DE69322622T2 - POROUS METAL FIBER PANEL - Google Patents

Abstract

The invention relates to a porous metal fiber plate (1), in which a regular pattern of holes (2) has been made which occupy an overall free passage area of 5 % to 35 % of the total surface area of the plate, while each hole (2) has a surface area of between 0.03 mm<2> and 10 mm<2>. The plate is suitable for use as a membrane in a gas burner device. The invention covers also a gas burner device in which such a porous metal fiber membrane is mounted.

Description

FIELD OF INVENTION

The invention relates to a porous metal fiber plate. Such plates, in which the fibers are sintered together, are used, among other things, as filter media.

It is further known from European Patent 0 157 432 to use these fiber networks as a membrane for radiant surface combustion burners for gas mixtures, as long as steel fibers containing Cr and Al are used to make them resistant to high temperatures.

Since the porosity of these non-woven steel fiber networks, fiber mats or sintered fiber boards is not always completely homogeneous, a uniform cross-gas flow over the entire surface of the board cannot always be guaranteed. This has proven to be a disadvantage for a number of applications, e.g. for burner membranes and for the gas-permeable carrier plates for fluidized bed treatments, where a controlled uniform flow, in conjunction with a low pressure drop across the thickness of the board, is desired.

It is an object of the invention to avoid this disadvantage of the known gas-permeable metal fiber plates and thus to provide plates with a controlled uniform gas flow. According to the invention, this object is achieved by a method according to claim 1.

In a plate according to such a method, the gas flow is mainly driven through the holes. This feature is advantageous, among other things, in terms of achieving a low pressure drop through the plate.

Insofar as these plates must be used at very high temperatures, it is necessary that the metal fibers used can withstand these temperatures. The equivalent fiber diameters can range between about 8 µm and 150 µm. By an equivalent fiber diameter is meant here the diameter of a fictitious, completely cylindrical fiber, the cross-sectional area of which corresponds to the average cross-sectional area of a real fiber that is not completely circular or not circular at all. The thickness of the plate is preferably between 0.8 mm and 4 mm, and the plate is stiff and strong enough to withstand the selected pressure drops at the desired porosities. For example, plate thicknesses of 1, 2 and 3 mm are suitable. The porous plate therefore does not require any extra support near its bottom surface or its top surface (e.g. with a steel plate). This leaves the bottom and top surfaces freely accessible.

It is another object of the invention to provide a gas burner device comprising a housing with supply means for the gas to be burned, a distribution member for the gas flow and a porous metal fiber plate as a burner membrane, which enables a controllable and uniform gas flow to the burner membrane exit surface and as a result a uniform combustion process over the entire burner surface and with a low pressure drop in the gas flow passing through the membrane.

As a result, a durable burner membrane is provided wherein no particular surface areas deteriorate prematurely due to overloading or overheating relative to other areas due to inhomogeneities in the porosity, thereby causing uncontrollable preferential gas flow paths and combustion areas.

The method of the invention enables the creation of a porous metal fiber plate which can be used as a burner membrane over It can be used over an extremely wide power range and is therefore suitable for both surface radiation and blue flame types.

As a result, the invention enables the creation of burner membrane plates that offer significantly low CO and NOX emissions and high yields.

As a further result, the invention enables the creation of a gas burner with fewer constraints regarding pre-filtration of the incoming gas stream.

The provision of a gas combustion device with a lower risk of resonances occurring in the gas flow and thus avoiding whistling effects during operation is to be considered as a further object of the invention.

On the basis of several embodiments, further details are explained below. Additional solutions according to the invention for particular or partial problems or objectives and the characteristics of these solutions as well as the advantages achieved thereby will also be explained.

Fig. 1 is a sketch of a porous plate with circular holes according to the invention.

Fig. 2 shows a possible way of installing this plate in a housing with supply means for the gas as well as conveying and flow means for this through the plate.

Fig. 3 shows schematically a tubular device for the passage of the gas flow.

Figures 4 to 7 relate to plan views of several patterns of transverse passages to be provided in the porous plates, which do not fall within the scope of the independent claim.

Fig. 8 shows a cross-section of a gas burner device according to the invention, in which an acoustic damping layer is attached between the burner membrane and the distribution component.

Fig. 9 shows a cross-section of a gas burner device, incorporating a number of sound-damping layers, possibly together with empty spaces.

