Gas separation – With means securing or retaining separating media – Unit or cohesive sheet-like media in flow line or frame
Reexamination Certificate
1999-11-30
2001-07-31
Simmons, David A. (Department: 1724)
Gas separation
With means securing or retaining separating media
Unit or cohesive sheet-like media in flow line or frame
C055S509000, C055SDIG002, C055SDIG003, C055S385300
Reexamination Certificate
active
06267796
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates generally to a filter assembly. More particularly, the invention relates to a filter assembly including an accordion fold pack made of filter material, which is sealingly joined to a retention frame. Disposed at the end face of the retention frame, at least on one side, is a bracing whose length corresponds essentially to the length of the end-face fold. The bracing extends essentially parallel to the direction of the end-face fold edge of the accordion fold pack and is arranged in the end-face fold. European Patent 0 649 335 A1 discloses one such filter assembly. In that patent, the side walls of the accordion fold pack are in each case sealingly overlapped by a stabilizing strip. The stabilizing strip on the side facing the retention frame has a separately produced sealing strip that can be positioned against the retention frame under elastic prestressing, forming a seal. The seal between the retention frame and a filter housing surrounding the retention frame is effected by a further seal which is formed separately from the seal between the accordion fold pack and the retention frame.
SUMMARY OF THE INVENTION
The object underlying the invention is to further develop a filter assembly of the type discussed above, in such a way that it has a simple design with few parts and, because of this, can be produced inexpensively and easily from a standpoint of production engineering. In addition, the filter assembly should be easier to install and have better working properties.
To achieve the objective, disposed at the end face of the retention frame, is a double sealing lip which extends essentially parallel to the bracing in the direction of the end-face fold edge. The double sealing lip is able to swivel about a joint, formed like a film hinge, and can be positioned sealingly with the first sealing lip against the end-face fold wall, and with the second sealing lip against a filter-housing boundary wall facing the fold wall. The filter assembly thus allows effective sealing of the end face of the accordion fold pack with respect to the retention frame. The first sealing lip presses the end-face fold wall against the surface of the bracing, forming a seal. At the same time, the double sealing lip ensures an effective seal between the retention frame and the filter housing, obviating the need for using secondary sealing means such as sealing foam. The double sealing lip is jammed, under elastic prestressing, sealingly between the boundary wall of the filter housing and the fold wall adjacent to the bracing. The double sealing lip is preferably configured in one piece of uniform material.
According to one advantageous refinement, the retention frame can be made of a polymer material. In this case, it is advantageous that the entire filter assembly has a low weight and is resistant to corrosion.
The double sealing lip can also preferentially be made of a polymer material, one advantageous refinement providing for the possibility of configuring the retention frame and the double sealing lip from a uniform material, integrally and continuously with one another. Preferably polypropylene (PP) or polyethylene (PE) are used as materials both for the retention frame and for the double sealing lip, the angled double sealing lip being secured to the retention frame by the hinge joint. Such a one-piece design makes it substantially easier to handle the filter assembly, for instance during its installation in the filter housing.
The flexible attachment of the double sealing lip simplifies the pre-assembly of the accordion fold pack in the retention frame, as well as the assembly and disassembly of the entire filter unit.
The accordion fold pack and the retention frame form a unit which can be preassembled, this unit being inserted into the filter housing. During the installation of the unit into the filter housing, the double sealing lip is automatically positioned with its first sealing lip against the end-face fold wall of the accordion fold pack, and presses the fold wall sealingly together with the bracing. In addition, the second sealing lip, under elastic prestressing, is simultaneously positioned sealingly against the retention-frame boundary wall facing the accordion fold pack, so that this region is reliably sealed as well.
The elasticity of the double sealing lip can compensate for tolerances of the accordion fold pack and/or of the retention frame and/or of the filter housing subject to manufacture.
Rattling noises of the filter assembly during its use are eliminated by the elastic prestressing of the double sealing lip between the accordion fold pack and the filter housing.
According to a first embodiment, the double sealing lip is angled in the shape of a roof. The first sealing lip, which is positionable against the fold wall, is formed by the end facing away from the joint. The second sealing lip, positionable against the boundary wall, is formed by a vertex. The advantage of such an embodiment is that the double sealing lip has a simple geometric shape, and therefore is easy to manufacture.
According to a second embodiment, which is more advantageous in terms of technical function, the double sealing lip—is essentially Y-shaped when viewed in cross-section. The two sealing lips are formed by the respective ends of the forkshaped limbs. With increasing pressure difference between the upstream side and the downstream side of the filter assembly, the two sealing lips are applied more strongly against the respective adjoining surfaces, the contact pressure of the sealing lips against the sealing surfaces being essentially proportional to the pressure difference. Particularly in the case of comparatively large pressure differences of more than 500 Pa, the second embodiment of the double sealing lip is preferred over the first embodiment of the double sealing lip described at the outset, in order to minimize leakages to the greatest extent possible.
The accordion fold pack preferably is made of a non-woven fabric and is used, for example, as an automobile interior filter for air filtration. For most application cases, it is advantageous for one double sealing lip to be arranged on each end face of the retention frame.
REFERENCES:
patent: 5472379 (1995-12-01), Andress et al.
patent: 5509950 (1996-04-01), van de Graaf et al.
patent: 5554205 (1996-09-01), Ernst et al.
patent: 5620505 (1997-04-01), Koch et al.
patent: 5639287 (1997-06-01), Van de Graaf et al.
patent: 5720790 (1998-02-01), Kometani et al.
patent: 5755844 (1998-05-01), Arai et al.
patent: 5792229 (1998-08-01), Sassa et al.
patent: 5849187 (1998-12-01), Plaisier
patent: 5879423 (1999-03-01), Luka et al.
patent: 5902361 (1999-05-01), Pomplun et al.
patent: 5919284 (1999-07-01), Perry, Jr. et al.
patent: 6045598 (2000-04-01), Fath et al.
patent: 0 649 335 (1997-04-01), None
Firma Carl Freudenberg
Kenyon & Kenyon
Pham Minh-Chau T.
Simmons David A.
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