EP1396682B1 - Heating apparatus comprising a dismountable smoke box with automatic check valve and with afterburning chamber - Google Patents

Abstract

The detachable smoke box for a solid fuel heater has three sections which are manually assembled. It has a nozzle (13) to receive the chimney (15) and a flap carrier (19) which has quick fixing mounts into a chamber in the nozzle. The flap and chamber define a post combustion volume (46). There is a blown air ramp (47) adjacent to the inlet of the post combustion chamber.

Description

The present invention relates to a solid fuel heating apparatus having a built-in automatic flapper removable smoke box.

When operating a solid fuel heater, the fire rate must be optimal to prevent the escape of a significant portion of the calories in the exhaust gas and flue gas system.

In addition, to increase the heating efficiency of the heater, the combustion gases and fumes are slowed down by various baffles in the upper part of the hearth, which also makes it possible to lengthen their path so as to recover calories which would otherwise be part of the heating system. 'atmosphere.

Furthermore, to prevent the exit of the combustion air flow and possibly the flames through the door when it is open for refueling, there are direct exhaust valves which close the section of the exhaust duct during the steady state and release it by automatically tilting when opening the door to allow the aeration flow of combustion to evacuate completely through the conduit and not through the door.

The valve is generally constituted by a flap pivoting about an axis whose ends bear on two landing surfaces fixed on the body of the discharge nozzle making the assembly difficult to dismantle.

In addition, the smoke retardation circuit develops dissociated from the central portion of the exhaust nozzle allowing neither easy access for sweeping, nor rapid disassembly and removal for cleaning and possibly replacement.

In the prior art, for example, the application FR 2,522,782A is known which describes a smoke evacuation assembly for a closed hearth. This assembly comprises an outlet nozzle fitting on the flue gas duct and projecting towards the interior of the fireplace.

It also includes a pivoting valve mounted on a support frame, closing or releasing the outlet nozzle. The state of this valve is controlled by a push rod in contact with the access door of the fireplace according to the open state of the latter.

The present inventors have already devised a particularly advantageous smoke box for a closed fireplace or stove or any other solid fuel heating apparatus, which overcomes these various disadvantages. This removable smoke box, with automatic valve and integrated heat exchanger, has been protected by the filing of a patent application in France under the number 01 14122, published with the number FR-A-2,831,650.

The smoke box described consists of three parts assembled together by simple manual installation: a nozzle receiving the exhaust duct, a valve-holder part which is engaged and assembled by a quick assembly means in a chamber nozzle receiving bottom and delimiting therewith an annular heat recovery chamber, and a pivotally mounted flap mounted on the valve member which automatically switches to the open position at the opening of the door.

The demountable character is total. Indeed, there are only three parts quickly rising into one another without any tools to form the smoke box.

The assembly and disassembly of parts are thus quick and easy both at the factory during manufacture and during periodic cleaning and sweeping. Moreover, this constructive simplification makes it possible to reduce the cost of labor and the cost price.

This constitution makes it possible to use monobloc cast iron parts providing solidity, longevity and thermal inertia. We also benefit from a compact assembly in which the evacuation is one with the smoke box.

The present invention aims to provide an improvement to this type of smoke boxes, making them even more advantageous. This object is obtained with an apparatus according to claim 1.

Fuel heaters

This earlier application, which was not published at the time of filing of this patent application, is not part of the state of the art to be taken into consideration in determining patentability. solid contain a fireplace in which the solid fuel is piled up and burned. Because of this accumulation, the combustion is generally far from complete and the fumes escaping the home still contain a significant amount of unburnt.

These unburnt products contain mainly carbon monoxide and volatile compounds derived from the distillation of solid fuels, such as wood, heated to high temperatures inside the home. They escape from the firebox into the flue gases, pass through the smoke box and are released into the atmosphere. They are therefore particularly polluting.

In addition, these unburned materials represent a large amount of potentially recoverable energy that is lost to the atmosphere without the calories being removed for heating. The efficiency of the heater is particularly reduced.

