EP0464258B1 - Felt, in particular paper making felt, and method for making the same - Google Patents

Abstract

A felt, in particular a paper machine felt for the press section of a paper machine, has at least one carrier web and at least one fibre web applied thereto and joined thereto. To ensure that such a felt has improved running properties in spite of adequate transverse stability and can be manufactured at considerably lower costs, the carrier web(s) (45, 50, 57, 58, 64, 71, 72) is or are each formed from at least one carrier web strip (46, 51, 52, 59, 60, 65, 66, 73, 74, 75), whose width is less than that of the carrier web(s) (45, 50, 57, 58, 64, 71, 72) and which is or are helically wound continuously, essentially in the direction of running of the felt (42, 47, 53, 61, 67) at right angles thereto. The manufacture is carried out in principle by the following process steps: a) initially, a web of material is produced; b) at least one carrier web strip (46, 51, 52, 59, 60, 65, 66, 73, 74, 75), whose width is less than that of the finished felt (42, 47, 53, 61, 67), is fixed to the web of material; c) the web of material is moved in the peripheral direction; d) the build-up of the first carrier web (45, 50, 57, 58, 64, 71, 72) and, if appropriate, further carrier webs (45, 50, 57, 58, 64, 71, 72) takes place by means of a relative motion between the particular carrier web strip (46, 51, 52, 59, 60, 65, 66, 73, 74, 75) and the part (41), already built up, of the felt (42, 47, 53, 61, 67), helically at right angles to the direction of revolution of the web of material; e) each carrier web (45, 50, 57, 58, 64, 71, 72) is joined to at least one fibre web (43, 44, 48, 49, 54, 55, 56, 57, 62, 63, 68, 69, 79). <IMAGE>

Description

The invention relates to a felt, in particular paper machine felt, primarily for the press section of a paper machine, with at least one carrier web having one or more layers, which gives the felt structural strength, and at least one fiber web applied and connected to it, the structure of which depends on the carrier web or the carrier tracks is different. It also relates to a method for producing such an endless felt. Such felts are primarily used to transport thin webs through devices for producing the same, a main area of application being the production of paper in paper machines.

The known felts have at least one carrier web and at least one fiber web applied thereon. The carrier web - it can also be a plurality of carrier webs arranged one above the other with fiber webs lying between them - is designed in such a way that it gives the felt the structural strength in the longitudinal and transverse directions necessary for the intended purpose. It is therefore a matter of coherent webs, primarily fabrics being used. However, knitted fabrics, spunbonded nonwovens or bonded nonwoven fabrics reinforced in the transverse and longitudinal directions are also proposed.

A fibrous web is then placed at least on the surface of the carrier web and connected to the carrier web in order to achieve a smooth surface and damage to the items to be transported Avoid web, for example a paper web. In the press section of paper machines, the structure of such a felt is also based on the fact that the best possible drainage is achieved by the felt.

Such felts are still mainly produced in such a way that first the carrier web is produced in the width corresponding to the finished felt and only then is a fiber web extending over the full width placed on and connected to the carrier web. The connection is made primarily by needling, but also by gluing.

For the production of endless felts, also known as tubular felts, methods and devices are known in which a carrier web is first produced in the width corresponding to the width of the finished felt and is pulled onto two transport rollers arranged at a distance from one another and stretched between them. Then a fibrous web strip, the width of which is less than that of the finished felt, is fed to the carrier web and fastened to it. The carrier web is then moved in the circumferential direction, a relative movement being generated between the fiber web strip to be fed and the carrier web transversely to its direction of rotation. Because of this relative movement, the fibrous web strip progressively winds onto the carrier web transversely to the direction of rotation. A fibrous web is thus gradually built up, which can also be constructed in multiple layers. At the same time, needling and thus a connection between the fiber web and the carrier web is carried out in this device.

Two different concepts are known for generating the relative movement. In the device according to DE-B-23 24 985, DE-A-39 37 651, US-A-4 926 530̸ and DE-A-39 37 652, the feed device for the fibrous web strips is moved transversely to the transport rollers. The device according to DE-B-1 660̸765 and EP-B-0̸123,969 is used kinematically in reverse.

Here, the feed device is arranged in a stationary manner and the carrier web is accordingly shifted across on the transport rollers. For this purpose, grooves are worked into the transport rollers parallel to their longitudinal axes, in which grooves run, which are provided with needles projecting into the carrier web. It is conceivable, albeit complex, to combine the two principles.

In EP-B-0̸ 123 969 it is also pointed out that the device can also be used for treatment and processing measures, such as flaming, needles, brushes or the like. Threads running at a distance from one another can also be applied to the felt to form longitudinal drainage channels.

