EP1288601A1 - Heat shield brick and its use in a combustion chamber - Google Patents

Abstract

The heat shield component (1) is for fitting to a combustion chamber wall and has a hot side (3) for exposure to hot medium (M), opposing wall side (5) and a peripheral side abutting on the hot and wall sides. On the peripheral side (7) is a tractive component (11) to which a tension (Fz) is applicable to securely prevent the loosening of a piece of the heat shield component in the event of a breakage. At normal temperature, the tractive component is without tension and at a usage temperature above that normal, it is under tension. The peripheral side has a peripheral groove (13), in which the tractive component (11) engages.

Description

The invention relates to a heat shield brick, in particular for lining a combustion chamber wall, with a hot one Medium exposed hot side, one opposite the hot side Wall side and one on the hot side and the wall side adjacent circumferential side. The invention further relates to the use of a heat shield brick, in particular for lining a combustion chamber wall.

A thermally and / or thermomechanically highly loaded combustion chamber, such as a kiln, a hot gas duct or a combustion chamber of a gas turbine in which a hot medium generated and / or guided, is to protect against too high thermal stress with an appropriate lining Mistake. The lining usually consists of heat-resistant Material and protects a wall of the combustion chamber before direct contact with the hot medium and the associated severe thermal stress.

U.S. Patent No. 4,840,131 relates to an attachment of ceramic lining elements on a wall of an oven. Here is a rail system, which is attached to the wall and has a plurality of ceramic rail elements, intended. Due to the rail system, the lining elements to be held on the wall. Between one Lining element and the wall of the furnace can be further ceramic layers may be provided, including a layer of loose, partially compressed ceramic fibers, these Layer at least about the same thickness as the ceramic Lining elements or has a greater thickness. The Lining elements have a rectangular shape planar surface and consist of a heat-insulating, refractory ceramic fiber material.

U.S. Patent 4,835,831 also deals with application a refractory lining on a wall of a Oven, especially on a vertical wall. On the metal wall of the furnace becomes one of glass, ceramic or Mineral fiber existing layer applied. This The layer is made using metal clips or glue attached to the wall. On this layer there is a wire mesh network applied with honeycomb meshes. The mesh network also serves to secure the layer of ceramic fibers against falling. On the layer so fastened becomes uniform by means of a suitable spraying method closed surface made of refractory material. The method described largely avoids that refractory striking during spraying Particles are thrown back like a direct one Spray the refractory particles onto the metallic wall would be the case.

A ceramic lining of the walls of thermally highly stressed combustion chambers, for example gas turbine combustion chambers, is described in EP 0 724 116 A2. The lining consists of wall elements made of high-temperature-resistant structural ceramics, such as silicon carbide (SiC) or silicon nitride (Si ₃ N ₄ ). The wall elements are mechanically and resiliently fastened to a metal support structure (wall) of the combustion chamber by means of a central fastening bolt. A thick thermal insulation layer is provided between the wall element and the wall of the combustion chamber, so that the wall element is appropriately spaced from the wall of the combustion chamber. The insulation layer, which is about three times thicker than the wall element, consists of a ceramic fiber material that is prefabricated in blocks. The dimensions and the external shape of the wall elements can be adapted to the geometry of the room to be lined.

Another type of lining a thermally highly stressed Combustion chamber is specified in EP 0 419 487 B1. The lining consists of heat shield elements that mechanically are held by a metallic wall of the combustion chamber. The Heat shield elements directly touch the metallic wall. To avoid excessive heating of the wall, e.g. due to a direct heat transfer from the heat shield element or by introducing hot medium into each other adjacent column formed heat shield elements, is that of the wall of the combustion chamber and the heat shield element formed space with cooling air, the so-called sealing air applied. The sealing air prevents penetration from hot medium to the wall and at the same time cools the Wall and the heat shield element.

WO 99/47874 relates to a wall segment for a combustion chamber and a combustion chamber of a gas turbine. Here is a Wall segment for a combustion chamber, which with a hot Fluid, e.g. a hot gas that can be acted upon with a metallic one Support structure and one on the metallic support structure attached heat protection element specified. Between the metallic support structure and the heat protection element inserted a deformable separating layer, the possible relative movements of the heat protection element and the support structure and should largely compensate. Such relative movements can, for example, in the combustion chamber of a gas turbine, especially an annular combustion chamber, by different Thermal expansion behavior of the materials used or through Pulsations in the combustion chamber, as with an irregular one Combustion to produce the hot working fluid or can be caused by resonance effects. At the same time, the separating layer causes the relatively inelastic Overall heat protection element flat on the interface and the metallic support structure, because that Heat protection element partially penetrates the interface. The separating layer can cause unevenness due to the manufacturing process the support structure and / or the heat protection element, the local compensate for an unfavorable force input.

