Patent Description:
Heating apparatuses are known, commonly called stoves, which use biomass in an inconsistent form for fuel, for example formed by chips, pellets or suchlike, in which combustion occurs thanks to the presence of a comburent, usually consisting of the oxygen contained in the ambient air, which is supplied as primary and secondary air. The primary air is made to enter a brazier to fuel the combustion of the biomass after the latter has first been ignited.

When operating normally, pyrolysis occurs during combustion, that is, the physical and chemical decomposition process of the combustible biomass, caused by it being heated to temperatures between about <NUM> and about <NUM>.

As is known, pyrolysis decomposes biomass into two parts: one gaseous and one solid. The gaseous part consists of a flammable mixture of gases, such as mainly carbon monoxide, hydrogen and methane, and a condensable compound, known to persons of skill in the art by the acronym TAR, while the solid part substantially consists of coal, known also by the term CHAR.

The mixture of gases derived from pyrolysis, which in this field is called "syngas", is ignited by ignition, and with the introduction of secondary air completes the combustion of the biomass, generating heat and a flame.

Known stoves, which are based on the pyrolysis process, have a brazier in which the biomass can be loaded, which can then be ignited. Primary air can be introduced into the brazier to create a so-called "flame cap" above the biomass.

When the stove is working, the heat of the combustion descends into the brazier in proximity to the still non-combusted biomass and causes the pyrolysis thereof. Then, to complete the combustion, secondary air is introduced into the brazier which ignites the combustible gases resulting from pyrolysis.

However, these known stoves have a series of disadvantages such as, for example, poor performance, poor versatility of use, difficult management of the power and speed of production of the combustible gases and discontinuous operation.

In fact, the combustion process occurs until the loaded biomass is completely consumed by the pyrolysis process. When this process ends, because the biomass is finished, it is necessary to reload more biomass into the brazier and then restart the process by means of a new ignition. It is therefore quite clear that these operations require the intervention of an operator.

In addition, the introduction into the brazier of ambient air, having an oxygen component of approximately <NUM>% by weight, contributes to a high production of polluting gases. In fact, biomass also includes nitrogen, generally bound with the carbon and hydrogen atoms present in it, and which, as is known, binds with the oxygen of the ambient air introduced into the brazier, producing nitrogen oxides which are very polluting.

Document <CIT>, on which the two-part-form of claim <NUM> is based, describes a biomass stove having a brazier disposed below a combustion chamber and having an upper loading aperture through which the biomass is inserted. The brazier also comprises a plurality of lower apertures connected to the combustion chamber by means of a recirculation gap. In this way the smoke generated in the combustion chamber is taken from it and introduced into the brazier through the lower apertures to trigger the pyrolysis of the biomass. Moreover, the brazier also comprises a plurality of upper apertures communicating with the external environment, and which allow to introduce air directly into the brazier so as to contribute to the combustion of the biomass and combustible gases produced by pyrolysis. This promotes the formation of nitrogen oxides which contribute to increasing the polluting emissions produced by the stove.

There is therefore a need to provide a new and original heating apparatus that can overcome at least one, better all, the disadvantages of the state of the art.

One purpose of the present invention is to provide a heating apparatus that produces reduced pollutant emissions into the environment.

The dependent claims describe other characteristics of the present invention.

In accordance with the above purposes, a heating apparatus which overcomes the limits of the state of the art and eliminates the defects present therein, comprises both a brazier suitable to thermochemically decompose a biomass and produce at least one combustible gas and which in turn comprises a first entry aperture to receive the biomass which functions as fuel and a second aperture to receive a first comburent, and also a combustion chamber which is autonomous with respect to the brazier, is delimited by a plurality of walls and is suitable to develop heat by means of a flame.

According to the invention, the apparatus comprises conveyor means interposed between the brazier and the combustion chamber to convey the at least one combustible gas to the combustion chamber.