In addition, it is known from US-A-3 0̸97 413 to produce an endless tubular felt in that firstly, between two transport rollers, a layer of thread is made from one or more threads spaced apart and helically placed around the rollers, and then a fiber web is fed in the width corresponding to the finished felt, which was previously produced by cross-paneling a fiber web strip, and is needled with the carrier web. It is possible to use the transversely fed fibrous web strip to also feed a laid scrim of threads which extend parallel and at a distance therefrom and which then extend in the finished felt transversely to its circumferential direction. US-A-4 495 680̸ and US-A-4 594 756 are concerned with a device for producing the longitudinal thread structure known from US-A-3 0̸97 413, wherein the longitudinal thread structure can subsequently be needled with a fibrous web, either in the device itself or in a conventional needle machine.

The aim for felts constructed in this way was not to obtain any intersection points as are characteristic of fabrics, but rather only layers of thread extending primarily in the longitudinal direction. However, this had to be bought with the disadvantage that first a complete laid scrim had to be produced, whereby auxiliary measures had to be taken to stabilize the laid scrim for the subsequent needling process. For this purpose, either soluble foils were glued onto the scrim or the scrim was produced by producing a fabric with soluble cross threads, which were then removed after the needling process. The fibrous webs were also initially produced in the final width of the felt before they were needled with the laid scrim. Accordingly, the end width is limited by the width of the devices. Apart from this, the transverse stability of such felts is often not sufficient in view of the high loads, particularly in the press section of a paper machine.

For this reason, felts of the generic type are still produced with carrier webs as webs connected in the transverse and longitudinal direction, especially when the nonwoven web in the form of nonwoven web strips is applied continuously in the circumferential direction, but progressively in a helical manner in the transverse direction. This is shown by the just published DE-A-39 37 651 and DE-A-39 37 652. The disadvantage must be accepted that the carrier web must first be made in the width corresponding to the finished felt, which is done in correspondingly wide machines , for example weaving or knitting machines, happens. Since paper machine felts in particular have large widths, expensive and mostly slow-working weaving machines must be used for this. Knitting machines are only available in limited widths anyway, so that knitted fabrics have so far only been used with narrow felts. In addition, the machines must be set up accordingly for each paper machine felt, since paper machine felts are not series products. This results in high production costs and little flexibility. In addition, their in-house transport and their installation in devices in which the fiber web is applied is cumbersome and complex.

Another disadvantage of the generic felts is that they have a continuous structure in the transverse direction. As a result, defects such as seams or the like also extend across the entire width of the felt. Such felts are very sensitive to vibrations and cause corresponding malfunctions in the respective machine.

Irrespective of this, pure fiber felts are known which are built up by helically winding narrow fiber web strips (cf. GB-A-1 221 736, US-A-4 926 530̸). Since they have no carrier web, they have a low strength, which is based solely on the matting or intertwining of the fibers. Their use is therefore limited to very special cases with low loads.

The invention has for its object to design a paper machine felt of the type mentioned so that it has improved running properties despite sufficient transverse stability and can be produced at significantly lower costs.

• a) es wird zunächst eine Materialbahn hergestellt;
• b) an der Materialbahn wird wenigstens ein Trägerbahnstreifen befestigt, dessen Breite geringer ist als die des fertigen Filzes;
• c) die Materialbahn wird in Umfangsrichtung bewegt;
• d) der Aufbau der ersten Trägerbahn und gegebenenfalls weiterer Trägerbahnen erfolgt aufgrund einer Relativbewegung zwischen dem jeweiligen Trägerbahnstreifen und dem schon aufgebauten Teil des Filzes quer zur Umlaufrichtung der Materialbahn wendelförmig;
• e) der Aufbau der Trägerbahn (45, 64) bzw. wenigstens einer Trägerbahn (71) erfolgt in der Weise, daß sich jeweils teilweise überlappende Windungsabschnitte aus Trägerbahnstreifen (45, 65, 74) entstehen;
• f) jede Trägerbahn wird mit wenigstens einer Faserbahn verbunden.

This object is achieved in that the carrier web (s) is or are each formed from at least one carrier web strip, the width or width of which is smaller than the carrier web (s) and which is essentially in the running direction of the felt and helical is or are progressively wound transversely thereto, in each case partially overlapping winding sections of carrier web strips are present. Basically, the production takes place through the following process steps:

• a) a material web is first produced;
• b) at least one carrier web strip is attached to the material web, the width of which is less than that of the finished felt;
• c) the material web is moved in the circumferential direction;
• d) the construction of the first carrier web and possibly further carrier webs takes place helically due to a relative movement between the respective carrier web strip and the part of the felt already built up transversely to the direction of rotation of the material web;
• e) the construction of the carrier web (45, 64) or at least one carrier web (71) takes place in such a way that partially overlapping winding sections are formed from carrier web strips (45, 65, 74);
• f) each carrier web is connected to at least one fiber web.

