DE10058566A1 - Foil-wrapped, evacuated thermal insulation body and manufacturing process for it - Google Patents

Abstract

The invention is directed, on the one hand, to a prismatic, in particular plate-shaped, heat-insulating body which is enveloped and evacuated by a gas-tight film, a stable core preformed from a porous material being completely covered by a single blank sheet of the gas-tight film; and on the other hand to a production process for this with the following steps: DOLLAR A a) production of a prismatic core corresponding to the desired shape of the heat insulating body from a porous material; DOLLAR A b) Wrapping the shell side of this core with a single sheet of the gas-tight film; DOLLAR A c) at least partially welding the film pulled tightly around the core along the shell side of the core; DOLLAR A d) Folding the weld area of the film onto the shell side of the core; DOLLAR A e) stress-free collapsing of the areas of the cut of the gas-tight film which protrude beyond the core on the end face, covering the full-area application on the end face core surface (s); DOLLAR A f) welding the folded film areas on at least one end face of the core; DOLLAR A g) evacuating the coated core; DOLLAR A h) complete welding of all remaining openings in the film under vacuum.

Description

The invention is directed to a generally bordered area prismatic, in particular cuboid and / or plate-shaped, of one gastight foil wrapped and evacuated thermal insulation body as well as on a Process for its production.

A high quality insulation is on the most diverse Areas of application needed. In addition to sending refrigerated, medical samples, organs etc. in specially made for this purpose or manufacturable containers is especially the application in the Thermal insulation of buildings is of great importance because of a good one Thermal insulation of primary energy needs can be significantly reduced what an important measure to compensate for the constantly rising heating oil prices represents. A boundary condition for all of these, but also for others Use cases is that heat insulation bodies can be used for this should have as small a volume as possible, which consists of the most diverse, in particular aesthetic and practical aspects follow. The use of Styrofoam panels, for example, are able to withstand the heat losses on the outer walls of the building to reduce, but not to the desired extent, since this is the usual Plate thickness of 5 cm, for example, is not sufficient. at Thermal insulation containers, in which objects during a multi-day Transportes must be kept refrigerated, which is why Proposed use of vacuum insulation panels. Such panels consist of a porous core, which is covered by a gas-tight film and then heavily evacuated. By sucking the air out of the pores, a high one Portion of the potential heat transfer medium removed, and a Heat loss can only be caused by heat conduction within the core structure take place. An important factor in creating and long-term Compliance with the lowest possible heat conduction coefficient is next to the selection of a core material that is as good as possible also one as possible  100 percent gas-tight envelope, so that the vacuum inside a Such insulation panels over a long period of time - at Applications in construction, for example over 50 or more years - maintained remains. It should be borne in mind here that such foil wrappings mostly consist of consist of a plastic substrate that has a sealable on one side Coating and on the other side has a gas-tight metallization. While the film substrate is elastic and therefore more or less stretchable, the metallization layer, which is usually only a few nanometers thick, can be thicker Do not understand stretches or other deformations and get in such a case microcracks not visible to the naked eye, which, however, Reduce the duration of the inner vacuum considerably and therefore that Limit thermal insulation capacity to values that are much too low. In In this context, what has been used in practice deserves Manufacturing processes for such vacuum insulation panels. in this connection is made of two congruent and with their sealable inner surfaces Foil cuts placed next to each other by means of a U-shaped edge a three-way seal along three of the four outer edges manufactured, into which the plate-shaped core is then inserted. As a result, the film blanks are initially adjacent to one another pushed apart, which is particularly true in the sealed corner areas an increased stress for the film, which leads to a stronger at these points Deformation is forced. Then the still open side of the bag sealed within an evacuated vessel. The educated in this way Vacuum insulation panel then has one defined by the thickness of the core Middle area on and an edge area that through the flat and to each other lying and radially outwardly extending welding tabs of the two superimposed foils results. These extend outward Tabs interfere with the joining of several of these at the end Vacuum insulation panels considerably, as they are due to the double film thickness here are very stiff and can therefore be bent at most. This However, bending can only be carried out with the greatest stress for the foils, and the corners even require a multiple twisting to remove the excess Fold the film area inwards. This twisting almost always leads to  an injury to the metallization layer and thus to the one above described effect of a strong reduction in the operating time high Thermal insulation capability.

This results from the disadvantages of the prior art described Problem initiating the invention, generic thermal insulation bodies such to train them so that they can be put together seamlessly with preferably butt-jointed end faces, so that a larger Surface, for example on buildings, completely covered with such thermal insulation bodies can, and at the same time should be on it during the manufacturing process care should be taken to ensure that the wrapping film has as little tensile stress as possible exposed so that the metallic, only a few nanometers thick Diffusion barrier layer of the film can not tear.

This problem is solved in the context of a generic method by means of the following steps:

• a) producing one of the desired shape of the thermal insulation body corresponding, evenly bordered core made of a porous Material;
• b) enveloping the circumferential, in particular jacket side of this core with a single sheet of gas-tight film;
• c) at least partially sealing the film pulled tightly around the core along the circumferential, in particular jacket side of the core;
• d) folding the weld area of the film to the circumferential, in particular the shell side of the core;
• e) stress-free folding of the overhanging overhang on the core Areas of the cut of the gas-tight film covering the and full-surface application on the end, especially the front Core surface (s);
• f) sealing the folded film areas on at least one End, in particular end face of the core;
• g) evacuating the coated core;  
• h) completely seal all remaining openings in the film Vacuum.

The invention thus turns away from the method of forming a Foil pocket in which the core with one end face and with its entire jacket has been inserted so far. Instead, a core with the desired shape of the heat insulating body, and then this successively enveloped by a single, initially flat film blank. The core is initially complete in a circumferential or jacket area surrounded by the film and then to an approximately tubular welded together around the core circumference, the other two Openings in the area of the end or end faces of the thermal insulation body having. Before sealing these end faces further, the protruding areas of the film completely by suitable folds folded the relevant end or end faces of the core so that they are a experience full-surface support, due to the flat edge of the Ideally, the core and edges that are as sharp as possible, ideally none at all Curvatures of the film occur; rather, it can be folded along edges are and therefore experiences both with this folding and with the subsequent evacuation nowhere a function of the metallic Diffusion barrier layer tensile stress. Because the film substrate itself is only a few micrometers thick, the deformations at the folded edges are such low that the metallic coating can easily understand this can. After the sealing on the front, one remains approximately perpendicular to the Protruding welding tab, which, however, extends straight and merges into the adjacent foil areas via an approximately rectangular edge. As a result, the subsequent folding of this welding strap to the relevant end faces of the core largely stress-free and thus without risk damage to the metallization layer can be carried out. Finally it is not difficult for the largely closed off in this way Body through a section of a weld seam that is temporarily not yet sealed to evacuate and then this remaining welding section under Closing vacuum. By so all welding tabs stress-free to the  Core surface are folded up, where they are then fixed, for example, adhesively can, the shape of the finished thermal insulation body largely by the Shape of the prefabricated core defined. In the area of the front side plate-shaped thermal insulation bodies do not remain protruding Sweat tabs so that there is no difficulty in such Thermally butt to join together, whereby in the area between each two thermal inserts placed next to each other no thermal bridges remain.

