Anti-deflagration and anti-explosion surface combustion gas burner

Abstract

The invention relates to an anti-deflagration and anti-explosion surface combustion gas burner (1). The burner is characterized in that it comprises a burner body (2) perforated by a series of apertures (21), each aperture extending through a rim (22), these apertures (21) being arranged in rows (24) of aligned apertures (21), and a gas distributor (5) comprising a distributor body (50) equipped with a plurality of longitudinal gas distribution branches (52), each branch (52) is perforated by a series of apertures surrounded by a rim (59). Furthermore, the distributor body (50) is located inside the burner body (2) such that each orifice of the distributor body (50) is coaxial with the orifice (21) of the burner body (2) such that air and gas mix only at the rim (22) of the burner body (2) when the burner body (2) is coupled to an air supply and the distributor body (50) is coupled to a gas supply.

Description

Technical Field

[0001] The present invention relates to a surface combustion gas burner, in particular a hydrogen burner, which is particularly suitable for use in domestic or industrial heating devices to heat a fluid circulating in an exchanger. Background Art

[0002] There are two main generations of gas burners, namely atmospheric burners and fan burners.

[0003] In atmospheric burners, pressurized gas is discharged through a nozzle and passes through a convergent-divergent device to create a gas flow. The disadvantage of this type of burner is that it emits pollutants into the atmosphere.

[0004] Among fan burners, air / gas premix burners or “premix” burners allow full control of the premixing of gas and air (see, for example, the burner described in document WO2014006103). As a result, pollutant emissions are significantly reduced.

[0005] However, in the case of a premix burner, the combustion takes place on the outer surface of the burner. In order to avoid rapid burner aging due to the reddening of the outer cover (which would occur if the flame was too close to the outer cover surface), such a premix burner has a power variation range of about 1 to 3, and even a maximum of 1 to 10 if the outer cover is made of high temperature resistant material or includes a specially developed design (such as the burner described in document WO2014006103).

[0006] Furthermore, during operation of such air / gas premix burners, the flow rate of the air and gas mixture must be varied to avoid flame extinguishing due to excessive flow and, conversely, to avoid flame returning to the burner due to insufficient flow, thereby causing flashback.

[0007] Such a flashback may lead in particular to deflagration or even explosion.

[0008] Therefore, for a given burner, the adjustment range of its power is adjusted by its maximum flow rate and minimum flow rate, the maximum flow rate corresponds to a gas outlet velocity less than the flame extinction, and the minimum flow rate corresponds to a gas outlet velocity greater than the flashback velocity.

[0009] Furthermore, these two limits of the speed of the air and gas mixture are related to the propagation speed of the flame of the gas considered, in other words, to the type of gas. Therefore, the same air / gas premix burner will provide different operating ranges depending on the type of gas used and its propagation speed.

[0010] For example, the average propagation speed of natural gas is 0.37 m / s, while the average propagation speed of hydrogen is about 2.6 m / s, which is nearly seven times faster.

[0011] Therefore, prior art surface combustion burners are not well suited for use with hydrogen if it is desired to be able to use such burners over a wide power range.

[0012] However, to comply with environmental and ecological standards, hydrogen can be a beneficial alternative fuel for feeding these burners. Summary of the invention

[0013] It is therefore an object of the present invention to provide a surface combustion burner which can be operated in particular with hydrogen and which is reliable, ie avoids flashback phenomena and the associated risks, and which can be used over a wide power range.

[0014] To this end, the present invention relates to a deflagration and explosion-proof surface combustion gas burner.