In this way, according to the invention, a felt is provided for the first time in which the respective carrier web is composed of one or more carrier web strips which essentially extend in the running direction of the felt, but are wound in a helical manner. It has been found to be surprising that even such a carrier web - in comparison to thread lay - gives sufficient transverse stability. This obviously has to do with the fact that the carrier web strips themselves have their own transverse stability and partially overlapping winding sections. They therefore do not tend to move sideways or shift. On the other hand, the transverse stability is effectively supported by the fact that the fibrous web is connected to the carrier web strip, in particular needled. Correspondingly, this felt can also be used in the case of high loads, such as those which occur especially in the press section of a paper machine, without its dimensional stability being impaired in comparison with the generic felts.

This felt and in particular its manufacturing process have considerable advantages. Due to the winding process, possible defects in the carrier web strip are limited to its width and do not extend across the entire width of the felt. As a result, the excitation of vibrations is significantly reduced or even eliminated. This also makes it possible to place sections of carrier web strips with different properties one behind the other, because the resulting defects at the connections of the sections are locally limited to the width of the respective carrier web strip. This opens up a wide range of variations in terms of the carrier web structure. The permeability across the width of the felt can be varied according to the requirements. The chemical equipment can also be designed differently in order to create special properties at the required points on the felt.

In addition to the significantly improved properties and variation possibilities of the felt itself, there are still considerable advantages in the production of the same. A loom or knitting machine of a correspondingly small width is sufficient for producing the carrier web strip, regardless of the width of the finished felt. Such machines are not only inexpensive, they also work faster. In addition, for the first time the possibility is opened to produce very wide felts, such as those used in high-performance paper machines, with a carrier web from a knitted fabric. The carrier web strips can be produced in long lengths and thus without retrofitting the machines on supply rolls, which also results in a more economical and, moreover, more flexible production. The same applies, of course, to the production of carrier web strips from foils, spunbonded nonwovens or composite thread fabrics.

For the actual manufacturing process of the felt, the supply rolls are then called up accordingly and then a device such as is found in principle from the publications mentioned at the beginning (DE-B-23 24 985, DE-A-39 37 652, DE-B-1 660̸765, EP-B-0̸ 123 969) is known. The production of the felt composed of carrier web and fiber web can then take place in this device in one work step, which also contributes to the fact that the production costs are considerably lower compared to those of conventional felts. There are practically no limits to the width of the felt, ie very wide felts can be produced regardless of the width and structure of the respective carrier web strip. In addition, no special measures are required to set this width, since the manufacturing process is simply terminated when the end width of the felt is reached.

The basic idea of the present invention can be realized on the one hand by providing a carrier web with at least one layer in which the adjacent winding sections of carrier web strips partially overlap. Instead or in combination with this, however, a carrier web with several layers can also be present, with winding sections of carrier web strips of two adjacent layers only partially overlapping, that is to say they do not come to lie exactly above one another. The latter can also be achieved by winding a carrier web strip helically in one direction to form a layer and then helically in the other direction to form the next layer, so that the winding sections of carrier web strips intersect two adjacent layers.

In a further embodiment of the invention it is provided that the carrier web or at least one carrier web is formed in several layers from a plurality of carrier web strips which are wound one above the other. This makes it possible to give the individual layers of the carrier web different properties by using appropriate carrier web strips. If this is not necessary, the carrier web or at least one carrier web can be made of a carrier web strip may be formed, which is wound in several layers.

In a further embodiment of the invention it is provided that there is a carrier web with at least one layer in which the carrier web strip or at least one carrier web strip is wound helically in such a way that the longitudinal edges of the respective carrier web strip abut one another. At least one further carrier web strip of a carrier web can be wound helically in such a way that the adjacent winding sections of the respective carrier web strip partially overlap. Instead, a single carrier web strip can form at least one further layer in which the adjacent winding sections of the carrier web strip partially overlap.

The felt according to the invention can be constructed practically as desired. Several carrier webs can be provided, which are separated by a fiber web. The felt can also have a fiber web on both sides and also have multi-layer fiber webs.

According to a further feature of the invention, it is provided that the fibrous web or at least one fibrous web is formed from at least one fibrous web strip, the width of which is smaller than the felt and the or which progresses essentially in the running direction of the felt and in a spiral shape transversely thereto is or are wound. According to the invention, the fiber web or - in the case of several fiber webs - at least one fiber web - if not all - is constructed in the same way as the carrier web. This structure of the fiber web (s) has several advantages. On the one hand, the fiber web strip can be produced on a small machine of appropriate width and kept ready in the form of supply rolls. On the other hand, the subsequent production of the felt - if all fiber webs are built up accordingly - can be done in one machine and thus particularly done inexpensively.

