EP2550394A1

EP2550394A1 - Method and device for cleaning papermaking-machine fabrics which are to be recycled

Info

Publication number: EP2550394A1
Application number: EP11710471A
Authority: EP
Inventors: Torsten Kallweit; Matthias Schmitt
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2010-03-24
Filing date: 2011-03-21
Publication date: 2013-01-30
Also published as: DE102010003196A1; WO2011117176A1

Abstract

A method for cleaning structural material which is to be recycled and is obtained from paper making-machine fabrics, in particular forming fabrics or press fabrics, comprises the following measures: a) comminution of a papermaking-machine fabric (B) in order to obtain fabric-material particles and detaching in the process of particulate contaminating material from the papermaking-machine fabric and/or the fabric-material particles (S1), b) separating of the fabric-material particles from the particulate contaminating material (S2), c) during or after execution of measure b), detaching of contaminating material which adheres to the surface of the fabric-material particles obtained during measure b) by frictional cleaning (S3, S4), d) during or after execution of measure c), separating of the fabric-material particles from the contaminating material which is detached from the surface of the fabric-material particles (S4).

Description

Method and apparatus for cleaning recycled paper machine clothing

description

The present invention relates to a method by which paper machine clothing can be used after the end of its useful life in a reprocessing cycle in order to be able to provide from the building material of the same starting material, for example for new paper machine clothing. In particular, the present invention relates to a method by which papermachine clothing of contaminants accumulating therein in the papermaking process can be separated to provide high quality feedstock in the recycle cycle. The present invention further relates to a device for providing rebuilding material of a papermachine fabric with which, for example, a previously explained method can be carried out. During the service life of papermachine clothing, these are also cleaned in the course of paper production in the paper machines in order to avoid excessive contamination of the clothing. Such impurities may affect the quality of the paper produced due to the effect on the dewatering properties of the fabrics, on the one hand, and because of the creation of marking effects. To clean the paper machine clothing therefore generally mechanical or abrasive working procedures are used in which, for example, with scrapers, brushes and high-pressure water jets or even with the use of dry ice impurities are removed from the paper machine clothing.

After the end of the service life and the return of the Building material of paper machine clothing in the production cycle of new paper machine clothing, it is necessary to remove the remaining in the clothing and there partly strong adhering impurities. The procedures known from the cleaning of papermachine clothing in paper machines themselves can in principle be used for this purpose. Since they are generally using substances such. As water or dry ice, but they lead to relatively complex purification procedures in the context of reprocessing, resulting in a considerable cost factor.

It is the object of the present invention to provide a method and a device for cleaning of reprocessing papermachine clothing, with which in a simple and cost-effective manner of impurities substantially free building material is obtained.

According to the invention, this object is achieved by a method for cleaning paper machine clothing, in particular forming fabrics, dryer fabrics, belts or press felts, recovered, reprocessed building material, comprising the measures:

a) crushing a papermachine fabric to obtain string material particles, thereby detaching particulate contaminant material from the papermachine fabric and / or the string material particles,

b) separating the string material particles from the particulate soil material,

c) during or after execution of the measure b), detachment of contamination material adhering to the surface of the covering material particles obtained in the measure b) by friction cleaning, d) upon or after execution of the measure c), separating the string material particles from the contaminant material detached from the surface of the string material particles. The inventive method is characterized primarily by the fact that it is dry, ie without addition of z. B. of water or dry ice. The removal or detachment of contaminant material from the clothing material particles obtained in the first process stage or the clothing itself is essentially mechanical. In this process, in those process steps in which larger impurity particles are removed for coarse cleaning and the surface of the covering material particles wetting or covering impurities are removed and removed, the fabric or the covering material particles are moved against one another or against surfaces of other bodies. The occurring shear forces or abrasive forces contribute to an efficient cleaning of the covering material particles. The subsequent separation of liquid on the one hand and cleaned string material particles on the other hand is therefore not required. The fabric particles obtained from the cleaning procedure can thus be entered directly into the reprocessing cycle. A drying or treatment of the separated contaminant is not required.

