Product Function; Main Filtration; Control Filter; Explosion Protection - Nederman FlexFilter EX Manual De Instrucciones

Product function

Main Filtration

The filtration process is described in the following step
1-5 (see picture no . 5) .
1 . The inlet module separate coarse particles .
2 . The coarse particles pass the cone .
3 . The coarse particles fall down into the bin .
4 . Fine dust particles follow the up-going air flow
through the filter unit. The particles are separated
on the outside surface of the filter bags. A long
spiral spring in each filter bag keeps it from flatten-
ing as air passes through the bag from outside to
inside .
5 . The filtered air leaves the collector.
6 . The filtered air continuous through the control filter.
The pressure drop increases as more fine dust settles
on the filter bags. During filter cleaning, part of the dust
is dislodged and falls down into the collecting module .
It is not desirable to dislodge all the dust . A certain
quantity of fine particles on the filter bags improves
particle separation compared to using clean bags .
Different kinds of dust have widely different properties.
Some kinds are easily cleaned off the filter bags while
others require more powerful cleaning .
FlexFilter EX with standard filter cleaning uses its own
vacuum to generate a short blast of air backwards
through the filter bags. A compressed air cylinder in
the top module opens a disc valve so that atmospheric
air can rush into the collector to neutralize the vacuum
stored inside the collector . The higher the vacuum and
the larger the connected piping system, the more air
will flush backwards through the filter bags and the
cleaning will be more effective.

Control filter

The FlexFilter EX is equipped with a control filter. The
control filter filters the air after the main filter to ensure
that no material continues to the suction source in
case of a main filter breakage. The control filter func-
tions as a safety device and does not increase the
filtration efficiency.
The pressure drop over the control filter is monitored,
and a signal is sent the control unit if above set value .
Pressure difference is preset at 4 kPa /40 mbar / 0.58
PSI . The pressure switch is located in the control box
(see picture no . 17 / 2) .
FlexFilter EX
The different components of the control filter (see
picture no . 6) are:
1 . Inlet
2 . Outlet
3 . Housing
4 . Vacuum measuring point (+)
5 . Vacuum measuring point (-)
6 . Ground cable
7 . Lid retainers (x4)
8 . Frame bracket
9 . Filter cartridge

Explosion protection

The CE and ATEX marking on the FlexFilter EX ensure
both a high level of safety and protection against
ignition of possible explosive atmospheres. However,
if an explosion occurs due to misuse, insufficient
maintenance or faulty installation, the FlexFilter EX is
equipped with additional protection methods to avoid
dangerous pressure build up in the filter.
The FlexFilter EX comes equipped with either an
Explosion Relief Panel, or an Explosion Suppression
System .
The Suppression System is normally only used if
venting is impossible due to the placement of the filter,
dangerous material properties or resulting flame and
pressure risk area .

Method 1: Explosion relief venting

The harmful effects of an explosion are minimised by
venting the pressure and flame of the explosion via a
relief panel. In case of an explosion, the resulting flame
and pressure escapes out the relief panel which must
be directed to a safe, unmanned area. This area will be
referred to as the "risk area"
The risk area must be clearly marked, for example with
a fence, warning lines and signs, and is to be off limits
during the time the filter is in operation. The area shall
be free of any flammable or combustible material or
other things in danger of being damaged by the flames
and explosion pressure .
EN
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