Operation Manual
    <13. GENERAL SPECIFICATIONS>
13-15
IM 01F06A00-01EN
 Calculation formula
 How to calculate volume fl ow rate at operating 
conditions.
• Q
f
 = 3600××S or Q
f
 = 
×D
2
354
 How to calculate the velocity of a Reynolds 
number.
• = 5× / D (Reynolds number of 5000)
• = 20× / D (Reynolds number of 20000)
• = 40× / D (Reynolds number of 40000)
where
• Re = 
354×10
3
×Q
f
×D
 ········· (1)
•  = 
f
 ×10
3
 ················ (2)
 Q
f
: Volume fl ow rate at operating conditions 
(m
3
/h)
 D:  Inner diameter of digitalYEWFLO (mm)
 S:  Sectional area of digitalYEWFLO (m
2
)
 :  Flow velocity (m/s)
 Re: Reynolds number (non unit)
f
:  Density at operating conditions (kg/m
3
)
 :  Viscosity at operating conditions (mPa·s (cP) )
 : Kinematic viscosity at operating conditions 
(10
-6
m
2
/s (cSt) )
 Typical fl uid example
Table 13.8  Range of Measurable Water Flow Rate
(At standard condition of 15°C,  = 1000 kg/m
3
)
Model Code 
Measurable Flow Rate 
in m
3
/h 
Range of Fixed 
Accuracy Flow Rate 
in m
3
/h 
DY015 DY025/R1   DY040/R2  0.30 to 6  0.94 to 6 
DY025  DY040/R1   DY050/R2  0.65 to 18  1.7 to 18 
DY040  DY050/R1   DY080/R2  1.3 to 44  2.6 to 44 
DY050  DY080/R1   DY100/R2  2.2 to 73  3.3 to 73 
DY080  DY100/R1   DY150/R2  4.3 to 142  4.6 to 142 
DY100  DY150/R1   DY200/R2  7.5 to 248  7.5 to 248 
DY150  DY200/R1   —  17 to 544  18 to 544 
DY200  —  —  34 to 973  34 to 973 
DY250  —  —  60 to 1506  60 to 1506 
DY300  —  —  86 to 2156  86 to 2156 
DY400 — —  177 to 3547 177 to 3547










