EP2852801A1

EP2852801A1 - Thermal insulation body and method for the production thereof

Info

Publication number: EP2852801A1
Application number: EP13725339.9A
Authority: EP
Inventors: Bodo Benitsch; Sinisa Milovukovic; Robert Hauser
Original assignee: SGL Carbon SE
Current assignee: SGL Carbon SE
Priority date: 2012-05-23
Filing date: 2013-05-23
Publication date: 2015-04-01
Also published as: DE102012208596A1; KR20150013848A; CN104334992B; CN104334992A; JP5889481B2; JP2015523532A; SG11201407712RA; WO2013174898A1; US20150079312A1

Abstract

A thermal insulation body consisting of a material comprising carbonized fibres and/or graphitized fibres, in particular for lining a high-temperature furnace, is assembled from at least two individual parts, wherein at least two assembled individual parts each have at least one connecting element and the connecting elements of the at least two assembled individual parts interengage positively to form an undercut.

Description

Heat insulating body and method for its production

The present invention relates to a heat insulating body made of a carbonized fibers and / or graphitized fibers comprising material, in particular hard felt, in particular for lining a high temperature furnace, wherein the heat insulation body is assembled from at least two individual parts. High-temperature processes, which occur, for example, at over 800 ° C under an inert atmosphere, place high thermal and mechanical demands on the insulating materials used. As a material for insulating bodies, which e.g. lining an interior of a high-temperature furnace and thus separate the heating chamber from the cooled outer wall, often carbonized and possibly graphitized felts are used. Compared to the production of a heat insulating body in one piece, which can be done for example by winding unhardened, resin impregnated felt layers on a mandrel and then curing of the felt material, the production of a heat insulating body of several items offers the advantage of a lower raw material blend and a more efficient high temperature aftertreatment of the felt material.

EP 1 852 252 B1 discloses a method for producing high-temperature-resistant insulating bodies, in which, inter alia, a plurality of curved segments are formed from a material based on a graphite expanded material compressed to a density between 0.02 and 0.3 g / cm ³ hollow cylindrical component are assembled. The cohesion of the individual segments is ensured by a carbonizable binder, which areal anisotropic Contains graphite particles. On the inner surface of the hollow cylindrical insulating body, a graphite foil is further arranged.

WO 201 1/106580 A2 discloses an insulator made of a carbon fiber material for a reactor, which is composed of a plurality of plate-like individual components. The individual components may be coupled by "tongue-and-groove" connectors using further connectors.

However, a problem with the known multi-piece heat insulating bodies is that at the junctions between adjacent individual parts, i. at the joining surfaces, the mechanical and thermal properties of the component can not be maintained. This is true even if the items are glued together or interlock. Thus, there is the danger that heat transfer losses occur due to the transition points and the mechanical stability is weakened, which is fundamentally undesirable. In order to prevent corresponding heat conduction losses and to maintain the mechanical stability, additional elements made of graphite, of carbon fiber-based composite materials or of metal may be provided on the joining surfaces. However, this leads to accumulations of material and / or an accumulation of different materials, which is associated with a high cost and correspondingly increased manufacturing and storage costs. In addition, due to the structural separation of mechanical stability and thermal resistance, the material properties of the individual components are not optimally exploited locally.

It is therefore an object of the invention to provide a simple and inexpensive to produce from several items heat insulation body, which also in the transition areas between the various items a Reliable insulation and a sufficiently high mechanical stability.

The object is achieved by a heat insulating body with the features of claim 1 and in particular by a heat insulating body comprising carbonized fibers and / or graphitized fibers material, in particular for lining a high temperature furnace, wherein the heat insulation body is assembled from at least two individual parts, wherein at least two assembled individual parts each have at least one connecting element and the connecting elements of the at least two assembled individual parts with the formation of an undercut at least form-fitting or even interlocking positive and non-positive.

