Patent Application
20080050225
The invention relates to a heat accumulation segment for the local separation of a flow duct inside a turbo engine, in particular a gas turbine system, from a stator housing that radially surrounds the flow duct, having two axially opposed joining contoured elements that may respectively be brought into engagement with two components that are axially adjacent along the flow duct.
Heat accumulation segments of the type indicated above are parts of axial-flow turbo engines, through which there are flow working media, which are gaseous for the purpose of compression or controlled expansion, and which as a result of their high process temperatures put those system components that are directly acted upon by the hot working media under considerable thermal load. In particular in the turbine stages of gas turbine systems, the rotor blades and guide blades, which are arranged axially one behind the other in rows of rotor blades and guide blades, are directly acted upon by the combustion gases produced in the combustion chamber. To prevent the hot gases that flow through the flow duct from also reaching regions inside the turbo engine that are remotely located from the flow duct, so-called heat accumulation segments that are provided on the stator side, in each case between two rows of guide blades arranged axially adjacent to one another, ensure that there is a bridge-like seal, which is as gas-tight as possible, between the two axially adjacent rows of guide blades.
Heat accumulation segments of corresponding construction may also be provided along the rotor unit. These segments are to be mounted on the rotor side, in each case between two axially adjacent rows of rotor blades, in order to protect regions inside the rotor from excessive heat input.
Although the statements below refer exclusively to heat accumulation segments arranged between two rows of guide blades, and to this extent make it possible to separate the housing on the stator side and the components associated therewith from the flow duct, which is subject to heat load, and to protect them accordingly, it is also conceivable to provide the measures below in a heat accumulation segment that serves to protect entrained rotor components and that is intended for mounting between two rows of rotor blades arranged axially adjacent to one another.
An arrangement of guide blades that is known per se and has an integrated heat accumulation segment can be seen from the partial longitudinal sectional illustration of
The flow duct K′ is delimited radially externally by guide blades 104 that are mounted on the stator side and whereof the guide blade vanes 141 project radially outward into the flow duct K′. In order to separate the flow duct K′ in gas-tight manner from the components mounted on the stator side, the guide blades 104 have a platform 142 which, in the form of a one-part component, covers the axial region directly around the guide blade vane 141 and, in the form of a balcony-like overhang 142′, covers the region that bridges two rows of guide blades and radially opposes each of the guide blade tips.
Because the guide blades 104 are arranged in the peripheral direction of the gas turbine, in respective rows of guide blades, the guide blades 104 within a guide blade row that are in each case arranged directly adjacent in the peripheral direction have to be connected to one another in gas-tight manner along their axial side edges 105. To achieve the gas-tight sealing, a tape seal 106 runs over the entire extent of the side edge 105 and opens on either side into corresponding grooves along the side edges of two adjacent guide blades. The tape seal 106 ensures in particular that no cooling air that is supplied to the platform 142 on the stator side can escape into the flow duct K′, and therefore corresponding cooling ducts inside the guide blade are available for the effective cooling of all the guide blade regions exposed to the hot gases.
However, everyday operation of gas turbine systems shows that all the components of the gas turbine stage are exposed not only to heat loads but also to mechanical vibrations, as a result of which for example the guide blades 104 are also subjected to tiny radial and axial movements and jolting, and a not inconsiderable result of this is that the tape seals mounted between the guide blades are also weakened. Thus, in the course of mechanical vibrational loads inside the tape seals, cracks and fractures are produced, as a result of which the seals start to become very crumbly. In the event of seal damage of this kind, considerable losses may occur due to leakage between the individual guide blade segments, such that the cooling of the individual guide blades that is required for safe operation cannot be sufficiently guaranteed.
To meet this need, maintenance and inspection work has to be carried out regularly on the guide blades and on the sealants provided in this region. However, this work requires complete rows of guide blades to be dismantled in order ultimately to replace tape seals that are provided between two adjacent guide blades in a guide blade row.
It can be seen, from the joining connection between a guide blade 104 and a stator-side support structure 107 supporting the latter, which can be seen from the longitudinal sectional illustration in
The object of the invention is to effectively counter the above-described phenomena of wear that arise as a result of mechanical vibrations at the tape seals that are provided between two guide blades. The intention is to make the maintenance intervals required for the inspection of these seals considerably longer. At the same time, the complexity of the assembly and dismantling that is required for the inspection and where appropriate for the replacement of corresponding sealing materials should be markedly reduced. In particular, it should not be necessary, when removing individual guide blades from the assembly comprising a row of guide blades, to dismantle the entire guide blade row or at least segment regions of the guide blade row.
The present invention is a heat accumulation segment for local separation of a flow duct inside a turbo engine, from a stator housing that radially surrounds the flow duct. The heat accumulation segment includes two axially opposed joining contoured elements that are engagable with two components that are axially adjacent along the flow duct. A first one of the two joining contoured elements has a radially oriented recess with a contoured surface against which a securing pin having an external contour complementary to the contoured surface acts radially under force action from a component that adjoins the first joining contoured element. The first joining contoured element has a collar portion having radially upper and lower collar surfaces, and the collar portion is connected within a counter-contoured receiving contoured element in the axially adjacent component by a joining force that acts between the securing pin and the conical contoured surface.
