GB2234051A

GB2234051A - Combustion chamber lining brick

Info

Publication number: GB2234051A
Application number: GB9015841A
Authority: GB
Inventors: Jacques Raillat; Francois Chevasson; Jacques Ricard
Original assignee: Didier Werke AG
Current assignee: Didier Werke AG
Priority date: 1989-07-20
Filing date: 1990-07-19
Publication date: 1991-01-23
Anticipated expiration: 2010-07-19
Also published as: SE9002334D0; SE507823C2; BE1005648A5; GB9015841D0; GB2234051B; IT9048119A1; IT1241466B; DE8908821U1; NL9001555A; FR2650056B1; IT9048119A0; FR2650056A1; SE9002334L

Abstract

A lining brick (3) of refractory ceramic material for lining a combustion chamber wall includes an inner surface (5), a support surface (12) by means of which the brick may be supported in a direction substantially parallel to the inner surface and at least one undercut retaining groove (13, 14) which is open to the rear surface of the brick and affords a retaining surface (16) directed towards the inner surface of the brick and extends substantially parallel to the support direction. In use, one or more retaining elements (21) fixed with respect to the combustion chamber wall is received in the or each groove (13, 14) and engages the retaining surface (16) and thereby retains the brick in the direction perpendicular to the inner surface whilst its weight is supported by a support element (20) engaging the support surface (12). <IMAGE>

Description

COMBUSTION CHAMBER LINING BRICK The invention relates to a lining brick of refractory ceramic material for lining a combustion chamber wall and is particularly concerned with such a brick for lining a combustion chamber wall on which cooling tubes are arranged. The invention is concerned with that type of lining brick which has a support surface which engages and is supported by a support element fixed with respect to the wall whilst the brick engages the wall or the cooling tubes.

Such a lining brick is described in EP 0228918 Al. In this specification the support elements on the combustion chamber wall extend obliquely upwards. The support surface on the brick is correspondingly obliquely inclined. The oblique orientation of the support element is intended to result in the brick being retained both in the vertical and in the horizontal directions. A problem with this type of mounting is that reliable support in the horizontal and vertical directions may only be achieved if the support elements are positioned precisely correctly. If the support elements are not inclined at precisely the correct angle they will not properly engage the support surfaces of the bricks or they will not be aligned with the support surfaces.

A lining brick of the type referred to above is also described in DE-G 8809174 of the present applicant. In this specification- the upper and lower end faces of the brick extend obliquely to the inner surface, that is to say the surface which is directed inwardly towards the combustion chamber, and the support surface extends perpendicularly to the inner surface. This results in each individual brick in the lining structure being replaceable as well as being securely mounted in the lining structure. The brick is not retained in the horizontal direction against the wall or the cooling tubes by the support element. Instead, it is secured from slipping off the support element by the adjacent bricks below and above it whose inclined end faces engage those of the brick.

The object of the present invention is to provide a lining brick of the type referred to above in which the above disadvantages do not arise.

According to the present invention a combustion chamber wall lining brick of refractory ceramic material has an inner surface which, in use, is directed towards the interior of the combustion chamber, a support surface by means of which the brick may be supported in a direction substantially parallel to the inner surface and at least one undercut retaining groove which is open to a surface substantially oppposed to the inner surface and affords a retaining surface directed towards the inner surface and extends substantially parallel to the support direction whereby, in use, one or more retaining elements fixed with respect to the combustion chamber wall are received in the or each retaining groove and engage the retaining surface and thereby retain the brick in the direction perpendicular to the inner surface whilst its weight is supported on the support surface.

It is preferred that the brick has two parallel retaining grooves and that the support surface is located between them.

In use, the lining bricks may be retained in direct engagement with the combustion chamber wall and in this event the support elements and retaining elements will be connected directly to the wall. However, the lining brick is particularly suitable for lining a combustion chamber wall against which there is a plurality of cooling tubes and in this event it is preferred that the brick has at least one part-cylindrical concave surface substantially opposed to the inner surface, the retaining groove or grooves being open to respective concave surfaces, whereby, in use, the or each concave surface of the lining brick is retained against a respective cooling tube by retaining elements secured to the cooling tubes.

Thus the brick in accordance with the invention is supported in the support direction on one portion of the brick and is retained against the wall by a retaining element which engages a different portion of the brick. The brick is supported in the support (e.g.

vertical) direction with its support surface resting on a support element. In the direction perpendicular thereto (e.g. the horizontal direction), the brick is retained against the wall or the cooling tube or tubes by -the retaining element or elements which engage in the retaining groove or grooves. The horizontal mounting does not need to take the weight of the brick since the weight is taken by the support element.

