Patent application title: MULTIFLAME BURNER WITH FLAME
Anton Imgrundt (Flensburg, DE)
Johann Stocker (Gilching, DE)
IPC8 Class: AF23D1446FI
Class name: Combustion burner having electrical heater or igniter
Publication date: 2013-10-31
Patent application number: 20130288187
A multiflame burner with burner nozzles which can be loaded with fuel
gas, particularly for thermal material processing methods, in which at
least one of the burner nozzles is provided with at least one auxiliary
nozzle opening for generating an auxiliary flame arranged laterally to a
main nozzle arrangement for generating a working flame and in the
direction of at least one adjacent burner nozzle.
1. A multiflame burner comprising burner nozzles that can be supplied
with combustible gas, wherein the multiflame burner is constituted as a
manual burner or machine burner for operation with acetylene as a
combustible gas, and wherein at least one of the burner nozzles is
provided with at least one secondary nozzle opening for generating a
secondary flame said secondary nozzle opening being disposed at the side
of a main nozzle arrangement for generating a working flame, the
orientation of said secondary flame having a directional component in the
direction of an adjacent burner nozzle, characterised in that at least
one of the burner nozzles is provided with two or more secondary nozzle
openings on at least one side of the main nozzle arrangement.
2. The multiflame burner according to claim 1, characterised in that at least one secondary nozzle opening and/or at least one nozzle channel associated with the secondary nozzle opening is disposed at an angle to the main nozzle arrangement and/or a nozzle channel associated with the main nozzle arrangement.
3. The multiflame burner according to claim 1, characterised in that at least one of the burner nozzles is provided with secondary nozzle openings for generating secondary flames in the direction of at least two adjacent burner nozzles.
5. The multiflame burner according to claim 1, characterised in that at least one of the burner nozzles is provided with a plurality of linearly disposed secondary nozzle openings.
6. The multiflame burner according to claim 1, characterised in that at least one of the burner nozzles is equipped for the ignition of an adjacent burner nozzle by means of at least one secondary flame.
8. The multiflame burner according to claim 1, which is set up for the ignition of at least one burner nozzle by means selected from the group consisting of a manual ignition device, a spark plug and a piezo igniter.
9. A burner nozzle for multiflame burners which is supplied with combustible gas, characterised in that at least one secondary nozzle opening for generating a secondary flame said secondary nozzle opening being disposed at the side of a main nozzle arrangement for generating a working flame, the orientation of the secondary flame having a directional component in the direction of an adjacent burner nozzle.
10. A thermal material processing method, in which a multiflame burner is used, wherein at least one burner nozzle is ignited by means of a secondary flame of an adjacent burner nozzle.
11. The thermal material processing method according to claim 10, further comprising a step selected from the group consisting of flame brazing, fusion bonding, flame blasting, preheating, postheating, soaking, drying and thermoforming.
12. The multiflame burner according to claim 1, which is used for thermal material processing methods.
13. The multiflame burner according to claim 9, which is used for thermal material processing methods.
 The present invention relates to a multiflame burner with burner
nozzles which can be loaded with fuel gas, particularly for thermal
material processing methods, a burner nozzle of a multiflame burner of
this type, which can be loaded with fuel gas, and also a method for
thermal material processing, in which a multiflame burner of this type is
 Although the present invention is described in the following with reference to certain thermal material processing methods, it may be emphasised that the multiflame burners according to the invention can also advantageously be used in other fields of application, just like the corresponding burner nozzles. For example, the present invention can be used for flame soldering, fusion, for example of flame spray layers, hot forming and flame hardening. Here, this may also in particular be methods for preheating, postheating, soaking and hot forming, for example in mechanical engineering, steel and container construction. The invention can also for example be used for drying, particularly for drying before sandblasting, welding or marking.
 For example flame heating according to DIN 8522 is a method in which a workpiece is heated in order to change its properties, for example in order to influence the resistance to deformation.
 Flame heating is also applied for preheating when welding, cutting and in related methods of metal processing. For example, during flame cutting, sheets of more than 30 mm thick made of S355 steel are preheated to 89 to 128° C. directly before the cut. In the case of carbon steels, temperatures of up to 200° C. are used in welding methods to this end, and in the case of alloy steels temperatures between 100 and 400° C. are used.
 During scarfing, for example with acetylene, a burner nozzle arrangement is directed onto a workpiece surface. As a result, clean sheet surfaces for further processing can be achieved and rust, rolling skin and scale layers can be removed simply and in an uncomplicated manner. By scarfing, in addition to metal, concrete and natural stone surfaces can also be thermally treated, in order for example to remove paintwork, coatings, oil contaminations or rubber marks and to shape surfaces.