[0015] According to the present invention, the burner comprises a burner body made of metal or refractory material and a gas distributor, the burner body defining an internal cavity connectable to an air supply source and having an outer surface and an inner surface, the burner body being perforated by a series of orifices, each orifice extending through an edge, the edge protruding from the outer surface and the center axis of the edge being perpendicular to the outer surface, the orifices being arranged in several rows of aligned orifices, the gas distributor comprising a distributor body, the distributor body defining a housing connectable to a gas supply source, the distributor body comprising a plurality of longitudinal gas distribution branches, each branch comprising two longitudinal walls spaced apart from each other to define a longitudinal laminar gas distribution space between each other, the longitudinal laminar gas distribution space leading to the housing at its inner longitudinal end, the two walls of each branch being connected to form an outer longitudinal edge, a closed front end and a closed rear end of the branch, each branch being perforated by a series of orifices aligned along its outer longitudinal end, each orifice being surrounded by an edge protruding from the outer surface of the longitudinal edge, and each orifice having a longitudinal edge extending from the outer surface of the longitudinal edge. The distributor body is arranged in the internal cavity of the burner body so that each orifice of the distributor body is coaxial with the orifice of the burner body. The sizes of the distributor body and the burner body are designed so that the inner diameter D2 of the orifice of the burner body is larger than the outer diameter D1 of the highest point of the edge of the orifice of the distributor body arranged facing the same orifice, so that there is a gap for air to pass between the highest point of the outer longitudinal edge of each branch and the inner surface of the burner body, and the highest point of the edge of each orifice is adjacent to the inlet of the orifice it faces, so that when the burner body is connected to an air supply source and the distributor body is connected to a gas supply source, air enters the burner body, circulates between the branches of the distributor body and in the gaps, and escapes from the burner through the edge of the burner body, while gas enters the accommodating portion of the distributor body, circulates in the laminar space of the branches, then passes through the orifices and edges of the distributor body, and finally passes through the edge of the burner body, where the gas meets and mixes with the air.

[0016] Thanks to these characteristics of the invention, the gas and air circulate in the burner through separate circuits, with minimal load losses, and are mixed only at the last moment inside the edges of the burner body. These edges thus constitute micro-chambers for mixing gas and air, and combustion takes place at the surface, i.e. leaving these edges, thus preventing any flashback.

[0017] This burner is therefore particularly suitable for use with hydrogen, a gas with a high flame propagation velocity, since flashbacks are prevented and therefore any risk of explosion or deflagration.

[0018] Furthermore, the amount of gas and air mixed is controlled, enabling a wide adjustment range to be achieved.

[0019] Other advantageous and non-limiting features according to the invention, which may be used alone or in combination, are:

[0020] At least one edge of the orifice of the burner body and / or at least one edge of the orifice of the distributor body is toothed to have a notch.

[0021] -The burner body is formed by a cylindrical shell, the rear end of which is closed by a rear wall, and the front end of which is equipped with a front wall flange that can be connected to an air supply source, the orifices of the burner body are formed in the shell so that rows of orifices extend axially on the shell, the distributor body includes a hollow cylinder, which defines the housing portion of the body, which is located in the center and is cylindrical, and the longitudinal gas distribution branches extend radially around the cylinder, the distributor body is closed at its rear end by the rear wall and at its front end by the front flange, and the front flange is equipped with a center hole that can be connected to a gas supply source, the gas distributor includes a gas pre-distribution device, the gas pre-distribution device includes a cylindrical body, which is equipped with an axial cylindrical center opening and several stages of radial channels, each radial channel extending from the center opening to the outer surface of the cylindrical body, the gas pre-distribution device is coaxially arranged in the cylindrical housing portion of the distributor body, so that its center opening faces the center hole of the flange, and each of its radial channels leads to the laminar space of the branches of the distributor body.

[0022] -The cylindrical body of the gas pre-distribution device comprises several rear gaskets and a front gasket, each of which has a cylindrical central opening and two opposite flat surfaces, the diameters of these central openings are the same, the front gasket and the rear gasket are assembled against each other so that their respective central openings are coaxial, and the rear gasket has a series of radial grooves on one of their flat surfaces, and the radial grooves define the radial channel with the opposite surface of the adjacent rear gasket.

[0023] - the gas pre-distribution device comprises means for moving the gas entering the gas pre-distribution device so as to cause a spiral motion of the gas as it circulates within the central opening of the cylindrical body.

[0024] -The means for moving the gas is a fixed propeller.

[0025] - the housing of the burner body has a rear end, wherein the rear wall of the burner body comprises a solid disk-shaped piece provided with a peripheral annular rim welded in a gas-tight manner to the rear end of the housing, the solid disk-shaped piece having a front surface and provided with at least one locating pin protruding from the front surface, the at least one locating pin being inserted between two adjacent branches of the body of the gas distributor.

[0026] - The distributor body is formed from a metal sheet which is folded on itself to form the gas distribution branches.

[0027] - The front and rear ends of each branch of the distributor body are closed by clamping and welding.

[0028] The gap for the passage of air has a height greater than or equal to 0.2 mm.

[0029] The ratio D2 / D1 of the inner diameter of the orifice of the burner body to the outer diameter of the highest point of the rim of the orifice arranged facing this same orifice is between 1.2 and 4.

