EP3017104A1

EP3017104A1 - Method for retrofitting and operating a device for producing a non-woven fabric

Info

Publication number: EP3017104A1
Application number: EP14731241.7A
Authority: EP
Inventors: Herbert Aust; Kai PÖHLER
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2013-07-04
Filing date: 2014-06-17
Publication date: 2016-05-11
Anticipated expiration: 2034-06-17
Also published as: WO2015000687A1; CN105408539A; CN105408539B; EP3017104B1

Abstract

The invention relates to a method for retrofitting a device for producing a non-woven fabric, said device comprising a former for forming a non-woven fabric, suction pipes and/or suction boxes for dewatering the non-woven fabric and a drying device, said method comprising the following steps: - removing all the suction pipes and/or suction boxes arranged upstream of the drying device, and - installing a belt press between the former and the drying device, the belt press comprising a roller, around which are wrapped at least one inner belt adjoining the roller and an outer press belt, wherein a non-woven material web resulting from the non-woven fabric formed in the former can be arranged, and preferably are arranged, at least in the region of the roller between the inner belt and the outer press belt, wherein the press belt can be pressed, and preferably is pressed, against the roller with a belt tension of at least 15 kN/m. A method for operating the device which is retrofitted according to the above-mentioned method, comprises the steps of: - forming a non-woven fabric in the former, - further dewatering of the non-woven fabric material web resulting from the non-woven fabric in the belt press, and - guiding the non-woven fabric material web through the drying device.

Description

METHOD FOR RECONSTRUCTING AND OPERATING A DEVICE FOR

The present invention relates to a method for converting a device comprising suction tubes and / or suction boxes for producing a nonwoven fabric in order to increase the production capacity and energy efficiency of the device and to operate the device. A nonwoven web is a web of limited length fibers, continuous filaments or cut yarns of any kind and of any origin, which are in some way joined together to form a nonwoven (ie, a fibrous web) and somehow bonded together have been. Nonwoven fabrics include fiber webs made by interlacing yarns such as those used in weaving, knitting, knitting, lace making, braiding, and tufted fabric making. Also films and papers are not among the nonwovens. Known processes for the production of nonwovens generally include nonwoven formation, nonwoven bonding and subsequent dewatering. Different methods of web formation are, for example, in WO

2007/018960 A2. In this case, the nonwoven can be formed in particular by a dry process, a wet process and / or an extrusion process. In principle, any combinations of such web-forming methods are also conceivable. The subsequent nonwoven consolidation can be effected, for example, mechanically or by the so-called hydroentanglement process, which is also called "spunlacing". In principle, however, other solidification methods are also conceivable. In the hydroentanglement process, the formed web is solidified by entangling the fibers, the entangling being effected by swirling, in particular by the fact that focused high-pressure water jets act on the web.

In particular, after such solidification by the hydroentanglement process, the formed nonwoven web has a relatively high

Moisture, which must then be removed again from the web.

In order to reduce the costs for the subsequent drying process and in particular a subsequent thermal drying, suction tubes or suction boxes subjected to vacuum have hitherto been used following the hydroentanglement. With such suction tubes or suction boxes wanted to increase the dry content of the nonwoven web as much as possible, without sacrificing volume.

However, such drainage using suction pipes or suction boxes brings a number of disadvantages. So the drainage performance of suction boxes is limited. Nevertheless, they are used because they practically do not influence the product quality parameters, whereas a mechanical pressing used for dewatering would have a negative effect on many products. Due to the limited drainage capacity of suction pipes or

Suction boxes can make the subsequent dryer section in terms of production capacity to a bottleneck. Conventional suction tubes or suction boxes comprehensive devices for the production of nonwovens have a production capacity of only 700 to 900 kg / m / hr. on. To be competitive, these systems must be rebuilt. Currently, this problem is addressed by increasing the drying capacity. However, increasing the drying capacity in existing equipment is not easy because in most of these systems it requires the installation of one or more additional Through Drying (TAD) dryer cylinders, but this is disadvantageous because such dryer cylinders are very large However, available space in existing nonwoven manufacturing facilities is limited.

Another disadvantage of suction tubes or suction boxes is that destroyed by this the desired uniform moisture profile of the nonwoven web or at least impaired, which in particular air losses at the web edges due to a non-constant width of the web and on the technology of some suction tubes or boxes is due. A non-uniform moisture cross-section can bring about limitations of the production process, in particular with regard to thermal solidification. The air loss at the material web edges also brings a high energy consumption with it. Depending on the basis weight, nonwoven fabric composition and structure of the nonwoven material web, which may also be structured or perforated, for example, the dry content of the nonwoven material web obtained after dewatering is limited. As a result of the relatively high vacuum, it may be present on the transfer belt concerned, via which the nonwoven web is fed via the suction tubes or boxes, which is usually a fabric belt, a forming fabric or a nonwoven structuring and / or perforating structuring belt, to a loss of fibers by so-called "fiber plucking" come. The plucked fibers pollute the wastewater and are lost to the manufacturing process. In addition, these fibers entail additional contamination of the water reclaimed for hydroentanglement, requiring additional filtration steps and a more elaborate recycle system, eg, where fresh pulp must be added. Fiber losses occur mainly as a result of the air At the edges of the nonwoven web, cracking and / or breaking of the fibers and suction of the fibers into the suction boxes. For certain products, such as those used for the substance mixtures, in particular the relatively large suction forces lead to fiber loss.

Fibers drawn into the dewatering system tend to contaminate the water used for hydroentanglement and make recovery and filtration more difficult, particularly when using fiber pulp.

For example, DE 10 2006 042 507 A1 discloses the use of a shoe press for dewatering a nonwoven material web. Although such a shoe press, viewed in the web running direction, has an extended press nip or press nip, as compared to a nip. Due to the relatively high pressure of the shoe press, however, it comes before the press nip the shoe press to a disturbing water retention. In addition, the relatively high pressure of the shoe press leads to a reduction in the volume of the nonwoven fabric.

