US2763462A - Turbine casing construction - Google Patents

Description

Sept., 18, 1956 c J. McDowALL ETAL 2,763,462

TURBINE: CASING CONSTRUCTION 5 Sheets-Sheet l Filed Jan. 11, 1950 Sepi- 3 1955 c. J. McDowALL x-:TAL 2,763,462

TURBINE CASING CONSTRUCTION y 5 Sheets-Sheet 2 Filed Jan. ll, 1950 www( ,mf ff f i I I I l I l I 3 Wi@ ww l JW Y m a@ m B m n K A -IHN M, MM. Q

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TURBINE CASING CONSTRUCTION Filed Jan. l1

5 Sheets-Sheet 3 Sept. 18, 1,956 c. J. McDowALl. ET AL 2,763,462

TURBINE CSING CONSTRUCTION 5 Sheets-Sheet 4 Filed Jan.. l1, 1950 mwN Sem 38, 1956 c. J. MoDowALl. ETAL 2,763,462

TURBINE CASING CONSTRUCTION 5 Sheets-Sheet 5 Filed Jan. ll ,A1950 Bg @der Wa/View? ilnited States Patent O TURBINE CASING CONSTRUCTION Charles J. McDowall and Oscar V. Montieth, Indianapolis, Ind., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application January 11, 1950, Serial No. 138,026

8 Claims. (Cl. 253-78) This invention relates to combustion engines and more patricularly to axial ow .gas turbine power plants.

This invention relates to an axial ilow compressor turbine power unit, which provides a propeller drive and a supplemental jet power source. The compressor turbine unit is mounted coaxially on the same shatt with the -compressor at the forward end. The propeller is connected to the forward end of the compressor. The air passes over suitable fairing and enters the axial llow compressor where it is compressed. Then the main portion of the air enters the combustion chamber or burner and the remainder passes around the combustion chamoer to cool it. The combustion chamber is expansible and is mounted o-n fixed supports at the forward end and in a splined support to allow axial sliding due to expansion at the rear end. The complete compressor turbine power unit is supported from a torque ring which is centrally located. A cylindrical shell is secured to the torque ring and extends rearwardly surrounding the turbine unit, and provides an outboard support for the rear bearing. The stator turbine blading comprises a series of `segments with interengaging tongues which interiit in a series of annular rings. are secured together to provide the exterior conical casing for the turbine. rihis casing is supported by a splined joint with the cylindrical shell, The rotor wheels are secured to the main shaft 'by suitable splines, and are centered about the shaft by annular wedge-shaped elements engaging each side of the wheels. The wheels supp-ort suitable turbine rotor blades which rotate between the stator blades.

The primary object of this invention is to provide a supporting structure for a compressor turbine power unit with provision for expansion in the power unit.

Another object of the invention is to provide in a compressor turbine power unit a burner or combustion chamber having a fixed support at one end and an axially sliding support at the other end, in order to provide for relative expansion ybetween the combustion chamber and the other portions of the power plant.

Another object of the invention is to provide in a turbine used in an internal combustion engine power plant a supporting shell `surrounding the turbine and connected to the turbine by means of a splined joint, and bearing support means secured to the turbine casing to support the rear end of the main shaft and to provide relative expansion of the -shell and casing.

Another object of the invention is to provide in a rotary machine a conical housing formed of a plurality of stepped ring sections secured together and having a conical lining or fairing inside formed of a plurality of annular segment sections secured to the inside of said rings.

Another object of the invention is to provide in a rotary machine a .generally conical housing formed of a plurality of rings of increasing diameter secured together and having axially directed internal flange lips to support an inner fairing or lining consisting of a plurality The annular rings 'ice of annular segmental members having axially directed annular hooks engaging said lips to support and position said fairing members within said casing.

These and other objects of the invention will be more apparent from the following description and drawings of a preferred embodiment of the invention.

