DE102020116749B3 - Heating roller for a preheating cabinet and its production, preheating cabinet and this comprehensive system - Google Patents

Abstract

The invention relates to a heating roller (1) for providing a desired surface temperature for controlling the temperature of a material web (20) rotating around the heating roller, a preheating cabinet (10) with such a heating roller, a system (100) with such a preheating cabinet and a method (200) for the production of such a heating roller, which comprises a circular cylindrical casing tube (2) made of thermally conductive material, preferably metal, and at least one electrical heating mat (3) which is arranged on an inside (21) of the casing tube in contact with the casing tube, with one a thermal insulation layer (4) is arranged on the inside (31) of the heating mat not facing the jacket tube and a spreading device (5) is arranged on an inside (41) of the heat insulation layer inside the jacket tube, which exerts a pre-tension on the heating mat via the heat insulation layer, so that an outer side (32) of the at least one heating mat facing the jacket tube te is pressed permanently against the inside of the jacket pipe.

Description

Field of the invention

The invention relates to a heating roller for providing a desired surface temperature for controlling the temperature of a material web rotating around the heating roller with at least one heating mat, a spreading device and a thermal insulation layer. The invention further relates to a preheating cabinet with such a heating roller, a system with such a preheating cabinet and a method for producing such a heating roller.

Background of the invention

Heated rollers are used in a wide variety of processes for the pre- and post-treatment of materials that, for example, revolve around these rollers as a material web and are processed, heated or, if necessary, cooled to the roller temperature according to the roller temperature.

For a thermoforming process in the context of plastics processing, for example, the plastic films to be processed must be uniformly preheated to a certain temperature (for example 110 ° to 130 ° C.) before the actual thermoforming process. This preheating usually takes place in so-called preheating cabinets, such as in DE 101 51 799 B4 disclosed. Here, continuously working roller preheaters are used for preheating, which consist of two or four heated rollers, depending on the film thickness and feed speed. For heating purposes, the film is guided around the individual rollers in an S-shape with a large angle of wrap and absorbs the required heat from them while the film is being pulled through.

It would be desirable here if the heat transfer from the heating rollers to the plastic film takes place as uniformly as possible. DE 10 2015 005 066 A1 proposes to keep the tension that prevails in the plastic film when the plastic film is moved around the at least one heating roller in the preheating process. This can be achieved if the movement of the plastic film is not carried out solely by a transport roller after the at least one heating roller, but rather a further transport roller is arranged in front of the at least one heating roller. These two transport rollers together ensure that the plastic film moves at a constant speed. The drives of the transport rollers are equipped with control options and ensure that the tension in the plastic film remains constant.

The DE 30 33 689 discloses an electrically heatable roller, an inner tube and an outer tube arranged coaxially at a distance from the inner tube delimiting an annular space in which a plurality of butted heating mats are inserted distributed over the circumference. The outer tube forms the roll shell.

For example, thermal oils, electric heating cartridges or heating mats can be used in the heating rollers to heat the heating rollers. Uniform heating of the heating roller along its width and along its circumference is important for homogeneous temperature control of the material web, for example as homogeneous heating of a plastic film as possible for a subsequent thermoforming process, especially for thermoforming processes and the products resulting from them. The use of heating mats already leads to an improved homogeneity of the temperature on the surface of the heating rollers compared to heating the heating rollers by means of heating cartridges. However, the thermal contact between the heating mat and the roller material to be tempered can deteriorate due to thermal expansion during operation, so that the heating rollers are damaged in the event of insufficient heat transfer to the heating roller surface itself, so that the service life of the heating mats in the heating rollers is limited.

It would therefore be desirable to provide heating rollers for preheating cabinets, in particular for plastics processing machines, which can be heated as homogeneously as possible and whose heating means have a long service life.

Summary of the invention

It is therefore an object of the invention to provide a heating roller for preheating cabinets, in particular for plastics processing machines, which can be heated as homogeneously as possible and the heating means of which has a long service life.

This object is achieved by a heating roller for providing a desired surface temperature for controlling the temperature of a material web circulating around the heating roller, the heating roller being a circular cylindrical casing tube made of thermally conductive material, preferably metal, and at least one electrical heating mat that is in contact with the casing tube on the inside of the casing tube is arranged, comprises, wherein a heat insulation layer is arranged on an inside of the heating mat not facing the jacket tube and a spreading device is arranged on an inside of the jacket tube on an inside of the heat insulation layer, which a preload over the Heat insulation layer exerts on the heating mat, so that an outer side of the at least one heating mat facing the jacket pipe is pressed permanently against the inside of the jacket pipe.

The term “material web” denotes a two-dimensional material, for example provided by a roll, for rotating around the heating roller. The material can be any material suitable for revolving around a roll in a manufacturing process. For example, the material is a plastic film which is provided as a plastic web from a roll wound with the plastic web and which rotates around the heating roller. The plastic film can consist of different plastic materials depending on the process.