The invention is therefore based on the object, a method for converting an existing apparatus for producing a nonwoven fabric, with which from an existing, suction tubes and / or suction boxes comprehensive device an improved and in particular more efficient apparatus for producing a nonwoven fabric is obtained, and a method for To operate the device thus converted equipped, which does not have the aforementioned disadvantages and in particular - while avoiding a water jam - leads to an efficient and cost-effective drainage of the formed nonwoven web and a nonwoven web with the largest possible volume and with a uniform moisture profile , It should in particular already before the dryer section as high as possible dry content of the nonwoven web to be achieved in order to limit the number of large and bulky drying cylinders and thus optimally use the available space for the device. Furthermore, the total energy consumption should be reduced. In addition, the fiber losses should be kept as low as possible, the total dewatering efficiency and the drying efficiency should be increased and the production capacity of the device can be increased.

According to the invention, this object is achieved by a method for converting a device for forming a nonwoven, suction tubes and / or suction boxes for dewatering the nonwoven fabric and a drying device comprising apparatus for producing a nonwoven fabric according to claim 1 and by a method for operating a so converted device for the production a nonwoven fabric according to claim 13.

According to the invention, a method for converting a device for producing a nonwoven comprising a former for forming a nonwoven, suction tubes and / or suction boxes for dewatering the nonwoven and a drying device comprises the following steps:

- Remove all arranged upstream of the drying device suction pipes and / or suction boxes and

Installing a belt press between the former and the drying device, the belt press comprising a roller around which at least one inner band and an outer press belt are wound, wherein a nonwoven material web formed from the web formed in the former at least in the region the roll can be arranged and preferably arranged between the inner band and the outer press belt, and, wherein the press belt can be pressed and preferably pressed against the roll with a belt tension of at least 15 kN / m. It goes without saying that in carrying out the method the

Nonwoven material web and the bands run around the roller, which is why both the inner band and the outer press belt are preferably designed as endless belts.

For the purposes of the present invention, nonwoven is understood to mean a nonwoven fabric of low consistency obtained directly by molding, whereas a nonwoven fabric is understood as meaning a nonwoven already having a higher consistency than and having preferably solidified nonwoven immediately after shaping.

For the purposes of the present invention, belt tension of the outer press belt is understood to mean the quotient of the tension applied to the press belt and the width of the press belt, in accordance with the usual use of this term.

By according to the invention, the suction pipes and / or suction boxes arranged all upstream of the drying device are removed and replaced by a belt press arranged between the former and the drying device and configured as described above, the disadvantages associated with suction tubes and suction boxes, in particular limited drainage capacity, limited production capacity, large space requirement, production of nonwovens with non-uniform moisture cross profile, fiber loss in the production by "fiber plucking" and the like, overcome and it is obtained a device with which a nonwoven fabric efficiently and inexpensively with gentle, uniform and efficient dewatering of the formed nonwoven material web and under Forming a nonwoven web with a very large volume and having a uniform moisture cross profile is obtainable. In this case, a very high dry content of the nonwoven material web is achieved with the device thus converted, especially before the dryer section, so that the number of large and bulky drying cylinders to a maximum of one can be limited and so the space available for the device can be used optimally. For this reason, the space in the device released by the removal of the suction tubes and suction boxes is sufficient to integrate the new device parts, namely belt press, into the device without the need for additional space. In addition, replacement of the suction tubes and suction boxes by the belt press is more effective in terms of drainage performance than replacing the suction tubes and suction boxes with one or more additional drying cylinders such as TAD cylinders or the like. Overall, the thus converted device has a significantly reduced energy consumption. In addition, hardly any fiber losses occur during their operation.

In order to allow a particularly gentle and uniform dewatering of the nonwoven material web in the belt press, it is proposed in development of the invention that the roller of the belt press is designed for dispensing or receiving drying fluid with an open surface and the belts of the belt press as compared to drying fluid and preferably air and / or water vapor permeable belts are formed to allow a drying fluid to flow through the permeable belts and the nonwoven web simultaneously with the pressing of the nonwoven web against the roll by a pressure differential between the roller and the outer press belt can.

In addition, it is preferred that at least one (endless) band wrapped around the drum of the belt press is permeable to water or adapted to receive water to absorb and / or accumulate the water produced by the mechanical press in the belt press to let pass.

According to a particularly preferred variant of this embodiment, the roller of the belt press is designed as a suction roll so that the drying fluid starting from preferably a drying fluid hood at least through the permeable outer press belt, the nonwoven web and the permeable inner band can be sucked into the suction roll. In addition to the drying fluid, the water dehydrated in the belt press is expediently sucked or guided into the suction roll or the permeable inner band.

According to another particularly preferred variant of this embodiment, the roller of the belt press is designed as a blow roll so that the drying fluid can be blown from the blow roll at least through the permeable inner band, the nonwoven material web and the permeable outer press belt preferably to a hood. In addition to the drying fluid, the water dewatered in the belt press is expediently also blown or guided into the hood or the permeable outer band. Preferably, a means for solidifying the formed web to a nonwoven web is disposed between the former and the belt press to solidify the web formed in the former prior to further dewatering in the belt press. In this case, the solidification device may be a mechanical hardening device and particularly preferably a hydroentangling device.

