The invention relates to a heating apparatus utilizing solar energy, said apparatus comprising a stand and a device sup- ^" ported by said stand for concentrating the rays of the sun and directing them to a predetermined limited area.

Heating apparati utilizing solar energy are previously known in different forms. There is, however, a great need for such an apparatus which is simple and inexpensive as well as being easily assembled, so that it can be used for heating, e.g. for ςooking purposes, in any location where the user happens to be.

The purpose of the present invention is to achieve an appara¬ tus of the type described by way of introduction which ful- fills the above described needs and also has additional advantages.

This is achieved by an apparatus which has those features disclosed in the characterizing clause of the accompanying claim 1.

Advantageous embodiments of the invention are disclosed in the subclaims.

The invention will be described in more detail below with reference to the accompanying drawings, which show as examples two embodiments of the apparatus according to the invention and in which,

Fig 1 is a schematic perspective view of an apparatus according to a first embodiment of the invention, Fig 2 shows a schematic vertical section through the apparatus according to Fig 1, Fig 3 is a schematic perspective view of an apparatus according to a second embodiment of the invention, and

Fig 4 shows a schematic section through the apparatus according to Fig 3.

Fig 1 shows an apparatus according to a first embodiment of the invention. The apparatus is made of three main compo¬ nents, viz. a stand 1, a reflector 2 and a heat storage means 3.

The stand 1 is of simple construction and consists essenti¬ ally of a pole 4, which is provided at its lower end with a support means 5 (see Figure 2) , which are intended to rest on the ground or be pushed into the ground to support the stand 1 in the desired direction relative to the sun. At its upper end, the pole 4 supports the heat storage means 3, which comprise a heat storage body 6, which is removably mounted on the pole 4. The heat storage body 6 is made of a material with good heat storage capacity, e.g. cast iron or the like.

The reflector 2 shown in Figs 1 and 2 is made of one or more panels 7 of plastics material. The panels 7, of which only one is shown in Fig 1, are made of a relatively thin plastics material, suitably with a thickness of 1-2 mm. This plastics material is pressed in a specially designed tool to achieve the form which is shown schematically in the drawing. This means that each panel 7 is provided with a large number of arcuate grooves 8 with their common center essentially at the pole 4. The grooves 8 are individually made so that incident sunlight will be reflected towards an essentially common focus, which is located in the vicinity of the underside of the heat storage body 6, as will be described in more detail below.

Each panel 7 is also coated on its topside with a thin layer of aluminum or another reflecting material. This coating can be done with the aid of known processes, used in the packa¬ ging industry for example. These processes can achieve a mirror surface which reflects essentially 100% of the incom- ing sunlight. In this manner it is also possible to make a very inexpensive panel 7, which can also be rolled together so as to take very little space and be easily protected against damage when it is not being used.

The grooves 8 in each panel 7 are made so that the rays of the sun are reflected to a focus in the vicinity of the underside of the heat storage body 6 . The temperature at the focus can become so high when the apparatus is used that it can damage the heat storage body 6. In order to avoid this, the grooves 8 in the panels 7 are suitably made so that the reflected rays strike the heat storage body 6 over a surface which is of limited size. The pole 4 can also have such dimensions that the distance between the panels 7 and the heat storage body 6 is approximately twice as long as the side of one of the square panels 7. This provides a design where the individual grooves 8 in each panel 7 will throw as small a shadow as possible.

Fig 2 shows fastening means for fixing the panels 7 to the pole . These fastening means can be made in various manners and the intention is that the panel 7 is to be detachably clamped to the pole 4. Fig 1 shows as well holder means 10 for the panels 7. These holder means 10 consist of some type of clamping molding to keep the panels 7 flat and correctly oriented relative to the pole 4. The holder means 10 are joined together by means of corner pieces 11 and connecting pieces 12, which can be made in a known manner.

In order to avoid too much heat dissipation from the heat storage body 6, it is covered with an insulating cover 13. This is made so that it covers the heat storage body 6 on all sides except the underside. The insulating cover 13 is made of a material with very good insulation properties, e.g. cellular plastic or the like. This means that the heat radiated from the heat storage body 6 will be as small as possible, so that the temperature of the heat storage body 6 can be raised very rapidly when the apparatus is used.

Figs 3 and 4 show a second embodiment of the apparatus according to the invention. In this embodiment there is a stand 14, which has a pole 15 which can be pressed down into the ground, so that the apparatus is kept in a predetermined position. The stand 14 also comprises an adjustment device

16 on which a pole 4a, corresponding to the pole 4 in the embodiment according to Fig 1, is mounted. The pole 4a supports in turn a heat storage body 6a at its distal end.

A reflector 2a is fixed to the adjustment means 16 and consists of a plurality of panels 7a, which form together a cone. Each panel 7a is provided, as were the panels 7 in the embodiment shown in Figs 1 and 2, with a large number of grooves 8a, making it possible to reflect incident rays of the sun towards a focus which is located in the same manner relative to the heat storage body 6a as in the embodiment according to Figs 1 and 2.

The adjustment means 16 make it possible to direct the reflector 2a in a suitable manner relative to the sun.

In this embodiment as well, the heat storage body 6a can be provided with an insulation cover corresponding to the insulation cover 13 in the embodiment shown in Figs 1 and 2.

The panels 7a are placed in holder means 10a in a manner corresponding to that described above in connection with the embodiment shown in Figs 1 and 2. The holder means 10a are connected to the pole 4a or to the adjustment means 16. The panels 7a and the holder means 10a form together a cone for effective reflection of incident sunlight and concentration of the radiation to the underside of the heat storage body 6a. It should also be pointed out in this context that the design of the reflector 2a as a cone makes it possible to utilize the incident solar energy even more effectively. By properly selecting the cone angle and the length of the pole 4a, it is possible to reduce the number of grooves, at least in the outer portion. Thus, the formation of shadows will be less and the efficiency will be increased.

As mentioned above, the panels 7 or 7a in the apparatus according to the invention are made with a large number of grooves to reflect the sunlight and concentrate it to the underside of the heat storage body 6 or 6a. This means that the panels 7 or 7a are made as the counterparts to so-called

Fresnel lenses. This makes it possible to make the panels 7 or 7a in thin material which is flexible in order to be able to be rolled up when the apparatus is not being used.

The apparatus according to the invention is primarily intended to be used for cooking, and for this purpose, the heated heat storage body 6 or 6a is removed from the apparatus and placed on a supporting surface of some type. Thereafter, a cooking vessel can be placed on the heat storage body 6 or 6a for cooking purposes. It is also possible to use the heat storage body 6 or 6a at a later point in time, and in this case the heat storage body should be kept in a very well insulated box or the like in order to minimize heat loss.

The invention is of course not limited to the above described embodiments, rather changes can be made within the scope of the following claims.