The invention is based on the observation that, in particular ceramic, heat shield stones due to their necessary Flexibility with regard to thermal expansion is often only insufficient against mechanical loads, such as Shocks or vibrations are secured.

The invention is accordingly based on the object Heat shield stone indicate, which both with regard unlimited thermal expansion as well stability against mechanical, especially shock-like, Guarantees high operational reliability. Another object of the invention is to provide a Use of the heat shield brick, especially for lining a combustion chamber wall.

The object directed at a heat shield brick is invented solved by a heat shield stone, in particular for lining a combustion chamber wall, with a hot one Medium exposed hot side, one opposite the hot side Wall side and one on the hot side and the wall side adjacent circumferential side, being on the circumferential side a tension element that can be pretensioned is attached is, with the pretension of the tension element detaching prevents a fragment formed in the event of a break becomes.

The invention shows a completely new way, heat shield stones against high accelerations due to Securing shocks or vibrations permanently. The invention is already based on the knowledge that heat shield stones, as usually used to line a combustion chamber wall be used by stationary and / or transient Vibrations in the combustion chamber wall to corresponding Vibrations are excited. Here, especially in a resonance case, significant accelerations above one Limit acceleration occur, taking the heat shield stones lift off the combustion chamber wall and then again crack open. Such a serve on the massive or too partially dampened combustion chamber wall leads to very high forces on the heat shield stones and can cause considerable damage, e.g. Lead to breakage of this. Add to that the extraordinary large thermal load on the heat shield brick due to the exposure of the heat shield stone to one hot medium in operation. Both on the wall side as well Cracks can thus appear on the hot side of the heat shield brick occur, with increasing crack growth in further operation also the danger of material coming out of the Heat shield stone exists. This leads to a considerable reduction the durability of a heat shield brick all because such cracks lead to a material breakdown and thus to breakage and complete failure of the entire heat shield brick being able to lead. As a result, there is acute Risk of fragments getting into the combustion chamber and others Components of the combustion chamber or, for example, when in use in the gas turbine, the sensitive blading area massive damage with turbine blades.

With the proposed heat shield stone with one on the circumferential side tension element that can be pretensioned, becomes an extremely efficient and long-term stable backup for the first time specified for a heat shield stone. Here is that Tension element advantageously in the circumferential direction on a Preload can be preloaded, with a corresponding compressive stress is generated inside the heat shield brick that the Stone clings together. Thus the heat shield stone is through the tension element is held under pressure pre-tensioning, so that on the bending tensile forces acting on the heat shield stone are reduced and the crack growth is slowed down. Because of this compressive stress, which at least partially towards the inside of the Heat shield stone is directed, the heat shield stone even with a comparatively low preload of the Tension element secured. In this way, a possible material tear, for example as a result of a shock load or thermal load, effectively countered. Existing material cracks can change with a corresponding geometric Design and arrangement of the tension element not or only to a limited extent along the hot side of the Develop or expand the heat shield stone. The tension element holds the heat shield stone together, so to speak, and secures it on the one hand against material cracks and on the other hand all compared to a complete material rupture. Next this primary safeguarding function also adds to the danger loosening or falling out of smaller or larger ones Fragments in the event of a possible material breakdown or break effectively countered. The through the Pre-tensioning of the tensile element causes compressive stress a detachment of a fragment formed in the event of a break.

An increase in passive safety is particularly advantageous of the heat shield stone compared to the conventional designs. A material tear or tear is indicated by the biased tension element countered, in the event of a tear removing a fragment of the heat shield brick is prevented.