The dewatering performance of the belt press depends in particular on the roll diameter, the rolling rotational speed and the wrap angle, ie the angle at which the nonwoven material web wraps around the roll. In particular, good results are obtained when the diameter of the roller of the belt press is in a range of 500 mm to 1400 mm, and preferably in a range of 750 mm to 1200 mm. In a further development of the inventive concept, it is proposed that the nonwoven material web is transferred in a closed train from the former to the belt press and preferably as far as the drying device. This can be achieved particularly simply by transferring the nonwoven material web from the former to the belt press and preferably to the drying device via a single transfer belt, such as a forming screen. In order to be able to dry the nonwoven web further dewatered in the belt press to the final dry content, at least one thermal drying device is preferably provided downstream of the belt press. Good results are obtained in particular when the thermal drying device is a TAD ("through air drying") or air drying unit or a flat bed oven

In order to achieve the most space-saving nonwoven fabric manufacturing device, it is provided according to a further particularly preferred embodiment of the present invention that the thermal drying device comprises not more than one drying cylinder and / or TAD through-flow.

If further dewatering is necessary or expedient in addition to that achieved by the belt press and the drying device, an additional dewatering press may, for example, be provided between the belt press and the thermal drying device. In this embodiment, in the dewatering press, preferably, a line force in a range of 20 kN / m to 100 kN / m, and preferably a line force in a range of 50 kN / m to 90 kN / m can be generated. A further subject matter of the present invention is a method for operating a device converted according to the method described above for producing a nonwoven fabric, which comprises the following steps:

Forming a web in the former,

further dewatering of the nonwoven fabric web resulting from the web, wherein the further dewatering of the nonwoven web comprises the dewatering in the belt press, wherein the nonwoven web is disposed at least in the region of the roller between the inner band and the outer press belt and the press belt with one

Belt tension of at least 15 kN / m pressed to the roller and thereby the nonwoven web and the inner band are pressed against the roller, and

Passing the nonwoven web through the dryer to bring the nonwoven web to the final dry content.

Due to this embodiment of the method results in a total of more efficient, cost-effective drainage of the formed nonwoven material web. In addition to the advantages already described above in comparison to suction tubes and suction boxes, the advantages of the method according to the invention are avoided with the method according to the invention, while avoiding the water jam which has hitherto occurred, in particular in connection with a shoe press, compared with the use of a shoe press - achieved a larger volume of the produced nonwoven material web, since the pressure in the extended press nip of the belt press is lower than in a shoe press. However, as a result of the longer residence time of the nonwoven material web in the nip compared to the use of a shoe press, efficient drainage with a high degree of dewatering is ensured despite the lower compacting pressure. Due to this, a thermal drying device, which may be provided after the belt press, such as a TAD (Through Air Drying) - or air drying unit, only a very small amount of energy. In addition, in the inventive method due to the belt press used in comparison to the methods known from the prior art, a very gentle and - based on the surface of the nonwoven material web - very uniform drainage achieved, so that an impairment or even destruction of the fiber structure reliable is prevented. Due to this, fiber losses as well as contamination of the waste water are kept to a minimum. Moreover, with the method according to the invention, an improved moisture cross profile is also obtained for the nonwoven fabric formed.

The inventive method also makes it possible to transfer the nonwoven material web with a higher solids content of the final, especially thermal drying device, whereby the machine speed is increased in the dryer section. Due to the reduced pressure in the belt press, the volume of the nonwoven web is reduced by no more than 10% in the dewatering. Thus, the solids content of the nonwoven web can be increased relative to the water content by more than 10% compared to the usual dewatering by suction boxes, resulting in a higher production capacity, energy consumption is reduced and the provision of additional or more expensive drying facilities is avoided.

According to a very particularly preferred embodiment of the present invention, the roller of the belt press is designed for dispensing or receiving drying fluid with an open surface and are used as belts of the belt press against drying fluid and preferably against air and / or water vapor permeable belts pressing the nonwoven web against the roll, a drying fluid is forced through the permeable webs and nonwoven web, and way by generating a corresponding pressure difference between the roller and the outer press belt. By additionally loading the nonwoven material web in the belt press by the drying fluid, the efficiency of gentle and uniform dewatering is further increased without sacrificing the volume.

In principle, any inert gas or aerosol can be used as the drying fluid, with good results, in particular with air and / or steam.

If air is used as the drying fluid, it may, for example, have ambient temperature. Alternatively, hot air may be used as the drying fluid, preferably hot air at a temperature in a range of 50 ° C to 250 ° C, more preferably at a temperature in a range of 150 ° C to 250 ° C, and more particularly preferably at a temperature in a range of 175 ° C to 225 ° C, such as at a temperature of about 200 ° C.

If steam is used as the drying fluid, it is preferably used in a ratio of steam weight / weight of the nonwoven material web of up to 2 kg steam / kg nonwoven material web and preferably in a ratio steam weight / weight of the nonwoven material web of 0.1 to 1 kg steam / kg nonwoven material web, such as in a ratio steam weight / weight of the nonwoven material web of about 0.5 kg steam / kg nonwoven material web used.

As stated, a drying fluid is preferably pressed through the nonwoven web in the belt press simultaneously with the mechanical pressurization, wherein the roller of the belt press for dispensing or receiving the Drying fluid is designed with an open surface. It can be used as a roller, in particular a suction roll or a blow roll.

If the roller of the belt press is designed as a suction roll, the drying fluid is expediently sucked or guided into the suction roll, starting from a drying fluid hood, at least through the permeable outer press belt, the nonwoven material web and the permeable inner band. For this purpose, the suction roll is preferably with a negative pressure (ie, a difference between atmospheric pressure and the pressure prevailing in the suction roll) in the range of 0.25 bar to 0.6 bar and particularly preferably with a negative pressure in the range of 0.30 to 0.55 bar, such as with a negative pressure of about 0.45 bar, applied.

