Burner for a cooking or gas hob

Abstract

The invention provides a premixer burner for a gas stove comprising a gas injector (12), a tubular mixer with venturi effect (20, 22), a burner support (26) one of which is closed by a cap (28), characterized in that the tubular mixer comprises an outer tube (20), and an inner tube (22) with venturi effect coaxial with the outer tube (20) which, in its thickness, comprises at least one axial slot (60) whose width increases progressively from the rear to the front in the inner tube (22) to progressively increase the effective passage section inside the tubular mixer (20, 22), whereby, by venturi effect, air is sucked in by the gas which is injected to produce the combustible air-gas mixture in the burner (10).

Description

Domaine technique de l'invention

[0001] The invention relates to a burner for a gas stove or cooker.

[0002] The invention relates more particularly to a burner allowing the implementation of ecological and “low carbon” manufacturing techniques. Arrière-plan technique

[0003] The invention relates in particular to a burner known as a "premixer burner" of the type comprising a gas injector which is connected to a tubular mixer with a venturi effect which is itself connected to a support, in the general form of a pot or a cylindrical cup, an open upper face of which is closed by a cap attached to close this upper face.

[0004] As is known, all or part of these components are manufactured in a foundry by metal casting, particularly in cast iron or brass.

[0005] This type of manufacturing has many disadvantages.

[0006] First of all, it is totally unsuitable for the production of burner models in small series, because it requires the use of molds corresponding to each range of burners.

[0007] In addition, production costs are very high and transport costs linked to the weight of parts and components are very high, as are the various negative impacts on the environment, whether it concerns transport but also casting and foundry techniques with the impacts linked in particular to the various polluting emissions and the significant energy consumption linked to their implementation.

[0008] Furthermore, the creation of the conical or truncated internal profile to obtain the desired venturi effect requires the implementation of complex machining techniques.

[0009] Document FR2025027A1 proposed implementing alternative technologies for the production of the burner body with its tubular venturi effect mixer, but the proposed solution of cutting a cut, folded and crimped sheet metal is very complex and not very suitable for the simple production of ranges of burners of different dimensions and heating capacities.

[0010] The invention aims to remedy all or part of these drawbacks. Résumé de l'invention

[0011] The invention provides a burner for a gas stove or cooker comprising a gas injector which is connected to a rear end of a tubular venturi effect mixer whose front end is connected to a support, characterized in that the tubular mixer comprises: an outer casing tube whose internal section is cylindrical; and an inner tube with a venturi effect coaxial with the outer tube; -- which is adjacent to the concave inner wall of the outer tube; - whose concave inner wall is cylindrical; -- and which, in its thickness, comprises at least one axial slot whose width increases progressively according to the direction of flow of the gas from back to front inside the inner tube in order, according to the direction of flow of the gas injected axially into the inner tube, to progressively increase the effective passage section inside the tubular mixer, whereby, by venturi effect, air is drawn in by the gas which is injected to produce the combustible air-gas mixture in the burner.

[0012] Thanks to such a design of the tubular mixer, it is possible to produce it very simply from two sections of complementary coaxial outer and inner metal tubes, commercially available, and by carrying out, in a single step - preferably but not limited to the laser cutting technique - a material removal operation for the production of each axial slot.

[0013] According to other burner characteristics: each axial slot opens axially at the front free end of the inner tube; each axial slot is delimited laterally by two opposite edges giving it a flared profile; each axial slot is delimited laterally by two opposite rectilinear edges giving it a “V” profile; the inner tube comprises several axial slots which are distributed angularly around the axis of the inner tube; said several axial slots are distributed angularly in a regular manner around the axis of the inner tube; each axial slot is produced by laser cutting of the inner tube; the burner comprises a single-piece bracket which carries the gas injector, which is connected to the rear end of the tubular mixer, and which is produced by laser cutting;an open upper face of said support is closed by a cap (28), and the support comprises at least one tubular section which comprises a crown of outlet ports for the air-gas combustible mixture which are formed near an upper end edge of said tubular section and / or a crown of axial outlet slots for the air-gas combustible mixture which open axially into said upper end edge of said tubular section; said axial outlet slots for the air-gas combustible mixture which open axially into said edge are closed axially by said cap; each port and / or each axial outlet slot is produced by laser cutting; the support comprises a plenum comprising a distribution box for the air-gas combustible mixture to which the front end of the tubular mixer with venturi effect is connected;and a plurality of parallel horizontal and blind tubular bodies, each of which comprises: -- a free inlet end connected to the distribution box which is supplied with air-gas combustible mixture; -- and at least one series of outlet orifices for the air-gas combustible mixture which are distributed along the tubular body; each tubular body is surmounted by a horizontal protective plate which is offset upwards and which extends above the outlet orifices for the air-gas combustible mixture; each tubular body is surmounted by a stiffening plate, for example a horizontal plate which is mounted on the tubular body by a bayonet hook system. ; Brève description des figures

