BRONKHORST CORI-TECH B.V.
4.5.2 For Liquids
Determine desired
∆
p across valve.
∆
p must be at least 50% of supply pressure
Kv-value calculation
1000
p
K
m
v
⋅
∆
Φ
=
ρ
ρ
Units:
flow
-
)
/h
(
kg
m
Φ
density
-
ρ
(kg / m ) at 20 C
3
and 1 atm.
delta p
-
∆
p(bard)
The orifice bore diameter can be determined by:
d 7.6 K
v
=
[mm]
For C2 type of valves the diameter of the orifice can be calculated as shown above or looked up in the graph
below.
Φ
Φ
v 2
v
2
H O =
customer
customer
H O
ρ
ρ
in which:
Φ
v
= volume flow
ρ
= density
If liquids have viscosity’s >15 cs (water = 1 cs), the flat orifice and plunger type control mechanism cannot be
used. For measuring systems only check maximum possible viscosity with factory.
4.6 Calibration procedure
All instruments are factory calibrated. For re-calibration or re-ranging contact supplier or factory.
10
4
10
3
10
1
10
-1
10
1
10
0
10
4
10
3
10
2
10
1
P (bar)
d = 0.1 mm
d = 0.37 mm
d = 0.3 mm
d = 0.2 mm
d = 0.14 mm
10
2
10
0
10
-2
O
H O (ml/h)
2
10
-1
10
1
10
0
d = 1.0 mm d = 0.7 mm
d = 0.5 mm
P max.
v
page 24
9.17.031