 In the context of the presented applications, acetylene burners are often used. Compared to other fuel gases, acetylene has an exceptionally high flame temperature of more than 3,000° C., which inter alia can be traced back to the positive enthalpy of formation of the acetylene molecule (C2H2). 8,714 kJ are released for thermal use per kilogram of acetylene. These properties of acetylene are therefore of particular interest in the case of thermal heating processes, as here the heat is transferred faster from the flame to the workpiece, the higher the temperature of the burning flame. Further advantages of acetylene include high ignition speed. The thermal efficiency is better in the method mentioned, the faster the hot combustion products impact onto the workpiece. This requirement arises in particular during the heating of metallic materials with high heat dissipation, for example in the case of steel, copper and aluminium.
 In the context of the methods mentioned, multiflame burners are frequently used, that is to say burner arrangements which have burner nozzles (individual nozzles) which are supplied from a common fuel gas source. Multiflame burners of this type are illustrated in FIGS. 1A to 1C. FIG. 1A shows a conventional handheld burner, in FIG. 1B a so-called performance burner is illustrated and in FIG. 1C a lance burner is illustrated. The depicted burners have a fuel gas supply 1 as common feature, by means of which supply a gas mixture made up of acetylene and oxygen for example is supplied. Burner nozzles 3 are attached on a gas supply and holding apparatus or a burner base body 2. Working flames 4 are formed in the case of discharging fuel gas by means of the ignition of the burner nozzles 3. The burner nozzles can have control and/or adjusting apparatuses 5.
 Before the use of a corresponding burner, all individual nozzles are to be ignited manually or automatically for example with pilot flames or ignition plugs. For the manual ignition of the burner, a pilot flame is in this case guided along the burner nozzles for example or it is ensured by means of a back pressure that a flame forms at all burner nozzles. For this, the burner is for example to be held close to a correspondingly large metal sheet. The operator of a corresponding apparatus is to ensure that a flame forms at all burner nozzles (the mixture outlet points). Whilst during the manual ignition, a visual check of the ignition process is possible, this possibility is not always present during the automated operation of a corresponding burner, in which an automatic ignition also generally takes place. For automated burner operation, the so-called "propagating ignition" of all flames often causes difficulties. For example, the suitability for propagating ignition decreases if the burner is not orientated towards a workpiece or the geometry of the workpiece is unsuitable or the spacing between the burner nozzles is too large.
 In the context of this application, "propagating ignition" may be understood as meaning the transferring of a pilot flame or burner flame from one burner nozzle to the next. The further burner nozzles subsequently ignite one after the other following the first burner nozzle, that is to say ignite in a propagating manner.
 If the propagating ignition is not successful, uncombusted fuel gases can escape. If no additional safety precautions are made, fuel gases accumulate in the surroundings of the burner and a risk of explosion results.
 Against this background, there exists the requirement for multiflame burners with improved propagating ignition properties.
DISCLOSURE OF THE INVENTION
 The invention suggests a multiflame burner with burner nozzles which can be loaded with fuel gas, particularly for thermal material processing methods, a burner nozzle for a multiflame burner of this type, which can be loaded with fuel gas, and also a method for thermal material processing with the features of the respective independent patent claims.
 Preferred embodiments are the subject matter of the respective subclaims and also the following description.
 The term "fuel gas" may in the context of this application be understood to mean pure fuel gases, for example acetylene, methane, ethane, propane, butane, ethane, methylacetylene or hydrogen, but also any desired suitable gas mixtures and also mixtures which contain oxygen and fuel gas, such as for example fuel gas/oxygen/compressed air/intake air mixtures.
 According to the invention, at least one of the burner nozzles of a multiflame burner has at least one auxiliary nozzle opening arranged laterally to a main nozzle arrangement for generating a working flame. The same fuel gas flows through the auxiliary nozzle opening as flows through the main nozzle opening and the auxiliary nozzle opening is advantageously in fluid communication with the main nozzle opening and a fuel gas supply.
