Patent Description:
Flap seals are conventionally provided for sealing gaps, in particular in a flow machine. The sealing of the gaps in a flow machine reduces a leakage within the flow machine and therefore leads to an increased efficiency of the flow machine. Flap seals are conventionally pushed by a spring against the gap for which the spring has to be supported. In order to support the springs, space consuming structures have to be provided.

In example it is known from <CIT>, to seal gaps between a turbine nozzle and adjacent flow boundary parts by a leaf seal assembly comprising besides the leaf seal a coil spring, finger springs or the like for pressing the leaf seal against an appropriate sealing surface. A U-shaped spring design for a similar arrangement is disclosed in <CIT> and <CIT>. Further sealing designs are disclosed <CIT> and <CIT>.

The space consuming structures lead to increased costs and less available space.

Therefore, it is an object of the invention to provide a sealing device for a flow machine and the flow machine with the sealing device, wherein the sealing device requires only a small amount of space.

The inventive sealing device for a flow machine comprises a flap seal, a surface, a first protrusion protruding from the surface, a second protrusion protruding from the surface and a biasing means that is supported on the first protrusion and the second protrusion and is adapted to push the flap seal away from the first protrusion and the second protrusion in a direction transversal to the normal of the surface, wherein the biasing means comprises a foot that protrudes from a first region of the biasing means in a direction towards the surface, wherein the first region is arranged immediately neighboured to the foot, wherein the foot contacts the surface and biases the remaining biasing means in a direction away from the first protrusion and the second protrusion.

By providing the foot that contacts the surface, the remaining biasing means, in particular the first region, is biased in a direction away from the first protrusion and the second protrusion. It is therefore not required to provide a spring at a distance from the surface in which the first region is arranged. The spring would have to be supported by the first protrusion and/or the second protrusion. The first protrusion and/or the second protrusion therefore do not need to be formed so high that they reach the distance of the first region from the surface but can advantageously be formed lower. Thereby, the first protrusion and the second protrusion can be formed such that they only need a small amount of space. This results therein that the sealing device can be made cost efficient.

For biasing the biasing means the foot can be under a mechanical tension. The mechanical tension can increase if the first region is displaced towards the first protrusion and the second protrusion and the mechanical tension can decrease if the first region is displaced away from the first protrusion and the second protrusion.

It is preferred that the biasing means comprises a contacting part that contacts the flap seal and is arranged between the first protrusion and the second protrusion. It is in particular preferred that the contacting part comprises the first region.

The foot preferably has a curved shape, wherein the foot is adapted to become less curved when the contacting part is displaced away from the first protrusion and the second protrusion.

It is preferred that the biasing means comprises a first arm that protrudes from a second region of the biasing means in a direction away from the surface, contacts the flap seal and is arranged at a distance from the contacting part, wherein the second region is arranged immediately neighboured to the first arm. The flap seal is thereby supported by the biasing means on more than one location which increases the sealing performance of the flap seal.

The biasing means preferably comprises a second arm that protrudes from a third region of the biasing means in a direction away from the surface, contacts the flap seal and is arranged at a distance from the contacting part, wherein the third region is arranged immediately neighboured to the second arm and the contacting part is arranged between the first arm and the second arm. By providing the second arm, the sealing performance of the flap seal can be further increased.

It is preferred that the flap seal has a lower end facing towards the surface and an upper end facing away from the surface, wherein the contacting part contacts the flap seal in a middle between the lower end and the upper end. It was surprisingly found that a wear of the flap seal can be minimized if the biasing means contacts the flap seal in the middle. It is particularly preferred that the lower end and the upper end are parallel to each other and in particular parallel to the surface. It is also preferred that the first arm and the second arm contact the flap seal in the middle, whereby wear of the flap seal can be further reduced.

The sealing device is preferably adapted such that the flap seal can tilt around the lower end.

It is preferred that the sealing device comprises a third protrusion that protrudes away from the surface, is arranged on a side of the flap seal and contacts the flap seal, wherein the side of the flap seal faces away from the first protrusion and the second protrusion. The lower end can for example be arranged in a corner that is formed by the surface and the third protrusion. By doing so, it is possible that the flap seal can tilt around the lower end.

The sealing device preferably comprises a first bearing that is adapted to support the biasing means such that the biasing means can tilt with respect to the first protrusion, wherein the sealing device preferably comprises a second bearing that is adapted to support the biasing means such that the biasing means can tilt with respect to the second protrusion. The first bearing and/or the second bearing are preferably arranged at a distance from the surface, wherein the distance is shorter than the distance from the surface to the middle of the flap. An upper end of the first bearing and/or the second bearing is particularly preferred arranged at the distance from the surface, wherein the upper end is facing away from the surface.