In the drawings,

Figure 1 is an elevation View with parts in section of the compressor turbine power unit.

vFigure 2 is a fragmentary enlarged elevation with parts in section of the combustion chamber.

AFigure 3 is a fragmentary enlarged elevation with parts in section of the turbine unit and blading.

Figure 4 is a fragmentary enlarged elevation with parts in section of the turbine shaft and turbine wheel con nection.

Figure 5 is a section of Figure l on the line 5 5 with parts broken away.

The compressor turbine unit illustrated in the drawing is built around a iloating shaft 10 which is connected at its forward end to a compressor shaft 12. The compressor shaft 12 is rotatably supported by bearing 14 mounted in the forward end 15 of the power plant housing 16. The rear portion of the shaft 1b just forward of the turbine is supported and rotatably secured to shaft 230 by a spl-ined connection. The end of shaft 23u adjacent the splined connection is supported by a bearing 18 in the rear portion 19 of housing 16. A propeller drive shaft (not shown) may be connected to the forward end of the compressor assembly. The compressor assembly consists of a rear compressor shaft 12 and a series of wheels 22 which support suitable rotatable compressor blading 24 and are held together by the tie rod 20. The air enters through a suitable faired compressor entrance (not shown) and is compressed by the com pressor rotary blades 24 and stator blades 26 or diffuser vanes mounted in the compressor housing 28. A plurality of combustion chambers or burners 30 are arranged `around shaft 10 between the compressor and turbine. Each burner 3i) has an enlarging passage 32 connecting `a sector of the outlet of the compressor to the central cylindrical portion 33 of the burner 3ft. The liner 34 has a central cylindrical portion spaced from the burner 30. The forward end 36 of the liner has a reduced diameter and is spaced from the walls of the passage 32 so that a portion of the air flows between the liner 34 and the burner housing 36 to cool the liner.

An air baille or llame holder 38 is positioned at the forward end of the liner directly in front of the fuel nozzle 40. The liner 34 is supported by suitable spaced supports 42 to the burner 30. The forward passage portion 32 of the burner 30 may be formed integral with or secured to the casing 16. To the rear of the supports 42 the burner housing 30 has an enclosure 44 formed of `a pair of spaced overlapping wall portions which provides protection for a corrugated metal expansion diaphragm 46 to seal the joint.- A central portion 48 of the liner 34 has a sliding joint with the forward end and the rear end 49 of the liner.

The central housing 16 has a central sleeve 5t) and an external sleeve 52 extending from the forward bearing support 15 to rear bearing support 19. An annular plate 54 surrounds the external sleeve 52 of the housing 16 and is rotatably xed by interengaging splines 5S secured to the external sleeve 52, The plate 54 is rotatably xed at its outer perimeter to a ring 53 by intel-engaging splines 56 on the outer edge of the plate and the inner edge of the ring. The ring S3 is bolted to the torque ring 58. The splines allow axial movement of the annular plate with respect to the ring 53 and the frame 16. The torque ring 58 which has a box section is braced by a plurality of diagonal struts 60 suitably connected to the ring 58 at spaced intervals and secured to the sleeve 52 by brackets 62. Radial bracing struts 64.are secured to strut 60 and the sleeve 52. The plate 54 has an annularly disposed series of sector shapedapertures 57 for each one of the combustion chambers 30. As shown on the leftfside 'of Figure and Figure 2, the outer shell 33 of the burner 30 has a flange suitably secured to the sector plate 59. The plate 59 has a circular aperture for the burner and is secured at its inner and Vouter edges by suitable means such as bolts 68 to the annular plate 54. The sides of the sector plates 59 seat on the annular plate 54 between the apertures 57 and are clamped in position by clamping bars 61. As explained above the rear end of the burner 30 is attached to the forward side of the plate 54. The annular series of burner liner portions 49 are surrounded by an annular wall 72. This wall 72 is secured at its forward end tothe rear side of plate 54 by bolts 68 and ts over the outer edge of the turbine inlet 92. An inner annular' wall 74 is positioned between the burners and the main shaft. This wall 74 is secured at the forward end to the inner edge of plate 54 by bolts and engages the inner edge of the turbine linlet 92. The inner wall 74 and outer wall 72 are concentric with the shaft and provide an annular space for the series of rear liner sections 49. A plurality of ducts 76 connects the walls 72 and 74 to provide for the passage of cooling air from the space between the shaft housing and the inner wall 74 to the space between outer wall 72 and cylindrical housing 88.