[0030] - said gas is hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Other features, objects and advantages of the present invention will become apparent from the following description, which is purely illustrative and not restrictive and must be read with reference to the accompanying drawings, in which:

[0032] - Figure 1 is an exploded perspective view of the elements constituting a possible embodiment of a gas burner according to the present invention;

[0033] - Figure 2 is a perspective view of the burner with its different components in assembled position;

[0034] - Figure 3 for Figure 1 A perspective view of a gas distributor of a gas burner;

[0035] - Figure 4 To constitute Figure 3 An exploded perspective view of different components of a gas distributor;

[0036] - Figure 5 To pass along Figure 2 A longitudinal sectional view of the gas burner taken along the section of line VV;

[0037] - Figure 6 To pass along Figure 7 A longitudinal cross-sectional view of the burner body and the orifices formed in the distributor taken along the section of line VI-VI;

[0038] - Figure 7 for Figure 5 An enlarged detail of the burner body and distributor is shown. DETAILED DESCRIPTION

[0039] In the remainder of the description, the surface combustion gas burner 1 according to the invention is described as operating with a gas, preferably hydrogen. However, it can also be operated with another gas, such as natural gas, without departing from the scope of the invention.

[0040] In the remainder of the specification and claims, by convention, the term "front" refers to the position at or toward the burner into which the air is introduced (i.e. Figures 1 to 5 The term "rear" refers to an element located at or pointing to the opposite direction (i.e. Figures 1 to 5 on the right side of the screen).

[0041] Typically, a gas burner includes a burner body 2 connectable to an air supply source and a gas distributor 5 connectable to a gas supply source.

[0042] According to a preferred (thus not exclusive) embodiment of the invention, which will now be described in more detail, the burner body 2 and the gas distributor 5 are substantially cylindrical in shape.

[0043] exist Figure 1 In the figure, it can be seen that the burner body 2 is closed at its rear end 26 by a rear wall 3 and is provided at its front end 25 with a front wall flange 4, and the gas distributor 5 is closed at its rear end by a rear wall 6 and is provided at its front end with a front flange 7. These different elements will now be described.

[0044] Burner body 2:

[0045] The burner body 2 is formed by a hollow cylindrical casing 200 extending around a central longitudinal axis XX' which also constitutes the central longitudinal axis of the burner 1. This casing 200 preferably consists of a thin metal sheet.

[0046] The main body 2 defines a cylindrical inner body 20 .

[0047] The housing is perforated by a plurality of openings 21, each of which extends outwardly as an edge 22 (see in particular Figures 5 to 7 ). The edge 22 surrounds the periphery of the orifice 21. Each edge 22 protrudes from the outer surface 23 of the body 2. Each orifice 21 and its edge 22 have a central axis Z1-Z'1, which is perpendicular to the outer surface 23 (see Figure 6 ). The inner surface of the housing is marked 23'.

[0048] The rim 22, and in particular its free end 220, may advantageously be toothed, thus having notches 22'. These notches 22' serve to generate turbulence at the outlet of the body 2, thus enhancing the flame holding effect and avoiding flame extinguishing.

[0049] For example, the orifice 21 and the rim 22 are "punched holes" obtained by stamping or punching a flat metal sheet, which is then bent to form the cylindrical body 2 and the two edges of which are welded.

[0050] The orifices 21 are circular or substantially circular, and the rim 22 is cylindrical or substantially cylindrical.

[0051] Furthermore, the orifices 21 (and therefore the rims 22) are aligned to form several axial rows of orifices 24. These rows 24 extend parallel to one another and also parallel to the central longitudinal axis XX' of the body 2. Furthermore, preferably, the different rows 24 are evenly distributed over the entire circumference of the burner body 2.

[0052] In a given row 24, the different apertures 21 may be evenly spaced from one another, or may instead be grouped to form a pattern, for example, in groups of two as shown.

[0053] Back wall 3:

[0054] The rear wall 3 consists of a solid disk 30 provided with a peripheral annular rim 31. The diameter of the rear wall 3 is adapted to the diameter of the burner body 2 (here the housing 200) so that its peripheral rim 11 can be welded to the rear end 26 of the body 2, preferably inside the body 2, such as Figure 5 Thus, the rear wall 3 and the main body 2 are welded in an airtight manner by means of an annular weld.