According to the invention, in each case at least two connecting elements are provided on at least two assembled individual parts-that is, at least at individual sections of the joining surfaces on which the individual parts are joined together-connecting elements are provided which engage one another at least in a form-fitting manner to form an undercut. Due to the undercut, the items are held together securely on the mating joining surfaces - preferably in 5 of the 6 mutually orthogonal spatial directions - and can also under the conditions of use in one

High-temperature furnace can no longer be separated. An elaborate bonding of the items can thus be dispensed with. The movement in the 6th spatial direction is preferably inhibited via a non-positive connection. A provision of additional reinforcing elements, such as steel strips, so can be omitted, whereby the manufacturing and storage costs can be reduced considerably. Another particular advantage of the invention is that the undercut forms a barrier against heat conduction losses at the joint surfaces and thus additional insulating components can be saved to cover the joints. Because no accumulation of different materials In addition, discontinuities with regard to the relevant material properties, such as thermal conductivity, density, compressive strength or flexural strength, can be reliably avoided. Therefore, the invention enables a simple to manufacture, self-supporting and homogeneous with respect to the relevant material parameters heat insulation body, which can be easily adapted to different application specifications, eg to different furnace geometries due to the structure of individual parts.

Preferably, the individual parts are held together at least in the form-fitting manner at the contacting joining surfaces in 5 of the 6 mutually orthogonal spatial directions. A movement in the sixth spatial direction is preferably inhibited by a purely non-positive connection.

In order to achieve a particularly high stability of the heat insulation body, it is preferred that all individual parts of which the heat insulation body is joined together each have at least one connecting element, wherein the connecting elements of at least two assembled individual parts interlock to form an undercut.

Preferably, the individual parts are joined together exclusively by means of the connecting elements, ie no gluing, clamping or the like are used. As a result, foreign materials are avoided in the heat insulating body, which can lead to undesirable discontinuities of the material properties and heat conduction losses. Preferably, the connecting elements of the at least two assembled individual parts engage in one another in a non-positive manner while forming a press fit. The interference fit, in addition to the positive connection and a frictional connection is created, which further increases the stability of the connection against unintentional disconnection. A sol- Combination of positive and non-positive connection results in a joint, which ensures a reliable and permanent cohesion of the items in question even with high thermal and mechanical stress. The connecting elements of the at least two assembled individual parts are molded directly to the individual parts of the heat insulation body according to a preferred embodiment of the invention. That is, the connecting elements each form an integral part of the relevant item of the heat insulation body. Thus, the costly attachment of additional components can be avoided. In addition, the strength of the joint is particularly high when there is a material connection between the individual parts and the associated connecting elements.

According to a particularly preferred embodiment of the present invention, at least one of the individual parts and preferably all individual parts, including the connecting elements, are made of a homogeneous felt composed of carbonized fibers and / or graphitized fibers. Such felts have a high temperature resistance and at the same time a high mechanical strength, so that they are particularly suitable as a material for thermal insulation in high-temperature environments.

Furthermore, it is preferred that at least one of the individual parts and preferably all individual parts, including the connecting elements, each consist of the same material, which preferably a, composed of carbonized fibers and / or graphitized fibers, in particular impregnated, soft felt or a carbonized fibers and / or graphitized fibers composite hard felt is, is / is made. This avoids unwanted discontinuities in thermal conductivity or strength and ensures that via the contact points between two assembled items no unwanted heat loss occurs.

According to another preferred embodiment of the present invention is at least one of the individual parts and are preferably all items of felt with a density between 0.01 and 0.50 g / cm ³ , preferably between 0.10 and

0.25 g / cm ³ and more preferably between 0.13 and 0.20 g / cm ³ made. Felts with such properties have proven to be particularly favorable for the production of heat insulating bodies of the type described above. According to yet another preferred embodiment of the present invention is at least one of the individual parts and are preferably all items made of felt with a thickness between 5 and 500 mm, preferably between 20 and 250 mm and more preferably between 40 and 120 mm. Felts with such properties have proven to be particularly favorable for the production of Wärmeisola- tion bodies of the type described above.

Furthermore, particularly good results in terms of stability and insulating effect are achieved if at least one of the individual parts and preferably all individual parts is made of felt, which is composed of carbonized fibers and / or graphitized fibers having a length of less than 10,000 mm, preferably less than 1, 000 mm and more preferably less than 100 mm.

