1
2
3
4
5
6
7
8
0
10
20
30
40
Portata m
3
/h
∆
p mbar
6
Fig. 2
3.4
PRESSURE DROPS (fig. 2)
3.5
STRUCTURE OF THE BOILER
The
PIROEMME
boiler operates with
wood based on the traditional method
of reverse-flame gasification of wood.
Br oadl y speaking, t he boiler is
structured as illustrated below.
3.5.1
Drying and gasification
area (fig. 3)
Wood distillation or gasification takes
part in the lower part of this area
(wood storage area).
Gasification must be as regular as
possible over time and its speed
depends on the amount of fuel and the
size of the drying area. In general, it is
preferable to have large pieces of dry
wood and small pieces of damp wood.
The amount of primary air, which is
proportional to the output, is adjusted
with a control system.
3.5.2 Refractory burner (fig. 3)
The r efr act or y bur ner has a
rectangular opening in the middle
where the flame passes through.
The burner has a rectangular groove
where there is a cast iron deflector
used t o hold t he ember s
(an
additional backup def lect or is
supplied as standard)
.
Combustion gases, with a low oxygen
content and still rich of non-combined
carbon, go through the embers and
pass t hr ough t he opening of t he
refractory burner.
Inside the burner, the gases mix with
the preheated secondar y air that
enters through the special groves of
the plate. This will generate a light blue
highly oxygenated flame, which comes
out from the lower opening and enters
inside the combustion chamber.
Given the temperatures involved, the
refractory material will become bright
red.
3.5.3 Combustion chamber (fig. 3)
After transferring the energy to the
wat er, the combus tion gases are
collected at the rear of the boiler.
In the flue-gas chamber there is a two-
speed fan with an horizont al axis
consisting of an electric motor and an
impeller. The fan is easy to maintain,
as it is secured with nuts.
3.5.4 Adjusting the
combustion air (fig. 3)
At the front of the boiler, between the
top and bottom door, there are the
combustion air outlets.
The air entering inside the boiler is
divided into primary and secondary air.
The primary air is directed to the
wood storage area and by combining
with the distilled gas, it creates the
combus tible mix t hat bur ns as it
passes through the refractory burner.
Flow rate m
3
/h
