User's Manual

Page 20 SITRANS LR560 (mA/HART) – INSTRUCTION MANUAL 7ML19985KB01
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Installation
Air Purging System
For convenient cleaning, a purging inlet is provided above the antenna. The system
provides an 1/8" inlet (female thread) above the antenna where clean, dry air passes to
the face of the antenna lens to clean it. The customer will supply the purging air by a
manual or automatic valve system.
Purge Connection
• The purge connection is closed
by the manufacturer, using a 1/8"
plug.
• When the plug is removed to
connect a purging system, the
operator is responsible for
ensuring that the purging circuit
conforms to "Ex" requirements:
for example, by fitting an NRV
valve.
1)
Purge airflow
• The purge airflow is designed to create a strong vortex of air that rapidly cleans the
face of the lens.
• The air purge system can clean both dust and moisture off the lens.
Notes:
• Purge duration, pressure, and interval, will vary with each application. It is the user’s
responsibility to determine the requirements depending on the application and
cleaning required.
• Short duration bursts of high pressure provide more effective cleaning than continu-
ous low pressure air.
• It is the customer’s responsibility to ensure that any vacuum or pressure in the mea-
sured vessel is maintained, considering the hole that passes through the process
connection and SITRANS LR560 antenna system.
Air Consumption (Flow rate versus applied pressure)
Air Pressure (psi) Approx. inlet volume flow rate (SCFM)
20 5
40 10
50 15
80 20
100 25
110 30
Recommended 90 to 110 psi for effective cleaning
1)
1)
Air pressure in vessel can affect purge operation.
purge process
connection with
factory-installed
1/8" NPT plug