According to the present invention, on at least one first wall of the plurality of walls, one or more recirculation apertures are made, each of which is connected by means of recirculation means to the second aperture of the brazier.

According to the present invention, the heating apparatus also comprises a containing body configured to define, together with the first wall, a containing compartment in which the recirculation means are disposed.

According to the present invention, the containing body is also configured to receive a second comburent from the external environment, in such a way that it is heated by the recirculation means, and to direct it into the combustion chamber.

According to another aspect of the present invention, at least one feed aperture communicating with the external environment is made in the containing body, and the combustion chamber also comprises an entry aperture communicating with the containing compartment.

According to another aspect of the present invention, the recirculation means comprise at least one recirculation conduit which is substantially parallel to the first wall and is detached from the latter, and the containing body also comprises a dividing wall which divides the containing compartment into a first part containing the at least one recirculation conduit, and into a second part which substantially laps at least the first wall.

According to another aspect of the present invention, the upper part of the dividing wall is substantially disposed in correspondence with the zone in which the at least one recirculation conduit is connected to the at least one recirculation aperture. Furthermore, the first part and the second part are in communication with each other in correspondence with the upper part of the dividing wall.

According to another aspect of the present invention, the recirculation means comprise a plurality of recirculation conduits substantially parallel to, and detached from, each other, the first wall comprises a corresponding plurality of recirculation apertures each communicating with a respective one of the recirculation conduits.

According to another aspect of the present invention, the heating apparatus also comprises a first fan fluidically connected downstream of the recirculation means and upstream of the second aperture of the brazier.

According to another aspect of the present invention, the combustion chamber also comprises at least one evacuation aperture and the heating apparatus also comprises a second fan connected downstream of the at least one evacuation aperture and upstream of the external environment in order to convey at least a part of the fumes produced by the flame into the combustion chamber.

According to another aspect of the present invention, the heating apparatus also comprises a control unit and a sensor which is disposed downstream of the combustion chamber and is configured to detect the quantity of oxygen present in the fumes and to transmit a signal proportional to the quantity of oxygen detected in the fumes to the control unit, in order to allow the control unit to regulate at least the flow rate generated by the second fan as a function of the signal.

According to another aspect of the present invention, the brazier also comprises an exit aperture which is in fluidic communication with the entry aperture of the combustion chamber by means of conveyor means.

According to another aspect of the present invention, the entry apertures of the brazier are disposed at a higher level than that on which the exit aperture is located.

According to another aspect of the present invention, a heating method using a heating apparatus according to the invention comprises the following steps:.

According to another aspect of the present invention, the heating method also comprises the following steps:.

We must clarify that in the present description and in the claims the term vertical, with its declinations, has the sole function of better illustrating the present invention with reference to the drawings and must not be in any way used to limit the scope of the present invention itself, or the field of protection defined by the attached claims. For example, by the term vertical we mean an axis or a plane that can be either perpendicular to the line of the horizon, or inclined, even by several degrees, for example up to <NUM>°, with respect to the latter.

Furthermore, the people of skill in the art will recognize that certain sizes or characteristics in the drawings may have been enlarged, deformed, or shown in an unconventional or non-proportional way in order to provide a version of the present invention that is easier to understand. When sizes and/or values are specified in the following description, the sizes and/or values are provided for illustrative purposes only and must not be construed as limiting the scope of protection of the present invention, unless such sizes and/or values are present in the attached claims.

With reference to <FIG>, a heating apparatus <NUM> according to the present invention is of the pyrolysis type and, in accordance with a first embodiment, comprises thermochemical decomposition means M1 configured to receive a biomass C which functions as fuel and a first comburent F1, as will be explained below.

The thermochemical decomposition means M1 are suitable to thermally decompose the biomass C and produce, by means of pyrolysis, combustible gases S, for example consisting mainly of methane, hydrogen, carbon monoxide.

