EP2816283A1 - Combustion cavity and furnace with combustion cavity - Google Patents

Abstract

The invention relates to a combustion trough for pourable biomass fuel, comprising: a bottom section (2) for receiving the free-flowing biomass fuel; a wall portion (3) extending at least partially around the bottom portion (2); and at least one restriction member (4a, 4b) extending vertically from the bottom portion (2); wherein the combustion trough (1) is adapted to assume at least two operating conditions: a first operating state in which the bottom section (2) has a first bearing surface (5a) for receiving the free-flowing biomass fuel, and a second operating state in which the Bottom portion (2) has a second bearing surface (5b) for receiving the free-flowing biomass fuel, wherein the first bearing surface (5a) is greater than the second bearing surface (5b) and the second bearing surface (5b) at least partially by the at least one limiting element (4a, 4b) is limited.

Description

FIELD OF THE INVENTION

The present invention relates generally to a combustion trough and an oven having such a combustion trough.

BACKGROUND OF THE INVENTION

There are generally known stoves for heat generation, which are particularly suitable for the combustion of pourable biomass fuel, such as wood chips or pellets. Such ovens are typically also used in living quarters, e.g. set up in the form of a stove.

In principle, it is known that the pourable biomass fuel for combustion is arranged on a combustion grate in a so-called combustion trough of a furnace. The firing well typically surrounds the firing grid and forms a trough, i. a (flat) vessel to receive the biomass fuel for combustion.

It is also, for example, from the European patent application EP 2 500 650 A2 known that the combustion grate of a furnace can be designed as a so-called Kipprost. The tipping grate is rotatably mounted and can be rotated in order to tip combustion residues into an ash box arranged under the tipping grate.

The object of the present invention is to provide an improved combustion trough or an oven with such a combustion trough.

SUMMARY OF THE INVENTION

According to a first aspect, the present invention provides a combustion trough in accordance with independent claim 1. According to a second aspect, the present invention provides a furnace with a combustion trough according to the first aspect in accordance with claim 8.

Other aspects and features of the present invention will become apparent from the dependent claims, the accompanying drawings and the description below preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWING

• Fig. 1 ein Ausführungsbeispiel einer Pelletbrennmulde in Übereinstimmung mit der vorliegenden Erfindung in einer dreidimensionalen Ansicht in einem ersten Betriebszustand veranschaulicht, in dem eine erste größere Auflagefläche für die Pellets bereitgestellt ist;
• Fig. 2 die Pelletbrennmulde von Fig. 1 in einem Übergang vom ersten in einen zweiten Betriebszustand veranschaulicht; und
• Fig. 3 die Pelletbrennmulde in einem zweiten Betriebszustand veranschaulicht, in dem eine zweite Auflagefläche für die Pellets bereitgestellt ist, wobei die zweite Auflagefläche kleiner ist als die erste Auflagefläche im ersten Betriebszustand gemäß Fig. 1.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

• Fig. 1 an embodiment of a pellet burner in accordance with the present invention in a three-dimensional view in a first operating state illustrated in which a first larger bearing surface is provided for the pellets;
• Fig. 2 the pellet burner from Fig. 1 illustrated in a transition from the first to a second operating state; and
• Fig. 3 illustrates the pellet burner in a second operating state in which a second bearing surface is provided for the pellets, wherein the second bearing surface is smaller than the first bearing surface in the first operating state according to Fig. 1 ,

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the Fig. 1 to 3 an embodiment of a pellet burner 1 is illustrated in accordance with the present invention. Before a detailed description follows first general explanations to the embodiments and their advantages.

The embodiments relate to a combustion trough for pourable biomass fuel, such as e.g. Woodchips or pellets. Bulk biomass fuel here comprises shredded or molded biomass fuel which, for example, can be transported in sacks and can be portioned well for different heating power requirements. The firing well is typically configured for an oven, such as a pellet and / or wood chip oven or the like. Some embodiments, which are also discussed below, relate to an oven, such as a pellet stove or woodchip oven or the like, configured for the combustion of bulk biomass fuel and having a firebox, as described below.

The known from the prior art fuel trough has a fixed volume for Intake of pellets. If only a small amount of pellets is introduced for combustion in such known from the prior art pellet burner, it may be the heat generation during combustion is so low that the combustion is stopped. This can happen, for example, if the pellets are arranged at a small amount of pellets only one by one and without contact with each other in the pellet burner. The user of a pellet stove with such a pellet burner must therefore fill a sufficient amount of pellets in the pellet burner, so that the combustion is safely maintained and all pellets burn. However, this is undesirable since the user may only want lower heat output and / or short burn time and consequently would like to burn a smaller amount of pellet than the pellet burner well size dictates.