If in the measure a) a cutting mill is used to cut the paper machine clothing or larger segments thereof to obtain the string material particles, in particular by the action of the cutting knife, the detachment of coarser impurity particles is supported. For example, it may be provided that, when the measure a) is carried out, particles of covering material are produced essentially with a predetermined particle size, wherein preferably the predetermined particle size in a range of 2 to 30 mm, preferably 10 mm. It has been found that when shredding paper machine clothing, for example by means of a granulator, the fabric particles thus obtained have a size which, even distributed over the plurality of particles, will not deviate too much from the predetermined particle size. That is, the size distribution is comparatively low. Nevertheless, it has been shown that the larger contaminant material particles still present in the paper machine clothing originate from this comminution process with a distinctly smaller particle size, so that, on the other hand, in the following an efficient manner, owing to the clear size differences on the one hand and the generally available mass or density differences on the other hand Separation of the covering material particles can be carried out by the particulate impurities.

In particular, provision may be made for the measure b) to comprise sieving and / or sifting to separate the string material particles from the particulate contaminant material. Regardless of which of the procedures for separating these two above-mentioned particle fractions is used, the mentioned differences in particle size or mass and density come so clearly into play that the particle material obtained after this separation stage practically only string material particles, but no particulate contamination material more contains.

The measure c), that is to say the friction cleaning procedure to be regarded as a fine cleaning, may preferably comprise the movement of the string material particles relative to one another. The fabric particles themselves thus act as abrasive material and remove the contaminant adhering to the surface of other fabric particles. Since this process is generally in Of course, if there is a closed volume, and there may also be assemblies therein that set the string material particles in motion, they naturally also come in contact with the volume limiting surfaces of motion inducing assemblies, which also contributes to the removal of contaminants from the string material particle surface ,

Contaminants adhering to the surface of the string material particles include, among others, impurities called "stickies" which often have a resinous character and are composed of materials contained in the pulp used in the papermaking process and attached to the surface of the pulp In order to assist the detachment of these partly sticky or strongly adhering impurities, it may occasionally be necessary for the fabric particles to be brought into contact with the extractant when performing the measure c) Such a means of extraction can, of course, be used depending on the impurities present In this context, it should be pointed out that the use of such an extractant dera rt takes place, that only so much is entered that the surfaces of the covering material particles are coated or wetted, but in principle no dispersion containing the covering material particles is formed. In this respect, even with the use of such an extraction agent, it is still possible to speak of a basically dry cleaning process. As a rule, can be dispensed with the addition of an extractant.

The measure d) can also be carried out in such a way that it involves sieving and / or sifting to separate the string material particles from the contaminant material detached therefrom. Here it is to be borne in mind that the contaminants or contaminant particles released from the covering material particle surface will have a significantly smaller size and therefore also mass than the material particles themselves, for example also in powder or lubricant dusty consistency and thus more efficient both by sieving and by sifting Can be separated from the string material particles. Both the sieving and the sifting itself continue to set the string material particles in motion so that the contaminants that are released, but possibly re-attached to the surface, can be efficiently separated from the particles of the string material. As stated above, the contaminant material adhering to the surface of the string material particles may have a resinous, sticky character. In order to prevent that in the Friktionsreinigungsstufe by the energy input excessive heating of the fabric particles leads to a smearing of these impurities on the surface, it is proposed that when performing the measure c) and / or the measure d) the Bespannungsmaterialpartikel in the range of a predetermined temperature , preferably at about 25 to 30 ° C, are kept. According to a further aspect, the present invention relates to a method for reprocessing the building material of paper machine clothing, preferably forming fabrics or press felts, comprising the measures:

A) carrying out a cleaning method according to the invention, as explained above, in order to obtain substantially cleaned string material particles, B) Granulating the obtained in the measure A) covering material particles to obtain a granulate.

Since the covering material particles obtained from the cleaning procedure are already largely separated from impurities and no separation of liquids or the like used in the cleaning procedure is required, especially when the covering material particles or the papermachine fabric shredded to obtain the same are constructed from a single basic material or can be used ., were without further procedural measures, the procedure for granulating and thus to obtain a usable, for example, to build new paper machine clothing granules can be initiated.