If the roller of the belt press is designed as a blow roll, the drying fluid is preferably blown out of the blow roll at least through the permeable inner (endless) belt, the nonwoven material web and the permeable outer (endless) belt preferably in a hood , In this embodiment of the present invention, it is preferred that the drying fluid at a pressure in the range of 0.25 bar to 0.6 bar, and more preferably at a pressure in the range of 0.30 bar to 0.55 bar, such as for example, with a pressure in the range of about 0.45 bar, above atmospheric pressure through the permeable inner band, through the nonwoven web and through the permeable outer press belt is blown to the hood. When the nonwoven material web in the belt press, which is preferred as stated above, is subjected to a drying fluid in addition to the pressurization, the pressure exerted on the nonwoven web also depends, inter alia, on the flow of drying fluid. In order to achieve a particularly good, gentle and uniform drainage, it is proposed in a further development of the inventive idea in this embodiment, that through the belts a drying fluid flow in a range of 100 m ³ / (min m ² ) to 300 m ³ / (min m ² ), preferably from 150 to 250 m ³ / (min m ² ) and particularly preferably from about 210 m ³ / (min m ² ) is generated. If the roller of the belt press is still surrounded by one or more other (endless) belts in addition to the inner and the outer (endless) belt, then these other (endless) belts must also be permeable to the drying fluid, provided that the nonwoven fabric Material web in the belt press to be acted upon by such a drying fluid, which - as stated above - is particularly preferred.

On the one hand to achieve a sufficiently high degree of dewatering, but on the other hand perform the drainage as gently and evenly, it is provided according to a particularly preferred embodiment of the present invention that in the process at least serving as a press belt outer (endless) band with a belt tension of 20 to 100 kN / m, preferably with a belt tension of 25 to 75 kN / m and particularly preferably with a belt tension of 40 kN / m to 50 kN / m is pressed against the roll of the belt press.

With regard to a sufficiently good, but at the same time as gentle and uniform dewatering, it is particularly advantageous if in the belt press on the nonwoven material web, a mechanical pressure of less than 140 kPa, in particular less than 100 kPa and preferably less than 90 kPa , but of more than 30 kPa and preferably more than 45 kPa is exercised. With such a low pressure, in particular a higher volume of the nonwoven fabric is achieved while avoiding the water accumulation occurring in shoe presses, because due to the low pressure no significant compaction of the

Nonwoven fabric and therefore no significant volume loss occurs. Also in view of a sufficiently good, but at the same time as gentle and uniform drainage, it is proposed in development of the invention, the residence time of the nonwoven material web in the extended press nip of the belt press on between 0.05 sec and 0.5 sec set. With such a relatively long residence time, an efficient drainage is ensured despite the relatively low pressure and the correspondingly gentle treatment of the nonwoven material web.

According to a particularly preferred embodiment of the present invention, the nonwoven material web is dewatered in the belt press by at least 20%, preferably by 30 to 75% and particularly preferably by 33 to 50%. In this case, this degree of dewatering denotes the percentage weight loss in the dewatering based on the total weight of the nonwoven material web prior to dewatering in the belt press.

In certain cases, it may be advantageous if the belt press with only two roll wrapping the (endless) provided bands and the nonwoven material web between these two (endless) bands and the bands is arranged touching. In this case, both the inner (endless) belt and the outer press belt contact the nonwoven web.

In an alternative embodiment, the belt press except the inner and the outer (endless) band may also be provided with at least one further (endless) band wrapping the roller in a predetermined wrap angle. In this case, the at least one further (endless) band can be arranged in particular between the outer press belt and the nonwoven material web.

Preferably, the (endless) bands wrapping the roller of the belt press comprise at least one felt belt and / or a fabric belt. It is It is particularly advantageous if a felt belt is used as the inner band of the belt press (endless). This also applies in particular if the nonwoven material web in the belt press is simultaneously passed through by a drying fluid and a suction roll is used as the roller of the belt press. If a blow roll is used as the roll, it is possible in particular for at least one outer (endless) band, which is viewed behind the nonwoven material web, to be provided as a felt band in the direction of flow of the drying fluid. Dewatering on a felt belt results in a substantially more uniform moisture cross profile than is the case, for example, in the case of dewatering by means of a suction box. In addition, with the drainage of a felt and the fiber losses are reduced.

In particular, in the case that the nonwoven material web in the belt press is preferably acted upon simultaneously by a drying fluid, all wound around the roller of the belt press (endless) belts for the drying fluid are made permeable or permeable.

As an outer (endless) band of the belt press, for example, an at least substantially smooth belt and preferably a smooth forming belt can be used.

If a structured and / or perforated nonwoven fabric is to be produced by the method according to the invention, it is provided according to a preferred embodiment of the present invention that at least one of the nonwoven fabric Web-contacting (endless) band of the belt press is provided as a structured band by which the nonwoven web is structured and / or perforated accordingly. If the nonwoven material web in the belt press is preferably also subjected to a drying fluid simultaneously with the pressurization and more than two permeable (endless) belts are wound around the roller of the belt press, these (endless) belts can be viewed in particular in the direction of flow of the drying fluid For example, a permeable (endless) belt, an endless smooth forming fabric, an endless permeable fabric belt, and an endless permeable felt belt. In principle, however, it is also possible to provide fewer or more (endless) bands and / or a different sequence of these (endless) bands. According to a preferred embodiment of the present invention, the roller of the belt press is designed as a suction roll and comprise the roll-wrapping belts in the direction of flow of the drying fluid a) a permeable press belt stretched around the roll, a permeable fabric belt and a permeable felt belt, or

b) a permeable press belt stretched around the roll, a permeable wire belt, a permeable fabric belt and a permeable felt belt, or

c) a permeable press belt stretched around the roll, a permeable felt belt, a permeable fabric belt and a permeable felt belt, or

d) a permeable felt press belt stretched around the roll, a permeable fabric belt and a permeable felt belt.