A heating roller provides a desired surface temperature for controlling the temperature of a material web rotating around the heating roller. Here, depending on the temperature of the circulating material web, it can be heated or cooled by the heating roller. The term “heating roller” here refers to the fact that the surface temperature of the heating roller is above the ambient temperature during operation. In the case of even warmer material webs, these can be cooled by the heating roller; in the case of material webs that are cooler than the heating roller, they are heated by the heating roller. The temperature of the material web takes place by means of heat transfer through contact of the material web with the surface of the heating roller while rotating around the heating roller. A large contact surface of the material web with the heating roller enables a more effective heat transfer, so that the material web preferably rests on at least half the surface area of the heating roller.

For this purpose, the jacket tube of the heating roller is made of a material that conducts heat as well as possible, for example metal, preferably steel. Since greater forces are exerted on the heating roller in the case of wider material webs, the material thickness of the jacket pipe is adapted accordingly.

Electric heating mats have the advantage over other heating means that they can transfer the generated heat to the heating roller over a large area. However, the quality of the heat transfer depends on the quality of the mechanical contact between the heating mat (s) and the inside of the jacket pipe. In the case of heating mats only attached to the jacket tube without any other devices attached inside the jacket tube, the quality of the thermal contact varies greatly locally, so that on the one hand the surface temperature of the heating roller varies both along the circumference and across its width and, on the other hand, the thermal energy generated everywhere in the heating mat does not increase uniformly the heating roller can flow off, so that strong local overheating of the heating mat (s) can occur, which can lead to damage or even destruction of the heating mat (s). Therefore, a precisely defined thermal contact between the heating mat (s) and the jacket tube of the heating roller, which must be kept as stable as possible over the operating period, is necessary. Surprisingly, it was found that not just tensioning the conventional heating mat (s) is sufficient for a uniform and long-term sufficiently good heat transfer, but that a thermal insulation layer should be arranged on the inside of the heating mat in order, on the one hand, to increase the heating power of the heating mat essentially in the direction of the jacket pipe and not to pass them on to the heating mat (s) on the inside of the heating roller (s) which are caused by the operation and which also locally vary in terms of time and space, which further improves the homogeneity of the surface temperature of the heating roller. In addition, the bias voltage generated by the spreading device is evenly transferred to the heating mat (s) via the thermal insulation layer, which enables a sufficiently uniform thermal contact of the heating mat (s) via the inside of the jacket tube of the heating roller. In this way, the heating roller is heated homogeneously from the inside and a long service life of the heating mat (s) is made possible by avoiding local overheating due to insufficient thermal contact with the jacket pipe.

Thus, a heating roller for preheating cabinets, in particular for plastics processing machines, is made available, which can be heated as homogeneously as possible and the heating means of which has a long service life.

It should be expressly pointed out that in the context of the present patent application, indefinite articles and figures such as "one", "two" etc. should generally be understood as "at least" information, i.e. as "at least one ...", "At least two ..." etc., unless it is explicitly stated in the respective context or it is obvious or technically imperative for a person skilled in the art that only "exactly one ...", "exactly two ..." etc. can be meant.

In one embodiment, the thermal insulation layer completely covers the inside of the heating mat. This ensures, among other things, that the heat from the heating mat cannot flow away, or only slightly, via the side of the heating roller facing away from the jacket tube, so that the heat generated by the heating mat can be supplied to the jacket tube as homogeneously as possible. If, on the other hand, certain areas of the heating mat were not covered by the thermal insulation layer, the heat flow there could lead to undesirably large temperature inhomogeneities on the outer surface of the heating roller.

In a further embodiment, the thermal insulation layer is permanently connected to the heating mat. This ensures, among other things, that the insulating effect of the thermal insulation layer on the heating mat is as homogeneous as possible for the entire heating mat. In addition, the assembly of the heating roller is also made easier because a common part can be installed instead of two independent parts.

In a further embodiment, the heat insulation layer is vulcanized onto the heating mat with its outside facing the heating mat. In this way, the thermal insulation layer is permanently connected to the heating mat in a particularly reliable manner, which leads to a long-lasting, homogeneous insulation effect of the thermal insulation layer on the heating mat.

In a further embodiment, the heat insulation layer is a foam layer, preferably a silicone foam layer. Such layers can be produced easily and with a flexible shape and provide a good insulating effect.

In one embodiment, the thermal insulation layer and the heating mat each have a thickness in the radial direction of the jacket tube, the thickness of the thermal insulation layer being at least the thickness of the heating mat, preferably up to a factor of 1.5 thicker than the heating mat, particularly preferably by more than one Factor 1.5 thicker than the thickness of the heating mat. For example, the heating mat can be 3 mm thick and the thermal insulation layer, for example a silicone foam layer, 5 mm thick. The heat insulation layer can also be 3 mm or 8 mm here.

In a further embodiment, the heating mat has a center along its thickness, with at least some of the heating wires in the heating mat being arranged beyond the center in the direction of the jacket tube. Among other things, this can improve the heat transfer from the heating mat to the jacket pipe. All heating wires are preferably laid beyond the middle in the heating mat. The heating wires can form a heating wire layer.

In a further embodiment, the spreading device has a cylindrical shape, preferably as a round bent sheet metal, and its outer side rests over the entire surface on the thermal insulation layer. As a result of this full-surface contact, a uniform pressure is exerted on the thermal insulation layer over the entire spreading device, so that the thermal contact between the heating mat and the jacket pipe to be heated is even more evened out.