By designing the heat shield brick with the tension element there is still the advantage of a problem-free Prefabrication and easy assembly of the heat shield brick, for example for installation in a combustion chamber. The tension element is simply attached to the circumferential side and pretensioned in the circumferential direction depending on the requirement, a predetermined tensile stress on the tensile element is imprinted. The tension element can be used during assembly also not yet be biased (zero bias); the preload occurs during operation at high temperature by the different coefficients of thermal expansion of tension element and stone. This high Flexibility on the one hand and the achievable durability the heat shield stone, on the other hand, are also in view particularly advantageous from an economic point of view. In particular, revision or maintenance intervals for the heat shield brick, for example when used in a Combustion chamber of a gas turbine are extended. in case of a The heat shield stone does not have to break immediately Operation to be revised because of due to continued operation until increased passive safety at the regular revision interval and even beyond is possible. The heat shield stone is therefore characterized special emergency running properties.

In a particularly preferred embodiment, one Normal temperature the tension element free of tension and at a The application temperature is above the normal temperature Tension element under the preload. The tension element is there advantageously dimensionable so that a targeted intended mismatch of thermal expansion coefficients between heat shield stone and tension element used for this is in operation, i.e. at an application temperature of up to to 1200 ° C of that hitting the hot side of the heat shield brick hot medium, a sufficiently large, through which Preload of the tension element mediated compressive stress on the Apply heat shield stone. This bias will but at the same time favorably set so low that it not to creep deformation and relaxation of the tension element leads or even in the size of the maximum allowable preload of the tension element comes. The normal temperature at which the Tension element is tension-free, is advantageous Room temperature, about 20 ° C, which is a particularly simple one Attach the tension element to the peripheral side of the heat shield brick enabled during assembly.

The bias is preferably directed in the circumferential direction, i.e. the bias has at least one component in the circumferential direction of the heat shield brick. The circumferential direction is essentially perpendicular to the surface normal the hot side or the wall side. This will possible fragments of the heat shield stone by a corresponding Compressive stress compressed in the circumferential direction. Removal of the fragments in the direction of the surface normal the hot side becomes due to a wedging effect the fragments prevented.

In a preferred embodiment, the peripheral side has a Circumferential groove in which the tension element engages. The circumferential groove is designed such that it the traction element largely integrated into the heat shield stone.

Generally, heat shield stones are circumferential secured by two so-called stone holder pairs, so that at Break in the circumferential direction of each fragment only by respective pair of stone holders is held. The stone holder pairs are on the circumferential side of the heat shield brick arranged opposite sides and put one first axis of the heat shield brick firmly. Along a second Axis perpendicular to the first axis and in Generally along the flow direction of the hot medium the hot side of the heat shield brick matches the heat shield stone on the circumferential side of the tension element receiving circumferential groove. The along the second axis opposite sides of the circumferential side also referred to as the face of the heat shield stone. each The end face can have a respective circumferential groove into which engages a respective tension element, which in operation under Preload is there. For a particularly advantageous and safe Engagement of the tension element in the circumferential groove can do this additionally with holes, for example blind holes, be provided at each end of the circumferential groove. This can the traction element is covered and thus fully integrated, so to speak be inserted or inserted into the heat shield stone and is advantageously thereby possibly inflowing hot gas not immediately exposed. To avoid mechanical or thermomechanical voltage increases Circumferential groove and possibly the additional holes rounded designed.

The peripheral side preferably has a peripheral side surface on, the tension element engaging in the circumferential groove in such a way that the tension element is set back against the peripheral side surface is or is flush with this. The tension element can be done constructively in different ways be and be designed so that a cheap Combination of low-tension design and less expensive Manufacturing is achieved. The cross section of the tension element can be rectangular, round or oval his. Advantageously, neither the tension element here still on the circumferential groove or possibly the additional holes sharp corners or edges created in the heat shield stone.

In a particularly simple and preferred geometric configuration the traction element comprises a web, on its axial Each ends essentially perpendicular to the web itself extending finger-shaped anchor is provided. Footbridge and Anchors have essentially the same shape and same cross section. After attaching the tension element the finger-shaped protrude on the circumferential side of the heat shield stone Anchors in respective holes in the heat shield brick into it, the web engaging in the circumferential groove. Favorable In this way, the web closes flush with the peripheral side surface starting with some play between tension element and the circumferential groove is to be provided, so that an in Thermal curvature of the Heat shield stones in the direction of the surface normal of the Hot side is tolerated.

