YOKOGAWA VY Series Manual

<3. Maintenance>
20
IM 01F07A01-02EN
b) Gas
In the case of gas, perform temperature/pressure correction based on the measured
temperature value, and calculate the volumetric ow rate at normal conditions. For the
pressure, use the xed value input in the parameters or the analog input value from an
external pressure gauge.
Q
n
= Q
f
×{P
f
/ P
n
}×{(T
n
+273.15) / (T
ft
+273.15)}×1 / K
c) Liquid
In the case of liquid, perform a secondary correction for the change in density based on the
temperature.
For the calculation, use the measured temperature value to determine the change in
density.
M = Q
f
×ρ
n
×{1+a1 × (T
ft
-T
n
)×10
-2
+a
2
× (T
ft
-T
n
)
2
×10
-6
}
[Additional notes]
a
1
= {(k
1
-1)×∆T
2
2
-(k
2
-1)×∆T
1
2
} / {(∆T
1
×∆T
2
2
-∆T
2
×∆T
1
2
)×10
-2
}
a
2
= {(k
1
-1)×∆T
2
-(k
2
-1)×∆T
1
} / {(∆T
1
2
×∆T
2
-∆T
2
2
×∆T
1
)×10
-6
}
k
x
= 1+a
1
×∆T
x
×10
-2
+a
2
×∆T
x
2
×10
-6
∆T
x
= T
x
-Tn
(x = 1, 2)
M: Mass ow rate
Q
n
: Volumetric ow rate at normal conditions
Q
f
: Volumetric ow rate at operating conditions
T
f
: Temperature at operating conditions (°C)
T
ft
: Measured temperature (°C)
T
n
: Temperature at normal conditions (°C)
P
f
: Pressure at operating conditions (kPa)
P
n
: Pressure at normal conditions (kPa)
K: Deviation factor
ρ
n
: Density at normal conditions (kg/m
3
)
ρ
f
: Density at operating conditions (kg/m
3
)
ρ
ft
: Density determined from measured temperature (kg/m
3
)
U
ρf
. Density unit conversion coe󰀩cient
U
k
(kg), U
k
(Nm
3
), U
k
(m
3
): Flow rate unit conversion coe󰀩cient
a
1
: Primary correction coe󰀩cient for liquid
a
2
: Secondary correction coe󰀩cient for liquid
(Example) Using U
k
(kg) coe󰀩cient to convert unit from kg
For kg: U
k
(kg) = 1
For metric ton: U
k
(kg) = 0.001

YOKOGAWA VY Series Specifications

General

Brand	YOKOGAWA
Model	VY Series
Category	Measuring Instruments
Language	English