 By means of the provision and a suitable arrangement of at least one auxiliary nozzle arrangement, after the ignition at least one auxiliary flame is formed, the orientation of which has a directional component (vector component) in the direction of the adjacent burner nozzle which is therefore expediently orientated in the direction of a working or auxiliary flame of an adjacent burner nozzle. By means of the measures according to the invention, in this case the transferring of a flame between individual burner nozzles of a multiflame burner can be significantly improved. As a result, a complete propagating ignition of all flames of a multiflame burner can be achieved safely and reliably, if the burner head spacing and the fuel gas quantity and/or composition (for example of an acetylene burner) lies in the functional range. By means of the measures according to the invention, it is no longer necessary for the burner to be orientated directly onto a workpiece. The danger of the escaping of uncombusted fuel gases due to burners, which are not ignited in a propagated manner, and also the risk of explosion caused thereby is reduced or eliminated.
 In the context of this application, "working flame" may be understood to mean the respective main flame of a burner nozzle of a multiflame burner, which is directed onto a workpiece and for example is used for heating this workpiece. The working flame is generally either created by means of an individual nozzle, or else by means of a main nozzle arrangement, in which a central nozzle is surrounded by further nozzles arranged around the same. If, instead of a main nozzle arrangement, an individual nozzle is provided, this may be comprised in the context of the invention by the term "main nozzle arrangement".
 Accordingly, an "auxiliary flame" is the flame provided according to the invention, effected by means of the provision of at least one auxiliary nozzle opening, and orientated at least to some extent onto an adjacent nozzle. Typically, the auxiliary flames are smaller than the main or working flames on account of smaller gas quantities or volumetric flows flowing through the auxiliary nozzle openings.
 It goes without saying that the region of a "flame" is in practice geometrically not clearly delimited, so that a "working flame" and an "auxiliary flame" may also be flame regions of a corresponding overall flame. Typically, however, the primary flames, which are in each case generated at the main and the auxiliary nozzle openings for example of an acetylene burner nozzle, can be visually clearly differentiated from one another at least to some extent. The so-called stray flame forming around a primary flame generally envelops the primary flame in the form of an overall flame.
 To form auxiliary flames in the direction of the at least one adjacent burner nozzles, at least one auxiliary nozzle opening and/or at least one nozzle channel assigned to a corresponding auxiliary nozzle opening can be arranged at an angle to the main nozzle arrangement and/or a nozzle channel assigned to the same.
 With particular advantage, particularly in the case of an arrangement of a plurality of burner nozzles in a multiflame burner in series or in a burner field, at least one of the burner nozzles is provided with auxiliary nozzle openings for generating auxiliary flames in the direction of at least two adjacent burner nozzles. By means of this arrangement, an auxiliary nozzle opening, through which fuel gas flows, can following its ignition transfer a flame directly to an adjacent auxiliary nozzle opening which is not yet ignited but through which fuel gas flows. As a result, the adjacent burner nozzle is ignited as a whole and can for its part transfer the flame to at least one further burner nozzle due to the arrangement of the auxiliary nozzle openings, that is to say ignite a burner arrangement in a propagating manner.
 In order to achieve a particularly effective formation of the auxiliary flames with advantageous geometries, a multiflame burner of the type according to the invention preferably has two, three or a plurality of auxiliary nozzle openings on at least one side of the main nozzle arrangement. By means of a corresponding arrangement, overall a suitable configuration or cross-sectional geometry of a burner flame and corresponding auxiliary flames are effected. A cross-sectional geometry of this type can be set in a targeted fashion, for example on the basis of a spacing between individual burners and/or the type or the pressure of a fuel gas used, so that a particularly effective transfer of burner flames is enabled.
 As explained, a multiflame burner according to the invention is set up so that at least one of the burners is used for igniting at least one adjacent burner nozzle via at least one auxiliary flame. This can for example be achieved by suitable orientation of the auxiliary nozzle openings, the geometry thereof, but also by means of suitable spacing of the burner nozzles. On the basis of the particular configuration of the burner nozzles with auxiliary flames, it is only additionally necessary for igniting a burner arrangement to ignite a burner, for example in an automated manner, at a location, wherein a safe propagating ignition of the overall burner is ensured.
 With particular advantage, a multiflame burner according to the invention can be constructed as a handheld burner or machine burner, for example as a performance burner or lance burner, particularly for operation with acetylene as fuel gas. Lance and performance burners with linear burner arrangement in particular benefit from the measures according to the invention due to their poorer tendency to ignite in a propagating manner.
 A multiflame burner of the type mentioned has for ignition at least one burner nozzle, a manual igniting apparatus, a pilot flame, an ignition plug or a piezo igniter, as a result of which the multiflame burner is suitable in ,particular for automatic applications with non-manual ignition.
