5．When tested gas is vapor，often use quality flow as unit of measurement quality flow，as：t/h or Kg/h. because of vapor（overheating & saturated）,density would be changed under different temp & press，so to ensure the flow range, see (8)
Ρ:density of vapor (kg/m3)
Q steam:quality flow of vapor (t/h)
6.For pressure loss, check the effect of pressure loss to craft pipeline,(Unit: Pa):
Δp= CdρV2/2 formula（9）
P: density of medium under working condition (9kg/m3)V: mean flow rate(m/s)
7.If tested medium is liquid, to avoid is Δp: pressure loss (Pa) Cd:coefficient of pressure loss.
classifications and loss, shall make the press of pipeline as follow:
Tips: Δp: pressure loss(Pa)
p0: saturated vapor pressure of liquid which under working temperature.
(Pa absolute pressure) Po: Fluid vapor pressure (Pa absolute pressure)
8. Vortex flow meter flow meter is not suitable for testing high viscosity liquid. if counted measurable lower limit flow is not suitable for designing, pls select and use other meter type.
9．If as the counted parameter, the two or more kinds of meter can be used, then use less caliber, cheaper. Tips: as far as possible tested range during upper limit of about 1/2～2/3.
Chart(II) extent table of reference condition under working condition
Tips：above table the caliber (300)~(1000) is plug-in