[0055] Furthermore, the rear wall 3 is provided with at least one positioning pin 32, preferably three pins, which project from the front surface 301 of the disc 30 towards the interior of the cavity 20 when the rear wall is assembled with the body 2. Their function will be described in detail below.

[0056] Front wall flange 4:

[0057] like Figure 5 As shown, the front wall flange 4 is an annular element intended to be welded to the front end 25 of the burner body 2 to allow the body 2 to be connected to an air supply source (not shown) required for gas combustion. The flange 4, for example, comprises an annular piece 40 welded to the inside of the body 2, which extends forward as a radial flange 41 for attaching the body 2.

[0058] Gas distributor 5:

[0059] The gas distributor 5 has the function of distributing the gas, in particular hydrogen, as close as possible to the orifices 21 of the burner body 2 and also has the function of distributing the air circulating in the body 2, as will be described in more detail later.

[0060] The distributor 5 is intended to be inserted axially into the burner body 2 .

[0061] like Figure 1 and Figures 3 to 5 As shown, the dispenser 5 comprises a dispenser body 50 , a rear wall 6 and a front flange 7 .

[0062] The body 50 comprises a hollow cylinder 51 having a central longitudinal axis X1-X'1. This axis X1-X'1 is coaxial with the axis XX' of the burner 1 when the distributor 5 is mounted in the body 2. The cylinder 51 is equipped with a plurality of radial branches 52 arranged in a star shape around the cylinder 51. The cylinder 51 defines a cylindrical central housing 53. Each branch 52 extends both radially outwards with respect to the central axis X1-X1' and over the entire length of the cylinder 51.

[0063] from Figure 7 As can be seen more clearly in the figure, each branch 52 comprises two flat walls 54, 54', which are parallel or substantially parallel to each other and spaced apart to form between them a laminar space 55, which opens at its radially inner end into the cylindrical central housing 53. The two walls 54, 54' meet each other at their radially outer ends by a joining area which defines a radially outer longitudinal edge 56 of each branch 52. This edge 56 preferably has an inwardly curved shape along its cross section, with its concave surface facing the laminar space 55.

[0064] Preferably, the body 50 consists of a strip of sheet metal, bent to form a cylinder 51 and folded several times on itself to form each branch 52 leading to a housing 53 .

[0065] from Figure 3 It can be seen that each branch 52 is closed in an airtight manner at its front end 57 and rear end 57 ′, for example by clamping the two walls 54 , 54 ′ and then welding the edges of these walls to each other.

[0066] Finally, the radially outer longitudinal edge 56 of each branch 52 is perforated by a plurality of orifices 58, each of which extends through a rim 59 (see Figure 6 and Figure 7 ). The rim 59 surrounds the periphery of the orifice 58. Each rim 59 projects outwardly from the radially outer surface 560 of the edge 56. Each orifice 58 and its rim 59 have a central axis Z2-Z'2 perpendicular to the outer surface 560.

[0067] The rim 59 may advantageously be toothed so as to have notches 59 ′, making it possible to generate turbulence when leaving the rim 59 and thus improve the air / gas mixture passing through the orifice 21 and then through the rim 22 .

[0068] The openings 58 and the rim 59 are, for example, "punchings" obtained by stamping a metal sheet. These openings 58 are circular or substantially circular, and the rim 59 is cylindrical or substantially cylindrical.

[0069] The distributor body 50 comprises at most as many branches 52 as there are rows 24 of orifices 21 in the burner body 2. The number of branches 52 may be less than the number of rows 24 of orifices, in which case air will only leave the rows 24 of orifices. Preferably, the number of branches 52 is as many as there are rows 24 of orifices.

[0070] The apertures 58 (and therefore the edges 59) are aligned axially along the longitudinal edges 56. Furthermore, on each longitudinal edge 56 of each branch 52, the number of apertures 58 is as great as the number of apertures 21 in a row 24 of the burner body 2. On a given longitudinal edge 56, the different apertures 58 may be evenly spaced from one another, or may instead be divided into a plurality of groups of apertures to form a pattern, for example grouped in groups of two, as shown.

[0071] The rear wall 6 is a disk-shaped piece whose outer diameter is equal to the inner diameter of the cylindrical central housing 53 , and it is welded to the cylinder 51 in a gas-tight manner to close said housing 53 .

[0072] The front flange 7 makes it possible to connect the distributor body 50 to a supply of pressurized gas (hydrogen) (not shown in the figures).

