Teledyne OT-2 - Oxygen transmitter system - Manual (Page 27)

Model OT-2 System Operation 3
3-9 Teledyne Analytical Instruments
3.3.3 H
2
S Scrubber
The life expectancy of the stainless steel H
2
S scrubber, in-
cluded in this system, is determined by the amount of H
2
S passing
through it.
With the maximum concentration of 200 PPM H
2
S and a flow
rate of 0.2 scfh the expected scrubber life will be over 6 months
with Purifil
® and over 11 months with Purifil ® II.
This scrubber life expectancy increases with lower H2S con-
centration or gas sample flow rates. It is recommended that the
flow rate be set no higher than 0.4 scfh initially. The flow rate
should be increased only if a faster system response time is de-
sired.
It is suggested that a spare scrubber be kept on hand and
replaced every 6 months. When the scrubber needs to be re-
placed, follow the procedure in section 4,
Maintenance, "Scrub-
ber Replacement".
WARNING: IF SCRUBBER IS NOT PROPERLY MAINTAINED THE
O
2
SENSOR LIFE WILL BE SHORTENED.
3.3.4 Exhaust/Vent Line (Sample Return)
It is recommended that a long vent line (approx. 4 ft.) be
installed to the "Sample Return" connector at the side of the sys-
tem enclosure. The extended vent line will minimize back diffusion
from the atmosphere back to the sensor. The minimum recom-
mended tubing diameter is 1/4" to minimize back pressure.
3.4 Testing the System
Before connecting the instrument into the power source:
• Check the integrity and accuracy of the gas
connections. Make sure there are no leaks.
• Check the integrity and accuracy of the electrical
connections. Make sure there are no exposed
conductors.
• Check that inlet sample pressure is within the
acceptable range (see section 3.3.1).
• Power up the system, and test it.