Food preparation utensil with its bottom protected against deformation

The subject of the invention is a dish for preparing food.

There are known dishes for preparing dishes in which attempts have been made to eliminate the phenomenon of bottom deformation caused by thermal phenomena.

Known dishes are generally extruded from a single sheet of aluminum sheet. When heating such dishes, the outer surface of the bottom in contact with the hob or burner is exposed to a much higher temperature than the inner surface of the bottom. This leads to thermal expansion of the bottom of the vessel and its bulging. To eliminate this troublesome phenomenon, the bottom of the dish is given a slightly concave shape so that when heating the bottom, it expands and takes a substantially flat shape. During cooling, the bottom of the dish theoretically regains its concave shape. Experience shows, however, that as a result of repeated repetition of heating and cooling operations, the bottom concavity decreases, then the bottom assumes a flat shape, until it finally bulges and the vessel becomes practically useless. This phenomenon is due to the properties of aluminum. During subsequent heating and cooling operations, the range of elastic deformations is exceeded, which in turn leads to irreversible deformation.

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The object of the present invention is to eliminate the irreversible deformation of the bottom of the dish for the preparation of dishes made of a sheet of metal or a light alloy, for example aluminum.

The dish for preparing dishes made of a single disc of metallic material and having a slightly concave bottom placed on a hot plate, according to the invention is characterized in that a bottom plate is attached to the bottom protecting part of the bottom and of metallic material having different mechanical, thermal and physical properties than the material metallic shield.

Preferably, the board is divided into sectors.

Preferably, the vessel is formed of one aluminum sheet of shield and the plate is steel.

Preferably, the bottom has a bearing surface positioned around the plate extending above the outer surface of the plate.

Preferably, the tile covers from 5 to 30% of the bottom surface.

Preferably the plate has holes and is partially embedded in the bottom.

Preferably, the thickness of the tile is in the range of 3/10 to 5/10 mm, and the tile is embedded in the bottom to a depth of 0.5 / 10 to 1.5 / 10 mm, the thickness of the aluminum bottom is from 2.5 to 10 5 mm.

Preferably, the tile adheres to the bottom groove.

Preferably, the plate has a disk or ring shape preferably divided into a number of segments.

Preferably the plate is centrally located in the bottom of the vessel.

Preferably, the plate is eccentrically located in the bottom of the vessel.

Preferably, the plate holes have a dimension smaller than twice the distance between them.

Preferably, the holes have a diameter of about 3 mm and the gap between the two holes is about 2 mm.

By embedding the plate in a specific zone of the bottom of the dish and due to the fact that its mechanical, thermal and physical properties differ from those of the metal or metal alloy forming the remaining part of the dish, all irreversible deformations of the bottom of the dish are eliminated, even if it has been repeatedly subjected to subsequent heating and cooling operations . Tests have shown that it is important that the plate described above is mounted only on a small part of the bottom. The concavity of the bottom in which the plate is placed is preferably made at the time of extruding the disk from a metal or light metal alloy in which the said plate has been fully or partially embedded previously. The main component of the metal or metal alloy from which the vessel is made is generally aluminum, and the plate, wholly or partly embedded in the bottom, is generally steel, preferably stainless steel. A groove can be made around the circumference of the plate. Preferably, the plate has holes and is fully or partially embedded in the bottom in such a way that the bottom metal completely fills the holes. This insertion of the tile causes it to protrude slightly beyond the bottom surface. The tile can be embedded in the bottom material by cold pressing. Too deep embedding of the plate in the bottom metal proves to be harmful.

The subject of the invention is shown in the embodiment in the drawing, in which Fig. 1 shows a plan view of a disk intended for extrusion into the shape of a vessel, Fig. 2 said cross-section of the disk.

Figures 1 and 2 show a disk 3 cut from a sheet of metal or a light alloy, e.g. aluminum. The disc 3 is pressed in a known manner in order to obtain a dish for preparing dishes, for example a pan or saucepan, with a bottom to be placed on a hob or burner. In Figure 1 the circle C marked with dashed lines defines the circumference of the bottom 1 of the vessel. The bottom 1 is made during extrusion of the disk 3 with a slight convexity. The bottom 1 has in its central part a plate 2 of metal or metal alloy with different properties than the metal or alloy from which the disk 3 is made. The plate 2 is, as can be seen in Fig. 2, the bottom 1 embedded in the metal and the peripheral part 2a of the plate 2 adheres to the groove 4 made in the bottom 1. After extrusion of the disk 3, the bottom 1 has a bearing surface 5 arranged around the tile 2 protruding above the outer surface of the tile 2, so the convexity of bottom 1 is such that

174 642 dishes on the hob The bottom surface 5 around the plate 2 is in contact with the hot plate, while the plate 2 is not in contact with it. The disc 3 is made of 2.5 to 5 mm thick aluminum. Plate 2 is made of stainless steel and covers from 5 to 30% of bottom 1 surface. The small surface area of ​​the bottom 1 by the plate 2 provides the best results both in terms of bottom 1's resistance to deformation under the influence of subsequent heating and cooling operations as well as in terms of heat conduction and temperature distribution. These results are the result of partial embedding of the plate 2 in the central zone of the bottom 1 of the vessel and other steel properties in relation to aluminum, which means that the deformation does not become irreversible under the influence of subsequent heating and cooling operations.

In the embodiment shown in Figs. 1 and 2, the plate 2 has round holes 6 evenly spaced and at equal distances from each other over the entire surface of the plate 2. The plate 2 is partially embedded in the bottom 1 by cold-pressing. In this way, the plate 2 is permanently connected to the bottom 1 of the vessel at many points and limits any deformation of the bottom 1 due to the fact that it is made of steel. In the selected embodiment, in the case of a 1 aluminum bottom with a thickness in the range from 2.5 to 5 mm, the thickness of the plate 2 is in the range from 3/10 to 5/10 mm, and the plate 2 is embedded in the bottom 1 on depth from 0.5 / 10 to 1.5 / 10 mm. As can be seen in Fig. 1, the plate 2 has the shape of a disk. It could also be in the shape of a polygon or ring. Tile 2 can be divided into a number of sectors or be made in the form of a grid. The size of the holes 6 of the plate 2 is not critical, preferably the holes 6 of the plate 2 have a diameter smaller than twice the distance between the holes. In the given embodiment, the holes 6 have a diameter of about 3 mm and the distance between the two holes 6 is about 2 mm.

The following are comparative results between two pans, one of which is made in a conventional manner and the other according to the invention. Both pans had identical dimensions and were made using a 3.4 mm thick aluminum disc. A round stainless steel plate 0.5 mm thick and 75 mm in diameter was installed in the bottom of the pan according to the invention. Both pans were subjected to further rapid heating and cooling processes (heating to 250 ° C, followed by cooling in a stream of tap water to a temperature of about 20 ° C. After the thirty operations mentioned above, the bottom of the conventional pan was irreversibly deformed. In the case of the pan according to the invention irreversible bottom deformation was found only after 300 heating and cooling operations.

The plate 2 can have any shape and does not have to be centrally located in the bottom of the dish. For example, tile 2 can be star-shaped with any number of arms. The plate may be asymmetrical and have the shape of, for example, an arm running for example towards the vessel handle.

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FIG. 2

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FIG.1

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