Data sheet
VFS 2
VD.HC.L3.02 | 5
© Danfoss | 2016.11
m
as
s f
lo
w o
f s
at
ur
at
ed w
at
er s
te
am (
kg
/h
)
m
as
s f
lo
w o
f s
up
er
he
at
ed w
at
er s
te
am (
kg
/h
)
Sa
tu
ra
te
d
Sre
am
T
emp
er
atu
re
A
bs
ol
ut
e Inl
et
P
res
sur
e
Critical Pressure Drop (kPa)
Superheat °C
Crit
ica
l Pr
ess
ure D
rop (
kPa
)
Steam valve sizing is based on 40 % of the
absolute steam pressure (immediately upstream
of the valve), being dropped across the valve
when fully open. At this condition the steam
is travelling at or close to its critical velocity
(approx. 300 m/s) and throttling will occur over
the full valve stroke. If the steam is travelling
slower than this then the first part of the valve
stroke will merely increase the velocity of the
steam without reducing the volumetric flow.
Control valve sizing diagram for steam
Max. Δp in low pressure steam application variance from 0.5 bar to 6 bar (see page 2)