BURNER ESPECIALLY FOR HEATING APPLIANCES The invention relates to a burner especially for heating appliances with the characteristics given in the main idea of claim 1. To reduce the production of harmful substances during combustion such as NOx or CO, different concepts are known. in the current state of the art. Since the production of N0X is high at the high burning temperatures, it is tried, for example, to keep the temperature of the flame low. For this purpose, patent EP 0 256 322 B 1 proposes a heating boiler in which a hot gas is burned using a platinum group catalyst at a temperature of less than 700 ° C, thereby preventing the production of oxides of platinum. In any case, such catalysts only have a relatively short life span and are also very expensive. The essential disadvantage of the burning of catalysts is, however, in their low flame temperature, which does not allow any effective use of heat and thus it only allows the construction of a burner with a low power density. In addition there are burners that work according to a procedure of the recirculation of the waste gas. Here a part of the waste gas is conducted back to the flame, which achieves an optimal burn reduction of the harmful substances. A stable flame is produced in the RotriX model burner from the Viessmann firm by means of a fuel / air mixture which is rotated by a desired swirl action.An oxidation without a flame on a free surface can increase the rate of Waste gas circulation Oxidation without flame is based on the technical study of JA Wunning and JG Wunniing "burner for oxidation without flame with low NO formation also in a high pre-heating of the air" in GASWARME international, Band 41 (1992) notebook 10, page 438-444, in burners with process temperatures above 850 ° C. However, this procedure requires a high constructive expense in the burner set, which for example for the heating of the fuel / air mixture to the ignition temperature requires auxiliary burners.Another concept is presented in the "Thermomax" burner of the Ruhrgas AG firm, which is dealt with in the technical study of H.Berg and T.Jannemann, " development of a premixed burner poor in harmful substances for application in home gas boilers with cylindrical burner chamber "in GASWARME International, BAND 38 (1989), notebook 1 p. 28-34. The combustion has place there without a flame on the surface of a metal perforated sheet which gives the thermal energy generated from the reaction zone mainly by radiation. By means of this heat emission the burning temperature is maintained at approximately 800 ° C, which again results in a decrease in the emission of harmful substances. The burners of this construction have a surface thermal power of 300 kW / m2. An increase of the thermal power to approximately 3000 kW / m2 is reached by a burner which is known from the patent application DE 4322 109 A l.There a part of the burner space in which a flame is enlarged is completely filled with a porous material , whose porosity varies in such a way along the direction of flow of the gas-fuel / air mixture in such a way that a critical number of Peclet is produced on a boundary surface or in a certain area of the porous material from the which can produce a flame. From the number Peclet the following can be said: In a certain pore size of the porous material are the production of heat by chemical reaction in the flame and the conduction of heat through the porous medium of the same magnitude so that below that pore size no flame can be produced, but above, free inflammation takes place. This condition is described with the help of the Peclet number, which gives the ratio between the production of heat and the removal of heat. In this way a number of critical Peclet is produced for the broadening or propagation of the flame. By the arrangement of a subcritical zone and a supercritical zone with reference to the number of Peclet, a self-stabilizing flame is produced within the supercritical zone.
By means of the arrangement given in DE 43 22 109 A1 the problem of the stability of a flame burning in a porous medium under the secondary condition of a low temperature and with this a scarce emission of harmful substances is solved. For example porous materials such as foam, ceramic or ballasting of spheres are proposed. These materials have, however, a relatively low porosity, with which the burning space decreases and the gas / air mixture experiences a greater resistance to the current.They also dampen these materials because of its low optical transparency in energy transport based on the heat transport mechanism of the thermal radiation that dominates in the considered temperature range which leads to a constructive size of these burners, that the heat produced in the internal zone The burner space can not be driven sufficiently well outwards. The consequences of local overheating caused in this way in the porous material are material damage due to thermal stresses and an increase in the expulsion of the harmful materials. The object