4
■
EPDT-251b
■
6. Nominal Size Selection
6.1 Nominal size selection chart
■
For water (Cv = 1)
First calculate pressure loss
∆
P and then find flow rate V in the above chart. Secondly, multiply the flow
rate V by Cv value for each model.
[Example]
•
Model: DD-3 (Cv value: 1.7)
•
Inlet pressure (P
1
): 0.15 MPa
•
Outlet pressure (P
2
): 0.05 MPa
Pressure loss is calculated as
∆
P = P
1
- P
2
= 0.1 MPa. Then, find the flow rate V = 14 L/min as shown
by the dashed lines in the above chart. Next, multiply V = 14 L/min by the Cv value of 1.7.
Therefore:
14 L/min x 1.7 = 23.8 L/min
V
:
F
lo
w
r
a
te
(
L
/m
in
)
∆
P: Pressure loss (MPa)
