DE4345121A1 - Concertina filter element - Google Patents

Abstract

Filter element, pref. for an air filter, is in the form of a cloth folded in a zigzag manner. The cloth is indented in places (3) so that the convex edges of the indentations in adjacent folds face each other and can then be connected by an applied layer (6) of adhesive, thereby providing a stiffening, i.e. form retention, of the element. The adhesive (6) is applied in varying thicknesses. Also claimed is the process for achieving this.

Description

The invention relates to a filter insert according to the upper Concept of claim 1 and a method of manufacture such.

Filter inserts specific in the preamble of claim 1 graced type serve to remove impurities from a through  a filter flowing fluid (especially air or technical gases, but basically also liquid separations). Air filters are becoming present predominantly filter elements used, which consist of a Micro-fiber fleece, in particular made of glass fibers.

The effective filter area compared to the inflow area of a filter element or a filter area To enlarge the air filter, the filter medium is zigzag folded in a shape so that a number of over fold edges contiguous folds are created, which in one acute angle to the walls of the fold and at the same time across to the direction of the fold edges of the me to be cleaned flow through dium.

Due to the material deposition - especially the waste larger particles - on the inflow side of the fil ters, vortex formation in the incoming fluid, slight Irregularities in folding etc. occur when passing through flow of the filter to inhomogeneities of the fluid flow, the fold arrangement of a strong mechanical change Expose yourself to stress and deformation of the folds can bring about order.

To keep the folds at a defined distance from each other and the pleat arrangement of the filter insert mechanically stabilize the wrinkles, for example - such as in US 3,531,920 or in a special further Education described in DE 41 26 126 A1 - such with from projections protruding from the plane of the fold walls see that the projections of adjacent fold walls  de abut each other and the fold walls against each other support. So that the fold walls to the incoming fluid can be inclined, d. H. the pleats have an approximately triangular cross section Protrusions approximately triangular or trapezoidal cross have cut.

These arrangements are for filter inserts up to approximately 100 mm Proven fold height with a relatively tight fold pack. Jen on the part of this fold height and with a larger fold distance However, the required embossing depth is so great that at the usual filter materials the risk of imprinting conditions exist and thus the reject rate in unacceptable would increase barely.

From DE 40 38 966 it is also known to have separate spacing holder with the same function on the fold walls zen or insert into this. The spacers can - as in the aforementioned document as a possibility mentioned or also performed in DE 30 37 019 A1 - adhesive fabric aggregates, especially in thread form. These have the Fal in addition to the spacer effect and thus increase the stone ability of the filter insert.

The adhesive is applied before the Filterma is folded terials on the flat sheet, and gluing the folds walls occurs through the contact of the adhesive threads different when folding. This solution is therefore only for very dense fold packs suitable. They also have on this way, pleated layers formed more meandering  Cross-sectional shape, which is not optimal flow characteristics result.

DE 39 03 730 A1 describes that the Faltenla bonding and stabilizing adhesive fabric thread that folds onto the edge area can be worn with embossing in the fold walls is combined. This solution is mechanically very stable le filter inserts, but is achievable in terms of Ren fold height and the fold distance essentially the subject to the same restrictions as the solutions without Adhesive application.

DE 42 06 407 describes that the fold edge be rich of an already folded filter material web with egg is covered with a fine web of adhesive threads in order to to connect the folds together and the filter insert to stabilize. This solution is also for larger wrinkles distances are no longer practical because the fine adhesive do not spin apart a sufficiently stable connection other fold edges can produce and the Ge spun threads (especially when applied from below to a "sagging" in the manufacturing process overhead fold web) and no longer take a defined position to the fold edges men.

From EP 0 377 419 A1 an arrangement is known in which by forming one in the crown as well as in the sole area localized adhesive aggregates the fold wall arrangement of different sizes (larger in the crown area, in the Sole area smaller) the gluing of fold walls in  in a way that approximates triangular fold cross section arises. Larger folds stands and thus heights are in this way not feasible because of the very voluminous adhesive aggregates would be required, the effective filter area would greatly reduce che.

The invention is therefore based on the object of a fil use of the generic type, of its structure forth the realization of filter inserts with great height and / or large fold spacing allows, as well as a Ver drive to manufacture this filter insert.

This task is carried out by a filter insert with the Merk paint the claim 1 or a method with the features of claim 8 solved.

The invention includes the idea that at large Wrinkle spacing or large fold height (with thereby compulsory common areas with large fold spacing) required great height of the spacers between the folds through a combination of embossed and spacer created by applying to the material to realize. This requires that the as - such be knew - apply adhesive at least in the area where the interconnected fold walls large distance have a significant contribution to the thickness or height of the Spacer must provide, and further means that the Thickness of adhesive over the length of a fold wall - d. that is, from the sole or the "fold tip" to the fall peak should not be constant.  