It is expedient that the or at least one of the fibrous web strips from which a fibrous web adjacent to a carrier web is constructed is wound in a helical manner in such a way that the fibrous web strip is connected to two adjacent winding sections of the carrier web strip. This arrangement supports the cross stability of the felt. In the case of particularly high demands on the surface quality of the felt, it may be expedient for at least one fiber web forming one side of the felt to be continuous, i.e. is not made up of a fibrous web strip.

For the construction of the carrier web, the method according to the invention, which has already been shown in principle above, first requires the production of a material web to which the carrier web strip is attached and which can be moved in the circumferential direction. This material web can be designed differently depending on the desired structure of the felt. It is thus possible to first separately produce a fibrous web in the width of the finished felt, for example on a needle machine, and then to pull this fibrous web onto the device known in principle so that it can then be rotated in the direction of rotation. The - first - carrier web strip can then be attached to this fiber web. However, there is also the possibility that the material web is made as a material web strip with a width that is less than the width of the finished felt, and that the material web strip is removed again at the latest after the felt is finished. The carrier web strip - but also several - can then be attached to this material web strip at the beginning of the carrier web construction. The material web strip can be, for example, a waste or scrap product of any structure.

Alternatively, however, the material web can also be constructed in combination, namely from a material web strip, the Width is less than that of the finished felt, and from at least one fiber web strip attached to it, the width of which is also or is less than that of the finished felt. The fibrous web strip is or are constructed helically to form a fibrous web in that it is or are continuously fed transversely to the direction of rotation when there is relative movement between the fibrous web strip and the already built-up part of the fibrous web. In this case, the material web consists of a material web strip which is to be removed again after completion and of a fiber web strip which is built up to a fiber web by helical winding. The carrier web strip is then fastened to it for the purpose of building the carrier web, the fastening being able to take place with or directly to the connection of the fiber web strip to the material web strip or only after the fiber web has been completed. After removal of the material web strip, a felt consisting of a carrier web and an external fiber web is obtained in this way.

Moreover, as already mentioned, there is the possibility of providing additional fiber webs which are constructed from fiber web strips in the manner described in order to allow the production process to run in one device. Insofar as fiber web strips and carrier web strips run adjacent, they should be fed so that they are offset transversely to the direction of rotation such that the fiber web strip comes to lie over two adjacent carrier web strips. This supports the cross stability of the felt. The feed can also proceed in such a way that a multi-layer carrier web and / or a multi-layer fiber web are built up, either by feeding a plurality of carrier web strips and / or fiber web strips, or by a carrier web strip or fiber web strip through at least one-time reversal of the relative movement between carrier web strips or fiber web strips and already built-up part of the felt is wound over one another transversely to the direction of rotation.

In addition, the supply of carrier web strips and / or fibrous web strips can take place in such a way that the longitudinal edges come to lie against one another or that the adjacent winding sections of the fibrous web strips partially overlap. In the case of multi-layer designs of nonwoven webs and / or carrier webs, these two alternatives can also be combined with one another in terms of layers.

Of course, with corresponding requirements, there is also the possibility that at least one additional fiber web in the width of the finished felt is finished separately and then applied and fastened to the top and / or bottom of the built-up part of the felt. Likewise, several carrier webs can be built up by helically winding up carrier web strips, a fiber web being built up between the carrier webs by helically winding up the fibrous web strip.

A particularly effective connection, which hardly disturbs the structure of the felt, between the fiber web and the carrier web is produced in a manner known per se by needling, the needling being carried out in strips even during the construction of the carrier web and / or the fiber web, by the device used for this purpose a corresponding needle device is assigned.

Figur (1)

in schematischer Darstellung eine Seitenansicht und

Figur (2)

eine Draufsicht auf eine Vorrichtung zur Herstellung eines Filzes sowie

Figuren (3) bis (7)

verschiedene, schematisch im Querschnitt dargestellte Ausführungsformen von Filzen.

In the drawing, the invention is illustrated in more detail using exemplary embodiments. Show it:

Figure (1)

a schematic representation of a side view and

Figure (2)

a plan view of an apparatus for producing a felt and

Figures (3) to (7)

Various embodiments of felt, shown schematically in cross section.

The device (1) shown in Figures (1) and (2) has two transport rollers (2, 3) which have horizontal axes of rotation (4, 5) and are mounted at a horizontal distance from one another. The transport rollers (2, 3) have grooves which run parallel to the axes of rotation (4, 5) and are distributed over the lateral surfaces, for example with (6, 7) - in which transport chains - for example with (8, 9) - are guided . These carry needle pieces - designated by way of example with (10̸, 11) - which protrude beyond the lateral surfaces of the transport rollers (2, 3). The transport rollers (2, 3) rotate in the directions of arrows A.