[0073] The front flange 7 preferably comprises a disc 70 perforated by a central hole 71. The outer diameter of the disc 70 is equal to the inner diameter of the cylindrical central housing 53, and the disc 70 is welded to the front end of the cylinder 51 at its periphery in an airtight manner, as shown in FIG. Figure 3 This disk 70 extends forwardly into a tube 72 with a longitudinal axis XX', which allows the front flange 7 to be connected to a gas supply source (not shown in the figures).

[0074] Assembly

[0075] The distributor 5 is inserted axially inside the cylindrical cavity 20 of the burner body 2 to which the rear wall 3 has been previously welded and to which the front wall flange 4 is then itself welded.

[0076] In this assembled position, it can be seen that the positioning pins 32 are each positioned between two adjacent branches 52 and thus prevent any rotation of the distributor 5 relative to the burner body 2 about the longitudinal axis XX′.

[0077] The assembly of the distributor 5 and the body 2 is also done so that each orifice 58 (and therefore its edge 59) is coaxial with the orifice 21 of the burner body 2 and its edge 22 (see Figure 6Alignment of the central axes Z1-Z'1 and Z2-Z'2).

[0078] size:

[0079] like Figure 6 As shown, the outer diameter D1 of the highest point 590 of each edge 59 of the distributor 50 is smaller than the inner diameter D2 of the orifice 21 of the burner body 2 that it faces.

[0080] Furthermore, the height H1 between the highest point 590 of each rim 59 (i.e. its radially outermost end) and the inner surface 23' of the housing 2 is as small as possible, so that the highest point 590 is immediately adjacent to the inlet 210 of the orifice 21. Thus, the rim 59 constitutes a gas micro-injector almost leading to the orifice 21, and the air / gas mixing is completed in the rim 22. When these two elements are cylindrical, the height H1 corresponds to the axial insertion clearance of the body 50 of the distributor 5 in the body 2. Preferably, H1 is less than or equal to 0.1 mm.

[0081] The dimensions of the distributor body 50 and the burner body 2 are designed so that there is a gap 27 for the passage of air between the highest point 561 of the longitudinal edge 56 of each branch 52 and the inner surface 23 ′ of the housing 2 .

[0082] Preferably, a height H2 between a highest point 561 of the edge 56 of each branch 52 and the inner surface 23 ′ of the housing is greater than or equal to 0.2 mm.

[0083] Preferably, a height H3 between the highest point of the free end 220 of the rim 22 of the burner body 2 and the inner surface 23 ′ of the body 2 is between 0.8 and 2 mm.

[0084] According to other embodiments not shown in the figures, the burner body 2 and the gas distributor 5 may have shapes other than cylindrical.

[0085] The burner body 2 may for example comprise only a portion of its surface serving as a combustion surface and perforated therein by an aperture 21 as previously described which is provided with a rim 22. Such a combustion surface may for example be flat, or slightly curved, or V-shaped.

[0086] In this case, the shape of the dispenser body 50 is adapted accordingly so that it can be inserted into the cavity 20 of the body 2. As mentioned above, the body 50 still comprises branches 52 pierced by orifices 58 provided with rims 59, but these branches are not radial.

[0087] Finally, the features previously described with respect to the subject matter regarding the relative positioning and dimensions of the apertures 21 and 58 will be the same.

[0088] In the particular case where both the burner body 2 and the gas distributor 5 are cylindrical, the gas burner 1 further comprises a gas pre-distribution device 8 and preferably a device 9 for moving the gas entering the device 8 .

[0089] Gas pre-distribution device 8:

[0090] In the embodiment shown, in particular Figure 1 and Figure 4 In the embodiment, the gas pre-distribution device 8 comprises a series of annular gaskets 80 assembled against each other, and a front gasket 81 (see Figure 1 and Figure 4 ).

[0091] Each annular gasket 80 has a cylindrical central opening 800 , a flat front surface 801 , an opposing flat rear surface 802 , and a cylindrical side surface 803 .

[0092] On each annular gasket 80, for example here on the front face 801, there is a series of straight grooves 804, which are dug into the thickness of the gasket and each extend radially from the central opening 800 until they open into the face 803. On each gasket 80, the number of grooves 804 is as great as the number of branches 52 in the distributor 5.

[0093] When different washers 80 are pressed against each other, the rear surface 802 of one of the washers contacts the front surface 801 of the adjacent washers, and the rear surface 802 forms a channel 805 with different grooves 804 (see FIG. Figure 1 , Figure 5 and Figure 7 ). These channels 805 have openings 806 leading to the side surface 803. Thus, a continuous number 807 of radial channels 805 are obtained.