This is particularly feasible in that the ent speaking adhesive layers in the same direction as the cross narrowing of the fold in question towards the "pleat tip" are continuously thinning.

It can also be realized in that the correspond layers of adhesive in the direction of the longitudinal extension of the wells or surveys supporting them are broken and one of the "fold tips" neighboring Ab cut is thinner than a cut away from it Section. The adhesive can be applied within the two (or more) separate areas or adhesive islands have a constant thickness, so a continuous change in cross section here is not required.

In a further embodiment, can also exclusively in the areas where the fold walls are large apart have an applied (adhesive) spacer be provided while in the narrower areas of the Fal no adhesive is applied or the adhesive fabric has no appreciable thickness by the applied Quantity is approximately such that it essentially in the Filter material penetrates.

The total height of the spacers can be one be built up that the height of the embossed in the material Indentations or elevations in the direction of their longitudinal stretch is substantially constant, d. H. which according to the Zigzag shape of the fold cross section required height change exclusively from the change in thickness of the wearing layer results.  

On the other hand, the structure can also be such that the Height of the depressions or elevations in two fold walls those who support each other towards the fold edges connecting these fold walls together decreases. So both the impressions and the applied layer for the required change in height of the Spacers at.

The configurations mentioned are both for filters suitable sets in which the folding is a body of the Shape of a cuboid, for example for use for air filters in ventilation and air conditioning systems. you are but also suitable for cylindrical filter inserts, at which the folding is a body shaped like a hollow cylinder, for example for use in air filters for motor vehicles.

The method according to claim 9 can according to the Ausge Events of the structure of the spacers designed be that per unit length in the direction of the longitudinal stretching of the adhesive layer of variable thickness supporting depression or elevation applied adhesive amount towards the imprint that the future "Wrinkle tip" marked, is controlled decreasing.

Alternatively or in combination with this, the adhesive application of fabric in the direction of the longitudinal extension of it deepening or survey at least once be broken and the per unit length of the filter mat amount of adhesive applied beyond the bottom break towards the "fold tip" markie  imprinting should be chosen lower than on this side the interruption, d. H. in the wide open part of the fold, where the spacer must be higher.

A combination of both options can look like that one after the other (through several nozzles or possibly also through Repeatedly pass one and the same nozzle over the area) a continuous and on or under this is followed by an interrupted order. After this The principle is to create a variety of spacer profiles bar.

For filter performance, it is beneficial if only one The smallest possible area of the filter material with the Auf base layer (the adhesive) is covered.

This can be achieved by clearing the order exactly defined, preferably essentially linear, d. H. with very less compared to the length of the layer Width. This implies the choice of an appropriate one Adhesives - with be matched to the filter material wetting properties - and the correct setting of a pasty to jelly-like consistency ahead such that at least a broad run on the filter material hardening is avoided, but preferably a spatial one precisely limited adhesive aggregate on the filter material can be applied.

The applied per unit length of filter material Amount of glue can - as a basic possibility - on the variation of per time unit from one up  Carrying device on the continuous web of material given amount of adhesive can be changed. For variation the amount of adhesive per unit time can be a corresponding Control the cross-section of the outlet opening of the on carrying device are made, d. H. specifically at An closer to those who notice the future "fold tips" Fold lines whose cross-section is reduced and at removal of these can be enlarged.

In addition or as an alternative to this, the Amount of adhesive per unit of time a corresponding tax tion of the outlet pressure from the application device be taken.

Another - again with the other options binaryable - possibility is that about partial one order is enough for the length of the spacers done in several layers one above the other. This can be like in turn through multiple nozzles or multiple passes chen of the areas concerned with one and the same nozzle respectively.

Finally - also in combination with one or more of the other options - the pro Length unit of the filter material web applied adhesive amount of substance by varying the relative speed between the material web and the outlet opening of a Application device can be changed.

It should be noted that in the foregoing all under one material permeable to the fluid  Filterma usual or usable for certain fluids materials, especially nonwovens made of cellulose, glass, Mineral or ceramic fibers, fine-mesh fabrics with or without impregnation etc. and under adhesives for cohesive connection of such materials other usable substances, especially adhesives in narrower sense, but also thermo adhering to the filter material to understand plastic or foam materials or similar are.

Under an essentially zigzag, continuous folds are also included, where the fold cross-section is perpendicular to the folds edges are roughly trapezoidal or the fold edges become blurred det.

Further advantageous developments of the invention are in the subclaims or are identified below along with the description of the preferred embodiment the invention with reference to the figures. It demonstrate

Fig. 1 is a perspective schematic diagram of a Fil tereinsatzes according to an embodiment of the invention,

FIGS. 2a to 2c are schematic cross-sectional views of the folding arrangements of filter elements (perpendicular to the fold edges) according to embodiments of the invention, and

FIGS. 3a and 3b are schematic cross-sectional views of folding assemblies (parallel to the fold edges) according to embodiments of the invention.