The tension element preferably consists of a ceramic material, in particular of a Si ₃ N ₄ base ceramic. This high-temperature, creep and corrosion-resistant base ceramic, which was specially developed for high-temperature applications in a gas turbine atmosphere, appears to be particularly suitable for use as a tensile element due to the expected high operating temperatures of typically around 1000 ° C, but sometimes up to 1200 ° C. The pulling element can be made from an all-ceramic material, which can additionally be encased with elastic fiber-ceramic material on the finger-shaped anchors with which the pulling element engages in the interior of the heat shield brick. A particularly firm and durable anchoring of the tension element in the heat shield brick can thereby be achieved.

The tension element is preferably fastened by means of an adhesive. The tension element is at least partially with the Heat shield stone glued, the adhesive connection between the tension element and heat shield stone preferably in the area the finger-shaped anchor is to be provided. By gluing is an additional securing of the tension element against one possible detachment achieved and durability increased accordingly. When gluing the tension element with the Heat shield brick can be both a conventional adhesive as well as a high temperature resistant adhesive are used. Silicate-based adhesives can also be used excellent adhesive properties and great temperature resistance exhibit. Has proven to be particularly advantageous use a ceramic for the adhesive connection Material for the tension element.

In a particularly preferred embodiment, the tension element a channel into which the adhesive for anchoring of the tension element can be introduced.

For this purpose, the tension element can, for example, consist of a so-called Ceramic tube material to be made, thereby a Channel or a corresponding variety of channels for the Tension element is realizable.

In a configuration of the tension element with a web of that at a respective axial end perpendicular to the web branches finger-shaped anchors, are the finger-shaped anchors preferably over the entire axial extent of the finger-shaped Anchor and the entire circumference of the anchor with openings Mistake. A filling opening is also provided through which the adhesive can be introduced into the channel. To Inserting the tension element in the heat shield stone is the Adhesive through the fill opening in the channel or Large number of channels are sprayed and emerges from the openings the finger-shaped anchor out. After the adhesive has set can create a large-scale and firm bond between the heat shield brick and the tension element in the area the finger-shaped anchor can be achieved.

A further tension element is preferably provided, which is attached to the peripheral side and is opposite the tension element.

The tension element and the other is advantageous Traction element on a respective face of the heat shield brick attached, causing crack growth or breakage of the Avoid heat shield stone in the flow direction of the hot gas becomes.

The heat shield brick preferably consists of a ceramic Base material, in particular made of a refractory ceramic. By the choice of a ceramic as the base material for the heat shield brick is the use of the heat shield stone up to very high Guaranteed temperatures, while being oxidative and / or corrosive attacks, such as those applied the hot side of the heat shield brick with a hot medium, e.g. a hot gas, largely harmless to are the heat shield stone. The tension element is advantageous with the ceramic base material of the heat shield brick easy to connect. The fixed connection can also, as already mentioned above, as a detachable connection be designed. In addition to gluing also the attachment of the tension element by means of suitable fastening elements on the circumferential side, e.g. by an appropriate one Stapling or by screwing. Through the Choice of a tension element, but at least partially a ceramic material is also a good match to the ceramic base material of the heat shield brick achieved in terms of thermomechanical properties. By firmly anchoring the tension element to the base material the heat shield stone is advantageously at least at the high application temperature in a kind of solid composite designed with the tension element. This makes it compact Construction and structure of the heat shield brick given, which is extremely high durability and passive Security even with large thermal and / or mechanical Has loads. This is particularly large Advantage when using the heat shield brick in a combustion chamber, because even after a tear or material tear the Heat shield function of the heat shield brick continues to be guaranteed is, especially no fragments in the combustion chamber can reach.

Economically, this has the advantage on the one hand that in normal operation no extraordinary maintenance and / or revision of a heat shield stone Combustion chamber is required. On the other hand, the heat shield stone in the event of special occurrences about emergency running properties, causing consequential damage to a turbine, for example the blading of the turbine can be avoided. The combustion chamber can at least with the usual maintenance cycles operated, but also an extension of Downtimes due to the increased passive with the traction element Security can be achieved.

The one aimed at using a heat shield brick The object is achieved by using a Heat shield stone according to the above statements in one Combustion chamber, in particular a combustion chamber of a gas turbine.

The benefits of using the heat shield brick in one Combustion chamber, in particular a combustion chamber of a gas turbine, arise according to the explanations of the heat shield stone.