It has proven to be advantageous for the core to be pressed from a powder. Because of the adjustable compression during the pressing process, this is the first step powdery granules are initially compacted in such a way that there is one for the further Processing has sufficient stability, while on the other hand sufficient number of spaces between the individual particles remains, which also communicate with each other and therefore easily can be evacuated to optimize the thermal insulation of the material. There is a comparatively low, mechanical stability of the material uncritical, because the film-wrapped and evacuated core by the external air pressure undergoes a high degree of mechanical stability. The powder can either be pressed within a mold so that it immediately takes the final shape of the Receives thermal insulation, or it can be pressed, for example, the then get the final shape by sawing and / or cutting.

In another embodiment, it can be provided that the core consists of an open-pore plastic foam. With this Manufacturing processes can also use cores for thermal insulation bodies make complex shape.

The invention can be further developed in that the core of the Thermal insulation body with a gas-permeable filter paper or fleece is wrapped, which retains loose particles of the core during evacuation. There never ensured for both pressed and foamed cores may be individual particles or flakes during the evacuation phase  To be released from the bond and carried away is a precaution required to keep the sealed seams clean, and here is a wrap of the core with a paper or nonwoven fabric proven in this way detached particles as in a filter.

It has been proven that the core is coated using the gas-tight film is covered by a thin plate made of cardboard, for example. Such a box protects the core when it is handled during the Manufacturing method according to the invention, and it also ensures smooth outer surface of the core without any elevations, which during the Evacuation process pierce the wrapping film or at least its Could damage the metallization layer.

The invention also offers the possibility that the core before wrapping by means of the gas-tight film with an edge protection from a comparatively hard, especially organic material, e.g. B. cardboard is provided. On such edge protection increases the stability of the exposed areas of the Thermal insulation body according to the invention with respect to external mechanical Effects particularly due to improper handling.

By cutting the gas-tight film from a long film web, the Width is greater than at least twice the minimum width of a welding track the distance between two opposite end faces, in particular end faces of the preformed core, is an assembly line-like production according to the invention Thermal insulation body possible, which results in large quantities cost-reducing effect. Ideally, such Foil sheet always cut rectangular pieces, which are then each a core is completely led around and closed on all sides, so that little film waste occurs with such processing.

If the core and / or the film before sealing at temperatures around 100 ° C to 200 ° C, it is ensured that no moisture in the subsequently evacuated core remains, which increase the gas pressure and  so that the insulation function would deteriorate. The result is a product with a maximum service life.

The invention recommends that in the context of the end, especially the front Folding the to the shorter end, especially the front edges adjacent film areas are first folded inwards. hereby is the formation of lateral protrusions on the relevant end face avoided so that to completely fold a welding strap to the Only one surface of the thermal insulation body according to the invention Folding is required, which causes the stress caused by the manufacture for the Foil can be further reduced.

If the end, especially the front, folded and sealed Foil areas are folded up to the surface of the core, the Thermal insulation body according to the invention bordered on all sides by flat surfaces and can therefore be bluntly adjacent to adjacent end faces Thermal insulation bodies are pushed up.

The weld seams folded up onto the surface of the core are preferred adhesively attached to the film layer underneath. This measure serves to fix all folded areas. Naturally, it is complete sufficient if the areas folded last over a surface, e.g. folded welding tabs, are fixed in such a way that they are then simultaneously protect all surrounding folding areas.

The thermal insulation body is completely covered except for a single opening then to a partial vacuum below 100 hPa, preferably evacuated below 10 hPa, especially below 1 hPa. This strong vacuum not only improves the thermal insulation ability of an inventive Thermal insulation body significantly, but it also increases its mechanical Stability as the core is constantly subjected to all-round compression. At the same time, however, this strong vacuum poses a challenge for that Sealing ability of the wrapping film, which is only by the  According to the invention, stress-free manufacturing processes corresponded to the film can be.

A flat surface produced by the method according to the invention edged, generally prismatic, preferably cuboid, in particular plate-shaped, and enveloped by a gas-tight film evacuated thermal insulation body differs from known Thermal insulation bodies in that a stable, made of a porous, especially open-pore preformed core from a single Blank sheet of a gas-tight film is completely wrapped, two End faces remain free of folds and / or sealed seams.

The use of a single blank sheet has compared to that from the State of the art, welded together in two pockets Cutting sheets based principle have the advantage of being a far better one Adaptation to different core forms is possible, while the Welding effort can be reduced, and besides, it is through that Subsequent wrapping of the core possible through the single film cut to use the core for support during folding and to tighten the film pull so that when the core shrinks due to evacuation, only one minimal wrinkling in the film is to be feared. All-round support the core allows the formation of largely flat surface and end faces are ideal for putting together similar thermal insulation bodies Suitable for insulation of larger areas.

The core can be pressed from a powder, for example from pyrogenic silica. Such pyrogenic silica combines sufficient mechanical Stability with a sufficiently low coefficient of thermal conductivity moderate evacuation pressure (1-10 mbar), and it is ideal for Manufacture of compacts of various shapes.

On the other hand, it is also possible for the core to be foamed from a plastic is, for example. Made of polystyrene or polyurethane. Such materials have  proven because they are chemically stable, sufficient mechanical strength bring and are able due to their open pores gases during to deliver an evacuation process at sufficient speed.

If possible, all edges of the core should be formed with sharp edges Edge radii of less than 1 to 2 mm. With such sharp edges between The individual, flat surfaces of the core ensure that a film with a few, pre-defined folds fully folded onto the core surface can be achieved without this resulting in unpredictable tensile loads. It is an important feature, which in turn is a sufficient, mechanical stability of the core. Because the film should - as already mentioned above - be stretched tightly around the core, with just the Edges are subjected to an increased deformation force. The core, however, can be provided with such a mechanical stability, since it is outside the film and thus can be made under sufficient pressure if necessary.

The invention further provides that in a particular embodiment all Circumferential, in particular jacket sides of the core exclusively with outer edges, d. H. Edges with a convex curvature can be formed. This can Ensure that a tightly stretched film is attached to the core on all sides creates and is not lifted from its surface, such as Grooves or other recessed surface areas of the core could.

A further optimization can be achieved by making the core like this is designed so that the sum of the surface angles of two each on the same End or end face adjacent corners is 540 °, especially the The sum of the surface angles at a corner is 270 °. This Construction specification is based on the knowledge that in the area of a corner there is a discontinuity when the adjacent film areas are folded up to the body surfaces to at least partially overlap the film must lead. Provided that this regulation is complied with, a straight line can be used Edge of the protruding film area, as when cutting the  relevant film cut from a long film web is ensured that, for example, a middle running between these corners Sweat tab gets a constant width, making optimal The requirements for a welding process are met.