In a further embodiment, one or more depressions are arranged on the outside of the spreading device at least partially circumferentially around the outside in an alignment perpendicular to the central axis of the casing tube. These depressions additionally stiffen the spreading device, which among other things further even out the contact pressure. Such spreading devices can then be provided with constant properties with a greater length. The recesses are preferably circumferential slots or beads in the outside of the spreading device. As corrugations are understood here channel-shaped depressions that serve to stiffen thin-walled components, here the spreading device, against deformation or vibration.

In a further embodiment, the spreading device comprises a first spreading device with a spreading effect against the thermal insulation layer in the radial spreading direction and a second spreading device with a spreading effect against the thermal insulation layer in the tangential spreading direction. By decoupling the spreading effect into a radial and a tangential spreading effect, the heating mat can be pressed in a more defined and significantly more uniform manner against the jacket tube of the heating roller. Here, the tangential and radial spread can be adapted more precisely to the conditions of the heating roller.

In a further embodiment, the first spreading device comprises a radial spreading means, which is arranged only along a single radial spreading direction between the opposite inner sides of the thermal insulation layer through a central axis of the circular cylindrical casing tube. Due to the spreading direction along only a single radial spreading direction, the effect of the simultaneously exerted tangential spreading extends over the entire half-shell of the spreading device. As a result, the tangential expansion can be exerted homogeneously on the entire area of the expansion device between the radial expansion means and thus on the entire area of the thermal insulation layer. If, instead, a radial spreading were exerted on the spreading device in an additional, second radial spreading direction (for example in the form of an arrangement of intersecting spokes), the tangential spreading effect could only be incomplete or possibly not at all in the area on the circumferential spreading device between the first and second radial spreading element are exercised, that is, in the area that lies, for example, between two support points of differently oriented support elements that are oriented to one another at an angle in the circumferential direction. Especially the arrangement with a first expansion element in a single radial expansion direction are very good Pressure ratios of the heating mat on the jacket tube of the heating roller reached.

In a further embodiment, the radial expansion means comprises one or more support elements which are each arranged parallel to the single radial expansion direction along a heating roller length. In this way, for example, slight unevenness of the jacket pipe can be compensated for. The distance between the end faces of the jacket pipe is referred to as the length of the heating roller.

In a further embodiment, the support elements are arranged in the form of tubes at equal distances from one another from one end face of the casing tube to the other end face of the casing tube. This enables the radial expansion effect to be made more uniform over the length of the heating roller.

In a further embodiment, the first expansion means is designed to be adjustable in length in the radial direction. Among other things, this facilitates the installation of the spreading device in the heating roller and enables an individual local adjustment of the radial spreading effect.

In a further embodiment, the second spreading device comprises a tangential spreading means, via which the spreading device rests on the inside of the thermal insulation layer in order to spread it in the tangential spreading direction. The expansion means makes it possible to set a tangential expansion effect in such a way that the most homogeneous pressure possible is exerted on the heating mat.

In a further embodiment, the tangential expansion means comprises two opposing support elements, preferably angular profiles, which are connected to one another with one or more mutual variable-distance connections, with the adjustment of which the opposing support elements can be moved towards or away from each other in the tangential expansion direction. This allows, among other things, the tangential spreading effect to be set precisely and very finely. In addition, such a second spreading device is easy to handle.

In a further embodiment, the spreading device is designed in such a way that the radial and tangential spreading effects can be set independently of one another. This is possible with the first and second spreading devices described above.

In a further embodiment, electrical connections of the at least one electrical heating mat between the tangential expansion means for the electrical supply of the heating mat are guided out of the thermal insulation layer or through it into an inner region of the jacket tube. From here, the electrical connections can be routed to and out of the axis of the jacket tube, for example via the first spreading device. The tangential expansion means offers a gap in the circumferential expansion device towards the inner volume of the jacket tube, which can be used for guiding the electrical connections. In a further embodiment, electrical connections of the heating mat are then continued through the spreading device in the direction of a power supplier for the heating mat.

In a further embodiment, two heating mats are arranged inside the jacket tube, each in the form of half cylinders on the inside of the jacket tube. Among other things, this makes it easy to assemble the heating mats and still cover the entire inner surface of the jacket pipe for the most homogeneous heating possible.

In a further embodiment, the jacket tube comprises at least one deep hole parallel to the outside of the jacket tube, in which one or more temperature sensors for determining a surface temperature are arranged on the outside of the jacket tube. With this arrangement, on the one hand, the surface temperature of the jacket pipe can be precisely determined and the heating power of the heating mat (s) can be controlled accordingly so that the desired surface temperature is reached or maintained. If there are several temperature sensors, it can be measured directly whether there is sufficient homogeneity of the surface temperature along the width of the heating roller. In other embodiments, several deep bores can also be present at different points on the casing tube.

In a further embodiment, only a single temperature sensor is arranged in the depth bore in the middle between the two end faces of the casing tube. The various configurations of the spreading device make it possible to achieve a homogeneity of the surface temperature, so that only a single temperature sensor is required to control the surface temperature.

In a further embodiment, the surface temperature of the outside of the casing tube varies over the surface by less than 5 ° C.

