GB2103331A

GB2103331A - Heat-insulating casing for elongate constructional parts

Info

Publication number: GB2103331A
Application number: GB08218351A
Authority: GB
Inventors: Wedel Wedigo Von; Ulrich Schmidt
Original assignee: PROMAT
Current assignee: PROMAT
Priority date: 1981-06-27
Filing date: 1982-06-24
Publication date: 1983-02-16
Also published as: DE8118849U1; LU84219A1; FR2508594A1; BE893638A; NL8202590A; DE3125440A1; GB2103331B

Abstract

Heat-insulating casing for elongate constructional parts, especially for the fireproof insulation of tubes (10) in industrial furnaces, which consists of several rings (13), (17 Figure 3 not shown) which are cut out from a mineral-fibre mat with fibres oriented in one direction (15) and which are attached so as to surround the tube offset 90 DEG to one another and are glued to one another by means of their annular faces (14) so that most of the fibres are perpendicular to the wall of the tube (10) and to its longitudinal axis (20). The rings (17) may be rectangular, hexagonal or oval. <IMAGE>

Description

SPECIFICATION Heat-insulating casing for elongate constructional parts The invention relates to a heat-insulating casing for elongate constructional parts, especially for the fire-proof insulation of load-bearing tubes through which water flows in industrial furnaces.

In industrial furnace and plant construction, it is necessary to provide the usually water-cooled supporting, stay, carrying and sliding tubes with a heat-insulating casing in order to reduce the heating of the cooling water and to lessen the heat shock for these load bearing constructional parts of such furnaces during heating.

It is known to surround constructional parts of this type with shaped parts or with a fireproof material applied when moist or to wrap them round with mats made of ceramic fibres. Applying moist materials to the tubes requires special moulds and is laborious and expensive. To attach shaped parts, it is necessary to use complicated supporting devices, such as retaining brackets or the like, which have to be welded to the tubes or other constructional parts and have a complicated shape so that they can retain securely the shaped parts grouped round the constructional parts.The disadvantage of mineral-fibre mats, especially mats made from ceramic fibres, which hold together only because their fibres oriented essentially in one direction are felted, is that the composite structure of the fibres is lost when they are bent together to a narrow radius when wound round tubes and other constructional parts.

Moreover, because of the gas stream present in the furnace the composite structure of the fibres is loosened and they are blown away, so that the insulation quickly becomes thinner during operation. Furthermore, the fibres running parallel to the constructional part to be protected are sintered over their entire length, with the result that the insulating effect is further lessened.

The object of the invention is to avoid these disadvantages and to provide a very simple and highly effective heat-insulating casing for elongate constructional parts, especially for load-bearing tubes of industrial furnaces, which can be produced very simply and can be adapted to any cross-section and all insulating requirements of the constructional parts to be encased and which has only a very low weight.

According to the invention there is provided heat-insulating casing for an elongate constructional part, comprising a plurality of rings made from non-combustible fibre composites in which all the fibres are are substantially oriented in one direction of orientation and which rings packed tightly together are attached to the elongate constructional part to be insulated, in such a way that for each ring the direction of orientation of its fibres extends perpendicularly to the longitudinal axis of the elongate constructional part, and in that the fibre orientation directions of adjacent rings are offset at an angle to one another. The rings can suitably be cut from fibre mats or the like, made for example, of ceramic fibres.

The advantage of this design is that the fibres of the rings forming the casing are arranged at least partially transversely to the tube wall, and that part of a ring in which the fibres are oriented perpendicularly to the constructional part to be insulated or to a tube to be encased holds the part of the next ring in which the fibres run tangentially to the tube. As a result, on the one hand, a composite effect is achieved in the casing as a whole and, on the other hand, the disadvantage that all the fibres run parallel to the tube wall and can therefore flake off easily is avoided.

It is especially appropriate if the fibre directions of adjacent rings are offset 90 to one another. The fibre direction then changes from one ring to the next in such a way that the fibres of adjacent rings run perpendicularly to one another transversely to the longitudinal axis of the constructional part.

