How to calculate the vortex flow meter minimum velocity in gas, steam and liquid applications
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Vortex flow meter mininum velocity in normal gas, air systems
Qρ =Q0×√(ρ 0 /ρ )
Qρ : measureable lower limit under medium’s density
Q0:the lower limit
ρ 0:density reference to air ρ 0=1.205kg/m3
ρ :density of measured medium
Remark: for lower density and high viscosity like H2, the measurable limit will be more high and vortex meter may not suitable for this case. Only when working pressure is high.
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Vortex flow meter mininum velocity in liquid measurement
Vortex meter the ideal model for liquid application due to no moving parts and very low pressure drop, velocity range is 0.3~7m/s. For other liquid in high need to confirm the viscosity.
DN15≤4mPas; DN25≤5mPas; DN40~DN300≤7mPas;
Unit transfer: 1 cp=1mPa·s; 100 cp=1p;
1 cst=1mPa·s /g/cm3 ; 1cst=1mm2/s
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Vortex flow meter mininum velocity in steam mass measurement
As a normal rule, we also use T/hr or kg/hr as the mass unit for steam measurement. Because of the temperature and pressure are different under saturated steam and superheated steam so the steam measureable range will be different.
Q=1.5Q0×=√(ρ 0/ρ )×ρ ×10-3(t/h)
ρ ,the measured medium’s density
Q:the measured medium’s flow rate
ρ 0,Q0:the referenced air’s density(1.205kg/m3) and flow
For example: counting the flow range under DN100, pressure at 8barG
Step 1, counting the volume range under DN100, that is 100 — 1000m3/h
Step 2, check the density under pressure 8barG, is ρ=4.162kg/m3
Step3, counting the lower limit of DN100,
Q=1.5×100×√(1.205/4.162)×4.162×10-3
=0.336 (t/h)
Step 4, counting the upper limit, not large than 70m/s
Remark: if medium is superheated steam, need to confirm the temperature and pressure both and confirm the density then.