[0014] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: [ Fig.1 ] - there figure 1 is a perspective view of an exemplary embodiment of a burner according to the invention; [ Fig.2 ] - there figure 2 is a view - from another angle - in exploded perspective of the burner shown in the figure 1 ; [ Fig.3 ] - there figure 3 is a view from another perspective angle of the burner of the figure 2 ; [ Fig.4 ] - there figure 4 is a perspective and sectional view through a longitudinal and horizontal plane passing through the longitudinal axis of the outer and inner tubes of the burner of the figure 1 ; [ Fig.5 ] - there figure 5 is a sectional view through a longitudinal and vertical plane passing through the longitudinal axis of the outer and inner tubes of the burner of the figure 1 ; [ Fig.6 ] - there figure 6 is an exploded and enlarged perspective detail view of the outer and inner tubes of the burner of the figure 1 ; [ Fig.7A ] - there figure 7A is a partial perspective view of the outer and inner tubes of the burner of the figure 2 which are represented in section by the transverse and vertical plane 7A-7A of the figure 5 ; [ Fig.7B ] - there figure 7B is a view analogous to that of the figure 7A-7A on which the outer and inner tubes of the burner of the figure 2 are represented in section by a transverse and vertical plane which is axially offset forwards relative to the section plane of the figure 7A ; [ Fig.7C ] - there figure 7C is a view analogous to that of the figure 7B on which the outer and inner tubes of the burner of the figure 2 are represented in section by a transverse and vertical plane which is axially offset forwards relative to the section plane of the figure 7B ; [ Fig.7D ] - there figure 7D is a view analogous to that of the figure 7C on which the outer and inner tubes of the burner of the figure 2 are represented in section by a transverse and vertical plane which is axially offset forwards relative to the section plane of the figure 7C ; [ Fig.7E ] - there figure 7E is a view analogous to that of the figure 7D on which the outer and inner tubes of the burner of the figure 2 are represented in section by a transverse and vertical plane which is axially offset forwards relative to the section plane of the figure 7D ; [ Fig.7F ] - there figure 7F is a view analogous to that of the figure 7E on which the outer and inner tubes of the burner of the figure 2 are represented in section by a transverse and vertical plane which is axially offset forwards relative to the section plane of the figure 7E ; [ Fig.8 ] - there figure 8 is a partial perspective view in section through a vertical longitudinal plane of an alternative embodiment of the support and the burner cap of the figure 1 ; [ Fig.9 ] - there figure 9 is a view is a perspective view of another exemplary embodiment of a burner according to the invention; [ Fig.10 ] - there figure 10 is a perspective view from another angle and partially exploded of the burner of the figure 9 . Description détaillée de l'invention

[0015] For the description of the invention and the understanding of the claims, the vertical, longitudinal and transverse orientations according to the V, L, T reference system indicated in the figures, the longitudinal L and transverse T axes of which extend in a horizontal plane, will be adopted as a non-limiting example and without limiting reference to Earth's gravity.

[0016] By convention, the longitudinal axis L is oriented from rear to front parallel to the direction of gas flow.

[0017] In the following description, identical, similar or analogous elements will be designated by the same reference numbers.

[0018] We have represented at the figures 1 à 3 a burner 10 which, from rear to front along the longitudinal axis AL, successively comprises: a gas injector 12 with its supply connection 14; a bracket 16 which carries the gas injector 12; a rear ring 18 for fixing the outer tube 20 on the bracket 16; the outer tube 20 and an inner tube 22 coaxial with the outer tube 20 along their common longitudinal axis AL; a front ring 24 for fixing the outer tube 20 on a burner support 26; and the burner support 26 with its upper cap 28.

