Heating device comprising air injection rails

Abstract

The invention relates to a heating appliance comprising a combustion chamber (12) having a base (12.1), side walls (12.2, 12.3, 12.5), and a top opening (14) closed by at least one removable plate (16). The heating appliance is characterized in that it includes at least one air circuit for supplying the combustion chamber (12) with air, comprising at least one air injection manifold (32, 32') having injection orifices opening into the combustion chamber (12). The presence of at least one air injection manifold (32, 32') allows for better control of the air supply required for combustion, thereby optimizing combustion and consequently reducing the amount of unburned particles in the combustion products and increasing the thermal efficiency of combustion.

Description

[0001] The present application relates to a heating apparatus comprising at least one air injection ramp.

[0002] Document EP-867662 describes a double-hearth fireplace which has a combustion chamber comprising an upper opening closed by two removable plates. According to this embodiment, the first hearth is positioned on the removable plates and the second hearth is positioned in the combustion chamber, under the removable plates.

[0003] Regarding the combustion chamber, the air required for the combustion of the fuel enters the combustion chamber via the upper opening, which is not completely obstructed by the two removable plates. In fact, the removable plates and the perimeter of the upper opening are configured so that there is a gap between the two removable plates and between the removable plates and the perimeter of the opening.

[0004] Around at least a portion of the side walls of the combustion chamber, a first casing is provided. The space between the side walls and the first casing is intended for the circulation of combustion products from the combustion chamber to an exhaust duct. According to one configuration, the right and left side walls of the combustion chamber are spaced from the front side wall so as to create two lateral exhaust openings. Thus, the combustion products are evacuated from the combustion chamber via these lateral exhaust openings, then they travel to the rear of the right and left side walls of the combustion chamber to reach the exhaust duct positioned at the rear of the rear side wall of the combustion chamber.

[0005] A second envelope is provided around the first envelope, a space between the first and second envelopes being provided for the circulation of air from the room to be heated.

[0006] To reduce the amount of unburned material in the discharged combustion products, the rear wall of the combustion chamber includes a direct discharge opening that directly connects the combustion chamber and the discharge duct. Depending on the spacing between the removable plates, a re-ignition of the fumes is obtained at the direct discharge opening, which reduces the amount of unburned material and increases the thermal efficiency of the combustion chamber.

[0007] Document FR-2947037 proposes a solution aimed at further reducing the quantity of unburned material and increasing thermal efficiency. According to this document, two air introduction ducts are positioned at each of the lateral exhaust openings. Each duct is positioned vertically and comprises a plurality of orifices. These air introduction ducts, positioned on the combustion product exhaust path, make it possible to relight a greater quantity of combustion products and therefore reduce the quantity of unburned material and increase thermal efficiency.

[0008] Regardless of the embodiment, the direct exhaust port or air introduction ducts are used to optimize post-combustion.

[0009] In the field of stoves, documents US787014 and US2001022943 are known. According to document US 787014, the stove comprises an enclosure with a combustion chamber at the bottom, topped with a flue for evacuating the burnt gases. The enclosure has a perforated bottom wall for supplying air for the main combustion and a ramp for injecting air between the combustion chamber and the evacuation flue to ensure post-combustion.

[0010] According to document US2001022943, the stove comprises an enclosure, with a combustion chamber at the bottom in which a movable flap is positioned, above the combustion chamber, to define two paths for the combustion gases. As before, the air intended for the main combustion is supplied from the bottom of the combustion chamber. The stove also includes an air injection ramp to initiate post-combustion when the flap is in the open position.

[0011] Regardless of document US787014 or US2001022943, the air supply for the main combustion is achieved via openings provided at the level of the lower wall. This configuration is not optimal because the openings can be partially or completely blocked by the ash generated by the combustion.

[0012] Document US4249509 A is also relevant to the present invention. It discloses a heating apparatus comprising a primary air injection ramp in the lower part of the combustion chamber, and a second chamber for post-combustion.

[0013] The present invention aims to remedy all or part of the drawbacks of the prior art by proposing a solution which improves combustion.

