BURNER FOR INDUSTRIAL OVENS

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to the general technical field of heat generation installations for industrial processes, and more specifically to the fuel and oxidizer supply devices of such installations. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] Heat generation systems, including burners, typically comprise a fuel supply circuit and an oxidizer supply circuit configured to feed, respectively, a fuel injection circuit and an oxidizer injection circuit of the burner. The fuel and oxidizer are injected by the burner in proportions controlled according to various physical parameters, including the type of fuel, the power output, and the temperature to be reached by the burner.

[0003] Due to the known proportional relationship between fuel and oxidizer flow rates during normal burner operation, a common control system for the fuel and oxidizer supply circuits has been conventionally proposed. A single actuator provides a distributed force to an effector located in the fuel supply circuit and an effector located in the oxidizer supply circuit, with the effector configured to vary the fuel or oxidizer flow rate in the respective supply circuit.

[0004] Such a solution therefore makes it possible to respect in all circumstances the proportion of fuel and oxidizer flow rates, defined during the design of the burner, when these flow rates are modified.

[0005] Classically, the effectors located respectively in the fuel supply circuit and in the oxidizer supply circuit are of the butterfly type, comprising a body defining a portion of the pipe, a sealing element extending into the pipe, a lever mounted for rotation in the body and connected to the sealing element, such that an action on the lever causes a movement of the sealing element modifying the area of ​​the passage section of the portion of the pipe.

[0006] These solutions, however, present the problem of a non-linearity between the control signal and the resulting flow rate change. This can be compensated for by using a cam profile, but this complicates the device and increases its size, making its integration into compact burners difficult. Prior art burners are known from publications US 3,371,699, US 4,793,798 A, and US 2017 / 219247 A1. These burners combine air and fuel gas regulation mechanisms, but the type of valves differs from the claimed valves.

[0007] Therefore, there is a need to simplify this type of device in order to allow integration into a greater number of types of installations. Summary of the invention

[0008] To overcome the limitations of the prior art, the invention proposes a burner for an industrial furnace comprising a fuel supply assembly and an oxidizer supply assembly, the fuel supply assembly comprising, from upstream to downstream, a fuel inlet manifold configured to receive fuel, a fuel distribution device configured to control a fuel flow rate, and a fuel injection device configured to inject fuel into the furnace; the oxidizer supply assembly comprising an oxidizer inlet manifold configured to receive oxidizer, an oxidizer distribution device configured to control an oxidizer flow rate, and an oxidizer injection device configured to inject oxidizer into the furnace, wherein: The oxidizer distribution device comprises a movable shutter through which a first opening is provided, a stator through which a second opening is provided, a drive shaft integral with the movable shutter capable of rotating the movable shutter, the movable shutter being located opposite the stator in such a way that, when driven by the drive shaft, the first opening is positioned at least partially opposite the second opening so as to create an oxidizer passage connecting the oxidizer intake manifold and the oxidizer injection device, the first and second openings being shaped so that the oxidizer passage has a cross-section with a surface area that varies according to the angular position of the drive shaft,The fuel distribution device comprises a fixed element including an inlet connected to the fuel intake manifold, an outlet connected to the fuel injection device, a second movable shutter rotatably mounted in the fixed element, the second movable shutter comprising a wall defining a cavity opening at the outlet into the fuel injection device, the wall closing the inlet of the fixed element, a light being provided through the wall so as to form a lateral opening, the second movable shutter being integral with the drive shaft such that, when the drive shaft is rotated, the light is positioned partially opposite the inlet of the fixed element so as to create a fuel passage connecting the fuel intake manifold and the cavity connected to the fuel injection device,The opening and inlet are shaped so that the fuel passage has a cross-sectional area that varies depending on the angular position of the drive shaft.

[0009] Such a burner therefore allows the flow of fuel and oxidizer to be varied proportionally by means of a single moving element, which greatly limits the size and complexity of such a device.

[0010] Advantageously, such a burner can be complemented by the following features, taken alone or in combination: the first aperture has the shape of an angular portion of an annular element, and the second aperture has the shape of an angular portion of an annular element; the light has a shape such that the projection of the light onto a plane forms an angular portion of a disk; the angular position of the light and the angular positions of the first and second apertures are configured so that the rotation of the drive shaft causes a simultaneous and proportional change in the respective areas of the fuel passage and the oxidizer passage; the drive shaft extends along a principal axis of the burner, the movable shutter and the second movable shutter being coaxial and extending along the principal axis; the stator includes a disk having an aperture in which is mounted a mixer comprising a perforated grid configured to generate turbulence in the flow of the oxidizer stream;The drive shaft comprises an external sleeve adjustablely mounted on an internal shaft and extending outwards from the internal shaft; the internal shaft extending through an opening formed through the movable shutter and the stator and being fixed to the second movable shutter; the external sleeve being connected to the movable shutter in a sealed manner; the drive shaft extends along a main axis of the burner, the movable shutter and the movable shutter being coaxial and extending along the main axis; the stator is a disc comprising an opening in which a mixer is mounted; BRIEF DESCRIPTION OF THE FIGURES

