CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of European Application No. EP20165112 filed 24 Mar. 2020, incorporated by reference herein in its entirety.

FIELD OF INVENTION

The invention relates to a two-piece or multiple-piece sealing washer for use in a rotor, in particular in a gas turbine, the ends of the sealing washer overlapping, in order in this way to reduce leakage through the gap which is formed. It is provided here that the sealing washer brings about sealing with respect to further rotor components by means of the centrifugal force. In the case of the present type here, the cross section of the sealing washer is very small in comparison with its diameter.

BACKGROUND OF INVENTION

The prior art has disclosed a sealing washer which has two sealing faces which are arranged at an angle with respect to one another and, in the case of rotation of the rotor, bring about sealing of a gap by means of the centrifugal force. Here, one of the two sealing faces bears against a rotor component on one side of the gap and the other sealing face bears against another rotor component on the other side of the gap.

On account of the multiple-piece configuration of the sealing washer, the ends of the individual sealing washer segments overlap, with the result that no new gap remains open between the sealing washer segments. On account of the relatively small cross section, there is fundamentally a split in half of the sealing washer at a median radius in the case of the overlapping sections, with the result that the two sections which lie above one another have a sufficient rigidity.

It is disadvantageous in the case of the known embodiment, however, that a gap, which, even if it is very small, is not sealed completely, remains in the case of the overlap. In particular, the known embodiment leads to one of the two sections comprising one of the two sealing faces only intermittently, but not exhibiting any sealing on the other sealing face.

SUMMARY OF INVENTION

It is therefore an object of the present invention to further improve the sealing by means of a sealing washer.

The object which is addressed is achieved by way of an embodiment according to the invention in accordance with the teaching of the independent claim. A rotor according to the invention with a corresponding sealing washer is specified in a further independent claim. Advantageous embodiments are the subject matter of the subclaims.

The sealing washer of the generic type serves firstly for use in a rotor for sealing a circumferential gap between various rotor components. The type of rotor here is initially irrelevant, the use being possible, in particular, in the case of a gas turbine. Here, the sealing washer or the rotor defines a rotor axis.

Here, the sealing washer has a bearing face which extends approximately radially and in the circumferential direction. This is considered to be the case if the angle between the bearing face and a radial direction is at most 15°. Here, the bearing face is delimited by way of an inner bearing edge on the side which points toward the rotor axis and by an outer bearing edge on the side which points radially to the outside.

Furthermore, the sealing washer has a supporting face which is oriented in an inclined manner with respect to the rotor axis. It is provided here that an angle between the supporting face and the rotor axis is at least 15°, but at most 45°. Here, as viewed in the direction of the rotor axis, the supporting face is delimited by a front supporting edge on one side and by a rear supporting edge on an opposite side. Here, the front supporting edge is situated on the side which points toward the bearing face, whereas, in contrast, the rear supporting edge is situated on the sealing washer on the side which points away from the bearing face.

In the circumferential direction, the sealing washer comprises at least one washer section with a substantially constant cross section. Furthermore, the sealing washer has a pressing section and a triangular section. Here, the pressing section adjoins a first section end of the washer section in one piece in the circumferential direction. In contrast, the triangular section is connected in one piece to a washer section at a second section end, it being possible for this to be the same washer section as before or another washer section. A dividing point is therefore produced. It is provided here that the pressing section overlaps the triangular section in the circumferential direction at the at least one dividing point and therefore forms an overlapping region.

Here, a gap remains between the free end of the pressing section and the second section end and, furthermore, between the free end of the triangular section and the first section end. The gaps are required here, in order to permit tolerance compensation and different thermal expansions of the rotor components and the sealing washer. Here, the gaps can be provided structurally with identical dimensions.

Here, the division between the triangular section and the pressing section forms a dividing face. Here, as viewed in the axial direction, the dividing face is delimited firstly by way of a lower dividing face edge and, opposite this, by an upper dividing face edge. Here, the lower dividing face edge is situated generically between the center of the bearing face and the inner bearing edge of the bearing face. Accordingly, both the triangular section and the pressing section have the bearing face in sections. The seal is ensured substantially at this point as long as it is ensured that both the triangular section and the pressing section bear reliably against the adjacent rotor component with the bearing face.

On account of the orientation of the supporting face in an approximation of a cylindrical face, it is ruled out, by way of the customary division in half between the two overlapping sections in the prior art with a separating face which is provided substantially as a section of a cylindrical face, that the section which points toward the rotor axis has a part of the supporting face.

In contrast, it is provided according to the invention that the dividing face is then oriented in an opposed manner with respect to the supporting face, and an unequal distribution between the triangular section and the supporting section is accepted here. It is provided here that the cross-sectional area of the triangular section corresponds merely to up to 0.3 times the cross-sectional area of the washer section. As a consequence, the cross section of the pressing section is at least twice the cross-sectional area of the triangular section. This leads to the possibility of arranging the upper dividing face edge in a region between the center of the supporting face and the rear supporting edge.

The embodiment according to the invention makes it possible for the triangular section and the pressing section as overlapping sections of the sealing washer to likewise be provided at least to some extent with a section of the supporting face, with the result that sealing can be substantially ensured even in this region. In this way, leakage in the region of the overlap can be reduced further in comparison with the embodiment in the prior art.

Sealing by means of the sealing washer is advantageously ensured if the corresponding sealing faces have a sufficient width. (It is generally the case that it is advantageous if the sealing face is configured to be as wide as possible.) To this end, it is advantageous if the bearing face has a bearing height from the lower bearing edge as far as the upper bearing edge, measured in the radial direction, of at least 0.5 times the height of the sealing washer, likewise measured as a dimension in the radial direction. It is likewise advantageous if the supporting face has a supporting width from the rear supporting edge as far as the front supporting edge, measured in the axial direction, of at least 0.5 times the width of the sealing washer, likewise measured in the axial direction.