The improved smoke box of the present invention makes it possible, while retaining the advantages and characteristics mentioned above, to limit polluting discharges into the atmosphere and to increase the efficiency of the heater by recovering a maximum of calories.

For this, the improved smoke box has an afterburner chamber in which unburned materials during primary combustion inside the home, are burned in turn. Overall, the combustion of solid fuel is more complete and pollutant emissions are greatly reduced.

The calories produced during the afterburner are mostly recovered, increasing the efficiency of the heater.

Preferably, the chamber of afterburner can be shaped and arranged in the heat recovery chamber, defined between the walls of the nozzle receiving chamber and the flapper chamber of the smoke box as described above.

The post-combustion chamber, due to its central position in the upper volume above the upper wall of the firebox, radiates uniformly the heat, which allows an optimal diffusion of the recovered heat.

The particularly inventive structure and shapes of the previously claimed smokebox can be retained. Only very slight modifications are necessary to achieve this improvement.

Its advantages, in particular its completely and easily removable nature, the reduction of its manufacturing cost, the presence of an automatic valve and an integrated heat exchanger, can also be preserved in the improved smoke box according to the present invention.

• la figure 1 est une vue schématique en perspective montrant un foyer fermé équipé de la boîte à fumées selon l'invention ;
• la figure 2 est une vue en perspective de la boîte à fumées à l'état dissocié dans laquelle les différentes pièces sont décalées verticalement ;
• la figure 3 est une vue en coupe longitudinale de l'ensemble de la boîte à fumées améliorée selon l'invention ;
• la figure 4 est une vue en coupe longitudinale, similaire à celle de la figure 3, d'une autre variante de la boîte à fumées améliorée selon l'invention.

The invention will be well understood with other features and advantages which will appear in the description which follows, given by way of example and accompanied by the drawings in which:

• Figure 1 is a schematic perspective view showing a closed fireplace equipped with the smoke box according to the invention;
• Figure 2 is a perspective view of the smoke box in the dissociated state in which the different parts are offset vertically;
• Figure 3 is a longitudinal sectional view of the assembly of the improved smoke box according to the invention;
• FIG. 4 is a longitudinal sectional view, similar to that of FIG. 3, of another variant of the improved smoke box according to FIG. the invention.

The fume box according to the invention is intended to equip any solid fuel heater, without restricting its scope. It has been particularly studied for a closed fireplace.

The invention will now be described with reference to the figures, taking as an example a fireplace 1 closed hearth in the form of a box 2 closed by a glass door 3. This box 2 defines a combustion chamber 4 constituting the home in which must burning a wood fire fed through a front opening 5 closed by the door 3. The closed hearth is delimited by side walls 6 and 7, a bottom 8 and an upper wall 9.

A cover wall 10 closes the box 2 upwards leaving between it and the upper wall 9 of the hearth a recovery chamber 11 open towards the front by a front opening in the form, for example, of several front mouths such as 12 evacuating the flow of hot air into the room to be heated.

The improved smoke box according to the invention is mounted in the central position of the upper part of the closed hearth 1.

Like the flue gas box disclosed in the previous patent application, it consists of a nozzle 13 consisting of a one-piece piece of generally cylindrical tubular shape having at its upper end a tubular cylindrical section 14 in which is mounted by fitting a flue gas exhaust duct.

The body of the nozzle 13 terminates at its other end by a cylindrical portion 16 of larger diameter delimiting a receiving chamber 17. The two end portions of the nozzle are connected by a central shoulder 18.

In the reception room 17 comes mounting a valve member 19 of generally cylindrical shape. It is mounted in this receiving chamber 17 by a rapid assembly means of the type for example rapid locking said quarter turn or bayonet or any other equivalent means of rapid assembly.

This valve member 19 has a tubular body of generally cylindrical shape, the lower edge is shaped as a ring 20 for slowing down and maintaining protruding outwardly peripheral projection.