To achieve very great strength and an especially good composite effect, it is expedient to glue adjacent rings together by means of their annular faces resting against one another. For this purpose, a waterproof inorganic adhesive resistant to high temperature is appropriately used.

So that the rings can easily be attached from the side to the elongate constructional parts, they are appropriately cut open by a radial cut or consist of several ring parts, especially of two ring halves, which are then glued together again at their cut faces. It is advantageous, here, if the rings are cut open transversely to the fibre direction.

The rings can be adapted to any cross-sectional shape of the constructional part to be encased and need not be circular rings, but can also have the form of rectangular rings, hexagonal rings, oval rings or the like.

The rings can be glued directly by means of their inner peripheral faces onto the constructional part to be insulated, for example onto the outer periphery of a stay tube in an industrial furnace. However, it is especially appropriate if they are glued by means of their inner peripheral face onto a metal fabric, an expanded metal lattice or the like which is wrapped round the constructional part. As a result, the casing can easily be renewed, exchanged or repaired, without the constructional part to be insulated being affected thereby. The metal fabric itself can be welded to the tube to be insulated or can be fastened in another way. In general, however, it is sufficient to wind the metal fabric loosely or under tensile stress round the constructional part to be insulated.

The rings can be stamped out from various mineral-fibre mats, boards or webs. Preferably, they are cut out or stamped out from ceramic-fibre webs resistant to high temperature, the thickness of which should not exceed 10 cm.

When a metal fabric is used as a carrier for the insulating fibre rings, the metal fabric carrier on its outer periphery a bed consisting of an inorganic adhesive resistant to high temperature, to which the rings are glued by means of their inner peripheral faces. Good anchoring of the mineral fibres on the metal fabric is thereby achieved.

Further features and advantages emerge from the following description and the drawings in which especially appropriate embodiments of the invention are explained in more detail with reference to examples. In the drawings: Figure 1 shows a heat-insulating casing according to the invention, attached to a stay tube of an industrial furnace, in a partial perspective representation in which individual parts are cut away; Figure 2 shows, in a plan view, two adjacent rings of the casing according to Figure 1; and Figure 3 shows, in a plan view, two adjacent rings of another embodiment of the casing according to the invention.

In the drawings, 10 denotes a stay tube of an industrial furnace, through the interior 9 of which cooling water flows. Wound round the stay tube 10 isa metal fabric 11,theoverlapping edges ill and 1 1b of which are connected to one another in such a way that the metal fabric 11 rests firmly against the tube 10.

The metal fabric 11 is coated on its outer side with an adhesive bed 12. The adhesive is a waterproof inorganic adhesive resistant to high temperature, for example based on waterglass. Glued to this adhesive bed 12 is a plurality of rings 13 which surround the metal fabric 11 and the stay tube in a leak-proof manner and which rest closely on one another by means of their annular faces 14 facing one another.

The rings 13 are cut out or stamped out from a mass or a web of ceramic fibres which run essentially in one direction 15 in the web. In the exemplary embodiment illustrated in Figures 1 and 2, the rings 13 are circular rings which are cut open by a radial cut 16 extending transversely to the fibre direction 15. They can be opened by spreading the cut faces and displacing them relative to one another and can thereby be pushed from the side on to the stay tube 10 or onto the metal fabric 11 surrounding this.

It may be seen from Figure 1 that the rings 13 are arranged on the stay tube in such a way that the fibre directions 15 of adjacent rings 13 are offset respectively 900 to one another, so that the fibre direction 15 changes from one ring to the other.

The rings 13 are glued to one another not only at their end faces 14, but also at the cut faces of their radial cuts 16, so that they form a fixed block on the tube.