The heating apparatus <NUM> also comprises a combustion chamber <NUM> configured to receive both a second comburent A, different from the first comburent F1, and also the combustible gases S. The combustion chamber <NUM> is suitable to develop heat by means of a flame, fed by the combustible gases S and which produces fumes F, as will be explained below.

Furthermore, the heating apparatus <NUM>, in accordance with the present invention, comprises both conveyor means M2 interposed between the thermochemical decomposition means M1 and the combustion chamber <NUM> to convey the combustible gases S toward the latter, and also recirculation means M3 to convey at least a first part F1 of the fumes F, which constitutes the first comburent, from the combustion chamber <NUM> to the thermochemical decomposition means M1.

Furthermore, the heating apparatus <NUM> comprises heat exchange means M4, associated with the recirculation means M3 and configured to heat the second comburent A, using the heat contained in the first comburent F1 before the second comburent A reaches the combustion chamber.

Hereafter, with reference to <FIG> and from <NUM> to <NUM>, the first embodiment of the heating apparatus <NUM> is described in more detail.

The thermochemical decomposition means M1 comprise a brazier <NUM> substantially closed with respect to the external environment and delimited by four lateral walls <NUM> and one upper wall <NUM>. Furthermore, the brazier <NUM> is delimited at the bottom by a metal plate <NUM> provided with at least one exit aperture <NUM>.

The exit aperture <NUM> of the brazier <NUM> is also configured to allow the combustible gases S to exit and the burnt and/or thermochemically decomposed biomass C to be discharged from the brazier <NUM>.

The metal plate <NUM> can be selectively removable or openable, in any known way, to allow access to the brazier <NUM> from below, for example to carry out maintenance or cleaning thereof.

Furthermore, the brazier <NUM> has an entry aperture <NUM> for the biomass C to be introduced, comprising, for example, inconsistent wooden material such as chips, pellets or suchlike, and an entry aperture <NUM> from which the first comburent F1, which is of the aeriform type, can enter.

It should also be noted that the brazier <NUM> does not have any apertures that allow the comburent air to enter directly from the external environment.

The entry apertures <NUM> and <NUM> of the brazier <NUM> are preferably disposed in the upper part of the latter, that is, at a higher level than the one at which the exit aperture <NUM> is located. This configuration allows to introduce the biomass C and the first comburent F1 from the top downward.

It should be noted that the reciprocal position of the first aperture <NUM> and of the second aperture <NUM> may vary compared to that shown in the drawings, so that, for example, one or both can be disposed laterally, or one at a different level from the other.

In an alternative embodiment, not shown in the drawings, the first aperture <NUM> of the brazier <NUM> can be disposed substantially level with the lower part thereof. In this configuration, the biomass C can be introduced into the brazier <NUM> from the bottom upward, or, alternatively, laterally, that is, in a substantially horizontal way. For example, the first aperture <NUM> can be disposed substantially level with the metal plate <NUM>, in order to introduce the biomass C directly above the latter.

Furthermore, inside the brazier <NUM> there is an ignition device <NUM>, configured to selectively trigger the combustion of the biomass C, for example when the heating apparatus <NUM> is switched on.

In the embodiment shown here, the ignition device <NUM> comprises an electrical resistance disposed in a lower zone of a lateral wall <NUM>, that is, close to the metal plate <NUM>, for example in the same lateral wall <NUM> in which the first entry aperture <NUM> is made.

The ignition device <NUM> can be sized so as to come into contact, during use, with the biomass C present in the brazier <NUM>. Alternatively, the ignition device <NUM> can be configured to ignite the biomass C indirectly, that is, by heating the air in contact with the latter.

The combustion chamber <NUM> is substantially closed and is in fluidic communication with the brazier <NUM> by means of a conveyor compartment <NUM>, which is preferably hermetically sealed. In particular, the conveyor compartment <NUM> is interposed between the lower part of the brazier <NUM> and the lower part of the combustion chamber <NUM>. Alternatively, the conveyor compartment <NUM> can be replaced by one or more conduits.

