FI71481C - Sauna oven. - Google Patents

Description

1 71481

Saunankiuas - Bastu-ugn

The invention relates to a sauna heater which is heated by solid fuel and comprises a grate-equipped firebox, an associated flue, a stone space and a space formed between the firebox and the flue, bounded by a closed plate adjoining the stone space through which the flue is led to the stone space and a flue gas baffle adjoining the furnace, substantially in shape corresponding to the cross-sectional shape of the furnace, the furnace and the flue communicating via said space through an opening in the edge region of the baffle to the edge region of the baffle plate.

Such a sauna heater is known from FI patent 28254 and it is an object of the present invention to provide an improvement in the heat transfer of a sauna heater belonging to the prior art. Heat transfer in this context means the transfer of the heat contained in the gases generated in a firebox firing event from the firebox and chimney to the stones in the rock space. The sauna-heater structure according to the invention provides efficient flue gas recirculation and thus a longer heat transfer distance as the flue gases move from the furnace to the flue.

To achieve these objects, the sauna heater according to the invention is mainly characterized in that flow guides are formed in the edge area of the baffle plate in order to provide a tangential and helical flue gas flow in the direction of the baffle plate.

71481 In this way, efficient heat transfer is achieved between the flue gases generated in the furnace and the stone space, since the flue gases have to travel a long distance before the part of the flue outside the stone space. In this case, the heat transfer to the stones becomes efficient.

Further development forms of the sauna heater according to the invention are set out in the appended claims.

The invention is further illustrated in the following description, in which reference is made to an exemplary embodiment shown in the accompanying drawings. In the drawings, Fig. 1 shows a vertical section of a heater according to the invention and Figs. 2 and 3 show sections A-A and B-B of Fig. 1 and Fig. 4 shows a perspective view of the connection of the flue and the guide plate in the state according to the invention.

Referring to Figures 1-3, the stove according to the invention comprises a furnace 1, the lower part of which has a grate 2 for burning solid fuel. Fuel, e.g. wood, is introduced into the furnace through hatch 3. To remove the ash, an ash box 4 is placed below the grate. A refractory metal can be used as the material of the firebox, and the firebox is preferably circular in cross-section. Outside the firebox there is a protective cladding 5 arranged concentrically with the vertical central axis of the firebox, the protective cladding 5 also having a circular cross-sectional shape, leaving an annular space 6 between the wall of the firebox 1 and the wall of the protective cladding 5. the air coming through the openings can flow into the stone space 8 through a perforation arranged at the lower edge of the stone space (Fig. 2). This circulation, although not actually part of the invention, enhances the heating of the sauna and the intermediate space 6 as well as the stone space 8 can be advantageously utilized by placing an electric heater in both or both spaces, so that the heater can be used both as a solid fuel heater and as an electrically heated heater. The perforation 8 can advantageously be realized by means of a metal rod 27 bent into a circular shape, which prevents the stones from entering the intermediate space 6 but allows air to circulate between the stones. Such a metal bar, which is bent into a continuous U-shape, can be supported on the lower part of the stone space 8 in several different ways.

Furthermore, the sauna heater comprises a space 9 below the stone space 8 in the upper part of the heater according to the invention, in which the chimney inlet opening 11 is located. The flue 10 is preferably circular in cross-section and arranged concentrically with the central axes of the firebox 1 and the protective cladding 5 above the firebox 1. The space 9 is bounded towards the stone space 8 by a closed plate 12 made of refractory metal, through which the flue 10 is led into the stone space 8. The space 9 is bounded laterally by a firebox extension 13 fixed to the edges of the substantially horizontal plate 12. The space 9 facing the firebox 1 is limited by a substantially planar flue gas baffle 14 supported in the furnace, perpendicular to the central axis of the furnace, directing the flue gas flow first in the furnace 1 to the edges of the baffle plate and second in the space 9 towards the center of the space 9. Furnace 1 and space 9 are in flue gas flow communication. According to the invention, this flow connection can be implemented in several different ways.

4,71481

Figure 4 shows a preferred way of implementing the solution according to the invention. In Fig. 4, the plates 12 and 13 delimiting the space 9 are omitted, as well as the protective cladding of the furnace and the stone space. The figure thus shows the mutual position of the flue 10 and the baffle plate in the space 9. According to the figure, the central axis of the flue 10 is arranged concentrically in the direction of the longitudinal axis of the flue 10 as seen from the center of the circular baffle plate. The orientation plate 14 corresponds in shape and size to the cross-sectional shape of the furnace, and the flow path from the furnace 1 to the space 9 is arranged through openings 29 formed in the edge area of the orientation plate 14. The embodiment shown in Figure 4 causes the flue gases flowing into the space 9 from the edges of the baffle plate 14 to be directed as a tangential and helical flow towards the center of the baffle plate where they meet the flue 10 inlet 11.