[0019] The 16 bracket is made from a single piece of sheet metal laser-cut from a section of tube.

[0020] The stirrup 16 comprises two parallel longitudinal arms 30 which connect a rear transverse collar 32 and a front transverse collar 34.

[0021] The rear transverse collar 32 has a central hole 33 allowing the injector 12 to be fixed inside the caliper 16 by screwing its threaded rear end 13 into the front end 15 of the connector 14.

[0022] The front transverse collar 34 has a central hole 35 allowing the rear ring 18 to be fixed to the stirrup 16, for example by welding.

[0023] The outer tube 20 is here a cylindrical tube of circular section whose rear end 19, here of reduced diameter, is designed to be mounted coaxially inside the rear ring 18 and to be fixed to it, for example by welding.

[0024] Similarly, the front end 21 is designed to be mounted coaxially inside the front ring 24 and fixed thereto, for example by welding.

[0025] The support 26 comprises two coaxial tubular sections along the vertical axis AV, here of cylindrical tube of circular section, including an outer tubular section 36 of larger diameter and an inner tubular section 38 of smaller diameter.

[0026] Each tubular section 36, 38 is produced by laser cutting a tube of corresponding dimensions.

[0027] The two coaxial tubular sections 36 and 38 are mounted coaxially and fixed to each other by an annular lower plate 40 which is also made of laser-cut sheet metal.

[0028] The plate 40 here comprises a diametrical crosspiece with a central hole 41 allowing the support 26 to be fixed to any corresponding support, for example by means of a bolt or a screw.

[0029] The two coaxial tubular sections 36 and 38 delimit between them an annular passage or channel 42 for the passage of the air-gas mixture through the support 26.

[0030] For this purpose, in the lower part, the outer tubular section 36 has a hole 44, made by laser cutting, allowing the front ring 24 to be fixed to the outer tubular section 36, for example by welding.

[0031] The annular space 26 is thus connected to the outer tube 20 and it is supplied with air-gas mixture through the front ring 24 and the orifice 44.

[0032] The cap 28 ensures the “closure” of the upper end face of the annular space 42 at its upper end.

[0033] For this purpose, the cap 28 is in the form of an annular plate produced by laser cutting.

[0034] For its positioning and maintenance on the upper end of the support 26, the annular cap 28 has external notches 27 and internal notches 29.

[0035] The outer notches 27 receive, if necessary with a slightly tight assembly, axial lugs 37 which extend vertically upwards from the upper axial end edge 46 of the outer tubular section 36.

[0036] The inner notches 29 receive, if necessary with a slightly tight assembly, axial lugs 39 which extend vertically upwards from the upper axial end edge 48 of the inner tubular section 38.

[0037] Here, the assembly and fixing of the cap 28 on the support 26 is thus of the type with tenons 37, 39 and mortises 27, 29.

[0038] To constitute outlet orifices for the air-gas mixture for the formation of corresponding flames, at the upper part of the support 26, the outer tubular section 36 here comprises, without limitation, a series of axial slots 50 (arranged angularly in a regular manner in a crown) which open axially into the upper edge 46 and which are closed by the cap 28.

[0039] As a supplement, but not limited to, to constitute other combustion orifices for the air-gas mixture for the formation of corresponding flames, at the upper part of the support 26, the inner tubular section 38 here comprises, without limitation, a series of axial slots 52 (arranged angularly in a regular manner in a crown) which open axially into the upper edge 48 and which are closed by the cap 28. The presence or absence of axial slots, their number and / or their distribution depend in particular on the heating power which it is desired to obtain.

[0040] As a variant not shown, each gas outlet orifice may consist of a blind light - or hole - formed in the tubular section 36, 38 near the cap 28.

[0041] Each tubular section 36, 38 with its various functional parts (Fingers 37, fingers 39, orifice 44, slots 50, slots 52) is advantageously produced by laser cutting. In accordance with the main characteristic of the invention, the tubular venturi effect mixer which is supplied with gas and air at its rear axial end to constitute an air-gas mixer which is constituted by the association of the tube 20, which constitutes an outer casing tube, and the tube 22 which constitutes an inner venturi effect tube.

[0042] The design of the inner tube 22 is such that it allows it to be produced simply and economically by laser cutting a tube or section of tube which is here cylindrical with a circular section.

[0043] The dimensions of the two tubes are such that the inner tube 22 is received axially without play inside the outer tube 20.

