Abstract:
The present invention pertains to a device for cleaning gases containing particles with a bellows and with at least one filter element arranged in the bellows. To ensure effective filtration without limitation of the mobility of the bellows, the present invention provides for at least one filter element to be fixed at a bellows inner flange of a bellows corrugation in a positive-locking manner.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a United States National Phase application of International Application PCT/EP2012/000112 and claims the benefit of priority under 35 U.S.C. §119 of German patent application DE 20 2011 002 517.9 filed Feb. 9, 2011, the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention pertains to a device for cleaning gases containing particles, with a bellows and with at least one filter element arranged in the bellows. 
     BACKGROUND OF THE INVENTION 
     Such a device may be provided as an uncoupling element, optionally provided with additional individual components in exhaust gas lines of a motor vehicle as a soot filter. Furthermore, such a device may be used in the exhaust gas return line of a motor vehicle as a filter for loosened particles of a diesel particle filter. Moreover, there are many different further possibilities for use as filters, in which a flexible guiding element is necessary with the bellows. 
     In the devices of this class known from practice, filter elements are arranged, for example, in a rigid pipe socket, which at least protrudes into the bellows, on one side at a bellows element, or such a pipe socket protruding axially into the bellows is made of filter material. The mobility of the bellows is limited by such embodiments. 
     SUMMARY OF THE INVENTION 
     The basic object of the present invention is therefore to improve a device of this class for cleaning gases containing particles such that effective filtering of the gases takes place without limitation of the mobility of the bellows. 
     This object is accomplished according to the present invention in a device of this class by the at least one filter element being fixed in a positive-locking manner at a bellows inner flange of a bellows corrugation. 
     The mobility of the bellows is fully guaranteed by the solution according to the present invention, because the risk of collision of bellows corrugations with filter tubes inserted into the bellows or with other inserts during motion of the bellows is absent. The filter elements being held in a positive-locking manner according to the present invention at the bellows inner flange are moved together synchronously with the bellows corrugation during any motions of the bellows, be they axial, lateral or angular motions, without the risk of collision occurring, because the filter elements are held directly at a bellows corrugation in the described manner. Mobility is not limited hereby, because the filter elements are held just at exactly one bellows corrugation. 
     To fix the filter elements at a bellows corrugation, provisions may be made either for the outer circumference of the filter element to have, in some segments or over the entire circumference, a shape adapted to the contour of the bellows inner flange, extending partly around same, or for the filter elements to be held by clamps on the inside of the bellows inner flange. Provisions are made in the latter case in a variant of the present invention for the clamps to have outwardly projecting legs, which act each on an axial side of a bellows inner flange and to have two inner legs, which act on both sides on the filter element. 
     Provisions may, furthermore, be made in a variant for additional filter material to be enclosed between two filter elements fixed at the bellows inner flange of a bellows corrugation, wherein said additional filter material, which is inserted between two filter elements being held directly at bellows corrugations in said manner and is held by these, is soft and flexible, so that the mobility of the bellows is likewise not limited by this, either. 
     Metal meshes or metal fabrics, optionally in a multilayer form, preferably in the form of metal braids or square mesh fabrics or nonwoven metal netting, may be used as materials for the filter elements or inserted filter material. 
     As far as the process is concerned, the filter elements are fixed at the bellows inner flange in a positive-locking manner. This is done in the first, preferred embodiment by the outer circumference of the filter element being provided with a concave shape adapted to the contour of the bellows inner flange in some segments or over the entire circumference. The filter element is then inserted into the bellows up into a bellows corrugation and then compressed on both sides, while it radially expands and, in particular, the shape-adapted areas come into contact with the bellows inner flange in a positive-locking manner. 
     If more than one filter element held by corresponding adaptation of the circumferential contour is to be inserted into a bellows, these filter elements are given a shape adapted to the contour of the bellows inner flange of a bellows corrugation at first in some segments or over the entire circumference. Furthermore, they are brought at first to a slightly calotte-like shape by being pressed, after being inserted into a bellows corrugation, into the bellows inner flange in the area of a bellows inner flange by additional axial pushing with a punch and thus being fixed in a positive-locking manner. 
     In the case of the second type of fixation mentioned above by means of clamps, such clamps are first fixed with their radially outwardly projecting legs at the bellows inner flange of a bellows corrugation in a non-positive manner, one of the legs directed radially inwardly in the final state being still directed at first axially. Three clamps are preferably arranged over the circumference, but four or five clamps may be provided as well. 
