ELEMENT FILTRANT POUR LE GAZ

A GAS FILTER ELEMENT

Abrégé français

Des première et seconde couches (15) pratiquement identiques d'un matériau rigide comprennent chacune une pluralité de zones dont chacune est délimitée par des lignes de pliure parallèles (1, 2). Les couches sont composées d'éléments (10) formant paroi, s'étendant entre la ligne de pliure (2) et une ligne de pliure (3), ainsi que d'éléments (11) formant paroi s'étendant entre la ligne de pliure (3) et la ligne de pliure (1), chaque élément paroi (11) contenant une pluralité d'ouverture (4) espacées dans le sens desdites lignes de pliure. Afin de former l'élément de filtration, les deux couches (15) sont réunies, le long de chaque ligne de pliure (2) à la ligne opposée (1), ce qui permet d'obtenir une série de chambres (5). L'écoulement d'air non purifié pénètre dans ces chambres par les ouvertures (4) pratiquées dans une première couche (15) et sort, sensiblement purifié, par les ouvertures (4) pratiquées dans la seconde couche (15).

Abrégé anglais

2141947 9428997 PCTABS00034
First and second substantially identic layers (15) of rigid
material each comprise a plurality of zones, each zone being defined
by parallel fold lines (1, 2). The layers are formed of wall
elements (10) extending between fold line (2) and a fold line (3), and
of wall elements (11) extending between fold line (3) and fold
line (1), each wall element (11) containing a plurality of
openings (4) spaced along the direction of said fold lines. To form the
filter element the two layers (15) are joined together along each
fold line (2) to the opposite fold line (1), thus providing a
series of chambers (5). The unpurified air flow enters these
chambers through the openings (4) of a first layer (15) and exits
substantially purified through the openings (4) of the second layer
(15).

Revendications

WO 94/28997 4 PCT/EP94/01392
CLAIMS
1. A gas filter element formed by at least two juxtaposed layers,
each of said two layers comprising a plurality of zones, each defined by a
first pair of fold lines, each zone including openings and intermediate
fold lines substantially parallel with the said first pair, wherein the two
layers are each deformed along said fold lines and joined together along
contiguous fold lines thereby forming chambers between the layers,
characterized in that the two layers are substantially identical in shape
and size.
2. A gas filter element according to claim 1, wherein the openings
are between two intermediate fold lines.
3. A gas filter element according to claim 1 or claim 2, wherein
the cross-section through the chambers is substantially a parallelogram.
4. A gas filter element according to anyone of the preceding
claims, wherein the layers are made of a substantially rigid material.
5. A gas filter element according to claim 4, wherein the rigid
material is treated or untreated paper or a plastics material.
6. A gas filter element according to anyone of the preceding
claims, wherein at least one additional layer is attached to said two
layers so as to provide at least one further filter element.

Description

wo 94/28997 21419 4 7 PCT/EP94101392
A AS FILTERELEMENT
The invention relates to a gas filter element formed by two juxtaposed
layers, which is particularly suited to removing particles entrained in a
gas stream.
It is often necessary to purify air in a room or other enclosed space,
which is loaded with suspended particles, such as removing paint dust
from air in a paint spray booth. Methods and apparatus for cleaning gases
for recycling or discharge is an area where a large amount of research
has been undertaken and for this purpose numerous filters have been
provided. However, these filters are prone to fast clogging of the filter
elements.
GB 917669 teaches a gas filter which comprised h~o layers of material
which are each folded in a zig-~ag manner. At alternate turning points of
the zig-zags of each layer, the two layers are joined. As one layer is of
greater area than the othe! layer, chambers are formed between the
layers. Openings are provided through each of the layers so that gas
passing through the filter is provided with a distorted flow and
suspended particles removed.
The present invention seeks to provide a filter element that is cheaper to
manufacture and improves upon the filtration proper~ies of the known
filters .
According to the present invention, there is provided a gas filter element
formed by two juxtaposed layers9 each layer comprising a plurality of
zones, each defined by a first pair of fold lines, each zone including
openings and intermediate fold lines substantially parallel with the said
first pair, wherein the two layers are each deformed along said fold
Iines and joined together along contiguous fold lines thereby forming
chambers between the layers, characterized in that the two layers are
substantially identical in shape and size. `

WO 941289D7 ~9~1 PCT/EI'94101392
The filter element provided by the present invention is far simpler to ~-
manufacture, since it is necessary to manufacture only one design of
layer. The filter element is subject to low degrees of clogging of the
element. Aiso, this filter element provides a high degree of filtration.
Preferably, the cross-section through the chambers i5 substantially a
parallelogram. '` ~' ,
In caees where very high degrees of filtration are required, further
layers of material may be attached to the filter to act as further filter
elements.
Normally, the layers comprise a substantially rigid material. In one
embodiment of the invention the material is paper, treated or untreated.
Alternatively, the material may be a plastics material. -
The invention will now be described with reference to the accompanying
drawings, in which:
Fig. 1 shows cross-section through a folded layer of a first embodimentof the filter element according to the invention;
Fig. 2 shows a view along the line A-A of Fig. 1;
Fig. 3 sh~ws a front view of a layer from B in Fig. 1; and
Fig. 4 shows part of a filter element according to the first embodimentof the invention.
Figures 1 to 3 show a layer 15 of rigid material. The layer 15 is divided
into zones by pairs of parallel fold lines 1 and 2. Each zone is sub-
divided into two pairs of wall elements 10 and 11 by parallel fold lines
1, 2, 3. Each of the wall elements 10 extends between a fold line 2 and a
fold line 3. Each of the wall elements 11 extends between a fold line 1
and a fold line 3. Each wall element 11 contains a plurality of openings 4.

WO 94/28~g7 3 2~ A~9 4 PCTIEP!~4/01392
The layer 15 is folded in a zig-zag manner about each fold line 1 and 2, -
forming a concertina-shaped layer 15. The layer is also folded about fold ~ -
lines 3. 3'~
.'
To form the filter element, as shown in Fig. 4, two substantially
identical layers 15 are joined together along each fold line 2 to the
opposite fold line 1. The folding of the two layers 15 is in opposite
directions with regard to the Y axis. This forms chambers 5 bounded by a
wall element 10 and a wall element 11 of each of the two layers 15.
In use, the unpurified air stream enters a chamber ~ of the filtsr element
through the openir,gs 4 of one layer 15. Subsequently, the air stream is
deflected by wall elements 10, 1 1. The air stream exits, substantially
purified, through the openings 4 of the other layer 1~.
As will be appreciated, different designs of the filter element of this
inYention can be easily envisaged having more or less individual wall
elements defining a chamber. It is essential that a high degree of
symmetry be maintained so that the manufacturing process is kept cost
efficient.
It should be noted that throughout this specification, the word "fold"means a deformation, and the term "fold line" means a line about which a
material is deformed. In alternative manufacturing processes, such as
when the filter is made from piastics material, each element may b~
ex~ruded or moulded. The fold lines would then relate to an area about
which the element is deformed. It must also be noted that throughout
this specification, the word "openings" means "perforations".

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