WO2019011362A1

WO2019011362A1 - Fabric, filter and use thereof

Info

Publication number: WO2019011362A1
Application number: PCT/DE2018/000208
Authority: WO
Inventors: Peter Wirtz; Markus KNEFEL; Daniel DRESCHERS; Dominik HERPER; Christoph LÄPPCHEN; Peter Henseler
Original assignee: Gkd - Gebr. Kufferath Ag
Priority date: 2017-07-10
Filing date: 2018-07-10
Publication date: 2019-01-17
Also published as: DE102017010756A1

Abstract

The invention relates to a fabric, a filter element, a filter and a use of such a fabric, such a filter element or such a filter, the warp comprises yarns having different diameters.

Description

Fabric, filter element, filter and use thereof

The invention relates to a fabric, a filter element, a filter and a use of such a fabric, such a filter element or such a filter. [02] In particular, the invention relates to fabrics which serve to give other filtration materials sufficient mechanical stability, preferably also in the deformed and / or folded state.

[03] The applications are in particular the filtration of liquids and in particular of hydraulic fluids. This raises the object that the tissue, in particular in the deformed and / or folded state, on the one hand a high flow ("drainage in a fold") should allow and on the other hand provide an even finer filter medium sufficient support surface available Fabric also made high stability requirements.

[04] Filter elements produced with such fabrics are used in particular in hydraulic systems, as used for example in self-propelled machines, for example construction machines or agricultural machines, or even in tooling and processing machines, for example injection molding machines. In this case, the hydraulic systems must meet very high demands on the cleanliness of the hydraulic fluid in order to be able to fulfill their function without disruption and with little wear over long periods of operation. The filter element is flowed through by the hydraulic fluid, wherein a pressure difference is established between the raw side and the clean side of the filter element. In order to withstand this pressure difference, the filter material is supported by a support structure. Depending on the mode of operation of the hydraulic system, the support structure is subject to a strong pressure swing load, which can result in damage to the support structure.

[05] Usually, a galvanized metal screen or a stainless steel mesh is used as support structure. However, in the case of volume flow changes, this

Confirm and sko drive from wire breaks. This can lead to contamination of the hydraulic fluid. It has therefore already been proposed to replace the metal mesh with a plastic fabric. However, it has been shown that the use of a plastic fabric or even of an extruded plastic mesh grid can lead to static charges, which can result in impairment of the hydraulic system, in particular damage to the hydraulic fluid.

[06] Such fabrics are described for example in EP 1436062 A I. However, with prolonged use, the tissue layers can press against each other in such a way that the flow of liquid is impaired. This is the case in particular if, for example in the case of a folded fabric, tissue layers abut one another directly or with filter material lying therebetween.

[07] The object of the present invention is therefore to propose a fabric, a filter element and a filter, and a use thereof, which also ensure a good flow through when tissue areas are pressed against one another.

[08] This object is achieved with a fabric having the features of patent claim 1. An inventive filter element is the subject matter of claims 8 to 13, a filter element is the subject of claim 14 and claims 15 and 16 describe advantageous uses. Advantageous further developments are the subject of the dependent claims.

[09] It is known to use different diameters for the plastic threads of the warp and for the metal threads in the weft. With regard to the flow characteristics, however, it has been found that it is particularly advantageous if the chain has threads with different diameters. Thereby, a support and a spaced arrangement of such tissues or such a fabric and a filter material can be achieved.

[10] Experiments have shown that it is advantageous if the chain has a plurality of smaller diameter threads between larger diameter threads. [1 1] In this case, the chain between threads with a larger diameter each have more than one thread, in particular two to five threads with a smaller diameter.

[12] It is advantageous if the chain between threads with a larger diameter each having one or more threads with a smaller diameter.

It is particularly advantageous if the shot has a share of more than 20% of threads made of plastic.

A particularly simple construction of the fabric is achieved when the threads in the shot predominantly have the same diameter. In particular, all threads in the weft may have the same diameter.

For example, for the filtration of liquids, in particular hydraulic fluids, tissues are particularly suitable whose filaments have a diameter in the range between 50 μπι and 500 μηι.

