Data Sheet for Product

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Siemens Control device PN25, safety function to DIN EN 14597 CE1N4387en
Building Technologies 2020-04-29
0 100 200 300 400 500 600 700 800 900 10001100 1200 1300
25
20
15
10
5
0
2500
2000
1500
1000
500
0
P
1
[kPa]
P
1
[bar]
D
p
max
[kPa]
4382D05
1
4
0
°
C
1
8
0
°
C
1
6
0
°
C
1
2
0
°
C
1
0
0
°
C
8
0
°
C
J
Dp
max
= Differential pressure with valve almost closed, at
which cavitation can largely be avoided
p
1
= Static pressure at inlet
p
3
= Static pressure at outlet
M = Pump
J = Water temperature
p
3
p
1
4
3
8
2
Z
0
6
D
p
max
M
Pressure p
1
at valve inlet: 500 kPa (5 bar)
Water temperature: 120 °C
From the diagram above, it will be seen that with the valve almost closed,
the maximum permissible differential pressure Dp
max
is 200 kPa (2 bar).
Spring water cooling as an example of avoiding cavitation:
Chilled water = 12 °C
p
1
= 500 kPa (5 bar)
p
4
= 100 kPa (1 bar)
(atmospheric pressure)
Dp
max
= 300 kPa (3 bar)
Dp
3-3’
= 20 kPa (0.2 bar)
Dp
D
(throttle) = 80 kPa (0.8 bar)
p
3
’ = pressure after
consumer in kPa
p
3
p
1
4
3
8
2
Z
0
7
D
p
max
M
p
3
'
Dp
D
p
4
High temperature
hot water example:
Chilled water
example: