DE20112179U1 - Filter element - Google Patents

Description

State of the art

The invention relates to a filter element with a filter medium applied to a support body according to the preamble of patent claim 1. Furthermore, the invention relates to a filter with a housing into which the said filter element is introduced, according to the preamble of patent claim 9.

Filter elements of the type described above are known, for example, from EP 0 718 022. This document discloses a gap filter for liquids or gases with a filter element in which a support body is surrounded by a filter body. The filter body is designed as a plate with slot-shaped openings and rests on the support body. The support body is designed in such a way that if the filter body is damaged, the support body ensures sufficient filtration. The filter body is cleaned with a backwash device. The backwashed fluid is removed from the filter via an outlet.

Cleaning the filter element with a backwash device is advantageous for dirt particles <30 μηι. However, reliable cleaning cannot be guaranteed for particle sizes >30 μηι. These larger particles can become wedged in the slots of the filter body so that they cannot be removed by backwashing. This can gradually clog the filter body until no more fluid can flow through the filter body.

The object of the invention is therefore to create a filter element in which even larger dirt particles can be reliably cleaned from the filter medium. This object is achieved by the features of patent claim 1 and patent claim 9.

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Advantages of the invention

The filter element according to the invention has a cylindrical support body which is permeable to the fluid to be cleaned. The cylindrical shape of the support body can also deviate from the circular shape and can be e.g. elliptical. This support body is surrounded by a filter medium which is designed as a filter film. The filter medium has perforations which are designed in such a way that the fluid can flow through, but contaminants are separated. These perforations can be designed as slits or circular holes, for example, with the dimensions of the perforations being adapted to the particle sizes to be separated.

The smaller the particles that need to be filtered out, the smaller the perforations need to be. To prevent the filter medium from becoming clogged, it is mechanically cleaned at defined intervals. This means that particles >30 μm in particular can be reliably removed. The time for cleaning can, for example, be set at a defined time interval or depending on how dirty the filter medium is. Since the filter medium is designed as a filter film, the separated particles cannot become wedged in the perforations, which means they can be easily cleaned off. To enable mechanical cleaning of the filter medium, the filter medium is arranged on the support body in such a way that relative movement between the support body and the filter medium is prevented. The filter medium can be permanently connected to the support body, for example by welding or gluing. The fixed attachment of the filter medium to the support body prevents the risk of damage to the filter medium during cleaning.

According to an advantageous embodiment of the invention, the filter film has a thickness of 0.1 to 1 mm. Filter films of this design are easy to arrange around the support body because the bending stiffness is low. This means that filter elements with very small cross-sectional areas can also be produced. Furthermore, the pressure loss caused by the filter film is very low compared to thicker filter media.

In a special design, the filter medium is connected to the support body in a form-fitting manner. These form-fitting connections can be distributed around the entire circumference of the support body or only in certain areas, such as the end areas or along a surface line. The support body can have nubs, for example, which engage in recesses in the filter medium.

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With this type of connection, the relative movement between the support body and the filter medium can be effectively prevented.

It is advantageous that the filter medium is attached to the support body without folds. This prevents increased stress from occurring in certain areas when the filter medium is mechanically cleaned. Increased stress could potentially lead to damage to the filter medium. Furthermore, a fold-free arrangement of the filter medium ensures that the distance between the mechanical cleaning device and the filter medium is almost constant and does not have any jumps. This allows the filter medium to be cleaned evenly.

According to an advantageous embodiment, the filter medium is wound around the support body under tension and fixed at its ends. The tension causes the filter medium to adhere to the support body in all areas without play. The tension must be selected in such a way that the filter medium is not loaded beyond its permissible tensile strength. However, it must be ensured that the tension is sufficient to fix the filter medium immovably on the support body even when it is being cleaned.

One way to fix the filter medium to the support body is to solder the ends of the filter medium together. The ends of the filter medium wound around the support body meet without overlapping. To ensure that the solder does not form a bead on the side of the filter medium that is to be cleaned, a groove is provided in the support body, for example, which receives the solder and thus enables a bead-free connection. This means that there is no accumulation of material in the area of the soldering point, which would cause increased stress during mechanical cleaning.