The turbine stator housing 78 is supported at the forward end by the outer portion of an annular plate 80 which is piloted on or slidably supported on the outer cylindrical portion of the housing at the rear bearing support 19. The rear end of the housing 78 has an annular splined flange 84 which is slidably supported in an annular flange 86 secured to a cylindrical shell 88 supported on the torque ring 58. The cylindrical shell 88 has an outlet conduit 90 for the cooling air. The stator housing which is supported at its forward end on the annular plate 80 consists of a plurality of annular rings bolted together. The plate 80 has near its permimeter an aperture having the shape of an annular segment for each combustion chamber. Each of these apertures is bounded by a wide ilange 92 to support the end of the burner. Referring to Figure 3 for clarity, the iirst external ring 94 of the casing 78 is connected to the flange 92 of the plate 80 and terminates in a radial flange 96 and axial flange 98. The integral assembly of the plate 80, the flange 92 and ring 94 may be formed by welding the parts together. The first row of stator blading 102 consists of a plurality vof segments having an external rim 104 and an internal rim 106 which fit within the flange 92. The blade segments 102 are circumferentially positioned by threaded pins 108. The second ring 110 has a recess 112 which seats on the end of axial flange 98 and a radial flange 114 which engages in face to face relation the radial llange 96 of the first ring 94. An annular series of bolts secure flanges 96 and 114 together. The annular ring 110 is stepped to provide a small cylindn'cal portion adjacent flange 114 and a large cylindrical portion. The ring 110 has adjacent its small edge an offset axial flange or lip 116 and adjacent the center an offset axial llange or lip 118, and adjacent the large edge an ollset axial flange or lip 120. The interior surface of the housing is formed with a plurality of rows of segments to form Ia generally smooth conical shape. The first row of the interior surface of the housing 78 is formed by a plurality of segments 122 which have adjacent each edge axial flanges or hooks 124 and 125 which fit over the lips 116 and 118 respectively of the ring 110. A threaded pin 126 prevents rotary displacement of the segments. A second row of stator blading 128 is formed in segments and is secured to outer ring segments 130 and inner ring segments 132. The outer ring segments have displaced axial flanges or hooks 134 and 13S. The hook 134 on the smaller side extends over the hook V125 of the preceding fairing segment 122 and the other hook 135 engages the lip 120 at the large end of the ring 110. A pin 136 prevents circumferential displacement of the stator blade segments 128. At the large end of the ring a flange 138 having an axial offset portion and main radial portion extending outwardly at the end of the axial portion is provided in order to secure the ring 110 to the next ring 140.

