Teledyne 402REU - Hydrocarbon analyzer - Manual (Page 33)

Total Hydrocarbon Analyzer Operations
4-9 Teledyne Analytical Instruments
Set the process sample regulator to 30 psig.
Switch the gas selector switch to SAMPLE and set range switch to a
range which comfortably accommodates the process fluctuations in sample
hydrocarbon concentration. Sample flow should now be established.
NOTE: On standard instruments, the hydrocarbon concentration of a
mixture of different species of hydrocarbons will be indicated as if it
were only methane, unless the instrument is specifically calibrated
to read a different species.
4.10 Routine Operation
The pressure gauges and bypass flow rate should be checked on a
daily basis to insure continuous flow. The large cross-sectional area of the
sintered disc restrictors should eliminate the possibility of particulate
matter stopping or restricting flow. Nevertheless, even with the design
safeguards, the condition of the system should be checked daily. Any
change in fuel or sample flow rate will result in a change in signal output.
Since the only moving parts in the system are the fuel shut-off sole-
noid valve and the flame guard relay, no routine maintenance is required to
keep the electrical portion of the analyzer operative. The relay is designed
to operate continuously in an energized condition. In the event of failure,
the relay is a plug-in device.
4.10.1 Verification of Calibration
Repeat the zero and span standardization until no further adjustment
of either control is necessary to produce repeatable readings when switch-
ing from zero to span conditions.
Whenever a change is made in the pressure settings of either the air, fuel,
or sample regulators of the instrument, the instrument must be recalibrated. the instrument must be recalibrated. the instrument must be recalibrated. the instrument must be recalibrated. the instrument must be recalibrated.
IMPORTANT: The accuracy of the analysis can be no better than the
user’s knowledge of the hydrocarbon content of the stan-
dardization gases.
These gases should be procured from a supplier who will certify their
composition. If a wide discrepancy exists between the span setting re-
corded in the manual and that finally reached through the use of span gas,
you should investigate either the zero or span gas composition, or both. If