PL199707B1 - Heating unit and heating plate in this unit - Google Patents

Abstract

Heating device of the type which at least consists of a treatment space (2) equipped with a number of hot plates (3-4), either or not composed of several partial plates (3A-3B, 4A-4B), formed of a hollow sandwich structure with at least two plates (5-6) in between which can circulate a heating medium, as well as with means (8) to move a product to be heated over the hot plates (3-4), characterised in that at least a number of the above-mentioned hot plates (3-4), partial plates (3A-3B, 4A-4B) respectively, are placed mainly freely on a continuous supporting structure (16) situated each time underneath them. <IMAGE>

Description

Description of the invention

The subject of the invention is a heating device and a heating plate of this device used with it.

The present invention relates in particular to heating devices intended primarily for drying selected products, for example powders, grains and various types of organic and inorganic substances, such as sludge and the like, which devices can also be used for other purposes, such as toasting selected products. products.

More specifically, the invention relates to a heating device wherein at least a processing area can be distinguished in which, first, there is a plurality of heating plates, which may or may not be sub-plates that are characterized by a multi-layer structure, wherein at least two plates are used. between which a heating medium can circulate and, secondly, a suitable element, for example a distributing element or the like, by means of which the heated medium is distributed within the heating plates.

The heating plates are placed on top of each other horizontally, thereby forming a heating device with a number of levels. The heating plates are designed in such a way that the treated product can move radially outwards within the first heating plate by means of distributing means or the like. The product then drips from the edge of this plate onto the second heating plate below, within which it moves radially inward by means of spreading means or the like. The product then passes through the central openings to the lower heating plate. This cycle is repeated as many times as necessary to obtain a heating surface sufficient in size to exchange a certain amount of heat to allow the product to dry, toast, or similarly treat it before it enters a certain state.

A common problem with the use of hotplates or such partial plates is excessive bending due to external loads and self-weight, and the fact that due to the temperature differences that occur here, it is often difficult to limit or eliminate uneven expansion - especially when large-size hobs are used. The bending and deformation should not exceed a very narrow range as the gap that can be established between the distribution devices and the heating plates must not be greater than that allowed and established at the time of initial assembly.

To reduce this problem, as already described in the Belgian solution No. 1,013,426, it was proposed to support the heating plates - if possible - outside the insulated casing. Although this solution achieves satisfactory results, in particular, making it possible to reduce deformations due to temperature differences, the issue of bending still remains unresolved.

The subject of the invention is a heating device in which at least a processing area can be distinguished, in which, first, there are a number of heating plates, which are preferably sub-plates characterized by a multi-layer structure, in which at least two plates are used, between which the heating medium can circulate. . Moreover, the device comprises a suitable element by means of which the heated product is distributed over the surface of the heating plates, in which at least some of the heating plates or sub-plates are arranged substantially freely on a continuous supporting structure underneath each of them.

The essence of the invention is that the support structure comprises a positioning ring with a ring-shaped flange which fits into a groove provided in the heating plates or sub-plates.

Preferably, each support structure rests substantially freely on support points, in particular shafts or the like, the support structure may be a bar frame or the support structure being at least concentrically spaced bars and / or struts as well as longitudinally spaced members. radii, bars and / or expansion elements, the upper parts of which are arranged in the same plane.

In the device according to the invention, each support structure is fixed at substantially one point, which is one of the support points of the support frame, while being free to move at the other support points.

The device comprises one or more heating plates of radial structure which have a system of channels through which the heating medium is conveyed, the system allowing substantially radial circulation.

PL 199 707 B1

Partitions are placed in the heating plates, ensuring a zig-zag flow along the radii, while the heating plates are divided into sections, in particular partial sections, and one or more partial plates can be distinguished in them, in particular in the shape of circular sections, each of which is a half, a quarter or a smaller part of the hob.

The heating plate or each sub-plate has a system of channels which includes at least a supply pipe running below the heating plate, a circular distribution pipe on top near the center of the heating plate, and openings connecting the distribution pipe to the interspace of the sandwich structure and also circular. a collecting tube located near the outer periphery of the hotplate from the bottom of the hotplate, the tube communicating with the intermediate space via openings and at least one discharge tube communicating with the circular header tube.

There are bars in the heating plates, which enable the division into individual partial sections, the position of these bars being consistent with the position of the bars of the supporting structure running along the radii.

The subject of the invention is also a heating plate with a multilayer structure, in which at least two plates can be distinguished between which the heating medium can circulate, characterized in that it has a radial structure.

