WO2012123398A1

WO2012123398A1 - Filter element cassette

Info

Publication number: WO2012123398A1
Application number: PCT/EP2012/054245
Authority: WO
Inventors: Marion Hartmann; Joachim Stinzendörfer; Sascha Roth; Beate BRANDT
Original assignee: Mann+Hummel Gmbh
Priority date: 2011-03-14
Filing date: 2012-03-12
Publication date: 2012-09-20
Also published as: DE102011013921A1

Abstract

The invention relates to a filter element cassette (1) for filtering liquids in machine tools, comprising at least one filter medium (2), which has an unfiltered side (3) for fluid (9) to flow into the filter medium (2) and for particles to be deposited and a filtered side (4), at which the filtered fluid (9) exits the filter medium (2), and a housing (5) having an interior (7), into which the filter medium (2) is inserted, the housing having an opening (6) for fluid (9) to be filtered to flow into the interior or for filtered fluid (9) to flow out of the interior (7), wherein the filter medium (2) comprises at least two bellows that extend flatly.

Description

Filter element cassette

Technical area

The invention relates to a filter element cassette, in particular for filtering working fluids in spark erosion machines.

State of the art

In various fields of technology particles of fluids, especially liquids, are deposited. The need for this is technology specific. For example, in erosion processes, the components removed from the workpiece by means of an electrical voltage between the workpiece to be machined and an electrode are removed by a non-conductive working fluid, eg. As an oil or deionized water, washed away. The removed ingredients must be separated from the liquid to maintain the quality, i. Purity of the liquid. For this purpose, filter elements with corresponding filter media are preferably used.

The document DE 196 08 589 discloses a filter element for gaseous or liquid media, which is insertable into a filter housing. The filter element has a zigzag-folded, annularly closed filter medium. At the end faces of the filter medium end plates are arranged. Liquid flows through the filter element from the inside to the outside, the particles impinging on the filter element accumulating on the surface of the filter element as a coating.

US Pat. No. 2003/038093 discloses a filter unit which has two cylindrical and concentrically arranged filter media which are each connected at one end to an inlet plate and at the other end to a closed outlet plate. From the published patent application DE 30 46 179 A1 a filter is known, in which within a cylindrical filter element, a further filter cylinder is arranged, wherein the filter cylinder form an annular gap space between their perforated plates.

Disclosure of the invention

The invention is therefore based on the object to provide an improved filtering arrangement. This object is achieved with a filter element cassette and a filter module with the features of the independent claims. Further advantageous embodiments of the invention are specified in the subclaims.

Accordingly, a filter element cassette for filtering liquids in machine tools, in particular working fluids in spark erosion machines, is proposed, which has a housing and a zigzag folded filter medium inserted into the housing, wherein the filter medium comprises at least two bellows extending flat.

Compared to zigzag-folded, closed-loop filter media, there is the advantage that the flat basic geometry of the filter medium enables a symmetrical filter surface arrangement and results in a particularly favorable filter surface streaming through the liquid. The filter surface of the filter medium can be used well.

A filter element cassette for filtering fluids, in particular liquids in machine tools, has at least, for example, a filter medium which has a raw side for flowing fluid into the filter medium and depositing particles and a clean side at which the filtered fluid exits from the filter medium , having. Further, a housing having an interior space into which the filter medium is preferably tightly confined the interior space, and which has an opening for flowing fluid to be filtered or outflow of filtered fluid into and out of the interior, wherein the filter medium as just extending Bellows is folded, provided.

In one embodiment, the opposing filter media are aligned with their raw sides facing each other. In an alternative embodiment, the opposing filter media are aligned with each other with their clean sides

The fluid to be cleaned either flows out of the housing through the opening into the interior of the housing and through the filter medium, or it flows through the housing nuei 1 1 icuiui 1 1 I ii ii Ii ici I i ctui 1 1 ue. vjei iciubeb a unu vei icibbi uiebeb ucti ni uie

Opening. As it passes through the filter media, the fluid is filtered by particles.

Preferably, the filter medium is flowed through in the direction of the interior of the housing to the outside. As a result, the particles deposited on the filter medium are held in the interior of the housing and contact with the separated particles is avoided. This results in a particularly practical handling of the filter element cassette as a whole. An operator can proceed without the risk of contamination of the liquid, such as distilled or deionized water, when changing the filter medium.

