U.S. patent application number 09/810630 was filed with the patent office on 2001-09-20 for filter cartridge.
Invention is credited to Fath, Jurgen, Schottmer, Dieter.
Application Number | 20010022069 09/810630 |
Document ID | / |
Family ID | 7635298 |
Filed Date | 2001-09-20 |
United States Patent
Application |
20010022069 |
Kind Code |
A1 |
Fath, Jurgen ; et
al. |
September 20, 2001 |
Filter cartridge
Abstract
A filter cartridge is made of an accordion fold pack folded in a
zigzag-shape. At the end faces (4) of the accordion fold pack,
running parallel to the folds, provision is made for the closing
elements (5) which include stiffening strips (6), partially
covering the accordion fold pack (2), at least on its discharge
side, and sealing elements (7) integrally connected to the
stiffening strips (6).
Inventors: |
Fath, Jurgen; (Weinheim,
DE) ; Schottmer, Dieter; (Dortmund, DE) |
Correspondence
Address: |
KENYON & KENYON
ONE BROADWAY
NEW YORK
NY
10004
US
|
Family ID: |
7635298 |
Appl. No.: |
09/810630 |
Filed: |
March 16, 2001 |
Current U.S.
Class: |
55/497 |
Current CPC
Class: |
B01D 46/10 20130101;
B01D 2265/04 20130101; B01D 2279/50 20130101; B01D 46/521 20130101;
Y10S 55/31 20130101; B01D 2271/02 20130101 |
Class at
Publication: |
55/497 |
International
Class: |
B01D 046/52 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 17, 2000 |
DE |
100 13 301.0 |
Claims
What is claimed is:
1. A filter cartridge comprising: an accordion fold pack folded in
a zigzag shape, the accordion fold pack having end faces running
parallel to the folds, closing elements which include stiffening
strips partially covering the accordion fold pack, at least on a
discharge side of the fold pack, and sealing elements integrally
connected to the stiffening strips, the end faces of the accordion
fold pack being adapted to receive the closing elements.
2. The filter cartridge as recited in claim 1, wherein the
stiffening strips have a sawtooth-like form.
3. The filter cartridge as recited in claim 1, wherein the
stiffening strips are perforated.
4. The filter cartridge as recited in claim 1, wherein the sealing
elements comprise sealing flaps directed toward an intake side of
the accordion fold pack.
5. The filter cartridge as recited in claim 4, wherein the sealing
flaps are bent convexly or concavely in their longitudinal
direction.
6. The filter cartridge as recited in claim 4, wherein a height of
the sealing flaps is at least 10% of a height of the folds of the
accordion fold pack.
7. The filter cartridge as recited in claim 1, wherein the sealing
elements have a hose-type design.
8. The filter cartridge as recited in claim 7, wherein the sealing
elements are made of a slitted, hose-like roll, each of the slit
edges having a stiffening strip connected to it.
9. The filter cartridge as recited in claim 1, wherein the sealing
elements have a U-shaped form and are connected with their free
edges to the stiffening strips, each of the stiffening strips being
positioned on one side of the accordion fold pack.
10. The filter cartridge as recited in claim 1, wherein the
stiffening strips and the sealing elements have a different
strength and/or material density.
11. The filter cartridge as recited in claim 1, wherein the
stiffening strips and the sealing elements are made of different
materials.
12. The filter cartridge as recited in claim 11, wherein one of the
different materials is a nonwoven fabric.
13. The filter cartridge as recited in claim 11, wherein one of the
different materials is a thermoplastic.
14. The filter cartridge as recited in claim 1, wherein the
stiffening strips and the sealing elements are connected to each
other via a bending fold.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a filter cartridge made of
an accordion fold pack folded in a zigzag shape which can be used
in a frame in ventilating systems, air-conditioning systems and the
like. The design of the accordion fold pack and the choice of the
material used for it depends on the filter's technical properties
and the required air throughput.
[0002] From German Patent 195 12 678 C1, for example, a filter
cartridge is known. The filter cartridge in that patent is designed
as an accordion fold pack and made of a thermoplastic heat sealable
nonwoven fabric. A recurring problem with such filters is sealing
it at the frame or housing in which it is set. To solve this
problem, the known filter cartridge offers a combined sealing and
stiffening bracket, covering the end face of the accordion fold
pack. The sealing and stiffening bracket in cross-section, is
shaped like a radical (i.e. {square root}{square root over ( )}).
The sealing bracket has a V-shaped cross-section, open at the inlet
flow side of the medium to be filtered, so that the sealing
bracket, under elastic pretension, lies sealingly against the
housing. This solution produces good results, but requires
additional space at the side. Additional space, during the
filtering procedure, is limited. In addition, under certain edge
conditions, it turned out that mounting a radical-shape designed
sealing and stiffening bracket was a problem.