Advantageously, the plate according to the invention has a radial structure, the radial character of the structure being achieved by the fact that the heating plate comprises slice-shaped partial plates and the heating plate is equipped with a system of channels through which the heating medium circulates and which provides a flow along the radii. in addition, the heating plate can be divided into partitions which provide a zig-zag flow along the radii, the heating plate or sub-plate being divided into partial sections along the radii.

As each of the hot plates lies substantially freely on said support structure, the risk of deformation is reduced. Thereby, for example, there are no differences in tension between the support structure and the heating plates, whereby at least those deformations which could accompany this phenomenon are eliminated.

The term "substantially free support" of the cooktops and / or the support structure means that each cooktop and / or support structure is completely free to be supported, being at most to a limited extent, for example at one point. As far as the supporting structure is concerned, this may, for example, be the case for a single point of support, while in the case of a heating plate, only the fixing at the center point may be used.

According to a further advantageous embodiment of the present invention, said supporting structure is a bar frame, whereby the structure is light and durable.

Such a structure is characterized by high stability. All the bars are permanently in the zone where the temperature is equalized by the convection current caused by the swirling steam, as a result of which the expansion is uniform. As a result, loads can be absorbed by the superstructure according to the most favorable load transfer concept.

The substructure according to the invention is characterized by a perfectly flattened top, so that the load from the heating plate and the usual external load is transferred optimally to the supports of the enclosure body or the enclosure structure. As the load-bearing structure is characterized by considerable stiffness, the bending due to the load of the heating plates and the self-weight will be kept to a minimum.

Each load-bearing structure or sub-structure is preferably attached at one point at its edges to one of the supports which are part of the support frame, such structure being freely positioned on the other supports. Each heating plate or particle plate is preferably fixed to the center of the underlying substructure by means of a positioning ring. Such a ring is provided with an annular flange which is shaped to the groove with sufficient play, which groove is located in the center of the heating plate or the sub-plates. Moreover, the heating plates or the partial plates are placed freely on the supporting structure. As a result, no tensions arise between the heating plates, the underlying support structure and the enclosing body, while at the same time remaining in a substantially constant position relative to each other.

According to a particularly advantageous solution, the proposed structure according to the invention ensures maximum bending of the plates and their supporting structure under the influence of their own weight and normal external load at the level of 1/1750 to 1/2500 depending on the diameter of the plates.

PL 199 707 B1

The structure according to the invention does not allow for differences in voltage between individual elements under the influence of load or high temperature, and the connections between the individual elements enable the uniform transfer of stress caused by the load and high temperature to the entire structure of the device.

By using the construction according to the invention, a model of the circulation of the heating medium is obtained, according to which such medium flows through all the elements of the currently used heating plate, thus heating them to an almost identical degree, which allows for uniform expansion also during heating.

The heating plates, which have the basic properties already set out above, are preferably used in the device object of the present invention, which is characterized by a radial structure. Due to the structure of this type of device, this device gains stability in relation to the previously known solutions, and at the same time it is possible to construct plates of significant diameters without the risk of unacceptable bending or stressing the material. Moreover, this solution enables uniform expansion during heating.

The radial structure is preferably obtained by dividing the heating plate and / or the sub-plates constituting it into individual sections, each section having an angle of less than 90 [deg.] And preferably less than 30 [deg.]. Moreover, the heating plate is divided into at least two and preferably more independent sub-plates.

In heating plates, one can favorably distinguish bars that act as partitions, edges and other elements that allow division into individual sections. The position of these bars is consistent with the radii of the bars of the underlying substructure, thereby carefully supporting them.

According to the invention, very large hot plates can be constructed, with a diameter of more than 7 meters, reaching even 8 meters and more, and the sub-plates can be transported in the traditional way on public roads.

The heating plate and the underlying support structure preferably comprise two semicircular sections. It goes without saying that the sub-plates can also cover a smaller area, for example a quarter of a circle or a smaller segment thereof.

The use of circular sector elements allows not only to transport the heating plate in parts, but also for the assembly of relatively large heating plates to proceed symmetrically without major difficulties.

The underlying support structure can also be made of circular sector elements.

In order to ensure an optimal system of heat distribution within the heating plate and the supporting structure located below, each heating plate or its section is equipped with a system of channels, which can be distinguished at least: a supply pipe running below a multi-layer structure; a circular distribution pipe on top near the center of the heating plate; openings connecting the distribution pipe with the intermediate space of the sandwich structure; a circular collecting tube located adjacent to the outer periphery of the heating plate on the underside of the sandwich structure, which tube communicates with the intermediate space via openings; at least one discharge tube connecting to the circular collection tube.