of the present invention is to provide a burner with a porous medium having a high porosity and with this a high optical transparency as well as insensitivity with respect to thermal stresses. In addition, the porous material must be able to be produced simply in a simple manner. good price and with a precision that is constantly maintained in regard to the dimensions of the hollow spaces. The latter can also be varied in size without great problem. Due to their spatial structure, the packages have the additional advantage that they react elastically to the thermal or mechanical actions, thereby eliminating the danger of breaking places as they occur in the foamy ceramic parts that are used in the current state of the technique. Since the packages according to the present invention with respect to the state of the art can be manufactured with high degrees of porosity, the fraction of material with respect to the total volume is very small. This leads to a remarkable shortening of the times of use of the burner compared to the porous media known hitherto.In addition such packages can be made differently with respect to diameter, length, hydraulic diameter etc. whereby an optimum mechanical conformation of the fluid is achieved. Coordinated packages that can be used as static mixers have, together with a small pressure drop and optical transparency, other qualities that are positive. This crushing cross-section leads to a homogeneous concentration and temperature profiles of the combustion gas, which favorably influences the burn process and further reduce the production of harmful materials since there are no cold positions or so-called Hot Spots (hot spots). Due to the low amount of remezoiado marked areas are prevented as well as interruptions of the current medium and stabilizes the burn zone additionally in the current direction. In addition, it may be advantageous to twist two or more package elements to be used next to one another. This ensures a homogeneous distribution of the concentration, temperature and speed of the current across the cross section of the current. The advantages mentioned are achieved especially with a package, made of a material that is resistant to temperatures in the area between 1200 ° C and 2000 ° C (claim 2). As particularly suitable are coordinated packages such as for example static mixtures which are made of corrugated or folded zig-zag layers, lamellae forming channels where the channels cross the neighboring layers and the lamellae consist of metallic and / or ceramic materials where the package can be constructed monolithically (claim 3). Another type of package is made up of sticks that are cut in the shape of a cross and have the same characteristics as the packages, which are made of wavy lamellas. According to claim 4, the lamellae can be leaves or sheets arranged closely together, which have a multiplicity of perforations. According to claim 5, the package may consist of layers of intersecting rods made of metallic and / or ceramic materials. According to claim 6, the package may consist of ceramic materials with the main constituent parts AI2O3, Zroe or SiC. These materials have the advantage of remarkable resistance to temperature and corrosion. The advantages presented are achieved by a package, which has a part of hollow sleeve, that is with porosity, of at least 70% and a wavy height of the layers in reference to the width of the rods between 3mm to 15mm (claim 7). With these geometric data, low pressure losses can be obtained from harmful materials. According to claim 8, the package can be coated in the catalytically burned space or terminated by a catalytically active material, that is to say if it is catalytically active, thereby achieving very low emission values of harmful materials. In the entrance area of the coordinated package is placed a porous body, which acts as a flame retainer or flame blocker, which is guaranteed, that the number of existing Peclet will be non-critical, preferably less than 65. This porous body can be constructed as a coordinated package (claim 10). Claims 9 and 10 present measures to define the limitation of the flame area of the burner, where according to claim 9 a flame retainer constructed in accordance with the known state of the art is used, simultaneously being intensified by the body of fine pore the mixture between the gaseous or vapor fuel and the air. In this way conventional burners with free flame formation, which normally present such flame retainers, can be used to equip them with a package according to the invention, thus obtaining a possibility of obtaining a good cost in the reduction of harmful materials with the application of existing burners. In the alternative given in claim 10. In the direction of flow of the gas / air mixture, the flame zone defining the package has been precoordinated, a fine porous material, in which, by reason of its non-critical Pellet number, it is not can form no flame, with this the combinable concept known by the DE 43 22 109 Al for