Technical description of the burner
11
20029324
3.8
Firing rates
The maximum output is chosen within area
A
of the diagram
(Fig. 4).
The
minimum output
must not be lower than the minimum limit of
the diagram.
The firing rates were obtained in special test boilers. Fig. 5 indi-
cates the diameter and length of the test combustion chamber.
Example
Output 2579 MBtu/hr:
diameter = 23.6 inch; length 6.6 ft
The RS 68/E LN - RS 120/E LN burners are suitable for operation
on either flame-inversion boilers
*
or boilers with combustion cham-
bers featuring flow from the base (three flue passes) on which the
best results are obtained in terms of low NOx emissions.
The maximum thickness of the boiler’s front door must not exceed
8” (see fig. C).
(
*
) For flame inversion boilers, a kit is available to reduce CO emis-
sions if required.
The kit includes 5 gas pipes, identical to the other 5 already fitted
to the burner head. In standard conditions, the burner head is fitted
with a second group of pipes, with gas outlet in a different direction
with respect to the others. With this Kit, the second group of pipes
is replaced, so that all the pipes are the same. After fitting the kit,
ensure they work correctly by measuring the CO and flue gases
emissions.
3.8.1
Procedure to refer burner operating condition
in high altitude plants
Find the
corrected burner capacity
for the plant’s altitude in chart
1
and the
corrected pressure
in chart
2
.
Check in the firing rate graph of the burner (Fig. 4), if the working
point defined by the values above is within the range limits.
If not, higher burner size is needed.
Note
Charts are based only on altitude variation (reference temperature
= 68°F , 20°C). To get the combined correction in case of different
air temperature, a compensation of
1000 ft each 20°F (305 m each
11°C)
is applicable (100 ft = 2°F).
Example
Rated capacity = 3000 MBtu/hr - Rated air pressure = 1.5”w.c.
Real altitude = 5000 ft - Real temperature = 108°F
= 108°F - 68°F (reference temp.) = 40°F (equivalent 2000 ft vari-
ation)
40 : 2 = 20 x 100 = 2000 ft
Proceeding as descripted above and considering a “virtual altitude”
of (5000 + 2000) ft
- 3000 MBtu/hr at 7000 ft, the corrected capacity is 3847 MBtu/hr
- 1.5” WC at 7000 ft, the corrected burner air pressure is 1.92
Reference conditions (Charts 1-2):
–
Ambient temperature 68 °F (20 °C)
–
Barometric pressure 394” WC (1000 mbar)
–
Altitude 328 ft a.s.l. (100 m a.s.l.).
Example
Output 2579 Mbtu/hr - diameter 24 inch - length 6.6 ft.
WARNING
The firing rate was obtained considering a room
temperature of 68 °F and an atmospheric pressure
of 394 “WC (approx. 0 ft above sea level), with the
combustion head adjusted.
WARNING
In order to utilize also area B (RS 120/E LN), it is
necessary to perform the calibration of the combus-
tion head as explaned in Fig. 19, page 21.
Pr
essure
in combustion
chamber
-
mb
a
r
Fig. 4
D2793
Pr
es
sur
e in
com
bu
sti
on
chamber
-
mb
a
r
A
A
RS 68/E LN
RS 120/E LN
B
Fig. 5
Length of combustion cha
m
ber -
ft
D2919
Fig. 6
8” max
D1079
Содержание RS 120/E LN
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