Patent Application
20070037104
The present invention generally relates to the field of reduction of environmental pollution, particularly air pollution caused by the emissions of apparatuses, such as internal-combustion vehicle engines (Otto cycle, Diesel cycle), burners for heating systems, generators of vapor for electric power generation plants, whose operation involves the combustion of fuels, for example fossil fuels such as hydrocarbon fuels or hydrocarbon containing fuels such as petroleum, including natural gas, coal, wood and similar. In particular, the invention relates to a method, and a related apparatus, for reducing combustion residues, particularly noxious pollutants, in exhaust gases.
The problem of environmental pollution is nowadays very felt by people and governments, and efforts are constantly made to find out solutions for reducing the various human activities impact on the environment.
In particular, air pollution caused by the emissions of apparatuses such as internal-combustion vehicle engines (based on Otto cycle or Diesel cycle), burners for heating systems, steam boilers for electric power plants, whose operation involves burning fuels, particularly fossil fuels, such as hydrocarbon fuels or hydrocarbon containing fuels like petroleum, including natural gas, and coal, was probably the first aspect to be recognized in the more general problem of environmental pollution.
Although the problem of massive emissions of pollutants into the atmosphere was starting with the invention of the steam-power machine at the industrial revolution dawn, it was the impressive growth of circulating vehicles in urban areas in the decades after the second world war which brought the problem in foreground.
Thus, on one side, measures restricting vehicles circulation were and are still adopted when the situation reaches at crisis level. On the other side, and in parallel, under the pressure of governments and of the public opinion, vehicle manufacturers and research institutes have started to study solutions for the problem of emissions of noxious pollutants by internal-combustion engines.
For example, in the European Union geographic area the maximum levels of tolerated vehicles emissions have been set by law, and a system of classification has been introduced for vehicles engines based on their respective level of pollutants emissions, in particular, since January 2001, the previous standards known as EURO1 (introduced in 1987) and EURO2 have been replaced by the more restricted standard EURO3, which will be replaced by the even stricter standard EURO4 since January 2006. This classification imposes that vehicles falling in the lower classes are not allowed to circulate in case restrictive measures are issued by governments or public administrations in consequence to a crisis situation approaching.
The main pollutants present in exhaust gases of internal-combustion engines, particularly of Diesel type, are carbon oxide (CO), carbon dioxide (CO2), uncombusted hydrocarbons (HC), various nitrogen oxides (NOx), and Particulate Matter (PM), especially carbon particulate.
Similar substances are found in the exhaust gases of heating implants and, more generally, of any apparatus whose action involves the combustion of fuels, particularly fossil fuel.
Each one of the above mentioned substances is noxious to human health for one or more reasons, causing cancer, lung disease and others. Thus, it would be extremely important to reduce as far as possible, or possibly eliminate, these substances from the exhaust gases.
In view of the state of art above outlined in the foregoing, an object of the present invention has been to provide an effective solution to the pollution problem due to the internal combustion engines emissions and, more generally, to the problem of environmental pollution due to the emissions of any apparatus whose action involves the combustion of fuels, particularly but not limitatively fossil fuel, such as hydrocarbon fuels or hydrocarbon containing fuels such as petroleum, including natural gas, and coal, or even wood, and generally any fuel that can be used in a combustion process.
The Applicant has found that noxious pollutants (gases, dust, particulate material, particularly carbon particulate) which are normally produced by apparatuses whose operation involves the combustion of fuel, particularly but not limitatively fossil fuel, such as internal combustion engines and burners of heating systems of buildings, can be substantially reduced, not to say completely eliminated, if the exhaust gases are submitted to a treatment that involves a post-combustion of the exhaust gases, and particularly a radiant post-combustion, ignited by submitting the exhaust gases to radiant energy, providing for a relatively fast increase of the exhaust gases temperature to a value in a properly chosen temperature range, adapted to essentially destroy the pollutants present in the exhaust gases.
For the purposes of the present description, by radiant combustion there is intended a combustion process that is ignited by a heat source not involving the presence of a flame, but irradiating electromagnetic energy, particularly in the range of wavelengths from InfraRed (IR) to UltraViolet (UV).
In other words, the Applicant has found that by submitting the exhaust gases to radiant energy in a suitably designed radiant reactor, wherein the gases are subjected to a relatively fast increase of their temperature, up to a value in the properly chosen temperature range, a substantially perfect post-combustion is achieved, where, for the purposes of the present invention, by “perfect” there is meant a post-combustion that allows substantially the elimination of any noxious component or substance, such as CO, CO2, HC, nitrogen oxides, PM, in particular carbon particulate, sulphur oxides, from the exhaust gases that are originated by the combustion of fuels.