According to another preferred embodiment of the present invention, the roller of the belt press is designed as a blow roll and comprise the belts wrapping the roll in the direction of flow of the drying fluid a) a permeable press belt stretched around the roll, a permeable fabric belt and a permeable felt belt, or

d) a permeable felt press belt stretched around the roll, a permeable fabric belt and a permeable felt belt. The (endless) bands of the belt press are suitably looped around the roller over the same angle of wrap.

Regardless of whether the wrap angle of the individual bands are the same or different, it is proposed in development of the invention that the wrap angle of the inner band and / or outer press belt around the roller in a range of 90 ° to 180 ° and in particular in a Range of 100 ° to 120 ° is selected. As a result, a residence time of the nonwoven material web required for a sufficiently high and at the same time gentle, uniform dewatering is achieved in the press nip of the belt press. In principle, the residence time of the nonwoven material web in the press nip at the same roll diameter and the same roll revolution speed is the greater the greater the wrap angle of the belts. According to a further particularly advantageous embodiment of the method according to the invention, the diameter of the roller of the belt press is selected in a range of 500 mm to 1400 mm and preferably in a range of 750 mm to 1200 mm. Since the pressure exerted on the nonwoven web in the belt press depends inter alia on the angle of wrap of the (endless) belts and on the diameter of the roller of the belt press such a relatively large diameter a relatively long press nip and a correspondingly efficient dewatering due to the longer residence time of the nonwoven material web in the press nip. In principle, the greater the diameter of the roll, the greater the residence time of the nonwoven material web in the press nip at the same wrap angle of the belts and the same roll revolution speed.

After or downstream of the belt press, the nonwoven material web can be guided in particular by at least one TAD ("through air drying") or air drying unit or a flat bed furnace as a thermal drying device. In this case, the nonwoven material web can be brought by such a thermal drying device in particular to the final dry content.

If required, the nonwoven material web can be guided through an additional dewatering press between the belt press and such a thermal drying device. In such an optional additional dewatering press, a line force in a range of 20 kN / m to 100 kN / m, and more preferably a line force in a range of 50 kN / m to 90 kN / m, is preferably produced to provide a gentle and uniform, but nevertheless to achieve strong drainage.

According to a further preferred embodiment of the device according to the invention, the nonwoven material web is guided in the inventive method in a closed train of the former at least up to the belt presses and preferably up to one of these downstream thermal drying device. In this case, the transfer of the nonwoven material web from the former to the belt press or up to this downstream thermal drying device via a single transfer belt. According to a further preferred embodiment of the device according to the invention, the transfer belt is formed by the forming fabric on which in the former the fleece is formed. In particular, in the case that the nonwoven material web is guided in a closed train at least up to the belt press, a hydroentanglement can be omitted. In the former of the belt press former the nonwoven fabric can in particular also with a relatively low consistency on a smooth forming fabric or a structured, the nonwoven according structuring and / or perforating Formiersieb with a solids content of 0.01 to 0.1 wt .-% based on 100 wt .-% of the resulting web are formed.

In this case, the nonwoven fabric can be formed in the former by any method known to those skilled in the art, preferably by a dry method, wet method and / or an extrusion method. For example, the nonwoven may be formed in the former at least partially by a wet process, in which the fibers are in particular suspended in water and deposited on a water-permeable support.

As an alternative or in addition to this, the nonwoven in the former can also be aerodynamically formed at least partially. The fleece is formed by depositing fibers by means of an air flow on an air-permeable base.

Alternatively or in addition to this, the nonwoven in the former can also be formed at least partially mechanically. In this case, it may be formed, at least in part, from carded or carded piles, which are laid one on top of the other, or formed by carding machines.

Alternatively or additionally, the nonwoven may be at least partially formed by the so-called spunbond method in which the nonwoven by forming fibers spun from a polymer melt passing through nozzles and drawn by means of cold air and / or mechanically drawn. As an alternative or in addition to this, the nonwoven in the former can finally be formed at least partially by the so-called melt-blow process. In this case, the nonwoven fabric is formed by depositing fibers which are directly spun from a polymer melt passing through nozzles and drawn to rupture by means of hot air streams.

In principle, the nonwoven fabric may be formed in the former not only by one of the aforementioned methods but also, in particular, by any combination of two or more of said methods. Subsequently, i. after its formation in the former and prior to further dewatering, the formed web may be consolidated by a consolidation process which preferably comprises mechanical consolidation and / or hydroentanglement. In hydroentanglement, the formed web is consolidated by entanglement of fibers to the nonwoven web which is accomplished by tumbling, in particular by the use of focused high pressure water jets on the web. Advantageously, the fleece can be simultaneously structured and / or perforated by the application of water jet. A hydroentanglement, however, is not mandatory and can be omitted in particular when the nonwoven fibrous web is transferred in a closed train, such as by a single transfer belt, at least up to the belt press.

The material input into the former can i) at least partially from natural fibers, preferably from northern bleached kraft pulp (NBKP), hardwood pulp (LBKP), pulp from abaca fibers or cotton, ii) at least partially artificial fibers, preferably of viscose, iii) at least partially of synthetic fibers, preferably of polyester or polyamide, iv) at least partially of mineral fibers, preferably glass fibers, v) at least partly of carbon fibers and / or vi) of a mixture of any of the foregoing consist of these substances.

In this case, the substance entry into the former can advantageously at least partially consist of fibers which are longer than 2 mm, preferably longer than 3 mm and particularly preferably longer than 4 mm.

According to a further preferred and expedient embodiment of the method according to the invention, in particular for producing a nonwoven material web having a basis weight of greater than 50 g / m ² , preferably greater than 80 g / m ² and particularly preferably greater than 100 g / m ² the

Nonwoven material web before or after the belt press additionally guided over a vacuum applied suction roll.

In conclusion, i. After the last drying step, the nonwoven fabric can still be thermally and / or chemically solidified, if this requires the subsequent use of the nonwoven fabric.

