Teledyne 3300PB Operating Instructions Manual page 23

Percent Oxygen Analyzer
3.4.1 Vacuum Service Option
For vacuum service pluming reference figure 3-4. The vacuum service
option is recommended for applications in which the sample source is not
pressurized. The customer must supply a pump and bypass system to com-
plete the sample system. The sample inlet and outlet pressure must be
maintained at a constant pressure for proper performance. If the sample inlet
or vent pressure will not be held constant during the process, a pressure
regulator must be used to regulate the pressure across the cell.
Adjust the flow rate on a vacuum service system as follows:
Select Sample with the three-way control valve and open the flow
control valve on the analyzer to full flow (located on the analyzer flow
meter). Open the pump bypass valve, and turn on the pump. Readjust the
pump by-pass valve to limit the maximum flow rate to full scale on the
flowmeter with the flowmeter valve fully open. Adjust the analyzer flow
control valve (flowmeter valve) to a flow-rate of approximately 2 SCFH).
Select Span and verify that the span and Sample gas are at different pres-
sures. The calibration accuracy will be adversely affected if the Span and
Sample gases are at differing pressures.
If the span gas is provided from pressurized source, a control valve
must be added between the analyzer and the span gas source. This valve is
used to adjust the span flow rate to match the sample flow rate. Do not
adjust the span flow rate with the flow control valve located on the analyzer
for units with vacuum service options.
Figure 3-4: Piping Diagram for Vacuum Service Option
Teledyne Analytical Instruments
Installation 3
3-7