The filter medium is designed, for example, as a just extending bellows. It thus extends zigzag folded substantially in a plane, the folding edges can rest on a plane. For example, the folded edges of a respective bellows are located on the housing wall. This allows a symmetrical filter surface arrangement and uniform filter surface inflow through the fluid. The filter surface of the filter medium can be used optimally.

Preferably, the filter medium is detachably arranged in the housing so that it can be exchanged. Thus, the filter element cartridge can be flexibly adapted to changing conditions of use and spent filter media can be replaced.

According to one embodiment, the filter medium with the aid of a dimensionally stable support body, which is preferably at least partially made of plastic, inserted into the housing, which surrounds the edge of the filter medium. With the help of the support body, the filter medium can be stabilized in its shape, which facilitates handling and insertion into the housing. The filter medium is replaced by the support body a defined shape. The dimensionally stable support body also allows a particularly stable attachment to the housing. Preferably, the support body also extends between the filter medium and the housing, so that a dimensionally accurate insertion of the filter medium is supported. It is also possible that the filter medium rests directly on the housing and is only laterally supported by the support body for stiffening. As a result, no sealing between the support body and the housing is required. The filter medium can also be self-supporting. For example, the filter medium is so rigid that there is no significant deformation with a flow of fluid to be cleaned. Preferably, the bellows are capable of withstanding a filtration pressure of up to 5 bar between a raw fluid side and a clean fluid side. Machine-specific specifications may also require other filtration pressures.

The filter element cassette can be adapted to a wide variety of applications. The pleat height of the filter medium is preferably between 10 and 400 mm. Particularly preferably, the fold height is between 20 and 200 mm. In the case of the zigzag-folded filter medium, the pleat height here is understood to mean the distance between two surfaces which in each case lie against the zigzag-shaped fold at every second kink. The first surface is therefore located at the first, third, fifth, ... kink point and the second surface at the second, fourth, sixth, ... kink point. The pleat height is relevant for the available filter medium surface with a limited dimension of the filter element cassette.

In another embodiment, the pleat height within the filter medium varies by at least 20%. This results in a more uniform particle deposition over the surface of the filter medium. This is due to the fact that the areas of the folds of the filter medium with a higher fold height, which are further away from the kinks, are better reached by the particles through the adjacent folds with a lower fold height. Furthermore, the proposed filter element cassette allows a manufacturing tolerance can be reduced, in particular with regard to a uniform pleat height. In this respect, the filter element is easier to manufacture.

It is also conceivable to provide, for example, for further improving the Durchström- properties, alternately different fold heights. This is also referred to as a W-folding in which two equally short fold sections of a first width alternately follow two fold sections of a second width of equal length or equal width. A folding section is thereby formed by folding or folding edges. Limited folding orientation. The folding section is understood to mean the filter medium between two directly adjacent parallel folds.

The filter media are preferably arranged in the housing in such a way that folding edges of different bellows lie at a predetermined distance from one another.

According to another embodiment, at least two filter media are arranged opposite one another, in particular parallel to one another and overlapping one another. During operation, there is a pressure difference between the raw side and the clean side of the filter medium. This differential pressure causes liquid to pass through the filter medium. Due to the pairwise arrangement of the filter media, the forces resulting from the pressure difference on the filter media can be directed against each other, so that they neutralize and no resulting force must be supported. For example, the opposing filter media are arranged so close to each other that they abut each other or that the folds of the filter media interlock. By this close placement of the pleats of the filter media, the fluid to be filtered is forced to flow along and very close to the filter media. This achieves a very efficient filtering and good particle distribution on the filter medium surface. Even before the passage of the fluid to be filtered through the filter medium while particles are increasingly deposited on the filter medium surface. Preferably, the opposite filter media are aligned with their raw sides towards each other. As a result, the particles accumulate in the filter interior.

According to yet another embodiment, the zigzag-shaped filter medium is configured such that the fold edges of a first side of a bellows form a smooth surface and the second side of the bellows form a curved or angled surface. In particular, the bellows each comprise at least a first area with first fold heights and a second area with second fold heights.

According to one embodiment, the filter element cassette has a substantially cuboid outer contour. The parallelepiped Au contour allows a compact arrangement of several filter element cartridges together in a dense space. Further a simple stackability and a drawer-like insertion of multiple filter units is made possible in a common system.

