Datasheet

Front matter 5
Solenoid Valves Flow Characteristics
(How to indicate flow characteristics)
Conversion of flow coefficient:
Av = 28 x 10
–6
Kv = 24 x 10
–6
Cv ···········································································(11)
Here,
Kv factor: It is the value representing the flow rate of clean water in m
3
/h which runs through the valve at 5 to 40°C, when the
pressure difference is 1 bar.
Cv factor (Reference values): It is the value representing the flow rate of clean water in US gal/min which runs through the valve
at 60°F, when the pressure difference is 1 lbf/in
2
(psi).
Values of pneumatic Kv are different from Cv because the testing method is different from each other.
Example 1)
Obtain the pressure difference when 15 [l/min] of water runs through the solenoid valve with an Av = 45 x 10
–6
[m
2
].
Since
Q
0
= 15/45 = 0.33 [l/min], according to the Graph (2), if reading ∆
P
when
Q
0
is 0.33, it will be 0.031 [MPa].
Example 2)
Obtain the flow rate of saturated aqueous vapour when
P
1
= 0.8 [MPa], ∆ P = 0.008 [MPa] with a solenoid valve with an Av =1.5 x
10
–6
[m
2
].
According to the Graph (2), if reading
Q
0
when P
1
is 0.8 and ∆ P is 0.008, it is 0.7 [kg/h]. Hence, the flow rate Q = 0.7 x 1.5 = 1.05
[kg/h].
Water flow rate
Q
0
[
l
/min] (When
Av
= 1 x 10
–6
[m
2
])
Saturated aqueous vapour flow rate
Q0
[kg/h] (when
Av
= 1 x 10
–6
[m
2
])
Pressure differential
∆
P
[MPa]
Upstream pressure
P1 = 1MPa
P1 = 0.8MPa
P1 = 0.6MPa
P
1 = 0.5MPa
P
1
= 0.1MPa
P1
= 0.2MPa
P1
= 0.4MPa
Ex. 2
Ex.
1
Graph (2) Flow characteristics line
3
2
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
3
2
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.001
0.040.030.02
0.01
0.0040.003
0.002
0.1
P
1
= 0.3MPa