SERVO
PRO NANOCHROME Gas
Analyser
108
04416001A / Revision 7
Trap In & Trap Out
The oven
Inlet
gas connector is taken to the analyser chassis
Trap In
gas
connector.
The oven
Outlet
gas connector is taken to the analyser chassis
Trap Out g
as
connector.
VCR tubing should be used in all cases.
6.3.4 Internal dilution system setup
The internal dilution system uses carrier gas to dilute a calibration gas to a fixed
ratio, nominally a factor of 20 to generate a suitable span gas concentration. That
means a suitable span gas concentration of 5ppm will be diluted to 250ppb.
Figure 54 : Internal dilution system schematic
The dilution ratio is a function of the carrier gas inlet pressure and span gas inlet
pressure connected to sample inlet 2. The internal restrictors are set during
production but it is important to re-calculate the dilution ratio during installation
or every time the supply pressures are changed.