Data Sheet for Product

5
Siemens A6V10960349_en--_c
Smart Infrastructure 2021-02-23
Cavitation
Cavitation increases wear and tear on the parabolic plug and seat and results in unwanted
noise. Cavitation can be prevented by not exceeding the differential pressures as per the
flow diagram and maintaining the static pressures depicted below.
0 100 200 300 400 500 600 700 800 900
1000
1100
1200
1300
25
20
15
10
5
0
2500
2000
1500
1000
500
0
1
4
0
°
C
1
8
0
°
C
1
6
0
°
C
1
2
0
°
C
1
0
0
°
C
8
0
°
C

Δp
max
=
Differential pressure at a nearly closed valve
to largely avoid cavitation
p
1
= Static pressure and the valve inlet
P
3
= Static pressure and the valve outlet
M Pump
J Water temperature
Example with hot water:
Pressure p
1
at valve inlet: 500 kPa (5 bar)
Water temperature: 120 °C
The above diagram clearly indicates that the maximum permissible differential pressure is
Δp
max
→ 200 kPa (2 bar) at a nearly closed valve.
Note on chilled water applications
To prevent cavitation in chilled water circuits, sufficient counter pressure must be supplied to
the valve output, e.g. using an additional butterfly valve downstream of the valve. Maximum
permissible differential pressure over the valve: See 80 °C curve in the above diagram.