An essential, albeit secondary, feature of the present invention is that for large sized hotplates, i.e. the above-mentioned plates provided with clearances close to the center, the heating elements are disposed not only in the portion located radially inside the clearances, but also in the portion located radially on the inside of the clearances. outside clearances. This means that the entire plate structure is heated evenly.

It should be noted that the present invention also relates to hotplates having the above-described radial structure, whether or not they are provided with a floating bearing, and regardless of how they are supported.

The subject of the invention is illustrated in an exemplary embodiment in the drawing, in which: Fig. 1 schematically shows a heating device according to the invention; figure 2 shows a plan view of the underlying substructure indicated by F2 in figure 1; figure 3 shows a bottom view of one of the so-called small hot plates, as indicated, for example, in figure 1 with F3; figure 4 shows the detail indicated by F4 in figure 3 on a larger scale; figure 5 shows a bottom view of one of the so-called large hot plates, as indicated, for example, in figure 1 by F5; figure 6 represents the part marked F6 in figure 5 to a larger scale; Fig. 7 is a section of the heating plate shown in Fig. 5 along line VII-VII in the drawing

The associated part of the underlying substructure is also taken into account; figures 8, 9 and 10 show to a larger scale the parts indicated in figure 7 by F8, F9 and F10; Figures 11, 12, 13 and 14 are enlarged sections taken along the lines XI-XI, XII-XII, XIII-XIII and XIV-XIV in Figure 6; Fig. 15 is a top view of a hotplate with four sub-plates.

As shown simplified in Fig. 1 and in detail in Figs. 2-14, the present invention relates to a heating device 1 in which at least a treatment area 2 can be distinguished, in which, first, there are a number of heating plates 3. -4, characterized by a multi-layer structure, where at least two heating plates 5-6 are used, between which there is an intermediate space 7, where a heating medium may circulate, for example steam or a heated liquid such as oil, and, secondly, a suitable element 8, with the help of which the heated product is distributed along the heating plates 3-4.

The hot plates 3, also referred to as small hot plates, allow the dried product to be carried over their surface, from the center to the outer edge, from where the product drips onto the hotplate 4 below. The hotplates 4, also referred to as large hotplates, have lumen 9. The product is transferred over their surface from the outer edge to the center where the product drips through the lumen 9 onto the small hotplate 3 below.

The element 8 mentioned here comprises a distribution mechanism 10 in which, first, a central shaft 11 can be distinguished, which extends through the central openings 12 and 13 in the heating plates 3 and 4 and is provided with the distribution means 14 moving over the surface of the heating plates 3-4, and secondly, a driving element 15, such as an electric motor, responsible for driving the shaft 11.

According to the present invention, at least a certain number of the heating plates 3 to 4, or the sub-plates from which they are made, are arranged substantially freely on a continuous supporting structure 16 arranged thereunder.

Each support structure 16 also rests substantially freely on support points 17 arranged at the periphery of the processing area 2 and which form part of the support frame 18. In the present case, the support is provided by roller bearings, in particular shafts 19 or the like.

As shown in Fig. 2, the supporting structure 16 is a frame made of bars, in particular radial bars, in this case main bars 20-21, as well as concentric bars, in this case annular bars 22, and intermediate bars. 23.

The support structure 16 is made of two semicircular sub-structures or, in accordance with another solution not shown in the drawing, a greater number of segment-shaped circular structures.

The aforementioned radial main bars 20-21 include a plurality of radial IPN or HEB bars 20, and on the parting side, i.e. the side edges of the substructures 24-25, U-bars 21, the core plates 26 of the opposing bars 21 are connected to each other. in pairs using bolt connections 27, forming a whole within one level. In turn, the above-mentioned ring bars 22 are U-bars. Four ring structures 28-29-30-31 are formed with the bars 22, one along the inner edge and the other along the outer edge. The two outermost ring structures 29-30 are made of U-bars, while the ring structure 28 is formed of U-bars. In the example given, the intermediate bars 23 are HEB crossbeams or U-bars depending on the diameter of the heating plates.

The top of the substructure 16 has been carefully aligned. Thus, excellent support for 3-4 heating plates was obtained.

According to a preferred embodiment, the sub-structures 24-25 are also attached to each other within a given level by contact strips not shown, which are welded to the ends of the bars 21 placed opposite each other after the sub-structures 24-25 are joined.