The combustion trough according to the embodiments of the present invention is designed to be variably variable and can provide different trough volumes. As a result, a good heat development and good combustion behavior and thus good combustion is possible even at low biomass fuel quantities.

For this purpose, the combustion trough according to the embodiments comprises a bottom section for receiving the pourable biomass fuel. The bottom portion may be configured as a flat surface on which the pourable biomass fuel is placed by an operator or an automation arranging a certain amount of the pourable biomass fuel on the bottom portion.

The firing well further includes a wall portion that extends at least partially around the bottom portion. The wall section may at least partially serve as a boundary for the biomass fuel. In some embodiments, the bottom portion and the wall portion together form a trough, i. a (flat) vessel for receiving the free-flowing biomass fuel.

In addition, according to the embodiments, at least one limiting element is provided, which extends from the bottom portion vertically. The limiting element serves as a boundary for the pourable biomass fuel. In some embodiments, the boundary member extends perpendicularly or substantially perpendicularly away from the bottom portion and forms a boundary wall for the bulk biomass fuel. In some embodiments two or more limiting elements are provided. In this case, two limiting elements can be arranged opposite one another on one side of the bottom section. It can also be arranged limiting elements on both sides of the bottom portion.

The combustion trough is set up so that it can occupy at least two operating states. In a first operating state, the bottom section has a first bearing surface for receiving the free-flowing biomass fuel. In a second operating state, the bottom section has a second bearing surface for receiving the free-flowing biomass fuel, wherein the first bearing surface is larger than the second bearing surface and the second bearing surface is at least partially defined by at least one limiting element.

Because the first bearing surface is larger than the second bearing surface, in the first operating state the free-flowing biomass fuel can be distributed over a larger area than in the second operating state. Conversely, this means that in the second operating state, the free-flowing biomass fuel is distributed on a smaller contact surface, resulting in particular in a small amount that then the biomass fuel is more compact together than would be the case on the first, larger contact surface.

The first and the second support surface may be formed on the same side of the bottom portion and / or on opposite sides of the bottom portion.

The first bearing surface is limited in some embodiments substantially of the wall portion.

The second bearing surface is at least partially bounded by the at least one limiting element. The second bearing surface can also be limited by two limiting elements. In some embodiments, e.g. two boundary elements and parts of the wall portion, each extending between the boundary elements, the second support surface.

In the second operating state, consequently, a smaller trough for receiving the free-flowing biomass fuel may be formed, inter alia, by the at least one delimiting element than is the case in the first operating state.

The lower contact surface of the second operating state leads, as indicated above, to a certain amount of filled, pourable biomass fuel typically being more compact, that is to say having a plurality of layers one above the other, than in the first operating state. For small quantities of free-flowing biomass fuel, it may happen, for example, that such an amount could be arranged on the first support surface only in one layer, while it is arranged stacked on the second (smaller) support surface due to the smaller area size. As a result, a higher firing temperature and thus a better combustion behavior and better combustion can be achieved than would be the case with a flat, possibly single-ply distribution of the biomass fuel.

The combustion trough can generally be set to the first or second operating state manually and / or automatically. This may either be provided directly on the firing pit itself or it may be e.g. a corresponding device in an oven in which the combustion trough is provided arranged.

The bottom portion is rotatably supported in some embodiments. As a result, combustion residues can be dumped into an ash box arranged below the bottom section.

However, in some embodiments, rotation of the bottom section, e.g. by 180 °, the combustion trough from the first to the second operating state and vice versa. For example, the first bearing surface may be formed on one side / main surface of the bottom portion and the second bearing surface on the second opposite side / surface of the bottom portion. In the first operating state of the bottom portion is then rotated so that the first bearing surface facing up and the biomass fuel can be placed on it. In order to get into the second operating state, the bottom section, e.g. rotated 180 °, so that the second bearing surface is arranged at the top and the first below. This rotation can be done manually and / or automatically, as stated above.

The at least one limiting element is (only) arranged on one side of the bottom section in some embodiments. For some, no boundary element is arranged on the other side accordingly.

In some embodiments, the at least one limiting element is displaceable and arranged in a first position in the first operating state and in a second position in the second operating state so that it at least partially limits the first bearing surface in the first operating state and the second bearing surface in the second operating state. The shift can be done manually and / or automatically. The limiting element may, for example, be displaceably arranged in the bottom section via a rail guide.

