Note: Descriptions are shown in the official language in which they were submitted.
3':~
FIELD OF THE INVENTION
The present invention relates to a wood-burning
heater which operates satisfactorily in a maple sap evaporator.
BACKGROUND OF TIIE INVENTION
To produce maple syrup the usual practice is to
boil the sap in large vats until the syrup has been reduced by
evaporatLng to the desired consistency.
An ever-increasing number of people sre converting
their oil-burning systems to wood-burning due to the high cost of
energy, but very little technical advance seems to have been made
in this art. With the conventional wood-burning aystem, it is
hard to get a uniform flow of heat all along the vats and with
the use of a flat grille separating the fire pot and ash pit.
A lot of clogging occurs due to the accumulation of ashes, thus
restricting the flow of air in the fire pot.
OBJECTS OF THE INVENTION
.... .. _ _
It is the general object of the present invention
to use new technology to update the old design of the wood-burning
system in a maple sap evaporator.
It is a more specific object of the present invention
to provide a wood burner which produces more heat for the same
quantity of fuel by the provision of a fan forcing the air in the
combustion room to provide a greater quantity of oxygen in the
system, thus allowing a better control of the combustion and also
permitting a better distribution of the heat along the vatY sur~ace.
Another object is to provide a heat source that
will need the minimum oi maintenance, a special grille having
been designed to prevent the clogging of the air passages due to
the accumulation of ashes; the better circulation of the air due
to the new grille also improves the combustion and so the effi-
ciency of the burner.
BRIEF DESCRIPTION OF THE DRAWINGS
The -invention will be further described, by way
of example, with reference to the accompanyLng drawings, in which
- 2 -
735;~
Figure 1 i8 a side elevation, partlally in section, of the
complete burner assembly 8howing i~s ingtalla~ion under a maple sap
evaporator:
Figure 2 is a cross-sectional vlew on line 2-2 of Figure 1.
Figure 3 i9 a fragmentary view o Figure 2 showing the
construction of the grilles on an enlarged scale; and
Figure 4 i9 a perspective view of the burner assembly complete
with the air blower.
DETAILED DESCRIPTION OF THE INVENTION
Rbferring to the drawings, ~igure 1 illustrates the invention
applied to a conventional maple sap evaporator comprislng an elongated
pan la holding a number of vats 1 and located~ over a fire box 2, which
may have a length of, say, 20 feet and a flue (not ~ho~n? at the shallow
rear end portion of box 2. Wood logs 3 are stoked for combustion through
an opening in ~he front end portion 2a of fire box 2 closed by a door 4.
The fire box 2 i9 of substantially the ~ame width and length as
the pan la but the front end portion 2a of fire box 2 has a length which
i9 only a fraction of the total length of fire box 2.
Thi8 fire box 2 is dQsigned ~o provide- heat along the entire
length of the vats 1, but in conventional arrangements, uslng wood logs
as fuel, this heat i9 not uniform, resulting in overheating of the vats 1
closest to fire box end portion 20.
~ he heat source al80 comprises an ash pit 6 located under and
substantially co extensive with the fire box end po~tion 2a. An undulated
grille 7 forms the bottom of fire box end portion 2a and separates the
latter from the ash pit 6. The grille 7, the furrows of which are oriented
in the longitudinal axis, is reinforced along each crest by a metal plate
8 fixed at each extremity to the edges of grille 7.
The undulated grille 7 comprises a number of holes 9 to allow the
passage of the air from the ash plt 6 to the ftre box 2 and the passage
of the ashes falling in the ash pit 6. The access to the inside of the ash
pit 6 for cleaning is done by means of a number of cleaning doors 10
located on the same side a~ the fire box doors 4.
- 3 -
73~
The air i9 forced into the a8h pit 6 and fire box 2 by means of
a centrifugal fan 11 powered by an electric motor 12. The alr is entering
the a~h pit 6 through an opening 13a made in an upright wall 6a of ash
pLt 6, said wall 6a extending below and facing the bottom wall 26 of fire
box 2. The air i8 carried from the fan 11 to the ash pit 6 by means of
cluct 13 of rectangular cross-section. The duct 13 comprises a mechanical
shutter 14 to control the alr pressure inslde the flre box 2.
The pressure must be regul~ted 30 i'C is sufficient to provide
a uniform flow of heat on the vats 1 under surface but not too high so it
10 creates a pressure differential inside the burner and throw ashes or smoke
in the room, especialLy when the doors 4 are opened to put wood 3 in the
fire box 2.
The inside walls of the fire box 2 are covered with a refractory
material 15 to assure a better heat insulation to improve the efficiency
and as a security means a8ainst fire.,
11~e ash pit 6 is supported by at least four adju3table legs 16
to assure a perfect fit between the ash pit 6 and the under3ide of fire
box end portion 2a.
This invention is advantageous in that it gives a better combustion
20 of a fuel, such as wood, because of the forced air but does not required to
seal the fire box 2 and the ash pit 6, since the alr pressure 13 not too
high.
Another advantage i8 the undulated grllle 7 that does not
get clogged because of air accumulatlon of ashe3 arld 90 allow0 the air
10 to pass through more éfficiently.
It will be understood that other modlfications withln the scope
of the appended claims may be rnade in the deslgn and arrangement of the parts
without departing from the splrlt of ~he Lnventlon.