The invention further relates to a preheating cabinet for temperature control of a material web passed through the preheating cabinet, comprising at least one heating roller according to the invention. The material web is fed into the preheating cabinet via an entrance and then out of the preheating cabinet via an exit. Depending on the embodiment, the inlet and outlet of the preheating cabinet can be arranged on different sides, preferably opposite sides, of the preheating cabinet or on the same side of the preheating cabinet.

In one embodiment, the material web is heated to a temperature of 60-140 ° C. in the preheating cabinet with the at least one heating roller. The heating mat (s) of the heating roller (s) can be operated with 400V, for example, and have a heating power of 12000 W.

In a further embodiment, at least two of the heating rollers according to the invention are arranged in the preheating cabinet, with at least one first transport roller for feeding the material web to the heating rollers in front of the heating rollers and at least one second transport roller for leading the material web out of the preheating cabinet being arranged after the heating rollers, preferably the heating rollers and transport rollers are arranged in the preheating cabinet in such a way that the material web can be guided around the heating and transport rollers in an S-shape. The term “feeding the material web to the heating rollers” denotes the feeding of the material web to the first heating roller, via which the material web is then fed to the second heating roller. The first transport roller naturally also indirectly feeds the material web to the second heating roller.

Thus, a preheating cabinet, in particular for plastics processing machines, is made available, in which the heating rollers can be heated as homogeneously as possible and the heating means have a long service life.

The invention further relates to a system with a machine for material processing comprising a preheating cabinet according to the invention for tempering a material web for subsequent processing of the material web in the machine. Following the preheating cabinet, the machine can include one or more components for processing and further processing the material web or the products made from the material web.

In one embodiment, the material web comprises a composite material. In this case, however, the material web can also consist entirely of the composite material. For example, the material web is a plastic film.

In a further embodiment the machine is a thermoforming machine. With a thermoforming machine, thermoplastics can be formed under the influence of heat and with the help of compressed air and / or vacuum. Foils, usually with a smaller thickness, or plates, usually with a greater thickness, can be used as material webs.

Thus, a system, in particular with a plastics processing machine, is made available which includes a preheating cabinet in which the heating rollers for preheating the material web to be processed can be heated as homogeneously as possible and their heating means have a long service life.

• - Anordnen mindestens einer Heizmatte auf einer Innenseite eines kreiszylindrischen Mantelrohres der Heizwalze in Kontakt zum Mantelrohr;
• - Anordnen einer Wärmeisolationsschicht auf einer nicht dem Mantelrohr zugewandten Innenseite der Heizmatte;
• - Anordnen einer Spreizvorrichtung im Inneren des Mantelrohres auf einer Innenseite der Wärmeisolationsschicht; und
• - Ausüben einer Vorspannung über die Wärmeisolationsschicht auf die Heizmatte mittels der Spreizvorrichtung, sodass die dem Mantelrohr zugewandte Außenseite der mindestens einen Heizmatte dauerhaft gegen die Innenseite des Mantelrohres gedrückt wird.

The invention further relates to a method for producing a heating roller according to the invention for providing a desired surface temperature for controlling the temperature of a material web rotating around the heating roller, comprising the steps:

• - Arranging at least one heating mat on an inside of a circular cylindrical jacket tube of the heating roller in contact with the jacket tube;
• - Arranging a thermal insulation layer on an inside of the heating mat not facing the jacket tube;
• - Arranging a spreading device inside the jacket tube on an inside of the thermal insulation layer; and
• - Exerting a pretension via the thermal insulation layer on the heating mat by means of the spreading device, so that the outer side of the at least one heating mat facing the jacket pipe is pressed permanently against the inside of the jacket pipe.

In one embodiment, the steps of arranging the heating mat and the heat insulation layer are carried out together, since the heat insulation layer is permanently connected to the heating mat. This permanent bond can be implemented, for example, by means of vulcanization.

• - Ausübens einer Spreizwirkung gegen die Wärmeisolationsschicht in radialer Spreizrichtung mittels einer ersten Spreizeinrichtung der Spreizvorrichtung; und des
• - Ausübens einer Spreizwirkung gegen die Wärmeisolationsschicht in tangentialer Spreizrichtung mittels einer zweiten Spreizeinrichtung der Spreizvorrichtung.

In a further embodiment of the method, the step of exerting a prestress comprises the steps of

• Exerting a spreading effect against the thermal insulation layer in the radial spreading direction by means of a first spreading device of the spreading device; and des
• - Exerting a spreading effect against the thermal insulation layer in the tangential spreading direction by means of a second spreading device of the spreading device.

Thus, a method for producing the heating rollers according to the invention is provided so that the heating rollers are used to preheat the processed material web can be heated as homogeneously as possible and the heating means have a long service life.

It goes without saying that the above-described embodiments or features thereof can also be combined with one another in any combinations that differ from the claims and their references in order to provide solutions to the above object within the scope of the present invention.

