US3162421A

US3162421A - Gas turbine construction

Info

Publication number: US3162421A
Application number: US167141A
Authority: US
Inventors: Schwarz Gottfried
Original assignee: Kuehnle Kopp and Kausch AG
Current assignee: Howden Turbo GmbH
Priority date: 1961-01-24
Filing date: 1962-01-18
Publication date: 1964-12-22
Anticipated expiration: 1981-12-22
Also published as: CH390948A; AT239607B; GB925968A; BE609161A

Description

1964 s. SCHWARZ 3,162,421

GAS TURBINE CONSTRUCTION Filed Jan. 18, 1962 4 Sheets-Sheet 1 INVENTOR fW -IM faw-wj Attorney fiuMaM Dec. 22, 1964 Filed Jan. 18, 1962 G. SCHWARZ GAS TURBINE CONSTRUCTION 4 Sheets-Sheet 2 11 8 I T T r 1 :1

INVENTOR= %M/-M LAX/a G. SCHWARZ GAS TURBINE CONSTRUCTION Deg. 22, 1964 4 Sheets-Sheet 3 Filed Jan. 18, 1962 INVENTOR GQ/f/f/ef d ILA/"Q IL Dec. 22, 1964 G. scHwARz $162,421

GAS TURBINE CONSTRUCTION Filed Jan. 18, 1962 4 Sheets-Sheet 4 FIG.6

INVENTOR 6 0 /fl d United States Patent 3,162,421 GAS TURBINE QQNSTRUQTION Gottfried Schwarz, Gberursei, Taunus, Germany, assignor to Alttiengesellschait Kiihnle, Kopp & Kausch, Frankenthal, lfalz, Germany Filed Jan. 18, I962, Ser. No. 167,141 Claims priority, application Germany, Jan. 24, 1961, A $5,565 14 Claims. (Cl. 253-52) The present invention relates to a gas turbine construction, and more particularly to a stator guide vane arrangement permitting an adjustment of the guide vanes.

One object of the present invention is to provide an adjustable stator guide vane arrangement permitting the control of the angle at which a gas or fluid is guided by the guide vanes into the rotor passages.

Another object of the present invention is to provide a stator guide vane arrangement permitting an adjustment of the guide vanes in such a manner that the effective flow cross sections of the passages between adjacent guide vanes can be varied.

Apparatus serving this purpose is known, but the prior art construction have the disadvantage that the guide vanes are mounted for turning movement, and have to be individually turned on pivot means, which causes wear and tear reducing the useful life of the apparatus.

It is consequently an important object of the present invention to provide an adjustable guide vane arrangement in which all guide vanes are rigidly mounted on supporting stator members.

Another object of the present invention is to provide a guide vane arrangement in which two sets of guide vanes are provided which can be shifted relative to each other to form difierent composite vane means.

It is also an object of the present invention to improve the stator guide van construction of a radial flow turbine, and particularly of a radial fiow turbine in which the fluid flows inwardly through stator guide vanes to an inner rotor.

With these objects in view, one embodiment of the present invention relates to a turbine stator which comprises a first stator member including an annular row of first guide vane means, a second stator member including an annular row of second guide vanes, and operating means for moving one of the stator members between a first end position and a second end position.

In the first end position, each second guide vane means abuts one first guide vane means and forms a first composite vane means with the same. In the second end position, each second guide vane means abuts another first guide vane means and forms with the same another composite vane means which is differently shaped from the composite vanes means obtained in the first end position. Consequently, the flow of fluid between the composite vane means is differently controlled in the first and second end positions due to the fact that the two composite vane means have different profiles, extend at different angles, and define free passages having different effective flow cross sections between each other.

In the preferred embodiment of the invention, the first and second stator members are concentric rings, and the inner stator ring member is turnable with the second guide vane means. Each second guide vane means is located between confronting surfaces of two adjacent first guide vane means partly overlapping with the same and partly located downstream of the same. In the first end position, the upstream surface of each second guide vane means abuts the downstream surface of one adjacent first guide vane means, and in the second end position, the downstream surface of each second guide vane means abuts the upstream surface of the respective other adjacent 3,162,421 Patented Dec. 22, 1964 first guide vane means. In the second end position, the upstream surface of each second guide vane means extends the upstream surface of the respective first guide vane means in downstream direction. The narrowest flow cross section of each passage between adjacent composite vane means is located between the downstream surface (i.e. the surface facing the rotor) of the respective first guide vane means and the downstream end of the upstream surface (i.e. the surface overted from the rotor) of the respective second guide vane means, regardless in which end position the turnable second stator member is.