The second ring 140 has a similar stepped construction to provide a samll cylindrical portion and a large cylindrical portion. At the edge of the sm-all cylindrical portion a flange 142 having a radial portion and an axial portion extending from the inner edge of the radial portion interengages the axial and radial portions of flange 138 to position the ring 140 with respect to the ring 110. The flanges are secured together by means of bolts 144. The ring 14d) has an annular axial flange or lip 146 at the center and a similar lip 148 at the large edge. Fairing segments 150 which are employed to present a smooth conical interior surface, have axial flange hooks 152 and 154. The hook 152 at the smaller side of the ring segment 150 extends over the hook of the previous stator blade ring 130. These two anges seat against the lip 120 of ring 110. At the other side of fairing segment 150 the hook 154 hooks over the llip 146. The pins 156 prevent circumferential displacement between the ring and the fairing segments 159. The third row of axial stator blades 158 has a similar outer ring 160 and an inner ring 162. The outer ring has axially disposed flange hooks 164 and 166 which fit over the hook 154 of the preceding fairing segment and over the lip 148 of the ring 140 respectively. A threaded pin 167 prevents circumferential movement of blade segment 160. The ring 140 has at its larger edge a flange 168 having an axially extending portion radially outward from the lip 148 and a radially extending portion at the end of the axial portion. The flange 168 is secured by bolts 174 to the ring 178 which has a flange 172 having a complementary radial portion and axial portion extending from the base of the yradial portion. The ring has a stepped construction with a smaller and a larger cylindrical portion. Between these two portions an axially extending lip 176 is provided to support the fairing members and blade segments. Fairing members 178 of segmental form with conical interior surfaces have axially directed flange hooks 180 and 182 at opposite sides. The hook 189 overlies ythe hook 166 on the outer ring 160. The axial portion of flange 172 fits over these flanges. The hook 182 hooks over the lip 176 to support the other side of the various segments 178. The segments 178 are held in Vcircumferential position by the threaded pins 184.

The last row of stator blades 186 is secured between an inner ring 188 and an outer ring 190. The outer ring 190 has an axially directed flange hook 192 at one end overlying the llange 182. At the other side of the ring 190 the flange 194 extends outwardly from the ring and fits in a recess in the ring member 196. It should be noted that on each of the fairing ring segments and outer blade ring segments the ilange hooks on each side were directed in the same direction, toward the small end of the turbine housing 78. The ring 170 has the flange 198 having an axial portion and a radial portion at the end of the axial portion. The axial portion secures the flange 194 in th'e recess195 and the axial and radial portionsinterfit with axial and radial portions of flange 280 on ring 196. Boltsf202- hold these flanges together. A pin v204 positions the last row of blades 186 circumferentially. The ring 196 has a flange 206 which -is suitably secured and nterlocked by means of axial and radial portions to flange 208 on the supporting ring 210. The supporting ring 210 may bemade integral with the splined flange 84which slidably supports the assembly fromfthe cylindrical shell 88. At the rear of the supporting ring 210 a jet fairing ring `or tail cone 212 is secured. An inlet conduit 214 is connected to the jet fairing ring to bring cooling air to the interior of the double wall flow vanes 216.

A radial bearing support strut 218 is secured to the supporting ring 210 at the outer end and `at the inner end to the bearing support member 220. A diagonal strut 222 extends from the outer end of the radial strut 218 to the gusset 224. The gusset 224 is connected by an inner diagonal strut 226 to the bearing support 220. The gusset 224 supports the interior ring or wall 228 of the jet passage. As shown in Figure 4 the turbine shaft 230 extends from the central bearing 18 to the rear bearing 232 and is mounted in the bearing support 220. The shaft 230 has a splined section 234 for each rotary blade wheel. The rotary blade wheels 236, 238, 240 and 242 each support a plurality of rotor blades secured to the periphery of the wheel. At the rear end of the turbine shaft 230 there is an integral annular abutment 244 and a two piece annular ring 246 which have tapered surfaces engaging the central aperture of wheel 242 to center the wheel on the shaft. Similarly wheels 240 and 238 are centered on the shaft by engaging the wedge or conical surfaces on the two piece annular spacing members 246, 248 and 250. As shown in Figure l, a similar annular wedge 252 which is secured by the seal member 253 threaded on the shaft 230 engages the forward side of wheel 236 to center this wheel and tighten all the wheels and their annular wedges against the integral rear abutment 244. Referring to Figure 3 the wheel 236 extends between stator blades 102 and 128 to support rotor blades 254. A ring baffle 256 is secured to wheels 236 and 238. The ring baie 256 and the flanges on the ring 132 limit the flow around the stator blades 128. The wheels 238 and 240 support rotor blades 258 and 264 and baille ring 260 which cooperates with flanges on the rim 162 to limit the by-pass ow around the stator blades 158. In the same manner wheels 2410 and 242 support the blades 264 and 265 and ring baflie 266 which in connection with the flanges on the rim 188 reduces the by-pass iiow around the stator blades 186.