In order to provide openings 29 and flow guides at the edges of the baffle plate 4, a plurality of radial cuts 16 are formed in the substantially planar refractory metal baffle 14, forming for example twelve sector portions 17 delimited by two adjacent cuts 16. 17 is bent in the circumferential direction of the baffle plate as seen from the same edge so that the bent part 18 is directed obliquely towards the furnace 1. The part 17 of the baffle plate acting as a flow guide then comprises a part 19 in the main plane of the baffle plate 14 and a bent part 18. The bending line 20 is started from the end point of the section 16 and the bending line forms an angle with the section 16. In this case, the bent parts are mainly triangular in shape. The bending line 20 meets the outer circumference 21 of the orientation plate 14, whereby the total diameter of the orientation plate 14 remains substantially the same even after bending. The openings 29 are formed between the section 18 bent at the cuts 16 and the section 19 in the main plane.

71481

Further formed at the flue opening 11 are flow guides 15 which are an axial extension of the flue inlet 11 and project from an axial extension of the outer surface of the flue 10. They form an angle with respect to the outer surface. The guides are formed by machining the flue so that the flow guide 15 associated with the longitudinal support plane 22 of the flue is bent outwards from the support part 22. The guide part 15 is rectangular or square in shape, cut off at sections 23 and 24 from the end of the chimney and bent outwards along a bending line 28 in the direction of the central axis of the chimney.

The structure according to Figure 4 provides the flue gas flow shown by arrow 25. The flue gases first come from the furnace 1 as a tangential flow substantially parallel to the baffle plate 14 and in a helical shape in space 9 towards the center of the baffle plate, where they meet guides 15 arranged at the lower edge of the flue inlet. as a flow.

The baffle plate 14 can also be implemented in a shape substantially corresponding to the cross-section of the furnace, but smaller, whereby a flow path is formed between the outer edge of the baffle plate and the furnace. Flow guides, for example vanes corresponding to the parts 18, attached to the firebox can be placed in this flow path. Furthermore, the flow guides 15 can be manufactured as a separate piece which is mounted at the end of the flue.

Claims (7)

71481 A sauna heater which is heated by solid fuel and comprises a furnace (1) with a grate (2), an associated flue (10), a stone space (8) and a space (9) formed between the furnace (1) and the flue (10), bounded by a closed plate (12) bordering the stone space (8), through which the flue (10) is led by a flue gas baffle plate (14) bordering the stone space (8) and the firebox (1), substantially corresponding to the cross-section of the firebox (1); 1) and the flue (10) in flow communication via said space (9) through an opening in the edge region of the baffle plate (14) to the edge region of the baffle plate (14), characterized in that flow guides (17) are formed in the edge region of the baffle plate (14), to provide a tangential and helical flue gas flow in the direction of the baffle plate (14). Sauna heater according to Claim 1, characterized in that guides (15) are formed at the inlet opening (11) of the flue (10), which project as an axial extension of the inlet opening (11) of the flue (10) from the outer surface of the flue and form an angle (10) with respect to the outer surface for introducing a flue gas flow into the flue (10). Sauna heater according to Claim 1, characterized in that radial cuts (16) are formed at regular intervals in the guide plate (14) in order to provide flow guides (17) and that a part of the guide plate part (17) between the two cuts is bent obliquely into the firebox. (1), whereby an opening (29) is formed at each section (16) and the flow guide (17) comprises a part (19) in the main plane of the baffle plate and a bent part (18). Il 7 71481 Sauna heater according to claim 3, characterized in that the bending line (20) is started from the end point of the cut (16) and that the bending line forms an acute angle with the cut (16) ending at the outer circumference (21) of the orientation plate. Sauna heater according to Claims 3 and 4, characterized in that the orientation plate (14) corresponds in size to the cross-sectional shape of the firebox (1) and is arranged perpendicular to the central axis of the firebox (1) of circular cross-section. Sauna heater according to Claim 2, characterized in that the guides (15) arranged at the inlet of the flue (10) are produced as a separate piece which is connected to the end of the flue (10). Sauna heater according to Claim 2, characterized in that the guides (15) formed at the inlet opening (11) of the chimney (10) are machined from the end part of the chimney in such a way that each of the longitudinal and outer surface support parts (22) the flow guide (15) is bent outwards from the support part (22) along a bending line (28) parallel to the central axis of the flue, the guide part (15) being detached by a cut (23, 24) from the end of the flue (10) a corresponding opening (25) of the guide part (15) is connected to the inlet opening of the flue (10). 71481 Patentkrav;