The device (1) has two feed devices (12, 13). A total of four supply rolls (14, 15, 16, 17) are rotatably mounted in the upper feed device (12) in the direction of the arrows, namely two adjacent upper supply rolls (14, 15) and two lower supply rolls also arranged side by side ( 16, 17). Each supply roll (14, 15, 16, 17) has an axis of rotation (18, 19, 20̸, 21), on each of which a web strip (22, 23, 24, 25) is wound. Guide rollers (26, 27, 28) ensure perfect guidance of the unwound web strips (22, 23, 24, 25).

In addition to the supply rolls (14, 15, 16, 17), a carding device could also be provided, via which a nonwoven fabric can be fed.

The second feed device (13) is arranged on the underside of the device. In it two supply rolls (29, 30̸) are stored side by side, which also consist of the axes of rotation (31, 32) and the web strips (33, 34) wound on them. Guide rollers (35, 36) serve to support the unwound web strips (33, 34).

The device (1) also has a needle machine (37), of which only the nail boards (38, 39, 40̸) are shown here. The nail boards (38, 39, 40̸) are arranged one above the other and vertically movable. A needle board (38) is provided in the upper part of the device (1), while two counter-rotating needle boards (39, 40̸) are present in the lower part.

Depending on the desired structure of the felt to be produced on the device (1), fibrous web strips or carrier web strips can be used as web strips (22, 23, 24, 25, 33, 34). The fibrous web strips then consist of a nonwoven fabric, the nonwoven fabric having different fiber orientations, fineness and fiber density, while the carrier web strips can have different structures, for example woven, knitted, spunbonded nonwoven, film and / or composite thread laid strips.

At the beginning of the manufacturing process, a strip of material is first drawn onto the two transport rollers (2, 3), approximately at the level of the supply of the supply rolls (14, 15, 16, 17, 29, 30̸). This strip of material web can be, for example, a reject fabric strip. The individual web strips (22, 23, 24, 25, 33, 34) are then attached with their front ends. The two transport rollers (2, 3) and thus the material web strip are then set in motion in the circumferential direction, as a result of which the web strips (22, 23, 24, 25, 33, 34) are removed from the supply rolls (14, 15, 16, 17, 29, 30̸) are removed and come to rest on the material web strip. At the same time, the needle machine (37) is put into operation with the result that the individual web strips (22, 23, 24, 25, 33, 34) are needled together, ie the fibers of the fibrous web strips penetrate into the carrier web strips.

With the rotary movement of the transport rollers (2, 3), the transport chains (8, 9) are set in motion in the directions of the arrows B. The consequence of this is that the material web strip and thus also the part (41) of the felt already built on it are transported accordingly. Due to the relative movement between this part (41) of the felt and the web strips (22, 23, 24, 25, 33, 34), the latter are wound helically onto the transport rollers (2, 3) at a speed of the transport chains (8 , 9) corresponding slope.

This continues until the felt has reached its final width. The web strips (22, 23, 24, 25, 33, 34) are then cut off. The finished felt is drawn off from the transport rollers (2, 3) by putting the transport chains (8, 9) into operation again. After the felt has been removed, the material web strip, which is used only as an alternative, is cut off. The felt is then either finished or can be used for further processing operations, for example in order to needle a further fiber web, which has the width of the felt from the outset, in a needling machine.

Variations of the device (1) shown are of course conceivable. The individual supply rolls (14, 15, 16, 17, 29, 30̸) can also be offset from one another, so that the web strips (22, 23, 24, 25, 33, 34) are fed accordingly offset, which is particularly advantageous for the lateral stability. Also, not all supply rolls (14, 15, 16, 17, 29, 30,) have to be available. In addition, the distance between the transport rollers (2, 3) is variable so that felts of different lengths can also be produced.

In Figures (3) to (7) various embodiments of felts made on the device (1) are in cross-section, i.e. transversely to the intended running direction. In the exemplary embodiment shown in FIG. 3, the felt (42) has a lower fiber web (43) and an upper fiber web (44), a carrier web (45) being arranged between the two fiber webs (43, 44). The lower fibrous web (44) has been made conventionally, i.e. separately in the intended end width of the felt (42), and then needled onto the underside of the combination of fiber web (44) and carrier web (45) in a needle machine.

The fibrous web (44) and the carrier web (45) have been produced in the device (1) according to the figures (1) and (2). The speed of the transport chains (8, 9) has been set so low that the individual turns of the carrier web strip (46) partially overlap, which has been expressed schematically by the Z-shaped representation of the carrier web strip (46). The upper fibrous web (44) has a helical structure. Due to the needling, this fibrous web (44) has a largely homogeneous structure. Due to the needling of both the upper and the lower fiber webs (43, 44) with the carrier web (45), the individual turns of the carrier web strip (46) cannot move transversely with respect to one another. As a result and due to the inherent stability of the carrier web stiffener (46) in the transverse direction, the felt (42) has sufficient transverse stability.

