Heating unit comprising a cover element

Abstract

The present invention relates to a heating unit for heating or warming up the packaging material, in particular a plastic monofilm, in a packaging machine. The present invention also relates to a packaging machine.

Description

[0001] Heating element with a cover element

[0002] The present invention relates to a heating element for heating or warming the packaging material, in particular a monoplastic film, in a packaging machine. Furthermore, the present invention relates to a packaging machine.

[0003] Heating elements are known from the prior art, for example from WO2022002968, WO2023078919 or WO 2023078797, and are part of a packaging machine. In these packaging machines, a trough is formed into a flat material web, for example a film web, by deep drawing. For this purpose, the material web must be heated with a heating element before deep drawing. Particularly with monofilms consisting of a single material, heating must be rapid and uniform; a minimum permissible temperature for the desired forming result must not be undercut and a maximum permissible temperature must not be exceeded, whereby the difference between the minimum and maximum permissible temperature is very small, i.e. there is only a small temperature window. At the same time, heating must take place quickly in order to be able to provide sufficient cycle power.Nowadays, very high demands are also placed on the availability of a heating element in order to optimize the production times of the packaging machine.

[0004] It was therefore the object of the present invention to provide a heating element and a packaging machine and a method for cleaning the heating element which do not have the disadvantages of the prior art.

[0005] The object is achieved by a heating element for heating the packaging material, in particular a monoplastic film, in a packaging machine with at least one, preferably several heating means and with a thermal insulation and / or a carrier plate and a cover element, wherein a connecting element (19) is provided between the cover element and the thermal insulation and / or the carrier plate and the connecting element has a bolt which is frictionally connected to the cover element.

[0006] The statements made regarding this subject matter of the present invention apply equally to the other subjects, and vice versa. Features of this subject matter of the present invention can be incorporated into other subjects, and vice versa.

[0007] The present invention relates to a heating element that is used to heat a material web, in particular in a packaging machine. Preferably, the heating element is a plate, but not necessarily, but preferably, such a flat, two-dimensional object. However, it can also be curved or have another three-dimensional shape. The heating element is preferably located upstream of a forming tool, relative to the transport direction of the material web, for example as a so-called preheater. Alternatively or additionally, the heating element is integrated into the forming tool, for example as a so-called lid heater. The heating element can be directly connected to a carrier that is part of the packaging machine, in particular part of the forming station and here in particular part of the upper tool, or it can be an integral part of the carrier.This carrier and / or the heating element can be provided for vertical movement, allowing it to be moved toward and away from the material web. Alternatively or additionally, the heating element is located upstream of a sealing tool of the sealing station, relative to the transport direction of the material web, and / or is integrated into the sealing tool.

[0008] Preferably, the packaging material is sucked onto the heating element for heating by means of negative pressure in order to improve the heat transfer between the heating element and the packaging material.

[0009] The heating element, which is usually operated with electrical energy, heats the material web preferably from one side, for example from above as in a cover heating system or from below as in a so-called "preheating from below", or from both sides, for example from above and below, as in a sandwich heating system as a so-called "preheating from above and below", especially if the energy input into the material web is to be even faster.

[0010] Each heating element has at least one, preferably a plurality of heating means.

[0011] For this purpose, the heating element can have several, in particular discrete, heating means, for example 5 - 50, preferably 51 - 100, even more preferably 101 - >1000 heating means. Such heating means are, for example, one or more circuit boards or conductor foils, for example heating foils, which can each be supplied with electrical energy differently in order to achieve different actual temperatures in the segments and / or can be regulated / controlled with different actual and / or setpoint values. The heating means can be provided according to a specific pattern. Preferably, they are not provided equidistantly. The heating means of a heating element can differ from one another in shape and / or size and / or heating output. The heating means can also consist of a plurality of pixels that can be controlled individually and / or in groups. These pixels can be arranged in a specific pattern in a segment and / or in the heating element.The pixels are preferably distributed equidistantly across the heating element. Preferably, a specific number of pixels are arranged on a circuit board, and the heating element may comprise a plurality of such circuit boards. The pixels of a circuit board can be controlled individually or in one or more groups.

