Series RSS/F
Page
7
9560-010-en
Revision 19
TM 10477
Edition 05/2022
1.6 Cavitation coefficient z
Kv / Kv
100
= 75%
DN
Seat - ø in mm
[mm] [inch]
8
14
15
20
25
30
40
50
65
80
96
120
120
145
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
150
6“
0.23
0.20 0.18
𝑋
𝐹
=
∆𝑝
𝑝
1
−𝑝
𝑣
1.7 Valve travel
DN
Standard PTFE bellows
Heavy duty PTFE-
bellows
Hastelloy bellows
[mm]
[inch]
[mm]
[mm]
[mm]
[mm]
[mm]
[mm]
[mm]
[mm]
[mm]
15
½“
15
20
15
20
20
¾“
15
20
15
20
25
1"
15
20
15
15
20
40
1½"
15
20
30
15
20
15
20
50
2"
15
20
30
15
20
15
20
65
--
15
20
30
15
20
15
20
80
3"
30
30
30
100
4"
30
30
30
150
6“
--
--
--
50
--
--
--
The valve travel depends on the actuator selected.
XF = Differential pressure ratio
Δ
p = Differential pressure input/outlet
p1 = Absolute pressure at inlet
pv = Vapour pressure at operating temp.
XF
≤ z
: non-critical conditions
XF
≤ 1,4 x z
: tolerable cavitation
XF
> 1,4 x z : inadmissible cavitation