The porous metal fiber plate 1 according to Fig. 1 has holes 2 spaced apart from each other at regular intervals p (hole spacing). These holes are preferably of cylindrical shape and in particular circular-cylindrical. Preferably, the area of each hole 2 is the same and is between 0.03 and 3 mm², although more preferably between 0.4 and 1.5 mm or between 0.5 and 0.8 mm. As will be seen below, these dimensions are to be chosen depending, among other things, on the thickness of the plate 1, its porosity and the intended use. If the hole 2 thus has a circular cross-section, the diameter of each circle is 0.8 mm for a surface of approximately 0.5 mm. The holes 2 are preferably produced by a punching process, since this ensures a smooth cylinder wall. If so desired, holes can also be punched with triangular, square, rectangular or other shapes. The holes can also be created with laser beams. In principle, very small holes with a diameter of at least 0.2 mm are possible for thin plates.

Figs. 4 to 7 illustrate other preferred forms of passages: slots of various shapes and their regular distribution over the plate surface. Two examples of a suitable regular pattern of adjacent rectangular slots 9 are shown in Fig. 4 (right side and left side respectively). Circular passages 2 and rectangular slots 9 may alternate over the surface as shown in Fig. 5. Similarly, oval or elliptical Slots 11 alternate with circular holes 2, as shown in Fig. 7. A pattern of cross-shaped slots 10 is also possible, as illustrated in Fig. 6. A large number of regular distributions of passages with different shapes are conceivable with a view to, among other things, minimizing or avoiding any whistling effect in the gas flow, as will be explained further.

Each of the slots 9, 10, 11 should preferably have a surface area of between 1 and 10 mm². Rectangular or substantially rectangular slots have a slot width "w" of between 0.3 mm and 2 mm and a length "l" of between 3 mm and 20 mm. Preferably, the relationships 0.5 mm ≤ w ≤ 1 mm and 5 mm ≤ l ≤ 10 mm apply. In any case, in a plate with rectangular slots 9 according to, for example, Fig. 4 or 5, the total free passage area takes up 20% to 30% of the total surface area of the plate.

The distance p between adjacent holes 2 is chosen so that their total surface area occupies 5% to 25% of the total surface area of the plate and preferably 8% to 16%. Values of 10%, 12% and 15% are appropriate. In order to ensure a uniform flow over the surface, the successive holes are preferably arranged in a pattern of adjacent equilateral triangles, in which each hole 2 occupies one corner of the triangle.

The porosity of the plate (between the holes 2) is always between 60% and 95%, but preferably between 78% and 88%. The plate surfaces can be flat, have a (highly embossed) relief shape or be curved or corrugated, for example.

The metal fibres that can be used to produce the porous panels and the production of the panels themselves, and especially those that are resistant to very high temperatures, are carried out in the same European patent application 390.255. Stainless steel fibers are generally suitable. For high-temperature applications, e.g. in gas burners, steel fibers containing Cr and Al, preferably those containing a small amount of yttrium, should be used.

As shown in Fig. 2, the porous plate 1 according to the invention can be installed in a normal manner in a housing 3 with a supply means 4 for the gas. If this device is intended to function as a gas burner, a combustible gas mixture (e.g. natural gas/air) can be supplied. The device thus formed can also have a distribution device 5 for the incoming gas flow. Normally this is a plate with suitable holes or passages arranged in it so that a uniform gas flow with a suitable pressure reaches the inlet side of the porous plate 1. The surface area of the free passages in the distribution plate 5 can be between 2% and 10%. In the case of a cylindrical burner (Fig. 3) the distribution plate 5 also serves as a supporting element for the end plate 8. The distribution element 5 may possibly be corrugated and may also act to neutralize possible sound resonances in the gas flow or as a flame arrester or barrier should they flash back into the gas inlet side of the plate 1, e.g. as a result of damage (cracks) in the burner plate. If desired, the holes may have a conical inlet 6 and a cylindrical outlet 7 or vice versa (inverted plate) a cylindrical inlet and a conical outlet.

A distribution component 5 is preferably also provided for the gas supply together with an end plate 8 in the cylindrical device according to Fig. 3. Due to the flexibility of the membrane plate 1 with hole pattern 2, cylinders of relatively small diameters can be bent from flat plates.

It has been found that with certain shapes of burner housings and built-in structures in the spaces to be heated (e.g. boilers), resonance can occur at relatively high powers, e.g. over 1000 kWJm². It also appears that excess air in the gas mixture supply can have an influence on the tendency to resonance together with whether the gas is either drawn (sucked) through the membrane or blown through it. Finally, the pattern of holes used in the membrane itself can also play a role in the resonance phenomenon.

