Boiler house
Bottom blowdown systems
Differential pressure (ΔP)
across the valve
Minimum air pressure bar g
DN15 - DN25
DN32 - DN50
DN65
10 bar g
0.7 1.8 4.5
15 bar g
0.9 2.6
20 bar g
1.1 3.3
25 bar g 1.2 4.0
30 bar g
1.4 4.7
32 bar g
1.4 5.0
42 bar g
1.7
63 bar g 2.4
68 bar g
2.6
80 bar g
2.9
100 bar g
3.6
2.11.5
Size DN15 DN20 DN25 DN32 DN40
DN50
DN65
Kv 1.6 2.5 4 4 6.3
10 16
Pressure (bar)
0 0.0 0.0 0.0 0.0 0.0
0.0
0.0
0.5 1.1 1.8 2.8 2.8 4.5
7.1 11.3
1 1.6 2.5 4.0 4.0 6.3
10.0
16.0
10 5.1 7.9 12.6 12.6 19.9
31.6
50.6
20 7.2 11.2 17.9 17.9 28.2
44.7
71.6
30 8.8 13.7 21.9 21.9 34.5
54.8
87.6
40 10.1 15.8 25.3 25.3 39.8
63.2
101.2
50 11.3 17.7 28.3 28.3 44.5
70.7
113.1
60 12.4 19.4 31.0 31.0 48.8
77.5
123.9
70 13.4 20.9 33.5 33.5 52.7
83.7
133.9
80 14.3 22.4 35.8 35.8 56.3
89.4
143.1
90 15.2 23.7 37.9 37.9 59.8
94.9
151.8
100 16.0 25.0 40.0 40.0 63.0
100.0
160.0
DN65
DN50
DN40
DN25-32
DN20
DN15
Minimum air pressure / Differential pressure
Capacities
Page 4 of 17
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Pressure (bar)
TI-P405-51 AB Issue 1
BBV Automatic or Manually Actuated Boiler Blowdown Valves DN15 to DN65
C
a
p
a
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(
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