If the paper machine clothing used as starting material z. B. be constructed with threads of different base materials, it is further proposed that after performing the measure A) and before the implementation of the measure B), the substantially purified string material particles are separated into particle fractions of different base material. It can thus be ensured that the granules contained after the granulation procedure are not composed of mixed materials, but of the basic materials previously used in different threads. For example, it can be provided that the measure B) a

Extrusion process, preferably with filtration of the extrusion material comprises.

According to a further aspect, the object mentioned at the outset is achieved by a device for providing rebuilding material of a paper machine clothing to be reprocessed, in particular for carrying out a method according to the invention, comprising one A crushing section for crushing a paper machine cloth, a friction cleaning section for releasing contaminants from string material particles, a separation section for separating the string material particles from contaminant material detached in the crushing section and / or the friction cleaning section thereof.

On the one hand in the crushing section as complete as possible digestion of the reprocessed paper machine clothing, z. B. to achieve a substantially complete rupture of a fabric structure, on the other hand, however, to achieve a defined crushing of the digested material covering, it is further proposed that the crushing section, a pre-shredding unit and subsequently a

Main crushing unit includes. It has been found that it is particularly advantageous if the pre-shredding unit comprises a single-shaft shredder or the main shredding unit comprises a cutting mill.

In order to pre-separate the comminuted material provided in the crushing section, which includes both string particle material and particulate contaminant material, before passing it into the friction cleaning section, it may further be provided that between the crushing section and the friction cleaning section there is a pre-separation unit for separating string material particles is provided by in the crushing section thereof detached contaminant material. Here, the use of a gravitational separator has proved to be particularly advantageous.

In a particularly advantageous variant, it is proposed that the friction cleaning section provide the separation section. This means a functional fusion, which makes the construction of the device cheaper and easier. For example, it may be provided that the friction cleaning section comprises a screening unit, preferably a tumble screen unit, with at least one, preferably at least two, screen layers. It has been shown that the use of such a tumbler sieve unit, in particular when at least one sieve layer is assigned to a brush arrangement, on the one hand leads to a very good friction cleaning result, on the other hand, the separation of the dissolved contaminants from the fabric particles contributes to an efficient cleaning.

It can further be provided that the separation section following the friction cleaning section comprises a post-purification unit. Thus, a very pure reprocessing material is obtained, which can be fed to the further reprocessing process, for example granulating, without any further processing.

The post-cleaning unit may comprise, for example, a dry-cleaning cylinder. The present invention will be explained below in detail with reference to the accompanying drawings. It shows:

1 shows a schematic representation of the process steps occurring in a cleaning process or a recycling process for a papermachine clothing;

2 shows an illustration of a device with which the method explained with reference to FIG. 1 can be carried out. In FIG. 1, at the start of the procedure represented by different process steps S, a papermachine fabric B to be reprocessed after removal from a paper machine is provided. ever for use in the paper machine, so for example as a forming fabric, dryer fabric, belt or press felt, this fabric B may be formed as a fabric or as a composite of a fabric or other support structure with a fleece or felt-like material. Also so-called spiral screens are used in paper machines as a covering and can be recycled in the manner described below.

As a building material of such paper machine clothing B generally polymer materials, such as. As PPS (polyphenylene sulfide) in the case of a spiral wire or PA (polyamide) in the case of a press felt used.

The paper machine clothing P provided for the comminution in process stage S1 can first be cut into individual pieces in order to be able to comminute them successively in a granulator or at the same time also in several granulators. In this case, the device used for comminution, so for example granulator, be set to a predetermined desired particle size, which may for example be in the range between 2 and 10 mm. Cutting mills provide after cutting a cut particulate material, which has only a relatively small mean deviation from the predetermined particle size.