We must clarify that the exit aperture <NUM> of the brazier <NUM> flows directly into the conveyor means M2. In particular, in the example provided here, the exit aperture <NUM> of the brazier <NUM> flows directly into the conveyor compartment <NUM>, which defines the conveyor means M2.

We must also clarify that, in accordance with the present invention, the brazier <NUM> and the combustion chamber <NUM> are autonomous, separated from each other and connected in a fluidic way by means of the conveyor compartment <NUM>.

According to the invention, the combustion chamber <NUM> is fluidically connected with the comburent entry aperture <NUM> of the brazier <NUM>.

In particular, in the embodiment described here, the combustion chamber <NUM> is delimited by two lateral walls <NUM>, by one upper wall <NUM>, by one front wall <NUM>, for example able to be opened, which functions as closing door, by one rear wall <NUM> and by one lower wall <NUM>.

One or more recirculation apertures <NUM> are made on an upper part of the rear wall <NUM>, each communicating with an upper end of a respective recirculation conduit <NUM>, which is outside the combustion chamber <NUM> and has a lower end which, by means of a manifold <NUM>, is connected to the intake of a first fan <NUM>, the delivery of which is fluidically connected to the second entry aperture <NUM> of the brazier <NUM>.

In addition or alternatively, the recirculation apertures <NUM> can be made in other walls of the combustion chamber <NUM>.

Preferably, the recirculation conduits <NUM> are substantially parallel to each other and to the rear wall <NUM>, and also detached from each other and from the rear wall <NUM>, for example by between <NUM> and <NUM>.

The heating apparatus <NUM> also comprises a containing body <NUM>, substantially box-shaped, on which two feed apertures <NUM> are made, which are in communication with the outside and through which the second comburent A can enter.

The containing body <NUM> is attached on the external surface of the rear wall <NUM> of the combustion chamber <NUM> creating, in cooperation with the latter, a containing compartment V in which the recirculation conduits <NUM> are disposed.

An entry aperture <NUM> is made in the bottom wall <NUM> of the combustion chamber <NUM>, substantially in a central zone thereof, in said entry aperture <NUM> there being positioned a nozzle <NUM> having, in the example given here, a central conduit <NUM> disposed along a longitudinal axis X, substantially vertical, and a series of lateral through holes <NUM>, which substantially lie on a substantially horizontal plane P disposed below the lower wall <NUM>. The lateral holes <NUM> are in communication with the central conduit <NUM>.

We must clarify that the conformation and disposition of the central conduit <NUM> and of the lateral holes <NUM> may differ, even considerably, compared to what is described here and represented in the attached drawings. For example, instead of the lateral holes <NUM>, an aperture or a slot (not shown) of any suitable shape and size can be made.

The central conduit <NUM> is in communication with the conveyor compartment <NUM> and has the function of injecting the combustible gases S into the combustion chamber <NUM>, while the lateral holes <NUM> have the function of conveying the second comburent A, coming from the containing compartment V. In particular, the second part V2 of the containing compartment V surrounds the portion of the nozzle <NUM> on which the lateral holes <NUM> are made, which are configured to receive the second comburent A coming from the second part V2 of the containing compartment V and to promote the mixing of the second comburent A with the combustible gases S in order to promote the combustion of the latter.

The feed apertures <NUM> are disposed below the lower ends of the recirculation conduits <NUM>, that is, substantially level with the lower part of the combustion chamber <NUM>.

Furthermore, a dividing wall, or partition, <NUM> is disposed inside the containing body <NUM>, substantially dividing the containing compartment V into two parts, that is, into a first part V1, in which the recirculation conduits <NUM> are disposed, and into a second part V2, which laps both the rear wall <NUM> and also the lower wall <NUM> of the combustion chamber <NUM>.

