EP2853812A1

EP2853812A1 - Improved brazier in particular for pellet stoves

Info

Publication number: EP2853812A1
Application number: EP14184771.5A
Authority: EP
Inventors: Claudio Mezzalira; Giacomo Zanette; Fabio Cadel; Roberto Dassie
Original assignee: MCZ Group SpA
Current assignee: MCZ Group SpA
Priority date: 2013-09-25
Filing date: 2014-09-15
Publication date: 2015-04-01
Also published as: ITPN20130030U1

Abstract

The present invention is relative to an improved brazier (10) to be housed in a combustion chamber (2) of a stove for burning solid fuel in particle or granular form. Said brazier (10) consists of a collecting receptacle for containing the fuel, comprising a bottom wall (11) provided with a plurality of holes (12) for the passage of combustion air, and of one or more side walls. In particular, the brazier (10) comprises at least one cavity (15) provided on a wall (13) of said one or more side walls and configured so as put into fluid communication the area above said brazier (10) and the core of the fuel held in it to form a further combustion air inflow.

Description

The present invention refers to an improved brazier, in particular for stoves fed with solid fuels in particle form, such as for example pellets, that is, granules of pressed wood residues; if necessary, a brazier according to the present invention can also be used in stoves burning solid fuels in granular form, such as for example the so-called "olive-pomace stones".
As is shown in the attached figure 1, a pellet stove 1 is generally made up of a hollow shell defining a combustion chamber 2, inside of which is housed a brazier 10; the fuel in pellet form is preloaded into a storage hopper (not shown), from which it is collected, for example by a screw feeder 3, and laid gradually in the brazier 10 through a discharge conduit 4.
Said brazier 10 is normally in the form of a receptacle, preferably made of cast iron and essentially of box-like or cylindrical shape, suitable to receive the fuel, provided with a bottom wall having a plurality of holes through which the combustion air is allowed to pass.
In particular, thanks to the vacuum created by a smoke exhaust fan 20, fresh air is drawn in from outside and conveyed through an access conduit 16 to the combustion chamber 2, where, passing through the plurality of holes on the bottom of the brazier, feeds the combustion; at the same time, the exhaust gases are drawn out and expelled through an outflow conduit 17.
The brazier 10 is associable to said access conduit 16 through an ignition aperture 14 formed on a lateral wall of the brazier, preferably near the bottom wall of the same. Inside said access conduit 16 are advantageously provided air heating means 18, such as for example an electric heating element called in the technical terminology "glow plug", arranged advantageously in the proximity of the brazier 10, which in the stove ignition phase generates the heat necessary to ignite the pellets.
A tray drawer accessible from outside is provided to receive the ash and solid combustion residues that fall from the overlying brazier 10 through the holes on the bottom wall.
A problem that is occasionally found with the stoves described above lies in the fact that, if the brazier is not cleaned regularly, the ash generated in successive combustions tends to accumulate on the bottom of the brazier and to obstruct the holes provided on it, thus preventing the passage of the combustion air and compromising the optimal operation of the stove.
This problem could become critical, particularly in the step of ignition of the stove 1; in fact, due to the occlusion of the holes, the combustion air drawn in from outside cannot penetrate into the brazier, thus effectively preventing the immediate ignition of the fuel. In the meantime, however, the pellets are continually collected and laid inside the brazier 10 until they completely obstruct the ignition aperture 14 opposite which there is the outlet of the access conduit 16 that houses the electrical heating element 18, or "glow plug".
Due to the very high temperatures reached by the fuel in the brazier in proximity of the "glow plug", and in the lack or absence of the combustion air necessary for ignition, a flameless combustion is generated (embers), which however produces combustion gases.
This situation may entail dangerous build-ups of gases in the combustion chamber 2, which, if ignited, could become explosive.
The objective of the subject matter of the present invention is to find a solution to the above problem by devising a brazier for solid fuel stoves, in particular for pellet stoves, that guarantees the passage of combustion air through it even in critical conditions, that is, in the stove priming phase and with the brazier having the bottom holes occluded, thus allowing the safe ignition of the fuel and the correct operation of the stove.
In the scope of the above objective, one purpose of the present invention is to devise a brazier, in particular for pellet stoves, that is simple and economic to manufacture with the usual well-known plants, machines and equipment.
Another purpose of the present invention is to provide a brazier, in particular for pellet stoves, that can be easily installed, even in stoves already present on the market or already in use, without having to modify their structure.
The above objective and purposes, and others that will become more evident hereafter, are achieved by a brazier as defined in claim 1; further features are defined in the subsequent dependent claims.
Advantages and characteristics of the invention will become evident from the description which follows, given by way of non-limiting example, with reference to the enclosed figures, in which:

figure 1 is a schematic view in cross section of a pellet stove as already described;
figure 2 is a perspective view from above of a brazier for a pellet stove according to the present invention;
figure 3 is a front view in cross section of a brazier for a pellet stove according to the present invention.