In some embodiments, two limiting elements (or more) are provided on one side of the bottom portion, the distance of which is adjustable relative to each other. In a first relative position with a first distance to one another, the delimiting elements at least partially define the first bearing surface and in a second relative position with a second, smaller distance from each other they at least partially define the second bearing surface. In the first operating state, the limiting elements are arranged in the first position and in the second operating state in the second position.

In general, the bottom section can also be designed as a grate, in particular as a tilting grate. The bottom section may optionally have a series of apertures or holes through which combustion debris is forced downwards by gravity, e.g. fall into an underlying ash pan. In addition, primary air can also be supplied through the perforations from below to the biomass fuel arranged on the bottom section on the first or second support surface.

In some embodiments, the wall portion has at least one opening into which engages the at least one limiting element in one of the two operating states. This makes it possible, for example, for the rotation of the bottom section from the first operating state to the second operating state, for the limiting element or limiting elements, which partially define the second supporting surface, to be pivoted into the trough space formed by the wall section Turn around.

In some embodiments, at least one locking portion is provided, which engages in the other operating state in the at least one opening. As a result, the openings in the wall section are closed in any operating state, so that no biomass fuel can fall through.

Some embodiments relate to a furnace having a combustion chamber and a combustion trough, wherein the combustion trough is arranged in the lower region of the combustion chamber. Upon combustion of the bulk biomass fuel in the combustion trough, the resulting flames may extend into the combustion chamber.

The furnace can be designed as a pellet stove and the firing pit accordingly as a pellet burner. In some embodiments, the furnace is formed together with the combustion trough for the combustion of wood chips.

In some embodiments, the oven is adapted to automatically set the firing tray in the first and in the second operating state. For this purpose, the furnace has an electronic control or regulation and a means for setting the combustion trough in the first or second operating state. The electronic control is set up to set the combustion trough in the first or second operating state as a function of a heating power requirement. The electronic controller may include a microprocessor and a memory for storing a control program and control data. The means for setting the combustion trough into the first and second operating states can be formed, for example, by an electric drive which, for example, as described above, rotates the bottom section and / or displaces the limiting section. In some embodiments, the means for setting the combustion bowl in the first and second operating states comprises a hydraulic drive or a combination thereof or a different kind of mechanical drive.

The oven may include an input device in which a user inputs whether he wants a high or a low heating power requirement. Depending on whether more or less biomass fuel is needed and set the combustion trough in the first operating state (higher heat output) or second operating state (lower heat output) and filled according to biomass fuel.

As mentioned above, in some furnaces setting the combustion trough in the first and second operating state can also be done manually. For this purpose, for example, a lever, a slider or a crank is provided to rotate the bottom portion as above or to move the boundary element (s).

Coming back to the Fig. 1 to 3 These embodiments illustrate a pellet burner 1 in accordance with the present invention in three different states.

Fig. 1 illustrates the pellet burner 1 in a first operating state with a first pellet bearing surface 5a. The Fig. 2 illustrates the pellet burner 1 in a transition from the first to a second operating state, which in Fig. 3 is illustrated and in which the pellet burner has a second pellet bearing surface 5b, wherein the second Palletauflagefläche 5b is smaller than the first Pelleltauflagefläche 5a in the first operating state.

The pellet burner 1 is adapted for the combustion of pellets and may e.g. be used in a pellet stove.

The pellet burner 1 has an outer wall section 3, which extends annularly around a bottom section 2. The bottom portion 2 and the outer wall portion 3 together form a trough in which pellets can be taken up and burned, the bottom portion 2 forming the bottom of this trough.

In this embodiment, the bottom portion 2 is formed as a dip with holes 9 through which primary air can be supplied for combustion and can fall through the combustion residues down. The holes 9 are designed so that pellets do not fit through and therefore can not fall through, but remain on the bottom portion 2 and the support surface 5a and 5b of the bottom portion 2. However, embodiments are also provided without holes in the bottom section.

The bottom section 2 is rotatably supported by a shaft 8 which extends into a corresponding bearing in the wall section 3. Alternatively, the shaft can also be integrated in the bottom section.

In the in Fig. 1 shown first operating state of the pellet burner 1, a first larger bearing surface 5a is formed on the bottom portion 2. The boundary of the larger support surface 5a is formed essentially by the outer wall section 3 and the bottom section 2, so that the support surface 5a the entire top of the bottom section 2 occupies.

The bottom portion 2 can be rotated by 180 °, as in Fig. 2 indicated, so im in Fig. 3 illustrated second operating state, the second smaller bearing surface 5b is at the top.

