GB2356689A

GB2356689A - Thermal insulation having a glass fibre sheath

Info

Publication number: GB2356689A
Application number: GB0028139A
Authority: GB
Inventors: Lutz Asperger
Original assignee: KULMBACHER KLIMAGERAETE
Current assignee: KULMBACHER KLIMAGERAETE
Priority date: 1999-11-24
Filing date: 2000-11-17
Publication date: 2001-05-30
Also published as: DE19956588A1; GB0028139D0

Description

2356689 THERMALLY INSULATING BODIES The invention relates to thermally

insulating bodies, particularly plates, of the type comprising a mixture of pulverulent insulating material and fibrous material within a glass fibre sheath. The invention is concerned particularly, though not exclusively with such bodies for shielding or insulating electric storage heaters. The invention also relates to a method of manufacturing such insulating bodies.

Insulating plates may be manufactured ftom pulverulent materials in a variety of ways. One possibility is to mix the powder with a bonding agent and to form plates from the mixture. It is also known to produce composite plates using pulverulent materials in conjunction with fibrous materials. A third possibility comprises fixing the pulverulent materials with additives in a glass fabric sheathing and thereafter pressing them to form plates. It is also known to sinter pulverulent materials by the action of heat to form bricks and plates.

An analysis of the prior art has revealed surprisingly that the various shaping technologies are always used in conjunction with special pulverulent materials.

For instance, silica is specially fired to form bricks and plates. Calcium silicate plates are only to be found in composites with cellulose fibres and vermiculite plates are bonded with bonding agents.

2 Furthermore, the only insulating plates with a glass fibre sheathing -which are known are those whose most important principal insulating material, in addition to opacifiers and fibres, is highly dispersed silica.

In accordance with the present invention, it has been found that, in addition to highly dispersed silica, other pulverulent insulating materials are also highly suitable for manufacturing insulating bodies with a glass fabric sheath. The pulverulent insulating material is preferably one or more of calcium 10 silicate, silica bricks or kieselguhr. The silica bricks are ground into pulverulent form before being used. Other comparable pulverulent insulating materials may also be used. When manufacturing an insulating body in accordance with the invention, a 15 pulverulent insulating material comprising one or more of calcium silicate, ground silica bricks or kieselguhr is mixed with a fibrous material, preferably glass fibre material. It is preferred that the fibres have a diameter of less than 2Vm and a length of less than 5mm. The ratio of length to diameter is preferably less than 2. Other known fibrous materials may, however, also be 20 used. The grain size of the pulverulent insulating material is preferably less than Imm. The mixture preferably comprises 80 to 95%, preferably about 90%, of the insulating pulverulent material and 5 to 15%, preferably about 10%, fibrous material. The insulating material can include up to about 40% of an opacifier. It is also possible for it to include an amount of up to about 10% 25 pyrogenic silica. The components of the mixture are intimately mixed and inserted into a glass fibre sheath or envelope which is then stitched or otherwise 3 closed. The sheathed mixture is then pressed into the desired shape, e.g. into a plate.

In a specific embodiment the mixture comprised 90% pulverulent insulating material and 10% fibrous material. In a further embodiment the mixture contained 60% pulverulent insulating material, 30% opacifier and 10% fibrous material. In a yet further embodiment the mixture comprised 50% calcium silicate, 10% highly dispersed (pyrogenic) silica, 30% opacifier and 10% fibrous material.

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Claims

1. A method of manufacturing a thermal insulating body in which a mixture of a pulverulent insulating material and a fibrous material are introduced into a glass fibre sheath and pressed, the pulverulent insulating material comprising a material other than highly dispersed silica.

2. A method as claimed in Claim 1, in which the pulverulent insulating material is calcium silicate, silica bricks or kieselguhr.

3. A method as claimed in Claim 2, in which the pulverulent insulating material is a mixture of at least two of calcium silicate, silica bricks and kieselguhr.

4. A method as claimed in any one of Claims I to 3, in which the mixture additionally includes an opacifier.

5. A method as claimed in any one of Claims I to 4 in which the average grain size of the pulverulent insulating material is less than I mm.

6. A method as claimed in any one of Claims I to 5 in which the fibrous material has a diameter greater than 2 [tm and a length less than 5 pin and the ratio of length to diameter is less than 2.

7. A method as claimed in any one of Claims I to 6 in which the mixture contains 80 to 95% pulverulent insulating material and 5 to 15% fibrous material.

8. A method as claimed in any one of Claims I to 7 in which the pulverulent insulating material includes up to 40% of an opacifier.

9. A thermal insulating body comprising a glass fibre sheath, which contains a pressed mixture of pulverulent insulating material and a fibrous material, the pulverulent insulating material comprising a material other than highly dispersed silica.

10 10. A thermal insulating body as claimed in Claim 9, in which the pulverulent insulating material is calcium silicate, silica bricks or kieselguhr.

11. A thermal insulating body as claimed in Claim 9 or 10, in which the pulverulent insulating material is a mixture of at least two of calcium silicate, 15 silica bricks and kieselguhr.

12. A thermal insulating body as claimed in any one of Claims 9 to 11, in which the mixture additionally contains an opacifier.

13. A thermal insulating body as claimed in any one of Claims 9 to 12, in which the average grain size of the pulverulent insulating material is less than 1 mm.

14. A thermal insulating body as claimed in any one of Claims I I to 13, in 25 which the fibrous material has a diameter greater than 2 Lrn and a length less than 5 gm and the ratio of length to diameter is less than 2.

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15. A thermal insulating body as claimed in any one of Claims 9 to 14, in which the mixture contains 80 to 95% pulverulent insulating material and 5 to 15% fibrous material.

16. A thermal insulating body as claimed in any one of Claims 9 to 15, in which the pulverulent insulating material includes up to 40% of an opacifier.