FILTER ELEMENT FOR COLLECTING DUSTS

FILTRE POUR DEPOUSSIEREUR

English Abstract

ABSTRACT
A filter element is described which serves to
collect dusts from gases or air and which consists of metals,
alloys or plastics and is thin-walled and similar to a film
or sheet and has a wall thickness from 0.05 to 2 mm and has a
large number of regularly arranged holes which differ in shape
and size. The holes have a hydraulic diameter from 0.01 to 1 mm
and the area covered by the holes is 30 to 90% of the front
surface area of the filter element.

Claims

The embodiments of the invention in which an
exclusive property or privilege is claimed are defined as
follows:
1. A filter element for collecting dusts from
gases or air, which filter element consists of metals,
alloys or plastics and is thin-walled and similar to a film
or sheet and has a wall thickness from 0.05 to 2 mm and has
a large number of regularly arranged holes which differ in
shape and size, characterized in that the holes have a
hydraulic diameter from 0.01 to 1 mm and the area covered by
the holes is 30 to 90% of the front surface area of the
filter element.

Description

13219~9
DESCRIPTION
This invention rel3tes to a filter element for
collecting dusts from gases or air, which filter element con-
sists of metals, alloys or plastics and is thin-walled and si-
milar to a film or sheet and has a wall thickness from O.OS to
Z mm and has a large number of regularly arranged holes which
differ in shaoe and size.
Published 5erman Application 3,134,148 discloses
a filter element which is of the kind described first herein-
before and in which the holes are 5 to 200 ~m in diameter and
the ratio of the hole spacing to the hole diameter is between
4:1 and 5:1. Whereas the known filter element has been used to
collect dust at a high rate, an undesirably fa~t rise of the
pressure drop has been observed in some cases during the filter-
ing operation and has required a cleaning of the filter ele-
ment after short intervals of time. For this reason it is an
object of the invention to provide a filter element which is
of the kind described first hereinbefore and which will collect
dust at a high rate and can be oPerated with a pressure drop
that is as constant as possible for the longest possible time.
The object underlying the invention is accomplished
in that the holes have a hydraulic diameter from 0.01 to 1 mm
and the area covered by the holes is 30 to 90% of the front
surface area of the filter element. It has surprisingly been
found that a filter element formed with irregularily shaped
holes, ~hich may be, e.g., lens-shaped or rectangular or
.

- 2 ~ 13219~9
star-sha~ed, will collect dust at a high rate in conjunction
with an only slowly rising pressure drop if said filter ele-
ment has the features in accordance with the invention.
The filter element designed in accordance with
the invention may be used as a flat sheet or a tube or a bag.
The fllter element i9 cleaned in known manner in that it is
rapped and/or in that a gas is passed thraugh the filter ele-
ment in a reverse stream which Tay be cantinuous or pulsed.
Even fine dusts are removed by the filter element from the raw
gas to such a high degree that the pure gas contains less than
10 mg/sm3 dust. The danger of a clogging of the filter ele-
ment may be reduced by the prDvision of non-circular holes so
that a high permeability for the gas to be dedusted is main-
tained and the pressure drop rises only slowly even in a pro-
longed time.
The hydraulic diameter is defined as the quotient
of four times the cross-sectional area of a hole which con-
stitutes a flow passage and the peripheral length of said hole.-
-,. -
,. . .