[0011] The figures are presented for illustrative purposes only and are in no way limiting to the invention. [ Fig.1 [ ] is a schematic cross-sectional profile view of a burner according to the invention. Fig. 2a] is an axial cross-sectional view highlighting an oxidizer distribution device according to the invention, in a partially open position. Fig. 2b ] is an axial cross-sectional view highlighting an oxidizer distribution device according to the invention, in an open position. Fig.3 [ ] is an axial view representing a movable shutter of an oxidizer distribution device according to the invention. Fig. 4a [ ] is a 3D view representing a movable shutter of a fuel distribution device according to the invention. Fig. 4b ] is a cross-sectional profile view representing a movable shutter of a fuel distribution device according to the invention. DETAILED DESCRIPTION

[0012] With reference to the [ Fig.1The invention relates to a burner 1 for an industrial furnace extending along a principal axis X, comprising a fuel supply assembly and an oxidizer supply assembly. In this description, the terms upstream and downstream refer to the gas flow within the burner in normal operating conditions, and the terms axial, radial, and tangential refer to a cylindrical reference frame with axis X. The fuel supply assembly comprises, from upstream to downstream, an inlet manifold 2 configured to receive fuel, a fuel distribution device 3 configured to allow or block fuel flow and control fuel flow, and a fuel injection device 4 configured to inject fuel into the furnace.The oxidizer supply assembly includes an oxidizer inlet manifold 5 configured to receive the oxidizer, an oxidizer distribution device 6 configured to allow or block the circulation of oxidizer, as well as to control an oxidizer flow rate, and an oxidizer injection device 7, configured to inject oxidizer into the furnace.

[0013] With reference to figures 2a, 2b, the oxidizer distribution device 6 includes a movable shutter 8, through which a first opening 9 is provided, a stator 10 through which a second opening 11 is provided, a drive shaft 12 extending along the main axis X integral with the movable shutter 8 and capable of rotating the movable shutter 8.The movable shutter 8 is located opposite the stator 10, in contact with the stator 10, such that, when the movable shutter 8 is driven in rotation by the drive shaft 12, the first opening 9 is positioned at least partially opposite the second opening 11 so as to create an oxidant passage putting into fluidic communication the oxidant intake manifold 5 and the oxidant injection device 7, the first opening 9 and the second opening 11 being shaped so that the oxidant passage has a cross-section with a surface area that varies according to the angular position of the drive shaft 12.

[0014] The fuel distribution device 3 includes a fixed element 13 defining a cavity comprising an inlet connected to the fuel intake manifold 2, an outlet connected to the fuel injection device 4, and a second movable shutter 16 rotatably mounted in the fixed element 13. The second movable shutter 16 includes a wall defining a cavity opening at the outlet in the fuel injection device 4, the wall closing the inlet of the fixed element 13. A light 18 is provided through the wall so as to form a lateral opening of the movable shutter 16.The second movable obturator 16 is connected to the drive shaft 12 in such a way that, when the drive shaft 12 is driven in rotation, the opening 18 is positioned partially opposite the inlet of the fixed element 13 so as to create a fuel passage connecting the intake manifold 2 and the fuel injection device 4, the opening 18 and the inlet being shaped so that the fuel passage has a cross-section with a variable surface area depending on the angular position of the drive shaft 12.

[0015] Such a configuration allows the fuel and oxidizer flow rates to be changed simultaneously using the same actuator, greatly limiting the number of moving components and the size of the fuel supply assembly and the oxidizer supply assembly.

[0016] Advantageously, with reference to the [ Fig.3The movable shutter 8 comprises a first disk along axis X through which the first opening 9 is formed, and the stator 10 comprises a second disk along axis X through which the second opening 11 is formed. The first opening 9 has the shape of an angular portion of an annular element, and the second opening 11 has the shape of an angular portion of an annular element. Thus, by modifying the annular position of the drive shaft 12 to progressively align the first opening 9 and the second opening 11, a change in the angular position of the drive shaft 12 results in a linear change in the cross-sectional area of ​​the oxidizer passage. This allows for a proportional response of the increase in flow rate, and therefore of the heating power, as a function of the angular position control of the drive shaft 12.

[0017] Advantageously, the stator 10 includes a mixer 19 configured to generate turbulence in the oxidant flow and promote the mixing of the oxidant and the fuel. In the embodiment illustrated in figures 2a and 2b , the mixer 19 includes a perforated grid located at the level of the second opening 11. When the first opening 9 and the second opening 11 coincide so as to form an oxidant passage, the oxidant thus flows through the mixer 19 and the flow of the oxidant becomes turbulent.

