Bronkhorst EX-FLOW Mass Flow - Manual (Page 18)

BRONKHORST HIGH-TECH B.V.
3 OPERATION
3.1 General
The Bronkhorst High-Tech B.V. Mass Flow Meters/Controllers are designed in such a way that they will meet
user process requirements.
3.2 Power and warm-up
Before switching on power check if you have connected all the pins according to the hook-up diagram which
belongs to the flow meter/controller.
It is recommended to turn on power before applying pressure on the instrument and to switch off power after
removing pressure.
Check gas connections, and make sure there is no leakage. If needed, purge the system with a proper gas.
Turn on power and allow for at least 30 minutes to warm-up and stabilize. During warm-up period gas
pressure may either be on or off.
3.3 Start-up
Be sure your tubing is absolutely clean, free of dust, moisture etc., and your gas is cleaned by an adequate
filter. Turn on fluid supply gently. Avoid pressure shocks, and bring the instrument gradually up to the level of
the actual operating conditions. Also switch off fluid supply gently.
3.4 Operating conditions
Each instrument has been calibrated and adjusted for customer process conditions.
Controllers or valves may not operate correctly, if process conditions vary too much, because of the
restriction of the orifice in the valve.
For flow meters performance and accuracy may be affected tremendously if physical fluid properties such as
heat capacity and viscosity change due to changing process conditions.
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