EP0370088A1

EP0370088A1 - Radiant burner for gaseous fuel

Info

Publication number: EP0370088A1
Application number: EP89905059A
Authority: EP
Inventors: Kurt Krieger
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-05-16
Filing date: 1989-05-02
Publication date: 1990-05-30
Also published as: WO1989011621A1; US5104309A; FI900229A0; JPH02504305A; DE8817110U1; DE3816592A1

Abstract

Dans un brûleur radiant, dont la tête présente un corps incandescent en céramique comportant divers canaux intérieurs, le corps incandescent (3) est muni, à son intérieur, d'un revêtement métallique (7) qui se prolonge à l'intérieur de chacun des canaux (6) et qui est fermé, excepté aux entrées des canaux.In a radiant burner, the head of which has an incandescent ceramic body having various internal channels, the incandescent body (3) is provided, inside, with a metallic coating (7) which extends inside each of the channels (6) and which is closed, except at the channel inputs.

Description

Radiant burner for gaseous fuel

T e c h n i s c h e s G e b i e t

The invention relates to a radiant burner according to the preamble of claim 1 and to a method for producing a burner head or incandescent body for such a radiant burner.

State of the art

Radiant burners with a ceramic burner head have been known for a long time. A major problem with such burners is the susceptibility of the ceramic body to cracking. This has an unfavorable effect on the life of the burner and necessitates repair or assembly work with a corresponding expenditure of time and costs. In addition, there is a system failure in which the burners are used. Even minor cracks in the incandescent body can already lead to considerable difficulties when working the burner, because this results in undesired passages for the operating medium, which, in addition to other inconveniences, can also result in reignitions. Presentation of the invention

The object of the invention is to eliminate the disadvantages and difficulties previously observed as far as possible and to provide a radiation burner with a burner head made of ceramic or comparable material which has advantageous properties, in particular largely insensitive to the risk of cracks in the ceramic body and is safe against reignitions caused otherwise and thus also has a favorable service life. The invention also aims for an advantageous design of a radiation burner in detail. Further problems connected with all of this, with which the invention is concerned, result from the respective explanation of the indicated solution.

In the case of a radiant burner of the type specified, the invention provides that the incandescent body is provided on its inside or rear side, that is to say the side facing the housing, with a metallic covering, each of which extends into the burner ducts over part of the length thereof as Inlet areas designated areas continues and which is closed with the exception of the thus formed inlet of the burner channels.

This means that the incandescent body has an impermeable closure on the back, which extends into the burner channels. Even if cracks or breaks occur in the glow plug over the course of time, they cannot have a detrimental effect on the operating behavior of the burner, because the path for any fuel-air mixture which occurs in such cracks backwards, including the inlet areas to the channels is blocked by clothing. The dangers of conventional Burners through cracks or the like. in the incandescent body are now rendered harmless here. The burner can therefore continue to work even if cracks have occurred, so that costly repairs are avoided and the service life is extended. The prevention of re-ignition achieved applies irrespective of the burner's respective load, so that it is therefore possible to operate the burner with very reduced output, as is desirable in many cases, at least temporarily.

Depending on the intended use of the burner and the requirements placed on it, the clothing can consist of different types of metal. In addition to iron, heat-resistant stainless steel is particularly suitable.

In many cases it is sufficient if the inlet parts of the clothing only encompass the edge areas at the ends of the channels. On the other hand, it can be advantageous to let the inlet sections extend further into the burner channels, in particular up to about half the channel length or even more.

In an expedient embodiment, the inlet parts with the remaining clothing consist of one piece. Such an element can be produced in particular by deformation (e.g. pressing, punching, punching or a combination of such operations) of a plate-shaped workpiece provided as clothing, namely a sheet.

However, it is also possible to manufacture the inlet parts as separate parts from the flat clothing and to connect them to the burner head during assembly. The connection can be fixed or also detachable, be it with a positive engagement of the parts, be it non-positively, such as in particular by a press fit.

