Chapter 5: Using Your Glove Box
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•
Perform purge and fill cycle on the transfer chamber using the
vacuum outlet and gas inlet valves. Depending on the vacuum level
achieved, it takes 1-5 cycles to reduce oxygen and moisture levels
below 1%. Porous materials being transferred may require longer
sustained vacuum purges to remove the oxygen and moisture trapped
in the materials.
•
After transferring materials to the main glove box chamber, perform
the required purge and fill cycles on the main chamber using the
vacuum outlet and gas inlet valves. To automate the purge and fill
cycles (1-199) for both glove box chambers, the addition of the
Automatic Pressure Controller (5238600 or 5238601) is
recommended (see Chapter 7). Normally 75-100 purge and fill cycles
will reduce moisture and oxygen levels below 1% (see Appendix D).
An additional 30-50 cycles will reduce moisture and oxygen levels
below 0.3% or 3,000 ppm.
The use of external glove port caps will
expedite the purge and fill cycle times and help maintain low
moisture and oxygen levels when the glove box is not in use.
•
Maintaining a slight main chamber positive pressure can help to
preserve the glove box atmosphere. The moisture/oxygen permeation
rates are reduced at slightly positive pressures (see Appendix E).
•
Recirculating drying trains are
required
to further reduce and
maintain oxygen and moisture levels below 1%.
Labconco oxygen
and moisture removal drying trains can maintain oxygen levels
below 5 ppm and moisture levels below 50 ppm.
•
Monitoring moisture and oxygen levels inside the glove box is
recommended
by using accessory monitors (see Chapter 7).
Work Techniques
•
Segregate all clean and contaminated materials in the work area.
•
Maintain work at a slightly negative pressure if working with
hazardous compounds.
•
Continuously run the recirculating oxygen and/or moisture drying
train to
preserve
the inert atmosphere if so desired.
Transferring Materials to the Outside
•
All open chemical weigh vessels or containers
must
be sealed before
removing materials from the glove box main chamber.
•
Upon completion of work, the main glove box chamber
must
be
purged and filled approximately 5-10 times to remove airborne
contaminants from the work area. The exact number of cycles should
be determined by your Safety Officer.
