14
INM MTL 130-0202 Rev 4
IMPORTANT NOTES
1. When calibrating, it is important to maintain a steady flow of calibration gas. For all gases, except
the hydrogen in air mixture, flows of up to 400ml/min are acceptable. For hydrogen in air mixtures
the flow must be limited to no more than 100ml/min (100ml/min = 0.212cuft/hr). This is because
the reaction time of hydrogen with the oxygen in the air is somewhat slower than the reaction of
hydrogen with the chlorine in the process gas. Its longer residence time in the reactor at the lower
flow rate ensures complete reaction. Allow enough time for the sample system to be purged of
each gas and for the instrument to stabilise between each gas by flowing each one for 10 to 15
minutes.
2. When using argon to calibrate chlorine span the calibration screen displays % argon. When
returning to normal Measurement Mode from Calibration Mode with argon still flowing, the
chlorine concentration displayed will be the argon equivalent for that particular katharometer.
This figure varies from 33% to 35%. The precise point varies slightly from one katharometer to
another, and the exact figure is a part of the katharometer’s characteristics that are contained in the
Katharometer Identity Module (KIM). This figure is used by the software to set the 100% chlorine
point from the 100% argon point. The following diagram illustrates this graphically in terms of the
thermal conductivities of the three gases.
Thermal Conductivity
Air
Chlorine
Argon
100% of span
33/35% of span
5.3 Calibration mode
Refer to calibration screen map on next page
View
Edit
Cal
HITECH INSTRUMENTS
Luton England.
Hydrogen in Chlorine Analyser
Press
Cal
key for
appoximately
8 seconds to
access calibration
Press
Meas cal gas
key after each
calibration gas has
been passed for 10
to 15 minutes and
the reading is stable
Meas
cal
gas
This screen
appears when
calibration mode
is entered
Calibration mode
Surrogate
Nonsurrogate
VIEW to exit
View
Edit
Cal
Meas
Cal
Gas
2
L
A
2
L
A
1
L
A
AL1
Hydrogen in Chlorine Analyser
KK650 MTL Hydrogen in Chlorine Analyser
