FCU 500, FCU 505 · Edition 02.17
51
Valve proving system
Calculation example
Nominal flow rate Q
(N)
:
P (kW): capacity = 1000 kW
H
u
(kWh/m
3
):
lower calorific value of gas type = 10 kW/m
3
Q
(N)
(m
3
/h) =
P (kW)
H
u
(kWh/m
3
)
Q
(N)
(m
3
/h) =
1000 kW
= 100 m
3
/h
10 kWh/m
3
Max. gas volume in combustion chamber V
O
:
V
O
(l/h) = Q
(N)
×
0.05%
Q
(N)
(m
3
/h): nominal flow rate = 100 m
3
/h
(100,000 l/h)
V
O
(l/h) = 100,000 l/h
×
0.05% = 50 l/h
Required opening time t
L
:
t
L
(s) =
400 ×
V
O
×
√
ρ
π
×
d
2
×
0.7
2 ×
p
u
V
O
(l/h):
max. gas volume in combustion chamber = 50 l/h,
d (mm): orifice diameter of bypass valve = 9.45 mm,
flow factor = 0.7,
p
u
(mbar): inlet pressure = 20 mbar,
ρ
(kg/m
3
): density of gas = 0.8 kg/m
3
t
L
(s) =
400 ×
50 l/h
×
√
0.8 kg/m
3
= 14.26 s
3.14
×
9.45
2
×
0.7
2 ×
20 mbar
Enter the next lowest value for parameter 59 (P59 = 14)
to set the opening time, see page 112 (Valve opening
time 1 t
Calculation module for calculating the opening time t
L
,
see page 52 (Calculating the extended valve open-
ing time)
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