Mutually congruent sides on opposite areas of the core allow a seamless installation of several thermal insulation elements. As a result, the formation of Thermal bridges inhibited.

In practice, plate-shaped cores are of the greatest importance, with the Distance between the plate bases is constant. This will make the front welding tabs along an intermediate plane between them two plate bases, and so there is in the area between two corners symmetrical to this intermediate plane Conditions that favor a uniform folding.

It is within the scope of the invention that the plate bases are rectangular. This allows the above corner condition for plate-shaped core shapes be respected.

A core geometry, with the edges between a face and the adjacent plate base side of the core are rectangular, has the consequence that one by folding towards the core while observing a parallel one Edge guidance of the outer or free edge of the one placed against the other Film protrusions formed welding tab exactly in the middle between the two Plate base sides of the core is located. This makes it possible to have an end face Fold the sweat flap over to one side of the plate, the opposite welding tab, however, to the other side of the plate, see above that in the case of such butt-jointed panels, the panels face each other bordering, folded welding tabs do not overlap, but lying side by side, which is a particularly intimate pushing together Adjacent thermal insulation body allowed.  

If the melting point of the core is above the melting point of the sealable part of the film is completely excluded that during the Welding deformations of the core could occur, which too lead to unpredictable changes in shape of the finished thermal insulation body could.

With great advantage, the film is designed as a composite film with a lower melting coating on the inside. This will damage the actual film substrate avoided during a welding process. The lower melting topping is by heating in a more or less liquid state, and by merging the superimposed Enamel layers are reduced on the one hand and the surface tension on the other hand, a complete seal of the contents to be evacuated achieved that due to their large width practically impossible for gas diffusion makes.

According to the invention, the film has a gas-tight outside Metallization on. This can be an aluminum layer, for example, which has a thickness of at least a few nanometers. That’s it possible to make the film substrate very thin, causing it to fold can be made without any strain.

The film blank is preferably rectangular. Such a design allows successive cutting of such film cuts from one elongated, continuously fed film web. In a borderline case it is also conceivable instead of a rectangular film cut To use parallelogram-shaped cuts, also from a single one Web can be separated continuously, or trapezoidal Blanks in which successive blanks each provide their orientation switch so that the trapezoid base alternately on the left and right Foil sheet lies.  

According to the invention it is further provided that the taut around the core Foil is sealed along a circumferential, in particular outer surface of the core. By placing the welding tab away from the jacket edges into a jacket surface is relocated into, the stress during the subsequent folding up one Such welding tab on the thermal insulation body can be minimized.

A further feature according to the invention is that, on an end face running between the base plates of the plate, the width B of the area of the cut of the gas-tight film on at least one jacket end edge, which protrudes beyond the end plate, in particular the end side, corresponds to the following dimension:

s + [(h / 2). (1 / sin β). (1 + cos β)] ≦ B ≦ h / sin β,

in which:
h = distance between the parallel plate bases
s = width of the welding lug required for a proper weld
β = edge angle at the relevant jacket-forehead edge.

This design rule consists of two partial inequalities, observing them ensures that the width s of a weld pocket is sufficient for the welding device, however, is still narrow enough to fully adhere to the to be able to fold up the relevant end face. It was takes into account that in the case of an inclined end face between mutually parallel plate bases on the acute-angled jacket front Edge a smaller overhang B exists when the core is at the shell side Wrapping with its jacket edges aligned perpendicular to the film web axis was. Even if this means that the edges of the Protruding during the formation of a welding strap the latter no longer on the Middle plane lies between the two plate bases, but to the acute-angled edge is shifted, so the suitability for the Welding process as well as the suitability for complete folding over the  to the obtuse-angled edge, the frontal foil section ensured.

Draw the high quality thermal insulation body according to the invention is characterized by the fact that the end, in particular the front, over the core protruding areas of the cut of the gas-tight film while covering the and full-surface contact with the end, in particular the front surface (s) of the preformed core are folded together without stress. The possibility of one such stress-free folding is thereby within the scope of the invention created that the front film protrusions before sealing and thus individually folded, the stress is significantly lower than that folding together in the sealed state. Even afterwards The welding flap is brought up to the adjacent foil areas classified as uncritical because on the one hand the folding edge used for this Formation of the welding tab was already created before the welding process and on the other hand, a film area is only stretched straight during this other film part is compressed at best. Because the relevant bending edge already is present, the film part to be stretched does not have to stretch execute, contrary to the prior art, where by the complete New formation of a kink after sealing extremely unfavorable Force relationships prevail.

If the welds in the area of the end faces, especially the front faces, for example run parallel to each other, the shape of the sealed end faces created so that they slide together two such adjacent thermal insulation bodies as the parts of a puzzle interlock and therefore leave no thermal bridge.

The idea of the invention allows further training in that the Welds in the area of the end faces, in particular end faces, approximately parallel to of the circumferential, in particular lateral surface, on which the circumferential, in particular jacket-side weld is located. This is a the shortest possible course of all welds ensured. As special  It has proven to be advantageous if the front weld seams are parallel run to the base sides of a plate-shaped thermal insulation body and the jacket-side weld along one of the large-area base plates, there in such a case that for the blunt installation of several thermal insulation bodies important end faces of the thermal insulation body as little as possible of that Ideally deviate from a completely flat surface. Because the foils before sealing are individually folded over, is the additional strength in the overlapping area minimal and can almost be neglected. They can also be Predict overlapping areas and if necessary by appropriate minimal recesses within the prefabricated. Take into account the core.

The inventive folding run in the area of a corner of the preformed core five folded edges together. Two of these correspond Folded edges of one edge of the core in the area of this corner, two more In the final state, folded edges follow the third edge in this corner area, and the fifth folded edge separates two, preferably congruent Angular areas caused by folding away the excess film area of the corner in question.

The folding according to the invention is further characterized in that one of the Folding edges with an angle between 30 ° and 60 °, preferably of about 45 ° includes at least one, preferably two adjacent folded edges. It this is the last of the folding edges described above, which the separates the two preferably identical angles from one another. That angle defines a part, preferably half, of the film area to be folded away at the corner in question and can therefore, depending on the geometry of the concerned Corner fluctuate within more or less large limits. Because with that core according to the invention does not have two adjacent surfaces absolutely have to stand perpendicular to each other, but at least on the other hand should not meet at an exaggerated acute angle since they are exposed in this way If the risk of damage was particularly high, the angle moves of the film area to be folded away in a more or less narrow  Tolerance range, being at a corner with completely perpendicular to each other an overlap angle of 45 ° can be found at the core edges that meet.