 For the features and advantages of the burner nozzle, which is likewise provided according to the invention and can be loaded with fuel gas, reference may explicitly be made to the features of the previously mentioned multiflame burner. In particular, a burner nozzle of this type, which can be loaded with fuel gas, is constructed replaceably, so that replaceable individual nozzles can be combined into a burner base body for forming a multiflame burner and as a result the flame transfer can be optimised. Also, for the advantages and advantageous fields of application of the method according to the invention, reference may be made to the previously mentioned features.
 Further advantages and configurations of the invention result from the description and the attached drawing.
 It is to be understood that the previously mentioned features and the features which are still to be mentioned in the following, can be used not only in the respectively specified combination, but also in other combinations or alone, without departing from the context of the present invention.
 The invention is schematically illustrated in the drawing on the basis of an exemplary embodiment and is described in detail in the following, with reference to the drawing.
DESCRIPTION OF THE FIGURES
 FIG. 1 shows multiflame burners according to the prior art in a schematic illustration.
 FIG. 2 shows a burner nozzle according to a particularly preferred embodiment of the invention in a perspective oblique view.
 FIG. 3 shows a burner nozzle arrangement according to a particularly preferred embodiment of the invention in a plan view from above.
 FIG. 4 schematically shows an arrangement of burner nozzles according to a particularly preferred embodiment of the invention, which are in operation, in a side view.
 As mentioned previously, the FIGS. 1A and 1C show multiflame burners according to the prior art.
 In the following figures, identical or components acting the same manner are provided with identical reference numbers. For the sake of clarity, a repeated explanation of these elements is avoided.
 FIG. 2 shows a burner nozzle according to a particularly preferred embodiment of the invention, designated as a whole with 10, which can for example be used in a multiflame burner according to the invention.
 The burner nozzle 10 has a burner nozzle head 20 and a burner nozzle base 21. If the burner nozzle 10 is a replaceable nozzle, this can be fastened with the burner nozzle base 21 in a burner base body. In the burner nozzle head 20, a main nozzle arrangement 30 is provided, which has a main nozzle opening and further nozzle openings surrounding the same in a circular manner. The main nozzle arrangement 30 is, as explained previously, set up for forming a working flame.
 In addition, the burner nozzle 10 has auxiliary nozzle openings 40 provided in addition to the main nozzle arrangement 30 for generating auxiliary flames. The auxiliary nozzle openings 40 themselves or the corresponding nozzle channels thereof can in this case be angularly offset to the orientation of the main nozzle arrangement 30, so that a targeted orientation of the auxiliary flames in the direction of adjacent burner nozzles or the flames thereof can be achieved.
 In FIG. 3, 4 burner nozzles 11, 12, 13, 14 overall are illustrated according to a particularly preferred embodiment of the invention in a plan view.
 The burner nozzles 11, 13 and 14 correspond in terms of configuration and arrangement to the auxiliary nozzle openings 40 in this case of the burner nozzle 10 from FIG. 2. The burner nozzle 12 by contrast has auxiliary nozzle openings 41 pointing perpendicularly downwards in the figure, which are orientated in the direction of a burner nozzle 14 arranged at right angles to the row of the burner nozzles 11, 12 and 13. By means of the arrangement, as is illustrated in FIG. 3, a propagating ignition or flame transfer, as is illustrated by means of the arrows 50, can be achieved with particular advantage between the individual burner nozzles 11, 12, 13 and 14. The burner nozzles 11, 12, 13 and 14 illustrated can in this case be part of a multiflame burner or a burner field of a multiflame burner. It goes without saying that the configuration illustrated in FIG. 3 can be expanded in any desired manner and, if further auxiliary nozzle openings 40, 41 are provided, a safe propagating ignition 50 can also be effected in additional directions.
 In FIG. 4, a corresponding burner nozzle arrangement in operation is illustrated schematically. A fuel gas here escapes from the burners 15 via a main nozzle arrangement and laterally auxiliary nozzle openings 40 arranged laterally thereto. As a result, the formation of a main flame or working flame 60, which can be orientated onto a workpiece, results. The primary flame of this working flame is indicated with 70. In addition to the main flame 60 or the primary flame 70 thereof, auxiliary flames 80 with corresponding primary flames 90 are illustrated in FIG. 4. The auxiliary flames 80 are orientated at least to some extent in the direction of adjacent nozzles, as a result of which the said particularly advantageous propagating ignition results.
Patent applications by LINDE AKTIENGESELLSCHAFT
Patent applications in class BURNER HAVING ELECTRICAL HEATER OR IGNITER
Patent applications in all subclasses BURNER HAVING ELECTRICAL HEATER OR IGNITER