According to a first aspect of the present invention, a method for reducing pollutants in exhaust gases generated from the combustion of fossil fuel as set forth in the appended independent method claim 1 is thus provided.
Summarizing, the method comprises treating the exhaust gases before releasing them in the environment, by performing a post-combustion process according to which the exhaust gases are submitted to radiant energy so as to increase a temperature thereof to a value sufficient to ignite self-combustion.
According to a second aspect of the present invention, there is also provided an apparatus for reducing pollutants in exhaust gases generated from the combustion of fossil fuel, as set forth in the appended independent apparatus claim 16.
In brief, the apparatus comprises means for treating the exhaust gases before releasing them in the environment, such treating means comprising a radiant combustion chamber wherein the exhaust gases are caused to pass through, so as to be submitted to radiant heat for increasing a temperature thereof to a value sufficient to ignite self-combustion, thereby a post-combustion process of the exhaust gases is performed before releasing them in the environment.
These and other features and advantages of the present invention will be made apparent by the following detailed description of some embodiments thereof, provided merely by way of non-limitative examples, description that will be conducted making reference to the annexed drawings, wherein:
With reference to the drawings, in
The pollutants-reduction apparatus, denoted globally as 100, is schematically depicted as placed downstream a block 105, representative of a generic apparatus of any type whose operation involves the combustion of fuels, particularly fossil fuels such as hydrocarbon fuels or hydrocarbon containing fuels such as petroleum, including natural gas, coal, wood, and the like, generally any fuel adapted to be used in a combustion process; for example, the apparatus 105 may be an internal-combustion engine of a vehicle, particularly but not limitatively of the Diesel type or based on the Otto cycle, or a burner of a heating system for buildings, or steam boilers for electric power plants. Downstream the pollutants-reduction apparatus 100, a block 110 is provided, schematically representing an exhaust system of any conventional type, for example a simple muffler of a vehicle.
In greater detail, the pollutants-reduction apparatus 100 has an input manifold 115i, for receiving combustion exhaust gases from the apparatus 105; the received exhaust gases are treated by the apparatus 100 before being released in the environment; the pollutants-reduction apparatus 100 has an output manifold 115o for delivering treated exhaust gases to the exhaust system 110 (it is however observed that the exhaust system 110 might also not be provided for, and the treated exhaust gases be released directly into the environment).
The input manifold 115i leads the exhaust gases to be treated to a gases pre-heating chamber 120, where the exhaust gases, received from the apparatus 105 at a relatively low temperature, are submitted to a preliminary heating process. Considering for example the case of exhaust gases from an internal combustion engine, particularly of the Diesel type, the temperature of the exhaust gases should in theory be around 400-450° C.; however, experimental trials conducted by the Applicant have revealed that the exhaust gases temperature is normally lower, falling in the range from approximately 150° C. to approximately 300° C. The preliminary heating process in the pre-heating chamber 120 brings the exhaust gases temperature to a suitably higher value, preferably a value higher than 400° C., for example a value in the range from approximately 400° C. to 700° C. and, preferably, from approximately 550° C. or 600° C. to approximately 700° C.
In an embodiment of the present invention, the pre-heating chamber 120 comprises means adapted to submitting the incoming exhaust gases to a compression, thereby the gases temperature rises. In particular, the pre-heating chamber 120 may comprise means adapted to impart a suitable acceleration to the exhaust gases, and particularly one or more among a fan (or an arrangement of fans), a turbine (or an arrangement of turbines), a turbo compressor; these elements are only schematically indicated in
Preferably, downstream the means 121 for accelerating the exhaust gases, a Venturi tube (schematically represented in
From the pre-heating chamber 120, the pre-heated gases are conveyed to a radiant combustion reactor or radiant combustion chamber 125, situated just downstream the Venturi tube 123.
