US3304054A

US3304054A - Housing for a gas or steam turbine

Info

Publication number: US3304054A
Application number: US516538A
Authority: US
Inventors: Oechslin Konrad; Moser Paul
Original assignee: Escher Wyss AG
Current assignee: Sulzer Escher Wyss AG
Priority date: 1965-01-12
Filing date: 1965-12-27
Publication date: 1967-02-14
Anticipated expiration: 1984-02-14
Also published as: CH421142A; FR1459676A; DE1426801A1; BE674025A; NL6517281A; GB1137512A

Description

Fell 14, 1967 K. oEcHsLlN ET AL HOUSING FOR A GAS OR STEAM TURBINE Filed Deo. 27, 1965 United States Patent O land Filed Dec. 27, 1965, Ser. No. 516,538 Claims priority, application Switzerland, llan. 12, 1965, 372/65 16 Claims. (Cl. 253-39) This invention relates to a housing for a -gas or steam turbine, having an outer housing and an inner housing, fthe latter comprising a stationary guide apparatus, a partition separatin-g the intermediate space between inner and outer housing into an inlet-side intermediate space and an outlet-side intermedaite space, and a supporting eletment for the inner housing.

Housings of this kind, as is known, are used more particularly when the working medium under pressure has high temperatures. The inner housing then serves for guiding the flow of working medium and as Sup-port for the guide 'blades of the turbine, and the intermediate space between the housings contains a heat insulating material, the inner housing taking up substantially the inner temperature, and the outer housing the inner pressure.

The connection between the outer housing and that part part of the inner housing which receives the guide blades must take up the temperature `gradient occurring between the housings, as well as the forces acting axially on the `guide blades in the direction of the outlet-side, and at the same time, keep the lguide -blades as far as possible in the same position in relation to the moving blades.

Flange holding means are known, lin which the flange is provided on the outlet-side end of the inner housing portion receiving the guide blades, and at the same time forms the partition between the inlet-side intermediate space and the outlet-side intermediate space between the housings. This embodiment, apart from the advantage of the axially compact construction, has considerable disadvantages. The rotor shaft is `advantageously mounted on the inlet-side axially outside the turbine housing, and if necessary is cooled from that side up to the first guideblade ring exclusive.

In operation, the rotor is heated substantially from the first moving-'blade ring onward, and expands axially from that place in the direction towards the outlet-side of the turbine. The inner housing portion, receiving .the guide blades and heated in like manner in operation is, on the contrary, xed by its outlet-side end to the holding ange, and is fixed by means of the latter relatively to the outer housing, and the inner housing portion receiving .the guide blades therefore expands axially -towards the inlet-side. The effect of this is that the moving-blade apparatus and the guide-blade apparatus expand in opposite directions and correspondingly produce a considerable axial displacement of the moving blades and guide blades in relation to each other, which results in a danger of stripping, inadmissibly increases the radial play at the outer, conical -moving blades and interferes with the accommodation of a sufficient number of labyrinth joints between -guide wheels and rotor. Another important disadvantage lies in the considerable accumulation of material in the holding flange, which has to take up a considerable temperature gradient, resulting in a risk of the inner housing becoming non-circular in its region receiving the guide blades.

It has been proposed to arrange, coaxially with the inner housing portion receiving the guide blades, as supporting element, a thin frusto-conical shell, provided with holes and consisting of material of low thermal conductivity, the wider end of which conical shell is fixed to the partition and its narrower end to the inlet-side end of the inner housing portion receiving the .guide blades, the inner housing 'being axially displacea-ble in relation to the partition. This embodiment obviates displacement of the moving and guide blades in relation to each other, but the inner housing portion receiving the guide blades is subjected to tension, so that it is only possible to use an inner housing construction which is capable of taking up tensile forces.