[16] Such fabrics can be used alone or together with filter materials. Therefore, an object of the invention is a filter element comprising such a fabric.

[17] This filter element can also have a plurality of such fabric stacked one above the other.

It is advantageous if the stacked fabrics are stacked such that the threads are arranged offset from each other with a larger diameter.

[19] A particularly advantageous embodiment provides that the filter element has a zigzag-folded fabric. On such a zigzag folded fabric, a filter material can be arranged, which is made for example of a nonwoven material. A simple construction of a filter element provides that the zigzag folded tissue is arranged as a ring, so that the fabric is folded in a star shape. Such fabrics are also referred to as "pleated". [21] In the case of folded fabrics, it is advantageous if the metal threads run parallel to the folds of the fabric.

[22] Unless the fabric itself is to perform the filter function, it is advantageous if the fabric forms a support structure for a filter material. In this case, the filter material may be a fine filter layer covering the support structure. As a fine filter layer, for example, a non-woven or cellulose paper can be used. A protective layer covering the fine filter layer on the clean side can likewise be designed in the form of a nonwoven. On the raw side, for example, one or more prefilter layers can cover the fine filter layer, and the prefilter layer can also be formed in the form of nonwovens and / or cellulose papers.

To avoid a mechanical impairment of the filter material and in particular for keeping open the folds, it is advantageous if the filter material is covered on the raw side by a sieve-like protective fabric. In this case, it may be provided that a fabric according to the invention, in particular as a supporting fabric, is also used as the sieve-like protective fabric.

[24] Particularly advantageous embodiments are shown in the drawing and will be described in more detail below. It shows:

FIG. 1 is a plan view of a fabric,

FIG. 2 shows a section through two layers of the fabric shown in FIG. 1,

Figure 3 is a plan view of a deformed fabric layer, as it is typically deformed and

Figure 4 shows a filter with such a fabric.

In the figures, the darker lines show threads of plastic and the lighter lines show threads of metal. Therefore, the cut filaments shown in Figs. 1 and 3 are thick and thin filaments of plastic, while the filaments shown therein as transverse filaments are made of metal. These transverse threads can also be partially replaced by plastic threads. Figure 1 shows thick plastic threads 1 to 5 with a diameter of 0.35 mm and in between each three thinner plastic threads 6 to 9. These thinner plastic threads have a diameter of 0.25 mm. The weft is formed by metal threads 10, 11, 12 (numbered only by way of example) with a diameter of 0.15 mm. This twill weave makes it possible to fold the fabric in the direction of the plastic threads, ie in the warp direction, in a simple manner.

[27] An example of a multilayer arrangement of the fabric shown in FIG. 1 is shown in FIG. There is in each case a thick plastic thread 1, 2 between two thin plastic threads 6, 7. [28] The folding of such a fabric 13 is shown in Figure 3. There, a fleece 15 is placed over the fabric 13, which rests directly on the fabric 13 in practice, so that the fabric 13 acts as a support structure and the nonwoven 15 as a filter material.

[29] In FIG. 4, a filter element generally designated by the reference numeral 20 is shown schematically. It comprises a cylindrical support tube 22, which is penetrated in the radial direction by a plurality of flow openings 23. In the circumferential direction, the support tube 22 is surrounded by a multilayer filter bellows 25, which is shown in Figure 5 for clarity partially in the manner of an exploded view. The filter bellows 25 are folded in a star shape by folds 27 running parallel to the longitudinal axis of the support tube 22 in such a way that along their circumference radially outer fold tips 28 and radially inner fold bases 29 follow one another alternately.

The filter bellows 25 has a three-layered filter material 32 with a fine filter layer in the form of a fleece 34, ie in the illustrated embodiment in the radial direction from outside to inside, on the raw side by a prefilter fleece 37 and on the clean side by a protective fleece 38 is covered. The nonwovens can be made, for example, from a plastic or glass fiber material.