When performing step S1, that is, when shredding the paper machine clothing B, not only are their filamentary or nonwoven or spiral-like constituents comminuted in fabric particles having the desired particle size, but also larger or particulate contaminants still present in the papermachine clothing are released. This is due to the fact that acting on the paper machine clothing B and by moving individual parts of the paper machine clothing B against each other forces by the action of the cutting blade, which dissolve the only relatively weakly adhering particulate impurities. Since the particulate impurities have a comparatively porous, friable consistency, they are due to this mechanical action by the cutting blade and the impact, frictional and shear stress in a crushing chamber not only detached from the Bespannungsmaterialpartikeln or the fabric B, but also comminuted. The result of this is that the particle material thus obtained contains stringing material particles which essentially have a particle size in the predetermined size range, as well as particle-like contaminant material whose particle size is generally below the particle size of the stringing material particles.

In a subsequent stage S2 of the process, these two particle fractions, ie the string material particles on the one hand and the particle-like contaminants present at least partially in dusty configuration, on the other hand, are separated from one another. Various procedures can be used for this purpose. On the one hand, it is possible by sieving, e.g. by means of a tumble screen with brushes, to separate the fractions, wherein the sieve opening size is selected so that the string material particles are retained, but the particulate impurities fall through the sieve. Also by sifting, in particular air classification, by exploiting the different particle sizes and the resulting different masses of particles on the one hand, and by exploiting the different densities of the building material of the covering material particles on the one hand and the particulate impurities on the other hand, these two particle fractions can be separated with very high selectivity.

The covering material particles obtained after this separation step S2 generally still have theirs Surface adhering impurities. These form a film-like dirt coating or comparatively strongly adhering deposits. These impurity materials generally consist of resinous or sticky substances contained in paper production in the pulp used to make the paper and coming into contact with the fabrics and accumulate on a fabric B over the service life. Since these relatively strongly adhering contaminant materials in the first process stage S1, so when crushing and the effects occurring on the surface of the string material particles, not or only partially can be removed, are already separated from the coarser, particulate impurities in the process step S3

Covered material particles subjected to a Friktionsreibungsprozess. It is moved by strong movement of the string material particles against each other and also against surfaces of a material containing the Bespannungsmaterialpartikel chamber or a movable agitator in the chamber moves and thus produce a the first still adhering contaminant detaching abrasive effect. This effect can be further supported by the fact that additional abrasive body, such. As scouring balls or the like, are entered. Since these comparatively strongly adhering impurities have a resinous or sticky character, it is furthermore possible to add an extractant. This extractant forms a solvent for these adhered contaminant materials and thus aids in the release from the surface of the fabric particles. In this case, the extractant is added only to such an extent that no dispersion of the clothing material particles is formed in a liquid, but a wetting of the surfaces of the same arises, as is still working so essentially dry.

The friction cleaning step S3 can be carried out using various per se Known devices take place, which are used to generate by energy input and mutual movement of particles abrasive effect on the surface. Such devices are used, for example, in the food industry to rid of cereal grains, rice grains, peas, lentils, dried beans, pepper, millet and the like of shells. They are known as so-called brushing, peeling, rubbing, grinding or polishing machines. Depending on the extent of the contamination or the impurities adhering to the surface of the covering material particles, it is also possible to use various of these devices in combination.

Other machines, such. As ringing drums, rotating drum screens, eddy current screening machines, vibrating screws or other screw systems based on two opposing and interlocking screw or blade rows can be used.

It is also possible to carry out the friction cleaning between two mutually moving surfaces, which load the fabric particles and ultimately work on the principle of a so-called fertilizer, as it is used in the pulping of cellulose fibers in paper production. If the process step S3, ie the friction cleaning, takes place in a suitable or intended for this process machine or a substantially closed chamber, it can be assumed that the detached from the surface of the stringing material particles contaminant material is in a fine, dusty configuration and, for example also due to electrostatic effect will re-attach to the surfaces of the string material particles, but no stronger adhesion effect will unfold more. To a separation of this Subsequently, in a separation stage S4, for example, again using a screening process or a visual process, a separation of the then substantially completely cleaned covering material particles from this contaminant material is achieved. In this separation process, in particular when it is carried out in a sifter, but in principle also when using a sieve, a further mechanical action is obtained on the surface of the clothing material particles, so that not only already separated contaminant materials are separated, but a further surface cleaning is achieved , Depending on the extent to which the papermaking fabric used for recycling was contaminated, it is basically also possible to use the separation stage S4, in which an abrasive action is also obtained on the fabric particles, as the sole friction friction stage with simultaneous separation of the fabric particles from the dissolved contaminants , This means that the stage S4 then not only provides the separation stage, but at the same time also forms the friction cleaning stage, so that the stage S3 which can be seen in FIG. 1 and serves exclusively for friction cleaning is not required.