Figure list

• 1 : heating roller according to the invention (a) in a perspective external view and (b) in a lateral section;
• 2 : an embodiment of the spreading device in the heating roller according to the invention (a) in a lateral section and (b) in an enlargement of the second spreading device;
• 3 : an embodiment of the spreading device with depressions on the outside in a perspective view;
• 4th : an embodiment of a preheating cabinet according to the invention;
• 5 : an embodiment of a system according to the invention;
• 6th : an embodiment of the heating roller according to the invention in a lateral section through the wall of the heating roller; and
• 7th : an embodiment of a method according to the invention for manufacturing the heating roller.

Detailed description of the figures

1 shows a heating roller according to the invention 1 (a) in a perspective external view and (b) in a lateral section to provide a desired surface temperature for controlling the temperature around the heating roller 1 circumferential material web 20th , the heating roller 1 a circular cylindrical jacket tube 2 made of thermally conductive material, preferably metal, and at least one electric heating mat 3 includes that on an inside 21 of the jacket pipe 2 in contact with the jacket pipe 2 is arranged. On one not the jacket pipe 2 facing inside 31 the heating mat 3 is a thermal insulation layer 4th arranged. Inside the jacket pipe 2 is a spreading device 5 on an inside 41 the thermal insulation layer 4th arranged that a bias so over the thermal insulation layer 4th on the heating mat 3 exercises so that one of the jacket pipe 2 facing outside 32 the at least one heating mat 3 permanently against the inside 21 of the jacket pipe 2 is pressed. The surfaces or sides that are the central axis MA of the jacket pipe 2 facing are here as inner pages 21 , 31 , 41 designated. The surfaces or sides that make up the outer surface 22nd of the jacket pipe 2 are facing are here as outsides 22nd , 32 , 42 , 5a designated. Here is the spreader 5 cylindrically shaped, preferably as a round bent sheet metal, and lies with its outside 5a over the entire surface of the thermal insulation layer 4th on. The spreader 5 comprises a first spreading device 51 with spreading effect against the thermal insulation layer 4th in the radial spreading direction RS and a second spreading device 52 with spreading effect against the thermal insulation layer 4th in the tangential expansion direction TS. For more details on the second spreader 52 is on the 2 and 3 referenced. For further details on the construction of the heating mat 3 is on the 6th referenced. On the heating roller shown here 1 the surface temperature of the outside varies 22nd of the jacket pipe 2 above the surface by less than 5 ° C. In order to be able to control the surface temperature, the jacket pipe encompasses 2 here also a single deep hole 23 parallel to the outside 22nd of the jacket pipe 2 , in which one or more temperature sensors 6th for determining a surface temperature on the outside 22nd of the jacket pipe 2 can be arranged, but in this embodiment only a single temperature sensor 6th in the middle between the two front sides 12a , 12b of the jacket pipe 2 .

The first spreader 51 comprises here a radial expansion means 51a , that only along a single radial spreading direction RS between the opposite inner sides 41 the thermal insulation layer 4th through the central axis MA of the circular cylindrical casing pipe 2 is arranged therethrough. The radial expansion means 51a here comprises four support elements, each parallel to the single radial spreading direction RS along a heating roller length 11 are arranged, the support elements 51a in the form of tubes with equal distances from one another from an end face 12a of the jacket pipe 2 to the other face 12b of the jacket pipe 2 are arranged to the radial spreading effect evenly over the heating roller length 11 to distribute. To do this is the first spreading agent 51a designed to be adjustable in length in the radial direction (length-adjustable tubes 51a) . Here is the spreader 5 designed so that the radial and tangential expansion effects can be set independently of one another.

There are also electrical connections 33 the at least one electric heating mat 3 between the tangential expansion means 52b for the electrical supply of the heating mat 3 from the thermal insulation layer 4th out or through them into an inner region of the jacket pipe 2 and towards an electricity supplier 34 the heating mat 3 continued.

2 shows an embodiment of the spreading device 5 of a heating roller according to the invention 1 (a) in a lateral section and (b) in an enlarged view of the second spreading device 52 . The second spreader 52 is shaped here as a round bent sheet metal with its outside 5a over the entire surface of the thermal insulation layer 4th should rest, here in the form of two half-shells as heating mats 3a , 3b with respective thermal insulation layers 4th , and includes a tangential expansion means 52b in order to spread them in the tangential spreading direction TS. The tangential expansion means 52b here comprises two opposing support elements 52c , preferably angle profiles with one or more mutual variable distance connections 52d are connected to each other, with the adjustment of the opposite support elements 52c can be moved towards one another or moved away from one another in the tangential spreading direction TS. There are also three recesses 53 on the outside 5a the spreading device 5 mostly all around the outside 5a in alignment perpendicular to the central axis MA of the jacket pipe 2 arranged, for further details see 3 .

3 shows an embodiment of the spreading device 5 with depressions 53 on the outside 5a in perspective view as it is in a heating roller 1 with heating mats already arranged in it 3a , 3b can be used. These depressions 53 are on the outside 5a the spreading device 5 than three wells 53 mostly all around the outside 5a in alignment perpendicular to the central axis MA of the jacket pipe 2 arranged. The depressions 53 are here as parallel slots or beads in the outside 5a the spreading device 5 introduced, for example embossed or made with a cutting or punching tool. The depressions 53 run here on the outside 5a not over the tangential expansion means 52b over, but end on both sides shortly before reaching the tangential expansion means 52b . This "gap" of the indentations 53 can be symmetrical on the opposite side of the cylindrical second spreader 52 to be available. Alternatively, where there is no tangential expansion means 52b is present, also be designed continuously. In the perspective view it can be clearly seen that the spreading device 5 is shaped here as a round bent sheet metal with its outside 5a over the entire surface of the thermal insulation layer 4th should rest.

