Gow-Mac 400 Series, Operating Manual

Page: 21 / 64

21 Series 400 / 402 Gas Chromatograph Operating Manual GOW-MAC Instrument Co.
May 2017, Rev. 7
3.11 Gas Flow Adjustments
!
IMPORTANT
Inert carrier gas MUST be fl owing through both columns A and B as well
as sides A & B of the TC detector. THIS IS EXTREMELY IMPORTANT and
NECESSARY to preserve the fi laments!
Failure to set fl ow rates on both sides causes oxidation and destruction of the
fi laments in the presence of oxygen.
A bubble type fl owmeter attached to a stand should be connected to OUTLET PORT "A" by
means of a fl exible tube (Figure 3-4). Fill the reservoir of the meter with a 2 - 3% liquid soap
or detergent solution. A stopwatch is recommended for the fl ow measurement. Proceed as
follows:
A. Gently squeeze the reservoir of the fl owmeter until a stream of soap bubbles emerge.
Allow the soap bubbles to rise and wet the sides of the glass meter.
START
the stop
watch when a soap bubble reaches the "0" mark on the meter.
STOP
the stopwatch
when the soap bubble reaches the "10" mark on the meter. The elapsed time, in seconds,
for the soap bubble to rise from "0" to "10" mL divided into 600 equals the fl ow rate in
mL/min. Adjust
SIDE "A" FLOW CONTROL VALVE for the desired fl ow rate
(about 60 mL/min.).
600 = fl ow rate
sec
NOTE
&
Before each measurement, allow one minute or so for the
fl ow rate to equilibrate after each adjustment.
B. Change the flowmeter to SIDE "B" OUTLET PORT and adjust column "B" for the
same fl ow rate (about 60 mL/min)
C. The fl ow rates have now been adjusted. Disconnect the fl owmeter.