Permeation Tube ( Used With Izs Option ) - Teledyne 6400A Instruction Manual

TAI Model 6400A SO
6.5 Permeation Tube (used with IZS option)
SO is normally a gas at room temperature and pressure, but can be liquefied at moderate
2
pressures. The permeation tube consists of a small container of SO
of PTFE which is permeable to SO
the nanogram/min range. If the tube is kept at constant temperature, usually about 50
device will provide a stable source of SO
intended to be used as a periodic span check and is not to be used as a calibration device.
See below for permeation tube ordering information.
The permeation tube SO
o
1 slpm @ 50 C), the permeation tube temperature (
output is a fixed function of the permeation tube and is noted on shipping container.
The temperature is set at 50.0
to verify that the temperature is properly set. It should be set to 50
temperature warnings set at 49
tube at all times to prevent build-up of SO
If desired, the output of the permeation tube can be adjusted by adjusting the oven temperature up or
down slightly. The adjust increment is 0.1
temperature.
When the IZS system is in SPAN mode, the flow across the permeation tube is the sum of the
reaction cell flow and the purge flow, which is about 700 cc/min. The gas concentration can be
calculated using following equation;
PxKm
C =
F
where
P=permeation rate, ng/min.@ 50
Km=(24.46)/molecular weight, where 24.46 is the molar volume in liters @ 25
760mmHg
F=total flow rate (sum of sample flow and purge flow), cc/min.
C=concentration, ppm.
Analyzer Operator Manual, 02164, Rev. G
2
. The gas slowly permeates through the window at a rate in
2
2
concentration is determined by the permeation tube specific output (ppb @
2
o
C. Check SETUP-MORE-VARS and scroll to the IZS_SET variable
o o
C and 51 C. There is a 50 cc/min purge flow across the permeation
2
o
C to facilitate small adjustments of the setpoint
o
C.
Km for SO =0.382, H2S=0.719.
2
gas for a year or more. The IZS permeation tube is
o
C) and the air flow across it (slpm). The specific
o
gas in the tubing.
6-6
liquid, with a small window
2
o
C, the
C with over-and-under
o
C,