[0014] To this end, the invention relates to a heating device comprising: a combustion chamber which has a bottom, side walls and an upper opening closed by at least one removable plate, a first circuit configured to convey combustion products from the combustion chamber to an exhaust duct.

[0015] According to the invention, the heating appliance comprises at least one air circuit for supplying the combustion chamber with air, comprising at least two air injection rails. Each injection rail comprises one or more sections comprising the injection orifices, opening into the combustion chamber, separated from each other by a distance less than or equal to 5 cm, and extending over at least 30% of the perimeter of the combustion chamber.

[0016] The presence of at least two air injection rails allows better control of the air supply required for combustion, which optimizes combustion and therefore reduces the quantity of unburned matter in the combustion products and increases the thermal efficiency of combustion.

[0017] Other characteristics and advantages will emerge from the description of the invention which follows, a description given by way of example only, with reference to the appended drawings, among which: There figure 1 is a perspective view of a heating apparatus without a top plate which illustrates one embodiment of the invention, The figure 2 is a section along plane P2 of the figure 1 , there figure 3 is a section along plane P3 of the figure 1 , there figure 4 is a perspective view of an air circuit which illustrates one embodiment of the invention, the figure 5 is a perspective view from another orientation of the air circuit visible on the figure 4 , THE figures 6A à 6B are schematic top view representations of a combustion chamber that illustrate different configurations of an air injection rail, the figure 6D is a schematic representation of an air injection ramp which illustrates one embodiment, the figure 7 is a schematic representation of an air circuit equipped with regulation systems, the figure 8A is a front view of a control system which illustrates an embodiment of the invention, the figure 8B is a section of a control system which illustrates an embodiment of the invention, the figure 9 is a top view of a heater that illustrates a top plate according to one embodiment, the figure 10 is a bottom view of a first removable plate which illustrates an embodiment of the invention, the figure 11 is a section of a second removable plate which illustrates one embodiment, the figure 12 is a section along line XII-XII of the figure 9 which illustrates a rim of the top plate and an edge of the first removable plate, the figure 13 is a section along line XIII-XIII of the figure 9 which illustrates a rim of the top plate and an edge of the second removable plate, the figure 14 is a section of one edge of the second removable plate, the figure 15 is a section of one edge of the first removable plate, and the figure 16 is a longitudinal section of a rim of the upper plate.

[0018] On the figures 1 à 3 And 9 , a heating appliance is shown at 10 which has a combustion chamber 12. By way of example, such a heating appliance is intended to be positioned in a room, more particularly in a fireplace.

[0019] According to the invention, the combustion chamber 12 has a bottom 12.1, side walls 12.2 to 12.5 and an upper opening 14 closed by at least one removable plate 16 (visible in dotted lines on the figure 3 and in solid line on the figure 9 ). Thus, the heating appliance 10 comprises two hearths, a first hearth 18.1 in the combustion chamber 12, under the removable plate(s) 16, and a second hearth 18.2, outside the combustion chamber 12, above the removable plate(s) 16.

[0020] According to one embodiment, the combustion chamber 12 has a parallelepiped shape and has a front side wall 12.2, a rear side wall 12.3, a right side wall 12.4 and a left side wall 12.5.

[0021] The heating appliance 10 comprises a conduit 20 for discharging the combustion products generated during combustion of a fuel, in particular wood, in the combustion chamber 12.

[0022] Preferably, the heating apparatus 10 comprises at least one combustion product treatment system and / or a heat exchanger.

[0023] According to the invention, the heating appliance 10 comprises a first casing 22 around the combustion chamber 12 and spaced apart from at least a portion of the side walls 12.2 to 12.5 of the combustion chamber 12 so as to form a first circuit 24 for the circulation of the combustion products from the combustion chamber 12 to the exhaust duct 20.