FIG 1 und 2

jeweils eine Seitenansicht eines Hitzeschildsteins mit Zugelement,

FIG 3

eine perspektivische Ansicht eines Hitzeschildsteins in einer Explosionsdarstellung,

FIG 4 und 5

jeweils eine Variante der Verklebung des Hitzeschildsteins mit dem Zugelement,

FIG 6

einen Hitzeschildstein,

FIG 7 und 8

eine jeweilige Ansicht des Zugelements des in FIG 6 gezeigten Hitzeschildsteins,

FIG 9

eine Hitzeschildstein mit einer Variante der geometrischen Ausgestaltung von Umfangsnut und Zugelement.

FIG 10 u. 11

eine jeweilige Detailansicht des in FIG 9 gezeigten Zugelements,

FIG 12

einen Hitzeschildstein mit einer weiteren geometrischen Variante des in die Umfangsnut eingreifenden Zugelements,

FIG 13 u. 14

jeweilige detaillierte Darstellungen des in FIG 12 gezeigten Zugelements.

The invention is explained in more detail by way of example with reference to the drawing. They show schematically and partially simplified:

1 and 2

each a side view of a heat shield brick with tension element,

FIG 3

2 shows a perspective view of a heat shield brick in an exploded view,

4 and 5

each a variant of the gluing of the heat shield brick to the tension element,

FIG 6

a heat shield stone,

7 and 8

6 shows a respective view of the tension element of the heat shield brick shown in FIG. 6,

FIG 9

a heat shield brick with a variant of the geometric design of the circumferential groove and tension element.

FIG 10 u. 11

5 shows a respective detailed view of the tension element shown in FIG. 9,

FIG 12

a heat shield brick with a further geometric variant of the tension element engaging in the circumferential groove,

FIG 13 u. 14

respective detailed representations of the tension element shown in FIG.

The same reference numerals have in the different figures same meaning.

1 shows a side view of a heat shield brick 1. The heat shield brick 1 has a hot side 3 and a wall side 5 opposite the hot side 3. A peripheral side 7 of the heat shield brick 1 is adjacent to the hot side 3 and the wall side 5. The peripheral side 7 has a peripheral side surface 9. The hot side 3 is acted upon by a hot medium M, for example a hot gas, when the heat shield brick 1 is used. On the circumferential side 7 of the heat shield brick 1, a tension element 11 is provided which is prestressed in the circumferential direction 17. The tension element 11 is biased to a bias F _Z. The peripheral side 7 has a peripheral groove 13, in which the tension element 11 engages. The prestress F _{Z of} the tension element 11 causes a compressive stress F _P on the material of the heat shield brick 1, which acts on a surface element A, for example. The tension element 11 is prestressed in such a way that the compressive stress F _P acts essentially along the circumferential direction 17 towards the center of the heat shield brick 1. To generate a bias F _Z in the circumferential direction 17, the tension element 11 has a certain elasticity. By adapting the material of the tensile element 11 and the base material of the heat shield brick 1, it can be achieved that the tensile element 11 is stress-free at a normal temperature, ie the pretension F _Z = 0. The normal temperature is preferably room temperature, ie about 20 ° C. This enables a particularly simple attachment of the tension element 11 to the peripheral side 7 of the heat shield brick 1 by inserting the tension element 11 into the peripheral groove 13. In addition, a certain play is provided between the tension element 11 and the circumferential groove 13 in the installed state, which is achieved through the gap 19.

By setting the thermal expansion coefficient of the base material of the heat shield brick 1 and the tension element 11 in a targeted manner, it is achieved that a sufficiently large prestress F _{Z can be} applied to the heat shield brick 1 during operation of the heat shield brick 1. For this purpose, the thermal expansion coefficient of the base material of the heat shield brick 1 is chosen to be greater than the thermal expansion coefficient of the tension element 11. At an application temperature above the normal temperature, which can be up to 1200 ° C. when the heat shield brick 1 is used in a gas turbine, this is achieved the tension element 11 is under the prestress F _Z. This is brought about by the relative thermal expansion between the base material of the heat shield brick 1 and the tension element 11. The tension element 11 is inserted into the heat shield brick 1 in a manner similar to a clamp and causes a centrally directed compressive stress F _P on the heat shield brick 1. This clamp function of the tension element 11 firmly clamps it together under operating conditions at the application temperature. The traction element 11 significantly increases the passive safety and thus the durability of the heat shield brick 1 when used in a combustion chamber, for example in the combustion chamber of a gas turbine. The heat shield brick 1 is largely protected, in particular, against the risk of crack formation from the crack propagation on the hot side 3, the wall side 5 or the peripheral side 7.

