel side Surface of the upper conveyor belt 39 and is over a to the terminal conveyor rollers 5 of the conveyor belts 38, 39 adjoining connecting channel in the discharge conveyor line 32 passed, or by the gas flow in the conveyor supply line 7 sucked into the discharge conveyor line 32. By the in 5, the heat treatment device 2 is the fiber material 15 consecutively from both sides with hot gas 30 subjected to what is a particularly homogeneous, fast and the fiber material 15 gentle heating of existing in the fiber material 15 Foreign substances made of plastic allowed.

Claims (22)

Process for the thermal treatment of fibrous material (15), in particular raw cotton, for the subsequent separation of foreign substances contained therein from plastic, in which the fibrous material (15) passes through a treatment section with the aid of at least one continuous conveying means (3, 20) and in such a way flows through a hot gas (30), that sets at the end of the treatment section at the foreign substances a precipitation favoring change in their physical properties, the fiber material (15) at the beginning of the treatment section loosely on an apertured, endless transport member (19, 23 , 38, 39) of a continuous conveying means (3, 20) and at the end of the treatment section are detached from the conveying member (19, 23, 38, 39) of a continuous conveying means (3, 20),
characterized in that
the hot gas (30) is passed through the fiber material (15) and the transport member (19, 23) over at least a part of the treatment line, that the fiber material (15) exclusively under the effect of the pressure difference caused by the hot gas flow over the Fiber material (15) on the transport member (19, 23, 38, 39) adheres. A method according to claim 1, characterized in that a drum surface (23) of a rotating screen drum (20) or a perforated endless conveyor belt (19) of a conveyor belt device (3) is used as the transport member. Method according to claim 1 or 2, characterized in that the fibrous material (15) is supplied continuously by means of a pneumatic conveyor, then separated from the conveyor by means of a condenser (6) and then passed without pressure into a storage shaft (10) from which it is continuously conveyed removed and the treatment line is supplied. A method according to claim 3, characterized in that the from the condenser (6) exiting pneumatic conveying means at the end of the treatment section from the transport member (19, 23, 38, 39) detached fiber material (15) is fed back as a pneumatic conveying means. Method according to one of claims 1 to 4, characterized in that the hot gas (30) is guided in a closed circuit (14), wherein the pressure and the temperature of the hot gas are adjustable. Method according to one of claims 1 to 5, characterized in that a hot steam, in particular hot steam, is used as the hot gas. Method according to one of claims 1 to 6, characterized in that for the homogenization of the hot gas flow directly on or above the exposed surface of lying on the transport member (19, 23) fiber material (15) from the hot gas (30) to be flowed through, stationary or with the fiber material (15) mitbewegte Durchströmschikane (37) is arranged. Method according to one of claims 1 to 7, characterized in that at least a portion of the on the transport member (19, 23) lying fiber material (15) is compressed by means of Kompriermiermitteln (1) metered. Method according to one of claims 1 to 8, characterized in that the fiber material (15) is deposited on the treatment path on at least two different transport members (19, 23, 38, 39) such that the fiber material (15) mutually with hot gas (30 ) is applied. Method according to one of claims 1 to 9, characterized in that the hot gas (30) is pressurized such that the pressure difference across the fiber material (15) between 10 mbar and 200 mbar, in particular between 50 mbar and 200 mbar. Method according to one of claims 1 to 10, characterized in that the hot gas (30) has a temperature of 110 to 260 ° C, and in particular a temperature between 170 to 190 ° C, having. Method according to one of claims 1 to 11, characterized in that the residence time of the fiber material (15) on the treatment section is 2 to 15 s. Method according to one of claims 1 to 12, characterized in that the amount of fibers per unit area of the treatment section is between 60 and 600 g / m ² and in particular between 70 and 200 g / m ² . Apparatus for the thermal treatment of fibrous material (15), in particular of raw cotton, for the subsequent removal of contaminants contained therein from plastic, comprising a heat treatment device (2) having at least one continuous conveying means (3, 20) in operative connection with a hot gas source (12) in that the fibrous material (15) is continuously heat-treatable in such a way that a change in its physical properties favoring the precipitation occurs, the continuous conveying means (3, 20) comprising at least one endless transport member (19, 23, 38, 39), and the device feed conveyor means (4, 6, 9, 10) for the loose laying of fiber material (15) on the transport member (19, 23, 38, 39) and means (18, 27) for detaching the fiber material (15) from the transport member (19, 23, 38, 39),
characterized in that
the heat treatment device (2) supply means (16) for supplying hot gas (30) to at least part of the fiber material (15) lying on the transport member (19, 23, 38, 39) and means (11) for controllably pressurizing the hot gas ( 30) such that hot gas (30) can be conducted under such a pressure by the fiber material (15) and the transport member (19, 23, 38, 39) that the fiber material (15) exclusively under the influence of such a hot gas flow ( 30) caused pressure difference over the fiber material (15) on the transport member (19, 23, 38, 39) is adhesively transportable. Apparatus according to claim 14, characterized in that the transport member is a drum surface (23) of a rotating screen drum (20) or a perforated endless conveyor belt (19, 38, 39) of a conveyor belt device (3). Apparatus according to claim 15 with a sieve drum (20), characterized in that the surface (23) of the sieve drum (20) has a diameter of 1 m to and 2.5 m, wherein the width of the sieve drum preferably 1 m to and with 2 m. Device according to one of claims 14 to 16, characterized in that the heat treatment device (2) over at least a part of the on the transport member (19, 23) lying fiber material (15) has a stationary or with the fiber material (15) mitbewegbare Durchströmschikane (37 ) for the hot gas (30). Device according to one of claims 14 to 17, characterized in that the heat treatment device (2) compression means (1) for a metered compression of at least a portion of lying on the transport member (19, 23) fiber material (15). Device according to one of claims 14 to 18, characterized in that the supply conveyor for loose laying of fiber material on the transport member (19, 23, 38, 39) a pneumatic supply conveyor line (4) for the supply of fiber material by means of a conveying gas, a condenser ( 6) for separating the fiber material (15) from the conveying gas, a stowage shaft (10) for receiving the fiber material (15) ejected from the condenser (6) and means (9) for removing fiber material (15) from the stowage shaft (10) and Have means (9) for placing the fiber material (15) on the transport member (19, 23, 38, 39). Device according to one of claims 14 to 19, characterized in that the supply conveyor means for placing the fiber material (15) on the transport member (19, 23, 38) and the means for detaching the fiber material from the transport member (19, 23, 39) one each Roller pair (9, 18) with two rollers rotatably mounted in opposite directions. Device according to one of claims 14 to 20, characterized in that the supply means (16) for the supply of hot gas (30) on the transport member (19, 23, 38, 39) part of a closed hot gas ring line (14) with an integrated heating device ( 12) and integrated means (11) for controllably pressurizing the hot gas (30). Device according to one of claims 14 to 21, characterized in that the heat treatment device (2) at least two different, in operative connection with a hot gas source continuous conveying means (3, 20) each having an endless, apertured transport member (19, 23, 38, 39).

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