GE MOA 280i, Operation And Maintenance Manual

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GE Analytical Instruments ©2006
8-5
DLM 14291 Rev. A
•
Connect the Inspiratory Filter to the filler body. The lifetime of the filter will
depend on the concentration of nitric oxide in the inspired air and the
frequency of use. A reasonable estimate is three months from the date it is
installed. Calculate three months from the day the filter is installed and write
that expiration date in the space provided on the filter. Screw the filter onto
the threaded end of the body. The Bag Kit is now ready for use.
Cleaning the Bags
Mylar bags should be cleaned prior to use and this same procedure can be used to
reuse the bags. The vacuum pump on the NOA or another vacuum source is used to
withdraw all of the gas from the bag and the bag is then filled with a dry gas
containing low levels of NO. Suitable gases include cylinder nitrogen, air or
oxygen. House air or oxygen can also be used if the NO level in these gases is < 5
ppb. The gas is again removed using the vacuum pump on the NOA. Usually a single
flush with low NO gas is sufficient to remove any NO absorbed on the bag’s walls,
although multiple flushes with low NO gas can also be performed. The flow rate on
the NOA 280i is limited to 200 mL/min by the frit restrictor. This means a full bag
(~12 L) will take about 60 minutes to empty. If the frit restrictor is removed and
the gas sampling package connected directly to the NOA inlet, the bags can be
evacuated in ~ 10 minutes. Alternately, another vacuum source such as house
vacuum or a vacuum pump can be used to evacuate the bags.
WARNING:
ALWAYS USE THE VACUUM PROCEDURE TO REMOVE GAS FROM THE BAG. DO
NOT ATTEMPT TO REMOVE GAS FROM THE BAGS BY HAND, AS SQUEEZING THE
BAGS MAY INTRODUCE PINHOLE LEAKS.
After evacuation, the bags will be under a slight vacuum and when disconnected
from the vacuum source, room air will be drawn into the bag. If ambient NO levels
are high, this can contaminate the bag. The best procedure is to use a 3-way
valve, with one leg connected to the zero air filter, one leg to the vacuum source