It should be noted that each substructure 16 and / or substructure 24-25 is preferably permanently attached at one point along the outer edge to one of the supports 17, while being loosely placed on the other supports 17, possibly with the use of roller bearings 19. Note that each cooktop 3-4 - and in the event that they include sub-plates, for example 3A, 3B and so on, or 4A, 4B and so on, each plate

The partial - is preferably arranged substantially centrally on the substructure 16 associated with it, preferably resting on the substructure so that it can move freely. Proper positioning of the heating plates 3-4 or the partial plates 3A-3B, 4A-4B on the support structure 16 can be achieved, as shown in Fig. 8, by joining the positioning ring 51 to the central structure 50, in particular a sleeve structure within. a support structure, which ring can be distinguished by an annular flange 22 fitted to the groove 53 with sufficient play, which groove is located in the center of the heating plate or the sub-plates. A construction of this type allows to ensure a constant mutual position between the plate and the supporting structure 16. The positioning connection of the heating plates 3-4, 3A-3B, 4A-4B with the supporting structure 16 is responsible for securing the fixed position of the plates and prevents their accidental displacement, for example as a result of contact with the distributing elements 14, or due to differences in expansion with respect to the supporting structure 16. The interconnection of the partial heating plates may use common contact strips, not shown in the drawing, and which can be placed on the side joining the partial plates to each other - centrally along the outer edge.

In a similar manner, each support structure 16 is preferably permanently attached to one point - one of the support points 17.

While the present invention envisages the use of any type of hotplate 3-4, it is preferred to use hotplates of the type discussed with reference to Figures 3-14.

The heating plates 3-4 shown in the drawings include two semicircular particle plates 3A-3B, 4A-4B which are supported side by side substantially freely, as will be discussed below. Many of the features described below also apply to a solution not shown in the drawings which provides for the use of multi-piece heating plates 3-4 divided into sections, as shown, for example, in Fig. 15, as well as for the solution according to which such a plate is made. in the form of one element.

The accompanying drawings first show the general construction of both plates 3 and 4, with small hotplates 3 shown in Figures 3-4 and large hotplates 4 in Figures 5-14.

As shown in the figures, each heating plate 3-4 is characterized by a multi-layer structure, where 5-6 plates can be distinguished. Each of the sub-plates 3A-3B, 4A-4B is bounded along the entire edge by strips 32 connected to the plates 5 and 6 by welded joints.

The basic feature of the heating plates 3-4, and thus the sub-plates 3A-3B, 4A-4B, is their radial structure, which structure can be manifested in various ways, as will be described below.

According to a first embodiment, the radial structure relates to heating plates 3-4, divided along the radii into sections 33, each having an angle A of less than 90 °, preferably 30 ° or less. Such a structure was achieved thanks to the division of the intermediate space with the use of partitions 34.

Another essential feature of the heating plates 3-4, emphasizing the already mentioned radial nature of the structure, is that the plates are provided with a system of channels through which the heating medium circulates substantially along the radii, in particular independently within each sector 33. This radial type of circulation is indicated in 4 and 6 by arrows 35.

Circulation of this type means that the heating medium moves substantially within the sector, starting from the center to the outside as in the present example, or, alternatively, from outside to inside within the intermediate space 7, preferably along a system of radially spaced channels. .

As shown in Figures 4 and 6, baffles 36 are also advantageously taken into account between the plates 5 and 6. They not only have a radial flow, but also provide a zig-zag flow along the radii, resulting in a more uniform heating system.

As shown, inter alia, in Figs. 11 and 12, the baffles 34 and 36 are slats made in the form of individual rectangular bars arranged vertically.

In the present example, the baffles 34 and the radially spaced slats 32 along the side edges of the sub-plates 3A-3B, 4A-4B are routed above or substantially above the radial main bars 20 and 21 of the support structure 16.

PL 199 707 B1

As shown in Figures 4 and 6, additional local spacer sleeves 37 can be placed between the plates 5 and 6.

Each particle board 3A-3B, 4A-4B has a channel system that includes at least: a feed pipe 38 extending below the sandwich structure; a circular distribution tube 39 on top near the center of the particle plate; openings 40 connecting the distribution pipe 39 to the intermediate space 7 of the multi-layer structure; a circular collection tube 41 located close to the outer periphery of the partial plate on the underside of the sandwich structure, which tube communicates with the intermediate space 7 via openings 42; at least one discharge tube 43 communicating with the circular collection tube 41.