The invention will be described in more detail by means of embodiments with reference to the accompanying drawings; FIG. 1 shows a schematic representation of a conventional apparatus for the production of nonwovens, FIG.

Fig. 2 is a schematic representation of a first exemplary

Embodiment of an inventively retrofitted device and a schematic representation of another exemplary embodiment of the belt press of the device according to the invention retrofitted with a above the roller of the belt press arranged hood for dispensing or receiving of drying fluid.

Fig. 1 shows a schematic representation of a conventional apparatus 10 for producing nonwovens with a former 12, a Wasserstrahlverfesti- supply device 14, a plurality of suction tubes or suction boxes 16 comprehensive drainage device 18 and two thermal drying devices 20, namely two TAD or air drying units, a Dipping bath 22 for charging the dried nonwoven material web with a finishing agent and a winding device 24.

In the forming machine 26 comprising a former 12, the nonwoven fabric is formed by the wet process with a low consistency.

In this known device 10, in particular due to the suction pipes or boxes 16 comprehensive drainage device 18, the aforementioned problems arise.

In order to overcome these problems or disadvantages, a device for producing a nonwoven fabric configured as described above according to the prior art is converted according to the invention by the following steps:

Removing all upstream of the drying device 20 is arranged

Suction pipes and / or suction boxes 16 and

Installing a belt press between the former 12 and the drying device 20, wherein the belt press comprises a roller to the at least one applied to the roller inner band and an outer Press belt are wound, wherein a nonwoven web formed from the web formed in the former, at least in the region of the roller between the inner band and the outer press belt arranged and arranged nen arranged, and, wherein the press belt with a belt tension of at least 15 kN / m pressed to the roller and preferably pressed.

From FIG. 2, the basic principle of the nonwoven fabric production carried out according to the invention with the device according to the invention is first given by way of example.

Thereafter, the web is formed in a former 28 of a subject apparatus 30 for producing nonwoven webs by a particular method or combination of such methods. The nonwoven formed is, for example, consolidated mechanically, by means of a hydroentanglement device 32 and / or the like, and then the dewatered nonwoven material web is further dewatered. However, as shown in the following, solidification is not always mandatory. Further dewatering of the nonwoven web formed from the formed web comprises dewatering by means of a belt press 34 having a roller 36 around which at least one inner endless belt 40 contacting the roller to form an elongated press nip 38 over a respective wrap angle and an outer belt press belt Endless belt 42 is looped.

In the former 28, the nonwoven may be formed in particular by a dry process, a wet process and / or an extrusion process. The outer endless belt 42 of the belt press 34, which serves as a press belt, is tensioned around the roller 36 or pressed against this roller 36 with a belt tension of at least 15 kN / m for generating a mechanical pressure on the nonwoven material web lying between the two endless belts 40, 42 , By this press belt 42, the nonwoven fabric web and the roller 36 touching inner endless belt 40 are pressed against the roller 36.

Preferably, simultaneously with the mechanical pressurization of the nonwoven web by the press belt 42 of the belt press 34, a drying fluid is forced through the endless belts 40, 42 and the nonwoven web by creating a pressure differential between the roller 36 and the outer press belt 42 In order to make this possible, the endless belts 40, 42 in the present case are permeable to the drying fluid, ie permeable to the drying fluid. In addition, in this embodiment, the roller 36 of the belt press 34 is designed to discharge or receive the drying fluid having an open surface. It may in particular be formed by a suction or blowing roll.

In addition, it is preferred that at least one (endless) belt 40, 42 wound around the roller of the belt press is permeable to water or is designed such that it can absorb water in order to absorb the mechanical pressure occurring in the belt press 34 to absorb accumulating water and / or to let pass. In particular, air or water vapor can be used as the drying fluid, it being possible to use air at ambient temperature or also hot air as the drying air.

In the case of a suction roll, the drying fluid is discharged from a drying fluid hood 44 at least through the permeable outer endless belt 42, which Nonwoven material web and the permeable inner endless belt 40 are sucked or guided into the suction roll.

In the case of a blow roll, the drying fluid from the blow roll is blown into the hood 44 at least through the permeable inner endless belt 40, the nonwoven web, and the permeable outer endless belt 42.

As shown, the belt press 34 can be provided, for example, with only two endless belts 40, 42 wrapping the roller 36. The nonwoven material web lying between these endless belts 40, 42 is in this case touched by the two endless belts 40, 42.

In principle, however, the belt press 34, in addition to the inner and outer endless belts 40, 42, may also be provided with at least one further endless belt wrapping the roller 36 over a certain wrap angle. In this case, at least one such further endless belt can be arranged, for example, between the outer endless belt 42 and the nonwoven material web. The endless belts 40, 42 wrapping the roller 36 of the belt press 34 preferably comprise at least one felt belt and / or at least one fabric belt. In this case, in particular as the roller 36 of the belt press 34 looping inner endless belt 40 may be provided a felt belt. If the nonwoven material web in the belt press 34 is additionally additionally acted upon by a drying fluid, then at least one felt belt is provided behind the nonwoven material web at least in the direction of flow of the drying fluid.

In particular, in the case that the nonwoven material web in the belt press 34, which is preferred, in addition to a drying fluid is applied, all, as already mentioned, are wound around the roller 36 of the belt press 34 Endless belts 40, 42 designed to be permeable or permeable to the drying fluid.

As an outer endless belt 42 of the belt press 34, for example, an at least substantially smooth belt, in particular smooth forming belt, can be used.

In certain cases, it is advantageous if at least one of the nonwoven material web contacting endless belt 40, 42 of the belt press 34 is designed as a structured band, by which the nonwoven material web is structured and / or perforated accordingly.