It is the object of the invention to overcome the hereinbefore described drawbacks. For this purpose, a turbine housing of the kin-d hereinbefore described is developed, according to the invention, in that the inlet-side narrower end of the truste-conical shell carries the inletside end of a substantially cylindrical supporting ring, which surrounds the inner housing at least over part of the portion of the latter receiving the guide blades, and the outlet-side end of which carries the inner housing, the frusto-conical shell in the manner known per se, and/or the supporting ring having openings in the part thereof situated in the linlet-side intermediate space.

A constructional example of the subject of the invention is shown in simplified form in the drawing, in which:

FIG. l shows an axial section through a housing of a gas turbine, and

FIG. 2 shows a portion of a section at right angles to the axis on the line II--ll in FIG. 1.

The turbine housing has an outer housing 1 and an inner housing, which on the inlet side comprises the inlet part 2 and the port-ion 4 receiving the guide blades 3. 5 denotes t-he rotor carrying the discs 6 with the moving blades 7. Both the inlet-side part 8 and the outlet-side part 9 of the intermediate space between the housings is filled with heat insulating material 10. An axially fast, two-part ring 12, centred in the outer housing 1 by tour cotters 11 and four lugs 13, each secured to a block 14, connected to the ring 12 by screws, not shown, whic-h lugs by means of four cotters 15 centre a two-part ring 16 belonging to the axial portion 4 of the inner housing, form together with a sealing rin-g 17 of known construction a partition between the inlet-side part 8 an-d the outlet-side part 9 of the intermediate space between the housings, the ring 16 being axially displaceable relatively to the partition 12, 13, 17.

The sealing ring 17, in known manner, consists of an outer ring 18, mounted axially fast in a sealing manner in the outer housing 1, and an inner ring 19, co-axial with said ring 18 and secured to the outlet-side end of ring 16, the co-axial play provided between rings 18, 19 being bridge-d by a thin, one-part diaphragm 20.

A two part frusto-conical shell 21 is secured as supporting element by its wider orifice to the ring 12. This frusto-conical shell 21 has a thin wall thickness and consists of austenitic material of low thermal conductivity.

The rotor 5 is mounted axially outside the turbine, not shown in the drawing, in an air compressor, assembled with it. A gap 22, recessed between the rotor shaft and a tubular part of the outer housing 1 allows cool working medium from the air compressor to flow along the rotor shaft to the first guide-blade ring. The inlet part 2 of the inner housing is centred radially and axially movable in the cold compressor housing 24 by means of four cotters 23, and the inner housing portion 4 receiving the guide blades 3 is centred radially and axially movable in the region of its inlet-side end by means of four cotters 25.

The truste-conical shell 21, at its narrow inlet-side end, has a iiange 26 and by means thereof carries the inlet-side end of a two-part cylindrical supporting ring 27, the latter being connected to the flange 26 by screws 28. The outlet-side end of the supporting ring 27 is connected to the ring 16, which is situated on the outlet-side of the last guide blade ring and surrounds the last moving blade ring. Of the total of iive guide-blade rings and tive moving-blade rings, the supporting ring 27 together with the ring 16 surrounds the three outermost guide and movingblade rings situated downstream. The supporting ring 27 has longitudinal slots 29, the Wall parts between the longitudinal slots in the peripheral direction being a multiple of the wall thickness, and the space bounded by the frusto-conical shell 21, the supporting ring 27 and the sealing ring 17 being also lilled with heat insulating material 10.

