Ariterm 35+, Operating Instructions Manual

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9
OPERATING PRINCIPLE
The Ariterm 35+ boiler is meant for use at full power, then complete gasification of the wood
will take place and the combustion will be clean. The amount of energy available from the boiler
to the accumulator will be optimal and the need for cleaning small. The boiler will also last lon-
ger with proper burning.
Wood gasification
This takes place at the grate at the bottom of the storage chamber. The primary air needed for
gasification rises through the plate-controlled damper to the carbonisation section, where the
wood gasifies. The refill hatch is inclined at an angle, so loading the wood into the storage cham-
ber is easy and safe. Gas-powered dampers make hatch opening easy. The storage chamber ex-
pands as it goes further down, so is wide enough to ensure that wood does not get stuck against
the chamber walls. The chamber has a volume of 120 litres, which will accommodate about 37
kg of dry firewood. Burning time is three hours without having to add more wood, and the tem-
perature in a 2000-litre accumulator will rise by about 50°C, if no heat is being used at the same
time.
Afterburning of gases
This takes place in a round ceramic chamber, into which pre-heated secondary is introduced.
Adjustment of the secondary air is done using the lower damper. The key factor in clean com-
bustion is the complete mixing of combustion gases and pre-heated combustion air at a high
temperature. In the afterburning chamber, the temperature rises to almost 1000°C, at which
point different gases emitted from the wood ignite and are completely burned. The afterburner
chamber is a vertical cylinder and is made of ceramic parts.
Heat recovery
This takes place in the carefully dimensioned convection section, in which heat is efficiently
transferred from the super-heated combustion gases to the boiler water. The convection section
is vertical, so that fly-ash does not accumulate on its inner surfaces. Regular brushing of the con-
vection section keeps the boiler efficient.