[0024] According to one embodiment, only the rear, right and left side walls 12.3 to 12.5 are spaced from the first casing 22. Thus, the first circuit 24 has a U-shape, seen from above, and has a central portion 24.1, positioned between the rear side wall 12.3 and the first casing 22, a right portion 24.2, positioned between the right side wall 12.4 and the first casing 22, and a left portion 24.3 positioned between the left side wall 12.5 and the first casing 22. According to one configuration, the right and left side walls 12.4, 12.5 of the combustion chamber 12 are spaced from the front side wall 12.2 so as to create two lateral discharge openings 26, 26' which communicate with the right and left portions 24.2, 24.3 of the first circuit 24. In addition, the central portion 24.1 of the first circuit 24 communicates with the evacuation duct 20 which is positioned above the central portion 24.1 of the first circuit 24, centered relative to the right and left portions 24.2, 24.3. Thus, the combustion products are evacuated from the combustion chamber 12 via these lateral evacuation openings 26, 26'. They then travel to the rear of the right and left side walls 12.4, 12.5, then to the rear of the rear side wall 12.3 of the combustion chamber 12 to reach the evacuation duct 20 positioned at the rear of the rear side wall 12.3 of the combustion chamber 12.

[0025] According to one embodiment, the heating apparatus 12 comprises a second casing 28 positioned around the first casing 22 and spaced from the first casing 22 so as to form between the first and second casings 22, 28 a second circuit 30 for the circulation of the air of the room to be heated.

[0026] According to this embodiment, the first and second circuits 24, 30 form a heat exchanger, the first casing 22 ensuring a heat transfer between the combustion products and the air in the room to be heated.

[0027] According to one configuration, the apparatus comprises a first system for treating the combustion products in the form of an orifice 31 passing through the rear side wall 12.3, directly connecting the combustion chamber 12 and the central portion 24.1 of the first circuit 24 itself directly connected to the evacuation duct 20. This first system for treating the combustion products, in the form of an orifice, can be omitted taking into account the improvement in combustion provided by the invention.

[0028] According to one embodiment, the front, rear, right and left side walls 12.2 to 12.5 are formed from bricks made of refractory material.

[0029] The first and second envelopes 22, 28, the first combustion product treatment system are not further detailed because they may be identical to those described in documents EP-867622 and FR-2947037 of the prior art.

[0030] According to a characteristic of the invention, the heating appliance 10 comprises a system for supplying air to the combustion chamber.

[0031] This supply system comprises at least one air injection ramp 32 which has a plurality of orifices 34 opening into the combustion chamber 12, to supply it with air for the main combustion in particular. Each air injection ramp 32 comprises one or more sections comprising injection orifices 34 separated from each other by a distance less than or equal to 5 cm, the sections of the same air injection ramp 32 extending over at least 30% of the perimeter of the combustion chamber 12.

[0032] According to a first example illustrated by the figure 6A , the air injection ramp 32 comprises two sections T1 and T2 which extend over two side walls representing at least 30% of the perimeter of the chamber 12.

[0033] According to a second example illustrated by the figure 6B , the air injection ramp 32 comprises a first section T3 which extends over the entire length of the rear side wall 12.3, a second section T4 which extends over a portion of the length of the right side wall 12.4 and a third section T5 which extends over a portion of the length of the left side wall 12.5.

[0034] For the present application, the length of a side wall corresponds to the dimension of the side wall taken in a substantially horizontal plane.

[0035] According to a third example illustrated by the figure 6B , the air injection ramp 32 comprises, on each of the side walls 12.2 to 12.5, two sections referenced T6 to T13.

[0036] Preferably, at least one section of at least one air injection rail 32 (preferably all sections) is integrated into the rear side wall 12.3, the right side wall 12.4 and / or the left side wall 12.5. Thus, no element of the air injection rail 32 projects into the combustion chamber 12, which increases the robustness of the device. According to one configuration, the air injection rail 32 is flush with the inner face of the rear side wall 12.3, the right side wall 12.4 and / or the left side wall 12.5.

[0037] At least one section of the air injection rail 32 is positioned between the combustion chamber 12 and the first circuit 24 for the combustion products. This configuration makes it possible to preheat the air injected into the combustion chamber 12.

[0038] In order to obtain a significant improvement, the section(s) of an air injection ramp 32 extend(s) over at least 80% of the perimeter of the combustion chamber 12.

[0039] The injection ports 34 of an air injection rail 32 may all have the same passage section or have different passage sections, as illustrated in the figure 6D . The injection orifices 34 may have passage sections in the form of a slot, circular, oblong, triangular or other. As illustrated in the figure 6D , the injection orifices 34 of an air injection ramp 32 may have a regular or irregular pitch.