During operation of the turbine, the rotor with the discs 6 and the moving blades 7 ixed to the latter is heated by the hot working medium and expands axially in the direction towards the outlet-side of the turbine. The inner-housing portion 4 receiving the guide blades 3 is also heated mostly by the working medium flowing through the guide blades and moving blades, and to a lesser extent by the heat passing through the inlet par-t 2 of the inner housing through the insulating material 10. The supporting ring 27 is heated mostly by the ring 16, and to a lesser extent by the heat passing from the inner housing through the' insulating material 10, so that it has approximately the same temperature as the inner-housing portion 4 receiving the guide blades. The maximum temperature, namely that of the supporting ring 27, is imparted to the frustoconical shell 21 at its line of contact with the iiange 26, while its lowest temperature, substantially corresponding to the temperature of the outer housing 1, lies on its line of contact with the ring 12. The effect of this is that the axial expansion of the frusto-conical shell 21 remains within insignificant limits, like that of the known embodiment, and that the region of the ange 26 is displaced by an insigniticant amount only, in the direction towards the inlet-side of the turbine. Since, inthe region of the innerhousing portion `4 receiving the guide blades, this portion 4 as Well as the supporting ring 27 are heated essentially approximately equally, and :all these parts consist of material having the same thermal expansion, the guide blades 3 and moving blades 7 of the turbine remain inapproximately the same axial position relatively to each other Within theV entire working range. Thevthermal expansion of the frusto-conical shell 21 may be reduced additionally in manner known per se by means of holes therein, and the thermal expansion of the supporting ring 27 may be increased by omitting insulating material between supporting ring and inner housing, and in this Way, minimum relative displacement between guide-blade apparatus and moving-blade apparatus is effected.

Different radial thermal expansions of the inlet-side and outlet-side ends of the supporting ring 27, due to different temperatures in these regions, do not load the supporting ring inadmissibly, on account of the longitudinal slots 29 in the latter.

The axial thrust acting on the guide blades 3, or on the inner-housing portion 4 receiving said blades, during the operation of the turbine, in the direction towards the outlet-side is transmitted by the ring 16 to the supporting ring 27, by the latter to the frusto-conical shell 21 and by the latter to the outer housing 1. Due to the step according to the invention of the use of a supporting ring, the innerhousing portionl receiving the guide blades is subjected exclusively to compression stresses.

The guide blades 3 are mounted in tive two-part guideblade rings 30, the corresponding halves being connected together by screws 31. Between each pair of adjacent guide-blade rings, there is arranged one of a total of four one-part intermediate rings 32. Each of these four intermediate rings 32 surrounds a moving-blade ring 6, 7, and the outlet-side last moving-blade ring of the total of five such rings is surrounded by the ring 16, which has an inner radial groove 33, in which 4an outer radial key 34 of the outlet-side last guide-blade ring is held fast axially. The said outlet-side last guide-,blade ring is centred 4 radially movable in the ring 16 by means of four cotters 35', which cotters also transmit the torque of the innerhousing portion 4, carrying the guide blades, to the ring 16.

The intermediate rings y32 have on each end face an inner rim 35,which engages with close t a corresponding recess 36 of the respectively contiguous guide-blade ring 30, whereby each guide-blade ring is centred relatively to the intermediate ring immediately adjacent it. Each guide-blade ring 304 has an outer peripheral groove 37. Each intermediate ring 32 is connected to the two adjacent guide-blade rings 30 by means of screwbolts 38 passing throughthe intermediate -ring 32 and extending into the peripheral grooves 37 of the guide-blade rings 30, the nuts of the screwbolts 38 lying in the peripheral grooves 37 of the guide-blade rings 30, The rings 30, 32, 30, connected together in each case by a ring of such screwbolts, are connected together non-rotatably, by a ring of axial cotters 39, which extend over all three rings and are accommodated in axially flush grooves 40.

Non-circularity of the individual guide-blade rings'30 on heating, due to their two-part construction, and owing to the irregularity of the cross section of the material in the peripheral direction at the joints of the two halves, necessarily associated with such construction, is kept within-negligibly small limits by the one-part intermediate rings 32, or the mutual centring of the guide-blade rings relatively to the intermediate rings.

Due to the thrust of the individual guide-blade rings occurring inthe direction towards the outlet-side on operation of the turbine, the individual rings 30, 32 are pressed against the rings which, seen from the position of the ring in question, are on the outlet-side of them, and the latter are pressed against the ring 16 supported axially in the outer housing 1 through the supporting rin-g 27 and the frusto-conical shell 21, the screwbolts 38 having no important tensile forces to take up.

