Honeywell UDA2182 manual 15.13Appendix L Leak Detection in PPB Applications

Appendices

15.13Appendix L – Leak Detection in PPB Applications

Before performing air leak detection, it is necessary to determine that both the probe and analyzer are working properly. Refer to Probe and Analyzers tests in Section 15.9

1.First, check to see that the probe contains an O-ring. Per the probe directions, an O- ring must go into a probe that is used in ppb applications. This creates a tight seal between the probe and flow chamber. MAKE SURE THIS O-RING IS IN THE PROBE.

2.Unless already in air, open the probe to air for 30 seconds.

3.Put it back into the process again.

4.Allow the DO to drift down to the 20-30 ppb range. The 20-30 ppb range was chosen because the reading was low enough that the drift was small with respect to the changes observed for various flow rates but high enough that changes could be observed.

5.At this range, vary the flow rate from 10 to 100 ml/min. These low flow rates were selected for two reasons. The first, the tester may only have a 0 - 100 ml/min flow indicator. The other reason is a leak that exists at this low flow, will cause a change in the DO reading.

6.If the DO value at 10 ml/min exceeds the DO value at 100 ml/min, a leak is present in the sampling line.

7.Fixing the leak may require plastic tubing to be replaced with metal tubing, tape to be put on fittings, and/or fittings at the bottom of the probe to be tightened securely.

8.Now, repeat Steps 2 - 6 until the flow can be changed from >100 ml/min to 10 ml/min with no change in the DO value.

226 UDA2182 Universal Dual Analyzer Product Manual January 2009