EP1967794A2 - Oven with centralised flame guidance - Google Patents

Abstract

The stove has a fire chamber designed for burning solid fuels. A shell-shaped insert is arranged in the fire chamber with a passage opening (2) designed to pass the flame in a base area. The passage opening faces the base or a side of the fire chamber. The passage opening is formed centrally symmetrical, and the shell-shaped insert is partially made of fireproof ceramic glass and has walls made up of a metal.

Description

The invention relates to a furnace with a combustion chamber designed for burning solid fuel.

Such ovens are known. They are used today as stoves, but also as radiators for heating whole apartments and houses. As solid fuels nowadays increasingly compacts of granular combustible material, called pellets, are used. Accordingly, such stoves modern design also called pellet or firewood ovens. In order to give the user the pleasant appearance of an open fireplace, just in furnaces that are located in the living area, the combustion, for example, by a glass pane in the oven wall or made of fireproof glass oven door from the outside to see.

Now, especially due to the increasingly isolated homes and apartments, such as low-energy and passive houses, ever smaller heating loads for the stoves needed. In order to realize the required low heat outputs, the furnaces are temporarily operated only in partial load operation.

Especially in partial load operation, it is difficult to ensure a uniform combustion of solid fuels. An inconsistent or as a result incomplete combustion of fuels leads to a reduction of the combustion efficiency, and conversely also to an increase in polluting emissions. Another optical disadvantage of non-uniform combustion is that only smaller flame images with restless short flame are visible.

In view of the above-mentioned problems, the object of the invention is to provide an oven which enables improved and in particular more uniform combustion of the fuels.

This object is achieved by the invention by a development of the furnace of the type mentioned, which is characterized by a arranged in the furnace shell-like insert with a designed for flame passage passage opening in its bottom region, which faces the bottom or one side of the firebox.

In this case, the invention is based on the finding that a more uniform combustion, in particular of residues of still flammable flue gases, is made possible by an orderly centering of the flame effected by the passage opening of the shell-type insert. As a result of this ordered centering, the flue gases flow through the defined through-opening, wherein a thorough mixing of combustible flue gases with combustion air is brought about forcibly. With the strong mixing of the flue gases with combustion air necessary for the residual combustion of the flue gases combustion air is sufficiently available. Further, by the shape of the shell-like insert, hereinafter referred to simply as a shell for simplicity, defines a heat storage, which counteracts cooling of the combustion chamber in the region of the shell interior by the at least partially restrained for the heat loss in the area heat radiation. Otherwise, the heat generated in this area would unhindered outward in the direction of the combustion chamber inner walls radiated and initially only lead to a warming in the area of the furnace, which is remote from the firing center. Depending on whether the firing in the furnace is from bottom to top, as in most furnaces, or rather from one side, the through-opening faces the bottom or side of the furnace.

In a preferred embodiment, the passage opening is central, preferably formed symmetrically in the shell-like insert. Thus, the uniformity of the combustion can be further increased.

In a particularly preferred embodiment, the shell-like insert consists at least partially of refractory ceramic glass. Thus, the flames striking upwardly through the passage opening 2 can also be observed further in the interior of the shell. Such ceramic glasses are, for example, the ROBAX® glasses marketed by SCHOTT AG.

In a further preferred embodiment, an inner wall region of the shell-like insert is formed at least partially reflecting. Thus, heat radiation emitted by the flame in the interior of the shell can be at least partially reflected back into the interior, resulting in a lower cooling of the combustion area or a correspondingly higher temperature, which promotes afterburning of the flue gases. Another advantage is that the luminosity of the flame in the interior of the shell is increased by increased afterburning.

A simple way of achieving the reflective interior wall portions is to at least partially form the walls of the tray-like insert from metal. However, the shell remains opaque at least in those areas where it is completely made of metal.

In contrast, it is provided according to a particularly preferred embodiment that the refractory ceramic glass is at least partially mirrored on inner wall areas. Thus, on the one hand, the above-mentioned advantage of improved afterburning as well as a increased luminosity of the flame reached. On the other ceramic glass is further used as a material, so that transparent areas of the shell walls are possible.

In a further preferred embodiment, the mirroring of the ceramic glass is such that the shell wall portions are at least partially transparent during operation of the furnace, in particular. It can be thought to use glasses of the type of ROBAX ® mirrored glass-ceramics. These are manufactured, among others, for chimney windows or interior linings by SCHOTT AG. These discs are in the unfired state, the view through the disc is denied, whereas the flame is visible in the heated state through the walls. Thus, a good afterburning can be combined with a good visual appearance.

After a structurally simple embodiment of the shell-like insert is cylindrical or bowl-shaped.

On the other hand, it can also be provided that the shell walls extend obliquely to the bottom plane of the shell-like insert. Thus, different reflection angles are already used by the inclination of the shell walls, resulting in an optical improvement of the flame image. In this case, the angle of inclination of the shell walls relative to the ground plane in the range of 5 ° to 75 °, preferably 15 ° to 60 °, in particular 25 ° to 40 °. With a bowl angle of 90 ° you would again have a cylindrical insert.