When observing the above regulations for film overlap width B two of two neighboring ones below one end of the welding tab Folding edges starting on both sides of the welding flap outside the relevant end edge, especially the front edge. As stated above one begins at each corner of the core to none of the adjacent core edges parallel fold edge, and with a stress-free fold such a "skewed" Fold edge on one each from an adjacent corner, likewise "Skewed" fold edge meet, outside of the two corners connecting edge. The two oblique folded edges end at this meeting point and are ideally made by folding edges parallel to the edges of the core continued. This results in a triangular fold area, which corresponds to one of the relevant connecting edge can be folded over adjacent surfaces. For this purpose, the surface along which the relevant, frontal weld runs.

Also on the outside of the relevant end edge, especially the front edge meeting point, a total of five folded edges converge. Two of these Folding edges limit the folding triangle described above, while two fold lines which are preferably symmetrical to one another, each over a part limit this folded triangle folded overlap area, and the last this folded edge runs radially through the adjacent welding tab outside and either forms its outer boundary edge or delimits one due to the folding-out, end-side overlap area of one Welding flange.

If the folded edges run in this way on the end faces, in particular end faces, that foil sections always with two inner surfaces or with two outer surfaces can lie next to each other on any desired path Weld seam should be arranged as all sealable areas of this area  are always covered by a likewise sealable surface and thus a Allow the lower-melting coatings to flow together.

Further advantages result from the fact that the shorter end, especially the front edge of the adjacent film areas at the bottom are folded over. As a result, it is possible to limit those in the area of To fold overlaps to be folded away to the relevant end face, so that the parallel to the longer end- especially front edges Sweat flap ends at these shorter end and especially front edges therefore folded up to the relevant end face in a single operation can be.

For airtight closure of the film-coated thermal insulation body on the End faces are the folded foil areas at the end, especially end faces of the core sealed. In contrast to the state of the In the case of the invention, technology is waited with the sealing on the end face until the single layer film is folded as close to the core as possible subsequent folding stress as low as possible. At a Embodiment where the base sides of a flat thermal insulation board as End faces in the context of the manufacturing method according to the invention can be used, the butt joints on the narrow sides of such Except for the only jacket weld seam remaining there, the insulation board is completely be made wrinkle-free, making the joining together more uniform Insulation boards without any thermal bridges in the intermediate areas is favored.

By folding and sealing the ends, especially the front ends Folded film areas to the relevant end, in particular the end face are, the shape of the thermal insulation body predetermined by the core approximated exactly as possible, so that with the invention Thermal insulation bodies also tightly defined, geometric tolerance ranges can be met.  

The invention can be supplemented by the fact that the surface of the core folded seams adhesive to the film layer underneath are set. This ensures that even during a long period Storage time the folded welding tabs do not straighten up again, and could hinder the installation of such a thermal insulation body.

The invention is advantageous in that the jacket-side weld is formed from several sections, which are overlap and / or overlap. Within the scope of this inventive concept it is possible to initially only cover the welding flap in the area of the two Seal the end faces of the core to be encased, if necessary on the outer surface fold up and, if necessary, fix it there adhesively, so that the front Folds and seals can be done properly. However, an opening remains approximately in the middle of the jacket-side weld seam, used for large-scale evacuation of the gas volume still contained can be. The remaining can then inside the vacuum container Opening still to be fully welded, with overlaps and / or overlaps with the initially produced partial weld seams ensure that the interior of the evacuated thermal insulation body is hermetically sealed.

The partial vacuum in the evacuated thermal insulation body should be below 100 hPa, preferably below 10 hPa, in particular approximately 1 hPa. This very low pressure has the consequence that with the invention Thermal insulation boards with a thickness of, for example, only 2 to 4 cm the same Thermal insulation cannot be achieved as with a ten times thicker, not evacuated styrofoam body.

To perfect the thermal insulation body according to the invention it should be provided that its surface is profiled, e.g. corrugated, is provided. This profiling can in particular be carried out by profiling the Core come from and serve a variety of purposes, for example  Improvement of the adhesive properties to be glued or otherwise fixed Cover layers such as wallpaper or the like to improve the Sealing properties in the area of butt joints, etc.

Finally, it corresponds to the teaching of the invention that at least one extension the film covering is provided, which is welded to a appropriate extension of an adjacent thermal insulation body allowed. This can be in the area of an end seal act protruding area of a film part of a welding tab, the Formation of a joint weld seam with a protruding one Overlapping edge area of an adjacent thermal insulation panel can be joined together.

Other features, details, advantages and effects of the invention will be apparent from the following description of preferred embodiments of the Invention and with reference to the drawing. Here shows:

Figure 1 is a schematic representation of a system for producing thermal insulation body according to the invention.

FIG. 2 shows detail II from FIG. 1;

FIG. 3 shows the welding apparatus of Figure 2 during the welding operation.

Fig. 4 shows the heat insulation body according to folding the weld produced in accordance with 3 Fig.

Figure 5 illustrates the production of a stress-free, face-side folding in a first embodiment of the invention in a first folding phase.

FIG. 6 shows a second phase in the folding according to FIG. 5;

. Fig. 7 is a subsequent, third phase in the folding of Figures 5 and 6, so that there is an upright, sealable flange;

Fig. 8, the folding of the welding lug of Figure 7 subsequent to the welding operation.

Fig. 9 is another possibility according to the invention for producing a stress-free, face-side folding in an intermediate folding stage, in whose connection there is a raised, sealable flange;

Fig. 10, a first folding of the welding flange of Figure 9 following the welding operation.

Fig. 11 shows a further pre-folding a portion of the welding flange against the end face of the insulation body;

Fig. 12 the entire thermal insulation body in the folding state shown in FIG 7 or 9 after carrying out the end-face seal.

FIG. 13 shows detail XIII from FIG. 1; such as

FIG. 14 is the finished heat insulation bodies in plan view;

FIG. 1 shows a schematic view of a production line 1 for the production of thermal insulation bodies 2 working according to the method according to the invention, for example of the plate-like shape shown in the top view in FIG. 14.

Not shown is a shaping process with which a core 3 is pressed from a powder, for example pyrogenic silica, or from a plastic, for example from polystyrene or polyurethane. This core molding can already have the desired shape of the thermal insulation body 2 to be produced or can be reworked for this purpose, for example sawn or cut. The core blanks should correspond as exactly as possible to the desired shape of the final thermal insulation body 2 ; at most, shrinkage during the evacuation phase of the order of magnitude of approximately 5% can be compensated for by appropriate oversizing.

The core blanks 3 are removed from an intermediate storage and are first covered in a fleece in a first processing station 4 . This has the task of holding back any particles that may have been released from the core composite during the later evacuation phase and thereby protecting the evacuation system from damage.

