WIRE SEAL
The disclosure concerns a wire seal for sealing a gap between two components of a gas turbine, the wire seal including a first core and a second core spaced apart from one another, a wire pack extending around the first core and the second core, and a fastener for securing the wire pack to the first core and the second core, wherein the wire seal is curved. Various embodiments are disclosed, including various types of fastener. A method of manufacturing a wire seal is also disclosed.
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The present disclosure relates to wire seals, and particularly to wire seals for sealing a gap between a picture frame and a first vane of a gas turbine.
BACKGROUND OF THE INVENTIONIn a gas turbine, there is a sealing interface between combustor outlet and the first vane of the turbine. Movement of the two parts relative to one another can be considerable, and a gap must be left between the parts to avoid contact. The gap is generally purged with cooling air. It has been appreciated that it would be advantageous to improve the design around this gap to, for example, reduce the cooling air requirements.
SUMMARY OF THE INVENTIONThe invention is defined in the appended independent claims to which reference should now be made. Advantageous features of the invention are set forth in the dependent claims.
A first aspect of the invention provides a wire seal for sealing a gap between two components of a gas turbine, the wire seal comprising a first core and a second core spaced apart from one another, a wire pack extending around the first core and the second core, and a fastener for securing the wire pack to the first core and the second core, wherein the wire seal is curved. The plate can provide extra sealing in addition to the wire pack, for example if a gap opens in the wire pack during use. The wire pack can help protect the plate, thereby increasing the lifetime of the plate in a high temperature environment. The wire seal can cope with the large relative axial and radial movements of the picture frame and first vane (first turbine vane).
In one embodiment, the wire seal comprises a plate with a first face, a second face, a first edge comprising the first core, a second edge comprising the second core and two end edges, wherein the first edge is opposite the second edge, wherein the wire pack extends around the first face, the first edge, the second face and the second edge of the plate, and wherein the fastener secures the wire pack around the plate. The plate can improve the seal.
In one embodiment, the fastener comprises a first clamp for securing the wire pack to the first core and a second clamp for securing the wire pack to the second core.
In one embodiment, the fastener comprises at least one end piece attached at each end first core and the second core, to hold the wire pack in place adjacent to the first core and the second core. In one embodiment, the fastener extends around the wire pack from the first core to the second core, to hold the wire pack in place adjacent to the plate. In one embodiment, the wire seal comprises a first core wire attached to the first edge and a second core wire attached to the second edge. In one embodiment, the wire seal is a conical wire seal. In one embodiment, the first core is a first core wire and the second core is a second core wire.
A second aspect of the invention provides a gas turbine comprising a wire seal as described above. In one embodiment, the gas turbine comprises a combustor and a first vane separated by a gap, and wherein the wire seal is arranged to seal the gap. Leakage reduction through this gap can thereby be achieved. In one embodiment, the combustor comprises a picture frame and wherein the gap is between the first vane and the picture frame. In one embodiment, the gas turbine comprises a socket in the picture frame, and wherein the wire seal is seated in the socket. This can hold the wire seal in place.
A third aspect of the invention provides a method of manufacturing a wire seal for sealing a gap between two components of a gas turbine, the wire seal comprising a first core and a second core spaced apart from one another, a wire pack extending around the first core and the second core, and a fastener for securing the wire pack to the first core and the second core, wherein the wire seal is curved, comprising the steps of placing the wire pack around the plate and fastening the wire pack to the plate with the fastener. In one embodiment, the wire pack is made of wire and is placed around the first core and the second core by winding the wire repeatedly around the first core and the second core.
An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings in which:
The first core wire 12 is attached to one edge (a first edge) of the plate 16 and the second core wire 14 is attached to the opposite edge (a second edge) of the plate 16. The wire pack 22 extends around the first and second core wires 12, 14 and the plate 16. The wire pack is held in place by a fastener, in this case the first and second clamps 18, 20. The first clamp extends around the portion of the wire pack closest to the first core wire, with the second clamp arranged in the same way close to the second core wire. As the plate is thinner than the diameter of the first and second core wires, the effective width (the width including the plate/core wires) of the cross-section of the wire pack 22 perpendicular to the plate 16 is greater at the core wires 12, 14 than in the main portion of the wire pack 22 at the plate 16.
In a gas turbine, a plurality of picture frames (sequential liner outlets) are arranged around the longitudinal axis of the gas turbine in a ring, with the picture frames typically being attached to sequential liners (combustor linings) and the sequential liners typically surrounding can combustors. The picture frames generally all intersect a plane perpendicular to the gas turbine longitudinal axis. The wire seal discussed in this application can be applied on either the inner or outer diameters of the picture frames (the edge of the picture frames closest to the gas turbine longitudinal axis). This can allow for single vane/blade assembly and/or disassembly during manufacture, maintenance and repair.