4th shows an embodiment of a preheating cabinet according to the invention 10 for tempering one through the preheating cabinet 10 guided material web 20th comprising two heating rollers according to the invention 1 , being in front of the heating rollers 1 a first transport roller 30a for feeding the material web 20th to the first of the two heating rollers 1 and after the two heating rollers 1 a second transport roller 30b to divert the material web 20th from the preheating cabinet 10 are arranged out. Here are the heating rollers 1 and transport rollers 30a , 30b in the preheating cabinet 10 arranged so that the web of material 20th S-shaped around the heating and transport rollers 1 , 30a , 30b is shown around. The material web runs for this purpose 20th (not explicitly shown) from an inlet 40 of the preheating cabinet 10 first down around the first transport roller 30a around and on in an S-shape to the first of the two heating rollers 1 and around this and further down to the second of the two heating rollers 1 and around this and further in an S-shape to the second transport roller 30b and around it to the outlet of the preheater 10 where the preheated material web 20th from the preheating cabinet 10 exit. Here, the material web 20th in the preheating cabinet 10 with the two heating rollers 1 be warmed up to a temperature of 60 - 140 ° C. The exact temperature depends on the processing process and the material of the material web 20th set to the required preheating temperature.

5 shows an embodiment of a system according to the invention 100 with one machine 110 for material processing comprising a preheating cabinet according to the invention 10 (see also 4th ) for tempering a material web 20th for subsequent processing of the material web 20th in the machine 110 so that these end up after passing through other components 110a (for example a forming station and / or a cutting station and / or a stacking station, etc.) products 120 from the processed material web 20th can spend. These products 120 can represent end products for delivery to the customer or intermediate products for further processing or processing. The material web 20th can comprise a composite material or consist entirely of a composite material. For example, the material web 20th a plastic sheet. The material web 20th can be as running material from a roll or piece by piece, for example in the form of plates, of the machine 110 are fed. The machine 110 is for example a thermoforming machine.

6th shows an embodiment of the heating roller according to the invention 1 in a lateral section through the wall of the heating roller 1 , taking an electric heating mat 3 on an inside 21 of the jacket pipe 2 in contact with the jacket pipe 2 is arranged. Not on the jacket pipe 2 facing inside 31 the heating mat 3 is again a thermal insulation layer 4th arranged. A spreading device then follows in the layer structure 5 on an inside 41 the thermal insulation layer 4th arranged. This spreader 5 should be a bias so over the thermal insulation layer 4th on the heating mat 3 exercise that the the jacket pipe 2 facing outside 32 the heating mat 3 durable and as homogeneous as possible against the inside 21 of the jacket pipe 2 is pressed. It is advantageous if, as shown, the thermal insulation layer 4th the inside 31 the heating mat 3 completely covered. This can be done by the thermal insulation layer 4th permanently with the heating mat 3 be connected. For example, the thermal insulation layer 4th with her the heating mat 3 facing outside 42 on the heating mat 3 vulcanized. The thermal insulation layer 4th can be designed as a foam layer, preferably as a silicone foam layer. Such layers provide good thermal insulation from the inside 41 ready. It is therefore irrelevant for the thermal insulation which material the spreading device is made of 5 is made. The thermal insulation layer 4th and the heating mat 3 each have a thickness 3d , 4d in the radial direction of the casing pipe 2 , with the thickness 4d the thermal insulation layer 4th at least the thickness 3d the heating mat 3 can be, preferably up to a factor of 1.5 thicker than the heating mat 3 may be, particularly preferably more than a factor of 1.5 thicker than the thickness 3d the heating mat 3 can be. The heating mat 3 possesses along its thickness 3d a middle 3m , with all the heating wires here 35 (shown here as a layer for the sake of simplicity) of the heating mat 3 beyond the middle 3m in the direction of the jacket pipe 2 are arranged, which improves the heat transfer to the jacket tube 2 contributes. The layer structure of the heating mat 3 can be designed as follows: for the thermal insulation layer 4th there is a top layer 36 arranged, including a silicone layer 37 , the heating wires here in the form of a heating wire layer 35 and another top layer 36 to the inside 21 of the jacket pipe 2 down. The electrical connections 33 the heating mat 3 lead from the heating mat 3 for example between the tangential expansion means 52b for the electrical supply of the heating mat 3 from the thermal insulation layer 4th out or through them into an inner region of the jacket pipe 2 and from the heating roller 1 , for example via the axle suspension.

