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ATEX Instruction Manual
HAS8xE-IM-ATEX
January 2004
1-1
Application and Principle of Operation
The gas analyzers of type BINOS
and MLT 2 are intended to measure gas
components within gas mixtures. In
combination with an approbriate certified
purge system (protection method
„Pressurized Enclosure" EEx p) they can be
installed and operated in hazardous areas
of Zone 2.
Pressurization acts as external explosion
protection and prevents external explosive
atmosphere to penetrate into the analyzer
by holding the enclosure at an overpressure
compared to the surrounding
The type of purge system used varies
dependent on the area where the analyzer
is intended to be installed. Both systems
offer two modes of operation:
EEx p with continuous flow
•
and
•
EEx p with leakage compensation.
Dependent on the sample gas composition
it may be necessary to take care of internal
explosion protection which refers to the
sample gas path (containment system) in
the analyzer.
One of the following protection methods is
used:
•
Nonflammable gases and gas
mixtures below the LEL: It must be
ensured that the sample gas in the
containment system always remains
below the lower explosive limit!
Emerson Process Management Manufacturing GmbH & Co. OHG
SECTION 1
Technical Description
100 F
•
•
•
MLT 2 / BINOS
Flammable gases and gas mixtures
may be analyzed when the sample gas
is diluted below ¼ LEL outside the
analyzer, so the resulting sample gas
is to be categorized „nonflammable".
The diluting system must ensure that the
gas in the containment system always
remains below ¼ LEL.
Flammable gases and gas mixtures
may be analyzed when the analyzer
enclosure has an internal overpressure
of > 50 Pa over the pressure in the
containment system. To ensure this
condition a differential pressure switch
is used and connected between
containment system and analyzer
enclosure. In case the pressure
decreases below the level of 50 Pa the
switch is activated and may be used to
activate an alarm or analyzer shut-off.
If more than one switch is needed
because more than one flammable gas
is supplied to the analyzer, the contacts
of these switches have to be connected
in series. Purge medium may be inert
gas or air. Flame arrestors are required
for all gas inlets and outlets carrying
flammable gases.
Explosive gases must not be
connected to the analyzer!
100 F
1 - 1
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