Leak Tests; Clean Air Leak Test - Thermo Scientific SOLA II Flare User Manual

Leak Tests

Clean Air Leak Test

Thermo Scientific
A leak test should be completed when starting up a new unit or replacing
components such as valves, rotors, regulators, gauges, etc., in the flow paths of
the clean air flow, nitrogen flow and sample flow. These three flow paths are
critical and must not leak. The clean air and nitrogen used should be zero-grade
and sulfur-free, as they are used in the sulfur analysis flow paths. Instrument air
is used for the oven air, electronics purge and valve actuation. Small leaks in the
instrument air flow are not critical, but check to ensure fittings are tight.
Caution Purge all sample lines with nitrogen until the total sulfur reading
stabilizes near zero ppm on the low range. Once the reading stabilizes, wait at
least 15 minutes to ensure all sulfur is purged from the system. Disconnect the
communication lines to prevent remote actuation of gas selection valves. Only
clean air and nitrogen are needed for the leak check. ▲
Once the system has been purged with nitrogen, lower the oven air pressure
below 4 psig to allow the oven and pyrolyzer to cool. After the oven cools, turn
the oven air pressure regulator off. All regulators for clean air, nitrogen and
sample should be set to zero psig. Leave the power on, as it will be needed
during the leak test to actuate valves.
1. Clean air 1, 2 and 3 flow paths are common to each other (teed
together) downstream of the injection valves and before the mixing
chamber, as shown in the flow diagram,
the clean air flow path for tightness.
2. Ensure the three clean air regulators are set to zero psig.
3. Cap the tube exiting the pyrolyzer into the pneumatics at the 1/8-inch
union. Remove the 1/8-inch Teflon tube and cap the union. This 1/8-
inch Teflon tube goes into the inlet of the PUVF detector. Without
applying pressure to the PUVF detector, check the fittings for tightness.
4. After capping the union, turn the pressure on the clean air 1 regulator
to 15 psig. As all three clean air flow paths are common downstream, all
three air gauges will slowly pressure up to 15 psig. This will take several
minutes, as there are restrictors in the flow paths.
5. Once all three clean air gauges read 15 psig, back off the clean air 1
regulator. The pressure may fall a few psig at first, but should then hold
steady on all three gauges since these are non-relieving regulators and
the downstream tube has been capped.
Maintenance & Troubleshooting
Figure 1-2. Check all fittings in
SOLA II Flare User Manual
Chapter 8
8-2