the stabilization of the flame, with the present invention is combinable. The fine porous material, which is easily manufactured as a package coordinated with a porosity, in which the Peclet number is especially less than 65 - as the own package arranged in the space of burning-made of sheet material or ceramic sheet. Here the fine pore package should not only serve for the stabilization of the flame, but because of the cross-mixing properties, the burning gases, such as natural gas, methane or hot oil vapor, should be mixed homogeneously with the air before the combustion space itself, which will favorably influence the combustion process especially with regard to the emission of harmful materials. Other features and advantages of the invention are apparent from the following description, in which exemplary embodiments will be explained with reference to the drawings, in which: Figure 1 shows a coordinated ceramic package; Figure 2 shows a schematic longitudinal section through a burner in a first mode; Figure 3 a schematic longitudinal section through a burner in a second embodiment; Figure 4 shows a typical axial course of temperature inside the burner. The package shown in Figure 1 is composed of multiple corrugated ceramic plates. These ceramic plates are arranged in such a way that the waves of two neighboring corrugated plates form an angle of 60 °. In this way, open channels that intersect are produced. The burner shown in Figure 2 presents a box 1 with a main part 2 and a top closing part in the form of a truncated cone 3. This closure has on its upper side an inlet 4 for a gas / air mixture as a fuel mixture, in the direction of passage of the stream D of the gas / air mixture follows before the pre-chamber 5 formed by the closing door 3, a conventional flame retainer or a perforated plate 6, through which the gas / air mixture penetrates. in the next space for burning 7. This is filled with a package 8, which presents, for example, the following specification: Diameter: 70 mm Height 90 mm Porosity approx. 95% Wave height 8mm Heat-resistant ceramic material The gas / air penetrating mixture in the package is lit by means of a lighter device 9 which sits at the height of 1 burning space 7 on one side of the box 1 , and burns forming a defined flame zone within the coordinated package 8 generating thermal energy. This occurs largely in a thermal radiation, which heats the main part of the box 2. The main part 2 is surrounded by a heat transfer jacket 10, where channels 11 running helically, through these have been provided. a heat-carrying medium, such as water, flows through a heating device. It is coordinated to the space of burning in the direction of stream D a space of waste gas 12, where a temperature between 700 and 1300 ° C prevails at the entrance of that area and between 35 and 150 ° at the exit of that area. The waste gas space 12 serves as a cooling zone, where the cooler made of stainless steel 14 removes heat from the waste gas, which is used as usable heat. The cooler is maintained by the passage of a current with the heat carrier medium at temperatures below 200 ° C, so that also other materials, especially aluminum, brass, or copper, can be used. The space of the waste gas 12 it flows into outlet 13 of the burner. The burner shown in Figure 3 differs from the burner according to Fig. 3 only in two details. As long as the construction parts coincide, the figures will be the same and will not be explained. Unlike Fig. 2, the burner according to Fig. 3 shows no conventional flame retainer, but is coordinated to the package 8 before it, a thin pore package 15 in the direction of current flow D of the air / air mixture. gas, 15 is also formed of a coordinated package, so that its Peclet number is less than 65 and with this it is below the critical value. This means that in the coordinated package 15 no flame can be formed. The coordinated packet 8 is specified in such a way that the number of Peclet is supercritical, so that a flame or flame can be formed there in a defined manner. In addition, a static mixer (claim 11) is pre-connected to the burner. It causes a very homogeneous air / gas mixture. the temperature course shown in Fig. 4 on a 6 kW natural gas burner with a power of 3 kW and an air number of 1.2, shows that the maximum temperatures occur a little after passing between the zone of fine porosity A and the zone of rough porosity C and can be in the area of 1400 to 1500 ° C. In the adjoining area D there are temperatures of approximately 1100 ° at the entrance, temperature that sinks to the exit at a temperature in the order of medium heat carrier. The fuel in the form of a gas can be, for example, hot oil or diesel oil. It should also be noted that in the flame zone defined by the coordinated package 8 the flame formed by the ignition of the gas / air mixture widens in dependence on gas and air as well as its quantities. In general, the burner power can be regulated by the amount of gas as well as the gas / air mixture quantity.