SUMMARY OF THE INVENTION
[0003] The object of the present invention is to create a filter
cartridge which is simple in its construction, and which can be
inserted into a corresponding frame or housing without difficulty.
The filter cartridge should also have the ability to form a good
seal at its end faces running parallel to the folds.
[0004] In accordance with this object, a filter cartridge built
according to the principles of the present invention has an
accordion fold pack. The accordion fold pack is provided with
closing elements. The closing elements include stiffening strips
partially overlapping the accordion fold pack and sealing elements
which are integrally connected to the stiffening strips. The
stiffening strips are positioned at the end faces of the accordion
fold pack, which run parallel to the folds.
[0005] During continuous production of accordion fold packs folded
in a zigzag shape, the accordion fold packs are cut off to desired
lengths. This produces a need to stiffen the end faces of the
accordion fold packs and provide them with a sealing element. In
order to arrive at the simplified specific embodiment of the
sealing element, the stiffening strips are attached at the
discharge side of the accordion fold pack. The attachment can be
made, for example, using an adhesive or heat sealing procedure,
depending upon which kind of material is planned for the closing
elements.
[0006] In order to influence the flow-through of the filter
cartridge as little as possible by the mounting of the stiffening
strips at the edge region of the accordion fold pack, the
stiffening strips can be developed in a saw tooth manner. It is
also possible to use stiffening strips which are hole punched or
perforated.
[0007] Mounting the stiffening strips on the discharge side of the
accordion fold pack allows the sealing elements to be made of
sealing flaps directed toward the intake side of the accordion fold
pack. The filter cartridge is dimensioned so that the sealing
flaps, with their areas adjoining the stiffening strips, fit into
an insert opening of a frame or housing, as the case may be, while
their areas lying farther out project beyond the insert opening,
and are fitted into the opening with a slight press. Their end
edges then lie sealingly against the housing wall. Preferably, the
height of the sealing flaps is less than the height of filter
folds, so that their outer edge can lie sealingly against the
housing wall, which, as a general rule, has the same height as that
of the folds. On the other hand, the sealing flaps should be
dimensioned so that their height is at least 10% of that of the
folds, so as to be able to cover a sufficient tolerance between the
filter cartridge and the housing.
[0008] Depending on the available frame and the material used for
the sealing elements, the sealing flaps can be bent convex or
concave in their longitudinal direction. This allows higher
pressure differences at the filter cartridge and the use of soft
materials for the sealing elements. The existing pressure
difference can then reinforce the sealing effect.
[0009] The sealing elements can also take the form of a hose in an
exemplary embodiment. In the simplest solution, the sealing flap,
rolled into a hose, can be joined at its outer edge to the
stiffening strip. However, for technical production reasons, the
sealing elements preferably are made of a slitted, hose-like roll,
having a stiffening strip joined at each slit edge. When combining
this with the accordion fold pack, the two stiffening strips can
then be connected to each other.
[0010] In another exemplary embodiment the sealing elements are
U-shaped, with their free edges joined to stiffening strips. The
stiffening strips are positioned both at the intake side and at the
discharge side of the accordion filter pack. This embodiment also
allows the flow direction to be changed.
[0011] In one embodiment, the stiffening strips and the sealing
elements are made of a material of the same strength. They are
connected to each other via a connecting fold. The stiffness of the
material is chosen so that the filter cartridge is held in the
housing or frame in a force locking way. The bending fold permits a
minor degree of bending of the sealing element with respect to the
stiffening strips.
[0012] It is also possible to design a closing element so that the
stiffening strips and the sealing elements have a different
strength and/or material density. This permits the filter to be
adapted to a wide range of predefined conditions.
[0013] It is also possible to form the stiffening strips and the
sealing elements of different materials. Since the accordion fold
packs are predominantly made of nonwoven fabrics, a nonwoven fabric
is an obvious example material for the closing element. This allows
the possibility of representing the filter as being made of uniform
components. It is also possible to use thermoplastics as a working
material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention is explained in detail below, using
exemplary embodiments represented in the drawings.
[0015] FIG. 1 shows a cross-section through a filter cartridge;
[0016] FIG. 2 shows the filter cartridge as in FIG. 1, shown in
perspective view;
[0017] FIG. 3 shows a filter cartridge with sawtooth-like developed
stiffening strips in the perspective view;
[0018] FIG. 4 shows a filter cartridge with perforated stiffening
strips;
[0019] FIG. 5 shows a section of a filter cartridge in
cross-section with a convexly bent sealing flap;
[0020] FIG. 6 shows a section of a filter cartridge in
cross-section with a concavely bent sealing flap;
[0021] FIG. 7 shows a filter cartridge with a sealing element made
from a hose-like roll, in cross-section;
[0022] FIG. 8 shows a filter cartridge in cross-section with a
sealing element as a hollow body and
[0023] FIG. 9 shows a filter cartridge in cross-section with a
U-shaped sealing element.
