UEi Test Instruments KM9106/P - Manual (Page 45)

KM9106 Operators Manual 45
10. Main Purge
The main purge facility for Quintox is used where longer sampling of flue gas is
required. It should be used with the KM9008 gas conditioning unit or in conjunction
with any other water removal system.
If dry gas is supplied to the Quintox for a long period of time the operating cells will
dry out and stop working. Supplying fresh ambient air to the sensors on a periodic
basis will prevent or reduce the drying effect and prolong sensor life. Ideally the fresh
air should be at 50% relative humidity but it is understood under certain conditions
this may not be possible.
Main purge introduces a solenoid valve into the gas train after the water trap
connection to the Quintox. With the purge turned OFF the instrument will draw gas
from the probe and flue, with purge ON the solenoid is activated and the instrument
draws fresh air from within its case. The solenoid can be switched either manually or
through a timed operation.
Manual Operation
This function allows the user to switch the solenoid ON or OFF manually through
pressing a sequence of keys. It can be performed at any time during Quintox operation
but has no effect during a timed operation.
ON/OFF Toggle operation
Timed Operation
This requires the user to set the following :-
Purge duration - The amount of time fresh air is draw into the instrument. This can
be set between 5 and 30 minutes and is a function of the gas concentration and the
humidity of the ambient air. For dry ambient conditions and high gas concentrations a
longer purge duration should be set.
Purge interval - This is the time between purge operation, i.e. the time the instrument
is sampling gas. It can be set between 9 and 99 minutes.
Auto zero - Allows all toxic cells to be set to zero and the oxygen cell to 20.9% on
completion of the purge cycle. i.e. if 10 minutes is set in the ‘Purge duration’
following this time the cells would be Auto zeroed. Note sufficient time must be
allowed for the cells to return to zero, if concentrations of gas are high then a long
purge duration should be set.
NOTE: If the analyser is positioned where levels of gases are higher than fresh air
ambient conditions then auto zero should not be used.
NOx
AUX
SET/CAL
ENTER