From the hot ring 16, which is connected in a good heat-conducting manner with the rings 30, 32, only a little heat iiows through the lugs 13 and the diaphragm 20 to the cold outer housing 1, so that inl this region, no important thermal stresses are set up, which could produce a deformation.

The high stability of the inner-housing portion receiving the guide blades makes it possible to construct this portion of light weight and with comparatively thin walls, whereby a considerable saving in heat-resistant material is eiected.

The development of the inner housing portion receiving the guide blades according to the invention thus provides, with slight expenditure in material, a very stable construction, which is subjected to little deformation and remains circular to a considerable extent.

What is claimed is:

1. In an axial flow gas or steam turbine, an outer housing and an inner housing, said housings confining an intermediate space; heat insulating material disposed in said intermediate space; a plurality of axially spaced circular series of inwardly extending guide blades arranged over an axial portion of said inner housing; said axial portion of said inner housing and said guide blades thus forming a stationary-guide apparatus; a partition separating said intermediate space into an inlet-side intermediate space and an outlet-side intermediate space; means for connecting axially fast in a sealing manner and for centering said partition non-rotatably relatively to said outer housing; means for centering and for connecting in a sealing manner said inner housing to said partition to be axially displaceable relatively to the latter; a supporting element for supporting said inner housing, having a thin-walled frusto-conical shell consisting of material of low thermal conductivity, arranged in 4said inlet-side intermediate space, co-axial with said inner housing, -its wider end facing said partition, and means for connecting axially fast and for centering non-rotatably said wider end lof said frusto-conical shell relatively to said outer housing, and a substantially cylindrical supporting ring, co-axial with said inner housing and surrounding the latter at least over part of `said guide apparatus, the inlet-side end of said supporting ring being rigidly connected to the narrower end of said frusto-conical shell, and means for connecting axially fast and for centering non-rotatably the outlet-side end of said supporting ring relatively to said inner housing; and openings in the portion of the walls of said supporting element lying Within said inlet-side intermediate space.

2. The combination defined in claim 1 in which the outlet-side end of said supporting ring is connected With the outlet-side end of said guide apparatus.

3. The combination defined in claim 1 in which said partition is connected with the outlet-side end of said guide apparatus.

4. The combination defined in claim 1 in which said supporting ring has longitudinal slots.

5. The combination defined in claim 4 in which the Wall parts of said supporting ring between said longitudinal slots in the peripheral direction amount to a multiple of the Wall thickness.

6. The combination defined in claim 1 in which said partition comprises a ring; inwardly extending lugs fixed at said ring having at their inner ends cotters for centering said inner housing; a sealing ring for bridging the openings left free by said lugs, said sealing ring comprising an outer ring mounted axially fast in a sealing manner on said ring and an inner ring co-axial with said outer ring and mounted axially fast in a sealing manner on said inner housing, and a thin corrugated one-part diaphragm bridging the co-axial play between said rings of said sealing ring.

7. The combination described in claim 1 in which said means for connecting axially fast in a sealing manner and for centering non-rotatably said partition relatively to said outer housing comprise an inner peripheral groove in said outer housing, the axially outer portion of said partition engaging with close axial fit in said groove, and cotters.

8. The combination defined in claim 1 in which said means for connecting axially fast and for centering nonrotatably said wider end of said -frusto-conical shell relatively to said outer housing comprises a ring rigidly connected with said wider end of said frusta-conical shell, a inner peripheral groove in said outer housing, said ring engaging with close axial fit in said groove, and cotters.

9. The combination dened in claim 1 in which said wider end of said frusto-conical shell is rigidly connected to the axially outer portion of said partition.

10. The combination defined in claim 1 in which said means for connecting axially fast and for centering nonrotatably said outlet-side end` of said supporting ring relatively to said inner housing comprise a radial groove in one of said two parts and a corresponding radial key in the other of said two parts, said key engaging with close axial fit in said groove, and cotters.