In contrast, according to a particularly preferred embodiment, the shell walls are concave. Thus, in addition to the heat radiation, a focusing effect can be achieved.

In this context, it is particularly provided that the shell walls are elliptical or parabolic. Thus, on the one hand, the focusing effect can be enhanced, on the other hand, a still more attractive flame image can be obtained.

According to a particularly expedient embodiment, the shell in plan view of the passage plane of the bottom portion has a round or polygonal shape. Thus, the shell fits into most stoves fitting and is structurally simple to manufacture.

According to a further preferred embodiment, the passage opening has a round or polygonal shape. Thus, a suitably centered guidance of the flame can be achieved, wherein the edge regions of the passage opening can be uniformly heated or made to glow, resulting in a more even afterburning.

According to a particularly preferred embodiment, a border of the passage opening on an at least partially pointed to the passage opening tapered edge. The thinner the edge, the faster it can be made to glow and initiate the desired afterburning by igniting the flue gases. This effect is optimally exploited by the tapered edge.

Furthermore, the invention also relates to a shell-like insert with the features already described above.

Fig. 1 a

eine Seitenansicht eines schalenartigen Einsatzes für einen Ofen einer ersten Ausführungsform der Erfindung zeigt,

Fig. 1 b

den schalenartigen Einsatz aus Fig. 1 a in einer Draufsicht von oben zeigt,

Fig. 2a

eine Fig. 1 a entsprechende Ansicht einer zweiten Ausführungsform eines schalenartigen Einsatzes zeigt,

Fig. 2b

eine Draufsicht auf den schalenartigen Einsatz aus Fig. 2a ist,

Fig. 3a

eine Fig. 1 a entsprechende Ansicht einer dritten Ausführungsform eines schalenartigen Einsatzes zeigt,

Fig. 3b

eine Draufsicht auf den schalenartigen Einsatz aus Fig. 3a ist, und

Fig. 4

den schalenartigen Einsatz aus Fig. 3 in einer Schnittansicht zeigt.

Further advantages and details of the invention will become apparent from the following description with reference to the accompanying figures, of which

Fig. 1 a

shows a side view of a bowl-like insert for an oven of a first embodiment of the invention,

Fig. 1 b

the bowl-like insert Fig. 1 a in a plan view from above,

Fig. 2a

a Fig. 1 a shows a corresponding view of a second embodiment of a shell-type insert,

Fig. 2b

a plan view of the bowl-like insert Fig. 2a is

Fig. 3a

a Fig. 1 a shows a corresponding view of a third embodiment of a bowl-like insert,

Fig. 3b

a plan view of the bowl-like insert Fig. 3a is and

Fig. 4

the bowl-like insert Fig. 3 in a sectional view shows.

In Fig. 1 a first embodiment of a shell 1 is shown for a furnace according to the invention, wherein the furnace itself is not shown, but only the interior of the furnace is indicated by the reference numeral 10. In the furnace interior 10, a burner shell 11 is arranged, are received in the not shown pellets for burning. A provided in the bottom portion of the shell 1 through-hole 2 ensures that the flame (not shown) beats in use of the furnace substantially through the passage opening 2 and flow with their flue gases and the resulting suction and combustion gases through the opening 2 upwards. Thus, a well-defined flame path is given through the through-hole 2, which is dimensioned comparatively narrow, and the flue gases will mix strongly with the combustion gases.

How out Fig. 1 a is clearly visible, the side walls 3 extend obliquely to the bottom plane of the passage opening 2. As in particular from Fig. 1b can be better seen, the shell 1 in plan view has a substantially quadrangular shape, with four side walls 3a to 3d, which are each inclined relative to the ground in this embodiment about an angle of 30 °. This can be well recognized from the inclination of the edge 4 between the side walls 3a and 3d.

If the furnace with the shell 1 installed therein is in operation, a bordering region 6 of the through-opening 2, which forms the lower edges of the four side walls 3 a to 3 d, will firstly be heated to a higher degree or annealed. Due to the elevated temperature of the border 6 still flammable flue gases can ignite it, and provide for further combustion and thus a better combustion quality.

Of course, the material of the shell 1 must be designed fireproof. But even refractory products with poor heat conduction can be used for the shell 1. In the concrete in Fig. 1 However, the shell 1 is made of a refractory ceramic glass, so that the striking through the opening Flame 2 through the side walls 3 remains visible to the viewer, unless of course the interior 10 itself is visible from outside the furnace through about a glass wall or a glass door.

Furthermore, in this embodiment, the inner surfaces of the shell walls 3a to 3d are mirrored, but only mirrored so that the transparency of the ceramic glass is at least partially maintained, about 50%. Due to the mirroring of the inner surfaces, at least part of the inner surfaces of the side walls 3a to 3d of the shell 1 are reflected by the heat radiation emanating from the opening 2 flames and thrown back into the focal region above the passage opening 2. Thus, more heat is returned to this burning area, slows down the cooling in this burning area and achieves an improved quality of combustion. As already mentioned, on the one hand the combustion efficiency can be increased on the one hand and also environmentally harmful emissions can be reduced by achieving a more complete residual combustion of the flue gases located in this area. As already mentioned, heating of the border 6 ensures a gliding edge, which ensures that the flue gases can also ignite.

