Purge The Sensor Case - Emerson Micro Motion TA Series Installation Manual

Pressure relief
5.1

Purge the sensor case

Whenever a purge plug is removed from the sensor case, you must repurge the case.
Prerequisites
Make sure the following are available before beginning the purge procedure:
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Procedure
1.
2.
3.
4.
5.
10
™
Teflon tape
Argon or nitrogen gas sufficient to purge the sensor case
Shut down the process, or set control devices for manual operation. Before
performing the case purging procedure, shut down the process or set the control
devices for manual operation. Performing the purge procedure while the flowmeter
is operating could affect measurement accuracy, resulting in inaccurate flow signals.
Remove both purge plugs from the sensor case. If purge lines are being used, open
the valve in the purge lines.
DANGER!
• Stay clear of the rupture disk pressure relief area. High-pressure fluid escaping from
the sensor can cause severe injury or death. The sensor must be oriented so that
personnel and equipment will not be exposed to any discharge along the pressure
relief path.
• Take all necessary precautions when removing purge plugs. Removing a purge plug
compromises the secondary containment of the sensor and could expose the user to
process fluid.
• Improper pressurization of the sensor case could result in personal injury.
CAUTION!
Be sure to use thread protectors when removing the purge fitting so as not to damage
the disk membrane surrounding the rupture disk.
Prepare the purge plugs for reinstallation by wrapping them with 2–3 turns of Teflon
tape.
Connect the supply of nitrogen or argon gas to the inlet purge connection or open
inlet purge line. Leave the outlet connection open.
• Exercise caution to avoid introducing dirt, moisture, rust, or other contaminants
into the sensor case.
• If the purge gas is heavier than air (such as argon), locate the inlet lower than the
outlet, so that the purge gas will displace air from bottom to top.
• If the purge gas is lighter than air (such as nitrogen), locate the inlet higher than
the outlet, so that the purge gas will displace air from top to bottom.
Make sure that there is a tight seal between the inlet connection and sensor case, so
that air cannot be drawn by suction into the case or purge line during the purging
process.
Micro Motion TA Series