[31] In the direction of flow 36, the filter material 32 is supported on the clean side on a support fabric 40, which rests flat against the protective fleece 38 of the filter material 32 and is also folded in a star shape. The support fabric 40 in turn is supported in the flow direction 36 in the region of the fold bases 29 on the support tube 22. [32] The structure of the supporting tissue 40 corresponds to the tissue shown enlarged in FIG. It is configured in a sieve or lattice fashion and is formed with warp threads 42 made of plastic material and weft threads 44 made of metal. The plastic material used here is preferably polyester, in particular PET, while the weft threads 44 are made of a metallic material, for example a stainless steel. The support fabric 40 is oriented such that the metallic weft threads 44 extend parallel to the pleats 27, while the made of plastic warp threads 42 are aligned perpendicular to the pleats 27. The metallic weft threads 44 are consequently subject to virtually no bending stress when folding the filter bellows 25 and during the filtration of the liquid. However, their use ensures that due to charge separation processes within the filter material 32 occurring electrical charges can be dissipated. This is particularly important when the support tube 22 is made of plastic. On the raw side, the filter material 32 is covered by a sieve-shaped protective fabric 46. In this case, for example, a metal mesh can be used. However, it can also be provided that the protective fabric 46 is identical to the supporting fabric 40 and also comprises plastic and metal filaments.

At the front, the filter bellows 25 is covered by an upper and a lower end cap 48 and 50, which are glued to the filter bellows 25. The lower end cap 50 forms a flow-tight closure of the filter element 20, while the upper end cap 48 has a central outlet opening 52.

[35] The liquid to be filtered is supplied to the outside of the filter element 20, so that it can flow through the filter bellows 25 radially from outside to inside and can reach the interior of the support tube 22 via the flow openings 23. Subsequently, the filtered fluid flows in the longitudinal direction of the support tube 22 to the outlet 52 and Uber out of the filter element 20 back out. In order to minimize the pressure drop of the fluid flowing through the filter bellows 25, it has proved to be advantageous if the warp threads 42 and weft threads 44 have different material thicknesses. Here, for those made of plastic, warp yarns having a diameter of about 0.25 mm with intervening warp with a diameter of about 0.35 mm proved to be particularly advantageous, while for the metallic weft threads 44 preferably a diameter of about 0.15 mm to 0.17 mm is provided , The mesh size of the support fabric 23 is about 0.6 mm to about 1.0 mm.

Claims

claims:

1 . Fabric, in particular for the filtration of liquids or gases with plastic threads in the warp and metal threads in the weft, characterized in that the warp has threads of different diameter.

2. A fabric according to claim 1, characterized in that the chain has a plurality of smaller diameter threads between larger diameter threads.

3. A fabric according to any one of the preceding claims, characterized in that the chain between threads of larger diameter each having more than one thread and in particular two to five threads with a smaller diameter.

4. Fabric according to one of the preceding claims, characterized in that the chain between threads with a larger diameter each having one or more threads of smaller diameter.

5. Fabric according to one of the preceding claims, characterized in that the shot has a share of threads made of plastic.

6. Fabric according to one of the preceding claims, characterized in that the threads in the weft predominantly have the same diameter.

7. A fabric according to any one of the preceding claims, characterized in that the threads have a diameter in the range between 50 μπι and 500 μηι.

8. Filter element, characterized in that it comprises a fabric according to one of claims 1 to 7.

9. Filter element according to claim 8, characterized in that it comprises a plurality of stacked fabrics according to one of claims 1 to 7.

10. Filter element according to claim 9, characterized in that the stacked fabrics are stacked such that the threads of larger diameter offset from each other.

1 1. Filter element according to one of claims 8 to 10, characterized in that it has a zigzag folded fabric.

12. Filter element according to claim 1 1, characterized in that the metal threads run parallel to the folds of the fabric.

13. Filter element according to one of claims 8 to 12, characterized in that the fabric forms a support structure for a filter material.

14. Filter with a filter element according to one of claims 8 to 13.

15. Use of a fabric, a filter element or a filter according to one of the preceding claims for the filtration of liquid, in particular hydraulic fluid.

16. Use according to claim 15, characterized in that the fabric based on the flow direction at least on the clean side as a filter material supporting support structure is used.