Furthermore, it can be seen from the preceding illustration that a separate separation stage does not necessarily have to be provided after the crushing carried out in process stage S1. On the contrary, the particle-like or partly also dust-like material resulting from the comminution can be achieved directly in the friction cleaning process and in the separation of the covering material particles on the one hand from the contaminating materials or impurity particles on the other hand. This will be explained in more detail below with reference to FIG. 2. Due to the fact that during the comminution process, the particles of contaminant released from the covering material particles partly become powdery or dusty However, it is advantageous to achieve a separation of this already dissolved contaminant material before the friction cleaning process. The reason for this is that the efficiency of the friction cleaning process can be increased if less contaminant material, in particular also dusty contaminant material, is included in this process and thus essentially absorb only the string material particles with possibly also adhering impurities the energy used for the friction cleaning.

The separation stage S4 can be carried out with or without upstream Friktionsreinigungsstufe as already mentioned, preferably in a sifter. Here, for example, a so-called zigzag classifier, air classifier or cross class separator or plansifter can be used. Even in an eddy current screening machine, the string material particles can be separated from the dissolved impurities, due to the turbulence the particles collide against each other and against the chamber wall containing them and on the one hand, the release of impurities is supported, on the other hand, the separation and the discharge of substantially Impurity material and coarse material substantially provided by the cleaned string material particles. In the process stages serving the friction cleaning, that is to say in particular process stage S3, if necessary also process stage S4, the comparatively strong movement of the particle material, ie intensive energy input, generally causes heating of the particle material due to the frictional action which also occurs. This can, in particular if the impurities still adhering to its surface have a resinous character, lead to an increased smearing of these impurities over the surface of the surface Cover material particles lead, since by increasing the temperature, the viscosity of the adhering contaminant material decreases. In order to counteract this, it is advantageous if, when carrying out the method steps S3 or / and S4, it is ensured that an excessive temperature rise does not occur. In particular, a temperature level in the range of 25 to 30 ° C should be maintained, for example, by blowing appropriately tempered or cooled air.

After the process step S4 comprising the final separation of fabric particles of contaminant material, the fabric particles are generally in a form which can be used directly for granulation. In particular, there is no longer the risk that granules of inferior quality will be obtained by the introduction of impurities in the granulation process. However, there is the possibility that the initially fed papermaking fabric B was not constructed of a base material but, for example, has contained filaments or filaments of different base material. The mixing of such base materials during the granulation process is generally not desired. Rather, each base material or each particle fraction of a particular base material should be subjected by itself to the granulation process, to obtain correspondingly back a granulate from this base material. If this is necessary, after the end of the cleaning procedure with the separation stage S4 in a further separation stage S5, a separation of the fractions of the covering material particles different base material can be made. This separation can take place in various ways, preferably again taking advantage of the density differences of the various base materials. So here can be supported by the density separation centrifuging or a sifting be vorgenomnnen. A sieving assisted by partial agglomeration can also be used to separate the fractions of different Grundmatehals from one another, and then to separate them separately into the granulation process.

This granulation process takes place as the last process step S6. Here, for example, in an extrusion process using high-vacuum filtration or melt filtration, it can be ensured that the last contaminants still adhering to the surface of the covering material particles are removed. Of course, various extrusion filtration techniques may also be used in combination. For example, so-called filter cascades or self-cleaning melt filters with automatic scrapers can be used.