There is thus no danger of the material around the retaining groove breaking. The support surface can be simply constructed so that it is strong enough to support the weight of the brick without being damaged.

Since the functions of supporting the brick and retaining it against the wall or cooling tubes are performed by different parts of the brick these parts may easily be designed to meet their respective design requirements.

Due to the fact that the retaining grooves are elongate the retaining elements are unrestrained in the vertical direction. The retaining elements therefore need not be exactly located on the wall or cooling tubes in the vertical direction.

The brick is retained closely against the cooling tubes by the retaining elements and this facilitates the transfer of heat from the brick to the cooling tubes.

The end surfaces of the brick can extend perpendicular to the inner surface or obliquely to it. Since the end surfaces of the brick do not play a part in supporting or retaining the brick, their shape can be so selected that dust or corrosive components of the gas within the combustion chamber is effectively prevented from penetrating between adjacent bricks.

It is preferred that the or each retaining groove is open at its lower end and it may in fact be open at both ends of the brick.

It is preferred that the or each retaining groove is substantially T-shaped in cross-section. In this case the retaining surface will be substantially parallel to the inner surface of the brick but it will be appreciated that this is not essential. It is necessary merely that the retaining surface extends in a direction which has a component parallel to the inner surface.

The present invention also embraces a combustion chamber wall lined with a plurality of such lining bricks. As mentioned above, the support elements and retaining elements may be secured directly to the wall or, if cooling tubes are present, that they are secured to these cooling tubes.

Further advantages and features of the invention will be apparent from the following description of one specific embodiment given by way of example with reference to the accompanying drawings, in which: Figure 1 is a front elevation, in the direction H in Figures 2 and 3, of a lining brick in accordance with the invention; Figure 2 is a plan view, along the line II-II, of a lining brick in position against cooling tubes on a combustion chamber wall; and Figure 3 is a side elevation in the direction of arrow III in Figure 1.

Cooling tubes 2 extend vertically against a combustion chamber wall 1. They are shielded from the combustion chamber 4 by bricks 3, one of which is shown in the Figures, which, in use, form the inner surface of the combustion chamber 4 with the cooling tubes sandwiched between the bricks 3 and the combustion chamber wall 1.

The cooling tubes 2 are thus protected against the heat of the combustion chamber 4 and the chemical action of the gas in the combustion chamber 4.

The bricks 3 comprise a refractory, ceramic material, for -instance one based on alumino silicate, silicon carbide or silicon carbide bonded with silicon. The bricks 3 are cooled by the cooling tubes 2.

Each brick 3 has a flat inner surface 5 on the chamber side. On the rear face, opposed to the inner surface, each brick is provided with a number of concave, partcylindrical surfaces 6,7,8. The radius of the concave surfaces corresponds to the radius of the cooling tubes 2 such that, in use, the surfaces 6,7,8 closely engage respective cooling tubes 2 (see Figure 2). In the exemplary embodiment, each brick 3 extends over three cooling tubes 2 and thus three concave surfaces 6,7,8 are provided on each brick 3. The remainder of the description will refer to such a brick, in place against three vertical cooling tubes running up the wall 1 of a combustion chamber.

The upper end face 9 and the lower end face 10 of the brick 3 extend obliquely to the inner surface 5 and preferably extend downwardly from the inner surface 5 (see Figure 3).

At the bottom of the brick 3, in the region of the central concave surface 7, the brick 3 has a recess 11.

This is open rearwardly to the concave surface 7 and downwardly to the lower end face 10. The upper wall of the recess 11 provides a support surface 12 which extends perpendicular to the inner surface 5.

In the region of each outer concave surface 6,8 the brick 3 is provided with a respective groove 13,14.

Each groove 13,14 includes a slot 15 which is open to the respective concave surface 6,8. Each groove 13,14 is undercut and extends laterally within the brick 3 to a greater extent than the respective slot 15 and thus each groove 13,14 has a T-shaped cross-section.

Retaining surfaces 16 are thereby provided on each side of each slot 15, preferably parallel to the inner surface 5 and facing inwardly. The grooves 13,14 extend parallel to one another and perpendicular to the plane in which the support surface 12 lies. The upper ends of the grooves 13,14 are open to the upper end face 9. At the bottom they each terminate at a respective recess 17,18, each of which is shaped like the recess 11. Between the recesses 17,11,18 are webs 19 which define the lateral extent of the recess 11 and provide one side wall of each recess 17,18.