The flow machine according to the invention comprises the sealing device. The flow machine can for example be a steam turbine or a gas turbine. The sealing device can for example be arranged in a compressor section and/or a turbine section of the gas turbine.

It is preferred that the surface is formed by a blade root of a blade of the flow machine. The blade can for example be a guiding vane of the compressor section, a rotating blade of the compressor section, a guiding vane of the turbine section or a rotating blade of the turbine section. The blade can for example also be a guiding vane of a steam turbine or a rotating blade of a steam turbine.

In the following, the invention is explained on the basis of a schematic drawing. The Figure shows a perspective view of a vane with the sealing device.

As it can be seen from the Figure, a sealing device <NUM> for a flow machine comprises a flap seal <NUM>, a surface <NUM>, a first protrusion <NUM> protruding from the surface <NUM>, a second protrusion <NUM> protruding from the surface <NUM> and a biasing means <NUM>. The first protrusion <NUM> and the second protrusion <NUM> are arranged at a distance to each other. The biasing means <NUM> is supported on the first protrusion <NUM> and the second protrusion <NUM> and is adapted to push the flap seal <NUM> away from the first protrusion <NUM> and the second protrusion <NUM> in a direction transversal to the normal <NUM> of the surface <NUM>. The biasing means <NUM> comprises a foot <NUM> that protrudes from a first region of the biasing means <NUM> in a direction towards the surface <NUM>, wherein the first region is arranged immediately neighboured to the foot <NUM>, wherein the foot <NUM> contacts the surface <NUM> and biases the remaining biasing means <NUM> in a direction away from the first protrusion <NUM> and the second protrusion <NUM>.

The flap seal <NUM> can have the shape of a plate, wherein the largest surface or one of the largest surfaces of the plate can be in particular rectangular, see the Figure. An angle between the largest surface or one of the largest surfaces of the plate and the normal <NUM> can for example be from <NUM>° to <NUM>°, in particular from <NUM>° to <NUM>°. The flap seal <NUM> can have a lower end <NUM> facing towards the surface <NUM> and an upper end <NUM> facing away from the surface <NUM>. The lower end <NUM> and the upper end <NUM> can be parallel to each other. In addition, the lower end <NUM> and the upper end <NUM> can be parallel to the surface <NUM>.

The Figure shows that the sealing device <NUM> can comprise a third protrusion <NUM> that protrudes in a direction away from the surface <NUM>, is arranged on a side of the flap seal <NUM> and contacts the flap seal <NUM>, wherein the side of the flap seal <NUM> faces away from the first protrusion <NUM> and the second protrusion <NUM>. The biasing means <NUM> is thereby adapted to push the flap seal <NUM> against the third protrusion <NUM>. The third protrusion <NUM> can protrude from the surface <NUM>, as shown in the Figure, or can protrude from a part of the sealing device <NUM>, wherein the part is different from the surface <NUM>.

The sealing device <NUM> can comprise a first bearing <NUM> that is adapted to support the biasing means <NUM> such that the biasing means <NUM> can tilt with respect to the first protrusion <NUM>. The sealing device <NUM> can furthermore comprise a second bearing <NUM> that is adapted to support the biasing means <NUM> such that the biasing means <NUM> can tilt with respect to the second protrusion <NUM>. In the case that the biasing means <NUM> pushes the flap seal <NUM> against the third protrusion <NUM> and the lower end <NUM> is arranged in a corner formed by the third protrusion <NUM> and the surface <NUM>, the sealing device <NUM> is adapted such that the flap seal <NUM> can tilt around the lower end <NUM>.

The first bearing <NUM> can be formed by a first bearing part <NUM> of the biasing means <NUM> and a first rod <NUM> that extends through a through hole in the first protrusion <NUM> and a through hole in the first bearing part <NUM>. A clearance between the first rod <NUM> and an edge of the through hole in the first bearing part <NUM> can be dimensioned such that the biasing means <NUM> can tilt with respect to the first protrusion <NUM>. The first rod <NUM> can be fixedly attached to the first protrusion <NUM>. Furthermore, the first rod <NUM> can comprise a head (not shown) having a larger diameter than a part of the first rod <NUM>, wherein the part of the first rod <NUM> is arranged immediately neighboured to the head, so that the first bearing part <NUM> is confined between the head of the first rod <NUM> and the first protrusion <NUM>. Analogously, the second bearing <NUM> can be formed by a second bearing part <NUM> of the biasing means <NUM> and a second rod <NUM> that extends through a through hole in the second protrusion <NUM> and a through hole in the second bearing part <NUM>. A clearance between the second rod <NUM> and an edge of the through hole in the second bearing part <NUM> can be dimensioned such that the biasing means <NUM> can tilt with respect to the second protrusion <NUM>. The second rod <NUM> can be fixedly attached to the second protrusion <NUM>. Furthermore, the second rod <NUM> can comprise a head (not shown) having a larger diameter than a part of the second rod <NUM>, wherein the part of the second rod <NUM> is arranged immediately neighboured to the head, so that the second bearing part <NUM> is confined between the head of the second rod <NUM> and the second protrusion <NUM>.