According to the presented solution of the small heating plate 3, each part of the intermediate space 7 that is delimited by the partial section 33 extends continuously from the circular distribution pipe 39 to the circular manifold 41.

The distribution pipe 39 and the collection pipe 41 are preferably made of semicircular pipes which, as shown in FIGS. 7-10, connect on their flat side to the multilayer structure, which allows the overall height to be limited.

From the attached drawings it can be seen that the above description applies to each of the sub-plates. Therefore, when a one-piece heater plate 3-4 is used, it is obvious that the pipes 39-41 may include a full circle rather than a semicircle, with more than one feed pipe 38 and discharge pipe 43 being possible.

During the operation of the heating device 1, the heating plates 3-4 are heated by passing the heating medium through the supply pipes 38 to the sub-plates 3A-3B, 4A-4B. The heating medium then flows through the separating pipes 39 and through the groove-shaped openings 42 into the interspace, from where it is discharged in a zigzag pattern within the partial sector 33 towards the openings 42. This medium, flowing through the openings 42, accumulates in the collecting pipes 41, from where it can be removed through drain pipes 43.

As stated above, the design of the small cooktops 3 corresponds to that of the large cooktops 4. The differences between them are summarized below.

The first design difference is that the small heating plates 3 have a smaller outer circumference. This also applies to the corresponding support structure 16, the outer edge 44 of which is completely hidden under the cooktop 3. The support structure 16 of a small cooktop can here be of the same size as that of the large support panels. Then the only difference is that the annular structure 29 is located closer to the annular structure 30. The clearance 45 in the treatment space 2 of the heating system thus remains completely free, except for the supports 17 extending from the support frame 18. It should be noted here that the supports 17 are arranged they are also under the substructure 16 on the lower level. There are no clearances in the heating plates 3, while in the large heating plates 4 clearances 9 are taken into account, the position of which corresponds to the position of the clearances 46 in the supporting structure 16.

A second significant difference lies in the fact that, in the case of large hot plates 4, the intermediate space 7 corresponding to the section 33 in question is divided into two parts 47 and 48 due to the presence of clearances 9, while in the large hotplate 4 it is possible to distinguish between channels 49 connecting the first part. 47 of the intermediate space 7 with the second part 48.

It should be noted that in the center of the support structure 16 a sleeve structure 50 as shown in Figs. 7 and Fig. 8 has been placed and fastened thereto. In this design, a sleeve 52 can be distinguished with two welded flanges 54 surrounding the annular structure 28 of the substructures 24. and 25, which is made of U-bars, the flanges 54 are welded to the radial balcony 20 and 21 of the support structure 16. Partial support structures 24 and 25 can be joined by lap belts 55 of limited size welded to the U-elements. -shaped annular structure 28 at the height of the partition between the sub-structures 24 and 25. A positioning ring 51 of hot plates 3-4 is connected to the upper flange 54.

The heating device 1 operates essentially as follows.

The heated product is conveyed over the surface of the heating plates by distributing means 14, this product being directed in a known manner along the surface of the heating plates 3 from the center towards the outer edge and along the surface of the large heating plates 4 from the outer edge to the center. During this movement, the product drips

From one higher-positioned heating plate to another below-lying heating plate, thus moving in a zigzag pattern within the heating device 1.

During the operation of the device, the heating medium is transferred to the circular distribution pipe 39 each of the supply pipes 38, from where the heating medium flows into the intermediate space 7 through the openings 40. After the heating medium flows through the intermediate space 7 according to the above-mentioned zigzag flow model this medium leaves the space 7 through the openings 42, entering the collecting pipe 41, from where it is removed through a discharge pipe 43, for example to a heating medium heating device.

Since, in the case where the heating medium is steam, it is necessary to supply less condensed water vapor within a given sector, a simpler solution provides for a less complicated structure. It is not recommended to use the zigzag flow model then. The preferred solution in the case of using steam is to pass it through a circular distribution pipe along the outer periphery of the heating plates 3-4, and in the case of condensates, to remove them by means of a circular discharge pipe located in the center.

Finally, it should also be noted that the term "circulation essentially along radii" means that the heating medium is transferred from the outside to the center or vice versa within the given segment. However, within each sector, the flow may be arbitrary, not necessarily following the indications of the arrows 35 in Fig. 6.

In turn, the term "continuous support structure 16" according to the invention means any supporting structure located below the heating plate 3 or 4 (as opposed to, for example, local supports located only along the edge), irrespective of the structure of the supporting structure 16.