[0012] Alternatively or additionally, the heating means comprises one or more conductor tracks. The heating means preferably consists of a plurality of segments, each of which comprises one or more conductor tracks, wherein the conductor tracks of each segment and the segments themselves can preferably be individually controlled and / or heated with electrical energy.

[0013] Preferably, the heating means has recesses by means of which a negative pressure can be created between the material web and the covering element. The recesses are preferably arranged in a pattern, in particular in a repeating pattern.

[0014] The heating element preferably has thermal insulation, which is particularly preferably in direct contact with the heating medium and, if necessary, supports it. In particular, the thermal insulation serves to minimize the uncontrolled and / or unwanted outflow of thermal energy into the environment, so that the thermal energy provided by the heating element is made available to the web of material or transferred to it with little loss and as completely as possible. The thermal insulation consists, for example, of a plastic material, in particular a foamed plastic material. According to the invention, the thermal insulation is not provided as a single element, but is segmented, for example in order to be able to compensate for the effects of deformations due to thermal expansion and / or to minimize thermal stresses, for example due to uneven temperature distribution. These segments are preferably separated from one another by a gap.Preferably, all segments of a thermal insulation are the same size. Preferably, the heating element has a carrier plate that mounts and / or supports the segments of the thermal insulation. Preferably, the carrier plate has means that fix the thermal insulation and / or heating means in their position relative to the carrier plate. For example, the means are guide frames and / or fastening means such as screws. The mounting and / or support is shear-resistant or, alternatively, is preferably provided as a floating mounting, which, for example, allows for the compensation of different thermal expansions in particular. This carrier plate is made of metal, in particular aluminum or plastic, for example. The carrier plate can be printed, for example.

[0015] According to the invention, a cover element is provided on the side of the heating element facing the material web, for example, a protective plate only a few tenths of a millimeter thick, in particular a 0.2-2 mm thick, protective plate, in particular to protect a heating medium provided as a heating foil from mechanical damage or from dirty water. The cover element is preferably made of a material with good thermal conductivity, in particular metal, preferably aluminum or stainless steel. Preferably, there is direct and preferably full-surface contact between the heating medium and the cover element.

[0016] According to the invention, the cover element now has a bolt that is frictionally connected to the cover element. In particular, the bolt is a press-in bolt. It has been shown that only frictionally engaged connections, such as a press-in bolt, result in a permanent connection that can withstand the constant load changes caused by vacuum drawing. Press-in bolts also do not negatively affect the appearance of the resulting packaging, i.e., they leave no or only minimal marks in the packaging material.

[0017] For example, the bolt on the cover element is provided as a threaded pin(s) or sleeve(s) which engages with a complementary threaded element provided on the thermal insulation and / or the support plate and clamps the cover element to the thermal insulation and / or the support plate and thereby, for example, improves the contact between the cover element and the heating means.

[0018] The cover element preferably has recesses by means of which a negative pressure can be created between the material web and the cover element. The recesses are preferably arranged in a pattern, in particular in a repeating pattern. In addition, the cover element can have a film or coating which preferably has a non-stick effect on the material web to be heated, in particular to promote slight local migration of the material web on the heating element to compensate for / smooth out wrinkles or to prevent or minimize disruptive adhesion of the fully heated material web during detachment from the heating element, which can be helpful, for example, with material webs that consist predominantly of A-PET and / or A-PET recyclate, in order to prevent or minimize undesired deformations or wrinkles on the material web and wear on the heating element or the cover element.

[0019] Preferably, the carrier plate has at least one vacuum channel that can be connected to a vacuum source to create a negative pressure between the heating element and the material web.

[0020] The carrier plate preferably has at least one vacuum distribution chamber per segment. Each chamber is preferably provided at least partially congruent with the recesses of a segment, so that all recesses of a segment can be subjected to negative pressure simultaneously.

[0021] According to a preferred embodiment, the heating element, in particular the cover element, has a centering means with which the recesses in the cover element, the heating means, and the thermal insulation can be aligned. This centering means is, for example, one or more pins and / or fitting screws that engage in corresponding recesses in the heating means and / or the thermal insulation. Particularly preferably, the centering means are one or more bolts.

