Choice Of Nozzles For 1St And 2Nd Stage; Nozzle Assembly - Riello RL 190 Two-Stage Operation

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.
As a rule the two nozzles have equal deliveries but the 1st stage
nozzle may have a delivery less than 50% of the total delivery
when a reduction of the counter-pressure peak is desired at the
moment of starting (the burner allows good combustion rates
also with a 40 - 100 % ratio between the 1st and 2nd stage).
Example
Boiler output = 1630 kW - efficiency 90 %
Output required by the burner =
1630 : 0,9 = 1812 kW;
1812 : 2 = 906 kW per nozzle;
therefore, two equal, 60°, 12 bar nozzles are required:
1° = 18 GPH - 2° = 18 GPH,
or the following two different nozzles:
1° = 16 GPH - 2° = 20 GPH.
5.7

Nozzle assembly

At this stage of installation the burner is still disassembled from
the blast tube; it is therefore possible to fit the nozzle with the box
spanner 1) (Fig. 8) (16 mm), after having removed the plastic
plugs 2) (Fig. 8), fitting the spanner through the central hole in the
flame stability disk. Do not use any sealing products such as gas-
kets, sealing compound, or tape. Be careful to avoid damaging
the nozzle sealing seat. The nozzles must be screwed into place
tightly but not to the maximum torque value provided by the
wrench.
The nozzle for the 1st stage of operation is the one lying beneath
the firing electrodes (Fig. 9)
Make sure that the electrodes are positioned as shown in (Fig. 9)
Finally refit the burner 3) (Fig. 10) to the slide bars 2) and slide it
up to the flange 5), keeping it slightly raised to prevent the
flame stability disk from pressing against the blast tube.
Tighten the screws 1) on the slide bars 2) and screws 4) fixing the
burner to the flange.
If it proves necessary to change a nozzle with the burner already
fitted to the boiler, proceed as outlined below:
– Retract the burner on its slide bars as shown in (Fig. 7
pag. 10).
– Remove the nuts 1) (Fig. 11) and the disk 2).
– Use spanner 3) (Fig. 11) to change the nozzles.
Installation
GPH
10 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
light oil: density 0.84 kg/dm
(1)
perature 10 °C
11 GB
kg/h (1)
12 bar 14 bar
19.2 21.2 23.1
21.1 23.3 25.4
23.1 25.5 27.7
25.0
27.6 30.0
26.9 29.7 32.3
28.8 31.8 34.6
30.8 33.9 36.9
31.9 35.2 38.3
32.7 36.1 39.2
34.6 38.2 41.5
36.5 40.3 43.8
38.4 42.4 46.1
40.4 44.6 48.4
42.3 46.7 50.7
46.1 50.9 55.3
47.3 52.2 56.7
50.0 55.1 59.9
53.1 58.5 63.3
53.8 59.4 64.5
57.7 63.6 69.2
58.8 64.9 70.5
61.5 67.9 73.8
65.4 72.1 78.4
67.3 74.2 80.7
69.2 76.4 83.0
73.0 80.6 87.6
75 82.7 89.9
76.9 84.8 92.2
82.7 91.2 99.1
84.6 93.3 101.4
3
- viscosity 4.2 cSt/20 °C - tem-
D691
kW
12 bar
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
Tab. B
Fig. 8
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