EP0057904B1 - Stove for space heating - Google Patents

Abstract

1. A stove for heating a room, in particular a tiled stove, which is built up from a plurality of superposed annular stove elements (E) having a preferably rectangular or square external plan and which comprise a heat-retaining layer (2) of refractory concrete which is poured into a continuous frame (1; 34; 42) of strong heat-resistant material which forms the outer surface of the stove, the height of the frame (1; 34; 42) being equal to the height of the stove element (E), characterized in that the concrete layer (2) is free of a lining on its inner surface (2a) and comprises a plurality of grooves (20) starting from the inner surface (2a) and arranged outside corner areas and the walls (3a to 3d; 42a, 42b) of the continuous frame (1; 34; 42) comprise single-piece plates.

Description

The invention relates to a stove for space heating, in particular to a tiled stove, which is constructed from a plurality of stacked ring-shaped stove elements, preferably of a rectangular or square outline, which have a heat-storing layer of refractory concrete, which forms the outer surface of the stove coherent frame is cast from solid heat-resistant material, the height of the frame being equal to the height of the furnace element.

Such an oven is known from DE-C-471 753.

Furnaces of this type have a large heat storage capacity due to the concrete mass. Such stoves are often designed as tiled stoves. However, the outer cladding does not have to be in the form of tiles. It is only important that the outer cladding is sufficiently heat-resistant and has the required mechanical strength. The advantage of heat-storing stoves is that the room heating is very even, even if the intensity of the fire in the stove fluctuates. A heat-storing stove is also largely an all-rounder and allows, for example, the burning of wood waste.

A furnace that is stacked from individual furnace elements has the advantage that it can be industrially prepared to such an extent that it can be assembled from the individual furnace elements at the installation site within a short time. Despite the inherently very high weight of such a furnace, the individual furnace elements can be handled relatively easily, so that the buyer can easily build them themselves.

The thermal stresses in the concrete are problematic with furnaces made of concrete rings, which occur mainly because there is a strong heat gradient in the concrete from the inside to the outside. In order to avoid cracking of the concrete rings, in a known construction (DE-C-360 244) the concrete rings were divided by inserted metal sheets and the tile-like parts formed in this way were held together by iron inserts. However, such a construction does not have the desired tightness. The outer surface of the furnace is also unsatisfactory because it is made of concrete.

In the known oven of the type mentioned (DE-C-471 753), the concrete layer is cast between said frame and an inner frame. The concrete layer is relatively thin and is mainly used to firmly connect the inner frame to the outer frame. No means are described in the cited publication with which the formation of cracks on the inner frame and the concrete layer is to be avoided. The construction of the furnace elements from three layers requires a lot of material and labor.

The invention has for its object to design a furnace of the type mentioned in such a way that a large heat storage capacity can be achieved at low cost and breakage of parts of the concrete layer due to shrinkage stresses and / or thermal stresses is avoided.

This object is achieved according to the invention in that the concrete layer on its inner surface is free of cladding and has a plurality of grooves starting from the inner surface and arranged outside corner areas and the walls of the connected frame consist of one-piece plates.

By omitting a cladding within the concrete layer, a substantial saving in material and manufacturing costs is achieved. A large heat storage capacity can nevertheless be achieved, since the concrete layer can also be made very thick by the arrangement according to the invention, without the risk that leaks occur when the furnace is used. If stresses occur in the concrete layer, stress cracks may form at the points where the grooves are present, the cracks starting from the groove base. The stress cracks can reach up to the frame. Such cracks do not lead to the breaking out of concrete pieces, since cracks in the concrete never lead to smooth fracture surfaces. The rough fracture surfaces interlock positively so that cohesion is maintained, which prevents individual pieces from falling out. Despite the fact that numerous continuous cracks are permitted, the escape of smoke gases is avoided by the fact that the walls of the frame consist of contiguous plates and by the grooves being arranged outside corner areas. In a furnace designed in this way, the cracks emanating from the grooves can pass through to the frame without any leakage points through which the flue gases could escape. The cracks are sealed by means of the continuous plates. In the corner areas of the frame, where the joints of the panels are and where the frame is therefore permeable, a secure seal is achieved through the concrete. By allowing cracks outside the corner areas, you can be sure that the corner areas remain free of cracks. The invention has made it possible to produce stoves with a very large heat storage capacity industrially using a simple and rational process. Compared to the conventional manufacturing method for tiled stoves, the manufacturing is made considerably cheaper, so that stoves with a high heat storage capacity can also be installed where this was not possible due to the high installation costs of tiled stoves of conventional design due to cost reasons. This is particularly interesting in terms of the possibility of using space heating instead of heating to use oil-resistant fuels, especially wood.