In a further development of the inventive concept, it is proposed that at least one of the individual parts and preferably all individual parts is made of felt which contains a carbon-containing binder. In principle, all known binders can be used for this purpose, in particular with binders good results being obtained, which are selected from the group consisting of phenolic resins, pitches, furan resins, phenyl esters, Epoxy resins and any mixtures of two or more of the aforementioned compounds. Felts with such binders are particularly favorable materials for insulation.

Furthermore, an advantageous embodiment of the present invention provides that at least one of the individual parts and preferably all individual parts is made of felt, which has a measured according to DIN 51936 thermal conductivity at 2000 ° C of at most 1, 5 W / (mK) and preferred of at most 0.8 W / (mK). Thus, heat conduction losses in high-temperature systems are sufficiently prevented.

According to another preferred embodiment of the present invention, at least one of the individual parts and preferably all individual parts of the heat insulation body are made of felt, which has a compressive strength measured according to DIN EN 658-3 and / or one according to DIN EN 658-2 and the

DIN 51910 measured bending strength of at least 0.2 MPa, preferably of at least 0.5 MPa and more preferably of at least 0.8 MPa.

Furthermore, it has proved to be advantageous in the context of the present invention to form the heat insulation body as a hollow profile and preferably as a hollow cylinder. Such a hollow profile is particularly suitable for lining the heating chamber of a high-temperature furnace. In this case, the heating chamber is protected by a arranged on its inner walls hollow profile-like heat insulation body against heat loss through the inner walls. High temperature furnaces often have a cylindrical heating chamber which is easily inserted through a size-matching heat-insulating hollow cylinder by insertion of the hollow cylinder, e.g. via an upper opening, can be isolated.

Preferably, the items are flat and form a wall of the hollow profile, wherein the undercut each transverse to a surface normal the wall is effective. By acting across the surface normal undercut a "tearing" of the wall is reliably avoided. Particularly preferably, the undercut is effective only transversely to the surface normal of the wall. This opens up the possibility of merging or assembling the respective individual parts in a direction in which the undercut is not effective, whereby the assembly is simplified.

It is further proposed in a further development of the concept of the invention to join at least two of the individual parts and preferably all individual parts of the heat insulating body by means of form-fitting dovetail connections. Dovetail joints can develop a force-enhancing wedge effect due to the sloping flanks of a tine and therefore offer a comparatively high strength. In particular, they can transmit both lateral forces and tensile forces.

The opening angle of the dovetail connections may in each case be between 5 ° and 85 °, preferably between 15 ° and 75 ° and particularly preferably between 30 ° and 60 °. Such opening angles have proven to be particularly favorable in terms of connection strength.

According to another embodiment of the present invention, the connecting elements are designed as elongated grooves and in these matching springs, which each have mutually inclined flanks to form the undercut. By providing inclined flanks, a "tongue-and-groove" connection suitable only for absorbing transverse forces can be expanded to a dovetail-like connection with an undercut, which absorbs both lateral forces and tensile forces. In a further development of the concept of the invention, it is proposed that the angle between two opposite inclined flanks of a spring or a groove be between 15 ° and 30 ° and particularly preferably between 20 ° and 24 °. This makes it possible to create particularly stable connections. Furthermore, the ratio of the width of a spring to the width of the associated item is preferably between 1: 1, 5 and 1: 5 and more preferably between 1: 2 and 1: 3. This embodiment is particularly favorable in terms of the thermal and mechanical properties of the manufactured heat insulation body. A further embodiment of the present invention provides that the grooves and the springs seen in the longitudinal direction in sections do not form an undercut and preferably also no press fit. The individual parts can then be brought together offset from one another in such a way that the undercuts are to a certain extent bypassed and take effect only when the individual parts are brought back together in the assembled state. As a result, a particularly simple assembly is possible, because the paths that have to cover the two parts to be assembled relative to each other, are considerably shortened. Particularly advantageous is the sectionwise omission of the undercut in the case of an additional use of a press fit, by means of which force closure an additional inhibiting effect is produced. Here, the shortened paths also cause a reduced abrasion within the press fit.