The resonance phenomenon is presumably related to the high pressure gradient of the gas mixture between the relatively cold lower surface (inlet side) of the burner diaphragm and the very hot upper surface (exit side: combustion surface). By changing the flow passage variables, such as excess air and gas mixture flow rate, an oscillation phenomenon probably occurs between the flame front (i.e. the level of the flame bases) and the gas mixture flowing into the holes. The flame tongues can therefore dance up and down over the burner surface or even oscillate with their flame bases between a position in (or even under) the holes and a position above the holes (above the combustion surface). This can be accompanied by annoying whistling noises in the range of 1000 to 1500 Hz. This disadvantage can also be encountered when a burner is changed from a blow-gas to a suction gas system.

As previously mentioned, it is an object of the invention to eliminate this disadvantage and to make the occurrence of whistling noises less critical. However, the measure taken should not reduce any of the other advantages of the perforated burner membrane concept. In particular, the measure should not lead to a drastic increase in the total pressure drop across the burner or (local) destabilization of the flame front.

The solution according to the invention consists in providing a gas burner device comprising a housing with the following components positioned successively downstream: feeding means for the gas to be burned, a distribution component, at least one acoustic silencer permeable to gas, and a porous plate as burner membrane provided with a regular pattern of holes which together represent 5% to 35% of the surface of the plate, each hole having a surface area of between 0.03 mm² and 10 mm².

Details are explained on the basis of a number of embodiments, with reference to Figs. 8 and 9. The embodiments are to be understood as examples only.

The gas burner device according to Fig. 8 comprises a housing 16 with the following components positioned sequentially downstream of each other: a supply line 15 for the gas mixture and a distribution component 5 in the form of a perforated metal plate lying against the bent edge 22 of the supply line 15. The housing 16 is attached to the supply line by a weld 17. The distribution plate 5 is, for example, 0.4 mm thick and provided with holes 18 each having a diameter of 0.4 mm. The holes or channels 18 may be positioned at the corners of a pattern of adjacent equilateral triangles with a triangle side (i.e. distance between the holes) of 1.25 mm. This means a free passage surface of the plate 5 of approximately 10%. Depending on the circumstances this free surface could equally well be between 5% and 20%. Below 5% the pressure drop becomes too high at high gas flow velocities; over 20% the distribution effect for the gas mixture becomes insufficient at low flow velocities.

Against the outlet side of the distribution component 5 there is a welded wire net 13 made of stainless steel with a wire diameter of, for example, 0.125 mm and a gas permeability of 48 mesh (meshes per inch). Depending on the circumstances, a permeability of between 30 mesh and 60 mesh can be selected. Two or more nets 13 can also be stacked one on top of the other, preferably of different permeabilities.

Downstream of the welded wire mesh (or meshes) 13, which act as acoustic sound-damping layer(s), is the porous membrane plate 1, which is provided with a regular pattern of holes 12. This porous plate is again preferably a sintered metal fibre plate in which the fibres are heat-resistant, i.e. resistant to the high burner temperatures encountered during operation, and resistant to thermal shocks. The fibres are therefore preferably steel fibres with a suitable Cr and Al content: e.g. FeCr alloy fibres, as previously described.

For example, the plate 1 is 2 mm thick and has a porosity of 80.5% between the holes. The fiber diameter in Example 2 below was 22 µm, and the diameter of the cylindrical punched holes was 0.8 mm, while the distance between the centers of the holes (i.e., the pitch) was 1.5 mm. The plate 1 is fixed to the housing 16 with a ceramic mat 14 inserted between the two.

In order to minimize resonance with particular gas flow profiles in specially shaped burners for situations in which the gas mixture is drawn (sucked) and/or for particular design parameters relating to the combustion chamber to be heated, it may be considered to provide a gap 23 or 24 between the acoustic damping layer 13 and the distribution member 5 and/or the membrane 1, as shown for example in Fig. 9. In this way, various embodiments of the device are created. The device may, for example, comprise a damping layer 13 which is in surface contact with the distribution member 5. In another embodiment, the layer 13 may be in surface contact with both the member 5 and the porous plate 1.