The toothing in a crack area is particularly good if a coarse-grained refractory concrete is used according to claim 3. Since the grains do not break through in stress cracks, particularly effective gearing is achieved with coarse-grained concrete at crack locations.

Particularly expedient dimensioning of the groove depth and a particularly expedient groove arrangement are specified in claims 2 and 4.

Protrusions on the inside of the frame (claim 5) help to hold the concrete parts remaining after the formation of cracks on the element.

• . Fig. 1 eine perspektivische Ansicht eines Ofenelementes,
• Fig. 2 einen Querschnitt durch ein Ofenelement entsprechend der Linie 11-11 in Fig. 1, wobei auch eine Tragvorrichtung gezeigt ist,
• Fig. 3 einen der Fig. 2 entsprechenden Querschnitt bei einem obersten Ofenelement mit Abdeckung,
• Fig. 4 einen entsprechenden Querschnitt bei einem Ofenelement mit Tür- und Reinigungsöffnung,
• Fig. 5 eine perspektivische Darstellung einer Rahmen-Eckverbindung mit Krampen,
• Fig. 6 einen Horizontalschnitt durch einen Rahmen eines Ofenelementes, bei dem die Rahmenteile durch angeschraubte Verbindungsstücke miteinander verbunden sind und
• Fig. 7 einen Horizontalschnitt durch einen Rahmen, bei dem die Rahmenteile durch Ineinandergreifen entsprechend profilierter Ränder der Rahmenteile miteinander verbunden sind.

Exemplary embodiments of the invention are shown in the drawing. Show it:

• . 1 is a perspective view of a furnace element,
• 2 shows a cross section through a furnace element along the line 11-11 in FIG. 1, a carrying device also being shown,
• 3 shows a cross section corresponding to FIG. 2 for an uppermost furnace element with a cover,
• 4 shows a corresponding cross section in a furnace element with a door and cleaning opening,
• 5 is a perspective view of a frame corner connection with cramps,
• Fig. 6 is a horizontal section through a frame of a furnace element, in which the frame parts are connected to each other by screwed connectors and
• Fig. 7 is a horizontal section through a frame in which the frame parts are interconnected by interlocking correspondingly profiled edges of the frame parts.

A complete furnace is not shown in the drawing. A complete furnace is formed by stacking several furnace elements E, as shown in Fig. 1. Depending on the desired heating output of the furnace, more or fewer elements can be used. A relatively small furnace could, for example, be formed from four elements, while a relatively large furnace, e.g. B. consists of six elements. Fig. 1 shows the simplest version of a furnace element in which openings are not available. Fig. 4 shows a cross section through an element with a door and cleaning opening.

1 has a square outer shape. It consists of a frame, generally designated 1, into which a ring, generally designated 2, is cast from concrete. The nature of these main components is explained in detail below.

The frame 1 consists of four identical frame parts 3a to 3d. These parts consist of cast iron and have such a surface profile that there is an imitation of three tiles 4, 5 and 6 on each part. As the cross-section according to FIG. 2 in particular makes clear, the tile fields have edges 7 which delimit a depression 8. There are shadow gaps 9 between the tiles. At their upper and lower edges, the elements 3a to 3d are provided with an inward edge 10 and 11, respectively. Cams 12 rise from the inside of the frame parts.

The height h of the frame 1 and the concrete ring 2 are exactly the same. This also results from the production, in which the frame is placed on a molding plate and filled with concrete up to its upper edge.

The frame parts 3a to 3d meet at the corners of the element E and are connected to one another there according to FIG. 5. For the purpose of connection, projections 13 to 16 are formed on the frame parts. There is a hole 17 in each projection. A first U-shaped clamp 18 is inserted through the holes 17 of the projections 13, 14 and a second clamp 19 is passed through the holes in the projections 15, 16. On the finished element, the protrusions and the cramps are embedded in the concrete, creating an additional positive connection between the concrete and the frame.

For clarification, it is noted that the frame parts 3c and 3d are only shown schematically in FIG. 5, that is to say they do not show the profiling that is shown in FIGS. 1 and 2.

The concrete ring 2 has a large wall thickness s in order to form a large heat-storing mass. The concrete ring 2 is produced in that the frame 1, after its parts have been put together by means of the cramps 18, 19, is placed on a lower mold part on which a core is located. Thereafter, the space between the core and the frame 1 is filled with flowable or at least stampable refractory concrete. In this process, the described corner connections are enclosed by the concrete. Likewise, the cams 12 are embedded in the concrete.

