GB2289105A

GB2289105A - Anchor for mounting monolithic refractory ceramic linings

Info

Publication number: GB2289105A
Application number: GB9509063A
Authority: GB
Inventors: Peter Nebgen
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-05-06
Filing date: 1995-05-04
Publication date: 1995-11-08
Anticipated expiration: 2015-05-04
Also published as: DE4416022C2; GB9509063D0; GB2289105B; DE4416022A1

Description

REINFORCING ANCHOR 2289105 The invention relates to a reinforcing anchor

such as is used, for example, for reinforcing a monolithic, refractory ceramic lining in a metallurgical vessel, a chemical plant or a combustion chamber.

Without limiting the field of use of the invention, the prior art and the invention will be described in detail below with reference to a reinforcing anchor (reinforcing means) for reinforcing a combustion chamber in the petrochemical industry.

Refractory monolithic claddings have the advantage compared with a lining by means of shaped bricks that they can be applied quickly and easily, and independently of the local geometric factors to a very large extent.

Defective areas can likewise be easily repaired.

Disadvantageous is that the adhesion to the vessel outer wall represents a major problem. Under temperature loading, in particular, varying thermal expansions of the mostly metallic housing and the refractory cladding, and consequently movements in the refractory/housing contact area, occur. This results in shear stresses that can be so great that the refractory cladding collapses.

Particularly in cases where an insulating layer (for example fibre mat) is disposed between the housing and the refractory cladding, problems arise with regard to the stability of the refractory cladding.

There has therefore been no lack of attempts to stabilize the refractory cladding by means of suitable reinforcements.

Honeycomb-type grids are known, which are f ixed to the inner wall of the housing for example by welding, wherein the honeycombs are filled with the refractory material. Disadvantageous with this system is that mechanical stresses spread through the whole grid.

Attention has therefore switched to using separate reinforcing anchors instead of spacious grids. In the simplest case these are constructed after the manner of 11wing screws" and are welded to the inner wall of the housing.

Many other systems are known, for example that according to EP 0 530 895 Al.

Another system is described in GB 2 164 132 A (Plibrico). Ring segments are mainly involved here, which are likewise welded onto the inner wall to be lined.

Didier-Werke AG, Wiesbaden, supply a reinforcing anchor that comprises a U-shaped base member. This base member is secured to a metal support consisting of two plates that are held at a distance from one another by a bolt (double-T). For fabrication the U-shaped member is pushed onto the bolt and fixed between the plates. The whole of the assembly can be covered by a peripheral plastics ring.

All of the aforementioned systems have the disadvantage that the anchors are able to move to only a slight extent if at all. Either they are fitted rigidly directly to the vessel wall or - like the Didier anchor - held between two metal plates. Thermal expansions /contractions can at best be offset in one plane.

With high-temperature applications in particular, howeverf there occur as shown - considerable relative displacements between the housing and the refractory lining as the result of thermal longitudinal variations.

The invention is intended to remedy this situation and A c 3 - provide a reinforcing anchor that permits movement over wide areas and preferably in all directions of the coordinate system, without affecting the reinforcement function.

The invention is based on the consideration that the reinforcing anchor (including its holding means) must be so constructed that for the positioning (during the fitting) it is held or guided reliably with the desired alignment in the holding means. The holding means are so constructed, however, that they burn out under the influence of heat and thus create for the reinforcing anchor a "movement area" along which the anchor can Ormigrate" in the event of thermal or mechanical stresses.

Since the burning out of individual sections of the holding means can take place only after application of the monolithic lining, the inventive idea also provides that the holding means be covered with a cap after the fitting of the anchor, so that the holding area for the anchor remains free of refractory material, whereby a further "movement area" for the anchor can simultaneously be created.

Consequently the anchor - after the burning out of the above-mentioned parts - is able to move freely in the area of the holding means, wherein the holding means are secured to a bolt that can be secured in turn to the housing wall in any manner, for example by welding, screwing or similar.

In its most general form of execution the invention relates to a reinforcing anchor with the following features:

- a bolt with a first and a second end, wherein - the first end is provided with means for securing to a wall, and - the second end is provided with holding means for accommodating a U-shaped section of the anchor around the bolt, the free ends of the anchor, starting from the Ushaped section, run after a deflection away from the wall, the holding means for accommodating the U-shaped section of the anchor can be covered by means of a cap and are madef like the cap, in their part supporting the anchor on the wall side, at least partly of a burning- out material.

