For a better understanding and to show more clearly how it may be carried into effect, reference will now be made by way of example to the accompanying figures, in which:
Referring now to
The disc wheel 22 comprises a sleeve portion 24 and web portion 26 integrally connected to the sleeve portion 24. The sleeve portion 24 is mounted around a shaft 28. The shaft 28 and the interior of the sleeve portion 24 are in rotational engagement, for instance using intermeshed parts 30. Opposite ends 24a, 24b of the sleeve portion 24 are also in an interfering engagement with corresponding portions 28a, 28b of the shaft 28. This connection, called spigot fit, prevents the disc wheel 22 from moving longitudinally.
In the improved air seal arrangement 20, the sleeve portion 24 is extended adjacent to a static knife edge seal 32. The static knife edge seal 32 is connected to a fixed structure 34. In
In the illustrated embodiment, the air seal arrangement 20 is used to regulate the air flow coming from inside the shaft 28 to a chamber underneath the sleeve portion 24. A hole 42 in the shaft 28 creates an air path with the chamber 40. Air is sent to another chamber 44 in fluid communication with one side of the static knife edge seal 32 by mean of a hole 45. Pressurized air is allowed to flow between the free end 32a of the static knife edge seal 32 and the outer surface of the sleeve portion 24. Air flows radially outwards in a chamber 46 on a side of the disc wheel 22 for cooling purposes. This arrangement 20 provides a better air path from inside the shaft 28 and prevents air from escaping through the spigot fit. A seal 50 is provided within the air chamber 40 prevent air form escaping between the rearmost part of the sleeve portion 24 and the shaft 28. Also, the design of the sleeve portion 24 being longer, the disc wheel 22 has a better dynamic stability and generate less vibrations. In
Overall, the air seal arrangement 20 is improved and simplified. The assembly of the parts is also simplified.
The above description is meant to be exemplary only, and one skilled in the art will recognize that other changes may also be made to the embodiments described without departing from the scope of the invention disclosed as defined by the appended claims. For instance, the present invention is not limited to a turbine disc wheel and can also be used on a compressor disc wheel. It is also not limited to a wheel exactly as illustrated, nor a static knife edge seal exactly as illustrated. For instance, the outer surface of the sleeve portion can be inclined with reference to the central axis of the wheel or even be curved. It can also be shorter than what is shown. Still other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.