[0022] The material web is preferably a monoplastic film or monofilm, i.e. a plastic film which consists of at least one layer and / or a single material or predominantly of a single material, for example at least 95% by weight of one material and / or a mixture of substances from a material group and is preferably considered to be reusable and / or moderately or highly recyclable; in contrast to multilayer films or films which consist of a mixture of substances from different material groups which are considered to be not or at most lowly recyclable. The material of the monofilm is preferably 100% by weight or predominantly, in particular at least 95% by weight, polypropylene (PP), polyethylene (PE) or polyethylene terephthalate (PET) or a mixture of substances from just one material group, for example polyolefins, for example PP and PE. For example, a monofilm can consist of at least 95% by weight.-% consist of at least one PP layer bonded to a sealing or peel layer made of PE.

[0023] The thickness of the monofilm is preferably 250-500 pm, particularly preferably 290-310 pm. The temperature window is preferably 135-137 °C, or the temperature window covers a range of preferably 3 Kelvin.

[0024] Preferably, with a thickness of the monofilm of 250 - 500 pm, 2.5 - 5 seconds are required, or with a higher energy input even only 1 - 3 seconds, to bring the material web to the desired temperature at which deep drawing with a deep drawing result, for example good shaping, is possible.

[0025] A further inventive or preferred subject matter of the present invention is a heating element having a seal provided between the cover element and the thermal insulation and / or between the cover element and the carrier plate.

[0026] The statements made regarding this subject matter of the present invention apply equally to the other subjects, and vice versa. Features of this subject matter of the present invention can be incorporated into other subjects, and vice versa.

[0027] The present invention relates to a heating element in which a seal is provided between the cover element and the thermal insulation and / or between the cover element and the support plate. This seal prevents, in particular, a liquid, for example a cleaning liquid and / or steam, from reaching the heating medium. The seal is preferably a circumferential seal, which preferably extends circumferentially along the inside of the cover element. For example, the seal is an O-ring. The seal is preferably endless.

[0028] Preferably, the cover element is provided as a plate with a circumferential edge, with the packaging material in particular resting against the plate. The plate can have recesses through which a vacuum is drawn to improve contact between the plate and the packaging material to be heated. Preferably, the seal between the edge and the insulation and / or the carrier plate is provided, in particular circumferentially, along a closed circle.Another inventive or preferred subject of the present invention is a heating element for heating the packaging material, in particular a monoplastic film, in a packaging machine with a plurality of heating means, wherein a transport means transports the packaging material intermittently by a specific, selectable format length along the packaging machine and a control which activates the heating elements according to the selected format length, in particular with electrical energy, and / or heats them.

[0029] The statements made regarding this subject matter of the present invention apply equally to the other subjects, and vice versa. Features of this subject matter of the present invention can be incorporated into other subjects, and vice versa.

[0030] The subject matter of the present invention relates to a heating element for a packaging machine that can be operated with different format lengths along the transport direction of the packaging machine, so that different lengths of packaging material must be heated. This subject matter of the present invention takes this into account in that the heating element has several heating means that are controlled by a controller according to the respective format length.

[0031] Preferably, the heating means that are not activated by the control system are provided with a cooling capability. This cooling can be achieved directly or indirectly. Preferably, the heating means is in contact with insulation, which is then cooled.

[0032] A further preferred or inventive subject matter of the present invention is a heating element (20) in which a space between the cover element and the heating means and / or the thermal insulation is provided so as to be connectable to an overpressure source.

[0033] The statements made regarding this subject matter of the present invention apply equally to the other subjects, and vice versa. Features of this subject matter of the present invention can be incorporated into other subjects, and vice versa.

[0034] In this aspect of the present invention, a space provided between the cover element and the heating means and / or the thermal insulation can be connected to an overpressure source, in particular an air pressure source. This occurs, for example, during cleaning of the heating element and / or the packaging machine. Due to the overpressure, no cleaning agent can enter this space and, for example, damage the heating means.

[0035] The cover element preferably has recesses through which the packaging material can be sucked onto the heating element. If the space between the cover element and the heating medium and / or the thermal insulation is subjected to air pressure, air preferably flows through these recesses, preventing liquid from penetrating these recesses or even being blown out again.

[0036] The object is also achieved with a packaging machine having a forming station, a filling station, a sealing station and a longitudinal and / or transverse cutter, wherein a material web can be transported along a running direction, in particular in cycles, and which has a heating element according to the invention or a preferred heating element according to the present invention.