The first part V1 and the second part V2 of the containing compartment V are in communication with each other in correspondence with the upper part of the partition <NUM> which, preferably, is disposed in correspondence with the upper ends of the recirculation conduits <NUM>, that is, where the latter are connected to the respective recirculation apertures <NUM>.

Therefore, during use, the second comburent A enters from the feed apertures <NUM>, passes through the first part V1 of the containing compartment V and heats up in contact with the recirculation conduits <NUM>, until it reaches the top of the partition <NUM>. Then, the second comburent A enters the second part V2 of the containing compartment V from above and passes through it all, until it reaches the lateral holes <NUM> of the nozzle <NUM>, lapping the rear wall <NUM> of the combustion chamber <NUM>, heating up further.

It should be noted that, thanks to this conformation, the containing body <NUM>, in cooperation with the recirculation conduits <NUM> and the walls <NUM> and <NUM> of the combustion chamber <NUM>, constitutes a counter-current heat exchanger, which corresponds to the heat exchange means M4 as above.

Furthermore, on each of the lateral walls <NUM> (<FIG>) of the combustion chamber <NUM> there are evacuation apertures <NUM>, to each of which a respective evacuation pipe <NUM> is connected, outside the combustion chamber <NUM> and substantially vertical.

Each evacuation pipe <NUM> is fluidically connected to an evacuation chamber <NUM>, in turn connected to the intake of a second fan <NUM> (<FIG>), the delivery of which communicates with the outside of the apparatus <NUM>.

The heating apparatus <NUM> can optionally also comprise an external containing structure <NUM>, substantially in the shape of a parallelepiped and comprising a second compartment <NUM>, inside of which there are disposed, with ample clearance, both the evacuation pipes <NUM> and also at least a part of the combustion chamber <NUM>, of the conveyor compartment <NUM> and of the evacuation chamber <NUM>.

The external structure <NUM> has, in its lower part, an entry aperture <NUM>, to which a third fan <NUM> is connected in order to selectively introduce ambient air R into the second compartment <NUM>, and in its upper part an exit aperture <NUM> from which the same air R can exit in contact with the evacuation pipes <NUM>.

The heating apparatus <NUM> also comprises an injection device <NUM>, of any type known per se, to introduce the biomass C into the brazier <NUM> in a controlled way, whether intermittently or continuously.

In the example provided here, the injection device <NUM> comprises a container <NUM>, substantially in the shape of a hopper, containing a biomass C load and an associated metering device <NUM>, of a type known per se, having an exit connected to the entry aperture <NUM> of the brazier <NUM> and configured to meter the quantity of biomass C introduced into the brazier <NUM> in a way that is selective and proportional to certain electrical signals, under the control of a control unit <NUM> (<FIG>), as will be described in detail below.

Therefore, the biomass C lies in an autonomous environment with respect to the brazier <NUM>, and it is introduced therein in a selective, automatic and substantially continuous way by the injection device <NUM>.

The metering device <NUM> (<FIG>) is of the type which comprises a rotating element <NUM> provided with radial blades <NUM> and connected to an electric motor <NUM> (<FIG>) controlled by the control unit <NUM>. With each rotation, even partial, of the rotating element <NUM>, a certain quantity of biomass C is introduced into the brazier <NUM>, by means of a connection conduit <NUM>.

It is therefore clear that the quantity of biomass C introduced into the brazier <NUM>, in a given unit of time, is a function of the rotation speed of the rotating element <NUM> (<FIG>).

In other embodiments, not shown in the drawings, the metering device <NUM> can comprise an auger.

The injection device <NUM> allows to introduce the biomass C into the brazier <NUM> in an automatic, controlled and continuous way, so as to allow to adjust the flow rate of biomass C introduced into the brazier <NUM>.