Another possibility is to manufacture the sound-damping layer 13 as a laminate consisting of two wire nets 25 and 26 with a porous mat inserted between them. If so desired, the porosity and hence also the pressure drop across this laminate can be changed under the influence of the gas pressure of the incoming mixture or via external working means (not shown). The porous mat 27 can, for example, be an elastic mat of fibers, e.g. steel wool. In addition to a stronger distribution effect on the mixture, this transverse compression or relaxation of the laminate can reduce the pressure drop across the membrane 1 at high flow velocities, so that again the danger of resonance becomes less critical.

According to another embodiment, the soundproofing layer 13 can consist entirely or partially of a porous mass of fibers 27. If so desired, this mass can fill the entire space between the plate 1 and the structural element 5. Preferably, mineral fibers (e.g. rock wool or steel wool) are to be used.

Finally, the porous plate 1 may also contain a laminate of wire nets sintered together. Woven or knitted wire nets made of heat-resistant wires may be used for this purpose. A suitable laminate structure is described in U.S. Patent 3,780,872. On the whole, these laminates are stiffer than those made from sintered fiber webs. Therefore, they are preferably mounted in flat burners. A pattern of holes is of course also punched through these laminates, as described above.

If the gas burner devices are only designed to operate at relatively low powers or if the tendency to resonance does not have to be avoided per se, then sintered porous plates 1 as such - made of chips or cut fibers or even of wire mesh, as described above - can also be used. In this case, a sound-absorbing layer 2 is not required and embodiments corresponding to or analogous to those described in Belgian patent application 09200209 can be used. Instead of FeCr alloy fibers, ceramic fibers or wires can also be used.

EXAMPLE 1

A flat sintered porous metal fiber plate 1 made according to the invention and having the properties given below can be used as a membrane for a gas burner device. The properties and advantages of this concept with respect to previously offered burner membranes are explained below.

The steel fibres to be used are resistant to high temperatures and for this purpose contain, for example, in wt.%, 15 to 22% Cr, 4 to 5.2% Al, 0.05 to 0.4% Y, 0.2 to 0.4% Si and a maximum of 0.03% C. They have a diameter of between 8 and 35 µm, for example approximately 22 µm. The fibres can be obtained by a bundle drawing technique, as known for example from US patent 3,379,000 and as mentioned in US patent 4,094,673. They are processed into a non-woven fibre web according to a process or similar to the process known from US patents 3,469,297 or 3,127,668. Thereafter, these webs are compacted by pressing and sintering into a porous plate 1 with a porosity of between 78% and 88%. Porosities of 80.5%, 83% and 85.5% are very common.

It is also possible to use thicker metal fibers as heat-resistant fibers in the porous plate, e.g. fibers with equivalent diameters of between 35 and 150 µm consisting of wire chips or sections from a plate of the desired heat-resistant alloy (e.g. FeCr alloy). These fibers look quite like steel wool and can be made by a chipping process, such as that disclosed in U.S. Patent 4,930,199.

This porous plate 1 is now placed in a mould and provided with a suitable punching device (punch with punch pins) with a regular pattern of perfectly definite circular cylindrical passages or holes 2 with a diameter of, for example, 0.8 mm. With a distance of 2 mm between each pair of adjacent holes, a free surface of almost 15% is obtained. Compared to a plate without holes, this formation increases flexibility and at the same time facilitates the process of forming, for example, into cylinders. The holes also form barriers against the tearing or propagation of cracks that can form in the membrane plate as a result of the fluctuating heat load during operation. If so desired, the pattern of holes can be supplemented by a waffle pattern as described in EP 390.255.

Whenever holes are to be punched in a solid steel plate, the thickness of the plate must always be thinner than the diameter of the holes. Surprisingly, however, it has been found that this is not necessary for punching holes in the porous plates according to the invention. Therefore, there is a wide range of choice for the ratio of plate thickness to the diameter or dimension of the holes or passages.

The great advantages of the inventive idea, however, appear when the gas mixture to be burned passes through the porous membrane plate 1. In fact, the gas mixture now flows mainly through the holes 2, which is why the pressure drop across the membrane 1 is considerably lower (than for plates without holes) for a given flow rate, or whereby higher flow rates - and consequently higher heat outputs or powers - can be achieved for a given pressure drop value. The power range can now be chosen between 150 and 900 kW/m² for radiant surface combustion and increased to that of a blue flame surface burner with an output or power of up to 4000 kW/m², depending on factors such as the excess air in the gas mixture with respect to a stoichiometric gas combustion mixture.