The clothing can lie directly on the incandescent body. However, depending on the requirements, an intermediate layer can also be provided between the incandescent body and the clothing, in particular made of a heat-resistant fiber fleece or of a refractory mass. This is particularly advantageous if a prefabricated incandescent body consisting of one or more parts, e.g. a ceramic plate with which clothing is put together to form the burner head. The intermediate layer can have the task of compensating for any small dimensional or shape deviations in the parts. It can also serve as a special connecting means and be composed in such a way that the parts adhere securely to one another.

The burner channels can have, at least in their part adjacent to the outer side of the incandescent body, a rotationally symmetrical cross-sectional shape with an extension, in particular with a more or less curved contour.

In a further advantageous embodiment, the burner channels each have an essentially star-shaped cross section, at least in a part adjacent to the outside of the glow body, with a central region and radial spaces extending from this and open to the outside of the glow body. The center area can be open or closed to the outside. The number of radial spaces is expediently two to six, but can also be larger.

Furthermore, the design can also advantageously be made such that the burner channels each adjoin at least one of the outside of the incandescent body Continue part in at least two sloping individual channels. It also applies here that the number of individual channels is expediently two to six or is still large.

It applies to the various designs given above that they enable the jet burner to work particularly reliably, that a favorable degree of efficiency can be achieved and that operation at high temperatures can take place, with rapid and intensive heating of the incandescent body being achievable. these statements are of particular importance.

Another advantageous feature, regardless of the other design of the radiant burner, is that the burner channels or their parts end in outside recesses of the incandescent body. These depressions can be designed in different ways. Particularly advantageously, they are designed as fields surrounded by rib-like projections of the incandescent body. Such designs have the advantage that the outlets of the burner channels are protected and adverse effects of air movements on the front of the burner are prevented or at least significantly reduced

On the side of the cladding facing away from the glow plug, when the burner is designed, a space is supplied to the fuel-air mixture, which then flows through the burner channels.

In another advantageous embodiment, on the side of the clothing facing away from the incandescent body there is a space provided for receiving at least one component of the fuel-air mixture, and there are burner ducts which are open to this space and have feed lines closed off from it for little at least another component of the fuel-air mixture assigned. The supply lines expediently extend into the burner ducts.

The medium flowing in through the feed lines takes the medium in the adjacent room with it, so that there is a nozzle or injector effect and, with intensive mixing, favorable flow conditions are achieved. Gas can in particular be supplied through the supply lines, while air flows in from the adjacent room. But it can also be the other way around.

In such a radiation burner, wherein the individual burner channels of a burner head leads ^• allocated for a medium each, there is a very vorteil¬ exemplary embodiment in that protrude either the burner channels, namely at least obligations in the part into which the Zulei¬, a have a round cross-sectional shape, in particular a circular cross-section or an oval cross-section, and the feed lines each have a polygonal cross-section, at least in their end region reaching into the burner channels. The training can also be reversed accordingly. Special cross-sectional relationships can be achieved.

With such designs, the feed lines can be supported at least with their ends on the burner channels with particular advantage. In this way, a favorable centering is achieved with additional holding of the supply lines.

As stated above, the glow body of the burner head can be produced separately from the clothing, whereupon the parts are then joined together. Furthermore, the invention provides that a suitable for the formation of the glow body on a prefabricated clothing Mass is applied, which is then solidified. Depending on the type of this mass, this can be done, for example, by drying, curing, by firing or by another process. The burner channels can be stencils, fittings or the like. mold it or create it later, provided that it is not already formed by the inlet sections on the clothing. Otherwise, a simple box-like shape can be used when applying the mass for the incandescent body, for example a sheet metal box or with parts similar to a formwork, which forms the lateral boundary all around while the mass is being applied or applied. Depending on its nature and consistency, the mass can be applied by pouring, pouring, in particular by pounding or by spraying.

The dimensions for the incandescent body include Compositions are considered that contain aluminum oxide, silicon oxide, zirconium oxide or similar substances. Materials of this type are available which are very suitable for the production of a glow body with clothing. Such modern materials, such as those used as linings in industrial furnaces or for the restoration of such linings, in particular ceramic fiber materials, are particularly suitable. There are also materials that are extremely heat-resistant, so that burners with incandescent bodies made from them can be operated at high temperatures.