At the end of the granulation process granules of the desired grain size and with high-purity construction material are obtained, which can be supplied to the papermachine fabricating process, in particular to the production process of yarns used for the construction of papermachine clothing.

With the procedure according to the invention, it becomes possible to provide a very pure particulate starting material for a granulation process in a simple, because dry, but nevertheless reliable manner, this starting material being obtained from paper machine clothing which can no longer be used. The devices explained above, which can be used in the various process stages, are of course only to be understood as examples. It can also other equipment, such. B. a shredder or a single or multi-shaft shredder in process step S1 are used. Other types of classifiers, which by exploiting density and / or mass differences one Distribution into streams of different fractions can be used.

With reference to Fig. 2, a device, generally designated 10, will be described below, with which the above-explained method for cleaning paper machine coverings to be reprocessed can be carried out.

At the beginning of this device or the cleaning process is a hopper 12, in which a pre-cut into larger pieces paper machine clothing is entered. The pieces may be parts of paper machine clothing or whole papermachine clothing and are passed via a conveyor belt 14 to a guillotine 16. In this guillotine, these paper machine clothing pieces are comminuted by a cutting blade 18 provided therein. The guillotine 16 already forms part of a comminution section, generally designated 20.

Via a conveyor belt 22, the pieces of paper machine clothing to be reprocessed from the guillotine 20 are fed into a pre-shredding unit 24. This is formed in the example shown as a so-called single-shaft shredder 26. On the single shaft of this single-shaft shredder cutting blocks are mounted, for example, have four cutting edges and can be rotated with appropriate wear. Too frequent regrinding of the cutting edges can therefore be avoided. In particular, it is possible to completely replace the cutting blocks, if necessary. Through the rotating shaft of the single-shaft shredder 26, the pieces fed in from above via the conveyor belt 22 are drawn into a shredding space. In addition, the material to be shredded can be pressed into the cutting space by means of a movable slide. Should the shaft of the single-shaft shredder 26 get stuck, it can move into be moved in the opposite direction to drive them free. In addition, in this case, by opening a flap of the cutting space, access to this can be obtained to remove the shaft blocking pieces.

Under the shaft of the single-shaft shredder 26, a sieve is mounted. The shredded material falls through this screen onto another conveyor belt 28. Those components that are not yet so small that they can fall through the screen are returned to the cutting room and subjected to further reduction.

The conveyor belt 28 conveys the material delivered from the pre-shredding unit 24 which, for example, when the fabric to be reprocessed has a fabric structure, may still comprise at least parts of a fabric structure, to a main shredding unit 30. In the example shown, this is designed as a cutting mill 32. About the conveyor belt 28 conveyed pieces are entered from above into the granulator. They fall down into the cutting room of the granulator where the cutting shaft is located with knives thereupon.

With the granulator, the components of a paper machine clothing supplied to it are comminuted to a size in the range of about 1 cm to 3 cm. In order to ensure that only particles of this size or this size range are delivered, a sieve can also be provided at the lower region of the cutting mill, so that in fact only correspondingly comminuted material is dispensed.

The granulator 32, ie, the main crushing unit 30, constitutes the final system portion of the crushing section 20. From this crushing section 20, the particles produced therein are then conveyed further toward a generally 34 designated Friktionsreinigungssektion. It should be noted, however, that in the crushing process in the reprocessing paper machine clothing containing impurities are detached from this or the string material particles. By the crushing process, at least some of these impurity particles are very finely crushed or ground. Smaller particles can also be detached from the construction material of the paper machine clothing so that the entire comminution process can lead to an attack of very fine particulate material essentially provided by impurities. It may therefore be advantageous to effect a separation of these very fine, dust-like particles before they are introduced into the friction cleaning section 34. For this purpose, for example, a gravity separator, in particular a cyclone may be provided at the output of the cutting mill. This can be extracted together with the further processed particle material from the granulator 32, dust-like particles, so that already a pre-cleaning or pre-separation of the Friktionsreinigungssektion 34 to be supplied to the Bespannungspartikelmaterials is achieved. It has been found that this extraction of dust-like contamination is therefore particularly advantageous because it can significantly increase the efficiency of the subsequent friction cleaning process.

