A-9
Reference Data
Pressure Loss
The approximate pressure loss from the flowmeter can be
determined using the following equations:
English
Metric
where:
NOTE
Pressure loss is 1.8
D
P for the dual sensor meter.
Minimum Back Pressure (Liquids)
Flow metering conditions that would allow cavitation, the release of
vapor from a liquid, should be avoided. This flow condition can be
avoided by remaining within the proper flow range of the meter and by
following appropriate system design.
For some liquid applications, incorporation of a back pressure valve
should be considered. To prevent cavitation, the minimum back
pressure should be:
NOTE
Pressure loss is 1.8
D
P for the dual sensor meter.
D
P = Pressure loss (psi or kPa)
f
= Density at operating conditions (lb/ft
3
or kg/m
3
)
D = Flowmeter bore diameter (in. or mm)
Q
gpm or lpm
= Actual volumetric flow rate (gal/min or l/min)
Q
acfm or acmh
= Actual volumetric flow rate (ft
3
/min or m
3
/hour)
P =
2.9
D
P + 1.3 p
v
P = Line pressure five pipe diameters downstream of the meter
(psia or kPa abs)
D
P= Pressure loss across the meter (psi or kPa)
p
v
= Liquid vapor pressure at operating conditions (psia or kPa
abs)
/L TXL GV
()D
3
x
–
()
x
r
I
x
4
JSP
()
'
*DVHV
()D
3
x
–
()
x
r
I
x
4
DFIP
()
'
/LTXLGV
()D
3
()
x
r
I
x
4
OSP
()
'
*DVH V
()D
3
()
x
r
I
x
4
DFPK
()
'
To Next Page
Loading...
