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4.13.3 Gas train
Type-approved in accordance with EN 676 and supplied
separately from the burner.
4.13.4 Gas train installation
Disconnect the power supply using the system
main switch.
DANGER
Check that there are no gas leaks.
Pay attention when handling the train: danger of
crushing of limbs.
Make sure that the gas train is properly installed
by checking for any fuel leaks.
The operator must use the required equipment
during installation.
The gas train is pre-arranged to be connected to the burner at the
flange 2)(Fig. 26).
1
2
Data of head thermal power and gas pressure
refer to operation with gas butterfly valve fully
open (90°).
ATTENTION
20121588
Installation
4.13.5 Gas pressure
Tab. I indicates the pressure drops of the combustion head and
gas butterfly valve depending on the burner operating output.
kW
5000
5500
6000
6500
7000
7500
8000
8500
9000
9500
The values shown in Tab. I refer to:
–
Natural gas G 20 NCV 9.45 kWh/Sm
–
Natural gas G 25 NCV 8.13 kWh/Sm
Column 1
Combustion head pressure drop.
Gas pressure measured at test point 1)(Fig. 26), with:
•
combustion chamber at 0 mbar;
•
burner working at maximum modulating output;
•
combustion head adjusted as in page 26.
Column 2
Pressure drop at gas butterfly valve 2)(Fig. 26) with maximum
opening: 90°.
To calculate the approximate output at which the burner
operates:
–
subtract the combustion chamber pressure from the gas
pressure measured at test point 1)(Fig. 26).
–
Find in Tab. I related to the burner concerned, the pressure
value closest to the result of the subtraction.
Read the corresponding output on the left.
Example with natural gas G20:
Operation at maximum modulating output
Gas pressure at test point 1)(Fig. 26)
Pressure in combustion chamber
A pressure of 46.4 mbar (column 1) corresponds in Tab. I to an
output of 9000 kW.
This value serves as a rough guide; the effective output must be
measured at the gas meter.
To calculate the required gas pressure at test point 1)(Fig. 26),
set the maximum modulating output required from the burner op-
eration:
–
find the nearest output value in Tab. I for the burner in ques-
tion.
–
read, on the right (column 1), the pressure at the test point
Fig. 26
1)(Fig. 26).
–
Add this value to the estimated pressure in combustion
chamber.
Example with natural gas G20:
Operation at maximum modulating output
Gas pressure at an output of 9000 kW
Pressure in combustion chamber
pressure required at test point 1)(Fig. 26).
23
GB
1 p (mbar)
G 20
G 25
G 20
16.0
23.2
1.8
19.1
27.6
2.2
22.1
32.0
2.6
25.2
36.3
3.1
28.9
41.6
3.6
32.9
47.2
4.1
36.9
52.7
4.7
41.5
59.4
5.3
46.4
66.3
5.9
51.2
73.3
6.6
3
(8.2 Mcal/Sm
3
(7.0 Mcal/Sm
56.4 - 10
46.4 + 10
2 p (mbar)
G 25
2.7
3.3
3.9
4.6
5.3
6.1
7.0
7.9
8.8
9.8
Tab. I
3
)
3
)
= 56.4 mbar
=
10 mbar
= 46.4 mbar
= 46.4 mbar
=
10 mbar
= 56.4 mbar
20169350
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