Agilent Technologies 8255 Nitrogen, User Manual, Page: 40 / 118

40 SCD and NCD User Manual
3
System Description
Figure 6 SCD flows
For the NCD, the burner provides two heated zones, one at the
base and one farther up the assembly. In the burner base region,
the column effluent mixes with hydrogen and air at high
temperature. The resulting hydrogen flame combusts the
effluent. Low concentration components will burn to form the
usual combustion products, including NO
2
for compounds
containing nitrogen. The products are drawn upward through a
quartz tube and catalyst, where a high temperature will convert
NO
2
into NO.
Figure 7 shows the flow paths for the NCD burner assembly.
Upper hydrogen
Lower hydrogen
Oxidizer
Column
&ROXPQÁRZ
To detector
Base heater
Burner
Ceramic tube,
lower
Ceramic tube,
upper