Leak Testing - Teledyne 3110 Operating Instructions Manual

Maintenance

4.8 Leak Testing

WARNING: IF A LEAK IS SUSPECTED IN THE UNIT, DO NOT
ATTEMPT TO TIGHTEN THE QUICK DISCONNECT
FITTINGS. THE FITTINGS ARE POTTED IN EPOXY
AND TIGHTENING THEM WILL BREAK THE SEAL.
To check for leaks, TAI recommends one of the following
procedures:
Procedure I:
1. Purge the instrument to as low a value as possible. Use a
sensitive range for analysis for instance, 0-1% range. Take
note of the oxygen concentration.
2. Place the vent line in water and disconnect the sample.
3. Next, disconnect the vent line and use the same analysis
range. The reading should not increase above the level to
which you purged to.
Procedure II:
1. Purge the instrument with nitrogen at the sample port.
2. Using a flow rate of approximately 1 SCFH, note the reading
once it has stabilized (at least 24 hours on the 0-10 PPM
range).
3. Increase the flow rate from 1 SCFH to 2 SCFH.
4. Note how much the reading has changed after a few minutes.
5. Reduce the flow rate to 0.5 SCFH.
6. Note how much the reading has changed.
7. The reading should change by less than 10% of the original
value.
Teledyne Analytical Instruments
46
Model 3110