ELECTRICALLY HEATED SAUNA OVEN

Abstract: The invention relates to an electrically heated sauna oven comprising a housing (1), a number of stone elements (2), particularly soap rock elements, and electric resistor elements (3); the power fed into the electric resistor elements is controlled by means of a control unit (4). According to the invention, the stone elements (3) are slabs which are attached adjacently in the housing (1), and the electric resistor elements are fitted inside each stone element (2).

Description: ELECTRICALLY HEATED SAUNA OVEN The present invention relates to an electrically heated sauna oven which conforms to the introductory section of the independent patent claim. in the prior art there are known several electric sauna ovens where electric resistor elements are installed inside a box-like housing, and sauna oven stones are arranged In connection with the resistors. The electric resistor elements are heated by means of electric current, and they in turn heat the oven stones proper. When the temperature in the sauna has reached the preset limit, the control unit switches off the current supply to the resistor elements, and after the temperature has declined below a given limit, the control unit reswitches the resistor elements to the network. Among the drawbacks of the known electrically heated sauna ovens, let us point out the following. The sauna oven reguires a determined space both as for the width and the depth. It is difficult to fit a sauna oven in the fairly closed guarters of today. Furthermore, the maintenance of an electrically heated sauna oven may bring about problems. When an electric resistor element is damaged, the oven stones must be dismounted from the top of the elements as well as from between them before the resistors can be reached. The object of the present invention is to introduce a new type of electrically heated sauna oven whereby the above mentioned drawbacks, among others, can be avoided. In order to achieve this, the electrically heated sauna oven of the invention is characterized by the novel features described in the first patent claim. The electrically heated sauna oven of the present invention needs little maintenance and is depthwise fitted in a small space. The stone elements, particularly soap rock elements, can be easily replaced when necessary. Generally speaking, the electrically heated sauna oven of the present invention requires extremely little care, is simple in structure and easy to install. Moreover, various sizes of sauna ovens can be constructed by employing different numbers of similar stone elements. The invention is below explained in more detail with reference to the appended drawings, where figure 1 is a front-view illustration of an electrically heated sauna oven of the invention; figure 2 is an illustration of the sauna oven of figure 1, seen along the cross-section A-A; figure 3 shows the stone element from below; figure 4 is an illustration of the element of figure 3, seen along the cross-section B-B; figure 5 is a front-view Illustration of a sauna oven of the invention, which oven is built in the wall of the sauna; and figure 6 shows the sauna oven of figure 5, seen along the cross-section C-C. The electrically heated sauna oven of the invention of figures 1 and 2 comprises a housing 1, a number of stone elements 2, particularly soap rock elements, and a number of electric resistor elements 3, which are arranged in connection to the stone elements, and whereto electric power is supplied by means of the control unit 4. The stone elements 2 are slabs which are adjacently fastened to the housing 1. The electric resistor elements 3 are fitted inside each stone element 2. The electric resistor elements 3, six altogether in the described embodiments, are switchted in pairs coupled in series and connected through the control unit 4 to each phase of a three-phase net. The control unit 4 can be any type of previously known control unit which is used in connection with electrically heated sauna ovens and whereby the resistor elements 3 are connected to the electric network, controlled by means of for instance a thermostat. The housing 1 is formed of a plate-like underlay. In figures 1 and 2, the housing is installed in a vertical position in the sauna wall 8. The housing 1 is provided with fastening supports 9, whereby the fastening to the wall 8 is carried out. If necessary, the housing 1 can also be provided with auxiliary legs 10, which support the sauna oven against the floor 11. The stone elements 2 are advantageously slabs with a similar form, in this case a regular quadrangle. Thus the stone elements are mutually replaceable, and by using these similar stone elements, various sizes of electrically heated sauna ovens can be compiled by changing the number of the elements. The front surface 2a of the stone elements 2 is advantageously roughed or otherwise made uneven, for instance provided with recesses 12. The purpose of the roughening or other unevenness is to improve the evaporation capacity of the elements - i.e. the rougher the surface, the less water flows down the vertical or inclined surface. The stone elements 2 are fastened to the housing 1 preferably in a removable fashion. Thus any stone elements that are for one reason or another damaged during use, can be replaced with new equivalent elements. Each stone element can be provided with fastening screws 7 or with other fastening members, whereby they are fastened to the housing 1. In the electrically heated sauna oven of the invention, the said stone elements 2 are advantageously soap rock elements. Soap rock is a greyish alteration product of a rock type containing just a little of silicon acid and is mainly composed of talcum and magnesite or dolomite. It is easily workable stone material which endures acids and alkalis relatively well and is fairly resistant to changes in the temperature. In addition to this, soap rock is famous for its excellent heat capacity. Still, it is maintained that other rock types can also be used in the stone elements. However, very large stone elements 2 cannot be used in the electrically heated sauna oven of the invention, if the material Is soap rock. It has been observed that an advantageous size for a square stone slab is 300 x 300 mm and thickness 30 mm. For instance a 1 kW wire resistor element is easily installed inside such a stone element. If soap rock elements larger in measure are used, they should be supported at the sides for instance by means of compression straps in order to prevent the slabs from breaking by sharp changes in the temperature. When the aforementioned size is used, there is no need for any extra supports for the stone elements. Figures 3 and 4 illustrate how the electric resistor element is fitted inside the stone element 2, which is advantageously a soap rock element. The electric resistor element 3, which is advantageously in the form of wire, is fitted in the groove 5 arranged on the back surface 2b of the stone element 2, and the groove 5 is at least partly filled with mortar 6, preferably fire-resistant mortar. The groove which is arranged on the back surface 2b of the stone element 2 is relatively narrow and deep in shape. The depth s of the groove 5 is for instance half of the thickness b of the stone element 2, and the width k of the groove is a third of the depth s thereof. It is obvious that these values are only advisory and that remarkable deviations from them are possible without any essential changes in the operation of the stone element. The groove 5 is arranged to circulate the back surface 2b of the stone element in two parallel grooves 5a, 5b, at a distance a from each other and united to each other. Advantageously the distance a is constant, but variations are also possible. The purpose is to make the groove 5 and the electric resistor element 3 fitted therein to cover the surface of the stone element 2 as evenly as possible, so that the heat delivered by the resistor element would also spread evenly over the whole stone element. Figures 5 and 6 illustrate a sauna oven of the invention, which oven is built in the wall of the sauna. In the sauna wall 13, there is arranged a recess 14. The fitting frame 15 is fitted in the recess 14 and attached in place. The housing 1 of the sauna oven together with the stone elements 2 is fastened to the fitting frame 15, which may be provided with suitable brackets or other fastening members. The purpose of the fitting frame 15 is to seal and insulate the recess 14 in the sauna wall so that moisture from the air inside the sauna cannot enter the structures of the wall 13. Advantageously the fitting frame 15 is a basin-like member, which can be fitted in the sauna wall, advantageously to the recess 14 provided in the wall. At least partly inside the fitting frame 15, there are arranged the housing 1 and stone elements 2 of the sauna oven. The stone elements may even be located on the same level as the surface of the wall 13, as is illustrated in figure 6. The fitting frame 15 can also be realized so that the housing 1 of the sauna oven, which is composed of a plate-like member, is directly formed to serve as the fitting frame. In that case there is no need for a separate fitting frame 15, but the housing 1 is employed as the fitting frame. The electrically heated sauna oven of the invention can be provided with bars 16 or the like extending from side to side, as is illustrated in figure 5. Alternatively, the bars can be arranged to extend in a parallel fashion from top to bottom. These bars serve as safety protection when bathing in the sauna. They prevent the bathers from accidentally falling against the hot stone elements 2. In the above specification, the housing 1 of the sauna oven of the invention is realized as a plate¬ like underlay. The housing 1 can also be realized for instance by means of a partly vertically installed plate-like underlay or by means of an underlay which can at least partly be installed at a sharp angle, i.e. with an angle of inclination which gradually changes when proceeding downwards. On the other hand, it is even possible that the housing is set in an at least partly horizontal position, or that the stone elements fastened thereto are at a deviant angle with respect to the underlay. In the above description the invention is explained mainly with reference to one preferred embodiment only, but it is naturally clear that the invention can be modified in many ways within the scope of the inventional idea defined in the appended patent claims.

