Non-Reproducible Calibrations - Micromeritics FlowSorb III 2305 Operator's Manual

FlowSorb III

Non-Reproducible Calibrations

A damaged and leaking septum should be eliminated as the first possible cause of
non-reproducible calibrations. Replace the septum with a new one if there is any
doubt as to its integrity. (Refer to Replacing the Septum in this chapter.)
The knurled nut which retains the septum should be finger-tightened. Insuffi-
cient or excessive tightening may cause system leakage.
Check the syringe for gas tightness and freedom from obstructions in the needle.
Immerse the needle tip under water and press the plunger; this should result in a
steady stream of bubbles with no resistance to motion from the plunger. When
performing this check, be careful not to draw water into the syringe. Allow the
needle to dry thoroughly before using for calibrations.
Monitor the flow rate by observing the flowmeter float to see that it is constant.
If it does not maintain a steady position, check the following:
• the gas regulator setting for its recommended 15 psig setting
• the flow control knob for smooth operation
• gas leaks about the septum, the sample tubes and holders, the gas inlet
connection, and internal plumbing connections.
Also refer to Detector Drift in this chapter.
Aug 00
Troubleshooting
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