Depending on whether the anchor is to be secured by its U-shaped member directly on the wall side or at a distance from the wall, not only are varying lengths obtained for the bolt, but in certain cases also different forms of execution for the holdings means.

For example, in the event of a direct wall-side fitting the wall-side section of the holding means can be formed by the wall itself. In this case it is then only necessary to provide the burning-out part, preferably directly on the wall, and at a distance therefrom a further (non-burningout) holding means on the bolt, so that the anchor can be positioned with its U-shaped member between the burning-out part and the further holdings means.

After the f itting only the cap is then put in place, which naturally comprises matching recesses in the area of the anchor members.

For the case in which the holding means are to be disposed at a distance f or the wall-side securing of the bolt, two non-burning-out holding means are disposed at a distance from one another and a further, burning-out part is placed between the two so that the anchor can once again be fixed with its U-shaped member between the burning-out part and a corresponding holding plate. In this case also the whole of the holding means are then 4 covered again with a cap.

The cap and the burning-out part, which is preferably supporting on the wall side, can be made of the same material, for example a plastics material. Since both parts have to fulfil only temporary functions, lowpriced and/or recycled grades can be used.

Preferably both parts are of the same material and are connected to one another by the material. In the simplest case the cap is to this end connected to the burning-out part of the holding means by a corresponding bridge. This has the advantage that the cap cannot get lost during the fitting. The fitter can easily place the cap on the holding means after the fitting.

The form, size and range of materials for the holding is means are in principle optional as a function of the parameters mentioned above. Where the term "discs" is used below, this covers all kinds of " plate- shaped" holding means, including tube- and sleeve-type bodies, provided these are suitable for receiving and fixing the anchor during the fitting.

In the simplest case round discs will be used. The lower (wall-side) disc can be supported on a radialouter collar of the bolt or radially projecting pins. The burning-out part of the holding means, which can be formed for example after the manner of a "collar", is then placed on the wall-side disc, after which the U shaped member of the anchor is pushed onto the bolt and f inally a further disc and a nut are put in place, for which purpose the bolt has an external thread on its free end. The whole assembly can be tensioned by means of the nut so that the anchor is inserted and held reliably between the discs and/or the burning-out collar.

Similarly it is also possible, however, to construct the discs with a radial slot and to push them onto the bolt at the outer periphery of the bolts by means of matching slots.

The invention is limited neither to the one nor to the other form of execution. Instead the man skilled in general mechanical engineering has at his disposal a large number of other connection possibilities, without departing from the inventive idea.

The positioning of the anchor is further optimized if in particular the burning-out part of the holding means has a matching U-shaped depression on its surface, so that the U-shaped member of the anchor can be inserted and aligned there.

It is essential for the inventive idea that the whole of the connection area between anchor and holding means can be covered by means of the above-mentioned cap prior to the lining with said refractory mass and that this cap, together with the burning-out holding means, is then removed by raising of the temperature. An area free of refractory compound and other materials is consequently obtained between the holding means, in which the anchor is able to move freely in all directions of the coordinate system in the event of thermal or mechanical stresses.

Further features of the invention follow from the features of the subclaims and from the other application documents.

The invention will be explained in detail below by means of an embodiment.

Figure 1 shows - in diagrammatic view - a section through a reinforcing anchor according to the invention and Figure 2 a side view of an anchor.

There is shown with the reference symbol 10 a wall of a vessel, to the inner side of which (inner f ace 10i) a ceramic refractory compound is to be applied as a protective layer.

A bolt 12 is welded (weld seam 14) onto the inner face 10i of the wall 10. The bolt 12 has an external thread 12a at its free end.

During the fitting there is first of all pushed onto the bolt 12 after the securing of the bolt 12 a plastics collar 16, whose inner bore is somewhat greater than the outer bore of the bolt 12 and which has a peripheral flange 16f at its wall-side end. As the figure shows, the collar 16 lies with the flange 16f on the inner face 10i of the wall 10.

The width of the f lange 10f is selected so that the flange 10f can easily accommodate a U-shaped member 18u of an anchor 18, which is then pushed laterally (i.e. at right angles to the centre line M of the bolt 12) onto the collar 16.

The figures show that the two free ends 18e of the anchor 18, starting f rom the U-shaped member 18u, are bent upwards, so that they later lie in the refractory compound.

