Micromeritics GEMINI VII KEYPAD, Руководство оператора

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2 Operational Procedures
D
ETERMINE THE
S
AMPLE
M
ASS
Sample Data Worksheet for Gas Adsorption on page E - 1
Analyze Samples with a Total Surface Area of 1.0 m2 or Less on page D - 1
The equipment images in this topic may differ slightly from your equipment; however,
the instructions are the same unless otherwise noted.
There are several different surface area ranges that require different protocol for optimal results.
n
If there is between 0.1 m
2
and 1 m
2
in the tube, follow the recommendations for balancing the
free space using glass beads, along with filler rods, and measure the resulting free space
difference.
n
If there is between 1 m
2
and 5 m
2
of total surface under test, measure the free space difference
between the two tubes as a part of each analysis.
n
If there is between 5 m
2
and 30 m
2
, use the option to calculate the free space difference
between the two tubes using the density of the sample in the tube, along with the mass entered.
There are some special considerations when using the tubes with the cylindrical bulb on the
end as opposed to the straight-walled tubes.
n
If there is more than 30 m
2
in the tube total, it may not be necessary to determine the free
space difference between the two tubes as a part of the analysis.
Smaller quantities are required for samples having high surface areas. These samples require
careful weighing after degassing because a small error may represent a considerable percent of
total mass. Proper weighing techniques are most important in this case. Use no less than 100 mg
to reduce the effect of weighing errors.
Care should be taken when loading powders: the accessory funnel is useful for this purpose.
Large granules or chunks may be loaded with forceps.
Analysis results are expressed in units of surface area per gram of sample; therefore, it is
important to know the true sample mass.
Follow the instructions on the Sample Data Worksheet and complete all fields to find the true
sample mass.
1. Record the sample tube identification on the Sample Data Worksheet.
2. Place the sample weighing support on the balance. Tare the balance and allow it to stabilize
at zero (0).
3. Place the empty sample tube set (empty sample tube and stopper) on the sample weighing
support and place it on the balance.
4. Record the stabilized mass on the Sample Data Worksheet . Remove the sample tube set
from the balance.
2 - 8
Gemini VII Keypad Operator Manual
239-42801-01 (Rev E) — July 2021