The invention will be described by way of example below, without restricting the general concept of the invention, and by way of exemplary embodiments with reference to the drawing, in which:
a shows a longitudinal sectional illustration through a guide blade heat segment arrangement,
b shows a detail illustration of the joining connection, and
The concept underlying the invention takes as its basic starting point separation of the guide blade platform 142 and the balcony-shaped platform section 142′, which in accordance with the illustration presented in
The construction of a heat accumulation segment of this kind as a separate component from the guide blade helps to reduce to a marked extent the damaging effects of the operation-dependent radial and axial jolting of the tape-type sealants that are inserted in each case between peripherally adjacent guide blades, the more so if the axial extent of the respective tape seal is divided in half and runs separately along the side edge of the guide blade platform and the heat accumulation segment.
Moreover, the heat accumulation segment that is constructed as a separate component is to be inserted between two axially adjacent guide blades such that individual guide blades can be removed individually from the assembly comprising a row of guide blades, that is to say without the need to dismantle a complete guide blade row.
A heat accumulation segment of this kind, which in principle serves for local separation of a flow duct inside a turbo engine, in particular a gas turbine system, from a stator housing that radially surrounds the flow duct, and having two axially opposed joining contoured elements that may respectively be brought into engagement with two components that are axially adjacent along the flow duct, such as in particular two guide blades, is constructed in accordance with the invention in that a first one of the two joining contoured elements has a radially oriented recess with a contoured surface against which a securing pin having an external contour acts radially under force action from a component that adjoins the first joining contoured element. Furthermore, the first joining contoured element has a collar portion having a radially upper collar surface and a radially lower collar surface, and the collar portion is connected within a counter-contoured receiving contoured element in the axially adjacent component by a joining force that acts between the securing pin and the contoured surface.
The securing pin preferably has a cylindrical external contour which comes into operative connection with the contoured surface of the recess. This is therefore a so-called cylindrical securing pin which can be pressed flush against a correspondingly inversely-contoured cylindrical contoured surface and ensures a secure fit of the heat accumulation segment against the adjoining component.
The above-described joining connection according to the invention, between a heat accumulation segment and an axially adjoining component of a turbo engine, is suitable in a particularly advantageous manner for use between two guide blades along a gas turbine stage. Although the other embodiments, which are made with reference to the exemplary embodiment, are restricted to a purpose of this kind, the joining connection according to the invention for the heat accumulation segment may equally well be applied between two axially adjacent rotor blades of a rotor unit. For this, the only proper adjustments that are required are construction-dependent and may be carried out by a person skilled in the art.
As is apparent below with reference to the exemplary embodiment presented, the heat accumulation segment according to the invention is detachably and firmly connected to an axially adjacent guide blade by way of only a single joining region. A second joining region of the heat accumulation segment, which lies axially opposite this joining region, is by contrast pressed loosely against a radially oriented joining surface on a stator-side support structure merely under the action of force. If the heat accumulation segment is to be removed, then the guide blade that is in contact with the heat accumulation segment can be separated by way of the loose press connection, merely by removing it axially. The heat accumulation segment may easily be separated from the other guide blade, by contrast, by detaching the joining connection, in that the guide blade concerned is removed from the support structure on the stator side, which supports the guide blade, in the peripheral direction, as a result of which the joining connection to the heat accumulation segment is detached automatically. Because the heat accumulation segment according to the invention is distinguished by particular constructional features relating to the construction of the joint or connection, the heat accumulation segment according to the invention is described below with reference to a preferred exemplary embodiment.
a shows a partial longitudinal sectional illustration through the stator-side suspension of a guide blade 4 and a heat accumulation segment 12, the latter being constructed separately from the guide blade 4. As in the exemplary embodiment according to
Similarly, running along the side edge 5 of the guide blade 4 and along the side edge 13 of the heat accumulation segment 12 is, in each case, a tape-type sealant 6, 14, and these are in engagement with a heat accumulation segment, which is arranged adjacent in the peripheral direction, and a guide blade respectively, thereby ensuring a gas-tight seal between the flow duct K and the stator-side components 2. In particular, the space E, which is enclosed on the stator side by the heat accumulation segment 12 and is supplied with cooling air by way of a cooling air duct 15, is to be sealed off in largely gas-tight manner from the flow duct K in which in each case rotor blades La rotate axially between adjacent guide blades. Only for the sake of completeness should it be pointed out that the guide blade 4 is also supplied with cooling air. The cooling air supplied in this region is also sealed off from the flow duct K, which is ensured by the tape seal 6.