The core blank 3 is then transported 7 from a conveyor device 5 to a drying station 6 . Here the cores 3 covered with the fleece 8 are heated to a temperature between 100 ° C. and 200 ° C. in order to completely expel any residual moisture that may still be present. Then the nonwoven-coated cores 3 travel 7 to a wrapping station 9 , where the dried cores 3 together with their nonwoven covering 8 are wrapped in a plastic film 10 . The plastic film 10 consists of a plastic substrate which is provided with a sealable layer of a lower melting plastic on one side and additionally with a preferably metallic diffusion barrier layer which is embedded in the substrate and / or is covered with one or more protective layers, preferably made of plastic. The film 10 is wound on a roll 11 , and its width in the present case corresponds to the envelope of a cuboid core 3 the sum of its width b measured transversely to the film web 10 plus its height h measured perpendicular to the conveying direction 7 plus two times that width of a welding strap required for sealing s. On the other hand, this welding lug width s should be equal to or less than half the height h of the core 3 .

The foremost edge 12 of this very long film web 10 is fixed, for example, to a welding jaw 13 arranged above the conveying device 5 . At this point in time, the other welding jaw 14 and the film roll 11 are located below the conveyor device 5 , so that the core 3, which is moved further, takes the film 10 with its front edge 15 approximately to the position shown in FIG. 2. Then the welding jaw 14 swivels upwards through a gap in the conveyor device 5 , which can be designed, for example, as a roller conveyor, and at the same time a delayed release of the film 10 can be achieved by braking the film roll 11 , so that it always remains taut. When swiveling up, the welding jaw 14 approaches the fixed welding jaw 13 , and finally these two elements are pressed together, as shown in FIG. 3, and the mutually adjacent welding layers of the film 10 fuse under thermal influence. Outside the weld seam, the film 10 surrounding the core 3 is cut off from the remaining web 10 .

Next, the welding flap 17 , which initially still protrudes vertically from the upper plate base surface 16, is folded up onto the upper side 18 of the thermal insulation body 2 , as shown in FIG. 4, and can be adhesively fixed in this position, for example by means of a hot glue. In this context, it should be noted that the welding jaws 13 , 14 can also be designed such that there is no continuous weld seam, but rather an interrupted weld seam 19 , as is shown in FIG. 12 on the folded-over welding flap 17 . As a result, an opening 22 remains between the two welding sections 20 , 21 , through which the air contained in the core 3 can be extracted at a later time.

In the conveying direction 7 now further processing station 23 follows, in which the end faces 24 of are on the casing side 25 is already covered by the film 10 wrapped core 3 by the output of the wrapping station 9 laterally projecting film edges and sealed.

According to a first embodiment of the invention, this lateral closure can be carried out according to the method steps shown in FIGS. 5 to 8. In a first phase ( FIGS. 5 to 7), the protruding edge region 26 is folded in such a way that on the one hand it completely covers the end face 24 in question and on the other hand it is folded into a flat welding flap 27 which projects approximately perpendicularly from it. This welding tab 27 is then closed by means of a welding device (not shown), and finally the welding tab 27 is folded up towards the end face 24 , as shown in FIG. 8.

The inventors have found that for the formation of an optimal covering of the end face 24 , ie a curvature-free, plane-parallel contact of the film 10 , and for the formation of a welding tab 27 which is equally suitable for the welding process, ie a flat tab with a constant width Convolution strategy offers special advantages. This is shown in FIGS. 5 to 7.

From FIG. 8 it can be seen that a welding tab 27 is optimal if its width s is less than half the height h of the plate-shaped thermal insulation body 2 , since in this case it can be folded up completely onto the face 24 in question and not over its edge 28 survives. For the same reason, it is important that the end edges 29 of the welding tab 27 do not protrude beyond the adjacent end face 15 of the thermal insulation panel 2 .

In solving the partial task defined in this way, the inventors proceeded from the knowledge that a total of three sides 15 , 16 , 24 abut each other in the area of each corner 29 of a core 3, in particular a cuboid. Since in a cuboid every corner represents a right angle, the sum of all angles β ₁ , β ₂ , β ₃ colliding at such a corner 29 is defined 1:

β ₁ + β ₂ + β ₃ = 3.90 ° = 270 °.

On the other hand, since the film completely surrounds its point lying on the corner 29 and thus along a circle of 360 °, an excess area of 90 ° remains, which is folded away according to the present invention, so that the film 10 is not cut, for example, from the rectangular one Shape must be processed differently. This principle of folding away has the advantage that it is ensured that the film cannot have any opening at this point through which air could later penetrate into the evacuated thermal insulation body 2 .

The folding away takes place in that the excess angle, which in the case of a cuboid is 90 °, is absorbed on one of the three sides, in the present case on the end face 24 , by a multilayer area of the film 10 . In one area, the end face 24 is therefore not covered by a single film layer 10 , but by a triple film layer. The two additional film layers 30 , 31 can be seen in FIG. 5 on the basis of the adjacent folded edges 32-34 . In this case, a middle folding edge 34 which runs obliquely with respect to all the edges 28 , 35 , 36 abutting the corner 29 divides the excess and therefore foldable film area 30 , 31 into two equally large angles α ₁ , δ ₁ , in the present case:

α ₁ = δ ₁ = 45 °.

As can be seen from FIGS. 5 to 8, the folding is completely symmetrical with respect to a central plane running between the two plate bases 16 , 37 and parallel to them, so that at the corner 38 of the core opposite perpendicular to a central edge 36 with respect to this central plane 3 mirror-image folds occur, the fold edge 32 in particular coinciding with the fold edge starting from the first corner 29 under consideration. Since the folded edge 33 in the state according to FIG. 7 runs parallel to the folded edge 32 or the core edge 36 , this must enclose a right angle to the core edge 28 , which in turn runs at right angles to the core edge 35 . Folded edge 33 thus runs coaxially to core edge 35 and thus parallel to the opposite folded edge 39 , based on the still completely unfolded edge projection 26 . Because of the right angle β ₂ and because of the cuboid shape of the core 3, the edge protrusion 26 of equal size on all sides results in a rectangular film region 40 between the two outer surfaces forming the welding lug 27 , which must be folded in between the two welding lug cover surfaces as little as possible.

For this purpose, a triangular region 42 defined by the folding edge 32 , the oblique folding edge 34 and the folding edge 41 , which is symmetrical with respect to the core center plane, is first folded onto the end face 24 of the core 3 , as shown in FIG. 6. This covers, on the one hand, the triangular film region 31 and, on the other hand, the film region 43 that is mirror image, so that their initially upper boundary edges 44 finally abut one another. Since the triangular areas 31 , 43 each cover the triangular areas 30 , 41 due to the overlap, these triangles must be congruent. Since the angle at the upper tip 45 of the triangular area 42 is 90 ° in the present case due to the sum of the angles in the triangle 42 , the angles of the adjacent triangles 31 , 41 starting from this point 45 must each be 45 °. For this reason, the folding edges 44 run with respect to the originally unfolded state of the edge region 26 horizontally or parallel to the end face 24 . The triangles 30 , 31 , 41 , 43 are therefore isosceles triangles without exception, and for this reason the corner points of the horizontal folding edges 44 falling on the initially vertical folding edges 33 , 39 reach the center point 46 in the final folding state according to FIG. 7 the folded edge 32 . The upper part of the right-angled film area 40 above these folded edges 44 therefore folds easily and in the manner of an accordion between the top surfaces of the welding tab 27 , as shown in FIGS. 6 and 7. In this case, the inner areas of the film which can be sealed are always adjacent to one another or the outer areas of metallized film so that complete sealing is possible without impairing the metallized layer.