This ring 20 has an alternating structure of solid parts 21 and empty parts 22, for example crenellated followed by notches, among which are receiving slots 25 and insertion slots 26 of larger size. The latter are intended to cooperate, for purposes of support and blocking, with support tabs 27 formed in the lower edge 29 in the ring of the nozzle 13 in the form of transverse stops continuing to protrude inwards.

The valve member 19 is continued upwardly by two notch slots 30 which are diametrically opposed and have a rounded bottom, recessed in the upper peripheral edge 31 of the valve member 19, to serve as a bearing surface at the ends 32 of the valve member. the pivot axis 33 of a valve 34.

Between these notches is formed in this valve holder part 19 a semi-circular shoulder 36 against which the valve 34 comes into closing abutment.

The valve 34 is a one-piece disc-shaped cast iron piece in two half-parts 37 and 38 of semicircular contours and of unequal dimensions, of which one part 37 is of larger diameter than the other 38 so as to introduce a dimensional dissymmetry and mass and thus create by gravity an automatic return downward tilting the valve 34 by its heavier half portion 37.

The valve 34 is hingedly mounted by a pivoting articulation 39 (FIGS. 3 and 4) pivotally actuated by the hooked end 40 of a thrust rod 41 which passes through its other end the upper front face of the apparatus for abut against the upper cross member of the glass door when it is closed or against a protrusion 42 provided opposite for this purpose.

As long as the door is closed, the mechanical contact maintains the push rod 41 and therefore the valve 34 in the closed state. When the door opens, the push rod 41 is released from its thrust stress and the valve 34 is driven downwardly by gravity, bringing it to the fully open position. This position greatly limits the risk of flames coming back through the front door of the fireplace.

It will be understood that the forms described allow easy assembly and disassembly of the smoke box, by a simple manual operation requiring no tools.

The space delimited by the shoulder 18 of the nozzle 13, the concentric walls of the receiving chamber 17 and the valve member 19 constitute an annular recovery chamber 43 in which there is a slowing down of the fumes and an exchange of heat. It communicates from below with the hearth by the crenellated crown 20 and from above with the discharge duct 15 through an exhaust gap 44 existing between the shoulder 18 of the nozzle 13 and the upper edge of the door piece. -clapet 19.

According to an essential characteristic of the present invention, this annular recovery chamber can be shaped and fitted into a post-combustion chamber 46 for unburnt materials that pass through this chamber within the combustion fumes.

In order for the complete combustion of the unburnt to take place in the afterburner chamber, two conditions must be fulfilled simultaneously: the quantity of oxygen and the temperature must be sufficient for the unburnt materials to be in combustion conditions.

When both of these conditions are met, unburnt combustion is triggered automatically in the afterburner and generates a significant amount of calories that can be recovered. The afterburner is then self-maintained, as long as there is enough material to burn and oxygen in sufficient quantity, thanks to the heat it produces.

The combustion of the solid fuel, started inside the fireplace, can end in the afterburner chamber where the unburned pollutant compounds are degraded in their turn. The polluting discharges into the atmosphere are thus considerably reduced.

To achieve these objectives, the device according to the invention comprises a blown air ramp 47 preferably disposed near the inlet 48 of the afterburner chamber located between the lower edges of the nozzle 13 and the valve holder 19. blower ramp brings fresh air to the proper temperature.

The blast ramp (47) can also be advantageously placed in the flue gas box, that is to say in the described structure located in the upper part of the firebox.

It is in the form of a tubing 49, a portion of which is shaped as a ring 50, the diameter of which preferably corresponds substantially to to that of the inlet of the annular afterburner chamber 46 or is slightly greater than this. The pipe 49 continues with a connecting portion 51 opening out of the heater.

The ring portion 50 of the tubing has orifices 52 of air distribution, preferably uniformly distributed over its entire length and oriented for example opposite the inlet 48 of the afterburner chamber. These orifices could be oriented differently, especially towards the outlet of the afterburner chamber.