Further details, features and advantages of the invention result from the following explanation of exemplary embodiments, from the associated drawing and from the claims. Brief description of the drawing

Show it:

1 shows a first embodiment of a radiant burner, partly in view, partly in section,

2 shows a part of the clad incandescent body on a larger scale, FIG. 3 is a plan view of FIG. 2,

4 shows a modified embodiment in a section corresponding approximately to FIG. 2,

5 shows another detail in section,

6 shows another embodiment of a radiant burner, partly in view, partly in section,

7 shows a location of the incandescent body of the burner according to FIG. 6 in section on a larger scale,

8 shows a section along line VIII-VIII in FIG. 7,

Flg. 9 to 11 modified versions, in each case approximately in the sections corresponding to FIG. 8,

12 shows a further embodiment of a burner channel in a top view of the outside of the incandescent body,

13 shows a section along the line XIII-XIII in FIG. 12, 14 shows a further embodiment of a burner channel in a plan view corresponding to FIG. 12,

15 shows a section along the line XV - XV in FIG. 14,

16 shows a partial top view of the outside of a glow body which is specially designed in this area,

Fig. 17 is a section along the line XVII - XVII in Figure 16 and

Fig. 18 is a partial plan view of the outside of a filament in another embodiment.

Preferred ways of carrying out the invention

The infrared radiation burner shown in FIGS. 1 to 3 has a housing 1 made of sheet metal, which encloses a space 2. A feed 5 for a fuel gas / air mixture opens into this. This is generated in a manner known in such burners and supplied via suitable fittings, so that it need not be discussed in detail.

In its front (lower in the drawing) the burner has a glow body 3 made of heat-resistant material, which is received and held in a part of the housing 1 which is offset in a shoulder 1 a, for example by flanging the edge of the housing at individual points thereof and / or with a small space provided on the circumference between the incandescent body and the housing filling refractory mass 4, which also results in a seal in these areas. The basic or, for example, square or rectangular incandescent body 3 is provided with a number of burner channels 6, which are arranged over its surface regularly or in a predetermined pattern. These burner channels 6 widen outwards, as can be seen from FIGS. 1 and 2. The course of the wall can be straight, but is expediently curved, as shown. The shape and length of the extension are chosen to best suit the requirements of the respective application, in such a way that the gas mixture jet is slowed down until, at one point in the channel, the conditions regarding the ignition speed are such that there Combustion stands.

On the inside, the incandescent body 3 is provided with an essentially plate-shaped clothing 7, which in this embodiment consists of stainless steel sheet and lies tightly on the incandescent body. It extends into the burner channels 6 with the inlet parts 8 formed from the sheet metal itself, so that it also covers the incandescent body in these areas. The inlets of the channels 6 initially have a larger diameter on this side, starting from the mixture space 2, in comparison to the narrowest channel cross section, which then decreases.

The length of the inlet sections 8 may vary depending on the circumstances. It is advantageously about half the total length L of the channels 6, but can also be smaller or larger. The cladding 7 results in a complete closure of the incandescent body 3 towards the inside, in this case towards the room 2, so that no reignitions can occur even if cracks occur in the incandescent body.

The clothing 7 can be flat at its edges, it can grip around the edges of the glow body 3 or e.g. also have upstanding bevels 7a which lie firmly against the shoulder la of the housing 1.

In the embodiment according to Figures 1 to 3, the inlet parts 8 with the clothing 7 consist of one piece. 4 shows an embodiment in which the inlet parts 8 'are separately produced parts which are inserted into holes in the clothing 7' and thereby rest on the clothing 7 'with a flange-like edge 8a. The parts 8 'can be tightly connected to the plate 7' by being pressed into the holes 9 or can also be attached to it in another suitable manner.

In the embodiments according to FIGS. 1 to 4, the material of the incandescent body 3 lies directly on the underside of the clothing 7. 5 illustrates an embodiment in which there is an intermediate layer 10 between the glow element 3 and the cladding 7. This can consist in particular of a non-woven fabric.

Another embodiment of a radiation burner is shown in FIGS. 6 to 8. In a metal housing 11 there are two rooms 12 and 13 which are separated from one another by a wall 14. A feed pipe 15 for fuel gas opens into the space 12, while a feed pipe 16 for combustion air opens into the space 13. In Bores of the partition wall 14, supply lines 17 in the form of metal tubes are firmly and tightly inserted, for example welded or soldered.

