Micromeritics FlowSorb III 2305 Operator's Manual page 46

Performing a Single-Point Surface Area Measurement
8. FlowSorb 2310: Press the Reset button to lower the Dewar tray to its low-
est postion
FlowSorb 2305: Press the release tab to the right of the Dewar tray to allow
the tray to hang down.
9. Fill a 1-mL precision syringe to 1 mL with nitrogen gas:
a. Hold the needle tip immediately above the level of liquid nitrogen in the
b. Flush the syringe a few times to ensure a proper fill; wipe the needle tip
c. Lay the syringe aside (perhaps on the rubber mat of the FlowSorb) so
10. While the syringe is equilibrating, use the FLOW knob to regulate the nitro-
gen-helium flow through the instrument so that the flowmeter float is cen-
tered on the marked line.
11. Use the Coarse and Fine Zero knobs to zero the instrument. Observe the
display for a few minutes to establish system stability. A change of no more
than 0.01 should be achieved.
The two primary factors leading to excessive instability are:
•
instrument warm-up, which may require up to 30 minutes after initial
power application, and
•
the progression of residue from a previous analysis, which can require as
much as 10 minutes for elimination.
Be sure these situations do not exist when setting the zero. Once set, the
zero should not be readjusted unless a sustained change beyond ± 0.02 units
occurs.
12. Depress the Surface Area and the Clear SA Display pushbuttons.
13. Hold the syringe at the rear flange so that body heat does not affect the gas
volume contained by the syringe barrel.
14. Insert the needle fully into the Inject septum.
3-6
cold trap Dewar. The evaporating liquid provides an atmosphere of pure
nitrogen.
free of accumulated frost.
that the gas can equilibrate to room temperature.
FlowSorb III
Mar 2012