5 flow values, kv100 (cv), 6 cavitation coefficient z, Flow values, kv100 (cv) – Richter RSS/F Series Bellows-Sealed Control Valves User Manual
Page 6: Cavitation coefficient z, Series rss/f
Series RSS/F
Page 6
9260-060-en
Revision 03
TM 7168
Edition 06/2008
1.5 Flow values, kv100 (Cv)
V- and Parabolic plugs
Nominal
size
Kv100
Cv
Seat -
in mm
[
mm] [inch]
8
8
8
8
8
8
14 14 14 14 14 14 15 20 25
15
½“
m
3
/h
USgpm
0,05
0.06
0,10
0.12
0,20
0.23
0,50
0.58
0,80
0.93
2
2,3
4
4,7
20
¾“
m
3
/h
USgpm
0,05
0,06
0,10
0.12
0,20
0.23
0,50
0.58
0,80
0.93
2
2,3
4
4,7
25 1“
m
3
/h
USgpm
2
2,3
0,05
0,06
0,10
0.12
0,20
0.23
0,50
0.58
0,80
0.93
1,20
1.40
4
4,7
7
8,2
11
12,8
Nominal
size
Kv100
Cv
Seat -
in mm
mm] [inch]
15 20 25 30 40 50 65 80 96
40 1½“
m
3
/h
USgpm
4
4,7
7
8,2
11
12,8
15
17,5
28
32,6
50 2“
m
3
/h
USgpm
7
8,2
11
12,8
15
17,5
28
32,6
42
48,9
65 --
m
3
/h
USgpm
7
8,2
11
12,8
15
17,5
28
32,6
42
48,9
80 3“
m
3
/h
USgpm
15
17,5
28
32,6
42
48,9
65
75,7
100
117
100 4“
m
3
/h
USgpm
42
48,9
65
75,7
100
117
155
180
U-Plugs
DN
Seat -
in mm [inch]
[mm] [inch]
80 [3.15]
96 [3.78]
80
3"
90 m
3
/h
105 USgpm
100
4"
90 m
3
/h
105 USgpm
135 m
3
/h
157 USgpm
Notes:
The next lower kv100/Cv value can also be achieved
with special plugs without changing the seat .
This is important if the kv100/Cv value is subsequently
changed as only the plug then has to be replaced.
Conversion into Cv (US gpm) = kv100 x 1,165.
1.6 Cavitation coefficient z
K
v
/ K
v100
= 75%
DN
Seat -
in mm
[mm]
[inch
]
8
14
15 20 25 30 40 50 65 80 96
15 ½“ 0,60 0,60 0,60
20 ¾“ 0,60 0,60 0,60
25 1" 0,60 0,60 0,60 0,60 0,60
40 1½"
0,60 0,60 0,60 0,55 0,50
50 2"
0,60 0,60 0,55 0,50 0,40
65 --
0,60 0,60 0,55 0,50 0,40
80 3"
0,55 0,50 0,45 0,32 0,30
100 4"
0,47 0,33 0,30 0,26
v
1
F
p
p
p
X
=
X
F
= Differential pressure ratio
p
= Differential pressure inlet/outlet
p
1
= Absolute pressure at inlet
p
v
= Vapour pressure at operating temperature
X
F
z
: non-critical conditions
X
F
1,4 x z : tolerable cavitation
X
F
> 1,4 x z : inadmissible cavitation