DE9420505U1 - Gas filter package - Google Patents

Description

DIPLrING. HORST ROSE DIPLrING. P&TpR.'KOSEL .OIPIftfNG: PETER SOBISCH PATENT ATTORNEYS * ADMISSIONED BY THE EUROPEAN PATENT OFFICE - EUROPEAN PATENT ATTORNEYS

Patent Attorneys Rose, Kosel & Sobisch Odasirasse 4a, D-37581 Bad Gandersheim

Odastrasse 4a

D-37581 Bad Gandersheim

Germany

Telephone {05382)4038 Fax (05382)4030

Your ref.

Our reference/Ourref. 2907/40

Date/Date 21 December 1994

Camfil GmbH

01

DESCRIPTION

Gas filter package

The invention relates to a filter package according to the preamble of claim 1.

Known filter packages of this type essentially use dimensionally stable cover grids, e.g. made of sheet metal or plastic injection molded parts. This design is complex in terms of the individual parts and assembly.

A known filter package (US 4 135 900 A, Fig. 8 to 10) rests with its clean gas side on rigid, flat support grids that are held in place by crossbar profiles of a surrounding frame and are presumably made of metal wire. The task of the support grids is to limit deflection of the filter package in the flow direction and corresponding damage to the filter package, even at high differential pressures.

-2-PK/K

Bank account: NORD/L8, NL Bad Gandersheinn (bank code 250 500 0O)T

. 3?11g 9^0 · PcßtBirojjranto'Postgiroamt Hannover (BLZ260100 30), Account No. 667 15-307

Ol From GB Patent Specification 1 272 564 it is known to support a self-supporting filter package with the clean gas side on a rigid, coarse-mesh metal grid. Metal rods are placed at a distance from one another across the dust-gas side vertices of the filter package. A flat cover layer made of a filter material made of open-pore plastic foam is placed on the inlet side of the metal rods and on the outlet side of the metal grid.

A circular, self-supporting air filter cartridge for internal combustion engines is known from OE publication 2 407 329. The dust-air-side, outer vertices of the folded filter package rest against an outer protective ring made of perforated sheet metal.

The clean air side, inner vertices of the filter package are bonded to an inner, strip-shaped flame protection metal grid by means of a continuous adhesive strip laid across the vertices.

The invention is based on the object of creating a mechanical protection for the sensitive pleated filter material in a cost-effective manner.

This object is achieved by the features of claim 1. The flexibility of the grid allows the grid to be removed from a roll, for example, to produce the filter package and to be attached to the filter material during or after the completion of the zigzag-folded filter material. The distance between the threads can be 3 to 5 mm, for example, and in any case be so large that the pressure drop on the filter package caused by the grid remains negligible. The grid preferably has, despite its

-3-

Thanks to its flexibility in all directions, it has a high resistance to stretching. The grid therefore contributes significantly to the dimensional stability of the zigzag-folded filter material. A particular advantage is that the grid offers excellent mechanical protection of the zigzag-folded filter material from external influences, such as falling objects or the hands of service personnel when handling the filter packages. In many cases, it is sufficient to provide such a grid on just one side of the filter package, e.g. to achieve special grip protection on this side.

The features of claim 2 enable the securing properties of the grid to be improved.

According to claim 3, the bonding of the grid is promoted by its design.

The features of claim 4 facilitate the connection of the grid to the filter material.

The features of claim 5 are particularly suitable for the mechanical application of the grid to the zigzag-folded filter material.

According to claim 6, a very extensive connection of the grids with the vertices is obtained.

According to claim 7, the adhesive strands of the filter material, which are usually present anyway, can be used to connect it to the grid. These adhesive strands can simultaneously fulfill the function of keeping the folds at an optimal distance from one another in a manner known per se. In this way, the adhesive strands act as separators between the individual folds of the filter material.

-A-

„4-Ol terials.

With the design according to claim 8, extremely low elongation of the grid under tensile stress is to be expected. The dimensional stability of the filter package produced in this way is correspondingly high.

The features of claim 9 or 10 also lead to very satisfactory results in most cases.

According to claim 11, the covering can consist, for example, of a plastic with which the threads can be impregnated or simply covered . Such a covering can also be made self-extinguishing.

With the features of claim 12, the connection at the fastening points can be made, for example, by melting or gluing. The result is in any case an increased dimensional stability of the grid with simultaneous flexibility.

According to claim 13, the covering can consist, for example, of a hot-melt adhesive, which then alone fixes the grid to the vertices of the filter material.

The features of claim 14 offer mechanical protection to the dust gas side of the filter package even if a part of the dust gas side is covered with the gas distribution element. Preferably, the gas distribution element is in contact with the dust gas side and the grid is in contact with the gas distribution element. The gas distribution element is preferably designed as a thin fiber fleece and ensures that the gas is distributed as evenly as possible.