7th shows an embodiment of a method according to the invention 200 for producing the heating roller according to the invention 1 to provide a desired surface temperature for controlling the temperature around the heating roller 1 circumferential material web 20th comprising the steps of arranging 210 at least one heating mat 3 on an inside 21 a circular cylindrical jacket pipe 2 the heating roller 1 in contact with the jacket pipe 2 and arranging 220 a thermal insulation layer 4th on one not the jacket pipe 2 facing inside 31 the heating mat 3 . Here you can use the heating mat 3 and the thermal insulation layer 4th be arranged in succession or in a common step in the jacket tube. The method further comprises the steps of arranging 230 a spreader 5 inside the jacket pipe 2 on an inside 41 the thermal insulation layer 4th and exercising 240 a bias over the thermal insulation layer 4th on the heating mat 3 by means of the spreading device 5 so that the jacket pipe 2 facing outside 32 the at least one heating mat 3 permanently against the inside 21 of the jacket pipe 2 is pressed. Here you can use the steps of arranging 210 , 220 the heating mat 3 and the thermal insulation layer 4th be carried out together by the thermal insulation layer 4th permanently with the heating mat 3 , preferably by means of vulcanization. The step of exercising 240 A preload can include the steps of exercising 242 a spreading effect against the thermal insulation layer 4th in the radial spreading direction RS by means of a first spreading device 51 the spreading device 5 and exercising 244 a spreading effect against the thermal insulation layer 4th in the tangential spreading direction TS by means of a second spreading device 52 the spreading device 5 include. The radial and tangential spreading effects can be set either one after the other or simultaneously with one another or alternately piece by piece in an iterative process until the desired spreading effect of the spreading device is achieved 5 is set or the heating mat 3 completely homogeneous on the inside 21 of the jacket pipe 2 is applied.

At this point, it should be explicitly pointed out that features of the solutions described above or in the claims and / or figures can optionally also be combined in order to also be able to implement or achieve cumulatively explained features, effects and advantages.

It goes without saying that the exemplary embodiment explained above is only a first embodiment of the present invention. In this respect, the configuration of the invention is not limited to these exemplary embodiments above.

Claims (32)