The radiant combustion chamber 125, several practical embodiments of which will be described in greater detail later on, is a chamber with walls made of suitable material, which are heated by a heat source to a prescribed temperature, thereby the chamber walls radiate electromagnetic energy within the chamber (in the way that approximate the black-body radiation). Within the radiant combustion chamber 125 the temperature of the exhaust gases is raised further and rather quickly from the pre-heating temperature, for example the initial approximately 700° C., to a temperature in the range from approximately 900° C. to approximately 1200° C., preferably from approximately 900° C. to approximately 1100° C., suitable to determine a combustion (post-combustion) of the exhaust gases; more generally, the upper limit of the temperature of the exhaust gases may be chosen in such a way that, at such a temperature, the creation of nitrogen oxides is not relevant; thus, the maximum temperature of the gases within the combustion chamber 125 may reach 1300-1400° C. or even higher temperatures, for example up to 1800° C. The increase in temperature is achieved by radiant electromagnetic energy, particularly in the wavelength range from IR to UV, radiating from the walls of the radiant combustion chamber 125. In case no pre-heating is provided for, within the radiant combustion chamber the exhaust gases temperature should be raised from the above-mentioned initial 150° C.-300° C. to the desired high temperature.
A possible explanation of the exhaust gases temperature increase within the radiant combustion chamber can be found in the radiating effect, according to which the transfer of energy from the walls of the radiant combustion chamber to the exhaust gases is proportional to the fourth power of the temperature in Kelvin degrees.
By subjecting the exhaust gases to such a fast increase in temperature, the exhaust gases post-combustion process that is automatically ignited allows substantially reducing or even eliminating the harmful, uncombusted particulates present in the exhaust gases. In particular, in the exhaust gases, typically being a mix of oxygen, uncombusted hydrocarbons, carbon particulate, self-combustion is automatically ignited, because the gaseous fluid in the chamber 125 travels in an environment at a temperature which is higher than the self-combustion temperature (the specific value of which depend on the substances present in the exhaust gases), and the combustion is carried out exploiting the radiant energy irradiating from the walls of the chamber 125. This substantially improves the efficiency of the combustion of the carbon particulates, which is more difficult than that of hydrocarbons because the combustion time is related exponentially to the size and shape of the particle.
It is observed that by ensuring that the gas temperature in the radiant combustion chamber,125 is sufficiently high, in particular higher than approximately 450° C., preferably in the range from approximately 900° C. to approximately 1200° C., and more preferably from approximately 900° C. to approximately 1100° C., or higher, up to 1800° C. (generally, a temperature below the temperature at which nitride oxides start forming), nitride oxides already present in the exhaust gases are reduced. To this purposes, the post-combustion process of the exhaust gases may be combined with known reduction processes, such as the Non-Selective Catalytic Reduction (NSCR) process, in presence of oxygen (by providing a suitable feed of oxygen to the radiant combustion chamber, or the Selective Catalytic Reduction (SCR) process, in presence of a noble catalyst (e.g., platinum), maintained at high temperature by the flow of the exhaust gases. It is pointed out that the NSCR and the SCR processes may be exploited in alternative to one another, or in combination, depending in particular on the structure, e.g. on the geometry, of the radiant combustion chamber 125.
It is also observed that, in the radiant combustion chamber 125, the post-combustion of the exhaust gases takes place at a constant pressure.
In
Optionally, a first filtering element 130a is arranged along the radiant combustion chamber 125 (for example, the radiant combustion chamber 125 may be made up of two parts in cascade, and the filtering element 130a may be arranged between the first and the second part).
Upon leaving the radiant combustion chamber 125, the post-combusted exhaust gases are led to a second filtering element 130b.
Each one or both of the filtering elements 130a and 130b may comprise active and/or inactive filters, particularly selective filters, preferably active nanofilters in ceramic/zeolite material, and are used for trapping residual dust and Particulate Material (hereinafter, shortly, PM) still present in the exhaust gases after the post-combustion process in the radiant combustion chamber 125. An active filter generally acts as a catalyzer with oxidation reactions; active filters typically are based on metals. An inactive filter is essentially a trap. It is observed that using for example zeolite materials, both active and inactive filters can be realized (placing a zeolite in a bath of gold or palladium produces an active filter). In particular, the first filtering element 130a, if provided, allows trapping the residual, uncombusted dust and PM present in the exhaust gases after a first post-combustion phase, while the second filtering element 130b, positioned at the output of the radiant combustion chamber 125, serves for trapping the uncombusted dust and PM still remaining in the exhaust gases after the post-combustion. Depending on the type of nanofilters adopted, the filtering elements may act both as hot catalysts, and as pure filters,
It is pointed out that the specific arrangement, the number and the dimensions of the nanofilters making up the filtering elements 130a and 130b will depend on the specific type of apparatus 105 to which the pollutant-reduction apparatus 100 is intended to be associated with. However, as a general rule, nanofilters resistant to high temperatures should be used.
