US3366365A - Turbines - Google Patents

Description

Jan. 3o, 1966 W. RIZK 3,366,365

TURBINES Filed Sept. 16, 1965 4 Sheets-Sheet 5 Jan. 30, 1968 L w. RlzK 3,366,365'

TURBINES Filed Sept. 16, 1965 v 4 4 Sheets-Sheet 4 United States Patent O 3,366,365 TURBINES Waheeb Rizk, Whetstone, England, assignor to The English Electric Company Limited, London, England, a British company Filed Sept. 16, 1965, Ser. No. 487,696 Claims priority, application Great Britain, Sept. 29, 1964, 39,703/64 4 Claims. (Cl. 253-39) ABSTRACT OF THE DISCLOSURE A turbine has its rotor mounted in bearing-supporting structure, which is mounted on a foundation, and has its main pressure-containing casing, through which gas is supplied to the rotor, supported and positioned independently of the bearing-supporting structure, in a way to allow thermal expansion of the main pressure-containing casing while maintaining it accurately concentric with the rotor, by means including:

(i) a pair of supporting plates pin-jointed to the casing, one on each side, to support the major part of the weight of the casing and to locate it against vertical movement and against turning about the rotational axis of the turbine,

(ii) at least one rod, which locates the casing against rotation about a transverse horizontal axis, and

(iii) rst key-andkeyway means which locate the casing against movement parallel to the turbine rotational axis and against turning about a vertical axis, and second key-and-keyway means which centralizes the casing and locates it against transverse movement.

SPECIFICATION This invention relates to turbines.

According to this invention, a gas power turbine includes an overhung turbine rotor mounted in bearings in bearing-supporting structure which is mounted on a foundation, the turbine rotor carrying rotor blades, stator blades cooperating with said rotor blades, and means including a main pressure-containing casing within which gas ows to said stator blades to drive the rotor, said main pressure-containing casing being mounted, independently of said bearing-supporting structure, on a foundation by means preventing translation of rotational movement of said main casing relative to the foundation, in each of the six degrees of freedom, but allowing thermal expansion radially and longitudinally of the axis of rotation from a point on said axis.

One embodiment of the invention will now be described by way of example with reference to the accompanying drawings, of which:

FIG. 1 is a section on the vertical centre-line of a gase power turbine,

FIG. 2 is a plan View of the turbine of FIG. 1,

FIG. 3 is a section on the line III-III of FIG. 2,

FIG. 4 is a section on the line IV-IV of FIG. 2,

FIG. 5 is a detail view, and

FIG. 6 is a view on the line VI-VI of FIG. 5.

Referring to the drawings, the turbine comprises bearing-supporting structure 10, in which the turbine shaft 11 is supported by means of two plain bearings 12, and a thrust bearing 13, spaced along the shaft. The overhung turbine rotor 14 is bolted to the shaft 11 which drives an alternator (not shown) through a flanged connection. The structure is mounted on a xed base plate 15, which is secured to a foundation. The turbine has rotor blades 16, and stator blades 17. The latter are supported in a circular assembly in a main casing 20, which forms the principal pressure-containing casing of the turbine. Gas is led to the main casing 20 from a gas source, eg., two simple open-cycle gas turbine engines, through ducts 21 which are bolted to flanges formed on the main casing and on an end closure casing 22. The gas stream is conveyed within inner liners 23 in the ducts 21, cooperating with a corresponding liner 24 within the main casing 20, the latter liner 24 having an annular outlet cooperating with the stator blades 17 The main casing 20 of the turbine is not xed relative to the structure 10, but is mounted in the following way, on the base plate 15.

A pair of axially-spaced flanges 27, 28 are formed on the main casing 20 adjacent the plane of rotation of the rotor and are pin-jointed to a pair of supporting plates 29, 30 by means of pins 31, 32, passing through a bore in an enlarged end of each plate, substantially at opposite sides of the horizontal diameter of the turbine rotor 14. The lower ends of the supporting plates 29, 30 are secured by setscrews to blocks 33, 34, which are in turn secured to the xed base plate 15.

The blocks 33, 34 are each provided with inclined keys 35, 36 which engage in keyways 37, 38 formed between the anges 27, 28 on the main casing 20, one on each side of the casing. The blocks 33, 34 are nally secured to, and located with respect to, the base plate 15 when the main casing 29 has been positioned so that the correct clearances are obtained between the stationary and rotating parts of the turbine.

There is also provided a key 43 which engages with a keyway member 44 secured to the base plate 15 and with an axial keyway cut in the anges 27, 28 at the lower end of the vertical diameter of the main casing 20.

Two tension rods 45 connect the outer casings of the ducts 21 to a pair of torsion bars 46 which are anchored through blocks 47 to base plates 48, which are secured to the same foundation as base plate 15. The free ends of torsion bars 46 are supported in blocks 49 and have levers 50 secured to them by keys. The two ends of each tension rod 45 are secured respectively to a lever 50 and to a duct 21 through pin-and-ball joints allowing limited universal movement. The torsion bars 46 are pre-loaded on assembly so that the levers 50 are vertical when the tension force in rods 45 reaches a predetermined ligure expected in operation.

A further pair of rods 51 is provided, which are connected through spherical joints at their upper ends to the end closure casing 22 substantially on the horizontal centre-line of the turbine, and through spherical joints at their lower ends to the base plate 15. The rods 51 are nearly vertical.

Referring again to FIG. 1, a ring member 52 having grooves containing sealing rings 53 is secured to a flange of the structure 10. The sealing rings 53 engage a vertical face on the end closure casing 22, which is secured by bolting flanges to the main casing 20.