The composite vane means are differently inclined in the two end positions, so that the fluid is guided at different angles into the rotor of the turbine. In this manner, it is possible to adapt the direction in which the fluid is guided by the stator guide vane means, and in which the fluid enters the rotor, to the prevailing operational conditions. Since the free flow cross sections of the passages between adjacent composite vane means are also different in the two end positions, the amount of fluid flowing through the stator is also varied in accordance with the prevailing conditions.

While the arrangement is most effective in the two end positions of the turnable second guide vane means, a variation of the direction of flow, and of the amount of fluid flowing through the guide vanes, is also obtained in the intermediate positions of the second guide vanes in which they do not abut the adjacent first guide vanes. In such intermediate positions, the angle of the direction of flow, and the amount of fluid flowing through the guide vanes, are intermediate values between the values obtained in the end positions in which composite vane means are formed by the first and second guide vanes.

It is contemplated to mount both stator members with the respective first and second guide vane means for turning movement relative to each other. However, it is preferred to mount one stator member with the set of first guide vanes stationarily, and to mount the other stator member, preferably the stator member carrying the downstream located second guide vane means for turning move ment relative to the first stator member and its first guide vane means. It is also possible to provide additional turnable stator members carrying circular rows of third or fourth guide vane means and to make the additional stator members turnable between end positions corre- 'sponding to the end positions of the above described second stator member.

In the preferred embodiment of the invention, the turnable stator member is located inwardly of the fixed stator member, and surrounds the rotor of a radial flow turbine. In the above mentioned modified embodiment of the invention, a third stator member with a circular row of third guide vane means is located between the second guide vane means and the rotor, and surrounds the rotor so as to be shiftable to a position extending the second guide vanes inwardly. The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a side elevation of a radial flow turbine according to one embodiment of the invention;

FIG. 2 is a vertical axial sectional view of the turbine shown in FIG. 1;

FIG. 3 is a fragmentary schematic cross sectional view on a reduced scale and taken on line LIL-III in FIG. 2;

FIG. 4 and FIG. 5 are fragmentary cross sectional views taken on line IIIIII in FIG. 2 and illustrating on averted from the rotor.

i an enlarged scale two different operational positions of the stator vane arrangement of the invention; and

FIGS. 6 and 7 are fragmentary cross sectional views corresponding to FIGS. 4 and and illustrating a modified stator guide vane arrangement of the invention.

1 Referring now to the drawings, and more particularly to FIG. l, a base and bearing housing 1 supports the rotor shaft, 2 of a radial fiow exhaust gas turbine which may be used as a prime mover for driving a machine.

The turbine housing 3 includes a spiral duct 5 having an inlet opening 4, and supplying the gas to a circular row 'of outer guide vane means 12, as best seen in FIG. 2. Shaft 2 carries a rotor 11 through which the gas flows in inward direction until it is discharged through the central outlet 6.

The stator of the turbine includes a stationary annular member 14 on which the circular row of 'outer guide vane means is fixedly mounted. A second stator member 16 is turnably mounted on a tubular projecting part 17 of the rear wall 8 of the turbine housing. Stator member 16 has an annular part on which a row of inner guide vane means 13 is fixed. The relative position, and the general arrangement, of the outer guide vane means 12 and of the inner guide vane means 13 is best seen in FIG. 3.

Between the tubular projection 17 and shaft 2, a packing 18 is located. Another packing is located between the peripheral flange 19 of stator member 16, and a tubular projection 20 of rear wall 8.

The turnable stator member 16 has a projecting pin 21 carrying a roller 22. A shaft 9 is turnaoly mounted in rear wall 8, and has a forked arm fixed thereto by a pin 24, and embracing roller 22. The other end of shaft 9 fixedly carries an arm 10 so that

members

23, 9 and 10 form a double-armed lever. When lever arm 10 is turned by manual operation, the forked lever arm 23 effects an angular displacement of the turnable stator member 16 together with the circular row of inner guide vane means 13 so that guide vane means 13 are displaced relative to the outer guide vane means 12.

As best seen in FIG. 3, each guide vane means 12, and each guide vane means 13 has an upstream surface and a downstream surface, since the fluid flows in inward direction through the passages between adjacent guide vane means. Each inner guide vane means 13 is located between two confronting surfaces of the two guide vane means 12 adjacent thereto, and overlaps the respective outer guide vane means 12 so that only a part of each inner guide vane means 13 is located downstream and inwardly of the respective outer guide vane means 12.

