Nominal Size Selection Calculation Formula; Installation; Example Of Piping - Yoshitake GP-2000 Installation & Operation Manual

5.5 Nominal size selection calculation formula

The appropriate nominal size can be calculated by obtaining the Cv value for the operating
conditions in question, as shown below.
• Cv value calculation formula
P
1
>
P
2
2
Cv
P
< 1
P
2
2
Cv =
• Rated Cv value table
Nominal size 15A 20A
Rated Cv value
0.01 MPa set 2.5
*Please consults factory for internal sensing method valves.
[Flow rate calculation example of GP-2000 pressure reducing valve]
The flow rate of the pressure reducing valve is calculated under the following conditions:
Nominal size 15A, saturated steam, Inlet pressure of 0.6 MPa, Reduced pressure of 0.4
P
MPa. =0.7 [MPa A],
1
The following formula is established.
=
P ( . 0 ) 5
2
W
■ Secure a safety rate of 80 to 90%

6. Installation

6.1 Example of piping

Wk
=
∆ +
138 P(P P
1 2
Wk
120P
1
25A 32A 40A 50A 65A 80A
5 7.2 10.9 14.3 18.8
3.6 5.4 7.1
P
=0.5 [MPa A], you can find that Cv value of 15A is 5 from the chart.
2
=
P ( . 0 ) 7
1
>
W
2
∆ +
13 5 . Cv P P ( P )
1 2
=
k
W: Max. steam flow rate [kg/h]
P : Inlet pressure [MPa･A]
1
P : Reduced pressure [MPa･A]
2
)
ΔP: P
k: 1+0.0013 × {super-heated steam
32 54
9.4 16 27
∆ +
138 Cv P ( P P
1
=
k
× ×
138 5 0 2 .
=
1
-9-
－P
[MPa]
1 2
temp.[℃]－saturated steam
temp.[℃]}
100A 125A
70 108 112
35 54 -----
)
2
× +
0 ( 7 . . 0 ) 5
=
338
150A 200A
225 234
----- -----
kg / h
■EPDT-014f■