To illustrate this, FIG 2 shows a heat shield brick 1 with a tension element 11, wherein a crack 21 extends from the hot side 3 to the wall side 5 completely through the base material of the heat shield brick 1. The fracture of the heat shield brick 1 occurred in a central area of the heat shield brick 1. Due to the considerable thermal or mechanical stress, e.g. B. by impact on a combustion chamber wall, not shown, of a gas turbine, such a crack 21 of the heat shield brick 1 is caused. The crack 21 causes the heat shield brick 1 to be divided into a first fragment 57A and a second fragment 57B. The fragments 57A, 57B are pressed against one another along the circumferential direction 17 by the compressive stress F _P mediated by the tension element 11 on the heat shield brick 1. This reliably prevents a fragment 57A, 57B formed in the event of a break from being detached. Without the tension element 11 under prestress F _Z , on the other hand, there would be an acute risk of a fragment 57A, 57B being released from the composite in a direction essentially parallel to the surface normal of the hot side 3. The danger that the fragments 57A, 57B in those not shown in more detail Coming into the combustion chamber of a gas turbine and massively damaging further components of a combustion chamber or, for example when used in a gas turbine, the sensitive blading area of the turbine blades is effectively countered by the provision of the tension element 11. The heat shield brick shown in FIG. 2 has a fastening groove 15 for fastening the heat shield brick to a combustion chamber wall (not shown in any more detail), into which a mounting element 25A engages. Another mounting element 25B engages in the fastening groove 15 and is arranged along the circumferential direction 17 opposite the mounting element 25A. The wall side 5 faces a corresponding wall, not shown, of the combustion chamber when the heat shield brick 1 is installed, so that the heat shield brick 1 can be fastened in a spring-elastic manner to the wall, not shown, via the fastening elements 25A, 25B.

An exploded perspective view of the heat shield brick 1 is shown in FIG 3. The heat shield stone 1 essentially has a cuboid shape Geometry and extends along a flow direction 27 and a circumferential direction 17. The flow direction 27 forms when using the heat shield brick 1 in a combustion chamber a gas turbine, preferably also the direction, in which the hot medium M flows and with which the hot side 3 is applied (see also FIG 1 and 2). Through the Fastening groove 15 and the circumferential groove 13 disintegrate the circumferential side 7 functional in different areas 35A, 35B, 37A, 37B, the sections of the hot side 3 and form the wall side 5 adjacent peripheral side 7. The the Fastening groove 15 having partial area of the peripheral side 7 is referred to as the mounting side 35A, 35B during the the circumferential groove 13 receiving the tension element 11A, 11B Sub-area is referred to as the end face 37A, 37B. In the exploded view of FIG 3 are two tension elements 11A, 11B, which are not shown in FIG Circumferential groove 13 used, but removed from this are. The tension element 11A is a circumferential groove 13 in the Associated end face 37A, while the tension element 11B on the opposite the end face 37A along the flow direction 27 End face 37B is provided. Each of the tension elements 11A, 11B is designed in the form of a clamp and has one Web 29 and two finger-shaped anchors 31 each. The Finger-shaped anchor 31 is at the two longitudinal ends of the Web 29 arranged and projects substantially perpendicular to Longitudinal extension of the web 29 towards the inside of the Heat shield stones 1. Corresponding to the finger-shaped Anchors 31 have the circumferential groove 13 corresponding to the number of finger-shaped anchor 31 holes 33, e.g. Blind holes, on. In each of these holes 33 is when installing the tension elements 11A, 11B a finger-shaped anchor 31 for anchoring the Pulling element 11A, 11B can be inserted on the respective end face 37A, 37B.

A possible substantially central crack 21, through which the heat shield brick is divided into a first fragment 57A and a second fragment 57B, is bridged with the tension elements 11A, 11B. The pretension F _Z applied to the tension element 11A, 11B, as already described in connection with the discussion in FIGS. 1 and 2, prevents the fragments 57A, 57B from being removed.