The grooves and the springs preferably define at regular intervals areas without undercut and preferably without interference fit. For example, all 150 mm to 250 mm regions can be provided without an undercut and preferably also without an interference fit along an individual part side. The heat insulation body may define a longitudinal axis and be composed of a plurality of rows of individual parts arranged one behind the other along the longitudinal axis, wherein the joining surfaces of two adjacent rows are offset relative to one another with respect to the longitudinal axis, and preferably offset by half an individual part length. This results in a stable association of the items similar to a masonry association with staggered stones. In principle, any length of hollow sections or pipes can be constructed in this way.

The individual parts of a row are preferably joined together without forming an undercut. This facilitates the merging of the items during assembly.

For reasons of easier manufacture and handling and to increase the mechanical stability, it has proven advantageous to make the edges rounded between projecting and recessed portions of each of the connecting elements, wherein preferably the radius of curvature of the rounded edges between 1 mm and 10 mm and preferably between 3 mm and 7 mm. Furthermore, it is preferred that the individual parts are formed as plates, wherein the connecting elements are provided at least on two opposite narrow sides and preferably on all four narrow sides of each plate. The provision of connecting elements exclusively on two opposite narrow sides of each plate in this case allows a particularly simple production.

According to another preferred embodiment of the present invention, the plates are flat, with the joining surfaces extending at right angles to the flat sides of the plates. This comes especially to building up extensive wall-like structures, as they are often required in thermal insulation bodies.

According to an alternative embodiment of the invention, the plates are also flat, but the joining surfaces extend in a plane which with the flat sides of the plates an angle between 1 ° and 85 °, preferably between

30 ° and 75 °, and more preferably 45 °. As a result, for example, hollow profiles with a polygonal cross-section can be constructed in a simple manner. By such hollow profiles with a polygonal cross-section especially more complex, curved profile structures can be approximated, so as to exploit the fact that flat items are easier to manufacture and are more flexible than curved items.

The joining surfaces of the flat-shaped individual parts can also form at least one step in the direction of the surface normal. By such a stepped execution of the joining surface, on which two individual parts are joined together, the insulating effect and the strength of the Wärmeisolierkörpers can be further increased.

In this case, an embodiment has proven to be particularly favorable, in which the joining surfaces, in each case in the direction of the surface normal, are divided by the stage or by the plurality of stages into equally wide joining zones.

It is also possible to provide no connecting elements in at least one of the joining zones of a specific joining surface. In this case, it is preferable that, viewed in the direction of the surface normal, the width of the joining zone or the plurality of joining zones in which connecting elements are provided, to the width of the joining zone or the plurality of joining zones, in which no connecting elements are provided, at least 1: 1 and preferably 2: 1 or 3: 1. Thus, for example, has the toothed joining zone based on the component thickness preferably a greater extent than the untoothed joint zone, so that a sufficient stability is ensured.

Another object of the present invention is a method for producing a heat insulating body and in particular a Wärmeisolations- body of the type described above. According to the invention, at least two individual parts of a material comprising carbonized fibers and / or graphitized fibers provided, at least two at least a connecting element for a positive engagement to form an undercut are provided. The individual parts are then assembled to form a heat insulation body by the connecting elements are inserted into each other. The interlocking of the individual parts forms a positive connection with an undercut, which reliably prevents inadvertent separation of the two individual parts during the later use of the heat insulation body. The connection can optionally be supported with a non-positive press fit.

Preferably, the connecting elements are produced by machining the surface of individual blanks from a homogeneous felt material, preferably from, in particular impregnated, soft felt or hard felt. The processing can be done for example by means of grinding, milling, sawing, drilling or cutting. In this type of procedure, it is not necessary to make separate fasteners and attach to the items, so that the production of the heat insulating body is simplified. In addition, to a certain extent automatically results in avoiding foreign materials and thus a particularly uniform heat conduction behavior of the heat insulation body.

In providing the individual parts to the connecting elements, an excess is preferably provided for a press fit, which is preferably at most 0.5 mm, more preferably at most 0.25 mm, and most preferably between 0.01 mm and 0.2 mm. The press fit creates, in addition to the existing positive connection, a frictional connection which not only increases the mechanical strength but also ensures a uniform thermal conductivity in the area of the joining surface.