In the illustrated example of a cuboid core 3 there are particularly simple ratios since the angles α and α _{2 are} each 45 ° and thus the triangle 42 is isosceles. In other forms of core 3 , the conditions for folding also change. If, for example, the angle β _{2 increases} , for example because the end face 24 runs obliquely between the two plate base surfaces 16 , 37 , the sum β ₁ + β ₂ + β _{3 increases} , so that the area to be folded away and thus also the angle α ₁ is reduced accordingly. If at the same time β to the angle of ₂ complementary angle γ ₂ at the opposite corner 38 is reduced, because both plate base sides 16, run 37 parallel to each other, so increases in accordance with the angle α _2, and therefore, ideally, the angle remains the triangle 42 at the tip 45 unchanged 90 °. However, this is no longer on a central plane between the two plate bases 16 , 37 , but is shifted towards the more exposed edge 28 . However, if care is taken at the same time that the two upper edges 47 , 48 of the overhang 26 lie congruently on one another during the folding, the welding lug 27 also shifts to the exposed edge 28 due to the different overhang B on the two plate base surfaces 16 , 37 the triangle tip 45 again lies on the folded edge 48 that locates the welding tab 27 . This means that the folding principle can be maintained qualitatively.

On the other hand, if the corresponding corner angles β ₁ , γ _{1 increase} because the plate bases 16 , 37 are not rectangular, the sum of the angles at the corners 29 , 30 increase equally, and the corresponding triangle angles α ₁ , α ₂ decrease accordingly. As a result, the triangle 42 to be folded inwards is no longer rectangular, but - at otherwise right angles β ₂ , γ ₂ , β ₃ , γ ₃ - the tip 45 of the triangle 42 is again on the central plane between the plate base surfaces 16 , 37 . This case is more unfavorable, since in such a case the overlapping triangles 31 , 43 also become smaller, and consequently the folding edges 44 - in relation to the originally unfolded state - do not run horizontally, but rather incline downwards from the tip 45 . This also leads to the fact that the inner folded edge 49 no longer runs perpendicular to the end face 24 in the state according to FIG. 7, but rather is inclined towards the relevant side center. This in turn has the consequence that the upper edges 47 , 48 of the edge projection 26 no longer run parallel to the end face 24 , and consequently the welding tab 27 no longer has a constant width s.

Finally, if one or both corner angles β ₃ , γ ₃ on the end face 24 change , so that the core 3 takes on a wedge-shaped shape, the width s of the welding tab 27 also changes , since in this case the width h to be covered by the constant overhang 26 the end face 24 varies in the longitudinal direction thereof, which is only possible by an opposite change in the welding lug width s.

As can be seen from the above considerations, different changes in the geometry of the core 3 have different effects on the design of the welding tab 27 . However, it has been shown that these effects can be neglected, at least with regard to the quality of the folding, if the sum of the side angles at adjacent corners 29 , 38 of the core 3 remains constant at 540 °:

β ₁ + β ₂ + β ₃ + γ ₁ + γ ₂ + γ ₃ = 540 °.

As a result, the triangle 42 , which is preferably to be folded inward, remains at a right angle at its tip 45 , so that the folding edges 44 emanating from here run in a common alignment, accordingly the folding edge 49 in the state according to FIG. 7 is perpendicular to the end face 24 , and in addition General vertical top edges 47 , 48 of the edge region 26 run parallel to the end face 24 , which is synonymous with a constant welding lug width s. An inclination of the folded edge 49 with respect to the upper edges 47 , 48 of the edge region 26 which affects this result can be caused by the even more severe geometry condition

β ₁ + β ₂ + β ₃ = γ ₁ + γ ₂ + γ ₃ = 270 °

of core 3 can be avoided.

In addition to the above-described conditions for the sum angles at adjacent corners 29 , 38 , which ensure a constant width s of the welding flap 27 when all other folding conditions are observed, and which must be taken into account when designing the core 3 , the film must also be provided 10 determine their total width as precisely as possible, whereby the following dimensioning rule has proven itself:

s + [(h / 2). (1 / sin β ₂ ). (1 + cos β ₂ )] ≦ B ≦ h / sin β ₂ .

Such a width B of the film region 26 protruding from the relevant edge 28 guarantees that after completion of the folding, approximately in the state according to FIG. 7, the remaining welding tab 27 has a width s sufficient for the execution of the weld seam 50 , and that this weld seam width s can be folded up to the end face 24 without protruding over one of the longitudinal edges 28 delimiting them. Since this condition has not been observed in the example shown, the welding flap must be cut off here before or after folding over according to FIG. 8, so that folding over around the core edge 28 is not necessary.

As explained above, in the folding according to FIGS. 5 to 8, the excess film area 40 is folded at the bottom over the end face 24 and with its upper area between the end areas of the welding tab 27 , so that after the weld seam 50 has been produced, only the welding tab is folded over 27 around the lower edge 48 of which is required.

In another folding technique, which is shown in FIGS. 9 to 11, the film areas 51 protruding on the longitudinal edges 28 of the end face 24 are first folded to one another at the end face 24 , thereby forming a welding flap 56 , and the excess film area 52 becomes folded out beyond the adjacent end face 15 . The resulting triangle 53 is in alignment with the end face 24 and, like the triangle 42 of the folding technique described first by the folding triangles 31 , 43 there , overlaps here by the further folding triangles 54 . A vertical, double-layer film area 55 , which represents an extension of the welding tab 56 , then adjoins this upper film triangle 54 . Here, too, the film areas 10 lie against one another over the entire surface exclusively with sealable inner sides and can therefore be sealed comfortably. Once this has been done, the welding flap 56 is folded over its base edge 57 , as shown in FIG. 10, and finally the area 52 formed by the lateral protrusions 53-55 around the relevant end edge 36 of the core 3 in the direction of the Front side 24 folded over, as shown in Fig. 11. Here, too, it can be seen that the above condition for the edge projection B was not met and requires an additional cutting process.

Although the latter folding method is possible in principle, it is less recommended by the inventors, since the welding flap 56 has to be folded over twice, as a result of which the metallized diffusion barrier layer could be exposed to the risk of damage.

