EF200W-C
10
The effective lower range value Q
Low
is determined using the largest of the three values Qmin,
Q
[m /h] = max
Low
³
Q
[m /h]
min
³
Q
[m /h]
Re = 5000
³
Q
[m /h]
AmpMin
³
Low
³
Q
[ /min]
min
Q
[ /min]
Re = 5000
Q
[ /min]
AmpMin
A0034313
Q
Low
Effective lower range value
Q
min
Minimum measurable flow rate
Q
= 5000
Flow rate is dependent on the Reynolds number
Q
AmpMin
Minimum measurable flow rate based on signal amplitude
Upper range value
The measuring signal amplitude must be below a certain limit value to ensure that the signals can be
evaluated without error. This results in a maximum permitted flow rate Q
AmpMax
:
Q
[m /h] =
AmpMax
³
350 [m/s] · · D [m]
i
²
π
· 3600 [s/h]
4 ·
³]
m
/
g
k
[
ρ
³]
m
/
g
k
[
1
Q
[ /min] =
AmpMax
³
1148 [ /s] · · D [ft]
i
²
π
· 60 [s/min]
4 ·
0.0624 [lbm/ ]
³
A0034316
Q
AmpMax
Maximum measurable flow rate based on signal amplitude
D
i
Internal diameter of measuring tube (corresponds to dimension K→ See page 34)
ρ
Density
For gas applications, an additional restriction applies to the upper range value with regard to the
Mach number in the measuring device, which must be less than 0.3. The Mach number Ma describes
the ratio of the flow velocity v to the sound velocity c in the fluid.
Ma =
v [m/s]
c [m/s]
Ma =
A0034321
Q
Re =5000
and Q
AmpMin
.