[0040] Depending on the method of implementation on the figures 4 et 5 , the air injection ramp 32 extends around the entire circumference of the combustion chamber 12 and comprises injection orifices 34 distributed around the entire circumference of the combustion chamber 12, with a regular pitch of the order of 15 to 40 mm, a circular passage section of the order of 0.6 to 10 mm. However, the injection orifices 34 may be distributed with a non-regular pitch.

[0041] According to a preferred configuration, the injection orifices 34 have a passage section, a positioning and / or a pitch determined so as to obtain substantially homogeneous injected air flows around the entire perimeter of the combustion chamber 12.

[0042] According to another characteristic, each air injection ramp 32 is positioned in a substantially horizontal plane.

[0043] The combustion chamber 12 comprises at least one air injection ramp 32 positioned at a height less than or equal to 0.75 times the height of the combustion chamber 12, from the bottom 12.1 of the combustion chamber 12. The height corresponds to the dimension of the side walls taken in a substantially vertical plane. For example, for a tank with a height of the order of 31 cm, the air injection ramp 32 is located at a distance from the bottom less than or equal to 23 cm. Preferably, the air injection ramp 32 is positioned approximately at mid-height or slightly above mid-height.

[0044] According to the invention, the combustion chamber 12 comprises two air injection ramps 32, 32', a first air injection ramp 32, positioned between 0.4 and 0.75 times the height of the combustion chamber 12 from the bottom 12.1 of the combustion chamber 12, and a second air injection ramp 32' attached to the bottom 12.1 of the combustion chamber.

[0045] The orifices 34 of the second air injection ramp 32' are spaced from the bottom 12.1 of the combustion chamber 12 so as to prevent them from being blocked by ash.

[0046] The presence of at least two air injection ramps 32, 32' allows better control of the air supply necessary for combustion, which makes it possible to optimize combustion and consequently to reduce the quantity of unburned matter in the combustion products and to increase the thermal efficiency of combustion.

[0047] According to one embodiment, each air injection ramp 32, 32' comprises at least one hollow tube with a square or rectangular section which has a thickness substantially equal to that of the side walls 12.2 to 12.5. Thus, each injection ramp 32, 32' is integrated into the side walls 12.2, 12.5 of the combustion chamber 12. According to this embodiment, each side wall 12.2 to 12.5 comprises, in the lower part, a first tube of square or rectangular hollow section which forms the second air injection ramp 32'; a first row of bricks 36, of at least one brick made of refractory material, positioned above the second air injection ramp 32'; a second tube of square or rectangular hollow section which forms the first air injection ramp 32, positioned above the first row of bricks 36; and a second row of bricks 38, of at least one brick made of refractory material, positioned above the first injection ramp 32.

[0048] According to this embodiment, the lateral discharge openings 26, 26' are delimited at the top and bottom by the first and second air injection ramps 32, 32'. Thus, for each lateral discharge opening 26, 26', the first air injection ramp 32 comprises a lower face of which a zone 40, 40' forms the upper edge of the discharge opening 26, 26', the second air injection ramp 32' comprising an upper face of which a zone 42, 42' forms the lower edge of the discharge opening 26, 26'.

[0049] According to one configuration, the heating appliance 10 comprises, at at least one of the lateral discharge openings 26, 26', a second system for treating the combustion products. According to one embodiment, for each lateral discharge opening 26, 26, each second system for treating the combustion products comprises at least one air injection orifice 44, 46, at at least one of the first or second air injection ramps 32, 32', oriented towards the lateral discharge opening 26, 26'.

[0050] According to one embodiment, for each lateral discharge opening 26, 26', the zone 40, 40' of the first air injection ramp 32 comprises an orifice 44 opening at the lateral discharge opening 26, 26' and the zone 42, 42' of the second air injection ramp 32' comprises an orifice 46 opening at the lateral discharge opening 26, 26'.

