GB2182399A

GB2182399A - Sealing means between two members

Info

Publication number: GB2182399A
Application number: GB08526787A
Authority: GB
Inventors: Michael Colin Roberts
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 1985-10-30
Filing date: 1985-10-30
Publication date: 1987-05-13
Also published as: DE3635986A1; JPS62142807A; FR2589546A1

Abstract

An apparatus, for sealing between two members eg adjacent vanes in a gas turbine engine, comprising a strip of metal of arcuate cross-sectional form which is inserted into a recess formed in each confronting face of the members. The sealing member is positioned such that the gas pressure experienced by said sealing member acts to increase the sealing effect of said seal. <IMAGE>

Description

SPECIFICATION Improvements in or relating to sealing means between two or more members This invention relates to sealing means between two or more members and is particularly applicable to sealing means between adjacent vanes of a gas turbine engine.

In a gas turbine engine, it is normally necessary to provide sealing means between the parts of adjacent vanes which form part of the flow annulus, i.e. between the root platforms and/or between the outer platforms.

A well known sealing means comprises a flat strip of metal which is positioned along the interplatform gap and extends into a recess in each of the platforms as shown in figure A.

In operation, the higher gas pressure acting on the strip forces it against the wall of each recess continuously along its length to provide an air-tight seal.

It has been found, however, that due to poor manufacturing and assembly tolerances, each slot may be positioned at a skew angle relative to the adjacent siot such that the recesses are not parallel along their lengths.

When such a condition arises it is impossible to seal the inter-platform gap with a flat strip.

The net gas pressure acting on the strip tends to tilt the strip and lift one edge out of contact with its associated recess, this allows air to escape past the seal.

It is an object of the present invention to provide a sealing means which reduces, and possibly eliminates the above mentioned problem.

According to the present invention, there is provided a sealing member for a gas turbine engine of the type that has a plurality of angularly spaced apart segments, which have one or more vanes and in which each of said segments is provided with one or more end portions provided with at least one recess having two sides, which co-operates with a corresponding recess in an adjacent vane end portion to form a void in which the sealing member is inserted, the sealing member comprising a strip of metal of arcuate cross-sectioned form having a convex side, a concaved side and two edges.

Preferably, the sealing member has a height-measured as the perpendicular distance between the plane containing both edges of the member and a point farthest away from said plane on the convex side of said mem ber-which is greater than the perpendicular distance between the two side faces of any recess, such that the member is an interfer ence push fit into said void.

The invention will now be more particularly described by way of example only with refer ence to the accompanying drawings, in which: Figure A illustrates the prior art.

Figure 1 is a diagrammatic view of a gas turbine turbine engine showing an embodiment of the present invention.

Figure 2 is an enlarged pictorial view of part of the embodiment shown in Fig. 1.

Figure 3 is a view in the direction of arrow A in Fig. 2.

Figure 4 is a view in the direction of arrow B in Fig. 2.

Figure 5 is a cross-sectional view in the direction of arrows C-C in Fig. 4.

Figure 6 is a cross-sectional view in the direction of arrows D-D in Fig. 3.

Figure 7 is a cross-sectional view in the direction of arrows D-D in Fig. 3, illustrating the segments in their misplaced position.

Referring to Fig. 1 a gas turbine engine shown generally at 10 comprises an intake 12, compressor section 13, combustion section 14 and turbine section 15 terminating in an exhaust nozzle 16. A broken-away portion of the casing around the turbine Section 15 shows diagrammatically the turbine vanes incorporating the present invention.

Fig. 2 is an enlarged pictorial view of the broken away portion shown in Fig. 1 and illustrates two vanes (17) and (18), each of which comprises an aerofoii shaped section (19), a outer platform (20) and an inner platform (21).

The outer platform (20) and the inner platform (21) of the two vanes (17,18) are integrally joined to each other to form a segment (22).

The end faces (23) and (24) of the inner platform (21) and/or outer platform (20) are provided with an axially extending recess (25), which forms part of the sealing means. Each recess (25) co-operates with a second recess (25) formed in the end faces (23,24) of the next adjacent segment (22) (shown dotted in Figs. 5 or 6) to provide a void (26) in which a sealing member (27) is positioned. The sealing member (27), best seen in Fig. 7, comprises a strip of metal which is arcuate in crossection and has a convex side (30), a concaved side (31) and two edges (X,Y).

Referring now to the drawings in general but particularly Figs. 5 to 7, it will be seen that the sealing member (27) is positioned along the interplatform-gap (28) and extends into the recess (25) in each end face (23,24) such that the edges (X,Y) and the convex side (30) act against the side walls of the recess (29).

Referring now particularly to Fig. 7, the sealing member (27) has a height H which is slightly larger than the perpendicular distance h between the two side walls (29) of each recess (25). Upon assembly a small interfer ence (H-h) causes the sealing member (27) to deform continuously along its length such that each edge (X,Y) of the sealing member (27) is aligned with, and seals against, the walls (29) of the recess (25) and the convex side (30) seals against one or both of the opposite walls (29).

In operation, the sealing member (27) is positioned such that its convex side (30) experiences the greatest pressure, which causes the contact load of said edges (X,Y) against the walls (29) to be further increased, thus providing a more efficient seal.

It will be appreciated that an efficient seal may still be produced without the aid of the interference fit (H-h). In the case where Hth, because of for example assembly problems, it has been found that the pressure P acting on said sealing member (27) is sufficient to maintain a good seal along each edge (X,Y) throughout the centre length of the sealing member (27).

It will also be appreciated that whilst the walls (29) of the recess are shown parallel to each other throughout the drawings they need not be so, and in fact may taper inwardly towards the base of the recess (25) to assist the fitting of the seals (27).

It will also be appreciated that whilst the invention has been described for use between parts of adjacent vanes in a gas turbine engine it may be used between adjacent parts of any components requiring an efficient seal.

One example of such a component would be a rotor for a gas turbine engine. In such an application, consideration should be given to the centrifugal force which would act on the seal (27) during engine operation. Preferably, the seal (27) should be positioned such that the convex side (30) experiences the load created centrifugal force such that the sealing efficiency is still further increased.

Claims

1. A sealing member for a gas turbine engine of the type that has a piurality of angularly spaced apart segments which have one or more vanes and in which each of said segments is provided with one or more end portions provided with at least one recess having two side walls, said recess co-operating with a corresponding recess in an adjacent vane end portion to form a void in which the sealing member is inserted, the sealing member comprising a strip of arcuate cross-sectioned form having a convex side, a concave side and two edges.

2. A sealing member according to claim 1 in which the member has a height, measured as the perpendicular distance between a plane containing both edges of the member and a point furthest from said plane on the convex side of said member, which is greater than the perpendicular distance between the two sides of each of the recesses defining the void in which the sealing member is inserted.

3. A sealing member for a gas turbine engine according to claim 1 in which the one or more end portions are formed by the inner platform portion of a vane.

4. A sealing member for a gas turbine engine according to claim 1 in which the one or more end portions are formed by the outer plafform-portion of a vane.

5. A gas turbine engie having a sealing member substantially as herein described.-with reference to Figs. 1 to 7 of the accompanying drawings.