Improved burner,particularly suitable for wall-mounted boilers

DESCRIPTION

The present invention relates to a burner which, by providing a perfect and economical air-gas mixture with a very low pressure drop, a perfect speed distribution of the mixture in the combustion zone, a very small volume of the upstream mixture of said combustion zone, no possibility of self-induced noise and total absence of abnormal deformation in said combustion zone, results in a rational, effective operation, Quiet and reliable with minimal environmental pollution.

As is well known, boilers for central heating and / or for the production of domestic hot water, whether floor or wall, induced or forced current, or natural gas type or LPG combustion, give rise to products of combustion nqe ss find <nilre the most common causes of atmospheric coelamlllaiéOe. In this regard, in addition to carbon dioxide and water vapor, such combustion products also contain, due to the non-uniformity of the flame, which comprises a very rich central zone of very high temperature mixing, nitrogen oxides that not only they irritate the eyes and nasal mucous membrane but also have negative effects on the cardiovascular and renal system, and are also a cause of the well-known acid rain when atmospheric moisture is present.

In order to limit the formation of these Oxides it is therefore necessary to limit the combustion temperature, which is achieved substantially by premixing the air and the fuel to obtain a uniform mixture, sufficiently (ΡΑΠ, that is to say with a minimum excess of air over the stoichiometric quantity, capable of burning correctly but at the lowest possible temperature.

To this end, the burner generally comprises an air / gas mixing zone with excess air, an expansion and distribution zone of the mixture and a metal grid behind which combustion takes place. However, this known type of burner suffers from a series of drawbacks, the most serious of which is determined by the torsional deformation of the grid that occurs particularly at low loads, when the flame touches the grid.

Other drawbacks include the difficulty of achieving a good air-gas mixture and of uniformly distributing the mixture upstream of the combustion grid, the imminent risk of expiMn if the flame returns through the perforations of the grid due to the presence of a large volume of fuel mixture upstream of said grid, and a high level of noise due to self-induced pressure pulsations inside the burner by the ieleracc, mixed / flame.

In the current state of the art, propositions are already known to obviate some of these disadvantages: for example, to prevent deformation of the combustion grid, ceramic gratings or metal gratings have been used, provided with a light cover of teasic [iilracióe;

in turn, good air-gas mixing and uniform distribution of the mixture can be achieved at the expense of a high pressure range by means of suitable costly diverters and fans.

However, none of the burners known in radiography is currently able to obviate all the aforementioned drawbacks with economic and rational means, which is the object of the present invention.

This is achieved in practice by the fact that the burner, comprising a fuel gas supply duct, a combustion air supply duct and a mixing chamber, eda. prooivio in its upper part, according to a feature of the present invention, of a chamber perforated by its lower part and opened at the top, filled with small substantially spherical elements that can be made of ceramic material or of another metallic or non-metallic material and of equal or different dimensions, through the interstices of which the mixture is flowed and over which combustion takes place.

In this way a perfect mixing and a uniform distribution of the mixture are ensured by the sinuous paths through the interstices of the substantially spherical elements that now have to travel the gas and the air, reducing the presence of said elements substantially the volume of Flammable material present upstream of the combustion zone and, therefore, the risk of any return of the flame. In addition, since there is no grid, no deleterious deformation occurs in the combustion zone, in which the substantially spherical locks are free to expand without restriction, and additionally, as experimental tests have shown extensively, the system does not It allows the self-induction of noise with the result that the burner is completely silent under any load condition.

According to preferred embodiments of the invention, said small substantially spherical elements are held together either by a suitable container provided in its lower part of perforations or by welding at its contact points to form a unique nougat-like package of substantially elements. spherical

The invention will be described in more detail in continuation with r'eiac, or in the attached drawing, which illustrates a preferred embodiment thereof given by way of non-limiting example in that technical or constructive modifications can be made thereto without departing from the Scope of the present invention.

In said drawing, a burner is provided globally with a fuel gas supply line 2, a combustion air supply line 3 and a mixing chamber 4. Said burner 1 is provided, in its upper part, of a chamber 5 that was open at its top and was provided with perforations 6 at its base, said chamber being filled with small ceramic elements 7, spherical or substantially spherical, thereof

ES 2 062 913 A2 size, which are welded together at their contact points to form a single turrun-like package of spherical elements 7.

Describing sufficiently the nature of the invention, as well as the way of putting it into practice, it is stated that everything that does not alter, change or modify its fundamental principle may be subject to variations in detail. It is also noted that this invention corresponds to that described in Patent Application No. MI 91 A 002368, filed in Italy on September 6, 1991, whose priority is claimed in accordance with the International Agreements in force, the essential being and Therefore, an Invention Patent is requested for twenty years, which is summarized in the following claims:

ES 2 062 913 A2