In a further development of the inventive concept, it is proposed to slidably assemble two individual parts together along a first joining direction during joining and then to displace them along a second joining direction different from the first joining direction in such a way that an undercut effective along the first joining direction forms on the connecting elements. This facilitates the assembly of the heat insulation body, since the merging of the items can be done without excessive force. In the following, the invention will be further described with reference to an illustrative, but not limiting example, with reference to the drawings.

Fig. 1A is a perspective view of a heat insulating body according to a first embodiment of the invention.

Fig. 1B is a side view of the heat insulating body of Fig. 1 A.

FIG. 2 is a perspective view of a heat insulating body according to a second embodiment of the invention. FIG.

3 is a perspective view of a heat insulating body according to a third embodiment of the invention. 4A is a perspective view of an individual part of a heat insulating body according to a fourth embodiment of the invention.

Fig. 4B shows a plurality of assembled items as shown in FIG. 4A. Fig. 5A is a perspective view of an individual part of a heat insulating body according to a fifth embodiment of the invention.

Fig. 5B shows several assembled items as shown in FIG. 5A. According to Fig. 1 A and 1 B, a hollow cylindrical, a cylinder longitudinal axis L exhibiting heat insulating body 1 1 is used to minimize heat loss in a high temperature system. The heat insulating body 1 1 is made of several individual parts 13 each made of a hard felt based on carbonized fibers. For example, the hard felt has a density of 0.2 g / cm ³ , a compressive strength of 1 MPa, a bending strength of 1 MPa and a thermal conductivity in the radial direction at 2000 ° C of 0.8 W / (mK).

The illustrated in Fig. 1 A and 1 B first embodiment of the invention provides that at the radial end faces 14 of the individual parts or cylinder segments 13 connecting elements 17 are provided in the form of dovetail teeth, which interlock positively to form an undercut 19. On the other hand, no dovetail teeth 17 are provided on the axial end faces 16 of the cylinder segments.

For producing the dovetail teeth 17, the cylinder segments 13 are preferably mechanically worked after hardening and thermal treatment, such as carbonizing and optionally graphitizing, the felt material at the corresponding opposite end faces 14. The dovetail teeth 17 are therefore attached directly to the cylinder segments 13. shaped. During machining, a geometric oversize of 0.01 mm to 0.2 mm is provided on the corresponding surfaces. After completion of the machining, the cylinder segments 13 are brought together in a direction perpendicular to the cylinder longitudinal axis L extending joining direction F1, wherein the dovetail teeth 17 engage. In this case, the inclined flanks 21 of the dovetail teeth 17 form an undercut 19 that is effective in the circumferential direction and reliably prevents the cylinder segments 13 from loosening. Due to the oversize provided in the processing, an interference fit is additionally produced, which interacts with the undercut 19. It has surprisingly been found that such a joint has the same thermal conductivity as the remaining felt material of the cylinder segments 13. Thus, the combination of positive and non-positive connection creates a particularly reliable joining, which even under the high thermal and mechanical requirements in a Hochtemperaturan- ensure a consistently high stability of the heat insulation body 1 1 ensured. The joint is also made of the same material as the joint

As such, undesirable discontinuities in the properties of the material, e.g. the thermal conductivity or flexural strength, avoided. Due to the one-piece design of cylinder segment 13 and dovetail 17, the manufacturing and storage costs are also reduced. In addition, the expansion of the joining surfaces 15 is kept low.

The hollow cylindrical heat insulating body 1 1 is as shown in FIGS. 1 A and 1 B composed of several rows 23 along the cylinder longitudinal axis L successively arranged cylinder segments 13, the joining surfaces 15 of two adjacent rows 23 are axially offset by half a segment length , As a result, tube-like heat insulation bodies 1 1 can be constructed in any length in any simple manner. The dovetail teeth 17 preferably have an opening angle between 30 ° and 60 °. Furthermore, a uniform distribution of the dovetail teeth 17 on the two cylinder segments concerned 13 has proved to be advantageous. The edges 25 between projecting and recessed portions of the dovetail teeth 17 are rounded with a radius of curvature of 5 mm, which is not visible in the illustrations of Figs. 1A and 1B. With the dovetail teeth 17 described above, instead of cylinder segments 13, it is also possible to connect plate-like planar individual parts 13 'with one another, so as to obtain a plate-like planar heat insulation body 1 1'. Two plane parts 13 'interconnected in this way are shown in FIG. Another difference from the embodiment according to FIGS. 1A and 1B is that the joining surfaces 15 'are of stepped design, ie are divided by a step 27 into two equally wide joining zones 28, 29. In the embodiment shown in FIG. 2, dovetail teeth 17 are provided in only one of the two joining zones 28, 29. Alternatively, swallows-tail toothing 17 could also be provided in both joining zones 28, 29.