The felt (47) shown in Figure (4) also has a lower and an upper fiber web (48, 49) which correspond to the fiber webs (43, 44) in the felt (42). The intermediate carrier web (50̸) is constructed here in two layers, in that two carrier web strips (51, 52) have been fed one above the other. This can have happened simultaneously or in succession. The speed of the transport chains (8, 9) has been set so high that the individual turns of the carrier web strips (51, 52) do not overlap, but rather adjoin their longitudinal edges. The carrier web strips (51, 52) have also been fed in such a way that they are offset from one another, that is to say the longitudinal edges of the turns of the lower carrier web strip (52) are offset from those of the upper carrier web strip (51). Adequate transverse stability is also achieved here by needling the fiber webs (48, 49) with the carrier web (50̸).

The felt (53) shown in FIG. (5) has three superimposed fiber webs (54, 55, 56), between each of which a carrier web is arranged. The lower fiber web (54) is conventionally produced and needled like the lower fiber webs (43, 48) of the felts (42, 47). The middle and upper fiber web (55, 56) have been built up in the device (1) according to the figures (1) and (2) by helically applying a fiber web strip. This also applies to the carrier webs (57, 58) which have been built up from carrier web strips (59, 60̸) by being introduced into the device (1) according to FIGS. (1) and (2). This was done in such a way that the longitudinal edges of the turns of the carrier tape strips (59, 60̸) lie against each other. The carrier web strips (59, 60̸) have been fed offset so that the longitudinal edges do not lie on top of each other. The individual layers of the felt (53) are connected to one another by needling the fiber webs (54, 55, 56) with the carrier webs (57, 58).

The felt (61) shown in Figure (6) has a lower fiber web (62) and an upper fiber web (63). The lower fiber web (62) was subsequently needled after separate production, while the upper fiber web (63) in the device (1) according to FIGS. (1) and (2) was built up by helically winding up a fiber web strip. A carrier web (64) is enclosed between the two fiber webs (62, 63) and has two layers. The lower layer of the carrier web (64) is formed by a carrier web strip (65) which has been wound up in the same way as the carrier web strip (46). The individual turns of the carrier web strip (65) thus overlap. The upper layer of the carrier web (64), on the other hand, is formed by a carrier web strip (66), the individual turns of which adjoin one another, that is to say lie next to one another and do not overlap. The two carrier web strips (65, 66) are offset from one another in such a way that their longitudinal edges do not lie one above the other.

The felt (67) shown in Figure (7) has a lower fiber web (68), a middle fiber web (69) and an upper fiber web (70̸). The lower fiber web (68) is conventionally and separately manufactured and then needled. The overlying part of the felt (67) has been built up in the device (1) according to the figures (1) and (2).

A carrier web (71, 72) is enclosed between the fiber webs (68, 69, 70̸). The lower carrier web (71) is formed from two carrier web strips (73, 74), the windings of the lower carrier web strip (73) lying next to one another, while the windings of the upper carrier web strip (74) overlap. The upper carrier web (72) is constructed from a carrier web strip (75) in such a way that its turns lie side by side without overlap. The individual layers are connected by needling the fiber webs (68, 69, 70̸).

Of course, the device (1) according to the figures (1) and (2) can also be used to produce felts of a different structure will. The respective lower fiber web in the device (1) can also be constructed from one or more fiber web strips. A plurality of carrier webs with overlapping turns can also be superimposed. In particular, if the felt is completely built up in the device (1) according to the figures (1) and (2), there are practically no limits to the width, ie extreme widths can also be produced for the previously wide devices for the production the carrier web (s) and fiber webs are not available, in particular if the carrier web (s) are designed as woven or knitted fabrics.

Claims (31)