The heating apparatus <NUM> also comprises a sensor <NUM> (<FIG> and <FIG>), also of a type known per se and for example consisting of a lambda probe, which is suitable to detect the quantity of oxygen present in the environment which surrounds it. In the example provided here, the sensor <NUM> is positioned downstream of the combustion chamber <NUM> and in particular inside the evacuation chamber <NUM>.

In other embodiments, the sensor <NUM> can be disposed inside the evacuation pipes <NUM> and/or inside the recirculation conduits <NUM> in order to detect the quantity of oxygen in the fumes F.

The sensor <NUM> is connected to the control unit <NUM> and it is configured to transmit to the latter an electrical signal SP proportional to the quantity of oxygen detected by it.

The control unit <NUM> is configured to also control the first fan <NUM> and the second fan <NUM>, and possibly also the third fan <NUM>.

In addition, the control unit <NUM> is configured to command the operation of the recirculation means <NUM> in order to adjust the flow rate of the first comburent F1, and to command the operation of the injection device <NUM> in order to control the flow rate of the biomass C introduced into the brazier <NUM>.

In particular, the control unit <NUM> can control the rotation speed of the first fan <NUM> and consequently the flow rate of the first comburent F1, the rotation speed of the second fan <NUM> and consequently the flow rate of the second comburent A, and the rotation speed of the rotating element <NUM> of the metering device <NUM> and consequently the flow rate of biomass C into the brazier <NUM>.

In other embodiments, not shown in the drawings, an element made of thermoconductive material, for example ceramic, can be attached at least to the lateral walls <NUM> of the combustion chamber <NUM>, in order to increase the thermal inertia.

In other embodiments, not shown in the drawings, one or more pipes for circulating water can be associated with at least the lateral walls <NUM> of the combustion chamber <NUM>.

With reference to <FIG>, in a second embodiment, a heating apparatus <NUM> not according to the present invention can comprise all the components of the heating apparatus <NUM> described above, except the heat exchange means M4. In this embodiment, the heating apparatus <NUM> can also comprise a second ignition device, not shown in the drawings, disposed substantially in proximity to the nozzle <NUM> and configured to trigger the combustion of the combustible gases S.

With reference to <FIG>, in a third embodiment, a heating apparatus <NUM> not according to the present invention can comprise all the components of the heating apparatus <NUM> described above, except the heat exchange means M4 and the first fan <NUM>.

Also in this embodiment, the heating apparatus <NUM> can also comprise a second ignition device, not shown in the drawings, disposed substantially in proximity to the nozzle <NUM> and configured to trigger the combustion of the combustible gases S.

With reference to <FIG>, in a fourth embodiment, a heating apparatus <NUM> according to the present invention can comprise all the components of the heating apparatus <NUM> described above, except the first fan <NUM>.

It should be noted that, in the third and fourth embodiments, the heating apparatus <NUM>, <NUM> only comprises the second fan <NUM>, connected to the combustion chamber <NUM> in order to draw the fumes F generated inside the latter.

Furthermore, in the third and fourth embodiments, a conduit connected downstream of the second fan <NUM> can be connected to the brazier <NUM> in order to function as a recirculation mean M3 to convey a first part F1 of the fumes F, which functions as a first comburent.

In other possible variants of the third and fourth embodiments, the conduit described above, which functions as a recirculation mean M3, can be disposed upstream of the second fan <NUM> and downstream of the combustion chamber <NUM> (<FIG>).

The operation of the heating apparatus <NUM> described heretofore, which corresponds to the method according to the present invention, comprises the following steps.

When the heating apparatus <NUM> is started, the control unit <NUM> drives the injection device <NUM> to introduce a certain quantity of biomass C into the brazier <NUM> and the ignition device <NUM> to ignite the biomass C in the brazier <NUM>.

Furthermore, the control unit <NUM> drives the first fan <NUM> which takes a first comburent F1 from the combustion chamber <NUM> and introduces it into the brazier <NUM>. We wish to clarify that, at start-up, substantially ambient air is present inside the combustion chamber <NUM>.