[0094] The front gasket 81 includes a cylindrical central opening 810 , a flat front surface 811 , and an opposing flat rear surface 812 .

[0095] Openings 800 and 810 are coaxial and have the same diameter.

[0096] from Figure 4 It can be seen more clearly from the cross section that an annular shoulder 814 is formed inside the central opening 810, so that the opening 810 has a rear portion 815 (whose inner diameter is the same as the inner diameter of the opening 800) and a front portion 816 (whose inner diameter is larger than the inner diameter of the rear portion 815), so as to form a receiving portion 817 for receiving the device 9 (preferably a propeller) at the front portion 816.

[0097] The annular shoulder 814 thus enables the propeller 9 to be locked axially towards the rear.

[0098] When the front washer 81 is pressed flat against the adjacent washer 80, its rear surface 812 contacts the front surface 801 of the washer and also defines a radial channel 805 with the groove 804. The groove 804 can also be provided on the rear surface 802.

[0099] The different gaskets 80 and the front gasket 81 are assembled against each other, and the gas pre-distribution device 8 thus formed is axially inserted and housed inside the housing 53 of the distributor 5, so that the rear surface 802 of the last gasket 80 is in contact with the rear wall 6, and the front surface 811 of the front gasket 81 is in contact with the disk 70. To this end, the outer diameter of the different gaskets 80 and 81 is equal to the inner diameter of the cylinder 51 (within the limits of the insertion gap).

[0100] exist Figure 5 In the assembled position more clearly shown in FIG. 8 , it can be seen that the disk 70 interacts with the housing 817 to lock the fixed propeller 9 axially towards the front. It is therefore held between the front flange 7 and the washer 81.

[0101] The different washers 80 and 81 are positioned at an angle relative to the longitudinal axis XX' so that their respective grooves 804 overlap and the outer openings 806 of the channels 805 form an axially aligned arrangement 82, such as Figure 1 As shown. To this end, error-proofing measures can be provided on the different washers 80 and 81 to assemble them correctly. Alignment arrangement 82 is Figure 1 It is schematically indicated by a dotted line.

[0102] Furthermore, washers 80 and 81 are inserted into housing 53 so that each outer opening 806 of radial channel 805 opens directly into laminar space 55. In other words, each alignment 82 is positioned facing branch 52.

[0103] According to a simplified variant embodiment not shown in the figures, the gas predistribution device 8 can also be formed by a single solid cylindrical body instead, replacing the different gaskets 80, 81. This solid cylindrical body has an axial cylindrical central opening corresponding to a set of central openings 800 and 810 and a plurality of radial channels 805, which firstly lead to this central opening and secondly to the outer surface 803 of the cylindrical body flush with the opening 806. These different channels 805 are distributed in different stages 807 and can supply gas to the branches 52 of the distributor body. Finally, this single cylindrical body also has a housing 817 for receiving the propeller 9 at the front end of its central opening.

[0104] Note that the number of levels 807 of channels need not be as great as the number of orifices 58 (or edges 59) on the branches 52. Thus, as a purely illustrative example, in the exemplary embodiment shown in the drawings, for fourteen edges 59 on each branch 52, there are seven levels 807 of radial channels.

[0105] like Figure 4 As shown, the fixed propeller 9 comprises a central disk 91 from which a plurality of blades 92 extend. The blades 92 are oriented at a set angle, which makes it possible to turn the incoming gas so as to cause it to produce a spiral motion inside the central openings 800 and 810.

[0106] Material:

[0107] The burner body 2, the rear walls 3 and 6, the flanges 4 and 7, the gas distributor 5, the gas pre-distribution device 8 and the propeller 9 are advantageously made of metal, in particular of stainless steel, although the device 8 can be made of aluminum or of a composite material. The burner body 2 can also be made of a refractory material.

[0108] operate:

[0109] The pipe 72 is connected to a pressurized gas supply, preferably hydrogen. Furthermore, the front flange 4 is connected to a pressurized air supply.

[0110] There will now be described the trajectory of the air inside the gas burner 1. This trajectory is indicated by the arrows marked with an index number "a".