[0051] Regardless of the embodiment, the first circuit 24 of the combustion products comprises at least one lateral discharge opening 26, 26' which passes through one of the side walls 12.2 to 12.5 of the combustion chamber and which is adjacent to at least one air injection ramp 32, 32'. At least one of the air injection ramps 32 adjacent to the lateral discharge opening 26, 26' comprises at least one orifice 44, 46 opening into the lateral discharge opening 26, 26' for injecting air in order to ensure treatment of the combustion products. Thus, the same air injection ramp 32 injects the air intended for the main combustion and for the post-combustion.

[0052] According to an embodiment visible on the figures 4 et 5 , each 32 (or 32') air injection ramp includes: two longitudinal tubes 48, 50 (or 48', 50') parallel to each other, configured to be positioned at the right and left side walls 12.4, 12.5, a first transverse tube 52 (or 52') connecting the longitudinal tubes 48, 50 (or 48', 50') at their first ends, configured to be positioned at the front side wall 12.2, a second transverse tube 54 (or 54') connecting the longitudinal tubes 48, 50 (or 48', 50'), parallel to the first transverse tube 52 (or 52'), offset relative to the second ends of the longitudinal tubes 48, 50 (or 48', 50') and configured to be positioned at the rear side wall 12.3.

[0053] The heating apparatus comprises at least one air circuit 56 (or 56') for supplying the combustion chamber 12 with air which comprises, in addition to the air injection ramp 32 (or 32'), a third transverse tube 58 (or 58'), parallel to the first and second transverse tubes 52, 54 (or 52', 54'), connecting the longitudinal tubes 48, 50 (or 48', 50') at their second ends, configured to be positioned between the first and second casings 22, 28 and supplied with air, said circuit 56 (or 56') comprising at least one air supply orifice.

[0054] According to one configuration, each circuit 56 (or 56') comprises first and second air supply ports 60, 62 (or 60', 62') provided at the ends of the third transverse tube 58 (or 58') and / or a third air supply port 64 (or 64') provided equidistant from the ends of the third transverse tube 58 (or 58').

[0055] Each air circuit 56, 56' is configured to obtain air flows injected through the injection orifices 34 that are substantially homogeneous around the entire perimeter of the combustion chamber 12.

[0056] According to one embodiment, each air circuit 56, 56' comprises at least one pipe 66.1 to 66.3 configured to connect each supply port 60, 62, 64 to an air supply A which may be unique.

[0057] Each duct 66.1 to 66.3 may comprise an air flow regulation system 68.1 to 68.3, for example in the form of a register or a diaphragm. According to a preferred embodiment visible on the figure 8A , each air circuit 56, 56' comprises at least one air flow regulation system 68.1 to 68.3 in the form of a diaphragm. The latter makes it possible to adjust the air flow more precisely and centered relative to the pipe 66.1 to 66.3. On the figure 7 , the air flow regulation systems 68.1 to 68.3 are arranged upstream of the supply orifices 60, 62, 64. Alternatively, they could be arranged downstream.

[0058] According to a configuration illustrated by the figure 8B , each air flow regulation system 68.1 to 68.3 could be associated with an air flow straightening system 70 so that the channeled air flow 72 is as swirl-free as possible. According to one embodiment, each straightening system 70 is positioned downstream of the regulation system and is in the form of a plate 74 closing the duct 66.1 to 66.3 and having a multitude of through holes 76. Of course, the invention is not limited to this positioning for the air flow straightening system 70. Alternatively, an air flow straightening system 70 could be positioned in each of the ramps so that the channeled air flow 72 is as swirl-free as possible. The presence of this straightening system 70 makes it possible to manage the channeled air flow 72 more precisely.

[0059] The heating apparatus 10 comprises an upper plate 78 which has a rim 80 delimiting the upper opening 14 of the combustion chamber 12.

[0060] According to one feature, the rim 80 of the upper plate 78 and each removable plate 16 are configured to limit air leakage between the inside and the outside of the combustion chamber 12 when each removable plate 16 is in the closed position.

[0061] According to an embodiment visible on the figure 9 , this upper opening 14 is closed by a first removable front plate 16 and a second removable rear plate 16'.

[0062] Advantageously, the rim 80 of the upper plate 78 and each front and rear removable plate 16, 16' are configured to limit the passage of air between the two front and rear removable plates 16, 16' and between each of the front or rear removable plates 16, 16' and the rim 80 of the upper plate 78 when the two front and rear removable plates 16, 16' are in the closed position, as illustrated in the figure 9 .