-5-

Oil dust air above the dust air side of the filter package.

According to claim 15, the sheet-shaped web acts as a laminator, which results in good direction and uniformity of the gas flow. The laminator preferably lies on the corresponding side of the filter package, and the grid in turn lies on the laminator.

These and other features and advantages of the invention will become apparent from the following description of embodiments based on the drawings. It shows:

Fig. 1 a longitudinal section through part of a filter package ,

Fig. 2 the view according to line II-II in Fig. 1,

Fig. 3 is a longitudinal section through part of another embodiment of the filter package,

Fig. 4 shows detail IV in Fig. 3 in an enlarged view,

Fig. 5 is a longitudinal section through a part of yet another embodiment and

Fig. 6 a longitudinal section through part of yet another embodiment of the filter package.

Fig. 1 shows a filter package 1 for filtering gases, in particular air. A filter material 2 known per se is folded in a zigzag pattern, with the dust-gas-side vertices 3 of the folds defining a dust-gas side 4 and the clean-gas-side vertices 5 defining a clean-gas side 6 of the filter package 1. The dust gas is directed in the direction of an arrow 7

-6-

-δ-

Oil supplied.

The individual folds of the filter material 2 form V-shaped pockets on both the dust gas side and the clean gas side, which should be maintained in their optimal V-shape even when the filter is in operation for optimal filtering effect. This is done according to Fig. 1 by adhesive strands 8 and 9, which are shown exaggeratedly thick for clarity, which run on the one hand over the dust gas side peaks 3 and on the other hand over the clean gas side peaks 5.

Adjacent folds of the filter material 2 each have a pitch 12.

A coarse-meshed, flexible grid 13 is arranged directly in front of the dust gas side 4 and directly behind the clean gas side 6 of the filter package 1. Each grid 13 has longitudinal threads 15 arranged at a pitch 14 from one another and transverse threads 17 arranged at a pitch 16 (Fig. 2). The longitudinal threads 15 and the transverse threads 17 are fastened to one another at their intersection points 18 by fastening points 19. In this way, a grid 13 is created that is flexible but extremely tensile in all directions. The tensile strength is particularly high when the longitudinal threads 15 and/or the transverse threads 17 each have a glass fiber bundle. The fastening points can be formed by locally applied adhesive or by a covering 20 (Fig. 4) of the longitudinal threads 15 and/or a covering 21 of the transverse threads 17. The coverings 20, 21 can consist, for example, of a plastic or hot-melt adhesive, which becomes molten at elevated temperatures and, when cooled again, creates a firm bond to the other threads.

-7-

-7-

Ol The grids 13 can be prefabricated in this way and kept ready as an endless web material, e.g. on a supply roll. The grid web is pulled off the supply roll and laminated onto the dust gas side 4 and/or clean gas side 6 of the filter package 1 during production. The fact that the adhesive strands 8, 9 are adhesive until a certain temperature is undershot can be used to advantage. If the grid 13 with its longitudinal threads 15 is placed on the tops of the adhesive strands 8, 9 and lightly pressed on, a firm bond is created between the adhesive strands 8, 9 and the longitudinal threads 15 after the system has cooled. The web of grid material 13 then only needs to be cut into appropriate lengths.

The pitch 14 can preferably be the same or a multiple of the pitch 12. This ensures that each longitudinal thread 15 is opposite a vertex of an adhesive strand 8, 9. In addition to these adhesive points or instead of these adhesive points, the longitudinal threads 15 can be connected, e.g. glued, to the opposite vertex 3, 5 of the filter material 2 over essentially their entire length. In this way, at least some of the folds of the filter material 2 can be additionally fixed relative to one another. This again improves the efficiency and service life of the filter packages 1.

According to Fig. 2, the pitch 16 can be chosen to be equal to the pitch 14 or different from it. The distance between the adhesive strands 8, 9 in the direction of the longitudinal threads 15 is determined according to the special requirements for the dimensional stability of the V-shaped pockets of the filter material.

-8th-

Ol rials 2 elected.

In all drawings, identical parts are provided with identical reference numbers.

In Fig. 3, the pitch of the longitudinal threads 15 differs from the pitch of the vertices 3 of the filter material 2. In this case, it is sufficient if one of the longitudinal threads 15 is occasionally connected to an opposite adhesive strand 8.

Fig. 4 shows one of the crossing points 18 and the associated fastening point 19, which was created by fusing the sheaths 20, 21 together. Fig. 4 also indicates that the threads 15, 17 each consist of a glass fiber bundle.

The grid 13 according to Fig. 5 is woven from the longitudinal threads 15 and the transverse threads 17. Here, longitudinal threads 15 can be connected to the vertices of the adhesive strands 8 in the manner described above. Additional bonds of the grid 13 to the filter package 1 can take place by locally gluing the transverse threads 17 at adhesive points 22 to vertices of the adhesive strands 8 or to the vertices 3 of the filter material 2.