It is advantageous that the mechanical cleaning of the filter medium is carried out with a scraper. To clean the filter element, the scraper and the filter medium are moved relative to each other. Both the scraper and the filter element can be moved with the filter medium. A movement of both components is also conceivable, with the components either rotating in opposite directions or, with the same direction of rotation, one component moving faster than the other. This ensures that the filter medium is cleaned reliably.

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Another design provides for the scraper to be made of a softer material than the filter medium. The filter medium can be made of stainless steel, nickel, sintered material or plastic, for example. Depending on the material selected for the filter element, the scraper must then be made of a softer material, such as plastic, copper 5 or soft alloys. The material pairing must be designed in such a way that the filter element is not damaged. The filter medium must also not be damaged by the movement of the separated particles on the filter medium. A robust material must therefore be selected for the filter medium. The scraper must be destroyed before the filter medium is damaged. This can prevent the filter medium from failing due to excessive abrasion.

The filter element according to the invention can be used in a filter with an openable housing. This housing has an inlet through which contaminated fluid can flow into the housing. Furthermore, an outlet is arranged in the housing through which the cleaned fluid can flow out of the housing. The outlet is sealed off from the inlet by the filter element. In the filter, in particular polyol, cyanate or paints can be cleaned of, for example, crystallized, sedimentable dirt.

In a further embodiment of the filter, a dirt outlet is provided in the housing through which the separated contaminants can be removed from the filter. The contaminants, which are cleaned from the filter element in particular with the scraper, sink downwards in the housing and are discharged from the housing. The dirt outlet can be designed with a valve that can be opened and closed, whereby the contaminants can be removed from the housing continuously or only when required.

These and other features of preferred developments of the invention emerge not only from the claims but also from the description and the drawing, wherein the individual features can be implemented individually or in combination in the form of sub-combinations in the embodiment of the invention and in other fields and can represent advantageous and protectable embodiments for which protection is claimed here.

VSS 1839

23.07.2001

drawing

Further details of the invention are described in the drawing using schematic embodiments.

Figure 1 a filter element in section,

Figure 2 shows a section of the filter element,

Figure 3 shows a section of the filter element,

Figure 4 shows a filter in section and

Figure 5 shows a section of the filter.

Description of the embodiments

Figure 1 shows a filter element 10 in partial section. The filter element 10 has a support body 11 and a filter medium 12 wound around the support body 11. The support body 11 is formed by a triangular profile wire 13 which is supported on longitudinal struts 14. The profile wire 13 points with its pointed side outwards towards the filter medium 12, whereby the filter surface is not unnecessarily reduced. The filter medium 12 is designed as a thin split film 15 with a thickness of approx. 0.5 mm. This split film 15 has slits 16 through which only the cleaned fluid can flow. Contaminants are separated and remain on the outer surface of the split film 15. The filter element 10 also has two end rings 17 which seal the filter medium 12.

Figure 2 shows a section of the filter element 10 along the line A-A. Components corresponding to Figure 1 are provided with the same reference numerals. The split foil 15 is placed under tension without play around the profile wire 13 of the support body 11. In this case, a relative movement between the split foil 15 and the profile wire 13 is effectively prevented. A soldered connection 18 is provided to fix the split foil 15. This soldered connection 18 is designed in such a way that the ends of the split foil 15 abut against one another. To reinforce the soldered connection 18, a reinforcing strip 19 is provided, which is arranged in a groove in the profile wire 13. The solder is introduced between the reinforcing strip 19 and the split foil 15, whereby

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where the solder must not penetrate through the split foil 15. The radial tensile forces are absorbed by this solder connection 18, whereby the split foil 15 rests securely against the support body 11 even under mechanical stress.

Figure 3 shows another section of the filter element 10 in section along the line B-B-. Components corresponding to Figure 1 are provided with the same reference numerals. In this illustration, it can be seen that the end ring 17 has a recess 21 in its inner area 17, which is intended to facilitate assembly. After joining, the end ring 17 is sealed to the split film 17 with a solder seam 22. This solder seam 22 serves not only to provide a reliable seal but also to fix it in place, as it is connected to both the split film 15 and the support body 11.