Figure <NUM> shows that the biasing means <NUM> can comprise a contacting part <NUM> that contacts the flap seal <NUM> and is arranged between the first protrusion <NUM> and the second protrusion <NUM>. The contacting part <NUM> can comprise the first region. The contacting part <NUM> can for example contact the largest or one of the largest surfaces of the flap seal <NUM>. The biasing means <NUM> can comprise a first connecting arm <NUM> that is attached on a first end of the contacting part <NUM> and a second connecting arm <NUM> that is attached on a second end of the contacting part <NUM>, wherein the second end is facing away from the first end. The first connecting arm <NUM> connects the contacting part <NUM> to the first bearing part <NUM> and the second connecting arm <NUM> connects the contacting part <NUM> to the second bearing part <NUM>. A respective angle can be formed by the first bearing part <NUM> and the first connecting arm <NUM>, by the first connecting arm <NUM> and the contacting part <NUM>, by the contacting part <NUM> and the second connecting arm <NUM> and by the second connecting arm <NUM> and the second bearing part <NUM>.

The foot <NUM> can have a curved shape, see the Figure, wherein the foot <NUM> is adapted to become less curved when the contacting part <NUM> is displaced away from the first protrusion <NUM> and the second protrusion <NUM>. The foot <NUM> can be under a mechanical tension that becomes weaker when the contacting part <NUM> is displaced away from the first protrusion <NUM> and the second protrusion <NUM>.

As it can be seen from the Figure, the biasing means <NUM> can comprise a first arm <NUM> that protrudes from a second region of the biasing means <NUM> in a direction away from the surface <NUM>, contacts the flap seal <NUM> and is arranged at a distance from the contacting part <NUM>, wherein the second region is arranged immediately neighboured to the first arm <NUM>. The second region can comprise the first bearing part <NUM>. The biasing means <NUM> can comprise a second arm <NUM> that protrudes from a third region of the biasing means <NUM> in a direction away from the surface <NUM>, contacts the flap seal <NUM> and is arranged at a distance from the contacting part <NUM>, wherein the third region is arranged immediately neighboured to the second arm <NUM> and the contacting part <NUM> is arranged in a direction from the first protrusion <NUM> to the second protrusion <NUM> between the first arm <NUM> and the second arm <NUM>. The third region can comprise the second bearing part <NUM>.

The contacting part <NUM>, the first arm <NUM> and/or the second arm <NUM> can contact the flap seal <NUM> in a middle between the lower end <NUM> and the upper end <NUM>, see the Figure. The first rod <NUM>, in particular the complete first rod <NUM>, can be arranged in the direction of the normal <NUM> between the middle and the surface <NUM>. The second rod <NUM>, in particular the complete second rod <NUM>, can be arranged in the direction of the normal <NUM> between the middle and the surface <NUM>.

The Figure shows that the sealing part <NUM> can be part of a flow machine. The middle of the flap seal <NUM>, wherein the middle is contacted by the contacting part <NUM>, can be arranged in a middle between the lower end <NUM> and the upper end <NUM> in a radial direction of the flow machine.

Claim 1:
Sealing device for a flow machine, wherein the sealing device (<NUM>) comprises a flap seal (<NUM>), a surface (<NUM>), a first protrusion (<NUM>) protruding from the surface (<NUM>), a second protrusion (<NUM>) protruding from the surface (<NUM>) and a biasing means (<NUM>) that is supported on the first protrusion (<NUM>) and the second protrusion (<NUM>) and is adapted to push the flap seal (<NUM>) away from the first protrusion (<NUM>) and the second protrusion (<NUM>) in a direction transversal to the normal (<NUM>) of the surface (<NUM>), characterized in that the biasing means (<NUM>) comprises a foot (<NUM>) that protrudes from a first region of the biasing means (<NUM>) in a direction towards the surface (<NUM>), wherein the first region is arranged immediately neighboured to the foot (<NUM>), wherein the foot (<NUM>) contacts the surface (<NUM>) and biases the remaining biasing means (<NUM>) in a direction away from the first protrusion (<NUM>) and the second protrusion (<NUM>).