It is also observed that more than one intermediate filtering element 130a may be provided along the radiant combustion chamber.
Preferably, the filtering elements 130a and 130b are removable from the apparatus 100 and, even more preferably, they are also reconditionable or recyclable.
Optionally, means suitable to favor the exit of the post-combusted gases from the radiant combustion chamber 125 are provided, as shown in phantom and indicated by 127 in
After being passed through the second filtering element 130b, the treated exhaust gases (substantially freed of the harmful pollutants) are led to a heat exchange arrangement 135. In the heat exchange arrangement 135 the temperature of the treated exhaust gases is lowered from the approximately 900° C.-1200° C. to values suitable to avoid thermal shocks, such as a temperature value of approximately 100° C.-150° C. or lower, from approximately 50° C.-150° C.
Expediently, as schematically depicted in the drawing, the heat exchange arrangement 135 is arranged in such a way that at least part of the heat released by the treated exhaust gases is exploited for pre-heating the incoming gases to be treated in the pre-heating chamber 120, thereby alleviating the burden of the exhaust gases acceleration means.
Preferably, the heat exchange arrangement 135 is made of materials resistant to high temperatures, particularly sodium, lithium, titanium, etc.), and it may be of the molded metal type, of the liquid metal type, of the plate type, of the spiral type; in case the apparatus 100 is intended to be installed on a vehicle, the heat exchange arrangement shall have a suitably compact design.
From the heat exchange arrangement 135, the treated exhaust gases, from which the harmful pollutants have been substantially eliminated, are led to the output manifold 115o, and then to the exhaust system 110 (for example, the muffler of the vehicle).
A control unit 140 is provided in the apparatus 100 for controlling the operation of the various components thereof (as schematized by the dash-and-dot lines in the drawing). In particular, the control unit 140 comprises electronic control means, preferably programmable, particularly microprocessor-based control means, adapted to execute suitable microprograms for implementing a predefined control flow, and sensors, such as pressure sensors and temperature sensors for detecting the operating temperature in the different parts of the apparatus 100, such as the pre-heating chamber 120, the radiant combustion chamber 125, the heat exchange arrangement 135, the pressure and/or velocity of the exhaust gases in different points of the path, and sensors for establishing the percentages of the various pollutants in the exhaust gases. The control unit may control the heating of the radiant combustion chamber.
The specific controls operated by the control unit 140 depend largely on the structure of the radiant combustion chamber 125, but in general the control unit 140 shall at least ensure that a correct temperature is maintained within the chamber 125.
In the following of the present description, several different embodiments of the radiant combustion chamber 125 will be presented, being however intended that the list of presented alternatives is not to be intended as exhaustive, and several other embodiments can be devised. It is in fact pointed out that the specific spatial configuration and structure of the radiant combustion chamber 125 may depend on the specific application.
In the embodiment shown in axonometric view in
In the embodiment shown in axonometric view in
The radiant combustion chamber 125 in the embodiment shown in
The radiant combustion chamber 125 in the embodiment of
A still different embodiment of radiant combustion chamber 125 is the one depicted in
It is observed that if, as in the schematic arrangement of
In a slightly different way, in the embodiment of
Clearly, in both the two latter embodiments a resistor supply arrangement should be provided for, for example similar to those described in connection with the first embodiments presented.
It is observed that the specific dimensions and the material of the ducts (e.g. the radiant tubes) making up the radiant combustion chamber 125 depend on the specific application; suitable materials that can be used for realizing the radiant ducts are for example INCONEL (an alloy containing tungsten and manganese) and ceramic. Radiant tubes are also commercially available.
It is observed that the resistor power supply, controlled by the control unit 140, should preferably be controlled so as to track changes in operating conditions, particularly of the apparatus 105. For example, in some applications, such as in the case of vehicles, an increased flow of exhaust gases inside the radiant combustion chamber 125 in consequence of, e.g., an acceleration of the vehicle, will require a possibly fast adaptation of the power delivered by the heating resistances, so as to maintain the temperature within the chamber 125 in the desired range.
In order to avoid dispersions of energy, the radiant combustion chamber 125 is preferably thermally insulated (this has been schematically depicted in the embodiments of
The embodiments of radiant combustion chamber 125 described up to now, albeit differing from each other in spatial configuration, are all based on a common, similar heating principle, involving the use of electric resistances as Joule-effect heaters.
