Electrically decoupled high-temperature thermal insulation

1 . An insulation element for thermally insulating an inductively heatable high-temperature treatment zone,

wherein a wall of the insulation element comprises a flat material having a specific electrical resistance ρF of 10 −5 to 10 −1 Ωm,

wherein the flat material surrounds a cavity extending through the insulation element and includes at least one break,

wherein the at least one break has a specific electrical resistance ρU≥100×ρF, and

wherein each break extends from an outer surface of the flat material and into the flat material but does not create a break in the flat material across the entire flat material cross section.

2 . The insulation element according to claim 1 , wherein each break is a cut made in the flat material.

3 . The insulation element according to claim 1 , wherein at least part of each break does not extend orthogonally to the two surfaces of the flat material.

4 . The insulation element according to claim 1 , wherein the flat material has a degree of thermal conductivity of less than 10 Wm −1 K −1 .

5 . The insulation element according to claim 4 , wherein the flat material comprises carbon fibres and/or expanded graphite.

6 . The insulation element according to claim 1 , wherein the at least one break comprises at least 2 breaks.

7 . The insulation element according to claim 1 , the shape of the insulation element is approximated by a hollow cylinder, wherein the length, shape and orientations of each break at the outer surface of the flat material are selected such that the following applies:

LU>a·Lt

whereby

Lt is a length of the shortest path around the flat material that extends along the outer surface of the flat material, across each break, and into a central sectional plane that divides the flat material into two halves of equal flat material volume orthogonally to a longitudinal axis of the hollow cylinder,

Lu is a length of the shortest path around the flat material that extends from break to break in the central sectional plane in each case but does not pass across the respective break, instead passing around the respective break, and

a is 2 or 5.

8 . The insulation element according to claim 1 , wherein each break is at a spacing from two edges of the flat material.

9 . The insulation element according to claim 6 , wherein at least two breaks are inclined in the same direction with respect to the outer surface of the flat material.

10 . The insulation element according to claim 1 , wherein the flat material is a circumferentially continuous flat material containing carbon fibres.

11 . The insulation element according to claim 1 , wherein the flat material is formed from a set of flat material elements and at least one joint region that breaks the flat material across the entire flat material cross section is additionally provided between the flat material elements.

12 . A set of insulation element portions for forming an insulation element comprising the insulation element portions,

wherein at least one of the insulation element portions comprises a flat material having a specific electrical resistance ρF of 10 −5 to 10 −1 Ωm,

wherein the flat material comprises at least one break,

wherein the at least one break has a specific electrical resistance ρU≥100×ρF, and

wherein each break extends from an outer surface of the flat material and into the flat material but does not create a break in the flat material across the entire flat material cross section.

13 . A method for producing a flat material that can be used to insulate an inductively heated high-temperature treatment zone, comprising:

providing a flat material having a specific electrical resistance ρF in a range of 10 −5 to 10 −1 Ωm, and

forming at least one break in the flat material by cutting from a main surface of the flat material into the flat material without cutting through the entire flat material;

wherein the at least one break has a specific electrical resistance ρU≥100×ρF.