TURBOMACHINERY WITH CENTRED CASINGS

Abstract

Turbomachinery comprising a turbine housing (200) with an engagement formation (210) and a casing (400) for electrical machinery, the casing (400) including an engagement recess (410). Furthermore, the engagement recess (410) comprises a cantilever member (420) and is adapted to receive the engagement formation (210). Finally, the engagement recess (410) and engagement portion (210) are configured such that during operation of said turbomachinery the engagement formation undergoes thermal expansion to expand relative to the engagement recess and exert pressure on the cantilever (member 420). In this way, an improved apparatus for centralising the turbine housing (200) in relation to the casing (400) is provided.

Claims

1. Turbomachinery comprising, a turbine housing comprising an engagement formation, and a casing for electrical machinery comprising an engagement recess, wherein said engagement recess comprises a cantilever member, said engagement recess adapted to receive said engagement formation, and wherein said engagement formation and said engagement recess are configured such that during operation of said turbomachinery said engagement formation undergoes thermal expansion to expand relative to said engagement recess and exert pressure on said cantilever member.

2. The turbomachinery of claim 1, wherein said turbomachinery apparatus further comprises a turbine located within said turbine housing and extending from said casing.

3. The turbomachinery of claim 1, wherein there is a gap or space between the engagement formation and the length of the cantilever member at ambient temperature.

4. The turbomachinery of claim 1, wherein said cantilever member comprises an annular cross section.

5. The turbomachinery of claim 1, wherein a side of said engagement recess comprises said cantilever member.

6. The turbomachinery of claim 1, wherein the thermal expansion coefficient of said turbine housing differs from the thermal expansion coefficient of said casing.

7. The turbomachinery of claim 6, wherein the thermal expansion coefficient of said turbine housing is within 30% of the thermal expansion coefficient of said casing.

8. The turbomachinery of claim 1, wherein the engagement formation comprises a taper or chamfer.

9. The turbomachinery of claim 1, where the length of the cantilever member is extended by a undercut within the engagement recess.

10. The turbomachinery of claim 9, wherein the undercut comprises a rounded profile.

11. The turbomachinery of claim 1, wherein a surface of said engagement formation comprises a textured area.

12. The turbomachinery of claim 11, wherein an entire surface of the engagement formation is textured.

13. The turbomachinery of claim 1, wherein a surface of said engagement recess comprises a textured area.

14. The turbomachinery of claim 13, wherein an entire surface of the engagement recess is textured.

15. The turbomachinery of claim 1, wherein the turbomachinery further comprises a gasket between said turbine housing and said casing.

16. The turbomachinery of claim 15, wherein the thermal conductivity of said gasket is lower than the thermal conductivity of both said turbine housing and said casing.

17. The turbomachinery of claim 1, wherein said cantilever member comprises a groove positioned facing a surface of said engagement formation.

18. The turbomachinery of claim 1, wherein said turbomachinery further comprises a stud connecting said turbine housing to said casing.

19. The turbomachinery of claim 18, wherein said stud extends through said casing to engage with said turbine housing.

20. The turbomachinery of claim 18, wherein said stud comprises a screw thread.

21. The turbomachinery of claim 1, wherein said turbine housing comprises a plurality of engagement formations, and said casing comprises a plurality of engagement recesses.

22. The turbomachinery of claim 1, wherein said turbomachinery is a turbogenerator.

23. A turbine housing for use in the turbomachinery of claim 1.

24. A casing for electrical machinery for use in the turbomachinery of claim 1.

Description

DETAILED DESCRIPTION

[0028] Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:

[0029] FIG. 1 is a schematic cross-sectional view of turbomachinery in accordance with the present invention; and

[0030] FIG. 2 is an expanded, schematic cross-sectional view of the area highlighted in FIG. 1.

[0031] Referring to FIG. 1 of the drawings, there is shown a piece of turbomachinery 100 in accordance with the present invention. Here, the piece of turbomachinery comprises a turbine housing 200, a turbine 300, and a casing 400. The casing 400 contains a portion of the turbine 300 and further electrical components 500 required for operation of the turbomachinery. As is typical for turbomachinery, the tips of the turbine blades 301 are located in close proximity to an interior surface of the turbine housing 200 to ensure efficient operation.

