Differential Pressure Switch; Preparation - Emerson ROSEMOUNT MLT 2 Upgrade Manual

MLT 2 / BINOS
4.2.5

Differential Pressure Switch

If a differential pressure switch is installed
(analyzer designed to measure flammable
gases), it must be tested for proper operation
on a regular basis, at least once a year.
Do not operate the instrument measuring flammable gases with a differential
pressure switch not properly configured!
Violation may result in explosion, fire, and/or electrical hazards!

4.2.5.1 Preparation

Required tools:
•
Manometer with full scale up to 50 and a
resolution of 0,1 mbar.
•
Flow meter with full scale up to 5 l/min,
resolution 0,1 l/min.
To carry out the tests, perform the following
steps (see fig. 4-2):
• Install the analyzer and attached pressu-
rization system as for operation.
• Instead of connecting the sample gas
line, connect the test gas supply to the
gas inlet. If an optional flame arrestor is
installed, disconnect it and use the inlet
fitting at the analyzer enclosure! Ensure
4-4

100 F
4.2
EXPLOSION HAZARD
Routine Tests
Also perform the test described below
after having modified or repaired contain-
ment system components!
Proper operation means, the switch is activa-
ted when the pressure inside the containment
exceeds the pressure inside the analyzer enc-
losure (14 mbar), thus activating the control
unit to shut-down the analyzer.
•
Test gas: Air or Nitrogen
•
Pressure regulator to reduce the test gas
pressure to max. 25 mbar.
the pressure regulator and the manome-
ter are installed in front of the gas inlet
and setup to reduce the pressure to max.
10 mbar. Do not apply gas yet.
• Disconnect the sample gas outlet from
your process lines to release the test gas
into the ambient.
• Connect the analyzer and the pressuri-
zation unit to power. Open the purge gas
supply to start prepurging the analyzer.
Emerson Process Management GmbH & Co. OHG
ATEX Instruction Manual
ETC01035
02/2008