Fig. 1 shows a highly simplified representation of an approximately cuboid Fil ter insert 1 from a glass fiber filter fleece 2 with synthetic resin impregnation, the one-sided embossed, bead-like depressions 3 and with (slightly rounded) upper and lower Folded edges 4 a and 4 b are folded approximately in a zigzag shape, so that the impressed recesses 3 in mutually adjacent fold walls 5 face one another. The depressions or beads 3 have a towards the lower fold edges 4 b, ie with increasing opening width of the folds, increasing height.

The fold spacing of the fold are so large (to achieve certain application parameters) that the Schei telflächen 3 a opposing wells 3 do not touch each other.

On each of the apex surfaces 3 a is applied in the direction of the lower fold edges 4 b thicker adhesive layer 6 . The adhesive layers Einan the opposed crest surfaces 3 a are connected to each other, whereby the respective opposite Vertiefun gen 3 and thus the corresponding fold walls 5 are fixedly connected to each other (the adhesive substance in the cured state) and thus the filter insert 1 is mechanically stiff.

Fig. 2a shows a cross-sectional view of the Faltenan arrangement of the filter insert shown in Fig. 1, in which the increase in height of both the recesses 3 and the adhesive layers 6 in the direction from the upper to the lower fold edges can be seen very clearly.

Fig. 2b shows an alternative embodiment, in which in a similar arrangement to Fig. 2a, the fold walls as walls 5 'with their longitudinal extension having substantially constant height beads 3 ' are formed, while the increase in the thickness of the adhesive layers 6 'from the top Fold edge area 4 a 'to the lower fold edge area 4 b' here - with approximately the same fold angle - is more pronounced than in the arrangement according to FIG .

Fig. 2c shows a filter element 1 '' according to another imple mentation form, in which the cross-section of the folding is trapezoidal in such a way that between successive folding tenwalls 5 '' each have two fold lines 4 a '' (upper Faltenkan th) or 4 b '' (Lower fold edges) are provided. The fold walls 5 '' each have embossed beads 3 '' which extend from the upper fold edges 4 a '' to the lower fold edges 4 b '' and have constant height over this extension. In the upper part, the beads 3 '' each have a relatively small adhesive point 6 a '', and near the lower, the lower fold edges 4 b '' adjacent, they end - corresponding to the larger fold distance here - a much more voluminous, hemispherical adhesive fabric aggregate 6 b ''. The individual adhesive layers 6 a '' and 6 b '' on the beads 3 '' adjacent fold walls are each fused together, so that the fold walls 5 '' are firmly connected.

Fig. 3a shows a cross-sectional view of a folding, folding walls 5 in the illustrated, in contrast to in Fig. 1 fold '''are provided, each on both sides beads 3 a''' and 3b ''', and therefore recesses and protrusions, exhibit. Each of the elevations and depressions 3 a '''and 3 b''' carries an adhesive layer 6 ''', with the adhesive layers being connected to each other directed elevations or depressions.

Fig. 3b shows a modification of this arrangement in which the beads 3 a '''' and 3 b '''' in the fold walls 5 '''' are profiled such that they have a central longitudinal groove 6 a '''' , in which an adhesive thread 6 '''' is of relatively small width and with a precisely defined, approximately circular cross-section. Here is only a glue application - just in the form of thread 6 '''' - provided to connect facing beads.

In an arrangement according to FIG. 3, the fold walls are connected on both surfaces to the adjacent fold wall and are supported against it, and the filter element is thus stiffened even more than in the arrangements according to FIGS. 1 and 2.

The arrangement according to Fig. 3b with profiled beads offers the advantage that the adhesive is applied with a small and precisely defined lateral extension, so that smearing on the filter material is avoided and the effective filter area can be maximized.

The invention is not restricted in its implementation on the above-mentioned embodiments. A lot is more - especially with regard to the geometry and the Combination of impressions in the filter material and Application layers on this - a variety of variations  conceivable which of the solution shown also fundamentally different execution use.