In order to achieve the advantage of heat reflection, the mirrored ceramic glass does not necessarily have to be used. Ceramic glazed surfaces or polished metal surfaces could also be used for the inner surfaces of the side walls 3a to 3d.

However, the remaining transparency in the use of the mirrored ceramic glass has the advantage that the flame in the shell area not only remains visible, but due to multiple reflections through the mirrored inner surfaces an optical multiplication of the flame image is achieved for the viewer. This pleasing to the viewer optical magnification of the flame play is all the more effective, since the design of the shell 1 in the shell interior area a more uniform and better combustion is achieved, which also increases the luminosity of the flame.

Fig. 2 shows a further embodiment of the shell 1, in which the shell 1 has a polygonal basic shape with eight side surfaces 3a to 3h. Accordingly, the Through hole 2 formed as an octagon, while in the embodiment of Fig. 1 was square. By a larger number of side walls with different solid angle to the bottom of the shell 1, the number of possible reflection surfaces is increased, which still further reflection possibilities are given and a more impressive flame performance for the viewer results, provided the material for the shell 1, as well as in this Embodiment preferred, consists of the mirror glass described above.

Fig. 3 shows a third embodiment of a shell 1. In contrast to those in the FIGS. 1 and 2 described embodiments, the side surfaces 3 do not form a slope 4 with the bottom plane, but a side curved edge 5, which provides a concave shell shape. In the in Fig. 3 In the embodiment shown, the shape of the curvature is elliptical. But it could also be used a parabolic shape. Due to the concave curvature of the shell wall 3, an additional focus effect of reflected from the reflective inner surface 5a heat radiation results, so that in the interior of the shell 1 above the through hole 2 can form even hotter areas, the improved afterburning of the flowing through the through-hole 2 flue gases enable. This form is opposite to the in Fig. 1 and Fig. 2 shown forms with oblique side walls again preferred.

In Fig. 4 is the shell 1 off Fig. 3 enlarged again and shown in cross section. It can be clearly seen that the border 6 of the through hole 2 tapers to the passage opening in the form of a sharp edge 7. This can be achieved simply by the edge of the border 6 is bevelled. The tapered edge 7 can be made to glow faster again faster to ignite the flue gases flowing past it faster and initiate the desired afterburning.

That on the basis of FIGS. 1 to 4 Further explained flame centering, combustion and mirroring principle can be used in all commercial dish burners and combustion systems with a guided flame. But it must not burn pot 11 as in Fig. 1a be shown present, on which the shell 1 is supported. Rather, the shell 1 in any other way above the ground the furnace 10 of a furnace, for example, by a metal frame for receiving the shell.

Also, the invention is not limited to the illustrated embodiments. Rather, the features of the invention disclosed in the above description and in the claims, both individually and in any combination for the realization of the invention in its various embodiments may be essential.

Claims (15)

Furnace having a combustion chamber (10) designed for burning solid fuels,
characterized by a bowl-like insert (1) arranged in the firebox (10) with a passage opening (2) designed for flame passage in its bottom area, which faces the bottom or one side of the firebox (10). Oven according to claim 1, characterized in that the passage opening (2) is formed centrally, preferably symmetrically, in the bowl-like insert (1). Oven according to claim 1 or 2, characterized in that the shell-like insert (1) consists at least partially of refractory ceramic glass. Oven according to one of claims 1 to 3, characterized in that an inner wall region (5a) of the shell-like insert (1) is formed at least partially reflective. Oven according to claim 4, characterized in that the walls (3) of the shell-like insert (1) are at least partially formed of metal. Oven according to one of claims 3 to 5, characterized in that the refractory ceramic glass is at least partially mirrored on inner wall regions (5a). Oven according to claim 6, characterized in that the mirroring of the ceramic glass is such that the shell wall regions (3) are at least partially transparent when the furnace is operated, in particular. Oven according to one of the preceding claims, characterized in that the shell-like insert (1) is cylindrical or bowl-shaped. Oven according to one of claims 1 to 7, characterized in that the shell walls (3) extend obliquely to the bottom plane of the shell-like insert (1). Oven according to one of claims 1 to 8, characterized in that the shell walls (3) are concave. Oven according to claim 10, characterized in that the shell walls (3) are elliptical or parabolic. Oven according to one of the preceding claims, characterized in that the shell (1) in plan view of the passage plane (2) of the bottom portion has a round or polygonal shape. Oven according to one of the preceding claims, characterized in that the passage opening (2) has a round or polygonal shape. Oven according to one of the preceding claims, characterized in that a border (6) of the passage opening (2) has an edge (7), which tapers at least partially pointedly onto the passage opening (2). Cup-like insert (1) for arrangement in a combustion chamber (10) of a furnace designed for combusting solid fuels, with a passage opening (2) designed for flame passage in the bottom area of the insert (1), in particular with further features specified in one of claims 2 to 14 of the insert (1).

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