[0044] The inner tube 22 is delimited by its convex cylindrical outer wall 54 which is adjacent to the concave cylindrical inner wall 58 of the outer tube 20.

[0045] The concave inner wall 56 of the inner tube 22 is cylindrical.

[0046] Depending on the direction of flow of the gas injected axially into the inner tube 22 - from back to front - and so as to progressively increase the effective passage section inside the tubular mixer 20-22, the inner tube here comprises a series of three axial slots 60 with a venturi effect.

[0047] The three slots 60 are here distributed angularly in a regular manner at 120 degrees of angle.

[0048] Each axial slot 60 is here formed throughout the thickness of the wall of the inner tube 22. Each axial slot 60 opens axially at the front free end 23AV of the inner tube 22.

[0049] Each slot 60 is delimited laterally by two opposite edges 62 giving it a flared profile.

[0050] Each edge 62 is here rectilinear and gives each slot a flared profile in the shape of a “V”. As can be seen for example figure 5 and to the figures 7B à 7E , the “width” L of each axial slot 60 increases progressively according to the direction of flow of the gas from rear to front inside the inner tube 22.

[0051] Here, width L is understood to mean the average distance, measured circumferentially in a transverse plane, separating the two opposite edges 62 of a slot 60.

[0052] As can be seen in particular in figures 1 , 4 et 5 , the rear free end section of the inner tube 22 projects axially rearward beyond the rear axial end of the outer tube 20.

[0053] At its rear axial end 23AR, the inner tube 22 here comprises three V-shaped notches 64 which open into the rear axial end edge 23AR.

[0054] The role of these notches The role of these notches is to create a progressive reduction in the passage section to create an acceleration of the gas flow at the outlet of the injector to create a depression which sucks (drives) the outside air towards this passage. This is the beginning of the venturi effect.

[0055] Depending on the power of the burner, this part can be adjusted by moving it closer or further to the injector 12 to adjust the proportion of air that enters.

[0056] According to the variant embodiment of the burner support and cap shown in figure 8 , only the outer tubular section 36 of larger diameter has axial slots 46.

[0057] Many variations are possible without departing from the general framework of definition of the invention.

[0058] For example, the tubes or tube sections 20, 22, 36, 38 are not necessarily of circular section but may be of square section, always produced by laser cutting in corresponding tubes of corresponding square section.

[0059] We will now describe the other example of the embodiment of a burner shown in figures 9 And 10 which is particularly suited to so-called “barbecue” cooking.

[0060] In this example, the design of the assembly constituting the tubular venturi effect mixer according to the invention is identical to what has been described with reference to figures 1 à 8 and similar or identical elements and components are designated by the same reference numerals.

[0061] The front end 21 is designed to be mounted coaxially inside a front ring 24, and to be fixed to it for example by welding, which here belongs to a right-angled tubular elbow 70 whose downstream section 72 extends vertically.

[0062] The support 26 here comprises a plenum 74 for distributing the air-gas combustible mixture to which the front end of the tubular venturi effect mixer is connected.

[0063] For this purpose, the plenum 74 comprises a horizontal housing 76 of rectangular parallelepiped shape which extends horizontally and which comprises an inlet orifice 78 formed in its lower wall 79 and to which the downstream section 72 of the elbow 70 is connected and fixed, for example by welding.

[0064] The 76 housing is made from a steel tube of corresponding section.

[0065] In one of its two vertical side walls, the housing 76 has a series of outlet orifices 82 (here five in number) which are distributed regularly along the wall 80.

[0066] The plenum 74 has the function, through the outlet orifices 82, of distributing the air-gas combustible mixture into a plurality of horizontal and blind parallel tubular bodies 84, each of which constitutes a tubular burner and comprises a free inlet end 86 which is connected to an outlet orifice 82 of the housing 76 to which it is fixed, for example by welding.

[0067] Each tubular body 84 comprises, here along its entire length, two parallel series of outlet orifices 88 for the combustible air-gas mixture - for the formation of corresponding flames - which are here distributed regularly along the tubular body 84.

[0068] Each series of orifices 88 is offset laterally relative to a median vertical plane of the tubular body 84.

[0069] In order to protect the outlet orifices 88 and prevent them from being blocked, for example, by cooking residues, each tubular body 84 is surmounted by a horizontal protective plate 90 which is offset upwards and which extends above the outlet orifices 88 of the air-gas combustible mixture.