There is then placed on the bolt 12 a metallic ringshaped disc 20, which is supported on the upper front surface 16s of the collar 16 and is thereafter moved with the aid of a nut 22 in the direction of the wall 10 until the U-shaped member 1Bu of the anchor 18 is secured reliably and permanently between the disc 18 and the flange 16f of the collar 16.

In each position the anchor 18 can be moved only with f orce.

At one end of the flange 16f of the collar 16 there is integrally moulded a strip 24s, to whose other end a plastics cap 24 is positively secured.

After the fitting described above the cap 24 is slipped over the entire assembly, as shown in the figure. The cap 24 naturally possesses for this purpose two "gate-type" recesses 24a, corresponding to the arms 18e of the anchor 18.

In the mounted position the cap 24 - as the figure shows - covers completely the bolt 12, the nut 22, the disc 20, the U-shaped section 18u of the anchor 18 and the collar 16.

After a large number of anchors of the kind described have been secured to the wall 10 in the manner mentioned, the monolithic refractory lining can be applied. Because of the cap 24 the area below the cap 24 remains free of refractory material.

If thermal loading of the refractory material occurs after the start-up, this leads to a corresponding temperature drop from the inside to the outside (wall 10). As soon as in the area of the cap 24 and/or of the collar 16 the temperature lies above the melting point of these parts, the latter melt. At the same time the U shaped section 18u of the anchor 18 loses its support by the collar 16. It is obvious that the anchor 18 can then follow in the area between the disc 20 and the wall 10 movements in all directions of the coordinate system within the free area 30 formed, so that thermal/mechanical stresses between refractory cladding and wall 10 can now be offset by the anchors 18 and no longer lead to crack formation within the refractory material.

It is ensured by means of the cap 24 that the anchor 18 also does not come into contact with refractory compound peripherally in the area of the U-shaped member 18u and consequently the entire area below the cap remains free from refractory material.

The reinforcing anchor described can naturally be used not only as a reinforcing anchor for refractory claddings. It can also be used in conventional civil engineering, but in this case special care must be taken to ensure adequate heating of the burning-out parts, for example by means of burners or similar.

- 10

Claims

CLAIMS 1. Reinforcing anchor with the following features:

1.1 a bolt (12) with a first and a second end, wherein 1.1.1 the f irst end is provided with means (14) for securing to a wall (10) and 1.1.2 the second end is provided with holding means (16, 20) for accommodating a U-shaped section (18u) of the anchor (18) around the bolt (12), 1.2 the free ends (18e) of the anchor, starting from the U-shaped section (18u), run after a deflection away from the wall, 1.3 the holding means (16, 20) for accommodating the U-shaped section (18u) of the anchor (12) can be covered by means of a cap (24) and 1.4 are made, like the cap, in their part (16) supporting the anchor (18) on the wall side, at least partly of a burning-out material.

2. Reinforcing anchor according to claim 1, in which the cap (24) and the burning-out part (16) supporting the anchor (18) on the wall side are made of the same material.

91

3. Reinforcing anchor according to claim 1 or 2, in which the cap (24) is hinged to the burning-out part (16) supporting the anchor (18) on the wall side.

4. Reinforcing anchor according to one of claims 1 to 3, in which the cap (24) and the part (16) supporting the anchor (18) on the wall side are made of plastics material.

5.

Reinforcing anchor according to one of claims 1 to 4, in which the holding means (20) consist of temperatureresistant discs that accommodate the U-shaped section (18e) of the anchor (18) between one another.

6.

Reinforcing anchor according to claim 5, in which at least one disc (20) can be fastened to the bolt (12).

7.

Reinforcing anchor according to one of claims 1 to 6, in which the burning-out part (16) consists of a collar encompassing the bolt (12) and gripping the U-shaped anchor section (18u) from below.

8.

Reinforcing anchor according to one of claims 1 to 7, in which the discs are provided slotted and can be slipped along corresponding grooves on opposite sections of the bolt onto the latter.

9.

Reinforcing anchor according to one of claims 1 to 7, in which the discs (20) can be screwed onto the bolt (12) or positioned by means of nuts capable of being screwed on.

10. Reinforcing anchor according to one of claims 1 to 9, in which the non-burning-out, wall-side part of the holding means is formed by the wall (10) itself.

11. Reinforcing anchor substantially as herein described with reference to the accompanying drawing.