In
In a method of manufacturing a wire seal 10 as shown in
The wire that makes up the wire pack 22 is described above as being attached to another part of the wire seal before being wrapped around the plate, but one or both ends of the wire may be attached either before or after the wire is wrapped around the plate.
To manufacture the wire seal 10 as shown in
To manufacture the wire seal 10 as shown in
The wire seal 10 is described above as sealing the gap between a picture frame and a first vane of a gas turbine, but more generally the wire seal may also seal the gap between two components, for example between the first vane and another part of the combustor such as the combustor lining. The components to be sealed would normally both be static (static-to-static sealing).
The wire seal 10 may be straight as shown in the small portions shown in
The wire seal can be annular. In the case of an annular wire seal, the wire seal describes (a section of) a ring in which the first edge and the second edge are at the same distance from the gas turbine longitudinal axis (wire seal longitudinal axis); that is, the radius of curvature of the first edge and the second edge are the same. A radial wire seal could also be used, in which the second edge is further from the gas turbine longitudinal axis than the first edge and in the same plane perpendicular to the gas turbine longitudinal axis direction.
Preferably though, the wire seal is a conical wire seal. The conical wire seal has a second edge that is further from the gas turbine longitudinal axis than the first edge and in a different plane perpendicular to the gas turbine longitudinal axis direction.
For completeness, it is noted that a cone is a three-dimensional geometric shape that tapers smoothly from a flat base; the base may be circular or may be another shape. Mathematically, a conical wire seal is conical frustum, being in the shape of the surface of the frustum of a cone (i.e. a section of the cone not including the apex, also known as a truncated cone), in contrast to an annular wire seal in which the wire seal follows the shape of the surface of a cylinder.
The first and second core wires 12, 14 are optional, and one or both may be omitted, such as in the embodiments in
Although most of the plate 16 is not directly visible in the Figures, the plate 16 can be described in more detail as follows, with reference to
In embodiments comprising core wires, the plate is preferably thinner than the diameter of the first and second core wires, but in some embodiments the plate may be the same width as or wider than the diameter of the first and second core wires. The plate and the first and second core wires are described as separate components in the examples described above, but they may be one integrated component. The core wires may also be omitted entirely, as in the embodiments of
The attachment between the first and second core wires and the plate 16 can be a physical attachment such as a weld. Alternatively or additionally, a slot can be provided in the first and second core wires, and the plate is arranged in the slot. If a slot is provided, a physical attachment between the first and second core wires and the plate is optional, as the wire pack can hold the first and second core wires and the plate together.
The wire pack 22 may be made up of one or more wires repeatedly wound around the plate (and the first and second core wires in embodiments with core wires). Alternative wire packs are also possible; for example, a mesh or a chain could be wound around instead of a wire. The wire pack wire, mesh, chain or the like is typically attached at each end to stop it from unravelling, and can be attached to any appropriate part of the wire seal, for example a fastener, the plate or another part of the wire pack.
The wire pack is held on to the plate by a fastener or fasteners. Without appropriate fastening, the wire pack can unravel and/or slide off the end edges of the plate, and the clamps are designed to restrict the movement of the wire pack relative to the plate. The wire pack can also be fastened directly to the plate and/or to the clamps.
Various fasteners are described in this application, but other types of fastener and modifications to the described fasteners are possible. Any combination of the described fasteners is also possible in addition to those combinations already described. For example, the fasteners of the wire seals of
The first and second clamps 18, 20 can vary in shape but are each typically designed to encircle an end edge of the plate. The first and second clamps may be made as a spring so that the first and second clamps are in tension and are pushing on the wire pack to keep the wire pack against the plate. This can also help ensure that the first and second clamps do not slip off the wire pack, and may be particularly useful in cases without core wires. The first and second clamps could be attached to one another by one or more connecting bars extending across the surface of the wire pack (in the direction perpendicular to the first and second edges of the plate), in a similar manner to the connecting bar 74 between the central clamp end pieces 72 in the embodiment of
The end pieces 60 in the wire seal of
In embodiments with first and second core wires, the end pieces can be attached to the first and second core wires and/or the plate. The first and second core wires may extend beyond the end edges of the plate, in which case holes would be provided in the end pieces to connect with the first and second core wires. This could provide a better join between the first and second core wires and the end pieces. The end pieces may additionally be attached to the wire pack.