Figure 4 shows a filter 23 in section. The filter 23 has a housing 24 with a housing pot 25 and a housing cover 26. The two housing parts 25, 26 are detachably connected to one another with screws 27. An inlet 28, an outlet 29 and a dirt outlet 30 are arranged in the housing pot 25. The inlet 28 is connected to a raw side 31 and the outlet 29 to a clean side 32. A filter element 10 is provided for sealingly separating the raw side 31 from the clean side 32. This filter element 10 essentially corresponds to Figure 1. A mechanical cleaning device 33 is provided for cleaning the filter element 10. This cleaning device 33 has a scraper 34 which loosens the contaminants deposited on the filter element 10. The filter element 10 is clamped into a holding device which has an upper disk 35, a lower disk 36 and connecting supports 37. The upper end disk 35 is fixed in place to the housing pot 25 via holding webs 42 and a support ring 43. The connecting supports 37 are screwed to the disks 35, 36. The filter element 10 is rotatably mounted between the disks 35, 36 and can be rotated via a handwheel 38 with a shaft 39. The rotation of the filter element 10 can also be carried out by a gear (not shown) as an alternative to manual movement. The rotation guides the filter element 10 past the scraper 34, whereby the contaminants are scraped off around the entire circumference. These scraped-off contaminants sink and are discharged from the filter via the dirt outlet 30.

Since the scraper 34 must rest on the filter element 10 with a preset force, an adjustment device 40 is provided which presses the scraper 34 onto the filter element 10. The force acting on the filter medium 12 through the scraper 34 is

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however, less than the holding forces acting between the filter medium 12 and the support body. Thus, the scraper 34 cannot cause any relative movement between the filter medium 12 and the support body 11, which would destroy the filter medium 12.

Figure 5 shows a section of the filter according to Figure 4. Components corresponding to Figure 4 are provided with the same reference numerals. This illustration shows an alternative design of the scraper 34. The scraper 34 rests against the filter element 10 with a pre-tensioned spring force, with the guide 41 of the scraper also resting against the filter element 10. The guide 41 of the adjustment device 40 is screwed to the housing pot, whereby the position of the scraper 34 is fixed.

Claims (10)

1. Filter element with a cylindrical support body ( 11 ) permeable to the fluid to be filtered and a filter medium ( 12 ) applied to this support body ( 11 ), wherein the filter medium ( 12 ) is designed such that impurities can be filtered out of the fluid, and wherein the filter medium ( 12 ) can be cleaned, characterized in that the filter medium ( 12 ) is designed as a filter film ( 15 ), wherein the filter medium ( 12 ) is fastened to the support body in such a way that a relative movement between the support body ( 11 ) and the filter medium ( 12 ) is prevented, and wherein the filter medium ( 12 ) can be mechanically cleaned. 2. Filter element according to claim 1, characterized in that the filter film has a thickness of approximately 0.1 to 1 mm. 3. Filter element according to one of the preceding claims, characterized in that the filter medium is positively connected to the support body ( 11 ). 4. Filter element according to one of the preceding claims, characterized in that the filter medium ( 12 ) is fastened to the support body ( 11 ) without folds. 5. Filter element according to one of the preceding claims, characterized in that the filter medium ( 12 ) is wound under tensile stress around the support body ( 11 ) and fixed at its ends. 6. Filter element according to claim 5, characterized in that the filter medium ( 12 ) is soldered at its ends. 7. Filter element according to one of the preceding claims, characterized in that the filter medium ( 12 ) can be cleaned with a scraper ( 34 ). 8. Filter element according to one of the preceding claims, characterized in that the scraper ( 34 ) consists of a softer material than the filter medium ( 12 ). 9. Filter with an openable housing ( 24 ), wherein the housing ( 24 ) has an inlet ( 28 ) and an outlet ( 29 ), wherein the outlet ( 29 ) is sealingly separated from the inlet ( 28 ) by a filter element ( 10 ), characterized in that the filter element ( 10 ) is designed according to claims 1 to 8. 10. Filter according to claim 9, characterized in that a dirt outlet ( 30 ) is provided through which the separated contaminants can be removed from the filter.