A heating roller (1) for providing a desired surface temperature for controlling the temperature of a material web (20) rotating around the heating roller (1), the heating roller (1) being a circular cylindrical jacket tube (2) made of a thermally conductive material, preferably metal, and at least one electrical heating mat ( 3), which is arranged on an inside (21) of the jacket tube (2) in contact with the jacket tube (2), with a heat insulation layer (4) on an inside (31) of the heating mat (3) not facing the jacket tube (2) ) is arranged and inside the jacket tube (2) a spreading device (5) on an inside (41) of the Thermal insulation layer (4) is arranged, which exerts a pre-tension on the heating mat (3) via the thermal insulation layer (4) so that an outer side (32) of the at least one heating mat (3) facing the jacket tube (2) permanently against the inner side (21 ) of the jacket pipe (2) is pressed. The heating roller (1) after Claim 1 , characterized in that the thermal insulation layer (4) completely covers the inside (31) of the heating mat (3). The heating roller (1) after Claim 1 or 2 , characterized in that the thermal insulation layer (4) is permanently connected to the heating mat (3). The heating roller (1) after Claim 3 , characterized in that the heat insulation layer (4) with its outer side (42) facing the heating mat (3) is vulcanized onto the heating mat (3). The heating roller (1) according to one of the preceding claims, characterized in that the heat insulation layer (4) is a foam layer, preferably a silicone foam layer. The heating roller (1) according to one of the preceding claims, characterized in that the thermal insulation layer (4) and the heating mat (3) each have a thickness (3d, 4d) in the radial direction of the casing tube (2), the thickness (4d) the thermal insulation layer (4) is at least the thickness (3d) of the heating mat (3), preferably up to a factor of 1.5 thicker than the heating mat (3), particularly preferably more than a factor of 1.5 thicker than the thickness ( 3d) the heating mat (3) is. The heating roller (1) according to one of the preceding claims, characterized in that the heating mat (3) has a center (3m) along its thickness (3d), at least some of the heating wires (35) in the heating mat (3) beyond the Center (3m) are arranged in the direction of the jacket pipe (2). The heating roller (1) according to one of the preceding claims, characterized in that the spreading device (5) is cylindrical in shape, preferably as a curved sheet metal, and rests with its outer side (5a) over the entire surface of the thermal insulation layer (4). The heating roller (1) after Claim 8 , characterized in that on the outside (5a) of the spreading device (5) one or more depressions (53) are arranged at least partially circumferentially around the outside (5a) in alignment perpendicular to the central axis (MA) of the casing tube (2), preferably are the recesses (53) encircling slots or beads in the outside (5a) of the spreading device (5). The heating roller (1) according to one of the preceding claims, characterized in that the spreading device (5) has a first spreading device (51) with spreading effect against the thermal insulation layer (4) in the radial spreading direction (RS) and a second spreading device (52) with spreading effect against the thermal insulation layer (4) comprises in the tangential spreading direction (TS). The heating roller (1) after Claim 10 , characterized in that the first expansion device (51) comprises a radial expansion means (51a) which only extends along a single radial expansion direction (RS) between the opposite inner sides (41) of the thermal insulation layer (4) through a central axis (MA) of the circular cylindrical jacket tube (2) is arranged therethrough. The heating roller (1) after Claim 11 , characterized in that the radial expansion means (51a) comprises one or more support elements which are each arranged parallel to the single radial expansion direction (RS) along a heating roller length (11). The heating roller (1) after Claim 12 , characterized in that the support elements (51a) are arranged in the form of tubes at equal distances from one another from one end face (12a) of the casing tube (2) to the other end face (12b) of the casing tube (2). The heating roller (1) after one of the Claims 10 to 13th , characterized in that the first expansion means (51a) is designed to be adjustable in length in the radial direction. The heating roller (1) after one of the Claims 10 to 14th , characterized in that the second spreading device (52) comprises a tangential spreading means (52b) via which the spreading device (5) rests on the inside (41) of the thermal insulation layer (4) in order to spread it in the tangential spreading direction (TS). The heating roller (1) after Claim 14 or 15th , characterized in that the tangential expansion means (52b) comprises two opposing support elements (52c), preferably angle profiles, which are connected to one another with one or more mutually variable distance connections (52d), with the adjustment of which the opposing support elements (52c) in the tangential expansion direction ( TS) can be moved towards or away from each other. The heating roller (1) after one of the Claims 10 to 16 , characterized in that the spreading device (5) is designed so that the radial and tangential spreading effects can be set independently of one another. The heating roller (1) after one of the Claims 14 to 17th , characterized in that electrical connections (33) of the at least one electrical heating mat (3) between the tangential expansion means (52b) for the electrical supply of the heating mat (3) out of the thermal insulation layer (4) or through it into an inner region of the jacket pipe (2) are performed. The heating roller (1) after one of the Claims 18 , characterized in that electrical connections (33) of the heating mat (3) are continued through the spreading device (5) in the direction of a power supply (34) of the heating mat (3). The heating roller (1) according to one of the preceding claims, characterized in that two heating mats (3) each in the form of half-cylinders (3a, 3b) are arranged on the inside (21) of the jacket tube (2) within the jacket tube (2). The heating roller (1) according to one of the preceding claims, characterized in that the casing tube (2) comprises at least one deep bore (23) parallel to the outside (22) of the casing tube (2), in which one or more temperature sensors (6) for determination a surface temperature on the outside (22) of the jacket tube (2) are arranged. The heating roller (1) after Claim 21 , characterized in that only a single temperature sensor (6) is arranged in the depth bore (23) in the middle between the two end faces (12a, 12b) of the casing tube (2). The heating roller (1) according to one of the preceding claims, characterized in that the surface temperature of the outside (22) of the casing tube (2) varies by less than 5 ° C over the surface. A preheating cabinet (10) for tempering a material web (20) passed through the preheating cabinet (10), comprising at least one heating roller (1) according to one of the preceding claims. The preheating cabinet (10) after Claim 24 , characterized in that the material web (20) is heated in the preheating cabinet (10) with the at least one heating roller (1) to a temperature of 60-140 ° C. The preheating cabinet (10) after Claim 24 or 25th , characterized in that at least two of the heating rollers (1) are arranged in the preheating cabinet (10), with at least one first transport roller (30a) in front of the heating rollers (1) for feeding the material web (20) to the heating rollers (1) and after the Heating rollers (1) at least one second transport roller (30b) for guiding the material web (20) out of the preheating cabinet (10) are arranged, preferably the heating rollers (1) and transport rollers (30a, 30b) are arranged in the preheating cabinet (10) in such a way that that the material web (20) can be guided around the heating and transport rollers (1, 30a, 30b) in an S-shape. A system (100) comprising a machine (110) for material processing and a preheating cabinet (10) according to one of the Claims 24 to 26th for tempering a material web (20) for subsequent processing of the material web (20) in the machine (110). The plant (100) according to Claim 27 , characterized in that the material web (20) comprises a composite material, preferably consists of a composite material, particularly preferably a plastic film. The plant (100) according to Claim 27 or 28 , characterized in that the machine (110) is a thermoforming machine. A method (200) for manufacturing a heating roller (1) according to one of the Claims 1 to 23 to provide a desired surface temperature for controlling the temperature of a material web (20) circulating around the heating roller (1), comprising the steps of: - arranging (210) at least one heating mat (3) on an inside (21) of a circular cylindrical jacket tube (2) of the heating roller (1) ) in contact with the jacket tube (2); - Arranging (220) a thermal insulation layer (4) on an inside (31) of the heating mat (3) not facing the jacket tube (2); - Arranging (230) a spreading device (5) inside the jacket tube (2) on an inside (41) of the thermal insulation layer (4); and - exerting (240) a pretension over the thermal insulation layer (4) on the heating mat (3) by means of the spreading device (5) so that the outer side (32) of the at least one heating mat (3) facing the jacket tube (2) is permanently against the inner side (21) of the jacket pipe (2) is pressed. The method (200) according to Claim 30 , wherein the steps of arranging (210, 220) the heating mat (3) and the thermal insulation layer (4) are carried out together, since the thermal insulation layer (4) is permanently connected to the heating mat (3), preferably by means of vulcanization. The method (200) according to Claim 30 or 31 wherein the step of exerting (240) a pretensioning comprises the steps of - exerting (242) a spreading effect against the thermal insulation layer (4) in the radial spreading direction (RS) by means of a first spreading device (51) of the spreading device (5); and - exerting (244) a spreading effect against the thermal insulation layer (4) in the tangential spreading direction (TS) by means of a second spreading device (52) of the spreading device (5).

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