Just to the rear of the last wheel 242 an annular panel 26S closes the space between the bearing support 220 and the inner wall 228 of the jet passage. There are spaces between the strut anchorages in member 220 through which air coming from inlet 214 and passing through vanes 216 to the other side of partition 268 is sucked out between partition 268 and wheel 242 into the flow of gas in the jet passage. This air flow cools the rear bearing 232. The bearing support 220 also supports an oil pump housing and sump 270. The rear end of the oil sump 270 is supported by a radial strut 272 attached to the gusset 224. A gear 274 attached to the end of shaft 230 drives the return oil pump 276 which pumps oil into the space between the sleeve 278 and the conduit 280. The oil flows from a main oil pump (not shown) through the hollow tie bolt 20 and compressor shaft 12 to lubricate forward bearing 14 and through conduit 280 in floating shaft to lubricate central bearing 18 and through conduit 280 in shaft 230 to auxiliary passage 281 Where the oil is sprayed on bearing 232. The conduit 280 acts as a tie bolt to hold shaft 10 and shaft 230 together. At the forward side of bearing 232 a seal 282 prevents the flow of oil into the turbine space. The oil lubricates bearing 232 and drops into sump 270 where pump 276 returns the oil through the space between sleeve 278 and conduit 280 to the sump in the base of bearing support 19. The bearing support 19 has a portion providing a sump for oil pump 284 which is driven by gear 286 on floating shaft 10. The pump 284 lifts the oil from the sump in support 19 and forces the oil through passage 288 and into pasage 291 in the forward end of the housing 52. The oil from bearing 14 flows into the sump 290 in the lower portion of the bearing support housing 16. A gear 292 on shaft 10 drives a gear pump 294 which returns 6 the oil from sump 290 to the main oil 'tank through passage 291.

In order to reduce the end thrust on the compressorturbine rotor assembly conduits 300 are provided as shown in Figure l to connect the air space on the rear side of the compressor wheel with the air space on the forward side of the turbine wheel in order to balance the gas forces. The first turbine wheel 236 as shown in Figure 3 has an axially extending flange 302 which extends into a labyrinth seal 304. Cooling air is also circulated through the center of the housing and -around the sleeve 50 by centrifugal impeller blades 306 mounted on the shaft 230 close to the forward face of turbine wheel 236. The im` peller blades 306 draw air from the center region between sleeve 50 and housing 52 past tins 305 and about the bearing 18 and force the air out through the passage 308 and apertures in partition 309 and through the hollow ducts 76 between the burners 30 to the outlet 90 in the cylindrical support 88. A flange 312 is secured to the cooling impeller immediately above the passage 308 and interts with the annular labyrinth seal element 314 on the fan housing to prevent leakage between the cooling air passage and the equalizer passage.

The compressor turbine power unit propels the ship by means of a propeller driven through the compressor rotor assembly mounted on the forward end of the main shaft and of the jet reaction. The air enters at the forward end of the power unit and is compressed by the compressor unit consisting of rotor blades 24 and stator blades 26, and enters the burners 30 Where fuel is supplied by the nozzle 40. The hot gases are then produced in the combustion chamber and rapidly flow through the combustion chamber to the turbine. In the turbine the gases expand and drive the turbine in the conventional way. Due to the fact that high combustion heats are localized in the combustion chambers and adjacent the turbine blading, there is liable to be a large temperature dilerence between various parts of the power plant and thus large di'erences in the expansion of various parts of the machine. In order to permit this expansion without destruction or distortion of the power plant the important elements of the unit are mounted to allow for expansion between them. The burners are fixed at their forward end to the frame 16 but are fixed at their rear end in an annular plate which is mounted for sliding movement to allow for expansion. An expansion joint is also provided in each burner 30 to provide for the differential expansion between the burners and the frame between the forward end of the housing 52 and the annular thrust plate 54. The aft portion of the turbine assembly is supported by the shell 88 by means of the splined connection 84-86 in order to allow for differential expansion between the support means andthe turbine assembly. Thus the combustion chamber and the turbine assembly can expand relative to their supports without deforming or straining any portion of the power plant. The turbine wheels are secured on the turbine shaft 230 by means of interengaging splines 234 and are centered with respect to the shaft by means of the annular two-piece rings which have wedge shaped portions at each side so that the turbine wheels may be wedged into concentric relation with the shaft.