For fastening or anchoring the tension elements 11A, 11B proposed various options, one of which is in Figures 4 and 5 exemplarily two preferred variants are illustrated. In both variants, the Finger-shaped anchor 31 with the ceramic base material 49 the heat shield stone 1 is provided. In FIG 4 there is a Adhesive 39 in the bore 33 before inserting the finger-shaped Anchor 31 introduced into the bore 33. For fixing of the tension element 11A, 11B becomes the finger-shaped anchor 31 inserted into the bore 33 provided with the adhesive 39, the finger-shaped anchor 31 in the adhesive 39 is pushed in. After the adhesive 39 has set, for example a ceramic adhesive, is a safe and permanent adhesive connection between the finger-shaped anchor 31 and the ceramic base material 49 of the heat shield brick 1 reached. The peripheral side 7 has a peripheral side surface 9, the tension element 11A, 11B or the web 29 of the tension element 11A, 11B, engages in the circumferential groove 13 in this way, that the tension member 11A, 11B with the peripheral side surface 9 ends flush. It is also possible that the tension element 11A, 11B toward the peripheral side surface in the direction the interior of the heat shield brick 1 is set back. By this configuration, the tension element 11A, 11B is covered and so to speak integrated into the heat shield brick 1 and thus not immediately flowing into a hot medium M. exposed. The proposed game in the form of a Gap 19 between the tension element 11A, 11B enables one largely unimpeded thermal bulging of the heat shield brick 1 in operation.

5 shows an alternative to FIG. 4 of gluing the tension element 11 to the ceramic base material 49 in the region of the bore 33. The tension element 11 has a channel 41 for this purpose. The channel 41 has an inlet opening 43, which is provided on the outer side of the tension element 11 on the web side facing away from the peripheral side 7. The channel 41 branches out and opens into a large number of outlet openings 45 in the finger-shaped armature 31. The tension element 11 with the web 29 and the finger-shaped armature 31 are preferably made of a ceramic material, for example an Si ₃ N ₄ base ceramic. In the present exemplary embodiment in FIG. 5, the tension element 11 consists of a ceramic tube material. The finger-shaped armature 31 has, for example, outlet openings 45 distributed over the entire axial extent of the armature 31 and over the entire circumference of the armature 31. To glue the tension element 11 to the material 49 of the heat shield brick 1 in the region of the bore 33, adhesive 39, for example a ceramic adhesive, is supplied to the channel 41 through the inlet opening 39. The adhesive 39 is preferably injected into the inlet opening, so that a uniform and complete distribution of the adhesive 39 in the entire channel 41 and an escape of the adhesive through the outlet opening 45 is possible. A large-area bond between the ceramic material 49 of the heat shield brick 1 and the finger-shaped anchor 31 is thus achieved. In this exemplary embodiment, the finger-shaped anchor 31 acts as a hollow anchor, via which the adhesive 39 can be brought very specifically to the regions in the bore 33 to be bonded.

In addition to using a ceramic tube material for the tie rod 11 is also the use of an all-ceramic possible, as shown for example in FIG. 4. additionally to use an adhesive 39 for gluing, the finger-shaped anchor 31 with which the tension element 11 in the Heat shield stone 1 engages with the elastic fiber ceramic Material to be wrapped. This strengthens the connection and the durability of the bond between anchor 31 and the ceramic material 49 in the blind hole 33.

In the following FIGS. 6 to 14, there are various constructive designs Variants of one attached to a heat shield brick 1 Tension element 11 shown graphically. Here is in Essentially the cross section of the tension element 11 and that Corresponding circumferential groove 13 receiving tension element 11 varies geometrically. Care should be taken to ensure that neither the pulling element 11 or sharp corners on the circumferential groove 13 Edges exist. To do this are in the critical areas Rounding 51 on the tension element 11 and accordingly on the circumferential groove 13 provided. 7 and 8 show two side views of the tension element 11, as it is in the heat shield brick 1 6 is used. The finger-shaped anchor 31 extends is essentially perpendicular to the web 29 and points a shaft region 53 and one on the shaft region 53 adjoining end section 55. The end section 55 is slightly enlarged in cross section compared to the shaft region 53, so that the anchor can be anchored particularly cheaply 31 can be achieved in the bore 33.

10 and 11 show a tension element 11 as it is according to the Embodiment of FIG 9 attached to a heat shield brick 1 is. The cross section of the tension element is here Essentially rectangular, but can also be square. The circumferential groove 13 corresponds to the selected geometry provided with a gap 19 and a rounding 51. Analogous to the exemplary embodiment in FIGS. 6 to 8, the tension element 11 has a finger-shaped anchor 31 which has a shaft region 53 and an end section 55 includes. Figures 12 to 14 show in an analogous manner Embodiment of the invention in which the tension element 11 has a substantially round or oval cross-sectional area.