Hereinbelow, some further embodiments of the radiant combustion chamber will be presented which are based on a different heating principle.
In detail, instead of using Joule-effect heaters and, particularly, electrical resistors, one or more optical radiation source, particularly one or more lasers are exploited for triggering the radiant reactor, i.e. for heating the radiant combustion chamber to the desired temperature.
Lasers are more and more widely exploited in several applications, either in industry and in consumer products, thanks to the fact that the emitted optical radiation has is very homogenous and concentrated, and that they have a very fast response.
In detail, the radiant combustion chamber 125 comprises a combustion reactor enclosure 1000; the spatial configuration of the combustion reactor enclosure 1000 is not limitative to the present invention, depending for example on the specific application: thus, in
Outside of and around the combustion reactor 1000, an arrangement of optical radiation reflecting/deflecting elements 1010 is provided, such as mirrors and/or optical prisms, schematically depicted in the drawing as the internal faces of walls of a box-shaped casing 1007 containing the combustion reactor 1000.
The arrangement of optical radiation reflecting/deflecting elements 1010 reflects/deflects optical radiation 1015 which is generated by one or more optical radiation sources, particularly lasers, schematically indicated in the drawing at 1020. It is observed that the number and the arrangement of the lasers 1020 is not limitative to the present invention, depending for example on the shape of the combustion reactor 1000; in the drawing, just by way of example, four lasers 1020 are shown, each one located at a respective corner of the box 1007; the lasers 1020 may be fixed or movable, for example they can be partially rotate and/or be angularly oriented.
The optical radiation emitted by the laser(s) 1020, controlled by the control unit 140, is reflected/deflected by the optical radiation reflecting/deflecting elements 1010, and hits the external side of the walls of the combustion reactor 1000, causing a substantially uniform heating thereof. In this way, the walls of the combustion reactor are brought to the radiative temperature, i.e. to a temperature such that a sufficient electromagnetic energy is radiated from the walls of the combustion reactor into the enclosure 1000.
In the following, some possible practical embodiments of radiant combustion chamber 125 exploiting the optical-based heating mechanism, particularly the laser-based heating, will be presented, being intended that such embodiments are mere examples.
In particular, in the embodiment schematically shown in
It is observed that in
A slightly different arrangement is schematically depicted in
The substantially spherical shape of the combustion chamber 125 in the embodiment of
It is observed that by properly disaligning the inlet and the outlet of the gases into/from the reaction chamber, a vortex can be created inside the reaction chamber that, proximate to the chamber outlet, optimizes the gas recirculation, favoring the exit of the portion at a higher temperature. This is further helped by the Venturi accelerator 127 that may be placed at the exit of the chamber.
The use of one or more lasers for heating the radiant combustion chamber has the advantage of allowing a substantial reduction in the dimensions of the combustion reactor, because when turned on the laser(s) cause the reactor walls to almost instantly reach the desired operating temperature (necessary for inducing self-combustion of the exhaust gases), and, similarly, the laser(s) can be turned off almost instantaneously.
A suitable number of sensors may be associated with the walls of the radiant combustion chamber so as to enable the control unit 140 causing the laser radiation to hit the desired areas of the radiant combustion chamber walls, scanning the surface according to prescribed patterns in such a way as to cause the surface be homogeneously hit.
In particular, a specific control software may be executed by the control unit 140, according to which the surface to be hit by the laser radiation is subdivided according to several different parameters, such as the temperature of the areas already hit by the radiation, the difference in temperature between these areas and those not yet hit (the cold areas), the target temperature. A dynamic temperature map is thus built, and such a map, in addition to being used by the control unit to control the laser, might also be displayed, on suitable display devices, to an operator, so as to enable constantly control the operation of the apparatus.
The control software may be based on variation calculations or on perturbation calculation, or on a simpler “fork shoot” (a term derived from the navy jargon and indicating a successive approximation process).
Moreover, the use of laser(s) allows a better controllability of the whole post-combustion process. In fact, by properly driving the pulsed laser(s) through the suitably programmed control unit, the post-combustion process of the exhaust gases can be controlled finely in dependence of the density of the exhaust gases and their velocity, which in turn depend on the engine's RPMs and on the engine operating temperature.
Additionally, the use of laser(s) reduces the energy consumption, because only relatively high peak energies are required.
The use of lasers thus allows reducing the operation costs.
Those skilled in the art will readily understand that the lasers used, and their optical power, may vary depending on contingent needs, according to the specific applications. The laser(s) may be operated in Continuous Wave (CW) mode or, preferably, in pulsed mode. also, the laser(s) may be of rotating type, or a laser(s) emitting multiple beams properly out-of-phase.