In order to ensure an advantageous cross section of the triangular section, it is advantageous if the lower dividing face edge is arranged in the vicinity of the inner bearing edge, the spacing from the center of the bearing face being greater than the spacing from the inner bearing edge. In an analogous manner, it is advantageous if the upper dividing face edge is arranged in the vicinity of the rear supporting edge. To this end, the spacing of the upper dividing face edge from the rear supporting edge is to be selected to be smaller than the spacing of the upper dividing face edge from the center of the supporting face.

Furthermore, it is advantageous for the division according to the invention between the triangular section and the pressing section if the dividing face is oriented in an inclined manner which is opposed with respect to the supporting face. To this end, it is advantageous if an angle between the dividing face and the radial direction is between 35° and 55°. It follows obviously from this that the advantageous angle between the dividing face and the rotor axis is likewise between 35° and 55°. It is particularly advantageous, however, if the angle between the dividing face and the radial direction as well as between the dividing face and the rotor axis is between 40° and 50°, and to this extent is arranged diagonally, in an inclined manner which is opposed with respect to the supporting face.

Although it would be possible to use a single-piece sealing washer with only one dividing point, the sealing washer is advantageously formed, however, from at least two washer segments. Here, each of the washer segments has a washer section, the two ends of which, which are opposed in the circumferential direction, are adjoined either by a pressing section or a triangular section. As a consequence, there are two dividing points in the case of two washer segments.

Regardless of the presence of two or more washer segments, it is advantageous, furthermore, if there is a closing washer segment. It is provided here that there is a triangular section on both sides on the closing washer segment. This simplifies final assembly of the closing washer segment in order to form the sealing washer.

In a further embodiment, a closing washer segment is advantageously used which extends over a circumference of at most 20°. This embodiment has the special advantage that merely a small piece of the sealing washer in the form of the closing washer segment is to be removed in order to realize a clearance, for example in order to mount a rotor blade. It is initially irrelevant here whether this is combined with the arrangement of the triangular sections at its ends which lie opposite one another.

The production and mounting of the washer segments are simplified if at least two washer segments, particularly advantageously all of the present washer segments, are formed by identical parts.

Generally speaking, it is to be assumed that the gap to be sealed between the adjacent rotor components is small in comparison with the width of the sealing washer. Accordingly, for sealing purposes, the spacing of the supporting face and therefore the outer bearing edge from the bearing face and therefore from the outer bearing edge is advantageously selected to be not greater than 0.2 times the sealing washer width, as measured in the axial direction. In this way, sealing can take place with optimum closeness to the gap.

In accordance with the proper sealing of a gap and therefore a free spacing between adjacent rotor components, an extent of the supporting face with the front supporting edge as far as the bearing face, that is to say as far as the outer bearing edge, is not required in contrast. To this extent, in order to simplify and avoid a sharp edge, a rounded portion and/or flattened portion can be provided from the outer bearing edge to the front supporting edge.

In order to avoid a sharp-edged groove in a rotor disk for the arrangement of the sealing washer with consideration of an installation space which is as small as possible for the sealing washer and in the process ensuring the necessary stability of the sealing washer, it is advantageous if said sealing washer is rounded in a manner which lies opposite the bearing face. To this extent, as viewed in cross section, the sealing washer has an arcuate section opposite the bearing face adjacently with respect to the supporting face in a manner which points radially inward. This makes an analogous shape in the rotor disk possible and therefore avoids the formation of stress peaks in the circumferential groove which is required to this end (and is continuous in the circumferential direction or is in multiple pieces).

To this end, it is advantageous, furthermore, if a straight section is arranged opposite the supporting face on the side which faces the rotor axis, which straight section connects the arcuate section directly or indirectly to the bearing face or the inner bearing edge.

The realization of a sealing washer according to the invention makes the formation of a novel rotor according to the invention possible. The use of the rotor is initially irrelevant, the solution being suitable, in particular, for use in the case of a gas turbine. Here, the rotor comprises at least one rotor disk, on which a plurality of rotor blades are arranged in a manner which is distributed over the circumference. To this end, the rotor disk has a corresponding number of blade holding grooves which extend through the rotor disk and in which in each case one blade root of the respective rotor blades is arranged. Together with the rotor blades or their blade roots, the rotor disk has an end side, in front of which a plurality of sealing elements are arranged in a manner which is distributed over the circumference. Here, the sealing elements advantageously cover the blade roots and, to this extent, the blade holding grooves.

There is a circumferential gap between the rotor disk with the rotor blades and the sealing elements, which circumferential gap is largely sealed by way of a sealing washer in the case of a generic embodiment of a rotor.

It is then provided according to the invention to use an improved solution of the sealing washer as described above, and therefore to further improve the sealing.

The sealing washer which is used here advantageously has a closing washer segment which makes the mounting and disassembly of rotor blades without complete removal of the entire sealing washer possible. To this extent, the closing washer segment extends over a length which is greater than what corresponds to the width of a blade root. Therefore, in the case of removal of the closing washer segment, the blade root can be installed or removed through the gap which is produced.

Here, the closing washer segment is advantageously not of longer configuration in the circumferential direction than necessary. To this end, the covering angular region of the closing washer segment is selected to be smaller than what corresponds to twice the separation of the blade holding grooves. In the case of 72 blade holding grooves, for example, the closing washer segment extends over at most 10°.