1. A felt, particularly a papermaking machine felt for the pressing part of a papermaking machine, having at least one supporting length (45, 64, 71, 72) which comprises one or more layers and which imparts structural strength to the felt (42, 61, 67), and at least one fibrous length (43, 44, 62, 63, 68, 69, 70) which is applied to the supporting length and attached thereto, the structure of which fibrous length is different from that of the supporting length (45, 64) or supporting lengths (71, 72), characterised in that the supporting length(s) (45, 64, 71, 72) is or are each formed from at least one supporting length strip (46, 65, 66, 73, 74, 75), the width of which is less than that of the finished supporting length(s) (45, 64, 71, 72) and which is or are wound substantially in the direction of travel of the felt (42, 61, 67), as well as progressively helically transverse thereto, wherein winding sections are present which partially overlap in each case and which comprise supporting length strips (46, 65, 74).
2. A felt according to claim 1,
   characterised in that a supporting length (45, 64, 71) is present which has at least one layer in which the adjacent winding sections of supporting length strips (46, 65, 74) partially overlap.
3. A felt according to claim 1 or 2,
   characterised in that a supporting length (50, 64, 71) having a plurality of layers is present, wherein winding sections comprising supporting length strips (51, 52, 65, 66, 73, 74) of two adjacent layers overlap only partially.
4. A felt according to any one of claims 1 to 3,
   characterised in that a supporting length strip is wound helically in one direction to form one layer and then helically in the other direction to form the next layer.
5. A felt according to any one of claims 1 to 4,
   characterised in that the supporting length (50, 64) or at least one supporting length (71) is formed from a plurality of supporting length strips (51, 52, 65, 66, 73, 74) wound one above another.
6. A felt according to any one of claims 1 to 4,
   characterised in that the supporting length or at least one of the supporting lengths is formed from a supporting length strip which comprises multiple layers wound one above another.
7. A felt according to any one of claims 1 to 6,
   characterised in that a supporting length (50, 57, 58, 64, 71, 72) is present which has at least one layer, in which the supporting length strip (46) or at least one supporting length strip (51, 52, 66, 73, 75) is helically wound in such a way that the longitudinal edges of the respective supporting length strip (46, 51, 52, 66, 73, 75) adjoin each other.
8. A felt according to claim 7,
   characterised in that at least one further supporting length strip (65, 74) of a supporting length (64, 71) is wound helically in such a way that the winding sections of the respective supporting length strip (65, 74) which are disposed side by side partially overlap each other.
9. A felt according to claim 7,
   characterised in that the supporting length strip forms at least one further layer in which the adjacent winding sections of the supporting length strip partially overlap each other.
10. A felt according to any one of claims 1 to 9,
    characterised in that the felt (53, 67) comprises a plurality of supporting lengths (57, 58, 71, 72) which are separated by a fibrous length (55, 69).
11. A felt according to any one of claims 1 to 10,
    characterised in that the felt (42, 47, 53, 61, 67) has a fibrous length (43, 44, 48, 49, 54, 56, 68, 70) on both sides in each case.
12. A felt according to any one of claims 1 to 11,
    characterised in that the fibrous length or at least one fibrous length (44, 49, 55, 56, 63, 69, 70) is formed from at least one fibrous length strip, the width of which is less than the felt (42, 47, 53, 61, 67) and which is or are wound substantially in the direction of travel of the felt (42, 47, 53, 61, 67) and progressively helically transverse thereto.
13. A felt according to claim 12,
    characterised in that the or at least one fibrous length strip from which a fibrous length (44, 49, 55, 56, 63, 69, 70) adjacent to a supporting length is built up is helically wound in such a way that each fibrous length strip is joined to two adjacent winding sections of the supporting length strip (46, 51, 59, 60, 66, 74, 75).
14. A felt according to any one of claims 1 to 13,
    characterised in that at least one fibrous length (43, 48, 54, 62, 68) forming one side of the felt (42, 47, 53, 61, 67) is of continuous construction.
15. A felt according to any one of claims 1 to 14,
    characterised in that at least one fibrous length (43, 44, 48, 49, 54, 55, 56, 62, 63, 68, 69, 70) in each case is needle-bonded to the supporting length(s) (45, 50, 57, 58, 64, 71, 72).
16. A process for producing an endless felt (42, 61, 67), particularly a papermaking machine felt for the pressing part of a papermaking machine, which is built up from at least one supporting length (45, 64, 71, 72) which comprises one or more layers and which imparts structural strength to the felt (42, 61, 67), and in which at least one fibrous length (43, 44, 62, 63, 68, 69, 70) is applied to the supporting length (45, 64, 71, 72) and attached thereto, wherein the structure of the fibrous length (43, 44, 62, 63, 68, 69, 70) is different from that of the supporting length (45, 64) or supporting lengths (71, 72), characterised by the following process steps:

    a) a fabric length is first produced;

    b) at least one supporting length strip (46, 65, 66, 73, 74, 75) is fixed to the fabric length, the width of which supporting length strip is less than that of the finished felt (42, 61, 67);

    c) the fabric length is moved in the direction of circulation;

    d) build-up of the first supporting length (45, 64, 71, 72) and optionally of further supporting lengths (45, 64, 71, 72) is effected helically transverse to the direction of circulation of the fabric length, due to a relative movement between the respective supporting length strips (46, 60, 65, 66, 73, 74, 75) and the part (41) of the felt (42, 61, 67) which has already been built up;

    e) build-up of the supporting length (45, 64) or of at least one supporting length (71) is effected in such a way that winding sections which comprise supporting length strips (45, 65, 74) and which each partially overlap each other are formed;