The porosity of the plate 1 results in a small part of the gas always penetrating through the pores between the holes 2 to the hot exit surface. As explained below, this greatly promotes uniform and stable combustion over a wide load or power range. Particularly at higher flow rates, the part of the gas penetrating through the plate between the holes increases proportionally. It is now precisely at these higher flow rates (and consequently higher powers, if the percentage of excess air in the gas mixture remains the same) that the tendency to produce the blue The burning of the gas on the surface of the plate between the holes 2 remains, as it was, a stable (blue) flame front over the entire plate surface and prevents this front (or the blue flame tongues within it) from being blown away from the plate surface. The tongue-shaped flames above each hole remain, as before, with their bases - or roots - anchored to the plate surface.

The largely horizontal orientation of the fibers within the porous plate also promotes the insulating effect of the membrane. In fact, the heat conduction runs mainly in the outside surface (radiating side) of the plate and much less in the depth (through the thickness) of the plate. In addition, there is the continuous uniform cooling effect of the cold gas supply in direct contact with the layer of fibers on the gas inlet side. On the other hand, this uniform heat distribution at the level of the plate surface promotes the uniform combustion of the gas layer and a stable combustion state over a wide load or power range on the output side of the plate between the successive holes 2. With a porous membrane layer 1 attached on its gas inlet side, for example, to a carrier steel plate and where the porous layer together with the carrier plate have the same pattern of holes, this insulating effect will be overall less and the achievable powers will be lower. On the other hand, in another embodiment, ie a porous membrane without holes attached to a gas distribution plate support with a regular pattern of many small holes (e.g. hole diameter of 0.3 mm and pitch or center-to-center distance of adjacent holes of 1.25 mm), the achievable gas flow rate for a given pressure drop remains more limited than with the plate according to the invention. In addition, with this approach order, the high performances per burner surface unit cannot be achieved.

Another advantage over the known plate membranes without holes relates to the fact that it is now much less necessary - if at all - to pre-filter the gas to be supplied, since it flows mainly through the larger passages (holes) 2 and only to a very limited extent through the small pores in the plate 1. The membrane plates according to the invention also have to be cleaned with a backflow much less frequently than was the case with porous plates without holes or passages.

The plate thickness, its porosity and the dimensions of the passages or holes must of course all be coordinated so that no backflow to the gas inlet side occurs for any burner condition.

In a combustion test, the following observations were made for a sintered fiberboard 1 made of the known FECRALLOY fibers with a diameter of 22 µm. The board was 2 mm thick, had a porosity of 80.5% and was installed in a gas burner device of the type illustrated in Fig. 2. A pattern of holes was punched in the membrane 1 as shown in Fig. 2: the diameter of the cylinder holes was 0.8 mm and there was a regular geometric pattern of holes with a pitch p = 2 mm in a regular grid of adjacent equilateral triangles. The distribution plate 5 (0.4 mm thick) was located at a distance of 5 mm from the plate 1 and was provided with holes of 0.4 mm diameter and with their pitch of 1.5 mm. This gave a free passage surface of 6.5%. There were no noise resonances or whistling noises during operation.

The pressure drop in the gas mixture through the plate (mbar) grows slightly faster than linearly with the power received (kW/m²). At a pressure drop of 0.05 mbar, an output of 150 kW/m² was determined, and at a pressure drop of 3 mbar, an output of 3500 kW/m² was achieved. The gas mixture consisted of 8.1% natural gas and 91.9% air. Natural gas with a relatively low calorific value of 10 kWh/Nm³ was used, and 30% excess air was added.

A radiant surface burner condition was observed up to about 800 kW/m². At higher powers, combustion changed to a blue flame mode. The temperature of the membrane surface (gas outlet side) increased to approximately 850ºC at about 700 kW/m² and gradually decreased to approximately 600ºC when moving to higher powers (blue flame mode). The membrane temperature on the gas inlet side remained below 150ºC and even decreased to below 100ºC in the blue flame mode. The measured NOX emission (ppm) increased gradually over the entire power range up to 2000 kW/m². However, it was only about 10 ppm at 700 kW/m² and stabilized at about 15 to 20 ppm for powers at 2000 kW/m² and above. The measured NOX values are actually the data reduced to their value at 0.002% in the combustion gases. These very low NOx values can probably be explained by the fact that the flame tongues above the holes remain small, so that the temperature in their cores remains relatively low. The CO content was close to zero over the entire power range.