11. The combination defined in claim 1 in which said outer housing, the portions of said inner housing lying on the inlet-side and on the outlet-side of said guide apparatus, the radially outer portion of said partition, and said supporting element are diametrically split.

12. The combination defined in claim 1 in which said guide apparatus is diametrically split.

13. The combination defined in claim 1, in which said guide apparatus comprises a plurality of axially spaced diametrically split two-part guide-blade rings each receiving one of said circular series of guide blades, a plurality of one-part intermediate rings, arranged so as to alternate contiguously with said guide-blade rings, and means for centering and for non-rotatably connecting said rings relatively to each other.

14. The combination defined in claim 13 in which one of two immediately adjacent rings has, on its end face facing the other ring, a rim, and the other ring has, on its end face facing the former ring, a corresponding recess, said rim engaging with close fit Iin said recess, so as to center said adjacent rin-gs relatively to each other.

15. The combination defined in claim 13 in which said means for non-rotatably connecting said rings relatively to each other comprise axially extending screws and cotters.

16. In an axial fiow gas or steam turbine, a diametrically split two-part outer housing and an inner housing, said housings confining an intermediate space; heat insulating material disposed in said intermediate space, said inner housing comprising a diametrically split two-part inletportion, a guide apparatus portion and a diametrically split two-part outlet-portion; said guide apparatus portion comprising a plurality of axially spaced .diametrically split two-part guide-blade rings each having a circular series of inwardly extending guide blades; a plurality of one-part intermediate rings, arranged so as to alternate contiguously with said guide-blade rings; said rings thus forming a stationary guide apparatus; said intermediate rings having on their end faces an inner rim, and said guide-blade rings having on their end faces facing one of said intermediate rings a corresponding recess, each of said rims engaging with close fit in the corresponding recess so as to center said guide-blade rings and said intermediate rings relatively to each other; each of said guide-blade rings having an outer peripheral groove; each of said intermediate rings being connected axially fast and non-rotatably to each other to the two immediately adjacent guide-blade rings by a circular series of axial screwbolts passing through the intermediate ring and extending into said outer peripheral :grooves of the guideblade rings, the nuts of the screwbolts lying in said grooves, and by cotters; a partition separating said intermediate space in an inlet-side intermediate space and in an outlet-side lintermediate space; said partition comprising a diametrically split two-part ring, inwardly extending lugs fixed at said ring having at their inner ends cotters for centering deplaceably in axial direction the outletside end of said guide apparatus, a sealing ring comprising a one-part outer ring mounted axially fast in a sealing manner in said outer housing and a one-part inner ring co-axial with said outer ring and mounted rigidly in a sealing manner on said outlet-side end of said guide apparatus, so as to connect said partition in a sealing manner with said outlet-side end of said guide apparatus, and a thin corrugated one-part daiphragm bridging the coaxial play between said two rings of said sealing ring; an inner peripheral groove in said outer housing in which the radially outer part of said two-part ring of said partition and the radially outer part of said one-part outer ring of said sealing ring engage, the former axially adjacent at the inlet-side end face of the other, with close axial fit in said inner peripheral groove of said outer housing, thus connecting said two-part ring of said partition and said one-part outer ring of said sealing ring axially fast in a sealing manner with said outer housing, and cotters for centering non-rotatably said two-part ring of said partition relatively to said outer housing; a supporting element for supporting said inner housing, having a frusto-conical thin-walled shell consisting of material of low thermal conductivity, its Wall having openings, arranged in said inlet-side intermediate space, co-ax-ial with said guide apparatus, its Wider end rigidly connected to said two-part ring of said partition so as to be connected axially fast and centered non-rotatably relatively to said outer housing, a cylindrical supporting ring, having longitudinal slots, its wall parts between said longitudinal slots in the peripheral direction amounting to a multiple of the wall thickness, co-axial with said guide apparatus, and surrounding the latter over its outlet-side part, the narrow end of said frusto-conical shell being rigidly connected to the inlet-side end of said supporting ring, a two-part con- 7 8 nection ring being rigidly connected tothe outlet-side end cotters for centering non-rotatably said ends of said parts of said supporting ring and at the saine time axially and relatively to each other. radially neighbouring the outlet-side last of said guidey blade rings, said connection ring thus forming said outlet- References Cited by he'EXaIIlillel' side end of said guide apparatus, said outlet-side last of 5 UNITED STATES PATENTS said guide blade rings having an outer radial key, and said 2,445,661 ,H1948 Constant et al.