[0032] To ensure the tips of the turbine blades 301 are held in close proximity to the turbine housing 200, the turbine housing 200 is affixed to the casing 400 by multiple fastening arrangements 1000. These fastening arrangements 1000 are positioned around the periphery of the turbine housing 200 and the casing 400, where the turbine housing 200 and the casing 400 abut. The fastening arrangements 1000 may be spaced equally around the periphery or perimeter of the turbine housing 200 and the casing 400. Alternatively, a single fastening arrangement 1000 may extend around the entire perimeter of the turbine housing 200 and the casing 400.

[0033] The fastening arrangement 1000 is depicted in greater detail in FIG. 2. Again, the turbine housing 200 and the casing 400 are illustrated, alongside further features of this embodiment of the invention.

[0034] An engagement formation, protrusion or spigot 210 is located on the outside of the turbine housing 200. The engagement formation 210 extends from an outer surface of the turbine housing 200. This engagement formation 210 has a generally rectangular cross section. Additionally, the engagement formation 210 comprises a tapered or chamfered portion 211 located at its distal end.

[0035] The casing 400 includes and engagement recess, hole or blind aperture 410. This engagement recess 410 is formed on two side by the casing 400, and is formed on a third side by a cantilever member or locating projection 420. The cantilever member 420 extends from a surface of the the housing 400 to form a third side of the engagement recess 410. The cantilever member 430 is curved around an axis parallel to its length. Additionally, the cantilever member 430 may have an annular cross section.

[0036] The engagement recess 410 is sized to house, fit or accommodate the engagement formation 210. The engagement formation 210 fits relatively loosely within the engagement recess 410, such that insertion of the engagement formation 210 into the engagement recess 410 may be easily undertaken by the user during assembly of the turbomachinery 100.

[0037] The length of the cantilever member 420 is extended by a cutaway or undercut 430 located within the engagement recess 410. The undercut 430 extends in a direction generally parallel to the direction of the cantilever member 420. The undercut 430 has a curved, rounded or circular cross section, such that the issues of stress concentration are mitigated.

[0038] The cantilever member 420 includes a groove or channel 421. This groove 421 is located on a lower surface of the cantilever member 420, adjacent to the engagement formation 210. Additionally, areas of the surface of any or all of the cantilever member 420, groove 421, engagement recess 410 or engagement formation 210 may have a textured or roughened surface texture.

[0039] A barrier material or gasket 440 is located between the engagement formation 210 and the casing 400 in the engagement recess 410. The gasket 440 is formed of a material with a low thermal conductivity such as a chemically and thermally exfoliated vermiculite and/or steatite material. In this embodiment, the gasket 440 is formed of a material with a lower thermal conductivity than both the turbine housing 200 and the casing 400.

[0040] The fastening arrangement includes a stud, fastener, or bar 450 which extends through the casing 400 into the turbine housing 200. This stud 450 assists the location of the turbine housing 200 in relation to the casing 400, providing an axial clamping force. The stud includes a screw thread, on to which a nut 451 is tightened by a user during the assembly of the turbomachinery 100. To ensure the nut 451 does not excessively restrict the radial movement of the turbine housing 200 in relation to the casing 400, a spherical washer is used between the nut 451 and the casing 400. To further ensure the turbine housing 200 is free to move radially relative to the casing 400, the casing aperture through which the stud 450 is inserted is slightly larger than the stud itself. In this embodiment, the aperture has a diameter 108% that of the stud 450.

[0041] Due to the different temperatures experienced by the turbine housing 200 and the and the casing 400 during operation of the turbomachinery 100, the engagement formation 210 effectively expands within the engagement recess 410. Initially, due to the relatively loose fit of the engagement formation 210 within the engagement recess 410, the engagement formation 210 is not in contact with the cantilever member 420. However, as the engagement formation 210 thermally expands, it comes into contact with the cantilever member 420. The cantilever member 420 then exerts a spring force on to the engagement formation 210, assisting in the centralisation of the turbine housing 200 relative to the casing 400. The force of the cantilever member 420 on the engagement formation 210 is increased by the undercut 430, which effectively increases the length of the cantilever member 420. Such a system ensures that the turbine housing 200 is centralised relative to the casing 400 throughout the warm-up and cool down phases of operation, as well as in the steady state phase.