Labconco XPert Weigh Boxes 5220331 - Manual (Page 19)

Chapter 3: Getting Started
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• Glove box fluorescent lamp light levels “illumination” (measured across
the work surface) averaged 29.9 foot candles with room lights turned off
and 33.7 foot candles with the test lab’s overhead fluorescent lights
turned on.
• Static pressure measured inside the glove box varied from negative 0.14
inch of water column at minimum 13-CFM to negative 0.91 inch of water
at maximum 100-CFM. The total system static pressure measured
between the exhaust filter and the blower varied from negative 0.34 inch
of water column at 13-CFM to negative 2.4 inches of water at 100-CFM.
• The vibration level “displacement” measured on the work surface is
negligible at minimum through maximum airflow volume settings. The
measured level of displacement ranged from 0.59 x 10
-5 inches to 1.45 x
10 -5 inches.
• The static electricity measured on the work surface and interior surfaces
of the glove box achieved a negligible level (below +/- 100V on any
surface) with the glove box blower operating at a min 13-CFM to max
100-CFM at 22% relative humidity. Test conditions included the ionizer
fan speed set to high output and the potentiometer within the ionizer was
adjusted slightly between positive and negative output in order to
maintain balanced ionization. The time required for sufficient
electrostatic decay will vary depending upon user application, moisture
levels within the supply air and the level of cleanliness within the glove
box interior. Anti-Static Ionizer Fan is sold separately (see Chapter 7).
• The helium leaks ranged from 2 x 10 -4 to 1 x 10 -6 ml/sec with no
individual leak greater than the specified 1 x 10 -3 ml/sec.
• Balance stability testing results were excellent with no detectable
instability of an analytical balance to five decimal places and a top loader
balance to three decimal places. Test results were confirmed for various
sample weights with the glove box running at various blower airflow
settings.