[0070] Each protective plate 90 is mounted and removably fixed on the associated tubular body 84 by means of a mounting bar 92.

[0071] Each bar 92 is fixed to the upper part of the tubular body 84, here by welding, and it extends in the median vertical plane.

[0072] In its upper edge 94, each bar comprises a series of hooks 96 which is capable of being received in a complementary notch 98 formed in the protective plate 90, to allow a reliable assembly of the “bayonet” type.

[0073] In addition, the protective plate 90 thus hooked onto the mounting bar 92 contributes to the stiffening of the associated tubular burner body 84.

Claims

1. Burner (10) for a gas stove or cooker comprising a gas injector (12) which is connected to a rear end of a tubular venturi mixer (20, 22) whose front end is connected to a support (26), characterized in thatthe tubular mixer comprises: - an outer casing tube (20) whose internal section is cylindrical; - and an inner tube (22) with a venturi effect coaxial with the outer tube (20); -- which is adjacent to the concave internal wall (58) of the outer tube (20); -- whose concave internal wall (56) is cylindrical; -- and which, in its thickness, comprises at least one axial slot (60) whose width (L) increases progressively according to the direction of flow of the gas from back to front inside the inner tube (22) in order, according to the direction of flow of the gas injected axially into the inner tube (22), to progressively increase the effective passage section inside the tubular mixer (20, 22), whereby, by venturi effect, air is sucked in by the gas which is injected to produce the combustible air-gas mixture in the burner (10).

2. Burner (10) according to claim 1, characterized in thateach axial slot (60) opens axially at the front free end (23A) of the inner tube (22).

3. Burner (10) according to any one of the preceding claims, characterized in that each axial slot (60) is delimited laterally by two opposite edges (62) giving it a flared profile.

4. Burner (10) according to the preceding claim, characterized in that each axial slot (60) is delimited laterally by two opposite rectilinear edges (62) giving it a “V” profile.

5. Burner (10) according to any one of the preceding claims, characterized in that the inner tube (22) comprises several axial slots (60) which are distributed angularly around the axis (AL) of the inner tube (22).

6. Burner (10) according to the preceding claim, characterized in that said several axial slots (60) are distributed angularly in a regular manner around the axis (AL) of the inner tube (22).

7. Burner (10) according to any one of the preceding claims, characterized in that each axial slot (60) is made by laser cutting the inner tube (22).

8. Burner (10) any one of the preceding claims, characterized in that it comprises a single-piece bracket (16) which carries the gas injector (12), which is connected to the rear end of the tubular mixer (20, 22) with venturi effect, and which is produced by laser cutting.

9. Burner (10) any one of the preceding claims, characterized in that an open upper face of said support (26) is closed by a cap (28), and in thatthe support (26) comprises at least one tubular section (36, 38) which comprises a crown of outlet ports for the air-gas combustible mixture which are formed near an upper end edge (46, 48) of said tubular section and / or a crown of axial slots (50, 52) for the air-gas combustible mixture which open axially into said upper end edge (46, 48) of said tubular section (36, 38).

10. Burner (10) according to the preceding claim, characterized in that said axial slots (50, 52) for the outlet of the air-gas combustible mixture which open axially into said edge are closed axially by said cap (28).

11. Burner (10) according to one of claims 9 or 10, characterized in that each light and / or each outlet slot is produced by laser cutting.

12. Burner according to any one of claims 1 to 8, characterized in thatsaid support comprises: - a plenum (74) comprising a housing (76) for distributing the air-gas combustible mixture to which the front end (21) of the tubular venturi effect mixer (20, 22) is connected; - and a plurality of horizontal and blind parallel tubular bodies (84), each of which comprises: -- a free inlet end (86) connected to the distribution housing (76) which is supplied with air-gas combustible mixture; -- and at least one series of outlet orifices (88) for the air-gas combustible mixture which are distributed along the tubular body (84).

13. Burner according to the preceding claim, characterized in that each tubular body (84) is surmounted by a horizontal protective plate (90) which is offset upwards and which extends above the outlet orifices (88) of the air-gas combustible mixture.

14. Burner according to claim 12, characterized in that each tubular body (84) is surmounted by a horizontal stiffening plate (90).

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