Claims: PATENT CLAIMS 1. An electrically heated sauna oven comprising a housing (1), a number of stone elements (2), particularly soap rock elements, and electric resistor elements (3), which are arranged in connection to the stone elements (2), c h a r a c t e r i z e d in that the housing is formed of a plate-like underlay, which is positioned mainly vertically or at least inclined at a sharp angle, and that the stone elements (2) are slabs which are adjacently attached to the housing (1) and that the electric resistor elements (3) are fitted inside each stone element (2). 2. The sauna oven of claim 1, c h a r a c - t e r i z e d in that the stone elements (2) are mutually alike slabs of a regular shape. 3. The sauna oven of claim 1 or 2, c h a r a c t e r i z e d in that the front surface (2a) of the stone elements (2) is roughed or otherwise made uneven, for instance provided with recesses ( 5 ) • 4. The sauna oven of claim 1, 2 or 3, c h a r a c t e r i z e d in that the stone elements (2) are removably attached to the housing (1). 5. The sauna oven of any of the preceding claims, c h a r a c t e r i z e d in that the sauna oven includes a fitting frame (15) which can be attached to the sauna wall (13), and in which frame the housing (1) of the sauna oven can be fitted. 6. The sauna oven of claim 5, c h a r a c - t e r i z e d in that the fitting frame (15) is a basin-like member which can be built in the sauna wall (13) and inside which member the housing (1) of the sauna oven and the stone elements (2) can be at least partly installed. 7, The sauna oven of claims 5 or 6, c h a ¬ r a c t e r i z e d in that the housing (1) of the sauna oven is formed to serve as the fitting frame (15). 8. The sauna oven of any of the preceding claims, c h a r a c t e r i z e d in that the electric resistor element (3) is fitted in a groove (5) arranged on the back surface (2b) of the stone element (2), and that the groove (5) is at least partly filled with some preferably heat-resistant mortar (6). 9. The sauna oven of claim 5, c h a r a c ¬ t e r i z e d in that the groove (5) is narrow and deep in shape, and is arranged to circulate around the plate in two parallel grooves (5a, 5b) which are located at a distance (a) from each other and are united at one end.

Inventors: TELAMO ERKKI, TELAMO, ERKKI
Applicants: TELAMO ERKKI, TELAMO, ERKKI
Application year: 1989
Main classification: A61H33
IPC codes: A61H33