Micromeritics Gemini VII 2390a, Operator'S Manual

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Gemini VII Preventive Maintenance
239-42828-01 - Dec 2012 9-5
Lubricating Elevator Drive Assembly
The elevator screw is lubricated before it leaves the factory and should not require lubricating. If the
elevator starts to vibrate or becomes noisy when traveling, contact a Micromeritics Service Represen-
tative for disposition.
Cleaning the Analyzer
The exterior casing of the analyzer may be cleaned using a clean cloth, dampened with isopropyl alco-
hol (IPA), a mild detergent, or a 3% hydrogen peroxide solution.
Do not use any type of abrasive
cleaner
.
Cleaning the Analysis Dewar
Ice and suspended frost particles may accumulate in the bottom of an analysis port Dewar. Particles or
deposits exceeding 1/4-in. (0.64-cm) in depth may jam between the bottom of the sample tubes and the
bottom of the Dewar, causing the Dewar not to raise fully. Accumulations of fine particles impede liq-
uid nitrogen circulation around the bottom of the sample tubes. This causes the sample temperature to
be slightly higher which, in turn, can cause pore volume measurement errors in those samples exhibit-
ing high isotherm slope above 0.97 relative pressure.
Accumulated ice is likely to melt and form a pool of water in the Dewar if all liquid nitrogen evapo-
rates. The water must be removed, otherwise it will solidify when liquid nitrogen is added and could
press on the bottom of the sample tube causing breakage.
To ensure problems do not develop due to ice accumulation, check the Dewar after each use. Clean the
Dewar on a weekly basis.
1. Remove the sample tubes from the analysis ports.
2. Go to
Unit [n] > Show Instrument Schematic
to display the instrument schematic, then go to
Unit [n] > Enable Manual Control
.
3. Right-click on the elevator icon and select
Lower
to lower the elevator to its lowest position.
4. Remove the Dewar and pour the liquid nitrogen from the Dewar into an appropriate cryogenic
container.
Do not allow liquid to penetrate the casing of the analyzer. Doing so could result in
damage to the unit.
When handling Dewars, be sure to observe the Dewar precautions outlined in

chapter 3.
Do not pour liquid nitrogen directly into a sink. Doing so may cause drain pipes to
burst.