According to an expedient embodiment of the present invention, the endless belts 40, 42 wrapping the roller 36 of the belt press 34, in particular in the direction of flow of the drying fluid, comprise a permeable endless belt, an endless smooth forming fabric, an endless fabric belt and an endless felt belt. In principle, however, fewer or more endless belts and / or the endless belts may be provided in a different order than the one just mentioned.

If the roller 36 of the belt press 34 is designed as a suction roller, the belts wrapping the roller 36 preferably comprise, viewed in the direction of flow of the drying fluid

a) a permeable press belt stretched around the roller 36, a permeable fabric belt and a permeable felt belt, or

b) a permeable press belt stretched around the roll 36, a permeable wire belt, a permeable fabric belt and a permeable felt belt, or c) a permeable press belt stretched around the roll 36, a permeable felt belt, a permeable fabric belt and a permeable felt belt, or d) a permeable felt press belt stretched around the roller 36, a permeable fabric belt and a permeable felt belt.

On the other hand, if the roller 36 of the belt press 34 is designed as a blower roll, then the belts wrapping the roller 36 preferably comprise viewed in the direction of flow of the drying fluid

b) a permeable press belt stretched around the roller 36, a permeable screen belt, a permeable fabric belt and a permeable felt belt, or

c) a permeable press belt stretched around the roll 36, a permeable felt belt, a permeable fabric belt and a permeable felt belt, or

d) a permeable felt press belt stretched around the roller 36, a permeable fabric belt and a permeable felt belt

The endless belts 40, 42 of the belt press can in particular be wound around the roller 36 over the same wrap angle.

Downstream of the belt press 34, the nonwoven material web is passed through at least one thermal drying device 46, in particular a TAD or air drying unit or a flat bed furnace. In this case, the nonwoven material web can be dried in such a thermal drying device 46, in particular to the final dry content. In the former 28, the nonwoven fabric may advantageously be formed with a low consistency having a solids content of in particular 0.01 to 0.1% on a smooth forming fabric or a structured forming fabric which structurally and / or perforates the nonwoven fabric. For this purpose, in particular a so-called Schrägsiebformer or the like can be used. The fleece can also be structured and / or perforated at the same time by the optionally provided hydroentanglement device 32. Such a hydroentanglement device 32 is accordingly preferred, in particular in those cases in which the nonwoven or the nonwoven material web is additionally to be structured and / or perforated.

The furnish in the former 28 may be i) at least partially made from natural fibers, such as northern bleached kraft pulp (NBKP), hardwood pulp (LBKP), abaca fiber pulp, cotton or the like, ii) at least partially from man-made fibers, such as Viscous or the like, iii) at least partially made of synthetic fibers, in particular of polyester, polyamide or the like, iv) at least partially of mineral fibers, in particular glass fibers or the like, v) at least partly of carbon fibers and / or vi) of a mixture of any of the aforementioned substances.

Advantageously, the substance entry into the former 28 at least partially consists of fibers which are longer than 2 mm, preferably longer than 3 mm and particularly preferably longer than 4 mm. In particular, to produce a nonwoven web having a basis weight greater than 50 g / m ^2, preferably greater than 80 g / m ² and more preferably greater than 100 g / m ^2, the nonwoven material web before or after the belt press 34 be guided over a vacuum applied suction roll. In detail, the first exemplary embodiment of the inventively converted device 30 for the production of nonwovens shown in FIG. 2 again comprises a former 28, a hydroentangling device 32, a belt press 34 and a thermal drying device 46, which in the present case For example, it is a TAD or air drying unit. In the former 28, the nonwoven web is formed, for example, by the wet process with a low consistency on a forming fabric 48, which at the same time serves as a transfer belt for transferring the nonwoven fabric to the hydroentanglement device 32. As indicated at "50", the nonwoven fabric can be formed with an additional layer.

The web formed in the former 28 is transferred to the hydroentangling apparatus 32 in a closed loop by the forming wire 48.

The consolidated nonwoven web 52 is transferred from the hydroentanglement device 32, for example, in an open draw to the belt press 34, which is shown here with only two endless belts 40, 42 looped around the roller 36, for example. From this belt press 34, the nonwoven material web 52 is transferred, for example, in an open train to the thermal or TAD drying device 46.

Simultaneously with the mechanical pressurization of the nonwoven material web 52 by the belt press 34, a drying fluid is preferably pressed through the endless belts 40, 42 permeable in this case and through the nonwoven material web 52 by a corresponding pressure difference. In this case, the roller 36 has an open surface, wherein, as already mentioned, it can be designed in particular as a suction or as a blower roll. In the illustrated embodiment, the hood 44 intended for dispensing or receiving the drying fluid is arranged above the roller 36. As shown, the roller 36 may be associated with a scraper 62.

The hydroentanglement device 32 is not mandatory. However, it can be provided in particular in the case that the nonwoven material web 52 is additionally structured and / or perforated. Such structuring or perforation can take place, inter alia, via the hydroentanglement device 32. In addition, in particular, the belt press 34 may also be provided with at least one structural band structuring and / or perforating the nonwoven material web 52, which is accordingly wrapped around the roller 36 again.

FIG. 3 shows a schematic illustration of another exemplary embodiment of a belt press 34 of the device converted according to the invention. In the present case, the hood 44 is arranged above the roller 36 of the belt press 34 for dispensing or receiving the drying fluid. In addition, in the illustrated exemplary embodiment only an inner endless belt 40 and serving as a press belt 42 outer endless belt 42 is wound around the roller 36 of the belt press 34.

The loop of the inner endless belt 40 is arranged in the present case below the loop of serving as a press belt outer endless belt 42. The inner endless belt 40 may in particular be a felt belt again. The drying fluid flow is directed from top to bottom or from bottom to top, depending on whether the roller 36 is designed as a suction roll or as a blow roll. The nonwoven web of material to be dewaxed lies again between the inner endless belt 40 and the outer endless belt 42. As already mentioned, the additional loading of the nonwoven web with drying fluid is optional. It is particularly preferred when the

Nonwoven material web should be structured and / or perforated simultaneously.