In all of the above-described exemplary embodiments, the tension elements are fastened to the heat shield brick 1 preferably by means of gluing with an adhesive 39, for example a ceramic adhesive. The bonding has proven to be particularly favorable for the assembly of the heat shield brick 1 in a combustion chamber, where the heat shield bricks are used at a high application temperature. The adhesive bonding of the tension element 11 prevents the tension element 11 from being detached from the heat shield brick 1 at a normal temperature below the application temperature, that is to say when the tension element is preferably stress-free. The adhesive bonding can be carried out in such a way that a positive connection of the tension element 11 with the heat shield brick 1 is formed after curing. As a result, the tension element cannot fall out, even if the hardened adhesive 39 should break, since any fragments of the hardened adhesive would get caught. In an alternative embodiment, a positive connection between the tension element 11 and the heat shield brick 1 is also possible, it being possible entirely to dispense with an adhesive 39. In this case, a certain pretension F _{Z must be} applied to the tension element 11 at a normal temperature, for example room temperature. This bias serves as a holding voltage for securely clamping the tension element 11 to the heat shield brick 1 during assembly.

The advantages of the heat shield brick according to the invention lie in a significant increase in operational safety during use the heat shield brick in a combustion chamber, for example in a thermally highly loaded combustion chamber Gas turbine. In particular, machine damage as a result of Breakage or crack of the heat shield brick - what as a result of thermal and / or mechanical loads on the Heat shield stone can occur - avoid with great certainty because the pulling element detaches one from one Breakage formed fragment is prevented. Along with it is a significant increase in the life of the heat shield brick, because on the one hand the crack growth slows down and on the other hand a larger crack length up to the exchange limit can be approved. Hence a reduction the number and duration of forced stoppages of the Combustion chamber possible, which increases availability a system when using the heat shield brick for lining a combustion chamber wall, increased.

Claims (11)

Heat shield brick (1), in particular for lining a combustion chamber wall, with a hot side (3) which can be exposed to a hot medium (M), a wall side (5) opposite the hot side (3) and one on the hot side (3) and the wall side (5) adjacent peripheral side (7),
characterized in that on the circumferential side (7) a tension element (11, 11A) which can be pretensioned to a pretension (F _Z ) is attached, the pretension (F _Z ) of the tension element (11, 11A, 11B) releasing one at a time Breakage formed fragment (57A, 57B) is prevented. Heat shield brick (1) according to claim 1,
characterized in that the tension element (11, 11A, 11B) is stress-free at a normal temperature, and that the tension element (11, 11A, 11B) is under the pretension (F _Z ) at an application temperature above the normal temperature. Heat shield brick (1) according to claim 1 or 2,
characterized in that the bias (F _Z ) is directed in the circumferential direction (17). Heat shield brick (1) according to claim 1, 2 or 3,
characterized in that the circumferential side (7) has a circumferential groove (13) into which the tension element (11, 11A, 11B) engages. Heat shield brick (1) according to claim 4,
characterized in that the peripheral side (7) has a peripheral side surface (9), the tension element (11, 11A, 11B) engaging in the peripheral groove (13) such that the tension element (11, 11A, 11B) is opposite the peripheral side surface (9 ) is set back or is flush with it. Heat shield brick (1) according to one of the preceding claims, characterized in that the tension element (11, 11A, 11B) consists of a ceramic material (47), in particular of a Si ₃ N ₄ base ceramic. Heat shield brick (1) according to one of the preceding claims, characterized in that the tension element (11, 11A, 11B) is fastened by means of an adhesive (39). Heat shield brick (1) according to claim 7,
characterized in that the tension element (11, 11A, 11B) has a channel (41) into which the adhesive (39) for anchoring the tension element (11, 11A, 11B) can be introduced. Heat shield brick according to one of the preceding claims,
characterized in that a further tension element (11B) is provided, which is attached to the peripheral side (7) and lies opposite the tension element (11A). Heat shield brick (1) according to one of the preceding claims, characterized in that it consists of a ceramic base material (49), in particular of a refractory ceramic. Use of a heat shield brick (1) according to one of the preceding claims in a combustion chamber of a gas turbine.

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