The ring member 52 also has an annular projection 54 which extends into a rebate 55 in the end closure casing 22, the clearance being chosen to permit thermal expansion of the structure 10 (e.g., due to rotation of the alternator with the turbine cold) relative to the casings 20, 22, in addition to permitting thermal expansion of the latter relative to the structure 10, which occurs when the turbine is supplied with high-temperature gas.

In operation, the main casing 20 of the turbine is allowed to move relative to the structure 10 in which the turbine rotor 14 is located, the ring member 52 being capable of moving independently of the end closure casing 22 while the sealing rings 53 remain in sealing contact.

The turbine rotor 14 is mounted through the structure 10, directly on the base plate 15.

The main casing 20, on the other hand, is mounted independently; its weight is supported by rst means including plates 29, 30, which also locate the main casing against vertical translational movement and against torsional loads (i.e., against turning about the rotational axis of the turbine). A small proportion of its weight may also be supported by rods 51.

The axial position of the main casing 2G is determined by second means including the keys 35, 36, which oppose end loads on the main casing and locate it against axial translational movement, and against turning about a vertical axis.

End loads, especially those acting on the outer casings f the ducts 21, are also opposed by the assemblies including tension rods 45, levers 50, and torsion bars 46. It will be appreciated that the fact that a large mass of gas at high velocity is turned from its initial direction of travel (upwards in FIG. 2) through approximately 180 before owing through the turbine (downwards in FIG. 2) results in a large reaction (acting substantially upwards in FIG. 2) which is transmitted through the outer casing ofl duct 21 and through the end closure casing 22 and main casing 20.

The main casing 20 is centralised, i.e., located in the horizontal plane relative to the base plate 15, by third means including the key 43 which withstands lateral forces and locates the main casing against transverse translational movement.

The main casing 20 is located against rocking about a transverse horizontal axis by fourth means including the rods 51.

What I claim as my invention and desire to secure by Letters Patent is:

1. In a turbine including an overhung turbine rotor comprising a turbine disc, a plurality of rotor blades secured to said turbine disc, and a shaft, said turbine disc being secured to an end of said shaft; a bearing-supporting structure; a foundation; said bearing-supporting structure being mounted on said foundation; means rotatably to mount said overhung turbine rotor in said bearingsupporting structure; a main pressure-containing casing mounted on said foundation; stator blades mounted within said main pressure-containing casing and cooperating with said rotor blades; and gas supply means which supplies gas through said main pressure-containing casing and said stator blades to said rotor blades to drive said rotor; load bearing and locating means positioning and supporting said main pressure-containing casing on said foundation independently of said bearing-supporting structure, said load bearing and locating means including:

(i) a pair of transverse ianges, one on each side of said main pressure-containing casing, a pair of supporting plates one on each side of said'main pressurecontaining casing, each said supporting plate having an upper end and a lower end, means pin-jointing said upper ends to said transverse flanges, and means securing said lower ends to said foundation;

(ii) a rod connected between a point on said main pressure-containing casing, said point being axially spaced from said supporting plates and a point on said foundation; and

(iii) iirst key-and-keyway means disposed in a plane Yat right angles to the axis of rotation of said overhung turbine rotor, and second axially-disposed keyand-keyway means arranged on the vertical centreline of said turbine, one element of said key-andkeyway means being formed on said main pressurecontaining casing and the other element of each said key-and-keyway means being fixed with respect to said foundation; Y said load bearing and locating means being capable of allowing relative thermal expansion Vof said main pressure-containing casing relative to said bearing-supporting structure, whilst being capable of preventing translational and rotational movement of said main pressure-containing casing relative to said foundation in each of the six degrees of freedom.

2. In a turbine, the improvement as clamied in claim 1 further comprising:

(i) a radial ange formed on said bearing-supporting structure; t

(ii) a radial end-face formed on said main pressurecontaining casing;

(iii) gas sealing means provided between said bearingsupporting structure and said main pressure-containing casing;

said gas sealing means comprising a ring member secured to the radial flange formed on said bearing-supporting structure, a pluralityrof annular grooves formed in said ring member and a plurality of sealing rings each retained in a respective annular groove and engaging said radial end-face formed on said main pressurecontaining casing; said gas sealing means being capable of allowing relative expansion of said bearing-supporting structure and said main pressure-containing casing in a direction at right angles to the axis of rotation of said overhung turbine rotor.

3. In a turbine, the improvement as claimed in claim 1 further comprising thrust relieving means including (i) a pre-loaded torsion bar having two ends;

(ii) a lever having two ends; and

(iii) atension member;

one end of said pre-loaded torsionV bar being ixed relative to said foundation, one end of said lever being secured to the other end of the pre-loadedV torsion bar, and said tension member being connected between the other end of said lever and said main pressure-containing casing, whereby said thrust relieving means is capable of relieving an axial thrust imposed on saidmain pressurecontaining casing by gas forces acting thereon.Y

4. In a turbine, the improvement as claimed in claim 1 further comprising:

(i) a radial ange formed on said bearing-supporting structure;

(ii) a radial end-face formed on said main pressurecontaining casing;

(iii) gas sealing means provided between said bearingsupporting structure and said main pressure-containing casing;

said gas sealing means being capable of allowing relative expansion of said bearing-supporting structure and said main pressure-containing casing in a direction at right angles to the axis of rotation of said overhung turbine rotor.

References CitedV UNITED STATES PATENTS 2,789,787 4/1957 Jarlborg, 253-78 2,828,939 4/1958 Grey 253-39 3,036,375 5/1962 Schlosser et al. 248-19 X 3,072,380 l/1963 Hennig 253-78 X EVERETTE A. POWELL, JR., Primary Examiner.

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