EP2236928A1 - Heat shield element - Google Patents

Abstract

The element (1) has a heat shield plate (10) mounted on a carrier plate (5), where a hot side of the heat shield plate and a cold side of the carrier plate are mounted on a support structure. A through hole (11) mounts the shield plate on the carrier plate. A recess is provided in the carrier plate at a position corresponding to the through hole, and a mounting screw (2) is inserted through the through hole. Head of the screw is captured in a space formed by the recess, and a side of the shield plate faces the carrier plate. An independent claim is also included for a method for assembling a heat shield element.

Description

The invention relates to a heat shield element of a heat shield, a heat shield to a support structure, a use of the heat shield for turbine engines and a method of assembling the heat shield element with the features mentioned in the preambles of each independent claims.

In many technical applications, powerful ceramic heat shields are used to withstand temperatures between 1000 and 1600 degrees Celsius. In particular, the heat shields of turbine engines such as gas turbines and turbine engines, such as those used in power-generating power plants and in larger aircraft, have correspondingly large shielded by heat shields surfaces inside their combustion chambers. Because of the thermal expansion and large dimensions, the shield must be composed of a plurality of individual ceramic heat shield elements spaced apart from one another with sufficient clearance. This gap provides the heat shield elements with sufficient space for thermal expansion. However, since the gap also allows direct contact of the hot combustion gases with the support structure carrying the heat shield, a cooling fluid in the form of cooling air is blown through cooling passages as an effective countermeasure through the gaps in the direction of the combustion chamber. This cooling air is also used to selectively blow the metal brackets, with which the ceramic heat shield elements (CHS, Ceramic Heat Shields) are clamped to the support structure, and thus to cool. In still further improved arrangements, cooling air is also injected below the ceramic heat shield elements to allow cooling of the underside.

In order to carry out the brackets as simply and integrally as possible, a construction is known in which these brackets on the one hand in the support structure encircling parallel recessed grooves are inserted and clamped on the other hand with trained gripping portions with holder grooves, in which are formed in the side surfaces of the ceramic heat shield elements. The heat shield elements are successively inserted with the holders in the grooves of the support structure, wherein the trailing elements obstruct the previously positioned in their positions. In this way, for example, a circular series of heat shield elements can be formed in a combustion chamber of a gas turbine.

However, the last remaining heat shield element can no longer be mounted in this way because the mutually present adjacent heat shield elements block a tangentially directed assembly movement. Often, such a last heat shield element is referred to as dummy stone or dummy. Consequently, solutions are used with screws for attaching the last heat shield element, which allow mounting in the direction of the surface normal of the support structure. A known screw used for this purpose four screws which engage in recesses which are formed in the side surfaces of the heat shield element for this purpose. This solution is often disadvantaged because on the one hand, the four screws require additional cooling and thereby more cooling air consumption and on the other hand, the assembly brings a handling problem with it. The handling of the four screws, for example, enforces the use of fixatives such as bonding or adhesive tape, which are not reliable, so that the screws can be lost and must necessarily be found because of high risk of damage. Furthermore, no overhead mounting is possible, so that a considerable amount of time to position a large turbine assembly in the appropriate easy-to-assemble 6 o'clock position of the mounting station. In addition, it may be necessary for two people to install the last heat shield element as the four screws must be inserted into the corresponding four holes in the support structure. Last but not least is to consider that the screws are relatively expensive because of the highly heat-resistant alloy used and must be replaced with new ones at each dismantling because of high safety requirements.

EP 1 701 095 A1 and EP 0 558 540 B1 describe by way of example a heat shield as described above with the described advantages and disadvantages. The heat shield elements are often referred to as stones and retaining elements holding them stone holder.

The object of the present invention, in view of the above-described disadvantages in the prior art, is to make a heat shield member mountable as a last one of a plurality of heat shield members of a heat shield, thereby having few mounting members and the heat-protective function, as well as the cooling fluid circulation remain.

According to a first aspect, the invention is directed to a heat shield element for a heat shield having a plurality of heat shield elements arranged adjacently to a support structure, the heat shield element having a hot side and a cold side.