Following the method step of closing at the end in the processing station 23 , the core 3, which is completely covered by the film 10 except for the opening 22 , is then placed in an evacuable vessel 58 in such a way that the region 59 of the jacket-side welding flap having the opening 22 17 is erected approximately perpendicular to the relevant plate base surface 16 , as shown in FIG. 13. This can be done, for example, by separating the area 59 of the welding tab 17 to be erected by short cuts 60 from the adjacent, already sealed sections 20 , 21 and then bending it upward to form an additional fold. This region 59 , which has the opening 22 , is placed between two welding jaws 62 , which, however, have not yet been moved together. Rather, the vessel 58 is then closed and evacuated to a pressure between about 0.1 and 1 hPa. A period of, for example, 20-120 seconds is then waited so that the air initially contained in the core 3 has the opportunity to emerge at the opening 22 as a result of the pressure difference compared to the vacuum.

As soon as the pressure equalization has taken place and the core 3 has also been evacuated, the two welding jaws 61 , 62 are moved together remotely and the welding process is activated. A further weld seam 63 is thus produced, which runs parallel to the first two welding sections 20 , 21 , but is preferably offset in the direction of the free edge 64 of the jacket-side welding tab 17 . Since, when the original welding sections 20 , 21 are produced, the opening 22 has been delimited over almost the entire width of the welding tab 17 at the edges of the remaining opening 22 by means of welding seams 65 running approximately perpendicular to the longitudinal direction of the welding neck 17 and reaching as far as the edge 62 , In the final sealing 63, a crossover with the vertical weld seams 65 forming the opening edges can be easily achieved, so that an absolutely tight sealing of the heat insulating body 2 is guaranteed.

Finally, the tab area 59 containing the original opening 22 is also folded up onto the relevant flat side 16 of the thermal insulation body 2 and fixed there by means of a hot glue. The thermal insulation body 2 is thus completed and can be subjected to a quality inspection at an inspection station 66 .

Of course, instead of evacuation via an opening 22 in the jacket-side weld seam, evacuation could also take place via one of the front-side weld seams.

Claims (47)

1. A method for producing a flat-edged, generally prismatic, preferably cuboid, in particular plate-shaped, heat-insulating body ( 2 ) enveloped and evacuated by a gas-tight film ( 10 ), characterized by the following steps:

• a) producing a core ( 3 ) with a flat surface and corresponding to the desired shape of the heat-insulating body ( 2 ) from a porous, in particular open-pored material;
• b) enveloping this core ( 3 ) along a circumference, in particular along its jacket ( 25 ), with a single sheet of the gas-tight film ( 10 );
• c) at least partially sealing ( 20 , 21 ) or welding the film ( 10 ) drawn tightly around the core ( 3 ) along a peripheral, in particular lateral surface ( 16 ) of the core ( 3 );
• d) folding the weld seam region ( 17 ) of the film ( 10 ) onto the relevant peripheral, in particular lateral surface ( 16 ) of the core ( 3 );
• e) almost tension-free and draft-free folding of the areas ( 26 , 51 ) of the cut of the gas-tight film ( 10 ) projecting over the core ( 3 ) on both sides of the covered core circumference ( 25 ), in particular at the front ( 24 ), covering and covering the entire area on the remaining core surface (s) ( 24 ), in particular on the end face;
• f) sealing or welding the folded-together film regions ( 27 , 56 ) on at least one end, in particular end face ( 24 ) of the core ( 3 );
• g) evacuating ( 58 ) the film-coated core ( 3 );
• h) complete sealing ( 50 ) or welding of all remaining openings ( 22 ) of the film ( 10 ) under vacuum ( 58 ).