It is clear that, thanks to the particular type of construction according to the invention, a great deal of freedom of movement is allowed between its individual elements, which allows for optimal compensation of expansion differences, within each element, in particular within the heating plate 3 or 4, and within each supporting structure 16, a uniform expansion system has been achieved, so that these elements are not subject to undesirable bending.

From Fig. 15 it is clear that the heating plates need not be made of two sub-plates, instead being made of four or more such plates.

The present invention is not limited to the above-mentioned embodiments, which are merely exemplified in the drawing. The heating device as well as the heating plates according to the invention can be made in various shapes and with different dimensions, without thereby departing from the scope of the present invention.

Claims (14)

Patent claims 1.Heating device in which at least a treatment area can be distinguished, in which, first, there are a number of heating plates, which are preferably sub-plates characterized by a multi-layer structure, where at least two plates are used, between which a heating medium can circulate, and, secondly, a suitable element by which the heated product is distributed over the surface of the heating plates, wherein at least some of the heating plates or sub-plates are arranged substantially freely on a continuous supporting structure underneath each of them, characterized by that the support structure (16) includes a positioning ring (51) with a ring-shaped flange (52) that fits into a groove (53) provided in the heating plates (3-4) or sub-plates (3A-3B, 4A-4B ). 2. The device according to claim The support structure of claim 1, characterized in that each support structure (16) rests substantially freely on support points (17), preferably rollers or the like. 3. The device according to claim 1 A bar as claimed in claim 1 or 2, characterized in that the supporting structure (16) is a frame made of rods. 4. The device according to claim 1 The structure according to claim 1 or 2, characterized in that the supporting structure (16) comprises at least concentrically spaced bars (22-23) and / or expansion elements as well as radially spaced bars (20) and / or expansion elements, the upper parts of which are arranged in the same plane. PL 199 707 B1 5. Device according to claim 1 or 2, characterized in that each support structure (16) is fixed at substantially one point, being one of the support points (17) of the support frame (18), while being free to move at the other support points (17). . 6. Device according to claim The apparatus of claim 1, characterized in that it comprises one or more heating plates (3-4) of radial structure. 7. The device according to claim 1 6. Device as claimed in claim 6, characterized in that the heating plates (3-4) have a system of channels through which the heating medium is conveyed, the system allowing substantially radial circulation. 8. The device according to claim 1 6. The method according to claim 6 or 7, characterized in that partitions (36) are provided in the heating plates (3-4), ensuring a zig-zag flow along the radii. 9. The device according to claim 1 6. The method of claim 6, characterized in that the heating plates (3-4) are divided into slices, in particular partial slices (33). 10. The device according to claim 1 6. A method according to claim 6, characterized in that it comprises heating plates (3-4) in which one or more particle plates (3A-3B, 4A-4B) can be distinguished, in particular in the shape of circular sections, of which each is a half, a quarter or less of the heating plate (3-4). 11. The device according to claim 1 6 or 10, characterized in that the heating plate (34) or each sub-plate (3A-3B, 4A-4B) has a channel system in which at least a supply pipe (38) can be distinguished below the heating plate (3-4), a circular manifold (39) on top near the center of the heating plate (3-4) and openings (40) connecting the manifold (39) to the intermediate space (7) of the sandwich structure, and furthermore a circular manifold (41) located near the outer periphery of the hotplate (3-4) on the underside of the hotplate (3-4), which tube connects to the intermediate space (7) through openings (42) and at least one discharge tube (43) connects to a circular the header pipe (41). 12. The device according to claim 1, 6. A method according to claim 6, characterized in that the heating plates (3-4) have bars that enable the division into individual partial sections (33), the position of these bars being consistent with the position of the bars (20) of the supporting structure (16) running along the radii. . 13. A multi-layer heating plate where at least two plates can be distinguished between which the heating medium can circulate, characterized in that it has a radial structure. 14. The board according to p. 13, characterized in that it is characterized by a radial structure, the radial character of the structure being achieved due to the fact that the heating panel (3-4) comprises partial plates (3A-3B, 4A-4B) in the shape of sections and a heating plate ( 3-4) is equipped with a system of channels through which the heating medium circulates and which ensures the flow along the rays, and the heating plate (3-4) also features partitions (36), ensuring a zig-zag flow along the rays, while the heating plate (3-4) or a sub-plate (3A-3B, 4A-4B) has been divided along radii into partial sections (33).