The fragmentary schematic views of FIGS. 4 and 5 illustrate the relative positions of the outer and inner guide vane means in the two end positions of

stator member

16, 15, which are obtained by turning operating means 10, 9, 23. The outer guide vane means 12 are designated 120a, 120b, 1200, and the inner guide vane means 13 are designated 121a, 121b, 121a. The lateral surfaces 124a, 1241), 1240 face upstream i.e. these surfaces are The

lateral surfaces

125a, 125b, 125:: face in downstream direction toward the rotor, 'i.e., these surfaces face the rotor.

The inner guide vane means 13 have

lateral surfaces

126a, 126b, 126a facing upstream averted from the rotor and the

lateral surfaces

127a, 127b, 1270 facing downstream toward the rotor facing the rotor.

In the first end position of the

turnable stator member

15, 16,-guide vanes 13 are in the position shown in FIG. 4 in which the upstream surfaces thereof partly abut the downstream surfaces of the coresponding outer vane means on one side thereof. In the other end position of turnable stator membenIS, 16, the

downstream surfaces

127a and 127b respectively abut the upstream surfaces 124i) and 124s of the outer guide vane means, as shown in FIG. 5.

In the end position of FIG. 4, the inner guide vane means 121a forms with the outer guide vane means a a composite vane means having a certain profile, while in the other end position the inner guide vane means 121a forms with the outer guide vane means 12% another com posite vane means having a different profile.

In the position of FIG. 4, the inner guide vane means are almost completely covered by the outer guide vane means, whereas in the position of FIG. 5, the inner guide vane means project inwardly from the respective outer guide vane means so that the thus formed composite vane means is more elongated, and extends at a different angle with respect to a radial vector or plane passing through the axis of the rotor, as, compared with the composite vane means obtained in the position of FIG. 4. Either composite vane means has a substantially streamlined shape for guiding the fluid in the'passages formed between adjacent composite vane means.

The narrowest effective cross section B between two adjacent composite vane means in the position of FIG. 4 is located between the inner

downstream surface

125a, 125b,.125c of the outer guide vane'means, and the inner end 128b, 1280 etc. of the inner guide vane means. In the position of FIG. 5, the narrowest effective flow cross section B is located between the inner downstream surface 125bof the outer guide vane means, and the inner end 1281) of the respective inner guide vane means. The flow cross section B is substantially greater than the flow cross section B.

The median flow direction 122 in the position of FIG. 4, and 122' in the position of FIG. 5 extends at different angles [3 and B with respect to tangential planes on circles concentric with the circular rows of guide vanes. In the positions of FIGS. 4 and 5, a variation of the flow cross sections of about 45% is obtained. The inner guide vanes are also effective in the intermediate positions in which they are spaced from the outer guide vanes, and vary the effective flow cross sections while maintaining a good efficiency.

The upstream and downstream edges of the inner guide vane means 13 are located in both positions between imaginary circles a and b. A radial vector between circles a and b has a radial length of about 40% of a radial vector extending between the circle a and the circle c which extends along the outer edges of the outer guide vanes 12. The

upstream surfaces

124a, 124b, 124a of the outer vane means 12 extend between the circles c and d,

and a radial vector between circles c and d has a length of about 85% of the radial vector between the circles a and c in the position of FIG. 4. V

In a modified arrangement of the present invention shown in FIGS. 6 and 7, the sets of guide vanes 12 (120a, .1265, 123C) and 13 (121a, 121b, 1210) are disposed and operated as described with reference to FIGS. 4 and 5. A third stator member having a circular row of third guide vane means located between the guide vanes 13 and the vanes of rotor 11, is mounted for angular turning movement about the central axisofthe machine. In the position of FIG. 6, the third guide vane means 13th:, 139b, 130a are located behind the composite vane means formed by abutting

guide vanes

12, 13, and almost ineffective, while in the position of FIG. 7, the third guide vane means extend the composite guide vane means inwardly to further reduce the effective flow cross sections between the composite vanes and to further vary the angle of flow.

It will be understood that each of the elements described above, .or tWo or more together, may also find a useful application in other types of turbines differing from the types described above.

