Teledyne 402REU - Hydrocarbon analyzer - Manual (Page 9)

1-3 Teledyne Analytical Instruments
Total Hydrocarbon Analyzer Introduction
onstrated when zero and span gas are exchanged during the standardization
procedure.
The restrictors used in the system look alike; however, they are not
interchangeable.
1.3.3 Fuel and Blanket Air Systems
The fuel and blanket air systems use similar components. Stable flow
is achieved by maintaining a constant pressure across restrictors upstream
from the cell. Each system incorporates an adjustable pressure regulator,
pressure gauge, and restrictor. A flame out light is included to indicate
when the flame fails. A fuel shut-off solenoid valve, mounted on the line
that supplies hydrogen, stops the fuel flow in case of flame failure. This
valve is located in line with the fuel port; except for instruments using
hydrogen as the sample gas. In this case, the sample is used as fuel and the
valve is located in line with the sample port. See Figure 1-1A for a flow
schematic for instruments equipped with a sample selector module. Figure
1-1B shows the flow schematic for instruments without the optional gas
selector module.
1.3.4 Flame Ionization Detection Cell
The sample and fuel are combined within a tee fitting located in the
isothermal chamber. The mixed gas is emitted from a burner within the
sensor assembly. Blanket air is introduced into the sensor (or cell) by
means of a separate fitting that is located in the base section of the assem-
bly. The upper half of the assembly houses the anode-igniter, collector, and
flame guard thermistor. The cell is located at the left hand front area inside
the enclosure for easy access. See Figure 1-2.
1.4 Applications
• Monitoring the purity of oxygen, argon, nitrogen and other
gases in the manufacture of microcircuits.
• Monitoring hydrocarbon contamination in air liquefaction and
other gas production processes.
• Gas purity certification.
• Detecting trace hydrocarbons in ambient air.
• Detecting atmospheric pollutants.
• Cryogenics.
• Monitoring for fuel leakage or toxic solvents.
• Monitoring hydrocarbons in a wide range of process streams.