The objects according to the invention are achieved according to this aspect in that the heat shield element has a heat shield plate forming the hot side and a carrier plate forming the cold side, wherein the heat shield plate can be mounted on the carrier plate. This makes it possible to divide the attachment of the last heat shield element to the support structure in an attachment of the support plate to the support structure and a fastening of the support plate to the heat shield plate and to make correspondingly advantageous. Preferably, the heat shield plate forming the hot side is made of a heat-resistant sintered or ceramic material and the support plate forming the cold side is formed of a metallic material or a metal alloy.

It is advantageous if at least one through hole in the heat shield plate is provided for mounting the heat shield plate on the support plate, wherein the position of this through hole in the surface of the heat shield plate is provided substantially as a symmetrical position. This one hole is sufficient to press through a screw. In this case, the transverse dimension of the throughbore is preferably smaller than the diameter of the head of a fastening screw which can be inserted into the carrier plate.

In the carrier plate according to a particularly preferred embodiment of the present invention, a recess provided with a through hole in a corresponding hole for piercing the heat shield plate, in which the fastening screw is pushed, the head of the fastening screw in a through the recess and the carrier plate facing side the heat shield plate trained space is locked. As a result, the fastening screw can not be lost.

The heat shield plate preferably has a respective receiving groove located in the two mutually opposite and opposite lateral edges, which are provided for engagement of the holding elements by gripping portions.

In order to receive and hold the holding element, the carrier plate has at least one groove which has a common groove base and a narrowed region forming the open groove side.

Further advantages can be achieved with an embodiment according to the invention, when the carrier plate and the heat shield plate with each other by means of at least two holder elements wherein the retaining element comprises means for engaging in the holder grooves of the heat shield plate and means for engaging in the grooves of the carrier plate.

The means formed in the holding element for engaging in the holder grooves of the heat shield plate are preferably designed as gripping sections.

The formed in the holding element means for engaging in the grooves of the support plate are further preferably formed as a widened shoe whose width corresponds to the width of the common groove bottom of the groove of the support plate.

The holding element may further comprise a fixing portion serving as a retaining spring, the width of which corresponds to the width of the narrowed portion of the groove of the carrier plate.

The thickness of the heat shield plate and the thickness of the support plate preferably give a total thickness of the two-part heat shield element according to the invention, which corresponds to the thickness of a one-piece ceramic heat shield element.

According to a second aspect, the objects of the invention are achieved with a heat shield on a support structure comprising a plurality of heat shield elements, with at least one heat shield element according to a previously described embodiment.

For this purpose, the heat shield element according to the invention is provided as a last, a series of pre-mounted adjacent heat shield elements final heat shield element.

According to the invention, the objects of the invention can also by a use of the heat shield with at least one heat shield element according to one of the previously described embodiment for the production of a combustion plant or a Turbine engine to be solved, wherein the turbine engine may be designed in particular as a gas turbine.

According to a procedural aspect, a method for assembling a heat shield element according to one of the previously described preferred embodiments is used to achieve the objects according to the invention.

• die Befestigungsschraube in die in der Vertiefung vorgesehene Bohrung eingeführt wird,
• die Hitzeschildplatte mithilfe von wenigstens zwei Halteelementen, die mit ihrem jeweiligen Schuh in die Nuten der Trägerplatte eingeführt werden, mit der metallichen Trägerplatte durch Eingriff mittels der Greifabschnitte der Halteelemente in die in den einander abgewandt liegenden Kanten der Hitzeschildplatte vorgesehene Halternuten verklammert werden.

This method according to the invention is preferably characterized in that

• the fixing screw is inserted into the hole provided in the recess,
• the heat shield plate by means of at least two holding elements, which are introduced with their respective shoe in the grooves of the support plate, with the metallic support plate by engagement by means of the gripping portions of the holding elements in the provided in the opposite edges of the heat shield plate holder grooves are clamped.

The method according to the invention provides further advantages if at least one holding element is fastened non-positively to the carrier plate at the attachment opening, the holding element opposite this at least one attached holding element being left unattached.

According to an embodiment as a so-called pocket CHS (pocket stone) is possible.

As a result, it is possible according to the invention to produce a heat shield element, which is mounted in a straightforward manner as the last element of a heat shield, as a so-called dummy and in this case both the heat protection and the cooling of the metallic support members and support plate is ensured by cooling air.

Further preferred embodiments of the invention will become apparent from the remaining, mentioned in the dependent claims characteristics.

In addition, other features, features and advantages of the invention will become apparent from the following description of the embodiments with reference to the accompanying drawings.