[0037] The statements made regarding this subject matter of the present invention apply equally to the other subjects, and vice versa. Features of this subject matter of the present invention can be incorporated into other subjects, and vice versa.

[0038] The subject matter of the present invention relates to a packaging machine for producing packaging, in which a base material web, for example a plastic film or a material web which in particular has a cardboard, paper or another layer other than plastic, is unrolled from a supply roll and preferably transported intermittently / cyclically along the packaging machine in a transport plane. In a forming station, this base film web is then first formed using a thermoforming tool in order to form, for example, a trough and / or a structure, in particular an anti-slip structure, into the base material web. The forming station generally has a lower and an upper tool, which are moved towards one another for forming and away from one another for further transport of the base material web. The lower tool is located below and the upper tool above the transport plane of the base material web.As a rule, several packages arranged in a so-called format are processed simultaneously in the packaging machine according to the invention and subsequently transported simultaneously along the packaging machine. Before and / or during thermoforming, the base material web is heated with a heating element. The base material web is then covered with a packaged product, in particular a food product such as sausage, ham or cheese, or alternatively, for example, non-food packaged goods such as medical devices or other products, and in a next step, it is sealed with a top film in a sealing station, whereby the top film is usually sealed to the bottom film web. For this purpose, an additional heating element is used to provide the heat energy required for sealing.The finished packaging is then separated by cutting it out of the bottom and top material webs, for example using a cross cutter and a longitudinal cutter. The cross cutter or longitudinal cutter can also be provided as a contour punch. The top material web is also unwound from a supply roll and can also be deep-drawn, for example in a top film forming station, after it has preferably been heated with the heating element according to the invention. With respect to the transport direction of the respective film web, a dancer is preferably located downstream of at least one supply roll, which keeps the tension in the respective material web at least substantially constant. The dancer can be, for example, a linear or a rotary dancer.

[0039] Preferably, the heating element that heats the material web to be deep-drawn is located upstream of the forming tool(s) of the forming station. The heating element can be firmly connected to one tool, for example, the upper tool, and / or its frame, and can, for example, be moved vertically together with it.

[0040] Preferably, the distance between the forming tool and the upstream heating element is as small as possible, preferably a few millimeters, preferably 0.5 to 1 mm, firstly to save installation space and material web, and secondly to reduce or even minimize cooling of the material web before forming, but especially to be able to heat the material web in the directly upstream adjacent format area. Preferably, a segment whose longitudinal extension runs parallel to the transverse extension of the heating element is provided directly adjacent to the forming station.

[0041] Another subject of the present invention is a method for cleaning a heating element for heating the packaging material, in particular a monoplastic film, in a packaging machine with at least one, preferably several heating means and with thermal insulation and / or a carrier plate and a cover element, in which method an overpressure is generated between the cover element and the heating means, the thermal insulation and / or the carrier plate before and / or during and / or after the heating element is exposed to a cleaning fluid. The invention is explained below with reference to Figures 1 to 6. These explanations are merely examples and do not limit the general inventive concept.

[0042] The statements made regarding this subject matter of the present invention apply equally to the other subjects, and vice versa. Features of this subject matter of the present invention can be incorporated into other subjects, and vice versa.

[0043] Figure 1 shows schematically the packaging machine according to the invention.

[0044] Figures 2 - 8 show an embodiment of the heating element according to the invention