Also in the present embodiment shown in FIG. 3, a scraper 62 associated with the roller 36 of the belt press 34 can be seen again. As can be seen in particular from Fig. 3, the respective endless belts 40, 42 are guided in the same wrap around the roller 36 of the belt press 34, wherein the wrap angle is expediently slightly larger than the suction or blowing zone 64 of the roller of the belt press 34.

LIST OF REFERENCES

10 conventional device

12 shaper

14 hydroentanglement device

16 intake manifold, suction box

18 drainage device

20 thermal drying device (TAD)

22 dipping bath

24 winding device

26 forming fabric

28 shaper

30 device

32 hydroentanglement device 34 belt press

36 roller

40 inner (endless) band

42 outer (endless) band

44 (drying) hood

46 thermal drying device (TAD)

48 forming fabric

50 additional shift

52 nonwoven material web

62 scrapers

64 suction or blowing zone

Claims

claims

Method for converting a device for producing a nonwoven comprising a former (28) for forming a fleece, suction tubes and / or suction boxes (16) for dewatering the nonwoven, and a drying device (46), comprising the following steps:

Removing all upstream of the drying device (46) arranged suction pipes and / or suction boxes (16) and

Installing a belt press (34) between the former (28) and the dryer (46), the belt press (34) including a roller (36) around the at least one inner band (40) adjacent the roller (36) outer nonwoven web (52) can be arranged at least in the region of the roller (36) between the inner band (40) and the outer band (42) and is preferably arranged, and, wherein the press belt (42) with a belt tension of at least 15 kN / m to the roller (36) is pressed and preferably pressed.

Method according to claim 1,

characterized in that the roller (36) of the belt press (34) is designed for dispensing or receiving drying fluid having an open surface and the belts (40, 42) of the belt press (34) as against drying fluid and preferably against air and / or water vapor permeable belts (40, 42) are formed so that simultaneously with the pressing of the nonwoven material web (52) against the roller (36) by a pressure difference between the roller (36) and the outer Press belt (42) a drying fluid through the permeable strips (40, 42) and the nonwoven material web (52) can be flowed.

Method according to claim 2,

characterized in that the roller (36) of the belt press (34) is designed as a suction roll so that the drying fluid from preferably a drying fluid hood (44) at least by the permeable outer press belt (42), the nonwoven material web (52) and the permeable inner band (40) can be sucked into the suction roll.

Method according to claim 2,

characterized in that the roller (36) of the belt press (34) is designed as a blow roller so that the drying fluid from the blow roller at least through the permeable inner band (40), the nonwoven material web (52) and the permeable outer press belt ( 42) can preferably be blown to a hood (44).

Method according to at least one of the preceding claims,

characterized in that between the former (28) and the belt press (34) is arranged a device (32) for solidifying the formed web to a nonwoven material web.

Method according to claim 5,

characterized in that the device (32) is a mechanical hardening device and preferably a water jet hardening device (32). Method according to at least one of the preceding claims,

in that the nonwoven material web (52) is transferred in a closed train from the former (28) to the belt press (34) and preferably to the drying device (46).

8. The method according to at least one of the preceding claims,

in that at least one thermal drying device (46), preferably a TAD ("through air drying") or air drying unit or a flat bed oven, is provided downstream of the belt press (34).

9. A method for operating a device converted according to a method according to one of the preceding claims for producing a nonwoven fabric, which comprises the following steps:

Forming a web in the former (28),

further dewatering of the web of nonwoven material (52) resulting from the web, wherein the further dewatering of the nonwoven web (52) comprises the dewatering in the belt press (34), wherein the web material web (52) at least in the region of the roller (36 ) between the inner band (40) and the outer press belt (42) and pressed the press belt (42) with a belt tension of at least 15 kN / m to the roller (36) and thereby the nonwoven material web (52) and the inner band (40) against the roller (36) are pressed, and

Passing the nonwoven web (52) through the dryer (46) to bring the nonwoven web (52) to the final dry content.

10. The method according to claim 9,

in that the roller (36) of the belt press (34) is designed to discharge or receive drying fluid having an open surface and as belts (40, 42) of the belt press (34) to drying fluid and preferably to air and / or

Steam permeable belts (40, 42) are used and simultaneously with the pressing of the nonwoven web (52) against the roller (36) a drying fluid through the permeable belts (40, 42) and the

Nonwoven material web (52) is pressed, preferably by generating a corresponding pressure difference between the roller (36) and the outer press belt (42).

Method according to claim 9 or 10,

characterized in that the outer press belt (42) with a belt tension of 20 to 100 kN / m, preferably from 25 to 75 kN / m and particularly preferably from 40 to 50 kN / m to the roller (36) of the belt press (34) is pressed.

Method according to at least one of claims 9 to 11,

Thereby, a mechanical pressure of less than 140 kPa, preferably of less than 100 kPa and particularly preferably of less than 90 kPa, is exerted on the nonwoven material web (52) in the belt press (34).

Method according to at least one of claims 9 to 12,

characterized in that the nonwoven material web (52) is dewatered in the belt press (34) by at least 20%, preferably by 30 to 75% and more preferably by 33 to 50%.

14. The method according to any one of claims 9 to 13,

Thereby, the nonwoven material web (52) between the belt press (34) and the thermal drying device (46) is passed through an additional dewatering press.

15. The method according to at least one of claims 9 to 14,

Thereby, after the formation thereof in the former (28) and before further dewatering in the belt press (34), the formed web is consolidated by a consolidation process which preferably comprises mechanical consolidation and / or hydroentanglement.