Figur 1

eine Teilquerschnittsansicht durch eine bevorzugte Ausgestaltung des erfindungsgemäßen Hitzeschildele- mentes,

Figur 2

eine Seitenansicht auf das erfindungsgemäße Hitze- schildelement,

Figur 3

eine perspektivische Ansicht des erfindungsgemäßen Hitzeschildelementes,

Figur 4

eine perspektivische Ansicht der Tragstruktur,

Figur 5

eine perspektivische Ansicht des Halteelementes,

Figur 6

eine vergrößerte perspektivische Teilansicht des erfindungsgemäßen Hitzeschildelementes im Bereich eines Halteelementes.

The invention will be explained below in embodiments with reference to the accompanying drawings. Show it:

FIG. 1

1 is a partial cross-sectional view through a preferred embodiment of the heat shield element according to the invention,

FIG. 2

a side view of the heat shield element according to the invention,

FIG. 3

a perspective view of the heat shield element according to the invention,

FIG. 4

a perspective view of the support structure,

FIG. 5

a perspective view of the retaining element,

FIG. 6

an enlarged partial perspective view of the heat shield element according to the invention in the region of a holding element.

FIG. 1 shows a partial cross-sectional view through a preferred embodiment of the heat shield element 1 according to the invention.

The heat shield element according to the invention is designed in two parts and has a preferably ceramic heat shield plate 10 and a preferably metallic support plate 5. The total thickness of both plates is chosen to be equal to the thickness of a standard all-ceramic one-piece heat shield element to form a uniformly thick heat shield.

The support plate preferably has a fixing device which is substantially axially symmetrical in its center and which consists of an extension 3 projecting toward the cold side 4 and a depression 12 which is perforated by a bore. In this mounting hole, a fixing screw 2 can be introduced.

Both plates are clamped together by means of preferably resilient metal holders 7 (see FIGS. 5 and 6 ), wherein the holder 7 engages with its gripping portion 21 in a lateral holder groove 8 of the heat shield plate 10.

The heat shield plate 10 has a through bore 11, which is arranged exactly above the fastening screw 2. Through this through hole 11, an assembly tool (not shown) can be inserted therethrough to engage in the head of the screw 2 and rotate it, when the heat shield element is attached to a support structure. The diameter of the through hole 11 is selected such that the assembly tool, for example a screwdriver or an Allen wrench, just passes freely through. Thereby, the diameter of the through hole 11 can be kept as small as possible, whereby less heat can penetrate into the bore of the hot side 9 and cause a heat problem there.

However, since the head of the fixing screw 2 is much larger than the through hole 11, the fixing screw 2 must be inserted into the fixing hole of the recess 12 before the support plate 5 and the heat shield plate 10 are clamped together by means of the holders 7. After this is done, the mounting screw 2 is in a lock space between the two plates and thus can not be lost.

FIG. 2 shows a side view of the heat shield element 1 according to the invention, compared to the view in FIG. 1 turned 90 degrees.

In this view, it can be seen how the retaining element 7 is embedded in the support plate 5. The intended for receiving the retaining element 7 groove 6 of the support plate 5 is formed in a projecting toward the cold side Vorstreckung This Vorsteckung 13 forms a guide rail 13, preferably one on each side of the support plate 5, which is inserted into the respective groove 15 of the support structure 16 and the support plate 5 with the mounted on her heat shield plate 10 allows accurate positioning and alignment. The grooves 15 in the support structure 16 need not be introduced specifically for the heat shield element 1 according to the invention in the support structure, but are usually already provided for the assembly of the normal one-piece ceramic heat shield elements using the identical holding elements 7.

FIG. 3 shows an overall perspective view of the heat shield element 1 according to the invention, which has a ceramic heat shield plate 10 and a metallic support plate 5.

The ceramic heat shield plate 10 and the metallic support plate 5 are preferably held together by four retaining elements 7. In another embodiment, the number of holders 7 may be reduced to at least two, one from each side. For this purpose, the holders 7 engage in the holder grooves 8 provided in the two oppositely facing edges of the heat shield plate 10. A detail of this attachment is in the FIGS. 5 and 6 specified. Here, the holder 7 of the same type as conventional for mounting the one-piece ceramic heat shield elements, z. As the adjacent, are used, however, are mounted in contrast to a positioned between the heat shield plate 10 and the support structure 16 metallic support plate 5.

