Riello RL Series - 5.6 Choice of nozzles for 1 st and 2 nd stage

13
20111051
GB
Installation
5.6 Choice of nozzles for 1st and 2nd stage
Both nozzles must be chosen from among those listed in table
(Tab. B).
The first nozzle determines the delivery of the burner in the 1st
stage.
The second nozzle works together with the 1st nozzle to deter-
mine the delivery of the burner in the 2nd stage.
The deliveries of the 1st and 2nd stages must be contained within
the value range indicated on pag. 6.
Use nozzles with a 60° spray angle at the recommended pres-
sure of 12 bar.
The two nozzles usually have equal deliveries, but the 1st stage
nozzle may have the following specifications if required:
➤ a delivery less than 50% of the total delivery whenever the
back-pressure peak must be reduced at the moment of fir-
ing: the burner allows good combustion values also with a
ratio 40 - 100 % between the 1st and 2nd stage;
➤ a delivery higher than 50% of the total delivery whenever
the combustion during the 1st stage must be improved.
Tab. B
(1)
light oil: density 0.84 kg/dm
3
- viscosity 4.2 cSt/20 °C - tem-
perature 10 °C
Example with the RL 70 model:
Boiler output = 635 kW - efficiency 90 %
Output required by the burner =
635 : 0,9 = 705 kW
705 : 2 = 352 kW per nozzle;
therefore, two equal, 60°, 12 bar nozzles are required:
1° = 7,0 GPH - 2° = 7,0 GPH,
or the following two different nozzles:
1° = 6,0 GPH - 2° = 8,0 GPH,
or:
1° = 8,0 GPH - 2° = 6,0 GPH,
GPH
kg/h (1)
kW
12 bar
10 bar 12 bar 14 bar
5.00
5.50
6.00
6.50
7.00
7.50
8.00
8.30
8.50
9.00
9.50
10.0
10.5
11.0
12.0
12.3
13.0
13.8
14.0
15.0
15.3
16.0
17.0
17.5
18.0
19.0
19.5
20.0
21.5
22.0
19.2
21.1
23.1
25.0
26.9
28.8
30.8
31.9
32.7
34.6
36.5
38.4
40.4
42.3
46.1
47.3
50.0
53.1
53.8
57.7
58.8
61.5
65.4
67.3
69.2
73.0
75
76.9
82.7
84.6
21.2
23.3
25.5
27.6
29.7
31.8
33.9
35.2
36.1
38.2
40.3
42.4
44.6
46.7
50.9
52.2
55.1
58.5
59.4
63.6
64.9
67.9
72.1
74.2
76.4
80.6
82.7
84.8
91.2
93.3
23.1
25.4
27.7
30.0
32.3
34.6
36.9
38.3
39.2
41.5
43.8
46.1
48.4
50.7
55.3
56.7
59.9
63.3
64.5
69.2
70.5
73.8
78.4
80.7
83.0
87.6
89.9
92.2
99.1
101.4
251.4
276.3
302.4
327.3
352.3
377.2
402.1
417.5
428.2
453.1
478.0
502.9
529.0
553.9
603.7
619.1
653.5
693.8
704.5
754.3
769.7
805.3
855.1
880.0
906.1
956.0
980.9
1005.8
1081.7
1106.6