The second smaller bearing surface 5b is delimited by two opposite regions of the outer wall section 3, which each extend between two opposing boundary elements 4a and 4b.

The two boundary elements 4a and 4b extending opposite each other extend vertically upward from the bottom section 2 in the second operating state and form two boundary walls. The boundary elements 4a and 4b are disposed within the outer wall portion 3 and thereby reduce the trough volume. Together with the opposite regions of the outer wall section and the small bearing surface 5b of the bottom section 2, they form a smaller recess for receiving pellets than is the case in the first operating state.

In order to enable the rotation of the bottom portion 2 with the boundary members 4a and 4b disposed thereon, the outer wall portion 3 has respective openings 6a to 6d formed in a slot shape in the outer wall portion 3 at the positions where the restriction members 4a and 4b engage.

In the second operating state, in which the small bearing surface 5b is arranged at the top, so that the pellets can be arranged on it for combustion, the limiting elements 4a and 4b thus engage in the apertures 6a to 6d essentially with their outer edge regions. The openings 6a to 6d are slightly thicker than the wall thickness of the limiting elements 4a and 4b. They are dimensioned so that no pellets can fall through the gap, which forms when the limiting elements 4a and 4b engage in the openings 6a to 6d.

Since in the first operating state, the bottom portion 2 is rotated by 180 ° with respect to the second operating state and consequently the limiting elements 4a and 4b point downwards in the first operating state and do not engage in the apertures 6a to 6d (see FIG Fig. 1 ), are opposite to the limiting elements 4a and 4b rod-shaped locking portions 7a to 7d provided that extend from the bottom portion 2 so that they engage in the first operating state in the openings 6a to 6d and close this, so that no pellets through the openings 6a to 6d can fall through. The locking portions 7a to 7d are formed in their cross-section so that they substantially close the apertures 6a to 6d and quasi steadily continue the outer wall portion 3 and do not protrude into the interior of the trough.

The locking portions 7a to 7d are arranged in pairs opposite one another and are located on the opposite side of the bottom portion 2 with respect to the limiting elements 4a and 4b at the same positions on which the limiting elements 4a and 4b are arranged. They therefore limit in the first operating state as parts of the outer wall portion 3 and the first larger bearing surface 5a.

The limiting elements 4a and 4b as well as the blocking sections 7a to 7d are essentially integrally formed on the bottom section 2 in the present embodiment. In other embodiments, the limiting members 4a and 4b and / or the locking portions 7a to 7d may also be otherwise secured to the bottom portion 2 (e.g., bolted, riveted, inserted, inserted, or the like).

Claims (10)

Firing well for pourable biomass fuel, comprising: a bottom section (2) for receiving the bulk biomass fuel; a wall portion (3) extending at least partially around the bottom portion (2); and at least one restriction member (4a, 4b) extending vertically from the bottom portion (2); wherein the combustion trough (1) is arranged such that it can assume at least two operating states: a first operating state, in which the bottom section (2) has a first support surface (5a) for receiving the free-flowing biomass fuel, and a second operating state in which the bottom section (2) has a second bearing surface (5b) for receiving the free-flowing biomass fuel, the first bearing surface (5a) being larger than the second bearing surface (5b) and the second bearing surface (5b) at least partially passing through the at least one limiting element (4a, 4b) is limited. Firing trough according to claim 1, wherein the bottom portion (2) is rotatably mounted. Firing trough according to one of the preceding claims, in which the at least one delimiting element (4a, 4b) is displaceable and is arranged in a first position in the first operating state and in a second position in the second operating state. Firing trough according to one of the preceding claims, in which the bottom section (2) is designed as a combustion grate, in particular as a tilting grate. Firing trough according to one of the preceding claims, in which the wall section (3) has at least one opening (6a-6d) into which the at least one delimiting element (4a, 4b) engages in one of the two operating states. Firing trough according to claim 5, further comprising at least one locking portion (7a-7d) which engages in the at least one opening (6a-6d) in the other operating condition. Firing trough according to one of the preceding claims, which has at least two delimiting elements on one side of the bottom section, which are displaceable relative to one another. Oven having a combustion chamber and a combustion trough (1) according to one of the preceding claims, wherein the combustion trough (1) is arranged in the lower region of the combustion chamber. Furnace according to claim 8, which is designed as a pellet stove and wherein the combustion trough is formed as a pellet burner trough. Oven according to one of claims 8 or 9, further comprising an electronic control and means for setting the firing trough (1) in the first or second operating state, wherein the electronic control is adapted to the firing trough (1) in dependence on a heating power requirement to set in the first and second operating state.

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