Section 3
Theory of Operation
3-11
substituting equation 3-22 into 3-23 and following through the derivation,
the calibration equations for CO
2
become:
Vr
(wr )F
1
cr
(wr )
T
273
T 273
P
P
o
o
=
−
+
+
χ
χ
G 1
V
K
r
= −
3-30
C
w F
VG V
w
P
P
T
T
s
r
s
o
o
=
+
+
+
χ
χ
(
)
(
)
273
273
∆
C = C - C
r
The water correction is based upon a theoretically justifiable procedure
which requires determination of a single physically meaningful constant, and
can be applied to any LI-COR 6200 series infrared gas analyzer, and perhaps
others, as well.
3.6 Dilution Corrections
A dilution correction can be applied in the LI-6262, if desired. When one
component gas of multicomponent mixture is decreased at constant pressure,
the partial pressures of all other components are increased accordingly. For
example, if water vapor is removed at constant pressure, then the partial
pressures of other components increase according to
P
p
w
i
wet
=
∑
−
(
/
)
1
1000
3-31
where w is the water vapor mole fraction (mmol/mol) and the p
i
wet
are
partial pressures of other component gases before water vapor was removed.
For individual components, Equation 3-31 becomes
p
p
w
i
dry
i
wet
=
−
(
/
)
1
1000
3-32