The present invention refers substantially to an improved brazier 10, suitable to be used in a stove for solid fuel in granular form, such as for example a pellet stove 1 as previously described with reference to figure 1.
As shown in figures 2 and 3, said brazier 10 is substantially formed from a collecting receptacle, suitable for containing pellets, having for example a cylindrical or box-like shape, defined by one or more side walls and provided with a bottom wall 11.
The bottom wall 11 of said brazier 10 has a plurality of holes 12 that, as previously explained, allow the passage of the combustion air into the brazier to maintain the combustion.
One of said one or more side walls, indicated in the figures with reference numeral 13, is provided, preferably in a portion near the bottom wall 11, with a through ignition aperture 14, through which the brazier 10 is associable to said first conduit 16 in correspondence of the heating element 18, so as to allow, in the ignition phase, the inflow of heated combustion air for igniting the fuel.
In fact, the heated combustion air, flowing through said ignition aperture 14, penetrates directly into the core of the fuel loaded into the brazier 10 and, working in synergy with the air passing through the plurality of holes 12, makes it possible to ignite the pellets.
To solve the problem of failure to ignite the fuel that could occur in critical conditions, that is, when the holes 12 are partially or completely occluded by the piled up ash and solid residues from previous combustions and therefore do not allow a sufficient passage of combustion air, said brazier 10 is advantageously supplied with at least one cavity 15, provided on at least one of said one or more side walls and configured so as to put into fluid communication the area above the brazier 10 and the core of the fuel contained in it, thus guaranteeing a further inflow of combustion air.
Advantageously, said at least one cavity 15 is formed on the wall 13 provided with said ignition aperture 14, so as to allow a sufficient supply of combustion air to prime the ignition, in particular near the electrical heating element 18 where, as already mentioned, the embers are more likely to form during the stove ignition phase.
Preferably, as shown in figures 2 and 3, the brazier 10 includes a pair of cavities 15, formed by corresponding superficial grooves that are essentially parallel to each other on said wall 13. Said grooves 15 extend in particular on the surface of said wall 13 facing the inside of the brazier 10, preferably in vertical direction, from the upper edge 13A of the wall to said ignition aperture 14.
Advantageously, said grooves 15 have a width L that is smaller than the typical diameter of the pellet (generally included between about 6 and 8 mm), and therefore, when the fuel is laid inside the brazier 10, they are not obstructed; they remain substantially free and thus form access channels for combustion air to flow toward the core of the fuel, and in particular in the zone where the embers are likely to form.
If necessary, said cavities 15 can be closed, forming substantially conduits, welded on the inside surface of said wall 13 of the brazier 10 or passing within it; in this case, the width of said cavities 15 can clearly be larger, since they cannot be clogged by the pellet laid in the brazier 10.
In conclusion, from the above it is clear how the present invention achieves the initially foreseen purposes and advantages; in effect, an improved brazier 10 has been devised for solid fuel stoves, in particular for pellet stoves, capable of guaranteeing the flow of combustion air to enter within it even in critical conditions, always making it possible to prime the flame in the ignition phase and to enable the proper operation of the stove, with advantages in terms of safety and economy.
Moreover, the brazier 10 of the present invention is extremely simple from the point of view of its construction, as it can be produced by applying a simple modification to a brazier of the prior art. For the same reason, the brazier 10 can be installed if necessary in a stove already in use, by replacing the one previously mounted in the same stove.
Naturally, the present invention is amenable to numerous applications, modifications or variants without thereby departing from the scope of patent protection, as defined in the enclosed claims.
Moreover, the materials and equipment used to implement the present invention, as well as the shapes and dimensions of the individual component, can be the most suitable for the specific requirements.

Claims

Brazier (10) to be housed in a combustion chamber (2) of a stove for burning solid fuel in particle or granular form, said brazier (10) being formed from a collecting receptacle for containing said fuel comprising a bottom wall (11) provided with a plurality of holes (12) for the passage of combustion air, and one or more side walls, characterized in that it comprises at least one cavity (15) provided on a wall (13) of said one or more side walls and configured so as to put into fluid communication the area above the brazier (10) and the core of the fuel contained in it to guarantee a further inflow of combustion air.
Brazier (10) according to claim 1, wherein said wall (13) also comprises an ignition aperture (14) through which said brazier (10) is associable to an access conduit (16) of heated combustion air for igniting the fuel.
Brazier (10) according to claim 2, wherein said at least one cavity (15) extends to the surface turned toward the inside of the brazier (10) of said wall (13), extending from an upper edge (13A) of the same to said ignition aperture (14).
Brazier (10) according to any one of the previous claims, wherein said at least one cavity (15) is formed by a pair of parallel grooves.
Brazier (10) according to any one of the previous claims, wherein said at least one cavity (15) has a width (L) that is smaller than the diameter of the fuel particles.
Brazier (10) according to any one of the previous claims from 1 to 3, in which said at least one cavity (15) comprises a pair of parallel conduits welded on the internal surface of said wall (13) or passing through the inside of said wall (13).
Stove for solid fuel in particle or granular form (1) comprising a brazier (10) according to any of the claims from 1 to 6.