[0018] With reference to figures 3 and 4 , the light 18 has a shape such that the projection onto a plane, in particular onto a plane passing through the principal axis X of the light 18 as represented in the [ Fig. 4b], forms an angular portion of a disk. Such a geometry allows, when changing the angular position of the drive shaft 12, an increase in the cross-sectional area of ​​the fuel passage proportional to the angular position of the drive shaft 12.

[0019] Advantageously, the angular position of the light 18 and the angular positions of the first opening 9 and the second opening 11 are configured so that the rotation of the drive shaft 12 causes a simultaneous and proportional change in the respective areas of the cross sections of the fuel passage and the oxidizer passage.

[0020] Advantageously, the drive shaft 12 includes an external sleeve 20 rotatably mounted on an internal shaft 21 and extending outward from the internal shaft 21. The internal shaft 21 extends through an opening formed by the movable shutter 8 and the stator 10 and is fixed to the movable shutter 16. The external sleeve 20 is connected to the movable shutter 8. Adjusting the relative angular position between the external sleeve 20 and the internal shaft 21 creates an offset between the angular position at which the movable shutter 8 allows oxidizer to flow and the angular position at which the movable shutter 16 allows fuel to flow. This allows for adjusting the excess air in the gas mixture injected into the burner 1.

Claims

1. A burner (1) for an industrial furnace comprising a fuel supply assembly and an oxidizer supply assembly, the fuel supply assembly comprising from upstream to downstream a fuel intake manifold (2) configured to receive fuel, a fuel distribution device (3) configured to control a flow rate of fuel, and a fuel injection device (4), configured to inject fuel into the furnace, the oxidizer supply assembly comprising an oxidizer intake manifold (5) configured to receive oxidizer, an oxidizer distribution device (6) configured to control a flow rate of oxidizer, and an oxidizer injection device (7), configured to inject oxidizer into the furnace, wherein: - the oxidizer distribution device (6) comprises a movable obturator (8) through which a first opening (9) is provided, a stator (10) through which a second opening (11) is provided, a drive shaft (12) rigidly connected to the movable obturator (8) and capable of driving the movable obturator (8) in rotation, the movable obturator (8) being located opposite the stator (10) in such a way that, when driven by the drive shaft (12), the first opening (9) is positioned at least partially opposite the second opening (11) so as to create an oxidizer passage putting the oxidizer intake manifold (5) and the oxidizer injection device (7) in fluid communication, the first opening (9) and the second opening (11) being shaped so that the oxidizer passage has a cross-sectional area that varies depending on the angular position of the drive shaft (12), - the fuel distribution device (3) comprises a fixed element (13) comprising an inlet in connection with the fuel intake manifold (2), an outlet in connection with the fuel injection device (4), a second movable obturator (16) rotatably mounted in the fixed element (13), the second movable obturator (16) comprising a wall defining a cavity opening at the outlet into the fuel injection device (4), the wall obturating the inlet of the fixed element (13), an aperture (18) being provided through the wall so as to form a lateral opening, the second movable obturator (16) being rigidly connected to the drive shaft (12) in such a way that, when the drive shaft (12) is driven in rotation, the aperture (18) is positioned partially opposite the inlet of the fixed element (13) so as to create a fuel passage putting the fuel intake manifold (2) and the cavity connected to the fuel injection device (4) in fluid communication, the aperture (18) and the inlet being shaped so that the fuel passage has a cross-sectional area that varies depending on the angular position of the drive shaft (12).

2. The burner (1) according to claim 1, wherein the first opening (9) has the shape of an angular portion of an annular element, and wherein the second opening (11) has the shape of an angular portion of an annular element.

3. The burner (1) according to one of claims 1 and 2, wherein the aperture (18) has a shape such that the projection of the aperture (18) onto a plane forms an angular portion of a disc.

4. The burner (1) according to any of the preceding claims, wherein the angular position of the aperture (18) and the angular positions of the first opening (9) and the second opening (11) are configured so that the rotation of the drive shaft (12) causes a simultaneous and proportional change in the respective cross-sectional areas of the fuel passage and the oxidizer passage.

5. The burner (1) according to any of the preceding claims, wherein the drive shaft extends along a main axis (X) of the burner, the movable obturator (8) and the second movable obturator (16) being coaxial and extending along the main axis (X).

6. The burner according to any of the preceding claims, wherein the stator (10) comprises a disc comprising an opening in which a mixer (19) is mounted comprising a perforated grid configured to generate turbulence in the flow of the oxidizer stream.

7. The burner (1) according to any of the preceding claims, wherein the drive shaft (12) comprises an outer sleeve (20) mounted in an adjustable manner on an inner shaft (21) and extending outside the inner shaft (21), the inner shaft (21) extending through an opening provided through the movable obturator (8) and the stator (10) and being fixed to the second movable obturator (16), the outer sleeve (21) being connected to the movable obturator (8).

8. The burner (1) according to claim 7, wherein the outer sleeve (20) is rotationally adjustable relative to the inner shaft (21).