connection ring having an inner radial groove, said key engaging with close axial t in said groove, so as to con- MARTIN P SCHWADRON prima] Examiner nect axially fast said outlet-side end of said supporting v y ring to said outlet-side end of said guide apparatus, and 10 E. A. POWELL, JR., Assistant Examiner-

Claims

1. IN AN AXIAL FLOW GAS OR STEAM TURBINE, AN OUTER HOUSING AND AN INNER HOUSING, SAID HOUSINGS CONFINING AN INTERMEDIATE SPACE; HEAT INSULATING MATERIAL DISPOSED IN SAID INTERMEDIATE SPACE; A PLURALITY OF AXIALLY SPACED CIRCULAR SERIES OF INWARDLY EXTENDING GUIDE BLADES ARRANGED OVER AN AXIAL PORTION OF SAID INNER HOUSING; SAID AXIAL PORTION OF SAID INNER HOUSING AND SAID GUIDE BLADES THUS FORMING A STATIONARY GUIDE APPARATUS; A PARTITION SEPARATING SAID INTERMEDIATE SPACE INTO AN INLET-SIDE INTERMEDIATE SPACE AND AN OUTLET-SIDE INTERMEDIATE SPACE; MEANS FOR CONNECTING AXIALLY FAST IN A SEALING MANNER AND FOR CENTERING SAID PARTITION NON-ROTATABLY RELATIVELY TO SAID OUTER HOUSING; MEANS FOR CENTERING AND FOR CONNECTING IN A SEALING MANNER SAID INNER HOUSING TO SAID PARTITION TO BE AXIALLY DISPLACEABLE RELATIVELY TO THE LATTER; A SUPPORTING ELEMENT FOR SUPPORTING SAID INNER HOUSING, HAVING A THIN-WALLED FRUSTO-CONICAL SHELL CONSISTING OF MATERIAL OF LOW THERMAL CONDUCTIVITY, ARRANGED IN SAID INLET-SIDE INTERMEDIATE SPACE, CO-AXIAL WITH SAID INNER HOUSING, ITS WIDER END FACING SAID PARTITION, AND MEANS FOR CONNECTING AXIALLY FAST AND FOR CENTERING NON-ROTATABLY SAID WIDER END OF SAID FRUSTO-CONICAL SHELL RELATIVELY TO SAID OUTER HOUSING, AND A SUBSTANTIALLY CYLINDRICAL SUPPORTING THE LATTER AT LEAST SAID INNER HOUSING AND SURROUNDING THE LATTER AT LEAST OVER PART OF SAID GUIDE APPARATUS, THE INLET-SIDE END OF SAID SUPPORTING RING BEING RIGIDLY CONNECTED TO THE NARROWER END OF SAID FRUSTO-CONICAL SHELL, AND MEANS FOR CONNECTING AXIALLY FAST AND FOR CENTERING NON-ROTATABLY THE OUTLET-SIDE END OF SAID SUPPORTING RING RELATIVELY TO SAID INNER HOUSING; AND OPENING IN THE PORTION OF THE WALLS OF SAID SUPPORTING ELEMENT LYING WITHIN SAID INLET-SIDE INTERMEDIATE SPACE.