Volumetric Flow Rate Measurement - ABB CK-MAG 10D1477 Instruction Manual

10D1477 MAGNETIC FLOWMETER INSTRUCTION MANUAL

4.1.3 Volumetric Flow Rate Measurement

The magnetic flowmeter is a volumetric flow rate measuring instrument. This can be shown by
substituting the physical equivalent of liquid velocity into equation #1, preceding, as follows:
(Equation #2)
V = Q = 4Q
A
Substituting for V in equation #1
= 1 BD
E
s
α
and solving for Q:
Q = παD
∴
Since B = βE
r
and since α, D and β are constant:
(Equation #3)
Q = γ E
where:
Q = volumetric flow rate
A = cross-sectional area
D = pipe section diameter
E = induced signal voltage
s
E = reference voltage
r
B = magnetic flux density
α = dimensionless constant
β & γ = dimensional constant
V = liquid velocity
Volumetric flow rate is directly proportional to the induced signal voltage as measured by the
magnetic flowmeter.
πD
2
4Q
πD
2
2 .
E s
4 B
s
E
r
4-3