[0063] The edge 80 of the upper plate 78 has a front side 80.1, a right side 80.2, a left side 80.3 and a rear side 80.4.

[0064] The front removable plate 16 comprises a front edge 16.1, a right edge 16.2, a left edge 16.3 configured to cooperate respectively with the front side 80.1, the right side 80.2, the left side 80.3 of the rim 80 of the upper plate 78 as well as a rear edge 16.4 configured to cooperate with the front edge 16.1' of the rear removable plate 16'. The latter also comprises a right edge 16.2', a left edge 16.3' and a rear edge 16.4' configured to cooperate respectively with the right side 80.2, the left side 80.3 and the rear side 80.4 of the rim 80 of the upper plate 78.

[0065] According to one embodiment, several seals are provided between the rear edge 16.4 of the front removable plate 16 and the front edge 16.1' of the rear removable plate 16', and between the other edges of the front and rear removable plates 16, 16' and the four sides of the rim 80 of the upper plate 78.

[0066] As illustrated by the figure 12 , the front edges 16.1, right 16.2 and left 16.3 of the front removable plate 16 have complementary shapes with the front sides 80.1, right 80.2, left 80.3 of the rim 80 of the upper plate 78.

[0067] The right 16.2', left 16.3', rear 16.4' edges of the rear removable plate 16' have shapes complementary to the right 80.2, left 80.3 and rear 80.4 sides of the rim 80 of the upper plate 78, as illustrated in the figure 13 .

[0068] The rear edge 16.4 of the front removable plate 16 has complementary shapes with the front edge 16.1' of the rear removable plate 16', as illustrated in the figure 15 .

[0069] For the present application, two elements have complementary shapes when there remains a small gap between them when they cooperate.

[0070] According to one embodiment, the front 16.1, right 16.2 and left 16.3 edges of the front removable plate 16 comprise projecting ribs 82 configured to cooperate with recessed grooves 84 provided at the front 80.1, right 80.2, left 80.3 sides of the rim 80 of the upper plate 78. The right 16.2', left 16.3', rear 16.4' edges of the rear removable plate 16' comprise projecting ribs 86 configured to cooperate with recessed grooves 88 provided at the right 80.2, left 80.3 and rear 80.4 sides of the rim 80 of the upper plate 78. The rear edge 16.4 of the front removable plate 16 comprises a projecting rib 90 configured to cooperate with a recessed groove 92 provided at the edge front 16.1' of the rear removable plate 16'. This embodiment allows to increase the escape path.

[0071] The front removable plate 16 is configured to be moved back and forth to adjust its gap with the rear removable plate 16'.

[0072] To facilitate its guidance, the front removable plate 16 comprises, at its lower face (facing towards the inside of the combustion chamber in operation), a right longitudinal boss 94 and a left longitudinal boss 94' configured to slide against respectively the right side 80.2 and the left side 80.3 of the edge 80 of the upper plate 78.

[0073] The front edge 16.1 of the front removable plate 16 and the front side 80.1 of the rim 80 of the upper plate 78 each have an inclined face 96, 96' to facilitate the passage of the front removable plate 16 above the rim 80 of the upper plate 78 when said front removable plate 16 is moved away from the rear removable plate 16'.

[0074] The right and left sides 80.2, 80.3 of the rim 80 of the upper plate 78 each comprise a recessed notch 98. In addition, the front plate 16 comprises, at its lower face, a right transverse boss 100 and a left transverse boss 100' configured to cooperate with the recessed notches 98 provided at the right and left sides 80.2, 80.3 of the rim 80 of the upper plate 78 when the front removable plate 16 is in the closed position. When the front removable plate 16 is no longer in the closed position, the transverse bosses 100, 100' slide along the right and left sides 80.2, 80.3 of the rim 80 of the upper plate 78 so as to cause a slight lifting of the front removable plate 16.

[0075] These removable plates 16, 16' and / or the upper plate 78 can be molded and machined subsequently to improve the sealing, the sliding of the removable plates 16, 16' and reduce the noise during their sliding.