The burner, like that of the embodiment explained above, has a burner head with a glow body 3 containing burner channels 6 and a cladding 7, 8 thereon. The same or corresponding parts are designated by the same reference numerals as in Figures 1 to 3. The same goes for all of the above.

The supply lines 17 are assigned to the burner channels 6 in terms of number and distribution and each extend into the burner channel 6 by a certain amount. Their ends can be without touching the wall of the respective burner channel. They are then only held by the partition 14. It is not critical whether the axes of the feed lines 17 run exactly centrally to the longitudinal axes of the channels 6. The medium flowing out of the space 12 through the feed lines 17 pulls the medium in the space 13 with it, so that intensive mixing takes place and the combustible mixture formed continues to flow in the respective channel until it reaches the desired point for combustion.

Above, room 12 was specified as a prechamber for fuel gas and room 13 as a prechamber for combustion air. However, it can also be the other way around, such that the space 12 is supplied with air through the supply pipe 15 and the space 12 is supplied with fuel gas through the supply pipe 16. 8 shows a feed line 17 with a circular cross section in a likewise circular burner channel 6. In addition, further designs are possible, as FIGS. 9 to 11 each illustrate in sections that correspond approximately to the section according to FIG. 8. In particular, it can be the case that the dimensions of the feed lines and the burner ducts at the relevant points are selected such that the ends of the feed lines are supported on the walls of the burner ducts or the inlet parts of the clothing.

FIG. 9 shows a feed line 19 in the form of a tube with a square cross section and FIG. 10 shows a feed line 20 in the form of a tube with a triangular cross section, in each case with a burner channel 6 with a circular cross section. In the embodiment according to FIG. 11, the burner channel 6 'and correspondingly the inlet section 18 of the clothing have a square cross section with a feed line 17 with a circular cross section.

Regardless of the training in detail, depending on the circumstances and requirements, the burner can also be equipped with a grid, network or the like. be provided, which is arranged in front of the incandescent body. In FIGS. 1 and 6, such a grid is indicated by dash-dotted lines and designated by the number 30. *

In the embodiment shown in FIGS. 12 and 13 of a burner channel, designated as a whole by the number 26, this has a substantially star-shaped cross section following a cylindrical part 25 with a central region 27 and radial groove 28 which extends from this and is approximately groove-shaped and which extends to the outside of the Glow bodies 23 are open. These radial spaces 28 have boundary surfaces 29 which run obliquely to the axis of the burner channel 26 and form the base of the groove and have an approximately rectangular cross section, as can be seen from the figures. The cross-sectional shape can also be chosen differently.

The center area 27 can be open to the outside of the incandescent body 23 or else closed. The latter is indicated by dash-dotted lines in FIG. 13 by a part 24 of the incandescent body 23 left at this point. An inserted closure part can also be provided at this point.

In the embodiment according to FIGS. 14 and 15, effective parts of the burner channels 36 are formed by individual channels 38 in the glow body 33, which run obliquely to the axis of the burner channel. Deviating from the design shown, a central channel part 37 can also extend to the outside of the incandescent body 33, so that it opens to the outside thereof.

In FIGS. 12 and 13 or 14 and 15 there are four radial spaces 28 and four individual channels 38, respectively. Their number can also be chosen differently. Both an even and an odd number of such radial spaces or individual channels can be considered.

FIGS. 16 and 17 show an embodiment of an incandescent body 33 which is of fundamental importance irrespective of the type, design and arrangement of the burner channels. The burner channels or their parts 38 here (approximately corresponding to an embodiment according to FIGS. 14 and 15) end in recesses 21 the outside or in the end face of the incandescent body 33. This provides effective protection against undesired influences from external air currents. In the embodiment shown, the depressions 21 form fields which are surrounded in a frame-like manner by rib-like projections 22 of the incandescent body 33.

18 shows a corresponding embodiment with depressions 21 in the end face of the incandescent body 3, burner channels 6 being present here which correspond approximately to the embodiment according to FIGS. 1 to 4 or 6 to 11.