When the concrete ring 2 is formed, a plurality of grooves 20 are also formed in the concrete, which start from the inner surface 2a of the concrete ring and extend over a large part of the thickness s of the concrete ring 2. For example, the depth t of the grooves 20 can be so great that they extend over three quarters of the thickness s of the concrete ring. Shown is a groove arrangement which is such that there are three grooves on each side, which are aligned with the shadow gaps 9 of the frame.

On the inside 2a of the concrete ring 2 there are also depressions 21 for the engagement of a support device designated overall by T. This support device has a support rod 22, on which support hooks 23 are slidably and fixably fastened. The support hooks 23 have horizontal legs 23a which engage in the depressions 21. By locking the support hook on the rod 22 by means of screws 24, any risk of the hook slipping out of the recesses 21 is excluded.

The top furnace element E ', which in Fig. 3 in Cross section is shown in principle has the same structure as the element already described. It differs from this in that a groove 25 with a V-shaped cross-section is located on the upper side of the concrete ring designated 2 ′ here. This groove serves to fix an upper cover plate, designated overall by 26, which consists of metal, preferably of cast iron. The cover plate 26 has a strip-like edge 26a which projects downwards and engages in the groove 25. The plate can be sealed against the interior 27 of the furnace by inserting sealing material into the groove 25. Two options are shown for this. According to the alternative shown on the left, the groove 25 contains a filling 28 made of granular loose material, for. B. of sand or salt. According to the alternative shown on the right in FIG. 3, a coherent seal 29, for example an asbestos cord, is inserted into the groove 25. It is essential that the seals must not hinder the lifting off of the plate 26, so that, as explained at the beginning, in the event of deflagration, the pressurized gases can lift off the plate and thus escape.

The basic structure of the element E "shown in FIG. 4 is also the same as that of the elements E and E '. The arrangement of two openings 30 and 31 is different from these elements. The opening 30 can be, for example, a combustion opening through a Cast iron door 32 is closed, opening 31 can be a cleaning opening which can be closed with a cover 33.

6 and 7 show further construction options for frames of furnace elements. The frame 34 according to FIG. 6 is also assembled from four parts. Connection parts 35, which are screwed to adjacent parts of the frame, are used for the connection. The screw connection is only symbolically indicated by dash-dotted lines 36. The connecting parts 35 have a region 35a which is at a distance from the rear of the frame parts. Concrete can again flow into the intermediate space 37. It can e.g. B. two relatively narrow connecting parts 35 are arranged at each corner one above the other at a distance from one another, so that the connecting parts are completely encased in concrete.

The frame 42 according to FIG. 7 is composed of four parts which are shaped identically in pairs. The parts 42a have a U-shaped profile with end legs 43 on their vertical edges. The frame parts 42b also have a U-shaped edge profile, but the groove formed by this profile is turned with its opening outwards, while the groove 45 of the edge profile the parts 42a faces inwards.

The connection of the frame parts to one another does not require any special connecting pieces, since a clawing is achieved by the edge profiling. The concrete mass prevents the parts 42b from being able to move inwards.

Claims (5)

1. A stove for heating a room, in particular a tiled stove, which is built up from a plurality of superposed annular stove elements (E) having a preferably rectangular or square external plan and which comprise a heat-retaining layer (2) of refractory concrete which is poured into a continuous frame (1, 34; 42) of strong heat-resistant material which forms the outer surface of the stove, the height of the frame (1, 34; 42) being equal to the height of the stove element (E), characterized in that the concrete layer (2) is free of a lining on its inner surface (2a) and comprises a plurality of grooves (20) starting from the inner surface (2a) and arranged outside corner areas and the walls (3a to 3d; 42a, 42b) of the continuous frame (1; 34; 42) comprise single-piece plates.

2. A stove according to Claim 1, characterized in that the grooves (20) extend at least over half the thickness (s) of the concrete layer (2), preferably over approximately % of the said thickness (s).

3. A stove according to any one of the preceding Claims, characterized in that the concrete layer (2) consists of a coarse-grained refractory concrete.

4. A stove according to any one of the preceding Claims, characterized in that in the case of a stove with a square cross-section three uniformly distributed grooves (20), which are orientated with false joints (9) on the frame (1), start from each inner surface of the concrete layer (2).

5. A stove according to any one of the preceding Claims, characterized in that projections (12) in the form of pins or strips are integrally formed on the inside of the frame (1; 34; 42).

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