The embodiments shown schematically in
In particular, in
A suitable drive arrangement is also provided, not shown in the drawings, for causing the rotor 1405 to rotate about its axis inside the chamber.
If, for example, a laser source is used for heating the radiant combustion chamber, as in the embodiment of
The exhaust gases to be treated are conveyed into the chamber through an inlet 1410i; within the radiant combustion chamber, the rotation of the rotor 1405 causes a dynamic partition of the internal space of the chamber into three dynamically-varying portions, and facilitates the flow of the gases towards an outlet 1410o or 1400o′; while flowing from the inlet to the outlet, the gases undergoes a post-combustion process due to the radiant energy radiating from the walls of the chamber 1400.
It is observed that the inlet 1410i and the outlet 1410o or 1400o′ to/from the radiant combustion chamber can either be axially aligned or not, and either the inlet or the outlet 1410o or 1400o′ or both may even be perpendicular to the chamber axis. As mentioned in the foregoing,
In the embodiment of
Finally, in the embodiment of
As already pointed out, the embodiments shown in
The Applicant has found that thanks to the method and apparatus of the present invention, approximately 90% of the carbon monoxide, carbon particulate, uncombusted hydrocarbon (CxHy) are eliminated from the exhaust gases, and nitrogen oxides (NOx) are reduced of almost 90%.
The method and apparatus according to the present invention find application in any system wherein combustion of fuels is provided for, such as for example internal-combustion engines, using Diesel fuel, gasoline, methanol, mix of alcohols, natural gas, LPG, Kerosene, fuel oil, hydrocarbons mixed with water, GECAM, BLUDIESEL, fuel for planes with additives, masut for marine engines.
It is observed that the post-combustion process carried out in the radiant combustion chamber may be either continuous, partially continuous or discontinuous (intermittent). By continuous there is intended a process wherein there is no substantial separation between the incoming, relatively cold exhaust gases to be treated and the outgoing, hot and already treated exhaust gases: the cold phase is contiguous to the hot phase. A partially continuous post-combustion process is one in which there is a certain separation in time (for example, of the order of 10−6 to 10−2 seconds) between the cold and the hot phases, i.e. between the cold and the hot gases; this is for example the case where a combustion chamber such as those of the embodiments of
It is pointed out that the method and apparatus according to the present invention can be used in conjunction with other known pollutants-reduction methods and apparatuses, particularly those directed to eliminating nitrogen oxides (NOx), such as Ignition Time Retardation (ITR), advanced systems of reactant injection, such as the RJM Aris™ technology, water injection, emulsions, turbocompressed air, air mixed to a fuel, Exhaust Gas Recirculation (EGR) systems, introduction of refrigerated air, high injection pressure and change of air/fuel proportion, a turbo composite, and the like. In particular, all these known techniques are preferably implemented downstream the apparatus of the present invention.
The method and apparatus of the present invention can also be used in conjunction with the known devices for eliminating sulphur oxides, particularly sulphur dioxide (SO2) and sulphuric oxide (SO3).
The apparatus according to the present invention can take the form of a kit ready to be installed on a vehicle, as a retrofit
The method and apparatus according to the present invention are capable of reducing substantially the emissions of vehicles propelled by internal-combustion engines, and also hybrid-propulsion vehicles, with both electrical and internal-combustion propulsion, will greatly benefit of the apparatus.
Although the present invention has been disclosed and described by way of some embodiments, it is apparent to those skilled in the art that several modifications to the described embodiments, as well as other embodiments of the present invention are possible without departing from the scope thereof as defined in the appended claims.
For example, other types of radiant combustion chamber might be exploited, particularly radiant combustion chambers provided with different heating means, such as gas burners.
| Number | Date | Country | Kind |
|---|---|---|---|
| MI2003A000571 | Mar 2003 | IT | national |
| M12003A002179 | Nov 2003 | IT | national |
| MI2003A002180 | Nov 2004 | IT | national |
This application claims priority to PCT Application No. PCT/EP2003/051113 filed Dec. 30, 2003, which claims priority to Italian Patent Application Nos. MI2003A000571 filed Mar. 21, 2003, MI2003A002179 filed Nov. 12, 2003, and MI2003A002180 filed Nov. 12, 2003, which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP03/51113 | 12/30/2003 | WO | 8/28/2006 |