While the invention has been illustrated and described as embodied in a guide vane arrangement for thestator of a radial flow exhaust gas turbine, it is not intended to be limited to the details'shown, since ,various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 1

Without further analysis, the fore oing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for Various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a turbine, in combination, a first stator member including an annular row of first guide vane means; a second stator member including an annular row of second guide vane means; and means for moving one of said stator members between a first end position in which each second guide vane means abuts one first guide vane means and a second end position in which each second guide vane means laterally abuts another first guide vane means, said second guide vane means in both said first and second positions of said second stator member partly overlapping the respective first guide vane means and being partly located downstream of the same, each pair of first and second guide vane means abutting each other in said first end position forming a composite vane means having a first profile, and each pair of first and second guide vane means abutting each other in said second end position forming a composite vane means having a second different profile, said composite vane means forming free flow passages between each other in both said first and second positions so that the flow of fluid between said composite vane means is differently controlled in said first and second end positions due to said different first and second profiles.

2. In a turbine, in combination, a first member including an annular row of first guide vane means; a second member including an annular row of second guide vane means, each second guide vane means being at least partly located between two confronting lateral surfaces of two adjacent first guide vane means; and means for turning one of said members between a first end position in which each second guide vane means partly abuts said lateral surface of one of the respective two adjacent first guide vane means and a second end position in which each second guide vane means partly abuts said lateral surface of the other of the respective two adjacent first guide vane means, each pair of first and sec ond guide vane means abutting each other in said first end position forming a composite vane means having a first profile, and each pair of first and second guide vane means abutting each other in said second end position forming a composite vane means having a second profile, said composite vane means forming free flow passages between each other in both said first and second positions so that the flow of fluid between said composite vane means is differently controlled in said first and second end positions due to said difierent first and second profiles.

3. In a turbine, in combination, a first stator member including a circular row of first guide vane means; a second stator member including a circular row of second guide vane means concentric with said first row, said first and second guide vane means being staggered relative to each other, each first and second guide vane means being positioned to have an upstream surface and a downstream surface, each second guide vane means being located between confronting surfaces of two adjacent first guide vane means partly overlapping with the same and partly located downstream of the same, one of said stator members being turnable between a first end position in which an upstream surface portion of said upstream surface of each second guide vane means abuts a downstream surface portion of said downstream surface of one of the respective correlated two adjacent first guide vane means, and a second end position in which a downstream surface portion of said downstream surface of each second guide vane means abuts an upstream surface portion of said upstream surface of the respective correlated other adjacent first guide vane means, said abutting upstream and downstream surface portions being of matching shape and inclined at the same angle to radial vectors passing through the center of said circular rows, said first and second guide vane means abutting each other in said first end position forming first composite vane means, and said first and second vane means abutting each other in said second end position forming second composite vane means, said composite vane means forming free flow passages between each other in both said first and second positions, said first and second composite vane means having different profiles for diiferently controlling the flow of fluid in said flow passages between adjacent composite vane means; and operating means for turning said one stator member between said first and second end positions.

4. In a turbine, in combination, a first stator membcr including a circular row of uniformly spaced first guide vane means; a second stator member including a circular row of uniformly spaced second guide vane means concentric with said circular row of first guide vane means, said first and second guide vane means being staggered relative to each other, each first and second guide vane means being positioned to have an upstream surface and a downstream surface, each second guide vane means being located between confronting surfaces of two adjacent first guide vane means partly overlapping with the same and partly located downstream of the same, one of said stator members being turnable between a first end position in which said upstream surface of each second guide vane means abuts said downstream surface of one of the respective correlated two adjacent first guide vane means, and a second end position in which said downstream surface of each second guide vane means abuts said upstream surface of the respective correlated other adjacent first guide vane means, said first and second guide vane means abutting each other in said end position forming first composite vane means, and said first and second vane means abutting each other in said second end position forming second composite vane means, said first and second composite vane means having different profiles for differently controlling the flow of fluid in the passages between adjacent composite vane means, said first and second composite vane means defining different angles with axial planes passing through the center of said circular rows; and operating means for turning said one stator member between said first and second end positions.

5. In a turbine, in combination, a first stator member including a circular row of uniformly spaced first guide vane means; a second stator member including a circular row of uniformly spaced second guide vane means concentric with said circular row of first guide vane means, said first and second guide vane means being staggered relative to each other, each first and second guide vane means being positioned to have an upstream surface and a downstream surface, each second guide vane means being located between confronting surfaces of two adjacent first guide vane means partly overlapping with the same and partly located downstream of the same, one of said stator members being turnable between a first end position in which said upstream surface of each second guide vane means abuts said downstream surface of one of the respective correlated two adjacent first guide vane means, and a second end position in which said downstream surface of each second guide vane means abuts said upstream surface of the respective correlated other adjacent first guide vane means so that said upstream surface of said second guide vane means extends said upstream surface of said first guide vane means in downstream direction, said first and second guide vane means abutting of said first guide vane means and the downstream ends of said upstream surfaces of said second guidevane means;

and operating means for turning said one stator member between said first and second end positions. a