A filter module is also described. A filter module has a plurality of filter element cassettes, which are arranged in a common module housing and connected in parallel or in series.

In a parallel arrangement, the filter element cassettes are flowed through in parallel, that is, the fluid to be cleaned flows in parallel in preferably all filter element cassettes. Thereby, the filter flow capacity of the filter element cassettes can be summed, which enables a large fluid flow rate.

In addition, the modular design with individual filter element cassettes allows occupied filter media can be replaced without the operation of the filter module must be interrupted. It can also be flexibly adjusted by selecting the number of filter element cartridges used in parallel the entire filter surface to the needs.

In a series connection of the filter element cassettes these are traversed behind each other by the same fluid. The fluid to be cleaned flows through a filter element cassette, is thereby filtered and the filtered fluid then flows into the next filter element cassette. In this way, an improved filter performance can be achieved. The series connection allows a stepped filtering. In one embodiment, filter element cartridges are used with different filter media. For example, prefiltering is accomplished with a filter element cartridge which performs coarse filtration and then downstream of the secondary or final filtration with a filter element cartridge which performs fine filtering.

Furthermore, different filter media can be staggered in succession, whereby the filter performance can be further improved. Preferably, the filter element cassettes are coupled together by means of a hose system. It is also possible that the filter element cassettes by means of a channel system in the module housing in a fluid flow system are interconnected. The duct system assumes the function of the hose system.

According to one embodiment, the filter module is formed as a drawer container with pull-out filter element cassettes. As a result, the individual filter element cassettes can be exchanged particularly quickly and easily. Preferably, the drawer container is designed to be movable. For this purpose, for example, several roles are attached to the bottom of the drawer container. This makes it possible, regardless of the weight of the drawer container, to quickly move the drawer container to a desired place of use. This allows a particularly flexible use of the drawer container.

Further possible implementations of the invention also include not explicitly mentioned combinations of features or embodiments described above or below with regard to the exemplary embodiment. The skilled person will also add individual aspects as improvements or additions to the respective basic form of the invention.

Further embodiments of the invention are the subject of the dependent claims and the embodiments of the invention described below. Furthermore, the invention will be explained in more detail by means of embodiments with reference to the accompanying figures.

Furthermore, the invention will be explained in more detail by means of embodiments with reference to the accompanying figures.

Brief description of the drawings

It shows:

1 shows two perspective views of a filter element cassette according to a first embodiment;

2 is a perspective sectional view of a plurality of filter element cassettes according to a second embodiment;

3 shows a perspective schematic representation of a filter module according to an embodiment. 4 shows a schematic illustration of zigzag-shaped filter medium according to an embodiment; and

5 shows a schematic cross-sectional view of a filter element cassette according to a further embodiment.

Embodiments of the invention

Fig. 1 shows two perspective views of a filter element cassette 1 according to a first embodiment. The filter element cassette 1 is cuboid shaped as a kind of drawer with a handle 15. The housing 5 of the filter element cassette 1 is bounded on one side by outflow openings 14, which are provided in a perforated plate 16 in this embodiment. An opening 6 can be seen in the left-hand illustration, which in this embodiment allows fluid 9 to flow into an interior 7 of the housing 5 of the filter element cassette 1. In the right perspective view, the outflow of the fluid 9 from the housing 5 through the perforated plate 16 is also shown in arrow form. In the housing 5, the fluid 9 is filtered when passing through a single zigzag folded filter medium 2. The housing 5 is designed in this embodiment like a drawer with a handle 15 for pulling or insertion. Fig. 2 shows a sectional view of a plurality of filter element cassettes 1 according to a second embodiment. The right-hand illustration shows a filter module designed as a car. This inserts are provided for the filter element cartridges 1. The housing 5 has, as in the first embodiment, an opening 6 for a fluid supply in the housing 5 of the filter element cassettes 1 and a plurality of outlet openings 14 for discharging the fluid from the housing 5. Two filter media 2, each folded in a zigzag shape, extending flat, are arranged opposite each other an inner space 7 of the housing abgenzend. The filter media 2 are inserted into the housing 5, for example with the aid of a support body 8. The filter media have a pleat height h perpendicular to their longitudinal extension direction, which is shown here with a double arrow, and is to be understood as a distance between parallel planes, each extending through the kinks of the filter medium 2 on one side.