In the friction cleaning section 34, various process steps can be performed simultaneously. To make this possible, the friction cleaning section 34 may be constructed with a screen unit 36, preferably as a tumble screen unit 38. In this case, at least one, preferably several Sieblagen provided with decreasing from top to bottom Sieböffnungsgröße. The covering material particles are applied from the top of the top sieve and set in motion by brush moving on this sieve, preferably so-called triple nylon bristle strands. This move the Covering material particles on the screen and against each other. As a result of the resulting friction, adhering impurities are removed on the surface of the fabric particles. Furthermore, the movement of the brushes on the screen causes increased penetration of particles through the screen. This process can be repeated from top to bottom in several Sieblagen so that each screen a fraction of stringing material particles remains whose size does not allow passage through the openings of a respective sieve. In order to avoid clogging of the screen openings, balls constructed of rubber material can be arranged beneath each screen layer, for example. Due to the movement that takes place these rubber balls are set in motion and thus encounter from below against a respective Sieblage. This sieve openings clogging particles are released.

If z. B. two Sieblagen used, the upper sieve may have an opening size or mesh size of about 2 mm, while the lower sieve may have an opening size or mesh size of about 0.6 mm. Those particles passing through both the upper and lower layers of sieve are nearly 100% delaminated, generally dust-like contaminant particles. On the lower sieve layer, that is, the sieve layer formed with a smaller mesh size, a proportion of about 94% by weight of the covering material particles remains. About 2.7% by weight remains on the upper screen layer, which means that about 1.8% by weight of the input starting material is removed as contaminant material or loss material.

In an alternative embodiment, in which three stacked sieve layers are provided, a further sieve layer with an opening or mesh size of about 1.0 mm can be arranged between the two upper or lower sieve layers already explained above be provided. Here a finer graduation of the particles retained on the individual sieve layers takes place. It has been shown that with such adjustment of the mesh sizes again about 2.7 wt .-% remain on the upper Sieblage. This Bespannungsmatenalpartikel essentially have a length of at least 2 cm. On the middle wire layer, which has a mesh size of about 1 mm, remain string material particles having a size substantially of at least 1 cm. Their share is about 47 wt .-%. On the bottom wire layer also remains a share of about 47 wt .-%.

The friction cleaning section described above serves not only by the counter rubbing of the individual covering material particles to a detachment of impurities, but it also the Bespannungsmaterialpartikel be separated from the impurities detached therefrom. This means that the friction cleaning section 34 also simultaneously provides a separation section 40 here. In this friction cleaning / separation section, the particulate matter discharged from the crushing section 20, which may include both stringing material particles and impurities, may be subjected to both a separation process and the friction cleaning process. Depending on the mesh size, the various sieve layers hold back covering material particles, while the smaller or even dusty contamination particles can fall through. The retained string material particles are then agitated by the brushes acting on them and rub against each other, thereby releasing further contaminants from their surfaces. These detached, generally comparatively small contaminants can then pass through the screen openings again. Introduced into the friction cleaning section 34 or separation section 40 together with string material particles Impurity particles are immediately separated from the fabric particles by the wire screens. Subsequent contaminant particles that have been released during the friction cleaning process also move downward through the screen openings due to gravity and are thus separated from the fabric particles.

Further, due to the fact that the string material particles having the above-indicated size, that is, in a range of 1 cm to 3 cm fiber length, are preferably provided, the friction cleaning process can be performed very efficiently. The total surface on which the energy used for friction cleaning is distributed, is significantly smaller than in even further shredding the paper machine clothing.

Subsequent to the separation section 40 or friction cleaning section 34, the particulate material taken from the various screen layers, which essentially contains only string material particles, is subjected to a further purification process in a post-cleaning unit 41 in order to remove the last impurities. For this purpose, a dry cleaning cylinder 42 can be used. The covering material particles emerging from this can then be directed to a filling station 44, where they are packed, for example, in sacks and then supplied for further processing, for example granulation. Of course, it is also possible, instead of the filling station 44, to provide directly a device in which covering material particles are further processed, that is, for example, subjected to granulation.