Should the respective application specify a more complex geometry, it is also possible to combine plane individual parts 13 'according to FIG. 2 with cylinder segments 13 according to FIGS. 1A and 1B. Furthermore, even complex shaped, arbitrarily curved individual parts can be provided and combined with cylinder segments 13 or flat individual parts 13 'in a suitable manner.

Fig. 3 shows an embodiment of the invention in which instead of dovetail joints 17 tongue and groove joints 17 'are provided. Specifically, elongated, over the entire joint surface 15 extending grooves 30 and 31 are provided in these matching springs, wherein the edges 21 of the grooves 30 and the springs 31 are each inclined to form an undercut 19 according to an opening angle of 20 ° to 24 ° to each other , The undercut 19 formed thereby prevents, as in the embodiment according to FIG. 2, a separation of the flat individual parts 13 '. When making the grooves 30 and the springs 31, an oversize of 0.01 mm to 0.2 mm is provided, resulting in a press fit when merging the flat items 13 'along the joining direction F1. This complements the undercut 19 to a stable and heat-insulating joint. Preferably, the ratio of the width of a spring 31 to the thickness of the associated planar member 13 'is between 1: 2 and 1: 3.

The undercut 19 is interrupted at regular intervals, i. the grooves 30 and the springs 31 alternately have regions 33 with undercuts and regions 34 without undercuts. During assembly, therefore, in each case two individual parts 13 'can be arranged offset from one another such that two regions 34 meet without an undercut. In this arrangement, a sliding merging of the individual parts 13 'along a first joining direction F1 is possible, wherein the joining surfaces 15 initially come to rest loosely on each other. By subsequent parallel displacement of the individual parts 13 'along a perpendicular to the first joining direction F1 extending second joining direction F2 reach the undercuts 19 into engagement, so that in turn results in a combination of positive and non-positive connection between the relevant items 13'.

In the further embodiment of the invention shown in FIGS. 4A and 4B, as in the embodiment according to FIG. 3, oblong grooves 30 and associated springs 31 are provided on opposite end faces of a respective flat individual part 13 '. Again, the undercut 19 is in regular Interrupted intervals, ie the grooves 30 and the springs 31 have alternately areas 33 with undercut and areas 34 without undercut.

As can be seen in FIG. 4A, those joining surfaces 15 in which a groove 30 is formed extend in a plane pointing at right angles to the plane of the plate. Those joining surfaces 15 which have a spring 31, however, enclose an angle between 1 ° and 85 ° with the plane of the plate. As a result, it is easy to build hollow profiles from flat individual parts 13 ', as illustrated in FIG. 4B. As low has in such a production of closed profiles, such as pipes and cylinders, an even number of items 13 'exposed. As a result, in particular a symmetrical extension of the same mechanical load capacity is possible, on the one hand, on the other hand, two half-shells of individual elements can be initially constructed, which are connected together in a final joining process by moving along a plane.

In the further embodiment of the present invention shown in FIGS. 5A and 5B, as in the embodiments according to FIGS. 3, 4A and 4B, oblong grooves 30 and associated springs 31 are provided on opposite end faces of a respective individual part 13 '. Again, the undercut 19 is interrupted at regular intervals, ie the grooves 30 and the springs 31 have alternately areas 33 with undercut and areas 34 without undercut. However, in this embodiment, the individual parts 13 have a cylindrical curvature, which makes it possible to assemble several individual parts 13 into a hollow-cylindrical component as shown in FIG. 5B. LIST OF REFERENCES:, 1 1 'heat insulation body

, 13 'Item / Cylinder segment

radial end face, 15 'joining surface

axial end face, 17 'connecting element

undercut

flank

line

edge

step

first joint zone second joint zone

groove

feather

Area with undercut

Area without undercut

cylinder longitudinal axis

first joining direction

second joining direction

Claims

claims:

Heat insulation body (11, 11 ') of a material comprising carbonized fibers and / or graphitized fibers, in particular for lining a high temperature furnace, the heat insulation body (11, 11') being composed of at least two individual parts (13, 13 '), at least two assembled individual parts (13, 13 ') each have at least one connecting element (17, 17') and the connecting elements (17, 17 ') of the at least two assembled individual parts (13, 13') interlocking form-fitting manner to form an undercut (19).