The filter package 1 according to Fig. 6 is equipped with the grid on its dust gas side in the manner described above. A sheet-shaped web 23 made of a gas-permeable, fine-mesh material, e.g. a nonwoven fabric, is laid on the clean gas side vertex 5 of the filter material 2 over the entire clean gas side 6. The web 23 acts as a laminator and results in only an extremely low pressure drop. The web 23 ensures that the clean gas is pressed into the filter material with essentially

-9-

-9 —

Ol emerges in the same direction and at the same speed. The web 23 is expediently connected to the vertices 5, e.g. by local gluing to the vertices of the adhesive strands 9 (Fig. 1 ).

The grid 13 is placed on the lower or outlet side of the web 23 and is held there either by a circumferential frame (not shown in Fig. 6) or by gluing or welding at least some of the longitudinal threads 15 to the web 23.

Claims (7)

DiPL-ING. HORST ROSE DIPL-ING. PETER'KQSEL : DIPL.ING.rRETER SOBISCH PATENTAN^/ÄL?!·· ··· "·· ··' ^: ADMITTED TO THE EUROPEAN PATENT OFFICE - EUROPEAN PATENT ATTORNEYS Patent Attorneys Rose, Kosel & Sobisch · Odastrasse 4a Odastrasse4a, D-37581 Bad Gandersheim D-37581 Bad Gandersheim Germany Telephone {05382)4038 Fax (05382)4030 yourreferenceVYourref. Ourreference/Ourref. Date/Date 2907/40 21 December 1994 Camfil GmbH EXPECTATIONS 1. Filter package (1) for filtering gases, in particular air, with a zigzag folded filter material {2), wherein dust-gas-side peaks (3) of the folds define a dust-gas side (4) and clean-gas-side peaks (5) of the folds define a clean gas side (6) of the filter package (1), and wherein a grid (13) is arranged in front of the dust gas side (4) and behind the clean gas side (6), characterized in that immediately in front of the dust gas side (4) and/or immediately behind the clean gas side (6) a coarse-meshed, flexible grid (13) made of longitudinal threads (15) and transverse threads (17) arranged at a distance from one another is arranged in a surface- -2-PK/K Bank account: NORD/LB. NL Bad Gandersheim (bank code 250 500 OQ). &atviir,*2£ &iacgr; 1 g 9^> Pegtgiro Jorrte^Postgiroamt Hannover (bank code 250100 30), account no. 66715-307 -2- Ol . is arranged covering, and that each grid (13) is attached to the filter pack (1). 2. Filter package according to claim 1, characterized in that the longitudinal threads (15) and the transverse threads (17) are fastened to one another at least at some of their crossing points (18) by fastening points (19). 3. Filter package according to claim 1, characterized in that the longitudinal threads (15) are interwoven with the transverse threads (17). 4. Filter package according to one of claims 1 to 3, characterized in that the longitudinal threads (15) run parallel to the vertices (3;5) of the folds 5. Filter package according to claim 4, characterized in that at least some of the longitudinal threads (15) are each at least locally fastened to an opposite vertex (3; 5). 6. Filter package according to claim 5, characterized in that the at least some longitudinal threads (15) are provided with an adhesive on their side facing the apex (3;5) and are glued to the apex (3;5) over their entire length. -3- —3— Oil 7. Filter package according to claim 5, characterized in that the at least some longitudinal threads (15) are glued to adhesive strands (8;9) of the filter package (1) which run at a distance from one another across the vertices (3;5). 8. Filter package according to one of claims 1 to 7, characterized in that each thread (15;17) comprises a glass fiber bundle. 9. Filter package according to one of claims 1 to 7, characterized in that each thread (15;17) comprises a plastic fiber bundle. 10. Filter package according to one of claims 1 to 7, characterized in that each thread (15; 17) is designed as a solid plastic thread. 1511. Filter package according to one of claims 1 to 10, characterized in that each thread (15;17) is provided with a covering (20;21). 12. Filter package according to claim 11, characterized in that the sheaths (20) of the longitudinal threads (15) and the sheaths (21) of the transverse threads (17) are connected to one another at the fastening points (19). 13. Filter package according to claim 11 or 12, -4- „4- Oi characterized in that the covering (20) at least facilitates the fastening of the at least some longitudinal threads (15) to the associated vertices (3; 5) of the filter material (2). 14. Filter package according to one of claims 1 to 13, characterized in that between the grid (13) and the opposite side (4;6) of the filter package (1) there is arranged a sheet-like web (23) covering the entire side (4;6) made of a gas-permeable, fine-mesh or finely cross-linked material.