Claims

1. Heating apparatus having a combustion chamber (12) that has a bottom (12.1), lateral walls (12.2 to 12.5) and an upper opening (14) closed off by at least one removable plate (16), the heating apparatus also having a first circuit (24) configured to convey combustion products from the combustion chamber (12) to an exhaust duct (20), the heating apparatus comprising: - at least one air circuit (56, 56') for supplying the combustion chamber (12) with air and having at least two air injection manifolds (32, 32') comprising one or more segments comprising injection orifices (34), which open into the combustion chamber (12), are separated from one another by a distance of less than or equal to 5 cm, and extend over at least 30% of the periphery of the combustion chamber (12), - a first enclosure (22) around the combustion chamber (12), said first enclosure (22) being spaced apart from at least some of the lateral walls (12.2 to 12.5) of the combustion chamber (12) so as to form the first circuit (24) for circulating combustion products from the combustion chamber (12) to the exhaust duct (20), the combustion chamber (12) comprising the first air injection manifold (32), positioned between 0.4 and 0.75 times the height of the combustion chamber (12) from the bottom (12.1) of the combustion chamber (12), and the second air injection manifold (32') positioned adjoining the bottom (12.1) of the combustion chamber, the orifices (34) of said second air injection manifold being spaced apart from the bottom (12.1) of the combustion chamber (12).

2. Heating apparatus according to Claim 1, characterized in that the combustion chamber (12) has a parallelepipedal shape and has a front lateral wall (12.2), a rear lateral wall (12.3), a right-hand lateral wall (12.4) and a left-hand lateral wall (12.5) and in that only the rear, right-hand and left-hand lateral walls (12.3, 12.4, 12.5) are spaced apart from the first enclosure (22).

3. Heating apparatus according to Claim 1 or 2, characterized in that the first combustion product circuit (24) comprises at least one lateral exhaust opening (26, 26') that passes through one of the lateral walls (12.2 to 12.5) of the combustion chamber (12) and that is adjacent to at least one air injection manifold (32, 32'), at least one of the air injection manifolds (32, 32') adjacent to the lateral exhaust opening (26, 26') comprising at least one orifice (44, 46) opening into the lateral exhaust opening (26, 26') in order to inject air for treating the combustion products.

4. Heating apparatus according to one of the preceding claims, characterized in that at least one segment of at least one air injection manifold (32) is integrated into at least one of the lateral walls (12.3, 12.4, 12.5).

5. Heating apparatus according to one of the preceding claims, characterized in that the segment (or segments) of each air injection manifold (32, 32') extend(s) over at least 80% of the periphery of the combustion chamber (12).

6. Heating apparatus according to the preceding claim, characterized in that each air injection manifold (32, 32') extends over the entire periphery of the combustion chamber (12) and comprises injection orifices (34) distributed over the entire periphery of the combustion chamber (12), with a regular spacing of the order of 15 to 40 mm and a circular passage section of the order of 0.6 to 10 mm.

7. Heating apparatus according to one of the preceding claims, characterized in that each air injection manifold (32, 32') comprises at least one hollow tube with a square or rectangular section that has a thickness substantially equal to that of the lateral walls (12.2 to 12.5) of the combustion chamber (12).

8. Heating apparatus according to the preceding claim, characterized in that each lateral wall (12.2 to 12.5) comprises, from bottom to top, a first tube with a square or rectangular hollow section that forms an air injection manifold (32'), a first course of bricks (36), with at least one brick made of refractory material, a second tube with a square or rectangular hollow section that forms an air injection manifold (32), and a second course of bricks (38), with at least one brick made of refractory material.

9. Heating apparatus according to one of the preceding claims, characterized in that the air circuit (56, 56') comprises at least one air flowrate regulation system (68.1 to 68.3) in the form of an aperture.

10. Heating apparatus according to one of the preceding claims, characterized in that it comprises an upper plate (78) that has a rim (80) delimiting the upper opening (14) of the combustion chamber (12), the rim (80) and each removable plate (16, 16') being configured so as to limit air leakages between the interior and the exterior of the combustion chamber (12) when each removable plate (16, 16') is in the closed position.

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