[0045] Figure 1 shows the packaging machine 1 according to the invention, which has a forming station 2, a filling station 7, and a sealing station 15. The packaging machine can be a so-called thermoformer. A base material web 8, here a plastic film 8, in particular a monofilm made of PP, PE, or PET, is drawn from a supply roll and transported in cycles along the packaging machine according to the invention from right to left. In each cycle, the base material web 8 is transported further by one format length / feed length. For this purpose, the packaging machine has two transport means, in this case two endless chains each, which are arranged to the right and left of the base material web 8. Both at the beginning and at the end of the packaging machine, at least one gearwheel is provided for each chain, around which the respective chain is deflected. At least one of these gearwheels is driven.The gears in the inlet area and / or in the outlet area can be connected to one another, preferably by a rigid shaft. Each transport means has a plurality of clamping means / grippers that clamp the base material web 8 in the inlet area and transfer the movement of the transport means to the base material web 8. In the outlet area of ​​the packaging machine, the clamping connection between the transport means and the base material web 8 is released again. Downstream of the inlet area and upstream of the forming station 2, a heating element 20 is provided, which heats the base material web 8, particularly when it is stationary. The forming station 2 has a lower tool 4 and an upper tool 3. The lower tool 4 can be moved up and down, as indicated by the double arrow, whereby it is moved upwards towards the base material web 8 for forming and downwards for further transport of the base material web 8.In the raised position, the lower material web is preferably clamped between the two tools 3, 4. The lower tool 4 can be arranged on a lifting table 5, which, as symbolized by the double arrow, can be vertically adjustable in order to generate the movement of the lower tool described above. As the packaging machine continues, the packaging troughs 6 indicated here, which are formed into the lower material web, are then filled with the packaging item 16 in the filling station 7. In the subsequent sealing station 15, which also consists of an upper tool 12 and a lower tool 11, which can be vertically adjustable if necessary, an upper film 14 is firmly attached to the lower material web 8 by sealing. As a result, the movement of the lower material web 8 is transferred to the upper material web 14. In the sealing station, the upper tool and / or optionally the lower tool are also lowered or raised before and after each film transport.raised. The upper film 14 can also be guided in transport means or transported by transport chains, whereby these transport means then only extend in front of the sealing station and possibly upstream. Otherwise, the comments made regarding the transport means for the lower film apply. The upper film can also be heated with a heating element and / or deep-drawn. For sealing, a sealing frame, for example, is provided as the lower tool 11, which has an opening for each packaging tray into which the packaging tray, if present, dips during sealing, i.e. during the upward movement of the lower sealing tool. For sealing, the upper and lower material webs are pressed together between the upper and lower tools 12, 11 and bond under the influence of heat and pressure. After sealing, the tools 11, 12 are moved apart vertically again.A dancer, for example a rotary dancer, can be provided between the supply roll of the upper material web 14 and the sealing tool, which holds the material web 14 at as constant a tension as possible. Those skilled in the art will understand that a dancer can also preferably be provided in the region of the lower material web 8, preferably downstream of the supply roll. The dancer is preferably a linear dancer. Before and / or during sealing of the upper material web to the lower material web, a gas exchange preferably takes place in each packaging tray. For this purpose, the air present in the packaging tray is first partially sucked out and / or replaced with a replacement gas. For this purpose, holes can be made in the lower material web 8 in the area of ​​the transport chains in the area of ​​each format, through which the air between the material webs 8, 14 is sucked out and / or the replacement gas is blown in.Further along the packaging machine, the finished packages are separated, which is done, for example, with the cross cutter 18 and the longitudinal cutter 17. In the present case, the cross cutter 18 can also be raised or lowered using a lifting device 9. According to another embodiment, the sealing tool 11, 12 has a punch that cuts the bottom and top material webs before, during and / or after sealing. Preferably, several packages are produced simultaneously in each cycle and are arranged in a so-called format as a matrix. Preferably, the heating element 20 has means with which the contact between the material web and the surface of the heating element can be established or improved. Such means are, for example, vacuum nozzles that suck the material web towards the surface of the heating element.

[0046] Figures 2-8 show embodiments of the heating element 20 according to the invention. This element comprises a support plate 22 on which thermal insulation 19 is arranged. The thermal insulation is made, for example, of a foamed plastic.

[0047] According to the invention, this thermal insulation consists of a plurality of segments 19a, b, in the present example 9 segments. The number of segments depends on the size of the format and / or the material of the thermal insulation. An air gap is preferably provided between the segments. The segments are attached to the support lath, preferably in such a way that the gap between the segments has as constant a width as possible. Each segment has two opposing surfaces, with one surface, here the lower one, facing the support plate 22. A heating means (not shown) rests on the other surface, here the upper one. The heating means can be a solid component or a film. The heating means can be provided in one piece or in segments.

[0048] On the side of the heating element facing the material web to be heated, the heating element preferably has a cover element 32 (see Figures 5, 8), preferably made of a material with good thermal conductivity, in particular metal, preferably aluminum or stainless steel, which at least partially covers and thus protects the heating means and preferably the thermal insulation. The material web to be heated preferably lies against the heating element, in particular the cover element, over its entire surface. Preferably, there is contact between the heating means(s) and the cover element 32 over as full a surface as possible, so that heat transfer can occur as far as possible by thermal conduction.