All the features mentioned in the above description or shown in the drawing, if the known prior art permits, should be regarded as falling within the scope of the invention, either alone or in combinations.

Claims

Patent claims

1. Radiant burner, which can be operated with a mixture of gaseous or vaporous fuel and air and contains a housing and a burner head with a single burner channel, in particular with an expanding shape, incandescent body made of ceramic or similar material, thereby characterized in that the incandescent body (3) is provided on its inside with metallic cladding (7, 7 ') which extends into the burner channels (6, 6') over part of their length with inlet sections (8, 8 ', 18) continues and is closed with the exception of the channel inlets.

2. Radiant burner according to claim 1, characterized in that the inlet sections (8) with the rest of the clothing (7) consist of one piece.

3. Radiant burner according to claims 1 and 2, characterized in that the inlet sections (7) are produced by deforming a plate-shaped workpiece provided as clothing (7).

4. Radiant burner according to claim 1, characterized in that the inlet sections (8 ') are made separately from the clothing (7) and are connected to them.

5. Radiant burner according to one of claims 1 to 4, characterized in that the inlet sections (8) extend at least up to half the total length (L) of the burner channels (6).

6. Radiant burner according to one of claims 1 to 5, characterized in that an intermediate layer (10) is provided between the incandescent body (3) and the clothing (7).

7. Radiant burner with an incandescent body and burner channels located therein, in particular according to one of claims 1 to 6, characterized in that the burner channels (26, 36) at least in one of the outside of the incandescent body (23) adjacent part each have a substantially star-shaped cross section have a central region (27) and radial spaces (28) open to the outside of the incandescent body (23).

8. Radiant burner according to claim 7, characterized in that the center region (27) to the outside of the incandescent body (23) is open.

9. Radiant burner according to claim 7, characterized in that the center region (27) to the outside of the incandescent body (23) is closed.

10. Radiant burner with an incandescent body and burner channels located therein, in particular according to one of claims 1 to 6, characterized in that the burner channels (26, 36) at least in one part of the outside of the incandescent body (33) adjacent part each have at least two inclined individual have channels (38).

11. Radiant burner with an incandescent body and burner channels located therein, in particular according to one of claims 1 to 10, characterized in that the burner channels (6, 6 ', 26, 36) or their parts

(28, 38) end in depressions (21) of the incandescent body (3, 23, 33).

12. Radiant burner according to claim 11, characterized gekenn¬ characterized in that the depressions (21) as from rib-like projections (22) of the incandescent body (3, 23, 33) are formed fields.

13. Radiant burner according to one of claims 1 to 12, characterized in that the clothing (7) with its side facing away from the incandescent body (3) forms the limitation of a space (2) for the fuel-air mixture.

14. Radiant burner according to one of claims 1 to 12, characterized in that on the incandescent body (3) ^' facing away from the clothing (7) is provided for receiving at least one component of the Brennstσff-Luft Ge Ge space (13) and to this space (13) open burner channels (6) each have a feed line (17) for another component of the fuel-air mixture is assigned. ,

15. Radiant burner according to claim 14, characterized gekenn¬ characterized in that the feed lines (17) extend into the burner channels (6).

16. Radiant burner according to claim 15, characterized gekenn¬ characterized in that the burner channels (6) at least in that part into which the leads (19, 20) protrude, have a round cross-sectional shape and the leads (19, 20) at least in their the part protruding into the burner channels (6) has a polygonal cross section.

17. Radiant burner according to claim 15, characterized in that the burner channels (6 ') have a polygonal cross-section at least in the part into which the feed lines (17) protrude and the feed lines (17) at least in their the burner channels (6 ¹ ) projecting part have a round cross-sectional shape.

18. Radiant burner according to one of claims 16 and 17, characterized in that the feed lines (17, 19, 20) on the burner channels (6) or inlet sections (8) belonging to them are supported.

19. A method for producing a burner head for a radiant burner according to one of claims 1 to 18, characterized in that a mass provided for the formation of the incandescent body (3) is applied to a prefabricated clothing (7 or 7, 8), which is then solidified.

20. The method according to claim 19, characterized in that the mass is applied by stamping.

21. The method according to claim 19, characterized in that the mass is applied by spraying.