The diameter of the end pieces in the wire seals of
The first vane of the gas turbine may comprise one or more slots to accommodate the shape of fasteners such as end pieces 60. This can improve the seal and can also ensure that the wire seal remains in the correct place in the gap. In some of the embodiments the fastener contacts the first vane and/or the bulkhead/picture frame, and in other embodiments the wire pack contacts the first vane and/or the bulkhead/picture frame.
The central clamp 70 may be one integral part, or may be two or more parts. In the embodiment of
The picture frame 32, bulkhead 34 and first vane 30 may all vary in shape compared to the embodiments shown above, and the design can depend on variables such as the shape of the wire seal and the relative motion of the picture frame/bulkhead and the first vane.
The socket 38 in the picture frame/bulkhead is optional, and in some embodiments is not necessary. For example, a socket could alternatively be provided in the first vane to hold the wire seal in place. Sockets could also be provided on both the first vane and the picture frame/bulkhead. Other connecting components could also be provided to pivotally attach the wire seal to the first vane or the picture frame/bulkhead.
Typically, the gap is also purged with a cooling fluid such as cooling air, and there can therefore be a higher pressure on the side of the wire seal further from the hot gas path than on the side of the seal closer to the hot gas path. This pressure differential could hold the seal in place, and can also improve the quality of the seal.
The wire seals described herein are preferably for sealing gaps between two stationary parts, rather than gaps between a rotor and a stator.
Various modifications to the embodiments described are possible and will occur to those skilled in the art without departing from the invention which is defined by the following claims.
REFERENCE SIGNS10 wire seal
12 first core wire
14 second cord wire
16 plate
18 first clamp
20 second clamp
22 wire pack
23 first face
24 second face
25 first edge
26 second edge
27 end edge
30 first vane
32 picture frame
34 bulkhead
36 gap
38 socket
40 wire seal longitudinal direction (gas turbine longitudinal direction)
42 circumferential direction
60 end piece
70 central clamp
72 central clamp end piece
74 connecting bar
Claims
1. A wire seal for sealing a gap between two components of a gas turbine, the wire seal comprising:
- a first core and a second core spaced apart from one another,
- a wire pack extending around the first core and the second core, and
- a fastener for securing the wire pack to the first core and the second core, wherein the wire seal is curved.
2. The wire seal of claim 1, comprising:
- a plate with a first face, a second face, a first edge including the first core, a second edge including the second core and two end edges, wherein the first edge is opposite the second edge,
- wherein the wire pack extends around the first face, the first edge, the second face and the second edge of the plate, and
- wherein the fastener secures the wire pack around the plate.
3. The wire seal of claim 1, wherein the fastener comprises:
- a first clamp for securing the wire pack to the first core and a second clamp for securing the wire pack to the second core.
4. The wire seal of claim 1, wherein the fastener comprises:
- at least one end piece attached at each end of the first core and the second core, to hold the wire pack in place adjacent to the first core and the second core.
5. The wire seal of claim 1, wherein the fastener extends around the wire pack from the first core to the second core, to hold the wire pack in place adjacent to the plate.
6. The wire seal of claim 2, comprising:
- a first core wire attached to the first edge and a second core wire attached to the second edge.
7. The wire seal of claim 1, wherein the wire seal is a conical wire seal.
8. The wire seal of claim 1, wherein the first core is a first core wire and the second core is a second core wire.
9. A gas turbine comprising the wire seal of claim 1.
10. The gas turbine of claim 9, comprising:
- a combustor and a first vane separated by a gap, and wherein the wire seal is arranged to seal the gap.
11. The gas turbine of claim 10, wherein the combustor comprises:
- a picture frame and wherein the gap is between the first vane and the picture frame.
12. The gas turbine of claim 11, comprising:
- a socket in the picture frame, and wherein the wire seal is seated in the socket.
13. A method of manufacturing a wire seal for sealing a gap between two components of a gas turbine, the wire seal having a first core and a second core spaced apart from one another, a wire pack extending around the first core and the second core, and a fastener for securing the wire pack to the first core and the second core, wherein the wire seal is curved, the method comprising:
- placing the wire pack around the plate; and
- fastening the wire pack to the plate with the fastener.
14. The method of claim 13, in which the wire pack is made of wire and is placed around the first core and the second core by winding the wire repeatedly around the first core and the second core.
Type: Application
Filed: Mar 23, 2016
Publication Date: Sep 29, 2016
Applicant: ANSALDO ENERGIA IP UK LIMITED (London)
Inventors: Sarah HEAVEN (Warwickshire), Stacie TIBOS (Warwickshire), Sascha JUSTL (Zurich)
Application Number: 15/078,297