[0111] Air passes through the annular space around the tube 72 ( Figure 5 The air then flows along the wall 54 or 54' ( Figure 7 The arrow a3 in the figure) and the axial direction between the highest point 561 of the edge 56 and the inner surface 23' of the shell ( Figure 6 Finally, the air escapes through the edge 22 ( Figure 6 Arrow a5 in the figure).

[0112] There will now be described the trajectory of the gas inside the gas burner 1. This trajectory is indicated by the arrows marked with the reference number "g".

[0113] Gas inlet pipe 72 ( Figure 5 The fixed propeller 9 then drives the screw to move ( Figure 5 In the special case where the gas is hydrogen (and therefore a very volatile gas), this allows for an ideal distribution of the hydrogen as it enters all channels 805.

[0114] Therefore, the gas is inserted into different channels 805 ( Figure 5 and Figure 7 arrow g3 in the figure), and then leave from them into the layered space 55 ( Figure 5 and Figure 7 The gas has previously been distributed in different channels 805, and each laminar space 55 can be evenly supplied with gas over its entire axial length.

[0115] The gas then leaves through the orifice 58 and edge 59 of the distributor 5 ( Figure 6 The arrow g5 in the figure then passes through the opening 21 and the edge 22 ( Figure 6 Arrow g6 in ), and thus mix with air there. Therefore, only in these edges 22, the air / gas mixes and burns when leaving the edges 22, so there is no risk of flashback in the space 520 or radial branch 52.

[0116] The gas burner according to the invention thus makes it possible to operate with hydrogen, although this gas is very volatile, while offering a power adjustment range of at least 1 to 10, without the risk of flashback and therefore also without the risk of deflagration or explosion.

[0117] Finally, the measurements carried out have made it possible to demonstrate that combustion with hydrogen takes place at an air lambda λ of 1.3 to 2 and a nitrogen oxide Nox emission level of 0.5 to 3 ppm.

[0118] In the embodiment in which no pre-distribution device 8 is present, the gas leaving the tube 72 passes directly through the receptacle 53 .

Claims

1. A deflagration and explosion-proof surface combustion gas burner (1), characterized in that: It comprises a burner body (2) made of metal or refractory material and a gas distributor (5). The burner body (2) defines an internal cavity (20) connectable to an air supply source and has an outer surface (23) and an inner surface (23'). The burner body (2) is perforated by a series of orifices (21), each orifice extending through a rim (22) protruding from the outer surface (23) and with a central axis (Z1-Z'1) of the rim (22) perpendicular to the outer surface (23), the orifices (21) being arranged in several rows (24) of aligned orifices (21), The gas distributor (5) comprises a distributor body (50) defining a housing (53) connectable to a gas supply source, The distributor body (50) comprises a plurality of longitudinal gas distribution branches (52), each branch (52) comprising two longitudinal walls (54, 54') spaced apart from each other to define a longitudinal layered gas distribution space (55) between each other, the longitudinal layered gas distribution space (55) leading to the receiving portion (53) at its inner longitudinal end (550), the two walls (54, 54') of each branch (52) being connected to form an outer longitudinal edge (56), a closed front end (57) and a closed rear end (57') of the branch (52), Each branch (52) is perforated by a series of orifices (58) aligned along its outer longitudinal edge (56), each orifice (58) being surrounded by a rim (59) projecting beyond the outer surface (560) of said longitudinal edge (56) and each orifice (58) having a central axis (Z2-Z'2) perpendicular to this outer surface (560) of said longitudinal edge (56), The distributor body (50) is arranged in the internal cavity (20) of the burner body (2) so that each orifice (58) of the distributor body (50) is coaxial with the orifice (21) of the burner body (2), The dimensions of the distributor body (50) and the burner body (2) are designed so that the inner diameter D2 of the orifice (21) of the burner body (2) is larger than the outer diameter D1 of the highest point (590) of the edge (59) of the orifice (58) of the distributor body (50) arranged facing the same orifice (21), so that there is a gap (27) for air to pass between the highest point (561) of the outer longitudinal edge (56) of each branch (52) and the inner surface (23') of the burner body (2), and so that the highest point (590) of the edge (59) of each orifice (58) is adjacent to the inlet (210) of the orifice (21) it faces. Thus, when the burner body (2) is connected to an air supply source and the distributor body (50) is connected to a gas supply source, air enters the burner body (2), circulates between the branches (52) of the distributor body (50) and in the gap (27), and escapes from the burner (1) through the edge (22) of the burner body (2), while gas enters the receiving portion (53) of the distributor body (50), circulates in the laminar space (55) of the branch (52), then passes through the orifice (58) and edge (59) of the distributor body (50), and finally passes through the edge (22) of the burner body (2), where the gas and air meet and mix.

