Unical AIREX 25 2S, Руководство по установке и обслуживанию

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10
Technical features and dimensions
S S S
M
F
F
R
P
F
P
P
S
P-S
F
fig. 5
fig. 6
fig. 7
1
2
3
T1
1. Metallic grate
2. Cast iron fire bars
M = C.H. flow
R = C.H. return
P = Primary air
S = Secondary air
F = Flue
The embers are prevented from falling by cylindrical pieces of
refractory steel. The combustion gases, poor in oxygen and
still rich in carbon not yet combined, travel across the embers
and enter the opening in the centre of the main stone.
Inside this pre-combustion chamber, the gases combine with
the pre-heated secondary air coming through the grooves of
the two cast iron fire bars.
The resulting flame will be highly oxygenated and have a light
blue colour. This flame comes out from the oval opening and
invades the combustion chamber.
Due to the high temperatures the refractory burner will become
a bright red colour.
COMBUSTION CHAMBER (5)
The combustion is optimised by increasing the flame
temperature and producing a strong turbulence in the bottom
chamber.
For this reason the flame, in addition to not to touching cold
walls irrigated by the water, rebounds and is divided on a
semicircular cradle which rests on the lower exchange surfaces
(baffles), which, as well delimiting the smoke passages, also
has the task of collecting the ashes and possible embers.
The flames, after having bounced off the walls of the bottom
area and the refractory ones, direct themselves with a whirling
motion towards the front part of the combustion chamber and
enter the flue ducts. The combustion will be complete and clean
and the dominant colour will be that of the ashes: white.
THERMOSTATIC VALVE (9)
As well known, wood normally has a high moisture content
when compared with other types of fuels. The first operation
which occurs inside the fire box is therefore the drying phase.
The high moisture content can then cause condensation
phenomena within the boiler and also in the chimney.
To limit the inconvenience in the boiler it is necessary to
maintain high working temperatures.
For this reason the boiler is equipped with a patented
ther mostatic system (fig. 6) which per mits the boiler
temperature to be kept constantly high and in particular, in the
fire box, where
the condensation phenomena is more likely to occur.
In order to reduce the consequences of condensate formation
(formation of layers of tar, corrosion, etc.) it is advantageous
to dimension, time by time, the wood load to the actual needs,
so as to prevent long stop overs with the wood storage
completely full of humid wood.
Nevertheless all these expedients do not impede the formation
of condensate in the chimney. Therefore we suggest, when
building the chimney, to use air-tight components, to avoid the
condensate damaging the building structure.