On the right side of Figure 2 is shown how to be cleaned fluid duch a Pump 1 1 via hoses 13 to the respective inlet openings 6 is supplied. Below the filter element cassettes 1 is a collecting space 15 for the filtered fluid, such as a contaminated medium for EDM devices (EDM = electrical discharge machines). At a drain or outlet 17, the cleaned fluid exits, for example, as a clean dielectric.

FIG. 3 shows a perspective schematic illustration of a filter module 10 according to an embodiment. The filter module has a plurality of filter element cassettes 1, which are arranged in a module housing 12. One can also speak of a filter cabinet. The filter elements 10 are connected in parallel in this embodiment. This shows the filter capacity of the individual filter element cassettes 1 in the filter module 10. Shown here is the rear side of the filter module 10 with the connection of the individual filter element cassettes 1 to a common distributor via tubes 13. The distributor can be equipped with a pump 11 , The filter element cassettes 1 are drawer-like inserted from the image plane out of the picture plane in the filter module 10 and removed in the reverse direction again. By the drawer-like system of substantially cuboid shaped filter element cassettes 1 in the filter module 10 results in a dense and thus space-saving arrangement of filter element cassettes 1, which can be easily replaced.

FIG. 4 shows a schematic representation of a zigzag-shaped filter medium in cross-section. The zigzag-shaped filter medium 2 is designed as a bellows with a W-fold. The profile of the folds corresponds to a juxtaposed W. In the orientation of FIG. 4 below, the fold edges 18 form a flat surface. The upper folded edges 19, 20 alternately give a different height of the folds. It can be seen narrow folding sections 2A and wide folding sections 2B, which are separated in pairs by a folding edge. Two adjoining narrow folding sections 2A each adjoin two adjoining wide folding sections 2B.

The figure shows a schematic cross-sectional view of a filter element cassette 1 according to another embodiment. There are two flat bellows 2 are arranged in the housing 5 opposite to each other. In the housing 5, an opening 6 for introducing the fluid to be filtered into the inner space 7 between the raw sides of the Fal- Tenbalge 2 arranged. The folds of the bellows 2 are designed such that the inwardly directed fold edges follow a contour 23, which is indicated by dashed lines in FIG. This results in areas 21 having a first fold height and one or more areas 22 having a second fold height. By modulating the fold amplitudes, the flow of the fluid can be influenced.

Although the present invention has been described in terms of preferred embodiments herein, it is not limited thereto, but modifiable in a variety of ways.

Claims

claims

1 . Filter element cassette (1) for filtering liquids in machine tools, in particular working fluids in spark erosion machines, with a housing (5) and a zigzag folded filter medium (2) inserted in the housing (5), the filter medium (2) being at least two includes just extending bellows.

2. Filter element cassette (1) according to claim 1, characterized in that the filter medium (2) by means of a dimensionally stable support body (8) is inserted into the housing (5), which surrounds the filter medium (2) at the edge.

3. filter element cassette (1) according to claim 1 or 2, characterized in that a fold height (h) of the filter medium (2) is between 10 and 400 mm.

4. filter element cassette (1) according to any one of claims 1-3, characterized in that a fold height (h) of the filter medium (2) varies by at least 20%.

5. Filter element cassette (1) according to one of the preceding claims, characterized in that at least two filter media (2) are arranged as a bellows opposite each other, in particular parallel to each other.

6. filter element cassette (1) according to claim 5, characterized in that the opposite filter media (2) are arranged so close to each other, that fold edges of the filter media (2) engage.

7. filter element cassette (1) according to claim 5 or 6, characterized in that the opposite filter media (2) with their raw sides (4) are aligned with each other.

8. filter element cassette (1) according to one of claims 1-7, characterized in that the filter element cassette (1) has a substantially cuboid outer contour.

9. Filter module (10) with a plurality of filter element cassettes (1) according to one of the claims che 1-8, characterized in that the filter element cassettes (1) are arranged in a common module housing (12) and connected in parallel or in series.

10. Filter module (10) according to claim 9, characterized in that the filter module (10) as a drawer container, which is in particular movable, with extendable filter element cassettes (1) is formed.