[0049] As can be seen particularly in Figures 5 and 8, the cover element 32 preferably comprises a plate that is in contact with the material web for heating purposes and a peripheral edge that is preferably beveled. The peripheral edge preferably covers at least the thermal insulation and particularly preferably extends to the carrier plate.

[0050] To improve the contact between the material web 8, 14 and the heating element 20, in particular its cover element 32, the cover element has recesses through which air can be sucked out, creating a vacuum that draws the material web toward the heating element 20. Preferably, the heating means and / or each segment also have recesses 23 in which a vacuum can be created. The recesses are preferably arranged in a grid. Preferably, the grid is identical in the cover element, in the heating means, and / or in the thermal insulation, and / or the recesses in the cover element, in the heating means, and / or in the thermal insulation are at least partially aligned.

[0051] Preferably, gas exchange should not occur between the segments 19a, b. For this purpose, a seal can be provided between the thermal insulation 19 and the carrier 22 and / or between the thermal insulation 19 and the heating means and / or the cover element. Each segment preferably has at least one seal on one or both of the opposing surfaces. The seal preferably extends along the circumference of the segment, in particular along one or both of the opposing surfaces. The thermal insulation and / or the carrier plate preferably have form-fitting means 30, for example a groove, which fixes the seal in its position. Each segment preferably has a groove.

[0052] Vacuum channels 24 and / or vacuum distribution chambers 25 are preferably provided in the support plate 22 in order to distribute the negative pressure from a vacuum source, for example a vacuum pump, as evenly as possible across the surface of the support plate and preferably to all segments 19a, b. The vacuum chambers preferably border directly on a surface of the thermal insulation segment 19a, b. The size of this surface preferably corresponds substantially to the size of the adjacent surface. To prevent the segment from being drawn into the vacuum distribution chamber 25 by the negative pressure, at least one support element 27 for the segment is preferably provided in the distribution chamber.

[0053] According to the invention, at least one, preferably several, connecting elements 29 are provided on the cover element, with which the cover element can be mechanically connected to the thermal insulation and / or the carrier plate. This connecting element has a bolt, which, according to the invention, is frictionally connected to the cover element. In particular, this frictional connection is a press connection. The bolt is therefore preferably a press-in bolt. Pressing the bolts into place has proven to be a highly reproducible connection that is significantly more durable than, for example, a welded connection.

[0054] The bolt preferably has an external or internal thread onto which a corresponding element can be screwed in order to clamp the cover element against the thermal insulation and / or the carrier plate and thereby, for example, to improve the contact between the cover element and the heating means.

[0055] Preferably, an opening 28 is provided in the thermal insulation 19, preferably in several segments, through which a connecting element 29 can extend, with which the cover element can be connected to the thermal insulation. For example, the cover element and the thermal insulation can be clamped together to create the best possible contact between the cover element and the heating medium. Alternatively, a certain distance between the cover element and the thermal insulation may also be desired.

[0056] Preferably, a centering opening 31 is provided in the thermal insulation 19, preferably in each segment 19a, b, to align the recesses 23 in the cover element, the heating means, and the thermal insulation. Preferably, a cable duct 26 is provided in the thermal insulation, preferably in each segment, to supply the heating means with electrical energy.

[0057] Figure 8 shows an embodiment of the heating element 20 according to the invention, with a seal 33 that rests against the cover element 32, here the edge 35 and the thermal insulation 19 and / or the support plate 22. This seal prevents, for example, cleaning fluid from entering the space 36 and thus reaching the heating means. The seal 33 runs around the entire inner circumference of the cover element 32. The seal 33 is preferably an endless seal.

[0058] With further reference to Figure 8, alternatively or in addition to the seal 33, the chamber 36 can be connected to an overpressure source, for example for cleaning the heating element or the packaging machine. As a result, the pressure in the chamber 36 is higher than, for example, ambient pressure, so that no cleaning fluid penetrates into the chamber 36. Figure 7 shows a further embodiment of the heating element 20 according to the invention, which in the present case is arranged upstream of a forming station 2. The packaging material is transported along the heating element 20 and then the forming station intermittently by one format length in the direction 37 shown. The format length can vary depending on the desired packaging. The heating element 20 has two segments 20a and 20b. For a longer format length, both heating segments 20a and 20b are activated by a control system; for a shorter format length, only segment 20a is activated.