The through hole 11 serves as described above for inserting a narrow mounting tool to screw the fixing screw 2 in the support structure 16, where either a thread is present or a lock nut is positioned.

In FIG. 4 is a perspective view of the support structure 16, for example, a turbine engine, shown.

The support structure 16 has parallel grooves 15, in which the one-piece ceramic heat shield elements are clamped one behind the other by means of the resilient metallic holder 7. Preferably, the last piece of the heat shield is formed with the two-part heat shield element 1 according to the invention.

For this purpose, a bore 22 is provided in the support structure 16 exactly at the location of the last heat shield element into which the protruding extension 3 of the metallic support plate 5 of the heat shield element is fitted. At the same time the two parallel arranged and correspondingly sized Vorstreckungen 13 are arranged in the parallel arranged, possibly widened grooves 15 of the support structure 16, so that the two-part heat shield element 1 according to the invention assumes a precisely predetermined position on the support structure 16.

The support structure 16 may further include, in preferred embodiments, cooling apertures 23 connected to cooling air passages.

The surface of the support structure 16 may be flat or curved. Furthermore, the curvature can be formed both convex and concave.

The preferred determination of the two-part heat shield element 1 according to the invention is as a final element of the heat shield in a consequent mounting direction, the essentially follows the normal to the surface of the support structure provided. However, it may be provided in terms of easier access and reduced effort to replace a defective heat shield element to provide multiple termination points in a heat shield row. Then not all heat shield elements in a row need to be removed to replace only a few elements.

Furthermore, the two-part heat shield element 1 according to the invention enables simple assembly by a person and only from one side of the installation if a thread device or a thread for the fastening screw 2 is provided in the support structure 16.

FIG. 5 shows a holding element 7 in a perspective view. The retaining element 7 is preferably made of metal and comprises a fastening section 18, also called a retaining spring, with which the retaining element 7 can be fastened to a support structure 16 of a combustion chamber wall, for example the combustion chamber wall of a gas turbine plant.

The holding elements 7 are guided on the support plate 5 in each case a groove 6 (see. Fig. 6 ).

Here engages a widened portion of the mounting portion 18, the so-called shoe of the retaining element 7, closely tolerated in a parallel to the surface of the support plate 5 embedded (for example, about 10 mm deep) groove 6 a. Such attachment of the one-piece ceramic-made normal heat shield elements to a support structure 16 is known. According to the invention, this known fastening method is now applied to a support plate 5 serving as an intermediate element. As a result, the advantages of a proven method of attachment according to the invention are maintained.

The groove 6 is designed so that it has the required width for inserting the shoes width only in the groove base. When pulling up the holding element 7 in the groove 6 this supports at the narrow region of the groove 7, whereby a holding element 7 holding holding force is mediated. The non-widened part of the attachment portion 18 can thereby be lifted freely in the groove 6. The attachment opening 17 in the shoe serves to fix all or some holding elements 7 in the groove, which can be done from the cold side of the support plate 5 by means of pins, Arretiermaden or screwing. Usually, a heat shield element is held on two opposite sides of two holding elements 7, that is, a total of four holding elements 7.

The attachment portions 3 of the holding elements 7 arranged on the other side are not secured in a preferred embodiment, so that they can slide in order not to hinder the thermal expansion of the heat shield element.

At that end of the retaining spring 18, which is opposite to the end with the attachment opening 17, a holder head 20 is formed. This holder head 20 has a section 19, which is angled substantially at right angles to the retaining spring 18, and a gripping section 21, which in turn is angled substantially perpendicular to the section 19. The gripping portion 21, also called the gripping tab, is used to engage in the groove of a heat shield element. A heat shield element can be clamped by engagement of gripping tabs 21 of holding elements 7, which are fixed to a support plate 5, in the holder grooves 8 opposite sides of the heat shield plate 10 with the support plate (see Fig. 6 ).

FIG. 6 shows an enlarged partial perspective view of the heat shield element 1 according to the invention in the region of a holding element. 7

The ceramic heat shield plate 10 shown above with the hot side 9 is in this case arranged on the arranged below it metallic support plate 5 and with the under FIG. 5 described holding element 7 clamped. The groove 6 of Support plate 5 in this case has a wider groove bottom and a narrow portion 14 through which the retaining spring 18 of the retaining element 7 can escape while the shoe is retained with the mounting hole 17.