The control unit <NUM> also drives the second fan <NUM> which draws the second comburent A from the external environment, through the feed apertures <NUM>, and introduces the latter into the combustion chamber <NUM> through its entry aperture <NUM>.

In this start-up step, the combustion between the biomass C inside the brazier <NUM> and the first comburent F1, which hereafter will be referred to as start-up combustion, is substantially of the reverse flame type, also called downdraft by the people of skill in the art, that is, by introducing the first comburent F1 into the brazier <NUM> from the top downward, in such a way that it passes, in this direction, through the biomass C disposed, during use, in the brazier <NUM> and consequently generating a flame which is also directed from the top downward, and fumes.

The fumes produced by the start-up combustion are conveyed into the combustion chamber <NUM> by means of the conveyor compartment <NUM>, thanks to the draw provided by the first fan <NUM> which, subsequently, re-introduces them into the brazier <NUM>. Therefore, in this step, the first comburent F1 consists of a first part of the start-up combustion fumes.

In particular, a first part F1 of the start-up combustion fumes is drawn by the first fan <NUM> by means of the first recirculation apertures <NUM> and is re-introduced into the brazier <NUM> from its second aperture <NUM>, functioning as first comburent F1, and a second part F2 of the start-up combustion fumes is drawn in by the second fan <NUM> by means of the evacuation apertures <NUM> and is expelled from the heating apparatus <NUM>.

After a certain period of time, a steady state operating condition is reached, in which the first comburent F1 has a temperature and quantity of oxygen suitable to trigger the process of pyrolysis of the biomass C present in the brazier <NUM>.

At this point, the first comburent F1 introduced into the brazier <NUM> is suitable to thermochemically decompose the biomass C inside the brazier <NUM> and produce combustible gases S.

It should be noted that the thermochemical decomposition of the biomass C also substantially occurs in downdraft, that is, by introducing the first comburent F1 into the brazier <NUM> from the top downward, in such a way that it passes, in this direction, through the biomass C which is disposed, during use, in the brazier <NUM>. In this way, the combustible gases S produced by the thermochemical decomposition of the biomass C escape from the lower portion of the brazier <NUM>.

This configuration is advantageous in that it forces the combustible gases S to pass through the biomass C contained in the brazier <NUM> and this allows to separate their volatile components, producing combustible gases S with less TAR.

Therefore, during steady state operation, it is no longer the fumes generated by the start-up combustion that exit from the exit aperture <NUM> of the brazier <NUM>, but the combustible gases S generated by the thermochemical decomposition of the biomass C.

The method then provides to introduce the combustible gases S into the combustion chamber <NUM> by means of the conveyor compartment <NUM>, thanks to the draw of the first fan <NUM>. Furthermore, the control unit <NUM> is configured to command the operation of the recirculation means <NUM> in order to regulate the flow rate of the first comburent F1, and to command the operation of the injection device <NUM> in order to control the flow rate of the biomass C introduced into the brazier <NUM>.

The method then provides to oxidize, or ignite, the combustible gases S by means of the second comburent A introduced into the combustion chamber <NUM>, producing a flame, fumes F and developing heat.

According to the invention, the method provides to heat the second comburent A, using the heat contained in the first comburent F1 before the second comburent A reaches the combustion chamber <NUM>. This heat exchange is preferably carried out in countercurrent.

It should be noted that the ignition of the oxidation, or combustion, or fire, of the combustible gases S in the combustion chamber <NUM> occurs only by means of the "meeting" between the latter and the second heated comburent A. This is very advantageous, since it does not require the presence and use of additional ignition devices.

As before, a first part F1 of the fumes F generated, this time, by the combustion of the combustible gases S is drawn by the first fan <NUM> by means of the recirculation apertures <NUM> and is reintroduced into the brazier <NUM> from its comburent entry aperture <NUM>, functioning as a first comburent F1, and a second part F2 of the fumes F is drawn by the second fan <NUM> by means of the evacuation apertures <NUM> and is expelled from the heating apparatus <NUM>.