Claims (17)

1. Filter insert ( 1 to 1 '') for a fluid filter, in particular for use in ventilation technology, the number of pleated walls arranged in an essentially zigzag, continuous fold ( 5 to 5 '''') from permeable to the fluid Material ( 2 ) with recesses ( 3 to 3 ''; 3 a '''; 3 a'''') or elevations ( 3 b'''; 3 b ''') embossed in the plane of at least some of the fold walls ') For stiffening the fold, the Ver recesses and / or elevations of adjacent fold walls at least in sections via an adhesive layer ( 6 ; 6 '; 6 a '', 6 b ''; 6 '''; 6 '''') are interconnected and are supported against one another, characterized in that at least some of the adhesive layers ( 6 ; 6 '; 6 a''; 6 b''; 6 '''; 6 '''') one in the direction of the longitudinal extension of the Indentations or elevations and thus in to the fold n edges of the fold in a substantially vertical direction has a non-constant thickness. 2. Filter insert according to claim 1, characterized in that an adhesive layer ( 6 ; 6 ') with non-constant thickness in the same direction with the cross-sectional narrowing of a fold in the direction of the fold edge ( 4 a; 4 a') is continuously thinner the folds interconnected via the adhesive layer ( 5 ; 5 ') have in common. 3. Filter insert according to claim 1, characterized in that an adhesive layer ( 6 a '', 6 b '') with a non-constant thickness in the direction of the longitudinal extension of the recess ( 3 '') or elevation is interrupted and one of the Folded edge ( 4 a ′ ′), which the fold walls ( 5 ′ ′) connected to one another by the adhesive layer have in common, adjacent section ( 6 a ′ ′) is thinner than a lying section ( 6 b ′ ′) removed from this fold edge. . 4. Filter insert according to claim 1, characterized characterized in that an adhesive layer with significant height only in that area of folding is provided in which the fold walls are at a large distance from have each other. 5. Filter insert according to one of the preceding claims, characterized in that the height of the depressions ( 3 '; 3 '') or elevations in the direction of their longitudinal extent is substantially constant. 6. Filter insert according to one of claims 1 to 4, characterized in that the height of the recesses ( 3 ) or elevations in two fold walls ( 5 ), which are supported against each other, in the direction of the fold edge connecting these fold walls ( 4 a) decreases. 7. Filter insert according to one of the preceding claims, characterized in that the folding device spans a body in the shape of a cuboid ( 1 ). 8. Filter insert according to one of claims 1 to 6 characterized in that the Fal tion on a body in the form of a hollow cylinder tense. 9. A method for producing a filter insert ( 1 to 1 '') according to one of the preceding claims, in which a web of the fluid-permeable material ( 2 ) with the location of fold edges ( 4 a to 4 a '', 4 b to 4 b '') is provided with predetermined impressions and in the plane ne at least part of future fold walls ( 5 to 5 '''') depressions and / or elevations ( 3 to 3 ''; 3 a ''', 3 b'''; 3 a '''', 3 b '''') are stiffened to stiffen the fold, at least in sections at least one of the mutually facing recesses and / or elevations at least sections of an adhesive layer ( 6 ; 6 '; 6 a'', 6 b''; 6 ''', 6 '''') is applied and the material web is folded on the embossing forming the fold edges, whereby the depressions or elevations on the respective (n) Adhesive layer (s) are connected to each other n and support each other, characterized in that the amount of adhesive applied to the material web per unit length is controlled in such a way that at least some of the adhesive layers ( 6 ; 6 ′; 6 a '', 6 b ''; 6 ′ ′ ′; 6 '''') receives a variable thickness in the direction of the longitudinal extent of the recess or elevation carrying it. 10. The method according to claim 9, characterized characterized in that the per unit length for an adhesive layer with not constant thickness in Rich tion of the longitudinal extent of the depression carrying it or survey applied amount of adhesive towards an impression, the one two over the respective Folded walls to be bonded together common fold edge predetermined, decreasing controlled becomes. 11. The method according to claim 9, characterized in that the application of adhesive for an adhesive layer ( 6 a '', 6 b '') with a non-constant thickness in the direction of the longitudinal extent of the bearing it Ver ( 3 '') or survey at least once is interrupted and the amount of adhesive applied per unit length beyond the interruption in the direction of an embossment that predetermines a fold edge ( 4 ′ ′) that is to be connected to one another via the respective adhesive layer ( 5 ′ ′), is smaller than this side of Interruption. 12. The method according to any one of claims 9 to 11, characterized in that the adhesive material application essentially linear, d. H. with opposite the length of the adhesive layer of very small width, he follows. 13. The method according to any one of claims 9 to 12, characterized in that the per country unit of material applied the variation of the per time unit from an order direction of adhesive output is changed. 14. The method according to claim 13, characterized characterized in that to vary the adhesive amount of substance per unit of time a corresponding control the cross-section of the outlet opening of the order device tion is made. 15. The method according to claim 13 or 14, characterized characterized in that to vary the adhesive amount of substance per unit of time a corresponding control of the outlet pressure from the applicator men will. 16. The method according to any one of claims 9 to 15, characterized in that on the Formation of the adhesive layer provided in  part of its longitudinal extension with several adhesives are sluggish. 17. The method according to any one of claims 9 to 16, characterized in that the per country quantity of adhesive applied Variation of the relative speed between the mate rialbahn and the exit opening of an order queue tion is changed.