Teledyne TEXIO PTE6-200 Operating Instructions Manual page 134

Percent Oxygen Analyzer
CAUTION: FLOW RESTRICTORS HAVE VERY SMALL ORIFICES
AND MAY BE PLUGGED BY SMALL PARTICLES
(.005" DIA OR LARGER) A SAMPLE FILTER MUST
BE INCLUDED IN THE SAMPLE LINE PRIOR TO THE
RESTRICTOR! A 50 MICRON FILTER IS
RECOMMENDED.
3000RS-P EXAMPLES:
Example 1: With an incoming pressure of 10 psig the standard restrictor
(blue dot) will provide a flow rate of .76 SLPM. Upstream of the
restrictor the sample line pressure will be 10 psig, while downstream
(including the cell) the pressure will be at atmospheric pressure
(analyzer vented to atmospheric pressure). Note, all other pressure drops
in the sample path are insignificant at these flowrates. This ensures that
the cell operates at atmospheric pressure. At very high flow rates (off
scale of flowmeter), pressure drops other than the restriction device
could become significant, and result in pressurizing the cell.
Example 2: A 3000RS-P is configured for vacuum service as follows.
The un-marked restrictor is placed in the sample vent port. The
downstream end of the restrictor is then connected to a vacuum pump
and bypass valve. The bypass valve is adjusted to provide a flow rate of
1 SLPM. The sample pressure between the pump and the restrictor will
be approximately -7 inches of mercury, while the pressure in the balance
of the sample system including the cell will be approximately at
atmospheric pressure. (Provided the sample flow into the analyzer is not
blocked.)
BYPASS:
To improve the system response, a bypass can be added to increase
the sample flow rate to the analyzer by a factor of ten. A bypass
provides a sample flow path around the analyzer of 2-18 scfh, typically.
CALIBRATION GAS:
For 3000 series analyzers with the Auto-Cal option, the customer
must supply control valves (or restrictors) for any SPAN or ZERO gas
source which is attached to the Auto-Cal ports. The valve should be
adjusted to the same flow rate as the sample gas. When restrictors are
used, the gas pressure must be adjusted to achieve the proper flow rate.
Teledyne Analytical Instruments
Appendix
119