[0059] List of reference symbols:

[0060] 1 packaging machine

[0061] 2 forming station, deep-drawing station

[0062] 3 Upper tool of the deep drawing station

[0063] 4 Lower tool of the deep drawing station

[0064] 5 Lifting table, carrier of a tool of the sealing, deep-drawing station and / or the

[0065] Cutting device

[0066] 6 packaging tray

[0067] 7 Filling station, insertion station

[0068] 8 Material web, sub-material web

[0069] 9 Lifting device, lifting

[0070] 10 Central area of ​​the heating element

[0071] 11 Lower tool of the sealing station

[0072] 12 Upper tool of the sealing station

[0073] 13 Lower part of the material web clamping device

[0074] 14 Upper material web, cover material web

[0075] 15 Sealing station

[0076] 16 Packaging goods

[0077] 17 longitudinal cutters

[0078] 18 cross cutters

[0079] 19 Thermal insulation

[0080] 19a, b Segments of thermal insulation

[0081] 20 Heating element, segments of the heating element 20a, 20b

[0082] 21 Sealing element

[0083] 22 carrier plate

[0084] 23 Recess

[0085] 24 vacuum channel

[0086] 25 Vacuum distribution chamber

[0087] 26 cable duct

[0088] 27 Support element

[0089] 28 Opening for connecting element

[0090] 29 Connecting element, centering device

[0091] 30 Form-locking means for the sealing element 21

[0092] 31 Centering hole

[0093] 32 cover element

[0094] 33 Seal, especially against cleaning fluid plate surrounding edge

[0095] Overpressure room

[0096] Transport direction

Claims

Patent claims:

1. Heating element (20) for heating the packaging material, in particular a monoplastic film, in a packaging machine with at least one, preferably several heating means and with a thermal insulation (19) and / or a carrier plate (22) and a cover element (32), characterized in that a connecting element (29) is provided between the cover element and the thermal insulation (19) and / or the carrier plate and that the connecting element has a bolt which is frictionally connected to the cover element (32).

2. Heating element (20) according to claim 1, characterized in that the bolt is a press-in bolt.

3. Heating element (20) according to one of claims 1 or 2, characterized in that the bolt has a thread.

4. Heating element (20) according to one of the preceding claims or the preamble of claim 1, characterized in that it has a seal (33) which is provided between the cover element (32) and the thermal insulation (19) and / or between the cover element and the carrier plate (22).

5. Heating element (20) according to one of the preceding claims 4, characterized in that the seal (33) is a circumferential seal.

6. Heating element (20) according to one of the preceding claims, characterized in that the cover element (32) has a plate (34) with a circumferential edge (35).

7. Heating element (20) according to claim 6, characterized in that the seal is provided between the edge (35) and the insulation (19) and / or the carrier plate (22).

8. Heating element (20), in particular according to one of the preceding claims, for heating the packaging material, in particular a monoplastic film, in a packaging machine with a plurality of heating means (20a, 20b), wherein a transport means transports the packaging material intermittently by a specific, selectable format length along the packaging machine and a control which activates the heating elements according to the selected format length.

9. Heating element (20) according to claim 8, characterized in that the heating means which are not activated are provided so as to be coolable.

10. Heating element (20) according to one of the preceding claims or the preamble of patent claim 1, characterized in that a space (36) between the cover element and the heating means and / or the thermal insulation is provided which can be connected to an overpressure source.

11. Packaging machine (1) with a forming station (2), a filling station (7), a sealing station and a longitudinal and / or transverse cutter (17, 18), wherein a material web (8) can be transported along a running direction (20), in particular in cycles, characterized in that it has a heating element according to one of the preceding claims.

12. Method for cleaning a heating element (20) for heating the packaging material, in particular a monoplastic film, in a packaging machine with at least one, preferably several heating means and with a thermal insulation (19) and / or a carrier plate (22) and a cover element (32), characterized in that before and / or during and / or after the heating element is subjected to a cleaning liquid, an overpressure is generated between the cover element and the heating means, the thermal insulation and / or the carrier plate.

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