Filter insert and process for producing it

Details Filter insert and process for producing it Filter insert and process for producing it

1996-06-28

1999-03-30

Spitzer, Robert

Gas separation

With means securing or retaining separating media

Unit or cohesive sheet-like media in flow line or frame

55521, 55527, 55DIG5, 2104935, B01D 2921, B01D 2706

Patent

active

058882626

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The invention relates to a filter insert including a material permeable to fluid and having a number of planar fold walls arranged in a substantially continuous zigzag shape and including depressions and/or elevations stamped into the plane of at least a part of a respective one of the fold walls in order to stiffen the fold walls, the depressions and/or elevations of adjacent fold walls being connected to one another at least partially and being supported on one another.
Filter inserts of the above types are used to remove contamination from a fluid flowing through a filter, particularly air or industrial gasses, but theoretically liquids as well. At present, filter elements consisting of a micro fibre fleece, particularly glass fibres, are predominantly used in air filters.
In order to increase the effective filter area relative to the inflow surface of the air filter which forms a filter element or filter area, the filter medium is folded in a zigzag shape so as to produce a number of folds adjoining one another via fold edges, which are located at an acute angle to the walls of the folds and through which the medium to be purified flows at right angles to the direction of the fold edges.
As a result of the depositing of material, and particularly the settling of larger particles, on the inflow side of the filter, turbulence in the inflowing fluid, slight irregularities in the folds, etc, inhomogeneities may occur in the fluid flow as the fluid flows through the filter, thereby subjecting the fold arrangement to strong mechanical alternating stresses and possibly bringing about deformation of the fold arrangement.
In order to hold the folds at a specified distance from one another and mechanically stabilise the fold arrangement of the filter insert, the folds are therefore provided with projections protruding from the plane of the fold walls, as described for example in U.S. Pat. No. 3,531,920 or, according to another special embodiment, in DE 41 26 126 A1, in such a way that the projections of adjacent fold walls abut on one another and the fold walls support one another. In order that the fold walls are directed at an inclined angle to the incoming fluid, ie. the fold layers are substantially triangular in cross section, the projections must also be approximately triangular or trapezoidal in cross section.
These arrangements have proved suitable for filter inserts with a fold height up to about 100 mm, with relatively tightly packed folds. Beyond this fold height and with larger fold spacings, however, the depth of impression required is so great that, with conventional filter materials, there is the risk of the folds being punched through, thereby unacceptably increasing the number of rejects.
It is also known from DE 40 38 966 to place separate spacers with the same function on the fold walls or to insert said spacers therein. The spacers may be adhesive aggregates, particularly in fibre form, as mentioned as a possibility in the specification referred to above or as illustrated in DE 30 37 019 A1. In addition to acting as spacers, they also have the effect of connecting the fold walls and thus further increasing the rigidity of the filter insert.
The adhesive is applied before the folding of the filter material onto the flat strip, and the fold walls are adhered by the contact of the adhesive threads with one another during the folding operation. This solution is therefore only suitable for very densely packed folds. In addition, the fold layers formed in this way tend to have a meandering configuration in cross section, which does not lead to optimum flow qualities.
DE 39 03 730 A1 describes how an adhesive thread which joins the fold layers together and stabilises them and which may be applied to the edge area after folding, is combined with impressions in the fold walls. This solution results in mechanically very stable filter inserts, but is subject to essentially the same restrictions as the solutions without adhesive in terms of the fold height and fold spacing wh

REFERENCES:
patent: 2784802 (1957-03-01), Bub et al.
patent: 2936855 (1960-05-01), Allen et al.
patent: 2945559 (1960-07-01), Buckman
patent: 2968361 (1961-01-01), Buckman
patent: 3198336 (1965-08-01), Hyslop
patent: 3279615 (1966-10-01), Stokes
patent: 3280985 (1966-10-01), Czerwonka
patent: 3531920 (1970-10-01), Hart
patent: 3633756 (1972-01-01), Buckman
patent: 3716970 (1973-02-01), Stupf et al.
patent: 3799354 (1974-03-01), Buckman et al.
patent: 3871851 (1975-03-01), Neumann
patent: 4268290 (1981-05-01), Barrington
patent: 4452619 (1984-06-01), Wright et al.
patent: 4610706 (1986-09-01), Nesher
patent: 4615804 (1986-10-01), Wright
patent: 4732678 (1988-03-01), Humbert, Jr.
patent: 5028331 (1991-07-01), Lippold
patent: 5053131 (1991-10-01), Lippold
patent: 5066319 (1991-11-01), Lippold
patent: 5066400 (1991-11-01), Rocklitz et al.
patent: 5071555 (1991-12-01), Enbom
patent: 5080790 (1992-01-01), Widmann
patent: 5089202 (1992-02-01), Lippold
patent: 5236480 (1993-08-01), Svensson et al.
patent: 5290447 (1994-03-01), Lippold
patent: 5306321 (1994-04-01), Osendorf

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