Permeation Tube; Table 6-5: Example Ofa - Teledyne 200A Instruction Manual

Teledyne API Model 200A NO
Table 6-5: Example of AutoCal Setup
Step Action
1. Press SETUP-ACAL
2. Press PREV-NEXT
3. Press MODE
3. Press PREV-NEXT
4. Press ENTR
5. Press SET
6. Press PREV-NEXT
7. Press EDIT
8. Press ENTR
9. Press PREV-NEXT
10. Press EXIT

6.5 Permeation Tube

NO - nitrogen dioxide - is normally a gas at room temperature and pressure, but can be liquified
2
at moderate pressures. The permeation tube consists of a small container of NO
small window of PTFE which is permeable to NO
through the window at a rate in the nanogram/min range. If the tube is kept at constant
temperature, usually about 50° C, the device will provide a stable source of NO
more. See below for permeation tube ordering information.
The NO concentration is determined by the permeation tube specific output (ng/min @ 1 slpm
2
o
@ 50 C), the permeation tube temperature (
output in ng/min is a fixed function of the permeation tube and is noted on shipping container.
The ng/min units can be converted to ppb units by the following equation:
⎛
perm
⎜ ⎜
=
ppb NO
2
⎝
Where:
perm tube output (ng/min) = The perm tube output in nanograms
46 gr/mole NO
560 cc/min = The flow rate of zero air over the permeation tube
24,500cc/m ole = The volume of air (at 25 C and 1 atm pressure) that contains 1 mole of air
molecules
Analyzer Instruction Manual, 02246, Rev. F1
X
Comment
This button sequence will cause the AUTOCAL menu to be displayed
Press PREV-NEXT until SEQ 2 is displayed
Select the MODE menu
Press PREV NEXT to scroll to SPAN
ENTR selects the SPAN MODE
Select the SET menu to change the sequence attributes
Scroll the SET menu to TIMER ENABLE
Allows changing the TIMER ENABLE attribute, select ON
ENTR changes TIMER ENABLE to ON
Repeat steps 6-9 for each attribute
Press the EXIT key to return to upper level menus
tube output ( ng / min)
46 gr / mole NO
2
= The molecular weight of nitrogen dioxide (NO
2
, see Figure 6-1. The gas slowly permeates
2
o
C) and the air flow across it (slpm). The specific
⎞
⎛ ⎞
560 cc / min
⎟ ⎟
⎜ ⎟
⎝ ⎠
⎠
24 , 500 cc / mole
6-5
liquid, with a
2
gas for a year or
2
/mi nute
)
2