Claims (17)

A heat shield element (1) for a heat shield having a plurality of heat shield elements arranged adjacently to a support structure (16), the heat shield element (1) having a hot side (9) and a cold side (4),
characterized in that
the heat shield element (1) has a heat shield plate (10) forming the hot side and a carrier plate (5) forming the cold side, wherein the heat shield plate (10) can be mounted on the carrier plate (5). Heat shield element (1) according to claim 1,
characterized in that
the heat shield plate (10) forming the hot side is formed of a heat resistant sintered or ceramic material. Heat shield element (1) according to any preceding claim,
characterized in that
the cold side forming support plate (5) is formed of a metallic material or a metal alloy. Heat shield element (1) according to any preceding claim,
characterized in that
for mounting the heat shield plate (10) on the support plate (5) at least one through hole (11) in the heat shield plate (10) is provided, wherein the position of this through hole (11) in the surface of the heat shield plate (10) substantially as a symmetrical position is provided. Heat shield element (1) according to claim 4,
characterized in that
the transverse dimension of the throughbore (11) is smaller than the diameter of the head of a fastening screw (2) which can be inserted into the carrier plate (5). Heat shield element (1) according to claim 5,
characterized in that
in the support plate (5) at a position corresponding to the through hole (11) of the heat shield plate (10) a recess (12) is provided with a through bore into which the fastening screw (2) can be inserted, wherein the head of the fastening screw (2) in a space formed through the depression (12) and the side of the heat shield plate (10) facing the support plate (5) is locked. Heat shield element (1) according to any preceding claim,
characterized in that
the heat shield plate (10) in each case has a receiving groove (8) lying in the two opposite lateral edges facing away from each other and provided for engagement of the holding elements (7) by gripping portions (21). Heat shield element (1) according to any preceding claim,
characterized in that
the carrier plate (5) has at least one groove (6) which has a common groove base and a narrowed region (14) forming the open groove side. Heat shield element (1) according to any one of the preceding claims 7 to 8,
characterized in that
the support plate (5) and the heat shield plate (10) are clamped together by at least two holder elements (7), the holding element (7) having means for engaging the holder grooves (8) of the heat shield plate (10) and means for engaging the grooves (6) of the carrier plate (5). Heat shield element (1) according to any one of the preceding claims 7 to 10,
characterized in that
formed in the holding element (7) means for engaging in the holder grooves (8) of the heat shield plate (10) are designed as gripping portions (21). Heat shield element (1) according to any preceding claim,
characterized in that
formed in the holding element (7) means for engaging in the grooves (6) of the support plate (5) are formed as a widened shoe whose width corresponds to the width of the common groove bottom of the groove (6) of the support plate (5). Heat shield element (1) according to any preceding claim,
characterized in that
the retaining element (7) has a fastening section (18) which serves as a holding spring (18) and whose width corresponds to the width of the narrowed region (14) of the groove (6) of the carrier plate (5). Heat shield element (1) according to any preceding claim,
characterized in that
the thickness (a) of the heat shield plate (10) and the thickness (b) of the support plate (5) give a total thickness (c) corresponding to the thickness of a one-piece ceramic heat shield element. A heat shield on a support structure (16) comprising a plurality of heat shield elements, comprising at least one heat shield element (1) according to any preceding claim,
characterized in that
the heat shield element (1) is provided as a last, a series of pre-mounted adjacent heat shield elements final heat shield element. Use of the heat shield with at least one heat shield element according to one of the preceding claims for the production of a combustion plant or a turbine engine, wherein the turbine engine is implemented as a gas turbine or a liquid fuel turbine. Method for assembling a heat shield element (1) according to one of the preceding claims,
characterized in that - the fixing screw (2) is inserted into the hole provided in the recess (12), - The heat shield plate (10) by means of at least two holding elements (7), which are inserted with their respective shoe in the grooves (6) of the support plate (5) with the metallic support plate (5) by engagement by means of the gripping portions (21) Retaining elements (7) in the mutually remote in the opposite edges of the heat shield plate (10) provided Halutenuten (8) are clamped. Method according to claim 16,
characterized in that
at least one holding element (7) with the support plate (5) is fastened non-positively to the attachment opening (17), wherein the at least one fixed holding element (7) opposite holding element (7) is left unattached.

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