The blast ramp 47 makes it possible to provide the inlet of the afterburner chamber with the additional oxygen necessary for the combustion of the unburnt, in the form of air taken outside the heating apparatus and distributed through the orifices 52. To improve the injection of air, the orifices 52 may advantageously be shaped to act as nozzles.

The air is blown at the entrance of the afterburner by a natural current or a forced flow using for example a turbine or a fan.

In order to also provide the heat input necessary to trigger the afterburner, the device comprises any means of heating the air distributed by the ramp 47 or a direct heating means of the afterburner chamber 46, comprising for example one or several electrical resistances.

According to a preferred embodiment, the air diffused by the ramp 47 is heated to a sufficient temperature. For this purpose, the connecting portion 51 of the tubing 49 preferably passes inside the combustion chamber 4 of the hearth 2 of the heating apparatus before ending up in the smoke box.

The device according to the invention may also further comprise auxiliary heating means, supplementing the heat input from the furnace and the primary combustion occurring in the combustion chamber 4, in order to reach a level of heat. sufficient to generate post-combustion.

The operation of such an auxiliary heating means may be required when the heat of the home is insufficient, especially when starting the primary combustion or when the fire decreases.

It is advantageous to imagine a control system automatically controlling the start-up and shutdown of the auxiliary heating means, for example comprising a temperature sensor placed in the afterburner chamber or upstream thereof in order to detect a possible absence afterburner.

The circulation of the air in the pipe 49, from the end opening to the outside of the heater to the ring 50 where it escapes through the orifices 52, occurs naturally due to the difference in density of hot air. It is nevertheless possible to force or accelerate this circulation, for example by means of a fan or a turbine, in order to increase the flow rate of the air blown through the orifices 52.

At their exit from the combustion chamber 4 of the combustion chamber 2, the combustion fumes containing the unburned materials pass close to the ring 50 of the air-blast ramp 47 and mix with the hot, oxygen-rich air blown through the orifices 52. The fumes then enter the afterburner chamber 46 through the inlet 48 through the empty portions 22 of the ring 20 and undergo a post-combustion.

Due to its bent shape, the afterburner chamber 46 causes a slowing of the flow of fumes before their evacuation through the exhaust duct 15. This slowing down allows the afterburner to have the time to be completely realized within the afterburner room. In addition, it makes possible a maximum heat exchange to recover the calories produced by the afterburner.

In order to amplify this heat exchange phenomenon, it is possible to further lengthen the smoke path and to multiply the heat exchange surfaces. Thus, for example, a particularly advantageous embodiment has been shown in FIG. 4. In this preferred embodiment, the shoulder 18 of the nozzle 13 is extended on its underside by a circular rim 53 extending downwards, which thus forms in the exhaust gap 44 a baffle that the fumes are forced to bypass before being able to take the exhaust duct 15.

In order to further improve the evacuation of the heat recovered in the afterburner chamber, fins 54 may advantageously be provided on the outside of the lower cylindrical portion 16 of the nozzle 13. Preferably, these fins 54 are arranged radially, at regular intervals and substantially vertically. Such fins 54 have been shown in FIGS. 3 and 4.

With the study of the figures, one will be able to notice a last possible modification with respect to the box of fumes described in the previous patent application. It relates to the positioning of the exhaust duct 15 with respect to the smoke box and more precisely with respect to the nozzle 13.

This one is no longer directly fitted at the outlet of the recovery chamber 43 transformed here into an afterburner chamber 46, but has been shifted upwards where it rests preferably on a bearing shoulder 55 formed on the inside face of the upper cylindrical section 14 of the nozzle 13.

This modification is recommended for reasons of safety, in order to prevent the end of the exhaust duct 15 from being deformed or deteriorated by the flames or the high temperatures prevailing in the afterburner chamber.