Heat insulating body according to claim 1,

By doing so, that is

the connecting elements (17, 17 ') of the at least two assembled individual parts (13, 13') in addition engage frictionally with the formation of a press fit.

Heat insulating body according to claim 1 or 2,

By doing so, that is

the connecting elements (17, 17 ') of the at least two assembled individual parts (13, 13') are formed directly on the individual parts (13, 13 ') of the heat insulation body (11, 11').

Heat insulating body according to at least one of the preceding claims,

By doing so, that is

at least one of the individual parts (13, 13 ') and preferably all individual parts (13, 13') including the connecting elements (17, 17 ') from a homogeneous NEN and made of carbonized fibers and / or graphitized fibers felt is / are made.

Heat insulating body according to claim 4,

By doing so, that is

at least one of the individual parts (13, 13 ') and preferably all individual parts (13, 13') including the connecting elements (17, 17 ') each of the same material, which preferably a composite of carbonized fibers and / or graphitized fibers, in particular impregnated , Soft felt or a hard felt composed of carbonized fibers and / or graphitized fibers is / is made.

Heat insulating body according to at least one of the preceding claims,

By doing so, that is

the heat insulation body (11) is designed as a hollow profile and preferably as a hollow cylinder.

Heat insulating body according to claim 6,

By doing so, that is

the items (13, 13 ') are formed flat and a wall of the

Form hollow profiles, wherein the undercut (19) each transverse to a

Surface normal of the wall is effective.

Heat insulating body according to at least one of the preceding claims,

By doing so, that is

at least two of the individual parts (13, 13 ') and preferably all the individual parts (13, 13')

13 ') are joined together by means of dovetail connections.

9. heat insulation body according to at least one of the preceding claims,

By doing so, that is

the connecting elements are designed as elongated grooves (30) and springs (31) fitting in them, which have mutually inclined flanks (21) for forming the undercut (19).

10. heat insulation body according to claim 9,

By doing so, that is

the grooves (30) and the springs (31), seen in the longitudinal direction, do not form part of an undercut and preferably also no press fit.

11. Heat insulating body according to at least one of the preceding claims,

By doing so, that is

the individual parts (13, 13 ') are formed as plates, wherein the connecting elements (17, 17') are provided at least on two opposite narrow sides (14) and preferably on all four narrow sides of each plate.

12. Heat insulating body according to at least one of the preceding claims,

By doing so, that is

form the joining surfaces (15, 15 ') of the flat-shaped individual parts (13, 13') seen in the direction of the surface normal at least one step (27). Method for producing a heat-insulating body (11, 11 '), in particular a heat-insulating body according to at least one of the preceding claims, comprising the following steps:

Providing at least two individual parts (13, 13 ') of a material comprising carbonized fibers and / or graphitized fibers, wherein at least two connecting parts (13, 13') each have at least one connecting element (17, 17 ') for a positive engagement under Training an undercut (19) are provided, and

Assembling of the individual parts (13, 13 ') to a heat insulation body (11, 11') by the connecting elements (17, 17 ') are plugged into one another.

Method according to claim 13,

By doing so, that is

the connecting elements (17, 17 ') by machining the surface of

Single-part blanks of a homogeneous felt material, preferably from, in particular impregnated, soft felt or hard felt, are produced.

Method according to claim 13 or 14,

By doing so, that is

in providing the individual parts (13, 13 ') on the connecting elements (17, 17') an oversize is provided for a press fit, which is preferably at most 0.5 mm, more preferably at most 0.25 mm and most preferably between 0, 01 mm and 0.2 mm.