6. In a radial fiow gas turbine, in combination, a first stator member including a circular row of uniformly spaced first guide vane means; a second stator member including a circular row of uniformly spaced second guide vane means located inwardly in radial direction and concentric with said circular row of firstguide vane means, said first and second guide vane means being staggered relative to each other, each first and second guide vane means being positioned to have an upstream surface and a downstream surface, each second guide vane means being located between confronting surfaces of two adjacent first guide vane means partly overlapping with the same and partly located downstream of the same, one of said stator members being turnable between a first end position in which said upstream surface of each second guide vane means abuts said downstream surface of one of the respective correlated two adjacent first guide vane means, and a second end position in which said downstream surface of each second guide vane means abuts said upstream surface of the respective correlated other adjacent first guide vane means so that said upstream surface of said second guide vane means extends said upstream surface of said first guide vane means in downstream direction, said first and second guide vane means abutting each other in said first end position forming first composite vane means, and said first and second vane means abutting each other in said second end position forming second composite vane means, said first and second composite vane means having differentprofiles for differently controlling the flow of fluid in the passages between adjacent composite vane means, the narrowest flow cross sections of said passages being located in said first and second end positions between said downstream surfaces of said first guide vane means and the downstream ends of said upstream surfaces of said second guide vane means; and operating means for turning said one stator member between said first and second end positions.

7. In a turbine, in combination, a first stator member including a circular row of first guide vane means; a second stator member including a circular row of second guide vane means having a common center with said first row, said first and second guide vane means being staggered relative to each other, each first and second guide vane means being positioned to have an upstream surface and a downstream surface, each second guide vane means being partly located between confronting surfaces of two adjacent first guide vane means with an upstream part thereof overlapping downstream parts of said two first guide vane means and with a downstream part thereof located downstream of said two first guide vane means, said second stator member being turnable with said second guide vane means about said center between afirst end position in which said upstream surface of each second guide vane means partly abuts said downstream surface of one of the respective correlated two adjacent first guidevane means, and a' second end position in which said downstream surface of each second guide vane means partly abuts said upstream surface of the respective correlated other adjacent first guide vane means, said first and second guide vane means abutting each other in said first end position forming first composite vane means, and said first and second vane means abutting each other in said second end position forming second composite vane means, said composite vane means forming free fiow passages between each other in both said first andsecond positions, said first and second composite vane means having different profiles for differently controlling the flow of fluid in said flow passages between adjacent composite vane means; and operating means for turning said second stator member between said first and second endpositions. f

8. In a radial flow gas turbine, in combination, a first stator member including a circular row of uniformly spaced first guide vane means; a second stator member including a circular row of uniformly spaced second guide vane means located inwardly in radial direction and concentric with said circular row of first guide vane means, said first and second guide vane means being staggered relative to each other, each first and second guide vane means being positioned to have an upstream surface and a downstream surface, each second guide vane means being partly located between confronting surfaces of two adjacent first guide vane means with an upstream part thereof overlapping downstream parts of said two first guide vane means and with a downstream part thereof located downstream of said two first guide vane means, said second stator member being turnable with said second guide vane means about the center thereof between a first end position in which said upstream surface of each second guide vane means partly abuts said downstream surface of one of the respective correlated two adjacent first guide vane means, and a second end position in which said downstream surface of each second guide vane means partly abuts said upstream surface of the respective correlated other adjacent first guide vane means so that said upstream surface of said second guide vane means extends said upstream surface of said first guide vane means in downstream direction, said first and second guide vane means abutting each other in said first end position forming first composite vane'means, and said first and second vane means abutting each other in said second end position forming second composite vane means, said first and second composite vane means having different profiles for differently controlling the fiow of fluid in the passages between adjacent composite vane means, the narrowest flow cross sections of said passages being located in said first and second end positions between said downstream surfaces of said first guide vane means and the downstream ends of said upstream surfaces of said second guide vane means, said first and second composite vane means defining different angles with axial planes passing through the center of said circular rows; and operating means for turning said second stator member between said first and second end positions. 1 I

9. A radial flow gas turbine as set forth in claim 8 wherein said second guide vane means overlap said first guide vane means in said first end position to a lesser extent than in said second end position.