    f) each supporting length (45, 64, 71, 72) is attached to at least one fibrous length (43, 44, 48, 49, 54, 55, 56, 57, 62, 63, 68, 69, 70).
17. A process according to claim 16
    characterised in that a supporting length (45, 64, 71) having at least one layer is built up in such a way that partially overlapping winding sections are formed from supporting length strips (46, 65, 74).
18. A process according to claim 16 or 17, characterised in that a supporting length (50, 64, 71) having a plurality of layers is built up in such a way that winding sections comprising supporting length strips (51, 52, 65, 66, 73, 74) of two adjacent layers only partially overlap.
19. A process according to any one of claims 16 to 18,
    characterised in that the fabric length is produced separately as a fibrous length having the width of the finished felt, before the - first - supporting length strip is fixed to it.
20. A process according to any one of claims 16 to 19,
    characterised in that the fabric length is fabricated as fabric length strips having a width which is less than the width of the finished felt (42, 47, 53, 61, 67), and that the fabric length strips are removed again after the completion of the felt (42, 47, 53, 61, 67) at the latest.
21. A process according to any one of claims 16 to 18,
    characterised in that the fabric length is composed of a fabric length strip, the width of which is less than that of the finished felt (42, 47, 53, 61, 67), and of at least one fibrous length strip fixed thereto, the width of which is likewise less than that of the finished felt (42, 47, 53, 61, 67), wherein the fibrous length strip(s) is or are built up helically to form a fibrous length (44, 48, 55, 56, 63, 69, 70) in that it or they are continuously fed transverse to the direction of circulation during a relative movement between the fibrous length strip and the part (41) of the fibrous length (44, 48, 55, 56, 63, 69, 70) which has already been built up, and that the or at least one supporting length strip (46, 51, 52, 59, 60, 65, 66, 73, 74, 75) is fixed to the fibrous length strip for the helical feed, and that the fabric length strip is finally removed again, after the completion of the felt (42, 47, 53, 61, 67) at the latest.
22. A process according to any one of claims 16 to 20,
    characterised in that the or at least one fibrous length (44, 49, 55, 56, 63, 69, 70) is built up helically in that at least one fibrous length strip is continuously fed in the direction of circulation at a width which is less than that of the finished felt (42, 47, 53, 61, 67), and that a relative movement is effected between the fibrous length strip or strips and the part (41) of the felt which has already been built up.
23. A process according to claim 21 or 22,
    characterised in that at least adjacent fibrous length strips and supporting length strips (46, 51, 52, 59, 60, 66, 73, 74, 75) are fed displaced in relation to each other transverse to the direction of circulation in such a way that each fibrous length strip is situated above two adjacent supporting length strips (46, 51, 59, 60, 66, 71, 75).
24. A process according to any one of claims 15 to 23,
    characterised in that a plurality of supporting length strips (51, 52, 65, 66, 73, 74) and/or fibrous length strips is fed in such a manner that a multilayer supporting length (50, 64, 71) or fibrous length is built up in each case.
25. A process according to any one of claims 15 to 24,
    characterised in that a multilayer supporting length or fibrous length is built up in that a supporting length strip or fibrous length strip is wound superimposed transverse to the direction of circulation, by at least one reversal of the relative movement between the supporting length strip or fibrous length strip and the part of the felt which has already been built up.
26. A process according to any one of claims 18 to 25,
    characterised in that at least one supporting length strip (51, 52, 59, 60, 66, 73, 75) and/or fibrous length strip is wound helically in such a way that the longitudinal edges adjoin each other in each case.
27. A process according to any one of claims 16 to 26,
    characterised in that the or at least one fibrous length strip is helically wound in such a way that the winding sections of the respective fibrous length strip (46, 65, 74) which are disposed side by side are situated partially overlapping each other.
28. A process according to claim 26 or 27,
    characterised in that the or at least one fibrous web length and/or supporting length (71) is helically wound in multiple layers in such a way that in at least one layer the longitudinal edges of the winding sections each adjoin each other and in at least one further layer the winding sections situated side by side partially overlap each other.
29. A process according to any one of claims 16 to 28,
    characterised in that in addition at least one further fibrous length (43, 48, 54, 62, 68) is produced separately with the width of the finished felt and is then applied and fixed to the upper and/or lower face of the built-up part (41) of the felt.
30. A process according to any one of claims 16 to 29,
    characterised in that a plurality of supporting lengths (57, 58, 71, 72) is built up by helically winding supporting length strips (59, 60, 73, 74, 75), and that a fibrous length (55, 69) is built up between the supporting lengths (57, 58, 71, 72) in each case by helically winding fibrous length strips.
31. A process according to any one of claims 16 to 30,
    characterised in that the fixation between supporting length(s) (45, 50, 57, 58, 64, 71, 72) and fibrous length(s) (43, 44, 48, 49, 54, 55, 56, 62, 63, 68, 69, 70) is effected by means of needle-bonding.

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