GB1580884A - Sealing means - Google Patents

Description

(54) SEALING MEANS (71) We, ROLLS-ROYCE LIMITED, a British Company of 65 Buckingham Gate, London, SWi E 6AT, formerly of Norfolk House, St James's Square, London SW17 4JR do hereby declare the invention, for which we pray that a patent may be granted to us, and th method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to sealing means for sealing between two static members.

It has previously been proposed that in order to provide a seal between two static members, facing surfaces should be cut-away to provide facing grooves, and in these facing grooves a sealing member should be located. Such a structure is claimed in our prior patent 1,081,458, and it will be seen from this patent that the sealing member is described as being in in the form of a flat strip or a circular crosssection wire. Such a structure has been widely used and is very successful. However, when assembling the two static members together, because of manufacturing tolerances, etc. the facing grooves do not always line up exactly and it has been the practice in the past to make the sealing strip of considerably smaller dimensions than the grooves which receive it, this compensates to some degree for misalignment of the grooves but also allows some leakage between the members.

The present invention provides a sealing arrangement in which misalignments are allowed without so much degradation of sealing efficiency.

According to the present invention, sealing means for sealing between two members comprises facing grooves formed in abutting faces of the members and a sealing strip located in the facing grooves, the sealing strip comprising in scross-section bulbous edge portions of similar transvere dimension to that of the facing grooves, these edge portions being joined by a thinner central portion, each bulbous edge portion engaging in one said groove and the strip being allowed to lie at an angle to accommodate misalignment between the grooves.

In a preferred embodiment the bulbous portions are of substantially part-circular cross-section.

The invention is particularly applicable to the seals between structures such as nozzle guide vanes in gas turbine engines.

The invention will now be particularly described merely by way of example, with reference to the accompanying drawings in which: Figure 1 is a partly broken away side elevation of a gas turbine engine incorporating sealing means in accordance with the invention, Figure 2 is an enlarged section through part of the turbine of Figure 1 and Figure 3 is a further enlarged view of part of Figure 2.

In Figure 1 there is shown a gas turbine engine 10 comprising a compressor section 11, combustion section 12, turbine 13 and propelling nozzle 14. Operation of the engine is conventional and will not be described in detail. The casing of the engine is shown broken away in the region of the combustion section 12 and turbine 13 and visible through this broken away portion are the nozzle guide vanes 15 which serve to direct gases from the combustion section onto the turbine.

In a conventional manner the nozzle guide vanes 15 comprise an annular array of aerofoil sections 16 and inner and outer platforms 17 and 18 respectively. The platforms 17 abut together to form an annular interior wall of the gas passage and in a similar manner the outer platforms 18 abut to form the outer wall. In order to prevent gas leaking from the hot gas passage into other parts of the engine or excess cooling air leaking into the hot gas passage, it is necessary to provide sealing means between the abutting faces of the platforms 17 and 18.

In the present invention each of the abutting faces is provided with an axially extending groove, the grooves in the abutting surfaces facing one another. Thus in the enlarged section of Figure 3 abutting surfaces 19 and 20 are illustrated, and in the surface 19 a groove 21 is formed which faces the groove 22 formed in the face 20. Within the rectangular channel formed by the grooves 21 and 22, there is mounted an axially extending sealing strip 23.

The strip 23 consists of two bulbous edge portions 24 and 25 interconnected by a narrow central portion 26. The bulbous edge portions 24,25 are arranged to be of substantially the same thickness as the width of the grooves 21,22 respectively. In fact in the embodiment shown the edge portions are substantially circular in cross-section and are of the same diameter.

It will be seen that the sealing strip 23 thus forms a close fitting seal within the grooves 21 and 22, and by virtue of the narrow central portion a certain amount of misalignment of the two platforms 18 may be tolerated. This is illustrated by the section shown in broken lines in Figure 3 where it will be seen that with the groove 21 displaced by almost its own width with respect to the groove 22, the sealing strip 23 still fits closely in the grooves and accommodates the misalignment by taking up an angled position.

It will be understood that similar sealing arrangements are likely to be used on the inner platforms 17 as well as the outer platforms, and that a similar sealing arrangement could be used in a variety of different applications. It will also be noted that the sealing device of the invention will work with different sections for the sealing strip, the only requirement being that it has bulbous edges joined by a narrow central section. Again although in the embodiment described it will be necessary for the strip to be metal, in other applications other materials such as thermoplastic or ceramic could be used.

WHAT WE CLAIM IS: 1. Sealing means for sealing between two members comprising facing grooves formed in abutting faces of the members and a sealing strip located in the facing grooves, the sealing strip comprising in cross-section bulbous edge portions of similar transverse dimension to that of the facing grooves, these bulbous edge portions being joined by a thinner central portion, each bulbous edge portion engaging in one saud groove and the strip being allowed to lie at an angle to accommodate misalignment between the grooves.

2. Sealing means as claimed in Claim 1 and in which bulbous portions are of substantially part-circular cross-section.

3. Sealing means as claimed in Claim 2 and in which the bulbous portions are of the same diameter in cross-section.

4. Sealing means as claimed in any preceding claim and in which said members comprise static parts of a gas turbine engine.

5. Sealing means as claimed in Claim 4 and in which said static parts of a gas turbine engine comprise the abutting platforms of adjacent ones of an annular array of nozzle guide vanes.

6. Sealing means substantially as hereinbefore particularly described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. portions 24,25 are arranged to be of substantially the same thickness as the width of the grooves 21,22 respectively. In fact in the embodiment shown the edge portions are substantially circular in cross-section and are of the same diameter. It will be seen that the sealing strip 23 thus forms a close fitting seal within the grooves 21 and 22, and by virtue of the narrow central portion a certain amount of misalignment of the two platforms 18 may be tolerated. This is illustrated by the section shown in broken lines in Figure 3 where it will be seen that with the groove 21 displaced by almost its own width with respect to the groove 22, the sealing strip 23 still fits closely in the grooves and accommodates the misalignment by taking up an angled position. It will be understood that similar sealing arrangements are likely to be used on the inner platforms 17 as well as the outer platforms, and that a similar sealing arrangement could be used in a variety of different applications. It will also be noted that the sealing device of the invention will work with different sections for the sealing strip, the only requirement being that it has bulbous edges joined by a narrow central section. Again although in the embodiment described it will be necessary for the strip to be metal, in other applications other materials such as thermoplastic or ceramic could be used. WHAT WE CLAIM IS:

1. Sealing means for sealing between two members comprising facing grooves formed in abutting faces of the members and a sealing strip located in the facing grooves, the sealing strip comprising in cross-section bulbous edge portions of similar transverse dimension to that of the facing grooves, these bulbous edge portions being joined by a thinner central portion, each bulbous edge portion engaging in one saud groove and the strip being allowed to lie at an angle to accommodate misalignment between the grooves.

2. Sealing means as claimed in Claim 1 and in which bulbous portions are of substantially part-circular cross-section.

3. Sealing means as claimed in Claim 2 and in which the bulbous portions are of the same diameter in cross-section.

4. Sealing means as claimed in any preceding claim and in which said members comprise static parts of a gas turbine engine.

5. Sealing means as claimed in Claim 4 and in which said static parts of a gas turbine engine comprise the abutting platforms of adjacent ones of an annular array of nozzle guide vanes.

6. Sealing means substantially as hereinbefore particularly described with reference to the accompanying drawings.