2. The gas burner (1) according to claim 1, characterized in that At least one edge (22) of the orifice (21) of the burner body (2) and / or at least one edge (59) of the orifice (58) of the distributor body (50) is toothed to have notches (22', 59').

3. The gas burner (1) according to claim 1 or 2, characterized in that: The burner body (2) is formed by a cylindrical housing (200), the rear end (26) of which is closed by a rear wall (3), and the front end (25) of which is equipped with a front wall flange (4) capable of being connected to an air supply source. The apertures (21) of the burner body (2) are formed in the housing (200) such that rows (24) of apertures (21) extend axially on the housing, The dispenser body (50) comprises a hollow cylinder (51) defining the housing portion (53) of the body, the housing portion (53) being centrally located and cylindrical, A longitudinal gas distribution branch (52) extends radially around the cylinder (51), The distributor body (50) is closed at its rear end by a rear wall (6) and at its front end by a front flange (7), the front flange (7) being provided with a central hole (71) capable of being connected to a gas supply source, The gas distributor (5) comprises a gas pre-distribution device (8), the gas pre-distribution device (8) comprising a cylindrical body, the cylindrical body being provided with an axial cylindrical central opening (800, 810) and a plurality of stages (807) of radial channels (805), each radial channel (805) extending from the central opening (800, 810) to the outer surface (803) of the cylindrical body, The gas pre-distribution device (8) is coaxially arranged in the cylindrical receiving portion (53) of the distributor body (50) so that the central opening (800, 810) faces the central hole (71) of the flange (7), and each radial channel (805) leads to the laminar space (55) of the branch (52) of the distributor body (50).

4. The gas burner (1) according to claim 3, characterized in that The cylindrical body of the gas pre-distribution device (8) comprises a plurality of rear gaskets (80) and a front gasket (81), wherein the rear gaskets (80) and the front gasket (81) respectively have a cylindrical central opening (800, 810) and two opposite flat surfaces (801, 802, 811, 812), wherein the diameters of the central openings (800, 810) are the same, the front gasket (81) and the rear gasket (80) are assembled against each other so that their respective central openings (800, 810) are coaxial, and the rear gasket (80) has a series of radial grooves (804) on one of its flat surfaces (801, 802), wherein the radial grooves (804) define the radial channel (805) with the opposite surfaces (802, 801) of the adjacent rear gasket (80).

5. The gas burner (1) according to claim 3 or 4, characterized in that The gas pre-distribution device (8) comprises means (9) for moving the gas entering the gas pre-distribution device (8) so that the gas generates a spiral motion when circulating in the central opening (800, 810) of the cylindrical body.

6. The gas burner (1) according to claim 5, characterized in that The means (9) for moving the gas is a fixed propeller.

7. The gas burner (1) according to any one of claims 3 to 6, characterized in that The shell (200) of the burner body (2) has a rear end (26), and the rear wall (3) of the burner body (2) includes a solid disk-shaped member (30), which is provided with a peripheral annular rim (31) welded to the rear end (26) of the shell (200) in a gas-tight manner, and the solid disk-shaped member (30) has a front surface (301) and is provided with at least one positioning pin (32) protruding from the front surface (301), and the at least one positioning pin (32) is inserted between two adjacent branches (52) of the body (50) of the gas distributor (5).

8. A gas burner (1) according to any one of the preceding claims, characterised in that The distributor body (50) is formed from a metal sheet which is folded upon itself to form the gas distribution branches (52).

9. The gas burner (1) according to claim 8, characterized in that The front end (57) and the rear end (57') of each branch (52) of the distributor body (50) are closed by clamping and welding.

10. Gas burner (1) according to any one of the preceding claims, characterized in that The gap (27) for the passage of air has a height (H2) greater than or equal to 0.2 mm.

11. Gas burner (1) according to any one of the preceding claims, characterized in that The ratio D2 / D1 of the inner diameter (D2) of the orifice (21) of the burner body (2) to the outer diameter (D1) of the highest point (590) of the edge (59) of the orifice (58) arranged facing the same orifice (21) is between 1.2 and 4.

12. Gas burner (1) according to any one of the preceding claims, characterized in that The gas is hydrogen.

Images