In conclusion, it was therefore found that for burner applications, the invention provides for the first time the idea of a porous plate that can be used over an enormously wide power range and is therefore suitable for both the surface radiation and blue flame types. In addition, the idea offers significantly low CO and NOX emissions and also offers high yields.

EXAMPLE 2

In the embodiment of Fig. 8, the porous plate 1 is in surface contact with the 48 mesh wire mesh 13. A gas mixture of natural gas and air was passed through the compact combination of this wire mesh 13 held together between the 2 mm thick porous plate 1 and the distribution element 5 with a free passage surface of 10% (both described above) in the housing 16. The dimension of the square burner surface was 150 mm x 150 mm. Various proportions of excess air were used (1.1 to 1.3) and the flow rates were increased so that powers in the range of 500 kW/m² to 5000 kW/m² were developed.

In Table 1 below, the resonance results are given in column [1 + 2 + 3]. For comparison, the combustion tests in the table are repeated for designs with a combination of only plate 1 and distribution component 5: column [1 + 3] and for the design without wire mesh 13 and without plate 5: column [1]. The minus sign in the table applies to the desired absence of whistling noises during combustion, while the plus sign indicates the occurrence of an annoying whistling noise. Whistling noises also indicate vibration of the flame bases 20 in the holes 12, as indicated by an arrow 21. TABLE 1

We can deduce from the table that a smaller excess air (1, 1) leads to resonance more easily than a larger excess air (1, 2 or 1,3). In addition, one can see that the beneficial effect of the wire mesh 13 is particularly evident at higher power loads (over 1000 kW/m²).

Claims (19)

1. A method of manufacturing a sintered porous metal fiber board (1) within a wide range of board thicknesses and allowing a uniform transverse gas flow, which comprises creating therein a regular pattern of transverse holes or passages (2) of a fully defined cylindrical dimension, occupying a total free passage area of 5% to 35% of the total top surface area of the board, each hole (2) having a surface area of between 0.03 mm² and 10 mm², and comprising the steps of arranging the board (1) in a mold and creating the transverse passages by means of a die with punches of the appropriate dimension penetrating the board. 2. A method according to claim 1, wherein the plate has a thickness of between 0.8 mm and 4 mm. 3. Method according to claim 1, wherein the holes (2) have a cylindrical circular shape with a surface area of between 0.03 mm² and 3 mm². 4. Method according to claim 1, wherein the passages are slots (9 to 11) each having a surface area of between 1 and 10 mm². 5. Method according to claim 1, wherein both slots (9, 11) and circular openings (2) are present. 6. The method of claim 1, wherein a porosity between successive passages is between 60% and 95%. 7. The method of claim 6, wherein the porosity is between 78% and 88%. 8. A method according to claim 1, wherein the metal fibers are resistant to high temperatures and have an equivalent diameter of between 8 and 150 µm. 9. The method of claim 8, wherein the metal fibers are steel fibers containing aluminum and chromium. 10. A method according to claim 3, wherein the holes have a surface area of between 0.5 and 0.8 mm². 11. A method according to claim 3, wherein the free transmission surface area is between 8% and 16%. 12. A method according to claim 11, wherein the successive holes (2) are arranged in a pattern of simultaneous triangles, wherein each hole (2) contains a vertex of the triangle. 13. A method according to claim 4, wherein the slots are substantially rectangular with a width "w" of between 0.4 and 2 mm and a length "1" of between 3 and 20 mm. 14. The method of claim 13, wherein the slots have a width 0.5 mm ≤ w ≤ 1 mm and a length 5 mm ≤ l ≤ 10 mm . 15. A method according to claim 13 or 14, wherein the total free passage area occupies 20% to 30% of the total top surface area of the plate. 16. Gas burner device comprising a housing (3) with feed means (4) for the gas to be burned, a distribution component (5) for the gas and a porous plate (1) produced according to claim 1 as a burner membrane. 17. Gas burner device according to claim 16, which has a housing with the following components, positioned one after the other downstream of each other: supply means (15) for the gas to be burned, a distribution component (5), at least one acoustic sound-damping layer (13) which is permeable to gases, and a porous plate (1) as a burner membrane. 18. Device according to claim 17, in which the acoustic sound-damping layer (13) contains at least one wire mesh. 19. Device according to claim 17, in which the sound-damping layer (13) consists either entirely or partially of a porous mass of fibers (27).