DETAILED DESCRIPTION OF THE INVENTION
[0024] FIG. 1 shows a cross-section of a filter cartridge 1 made of
a zigzag-shape folded accordion fold pack 2. The filter cartridge 1
is enclosed on both sides by a seal 3. At an end face 4 of the fold
pack 2, closing elements 5 are provided. The closing elements 5
include stiffening strips 6 and sealing elements 7 integrally
connected with the latter. The stiffening strips 6 are fixedly
connected to the edge region of the accordion fold pack 2, by, for
example, heat sealing or an adhesive. An arrow 8 indicates the
direction of air flow through the filter cartridge. The filter
cartridge 1 is positioned in a housing, not shown in greater
detail, and the sealing elements 7 are then lightly pressed in the
direction of the accordion fold pack 2. In order to simplify the
movement of the sealing elements 7, a bending fold 9 is provided
between the stiffening strips 6 and the sealing elements 7. Such a
filter is very simple in its construction and fulfills all the
necessary requirements.
[0025] FIG. 2 shows the filter cartridge 1 in perspective view. The
stiffening strips 6 are located on the discharge side 10 of the
filter cartridge 1. The sealing elements 7 run parallel to the end
faces 4 of the accordion fold pack 2. A seal 3 covers the side
surfaces of the accordion fold pack 2. The air stream to be
filtered is indicated by an arrow 8.
[0026] In FIG. 3, the construction of the filter cartridge 1 is
similar to the filter construction of the previous figures, except
the stiffening strips 6 are designed sawtooth-like. In this
exemplary embodiment, the sawteeth 11 go all the way to the bending
fold 9.
[0027] A further possibility of making the stiffening strips 6 as
air-permeable as possible is illustrated in FIG. 4. In FIG. 4, the
stiffening strips 6 of the filter cartridge 1 are provided with
holes 12.
[0028] In FIG. 5, a section of the filter cartridge 1 is shown
enlarged to illustrate in cross-section the positioning and design
of the closing element 5. The stiffening strips 6 are positioned on
the edge of the accordion fold pack 2, on the discharge side 10 of
the filter cartridge 1. The sealing flaps 7, which are aligned
concave to an inlet side 13 of the accordion fold pack, are
attached to the stiffening strips 6. The stiffening strips 6 and
the sealing flaps 7 are made of different materials, which is
indicated by the crosshatching. However, the two parts are
integrally connected to each other. The stiffening strips 6 and/or
the sealing flaps 7 can be made of nonwoven fabric, for example
those made of polyester, propylene or polyethylene fibers or
filaments. Instead of nonwoven fabrics other planar materials can
be used. For example, foils of polypropylene, polyethylene, ABS,
PU, TPE or sheet metal made of metallic materials, such as aluminum
are suitable.
[0029] FIG. 6 shows another exemplary embodiment which is similar
to the embodiment shown in FIG. 5. In the embodiment of FIG. 6,
however, the sealing flaps 7 are designed to be convex to the
intake side 13 of the accordion fold pack 2. This makes for a
stronger lip seal by the edges 14 of the sealing flaps 7 at the
housing wall.
[0030] In all the specific embodiments of FIGS. 1 to 6, the height
h of the sealing flaps 7 is chosen to be less than the height H of
the folds of the accordion fold pack 2. This provides as favorable
as possible a sealing at the housing wall, which is not shown in
greater detail. However, the height h of the sealing flaps is at
least 10% of the height H of the folds.
[0031] In FIG. 7, the attachment of a sealing flap 7, designed
hose-like, is shown in cross-section. The sealing element 7 is
formed from a slitted, hose-like roll 15, and the slit edges 16 and
17 of the roll 15 are each connected to a stiffening strip 6, 6'.
The stiffening strips 6, 6' are fixedly connected when they are
fixed to the accordion fold pack 2, for instance, by heat
sealing.
[0032] Instead of the roll 15, another hollow form can also be
selected for the sealing element 7. Thus, FIG. 8 shows in
cross-section a triangular design of a hollow form. This is
advantageous when great stiffness is desirable for the closing
element 5. The concavely bent wall 18 of the hollow form can be
regarded as a sealing flap which is strengthened in its stiffness
by the walls 20 and 21 standing at an angle to one another.
[0033] Another embodiment of a closing element 5 is shown in FIG.
9. In this embodiment the sealing element 7 is U-shaped, and its
free edges 16 and 17 are connected to first and second stiffening
strips 6, 61. The first stiffening strip 6 is affixed to the upper
side of accordion fold pack 2, as seen in the drawing, while the
second stiffening strip 6' lies on the lower side. With this design
of the sealing element 7 the flow-through direction of the filter
cartridge 1 is of subordinate importance, so that this filter
cartridge 1 can be installed the other way round in the housing or
frame.
* * * * *