2. The method according to claim 1, characterized in that the core ( 3 ) is pressed from a powder. 3. The method according to claim 1, characterized in that the core ( 3 ) made of a plastic, preferably open-pore polyurethane or extruded polystyrene, is foamed. 4. The method according to any one of the preceding claims, characterized in that the core ( 3 ) of the heat insulating body ( 2 ) with an air-permeable, sheet-shaped material (z. B. Nonwoven fabric, filter paper) ( 8 ) is wrapped, which during evacuation ( 58 ) holds loose particles of the core ( 3 ). 5. The method according to any one of the preceding claims, characterized in that the core ( 3 ) before covering ( 9 ) by means of the gas-tight film ( 10 ) is covered by a thin plate made of cardboard, for example. 6. The method according to any one of the preceding claims, characterized in that the core ( 3 ) before the covering ( 9 ) by means of the gas-tight film ( 10 ) is provided with an edge protection made of a comparatively hard material. 7. The method according to any one of the preceding claims, characterized in that the gas-tight film ( 10 ) is cut off from a long film web ( 11 ), the width of which is at least twice the minimum width of a welding web greater than the distance b between two opposite end, in particular End faces ( 24 ) of the preformed core ( 3 ). 8. The method according to any one of the preceding claims, characterized in that the core ( 3 ), the fleece ( 8 ) and / or the film ( 10 ) is dried before sealing ( 9 ). 9. The method according to any one of the preceding claims, characterized in that in the context of the end, in particular frontal folding, the film regions ( 40 ) adjoining the shorter end, in particular end edges ( 36 ) are first folded inwards. 10. The method according to any one of the preceding claims, characterized in that the end, in particular the front, folded and sealed film areas ( 27 , 56 ) are folded up to the surface ( 24 ) of the core ( 3 ). 11. The method according to any one of the preceding claims, characterized in that the weld seams ( 20 , 21 , 50 ) folded over onto the surface (s) ( 16 , 24 ) of the core ( 3 ) are adhesively fixed to the film layer ( 10 ) located underneath , 12. The method according to any one of the preceding claims, characterized in that the heat insulation body ( 2 ) is evacuated ( 58 ) to a partial vacuum below 100 hPa, preferably below 10 hPa, in particular below 1 hPa. 13. Evenly bordered, generally prismatic, preferably cuboid, in particular plate-shaped, of a gas-tight film ( 10 ) enveloped and evacuated thermal insulation body ( 2 ), characterized in that a stable, pre-formed from a porous, in particular open-pore material core ( 3 ) from a single blank sheet of the gas-tight film ( 10 ) is completely encased. 14. Thermal insulation body according to claim 13, characterized in that the core ( 3 ) is pressed from a powder, for example. Fumed silica. 15. Thermal insulation body according to claim 13 or 14, characterized in that the core ( 3 ) is foamed from a plastic, for example. Poystyrene or polyurethane. 16. Thermal insulation body according to one of claims 13 to 15, characterized in that all edges ( 28 , 35 , 36 ) of the core ( 3 ) are sharp-edged with edge radii of less than 1 to 2 mm. 17. Thermal insulation body according to one of claims 13 to 16, characterized in that all circumferential, in particular jacket sides ( 16 , 25 ) of the core ( 3 ) are formed exclusively with outer edges ( 28 , 35 , 36 ), ie edges with a convex curvature , 18. Thermal insulation body according to one of claims 13 to 17, characterized in that the core ( 3 ) is designed such that the sum of the surface angles (β ₁ , β ₂ , β ₃ , γ ₁ , γ ₂ , γ ₃ ) of each two corners ( 29 , 38 ) adjacent to the same end or end face ( 24 ) is 540 °:
β ₁ + β ₂ + β ₃ + γ ₁ + γ ₂ + γ ₃ = 540 °. 19. Thermal insulation body according to one of claims 13 to 18, characterized in that the core ( 3 ) is designed such that the sum of the surface angles (β ₁ , β ₂ , β ₃ , γ ₁ , γ ₂ , γ ₃ ) of each at the same corner ( 29 ; 38 ) meeting surfaces is 270 °:
β ₁ + β ₂ + β ₃ = γ ₁ + γ ₂ + γ ₃ = 270 °. 20. Thermal insulation body according to one of claims 13 to 19, characterized in that the core ( 3 ) at opposite areas has congruent or complementary side surfaces ( 24 ) which allow a seamless jointing of several thermal insulation bodies ( 2 ). 21. Thermal insulation body according to one of claims 13 to 20, characterized in that the core ( 3 ) is plate-shaped, the distance between the plate base surfaces ( 16 , 37 ) is substantially constant. 22. Thermal insulation body according to one of claims 13 to 21, characterized in that the plate base surfaces ( 16 , 37 ) are rectangular. 23. Thermal insulation body according to claim 22, characterized in that edges ( 28 ; 36 ) between an end face ( 24 ) and the adjacent base plate side ( 16 , 37 ) of the core ( 3 ) are rectangular. 24. Thermal insulation body according to one of claims 13 to 23, characterized in that the melting point of the core ( 3 ) is above the melting point of the sealable part of the film ( 10 ). 25. Thermal insulation body according to one of claims 13 to 24, characterized in that the film ( 10 ) is designed as a composite film with a lower melting coating on its inside. 26. Thermal insulation body according to one of claims 13 to 25, characterized in that the film ( 10 ) in its intermediate layers and / or on its outside has a gas-tight metallization. 27. Thermal insulation body according to one of claims 13 to 26, characterized in that the film blank ( 10 ) is rectangular. 28. Thermal insulation body according to one of claims 13 to 27, characterized in that the film ( 10 ) drawn tightly around the core ( 3 ) is sealed along a circumferential, in particular lateral surface ( 16 , 37 ) of the core ( 3 ). 29. Thermal insulation body according to claim 28, characterized in that the circumferential, in particular jacket-side weld region ( 17 ) of the film ( 10 ) is folded up onto the relevant jacket surface ( 16 ) of the core ( 3 ). 30. Thermal insulation body according to one of claims 13 to 29, characterized in that the width B of the end face, in particular the face side, of the plate base area ( 16 , 37 ) of the end face ( 24 ) extending inclinedly between the plate base areas ( 16 , 37 ) Core ( 3 ) protruding area ( 26 , 51 ) of the cut of the gas-tight film ( 10 ) on at least one jacket end edge ( 28 ) corresponds to the following dimensions:
s + [(h / 2). (1 / sin β ₂ ). (1 + cos β ₂ )] ≦ B ≦ h / sin β ₂ ,
in which:
h = distance between the parallel plate bases
s = width of the welding lug
β ₂ = edge angle at the relevant jacket-forehead edge. 31. Thermal insulation body according to one of claims 13 to 30, characterized in that the end, in particular the end over the core ( 3 ) projecting areas ( 26 , 51 ) of the cut of the gas-tight film ( 10 ) while covering the and full-surface concerns of the end, in particular the front surface (s) ( 24 ) of the preformed core ( 3 ) are folded together without stress. 32. Thermal insulation body according to one of claims 13 to 31, characterized in that the weld seams ( 50 ) in the region of the end faces, in particular end faces ( 24 ), run approximately parallel to one another. 33. Thermal insulation body according to claim 32, characterized in that the weld seams ( 50 ) in the area of the end, in particular end faces ( 24 ) run approximately parallel to that peripheral, in particular jacket surface ( 16 ) on which the circumferential, in particular jacket side Weld seam ( 20 , 21 ) is located. 34. Thermal insulation body according to claim 33, characterized in that the distance of the circumferential, in particular casing-side weld seam ( 20 , 21 ) from the adjacent circumferential, in particular casing edges ( 35 ) is spaced such that they are outside the region of the end overlaps ( 40 ). 35. Thermal insulation body according to one of claims 13 to 34, characterized in that in the region of a corner ( 29 , 38 ) of the preformed core ( 3 ) five folded edges ( 32-34 ) converge. 36. Thermal insulation body according to claim 35, characterized in that one of the folded edges ( 34 ) encloses an angle between 30 ° and 60 °, preferably of approximately 45 ° with at least one, preferably two adjacent folded edge (s) ( 32 , 33 ). 37. Thermal insulation body according to one of claims 13 to 36, characterized in that below an end weld flap ( 27 , 56 ) two folding edges ( 34 ) extending from two adjacent corners ( 29 , 38 ) outside the relevant end edge, in particular end edge ( 36 ) meet ( 45 ). 38. Thermal insulation body according to claim 37, characterized in that a total of five folded edges ( 33 , 44 , 49 ) converge at the meeting point ( 45 ) lying outside the relevant end edge, in particular end edge ( 36 ). 39. Thermal insulation body according to one of claims 13 to 38, characterized in that the folded edges ( 32-34 , 44 , 49 ) at the end, in particular end faces ( 24 ) run such that film sections ( 10 ) always with two inner surfaces or with two outer surfaces lie against each other. 40. Thermal insulation body according to one of claims 13 to 39, characterized in that the film regions ( 42 ) adjoining the shorter end edges, in particular end edges ( 36 ), are folded down to the inside. 41. Thermal insulation body according to one of claims 13 to 40, characterized in that the folded-up film areas ( 27 , 56 ) are sealed at the end, in particular end faces ( 24 ) of the core ( 3 ). 42. Thermal insulation body according to claim 41, characterized in that the end, in particular end, folded and sealed film areas ( 27 , 56 ) are folded up to the relevant end, in particular end face ( 24 ). 43. Thermal insulation body according to one of claims 13 to 42, characterized in that the weld seams ( 20 , 21 , 50 ) folded onto the surface (s) ( 16 , 24 ) of the core ( 3 ) are adhesively attached to the film layer ( 10 ) underneath. are set. 44. Thermal insulation body according to one of claims 13 to 43, characterized in that the jacket-side weld seam is formed from several sections ( 20 , 21 , 63 , 65 ) which continue, overlap and / or overlap. 45. Thermal insulation body according to one of claims 13 to 44, characterized in that the partial vacuum in the evacuated thermal insulation body ( 2 ) is below 100 hPa, preferably below 10 hPa, in particular below 1 hPa. 46. Thermal insulation body according to one of claims 13 to 45, characterized characterized that its surface with a profiling, e.g. Corrugation. 47. Thermal insulation body according to one of claims 13 to 46, characterized in that at least one extension of the film covering ( 10 ) is provided, which allows welding to a corresponding extension of an adjacent heat insulation body ( 2 ).