Figure 3 shows rings for another casing according to the invention. The rings 17, which serve for encasing a constructional part of rectangular crosssection not shown in any more detail here, each consist of two ring halves 1 7a and 17b of a rectangular ring, which, after being pushed onto the constructional part to be insulated, are glued together at their cut faces 18 and 19. It will be seen from Figure 3 that the cut faces 18 and 19 extend transversely to the fibre direction 15. Here again, successive rings 17 are glued to one another by meansoftheirannularfaces 14 so that the fibre directions 15 of adjacent rings run perpendicularly to one another.

It will be seen that the fibres of the part A of each ring are perpendicular to the tube wall and that the fibres oriented essentially in the direction 15 extend perpendicularly to the longitudinal axis 20 of the constructional part to be encased, here the stay tube 10. Consequently, the fibres of each ring are for the most part perpendicular to the adhesive bed 12 in the region A. As a result, they are anchored well in the adhesive bed. Since the fibres of none of the rings are bent, but are clamped between fibres extending perpendicularly to them and belonging to adjacent rings and are glued to these, they cannot become detached from the composite structure. On the whole sintering occurs only on fibre cut faces, so that the casing shrinks only insignificantly under the effect of heat.

The invention is not restricted to the exemplary embodiments, but several changes and additions are possible, without going beyond the scope of the invention. For example, the individual rings can also be arranged so that the fibres of adjacent rings extend at an acute angle to one another. It is even possible to give the outer periphery of the rings a different shape from their inner periphery and compose the rings of more than two ring parts. The wall thickness of the rings can be adapted to the particular requirements, as can their outline form which can, for example, also be cut to fit I-profiles.

Not only ceramic-fibre mats, but also other mineralfibre mats, boards or webs can be used as a starting material, and it is also possible to employ the heat-insulating casing according to the invention for the heat-insulation of heating tubes or the like. It will also be seen that the casing according to the invention is not confined in space to a specific position of the constructional parts to be encased, but can also be used for encasing horizontal or inclined constructional parts. Furthermore, instead of a metal fabric, metal lattices or expanded metal can also be used as a carrier.

Claims

1. Heat-insulating casing for an elongate constructional part comprising a plurality of rings made from non-combustible fibre composites in which all the fibres are substantially oriented in one direction or orientation and which rings packed tightly together are attached to the elongate constructional part to be insulated, in such away that for each ring the direction of orientation of its fibres extends perpendicularly to the longitudinal axis of the elongate constructional part, and in that the fibre orientation directions of adjacent rings are offset at an angle to one another.

2. Casing according to Claim 1, characterised in that the fibre orietation directions of adjacent rings are off-set at 90 to one another.

3. Casing according to Claim 1 or 2, characterised in that adjacent rings are glued together over their adjacent surfaces.

4. Casing according to any one of Claims 1 to 3, wherein the rings are cut out from fibre mats.

5. Casing according to one of Claims 1 to 4, characterised in that the rings each have a radial cut to allow installation over the elongate constructional member.

6. Casing according to one of Claims 1 to 4, characterised in that the rings consist of several ring segments.

7. Casing according to Claim 6 wherein there are two equal segments making up each ring.

8. Casing according to one of Claims 5, 6 or 7, wherein any cuts in the ring are made transversely to the fibre orientation direction.

9. Casing according to one of Claims 5 to 8, characterised in that each ring after installation is glued together at any cuts in it.

10. Casing according to one of Claim 1 to 9, characterised in that each ring is glued by means of its inner peripheral face onto a support fabric which is wrapped round the elongate constructional part.

11. Casing according to Claim 10 wherein the support fabric is a metal fabric.

12. Casing according to one of Claims 10 to 11, characterised in that the support fabric carries on its outer periphery an adhesive bed which consists of an inorganic adhesive resistant to high temperature and to which the rings are glued by means of their inner peripheral faces.

13. Casing according to one of Claims 1 to 12, characterised in that the rings are stamped out from ceramic-fibre webs resistant to high temperature.

14. Heat-insulating casing substantially as hereinbefore described with reference to the embodiment of Figures 1 and 2 or Figure 3.