Claims

claims

Process for the cleaning of construction material recovered from paper machine clothing, in particular forming fabrics, dryer fabrics, belts or press felts, comprising the measures:

a) shredding a papermachine fabric (B) to obtain fabric particles, thereby detaching particulate contaminant material from the papermachine fabric and / or the fabric particles (S1),

b) separating the string material particles from the particulate contaminant material (S2),

c) during or after execution of the measure b), detachment of contamination material adhering to the surface of the covering material particles obtained by the measure b) by friction cleaning (S3, S4), d) during or after execution of the measure c), separating the covering material particles from the contaminant material released from the surface of the string material particles (S4).

Method according to claim 1,

characterized in that the measure a) is carried out using a cutting mill.

Method according to claim 1 or 2,

characterized in that when carrying out the measure a) fabric material particles are generated substantially with a predetermined particle size, wherein preferably the predetermined particle size in a range of 2 to 30 mm, preferably 10 to 15 mm.

4. The method according to any one of claims 1 to 3,

characterized in that the measure b) comprises sieving and / or sifting to separate the string material particles from the particulate soil material.

5. The method according to any one of claims 1 to 4,

characterized in that when performing the measure c) the string material particles are moved against each other.

6. The method according to any one of claims 1 to 5,

characterized in that, when carrying out the measure c), the covering material particles are brought into contact with the extraction agent.

7. The method according to any one of claims 1 to 6,

characterized in that the measure d) comprises sieving and / or sifting to separate the string material particles from the contaminant material detached therefrom.

8. The method according to claim 7,

characterized in that when carrying out the measure c) and / or the measure d) the string material particles in the range of a predetermined temperature, preferably at about 25 to 30 ° C, are maintained.

9. A method for reprocessing the building material of paper machine clothing, preferably forming fabrics or press felts, comprising the measures: A) carrying out a method according to one of the preceding claims for obtaining substantially cleaned string material particles (S1 -S4),

B) granulating the covering material particles obtained in measure A) to obtain granules (S6).

Method according to claim 9,

characterized in that after carrying out the measure A) and before carrying out the measure B), the substantially cleaned string material particles are separated into particle fractions of different base material (S5).

Method according to claim 9 or 10,

characterized in that the measure B) comprises an extrusion process, preferably with filtration of the material to be extruded.

Apparatus for providing rebuilding material of a papermachine fabric, in particular for carrying out a method according to one of the preceding claims, comprising:

a crushing section (20) for crushing a

The paper machine clothing,

a friction cleaning section (34) for releasing contaminants from string material particles, a separation section (40) for separating the string material particles from contaminant material detached therefrom in the crushing section (20) or / and the friction cleaning section (34).

13. Device according to claim 12, characterized in that the comminution section (20) comprises a pre-shredding unit (24) and subsequently a main shredding unit (30).

Device according to claim 13,

characterized in that the pre-shredding unit (24) comprises a single-shaft shredder (26) or / and that the main shredding unit (30) comprises a cutting mill (32).

Device according to one of claims 12 to 14,

characterized in that between the crushing section (20) and the cleaning section (34) is provided a pre-separation unit for separating string material particles from contaminant material detached in the crushing section thereof.

Device according to claim 15,

characterized in that the pre-separation unit comprises a gravitational separator.

17. Device according to one of claims 12 to 16,

characterized in that the cleaning section (34) provides the separation section (40).

18. Device according to one of claims 12 to 17,

characterized in that the cleaning section (34) comprises a screening unit (36), preferably tumble screen unit, with at least one, preferably at least two, screen layers.

19. Device according to claim 18, characterized in that at least one sieve layer is associated with a brushing arrangement.

Device according to one of claims 12 to 19,

characterized in that the separation section (40) following the friction cleaning section (34) comprises a post-cleaning unit (41).

Device according to claim 20,

characterized in that the post-cleaning unit (41) comprises a dry-cleaning cylinder (42).