Secured to the central cooling tube 2 is a, preferably horizontally extending, support plate 20 which has the approximate dimensions of the support surface 12. The brick 3 rests on the support surface 12 which bears on the support plate 20 in the vertical direction V.

T-shaped retaining elements 21 are secured to the two outer cooling tubes 2 (see Figure 2). These extend through the slots 15 into the grooves 13,14. They engage the retaining surfaces 16 and retain the brick 3 in the horizontal direction H with its concave surfaces 6,7,8 held closely against the cooling tubes 2.

The retaining elements 21 are substantially shorter in the vertical direction V than the grooves 13,14.

In practice the assembly of such a brick 3 to three cooling tubes is simple. The brick is placed against the cooling tubes 2 such that the retaining elements 21 of the cooling tubes 2 enter the recesses 17,18 of the brick 3. The brick 3 is then moved downwardly and the retaining elements 21 enter into and engage in the grooves 13,14. The brick 3 is then moved down further until its support surface 12 rests on the support plate 20. The brick 3 is thus supported in the vertical direction V by the support plate 20 and retained in the horizontal direction H in close engagement against the cooling tubes 2 by the retaining elements 21.

The brick is also suitable for mounting on cooling tubes which are inclined to the vertical direction V in any plane. The end faces 9,10 can be so shaped that gases or dust from the interior of the combustion chamber penetrate very little into the gaps between the end faces of adjacent bricks. Thus the end faces may be inclined or stepped or have any other configuration which would achieve this effect. Adjacent bricks 3 can also be arranged offset from one another against the cooling tubes 2. The invention is not limited to a brick for use in a combustion chamber having cooling tubes, since such a brick may equally be attached directly to a combustion chamber wall having the necessary support plate 20 and T-shaped retaining elements 21.

Claims

1. A combustion chamber wall lining brick of refractory ceramic material having an inner surface which, in use, is directed towards the interior of the combustion chamber, a support surface by means of which the brick may be supported in a direction substantially parallel to the inner surface and at least one undercut retaining groove which is open to a surface substantially opposed to the inner surface and affords a retaining surface directed towards the inner surface and extends substantially parallel to the support direction whereby, in use, one or more retaining elements fixed with respect to the combustion chamber wall is received in the or each retaining groove and engages the retaining surface and thereby retains the brick in the direction perpendicular to the inner surface whilst its weight is supported on the support surface.

2. A lining brick as claimed in claim 1 having two parallel retaining grooves, the support surface being located between the retaining grooves.

3. A lining brick as claimed in claim 1 or 2 for lining a combustion chamber wall against which there is a plurality of cooling tubes, the brick having at least one part-cylindrical concave surface substantially opposed to the inner surface, the retaining groove or grooves being open to respective concave surfaces, whereby, in use, the or each concave surface of the lining brick is retained against a respective cooling tube by retaining elements secured to the cooling tubes.

4. A lining brick as claimed in any one of the preceding claims wherein the or each retaining groove is open to both ends of the brick.

5. A lining brick as claimed in any one of the preceding claims wherein the or each groove is T-shaped in cross-section.

6. A lining brick as claimed in any one of the preceding claims wherein the support surface is substantially perpendicular to the inner surface.

7. A lining brick as claimed in any one of the preceding claims wherein the support surface partly defines a downwardly open recess in the brick.

8. A lining brick as claimed in any one of the preceding claims wherein the support surface is laterally defined by webs extending in the support direction.

9. A lining brick as claimed in any one of the preceding claims wherein the or each retaining groove communicates with a recess in the brick which is open in the direction in which the support surface faces.

10. A lining brick substantially as herein specifically described with reference to Figures 1 to 3 of the accompanying drawings.

11. A combustion chamber wall lined with lining bricks as claimed in any one of the preceding claims, a plurality of retaining elements affording a retaining surface directed towards the combustion chamber wall being fixed with respect to the wall and projecting from it and being received in a retaining groove in a respective lining brick with the retaining surfaces on the retaining elements engaging the retaining surfaces on the bricks thereby retaining the bricks in position in the direction perpendicular to the inner surfaces of the bricks whilst the weight of the bricks is supported by support elements which are fixed with respect to the chamber wall and project therefrom and engage the support surfaces of the bricks.

12. A combustion chamber wall as claimed in claims 11 and 3 against which there are a plurality of cooling tubes, the retaining elements and the support elements being secured to cooling tubes which are received in concave surfaces in the lining bricks.