10. A radial flow gas turbine as set forth in claun 8 wherein said second member includes a projecting pin; and wherein said operating means includes a lever turnably mounted on said first member and having a forked end embracing said pin;

11. In a radial flow gas turbine, in combination, a first stator member including a circular row of uniformly spaced first guide vane means; a second stator member including a circular row of uniformly spaced second guide vane means located inwardly in radial direction and concentric with said circular row of first guide vane means, said first and second guide vane means being staggered relative to each other, each first and second guide vane means being positioned to have an upstream surface and a downstream surface, each second guide vane means being located between confronting surfaces of two adjacent first guide vane means partly overlapping with the same and partly located downstream of the same,

said second stator member being turnable with said second guide vane means about the center thereof between a first end position in which said upstream surface of each second guide vane means abuts said downstream surface of one of the respective correlated two adjacent first guide vane means, and a second end position in which said downstream surface of each second guide vane means abuts said upstream surface of the respective correlated other adjacent first guide vane means so that said upstream surface of said second guide vane means extends said upstream surface of said first guide vane means in downstream direction, said first and second guide vane means abutting each other in said first end position forming first composite vane means, and said first and second vane means abutting each other in said second end position forming second composite vane means, said first and second composite vane means having difierent profiles for difierently controlling the flow of fluid in the passages between adjacent composite vane means, the narrowest flow cross sections of said passages being located in said first and second end positions between said downstream surfaces of said first guide vane means and the downstream ends of said upstream surfaces of said second guide vane means, said first and second composite vane means defining difierent angles with axial planes passing through the center of said circular rows; 2. third stator member located inwardly of said second stator member and including a circular row of third guide vane means, said third stator member being turnable between a position in which said third guide vane means abut said second guide vane means when the same form part of said first composite vane means and another position in which said third guide vane means abut said second guide vane means when the same form part of said second composite vane means, said third guide vane means extending said second composite vane means inwardly in said other position of said third stator member; and operating means for turning said second stator member between said first and second end positions, and for turning said third stator member between said positions thereof.

12. In a turbine, in combination, a first stator member including a circular row of first guide vane means, each first guide vane means having an upstream edge, a downstream edge, and upstream and downstream lateral surfaces between said edges; a second stator member including a circular row of second guide vane means having the same number as first guide vane means, each second guide vane means having an upstream edge, a downstream edge, and upstream and downstream lateral surfaces between said edges thereof, each second guide vane means being partly located between confronting lateral surfaces of a pair of adjacent first guide vane means and having said upstream edge thereof located upstream of said downstream edges of said adjacent first guide vane means, one of said stator members being turnable relative to the other stator member between a first position in which an upstream portion of the upstream lateral surface or each first guide vane means abuts a downstream portion of the downstream lateral surface of the respective adjacent second guide vane means, and a second position in which an upstream portion of the downstream lateral surface of each first guide vane means abuts a downstream portion of the upstream lateral surface of the respective other adjacent second guide vane means, said abutting surface portions having matching shapes and inclinations so that in said first position first composite vane means having a first profile and in said second position second composite vane means having a second different profile are formed by first and second guide vane means, said composite vane means forming free flow passages between each other in both said first and second positions.

13. A turbine as set forth in claim 12 wherein the narrowest cross section of the flow passage between adjacent composite vane means is located between the downstream lateral surface of the first guide vane means of each composite vane means and the downstream edge of said second guide vane means of an adjacent composite vane means.

14. A turbine as set forth in claim 12 and including a third stator member including a circular row of third guide vane means, each third guide vane means having an upstream edge located upstream of the downstream edges of a pair of adjacent second guide vane means, a downstream edge located downstream of the downstream edges of the adjacent second guide vane means, and upstream and downstream lateral surfaces matching the shapes and inclinations of the confronting downstream and upstream surface portions of adjacent second guide vane means, said third stator member being turnable between a first position in which said third guide vane means respectively abut one adjacent second guide vane means and form a composite vane means with the same and with the respective first guide vane means, and a second position in which said third guide vane means respectively abut the other adjacent second guide vane means and form a composite vane means with the same and with the respective first guide vane means.

References Qited by the Examiner UNITED STATES PATENTS 2,314,572 3/43 Chitz 253-78 2,351,516 6/44 Iandasek 253-78 2,861,774 11/58 Buchi 25352 FOREIGN PATENTS 624,185 7/61 Canada.

91,931 5/97 Germany.

SAMUEL LEVINE, Primary Examiner.

WALTER BERLOWITZ, Examiner.