In contrast to the example described in the background, having a one-piece continuous tape seal, the present invention provides tape seals 6 and 14 of the guide blade and the heat accumulation segment 12, which are each constructed separately. Since they are only half as long, the wear caused by vibrations, which occur as a result of material abrasion, occurs to a markedly lesser extent. This makes it possible to markedly increase the maintenance, and in some cases the replacement, intervals for the tape seal.
In order to reduce the complexity of assembly and dismantling for maintenance work, the heat accumulation segment 12 is constructed separately. The heat accumulation segment 12 has a joining connection, which is constructed according to the invention, with the axially adjacent guide blades, as a result of which it is possible to remove them from the overall assembly of the gas turbine arrangement easily, quickly and in particular individually.
As a basic requirement, the heat accumulation segment 12 constructed in accordance with the invention has two axially opposed joining contoured elements 17, 18, of which the joining contoured element 18 is pressed against a surface region 20 of the stator-side support structure 7 merely by the action of force through a radially oriented joining surface 19. To separate the internal cooling space E from the flow duct K in gas-tight manner, there is provided inside the radially oriented joining surface 19 a groove-shaped recess inside which a sealant 21 is applied. Furthermore, the second joining region 18 adjoins, via a further axial joining surface 22, an axially adjacent guide blade 4′, which, when it is to be assembled and dismantled, can be assembled and dismantled only by displacing it axially closer to the heat accumulation segment 12 and moving it axially away therefrom. Provided axially opposite the joining region 18 is the first joining region 17, which is shown on a larger scale in the illustration presented in
The joining region 17 of the heat accumulation segment 12 has a collar portion 23 that provides a radially upper and a radially lower collar surface 24, 25. In this arrangement, the collar portion 23 projects axially into a correspondingly counter-contoured receiving contoured element 26 inside the axially adjacent guide blade 4. The connection between the collar portion 23 and the receiving contoured element 26, which to be more precise is provided in the root region of the guide blade 4, is made with precise fit, with the result that the joint or connection has no play or tolerance, at least in the radial direction. This is particularly necessary for a gas-tight press fit, made under the action of force, of the axially opposed joining contoured element 18 against the support structure 7 in the surface region 20.
Directly adjoining the collar portion 23 in the axial direction, the joining contoured element 17 has a radially oriented recess 27 having a cylindrical contoured surface 28. The radially oriented recess 27 has a half shell form, with the cylindrical contoured surface 28 mounted axially facing the collar portion 23.
The joining region 17 is additionally covered, radially externally, by an overhanging region 29 of the guide blade 4, and the guide blade 4 is secured in a stator-side support structure 7 by this overhanging region 29. An opening 30 which completely radially penetrates the overhanging region 29 is made in the overhanging region 29 of the guide blade 4, and a cylindrical securing pin 31, a spring element 32 and a screw-type bearing element 33 are provided therein. The securing pin 31 has a cylindrical external contour 34 that comes into engagement with the contoured surface 28 of the first joining contoured element 17 when the securing pin 31 is lowered radially. In the joined condition of the guide blade 4, that is to say as soon as the overhanging region 29 comes into contact with the support structure 7, the bearing element 33 is pressed radially inward in opposition to the spring force of the spring element 32, as a result of which the securing pin 31 is pushed radially inwardly against the cylindrical contoured surface 28 of the radially oriented recess 37. As a result of this, the collar portion 23 of the joining region 17 is compressed axially into the recess 26 in the root region of the guide blade 4. This joining connection, which is held exclusively by the spring-loaded securing pin 31, which for its part is secured by the joining connection between the overhanging region 29 and the stator-side support structure 7, produces a stable and yet easily detachable connection between the heat accumulation segment 12 and the axially adjacent guide blade 4.
It is therefore possible to replace the guide blade 4′ from a closed gas turbine arrangement in the following way: as already mentioned above, the guide blade 4′ may be dismantled by removing it axially. Even with the guide blade 4′ removed, the heat accumulation segment 12 remains in its predetermined place, the more so since the heat accumulation segment 12 is kept automatically supported against the root of the guide blade 4 by the joining connection described above in accordance with the invention. Thus, the heat accumulation segment 12 is prevented from slipping axially by the contact between the securing pin 31 and the contoured surface 28 of the joining region 11. Similarly, the tolerance-free joining at the upper and lower collar surfaces 24, 25 inside the counter-contoured receiving contoured element 26 ensures that there is sealing under force action in the region of the second joining region 18, as described above. The presence of the heat accumulation segment 12 does not hinder re-assembly of the guide blade 4′. Rather, it is possible to bring the guide blade 4′ into contact with the second joining region 18 by bringing it axially closer in accordance with the movement vector G.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102005013796.2 | Mar 2005 | DE | national |
This application is a continuation of International Application No. PCT/EP2006/060900 filed Mar. 21, 2006, which is incorporated by reference as if fully set forth.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2006/060900 | Mar 2006 | US |
| Child | 11860099 | Sep 2007 | US |