At this point, the first part F1 of the fumes F, re-introduced into the brazier <NUM>, and which in fact functions as first comburent F1, has an oxygen component advantageously comprised between about <NUM>% and about <NUM>% by volume, which is smaller than that present in the ambient air. This is particularly advantageous since, by doing so, an anoxic environment is created in the brazier <NUM>, that is, lacking in oxygen, which is present in a quantity sufficient to react mainly with the carbon present in the biomass C and generate the combustible gases.

Therefore, the production of polluting emissions such as, for example, nitrogen oxides, is significantly decreased since there is not a sufficient quantity of oxygen in the brazier <NUM> to bind with the nitrogen comprised in the biomass C.

Furthermore, when operating at steady state, the first part F1 of the fumes F, the moment it enters the brazier <NUM>, has a temperature comprised between about <NUM> and about <NUM>, this is advantageous since at least part of the CO<NUM> present therein is re-converted into CO, that is, carbon monoxide, which is combustible. Another advantage is that the water present in gaseous phase in the first part F1 of the fumes F in the brazier <NUM> is converted into hydrogen, increasing the calorific value of the combustible gas S.

The control unit <NUM> can also control the injection device <NUM>, the first fan <NUM> and the second fan <NUM> on the basis of the electrical signal received from the sensor <NUM>. For example, the control unit <NUM> can modify the flow rate of the first comburent F1, of the second comburent A and/or of the biomass C in feedback, until the value detected by the sensor <NUM> reaches a predetermined target value. Optionally, the control unit <NUM> also drives the third fan <NUM> to generate a flow of ambient air R which passes into the second compartment <NUM> in order to exchange heat with the evacuation pipes <NUM>, heating up. The heated ambient air R is then conveyed once again toward the external environment.

In fact, it should be noted that the injection device <NUM>, the first fan <NUM> and the second fan <NUM> allow to manage the flow rate of the first comburent F1, of the second comburent A and/or of the biomass C in a coordinated way, so as to reduce the polluting emissions of the heating apparatus <NUM> and better manage the generation of heat thereby.

It is clear that modifications and/or additions of parts may be made to the heating apparatus <NUM> as described heretofore, without departing from the field and scope of the present invention as defined by the claims.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve equivalent forms of heating apparatus <NUM> within the scope of the present invention as defined by the claims.

Claim 1:
Heating apparatus (<NUM>, <NUM>, <NUM>, <NUM>) comprising both a brazier (<NUM>) suitable to thermochemically decompose a biomass (C) and produce at least one combustible gas (S) and which in turn comprises a first entry aperture (<NUM>) to receive said biomass (C) which functions as fuel and a second aperture (<NUM>) to receive a first comburent (F1), and also a combustion chamber (<NUM>) which is autonomous with respect to said brazier (<NUM>), is delimited by a plurality of walls (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and is suitable to develop heat by means of a flame, further comprising conveyor means (M2) interposed between said brazier (<NUM>) and said combustion chamber (<NUM>) to convey said at least one combustible gas (S) to said combustion chamber (<NUM>), wherein on at least one first wall (<NUM>) of said plurality of walls (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) one or more recirculation apertures (<NUM>) are made, each of which is connected to said second aperture (<NUM>) of said brazier (<NUM>) by means of recirculation means (<NUM>) and wherein said heating apparatus (<NUM>) also comprises a containing body (<NUM>) configured to define, together with said first wall (<NUM>), a containing compartment (V) in which said recirculation means (<NUM>) are disposed,
characterized in that
said containing body (<NUM>) is also configured to receive a second comburent (A) from the external environment, in such a way that it is heated by said recirculation means (<NUM>), and to direct it into said combustion chamber (<NUM>).