     The filter element is then brought from an insertion side into the area of said clamps fixed at a bellows inner flange, with the inwardly directed leg of the clamps, which leg faces away from the insertion side, acting as a stop for the filter element. The at first axially directed leg facing the insertion side is finally bent off radially inwardly, so that the filter element is held between the two radially inwardly directed legs. 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a longitudinal sectional view through the upper half of a first embodiment of the device according to the present invention for cleaning gases containing particles; 
         FIG. 2  is a corresponding sectional view through another embodiment of the device according to the present invention; 
         FIG. 3  is a corresponding sectional view through another embodiment of the device according to the present invention with another type of fixation of the filter elements; 
         FIG. 4   a  is an enlarged sectional view of a clamp fixed to a bellows inner flange of a bellows corrugation before insertion of a filter element; 
         FIG. 4   b  is an enlarged sectional view of a clamp fixed at a bellows inner flange of a bellows corrugation with bent-off legs after insertion of a filter element; and 
         FIG. 5  is a longitudinal sectional view of another embodiment of the uncoupling element according to the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A device  1  according to the present invention for cleaning gases containing particles has a metallic bellows  2 . This is covered by a metal mesh or knitted tube  3  in the exemplary embodiment being shown, with profile rings  8  being provided at the two ends of the bellows for fixation. 
     Three filter elements  4  in the form of flat cylindrical filter disks are arranged within the bellows  2  at bellows inner flanges  2 . 1  of the bellows corrugations in the exemplary embodiment being shown. These filter disks are held by clamps  5  in the exemplary embodiment shown in  FIG. 1 . Three clamps  5  are preferably distributed uniformly over the circumference, but four or five clamps may be provided as well. The clamps  5  are held at the bellows inner flanges  2 . 1  of a bellows corrugation each by radially outwardly projecting legs  5 . 1  in a non-positive manner, while the disk-shaped filter elements  4  are clamped between radially inwardly projecting legs  6 ,  7 . 
     For assembly, the clamps  5  are first pushed over the bellows inner flange  2 . 1 , with the inner leg  7  directed towards the side from the assembly still being directed axially and hence at right angles to the other legs  5 . 1 ,  6  (as this can be seen in the right-hand filter element in  FIG. 1 ). The filter element  4  is then pushed in from the assembly side, the inwardly directed leg  6  acting as a stop for the filter element  4 . Leg  7  is finally bent off radially inwardly, so that filter element  4  is held between it and leg  6 , as it can be seen in the two elements on the left-hand side in  FIG. 1 . 
     The filter elements  4  preferably consist of metal mesh or metal fabric, such as metal braids or square mesh fabrics made of stainless steel, such as chromium, nickel or molybdenum steel with high corrosion resistance. The filter elements may be monolayer or multilayer elements, and the layers may have different mesh densities and wire thicknesses. The pore size of a filter layer may thus be, for example, between less than 1 μm to 100 μm with wire thicknesses on the same order of magnitude, and protective and support fabrics may have mesh sizes and wire thicknesses of up to the mm range. 
     Filter material  9  is also arranged between filter elements  4  in the form of flat cylindrical filter disks  4 ,  4   a  in the embodiment according to  FIG. 2 , this material being a soft, flexible filter material, such as a nonwoven metal netting, which does not limit the mobility of the bellows. 
     In the embodiment according to  FIG. 3 , the filter elements  4  are held at the bellows inner flanges  2 . 1  of a bellows corrugation in a positive-locking manner directly by the shape of their circumferential edge, as this is shown in  FIG. 3 . They consist of pressed metal wire or pressed wire mesh. A single filter element may now be fixed by being inserted at first into bellows  2  up to a bellows corrugation with a radial dimension that corresponds approximately to the bellows inner diameter and then being compressed axially from both sides, while filter element  4  expands radially and adapts itself to the bellows inner flange  2 . 1  of the bellows corrugation, as this can be seen in  FIG. 3 . 
     If more than one filter element  4 ,  4   a ,  4   b  is to be inserted into a bellows, the filter elements are prefabricated in a slightly calotte-like shape ( FIG. 5 , right-hand side). They can be slid freely over the bellows inner flange  2 . 1  with their circumferential edge  4 . 1 , which faces away from the push-in side A and is located on their concave side, while their convex-side circumferential flange  4 . 2  facing the push-in side A extends behind the bellows inner flange  2 . 1  in a positive-locking manner. If force is applied in the area of the circumferential edge  4 . 2  only, the filter disk  4   b  can be pushed over the bellows inner flange  2 . 1 . If force is applied centrally, by means of a punch, filter disk  4   b  with its circumferential edge  4 . 2  finds an abutment at the bellows inner flange  2 . 1  and is pressed, as a result of which the other circumferential edge  4 . 1  will also come into contact with the bellows inner flange  2 . 1  and the filter disk corresponds to the disks  4 ,  4   a.    
     While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.