Claims (18)

1. Solid fuel heating device, comprising a removable smoke box having an integrated automatic shutter and a furnace (1), the smoke box comprising a tubular nozzle (13), on one portion of which a smoke discharge pipe (15) is fitted, and being constructed in two cylindrical portions which have different diameters and which are separated by means of a shoulder (18), comprising an upper portion (14) and a lower portion (16) having a larger diameter forming a receiving chamber (17) for the other constituent parts including an automatic shutter (34) which is held in a closed position by the door of the furnace (1) when it is in a closed position and which opens automatically by pivoting downwards when the door is opened, wherein in the heating device, the lower end of the nozzle (13) is provided with structures for fixing on the upper wall of the furnace (1), the receiving chamber (17) comprises rapid assembly means with a unitary door/shutter component (19) which is generally of cylindrical form and which forms with the nozzle (13) an annular heat-recovery chamber (43), the door/shutter component (19) engaging and being assembled so as to be retained in the receiving chamber (17) by means of a simple manual action which requires no tool, the shutter (34) has a diametrical shaft (33) whose ends (32) at the shaft end extend beyond the peripheral edge thereof in order to be pivotably supported on bearing surfaces of the door/shutter component (19), and the smoke box comprises a post-combustion chamber (46) which is formed and arranged in the heat-recovery chamber (43) defined between the walls of the receiving chamber (17) of the nozzle and the door/shutter component (19).
2. Heating device according to the preceding claim, characterised in that a blown air member (47) provides the addition of oxygen required for the post-combustion operation.
3. Heating device according to the preceding claim, characterised in that the blown air member (47) is arranged in the proximity of the inlet (48) of the post-combustion chamber.
4. Heating device according to claim 2, characterised in that the blown air member (47) is placed in the smoke box.
5. Heating device according to any one of claims 2 to 4, characterised in that the blown air member (47) is in the form of a tube (49), one portion of which is formed as a ring (50) followed by a connection portion (51) which opens at the outer side of the heating device.
6. Heating device according to the preceding claim, characterised in that the ring-like portion (50) of the tube has air distribution orifices (52).
7. Heating device according to claim 6, characterised in that the orifices (52) are distributed regularly over the entire length of the ring-like portion (50) and are orientated facing the inlet (48) of the post-combustion chamber (46).
8. Heating device according to claim 6, characterised in that the orifices (52) are orientated towards the outlet of the post-combustion chamber (46).
9. Heating device according to any one of claims 6 to 8, characterised in that the orifices (52) are formed so as to act as nozzles.
10. Heating device according to any one of claims 2 to 9, characterised in that it comprises a means for heating the air which is distributed by the member (47) or for heating the post-combustion chamber (46).
11. Heating device according to claims 4 and 10, characterised in that the connection portion (51) of the blown air member (47) extends to the inner side of the combustion chamber (4) of the furnace of the heating device before terminating in the smoke box.
12. Heating device according to claim 10 or 11, characterised in that it further comprises an additional heating means.
13. Heating device according to claim 12, characterised in that it comprises a control system which automatically controls the activation and deactivation of the additional heating means.
14. Heating device according to any one of claims 2 to 13, characterised in that it comprises a means for forcing the circulation of the air at the inner side of the blown air member (47), in particular a fan or a turbine.
15. Heating device according to any one of the preceding claims, characterised in that the shoulder (18) of the nozzle (13) is extended at the lower face thereof by means of a circular edge (53) which extends downwards, thus forming a chicane which the smoke is obliged to follow before being able to enter the discharge pipe (15).
16. Heating device according to any one of the preceding claims, characterised in that the smoke box comprises fins (54) on the outer side of the lower cylindrical portion (16) of the nozzle (13).
17. Heating device according to any one of the preceding claims, characterised in that the discharge pipe (15) is not fitted directly to the outlet of the post-combustion chamber (46) but is instead offset in an upward direction.
18. Heating device according to the preceding claim, characterised in that the smoke box comprises a support shoulder (55) which is formed on the inner face of the upper cylindrical portion (14) of the nozzle (13) and which is intended to support the discharge pipe (15).

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