The turbine stator section 78 is formed of a plurality of stepped annular rings which support an internal fairing or lining. A portion of this internal fairing is formed by the exteral rings of the stator blades. Each of the casing rings 110, 140 and 170 are stepped to provide a small and a large cylindrical section. The rst ring has three axially directed flange lips 116, 118 and 120 which provide support for the hooks at each side of fairing segments 122 and fairing and blade support segments 130. The second ring has two lips 146 and 148. The fairing segments have hooks which engage the last lip on the first ring 110 and a lip on the second ring.

The blade ring segment 160 has hooks engaging both lips of the second ring. The third ring 170` has one central Alip 176. The fairing segments 178 have hooks engaging the -end lip of ring 1'40 and the lip 4of ring 170. The blade ring segments 190 have hooks engaging the lip on ring 170 -and final spacer ring 196. This construction provides ka simple arrangement of parts to provide a structure which may be easily assembled and disassembled for repair from a plurality of simple replaceable parts.

Certain features of our invention disclosed but not claimed` herein are claimed in our divisional application Serial No. 572,861, filed March 21, 1956, for Gas Turbine Power Plant.

It will be appreciated that the above described embodiment of the invention fis illustrative of the various features of the invention and that many modifications of the invention may be made within the scope of the appended claims.

We claim:

l. A stator structure for a gas turbine or the like comprising a casing, axially extending lips on the casing defining axially extending recesses between the lips and inner surface portions of the casing radially spaced from the lips, segmented fairing rings mounted in the casing having flanges terminating in axially extending parts, the said parts of adjacent edges of two adjacent fairing rings being received in a said recess, and locating means extending from the casing into each segment of the fairing rings adapted vtorestrain the segments against axial and circumferential movement.

2. A structure as defined in claim 1 in which the locat ing means extend through the casing and are removable from the exterior of thecasing.

3. AV stator structure for a gas turbine or the like comprising a plurality of casing rings, means for fixing the casing rings together at the ends thereof' to constitute a casing, axially extending lips on the casing rings defining axially extending recesses between the lips and innerl surface portions of a casing ring radially spaced from the lips, fairing rings mounted in the casing having flanges terminating in axially extending parts, the said parts of adjacent edges of two adjacent fair-ing rings being received in a said recess, and locating means extending from the casing into the fairing rings adapted 'to restrain the rings against axial and circumferential movement.

4. A structure as recited in claim 3 in which the casing rings are of .progressively increasing diameter toward one end of the casing and the fairing rings are 8 movable` through the casing rings `for removal from the said end of the casing.

5. A stator 'structure for a gas turbine or the like comprising a plurality of casing rings, means for fixing the casing'rings 'together at the ends thereof to Vconstitute a casing, axially extending lips on `the casing rings defining axial-ly extending recesses between the lips and inner surface portions of a casing ring radially spaced from the lips, segmented fairing rings mounted in the casing having fianges terminating in axially extending parts, the said parts of adjacent edges of two adjacent fairing rings being received in a said recess, and locating means extending from `the casing into each segment of the fairing rings adapted to restrain the segments against axial and circumferential movement.

6. A structure as defined in claim 5 in which each casing ring has two lips and mounts two rows of fairing rings.

7. A stator structure for a gas turbine or the like comprising a plurality of casing rings, means for fixing lthe lcasing rings together at the ends thereof to constitute a casing, axially extending lips on the casing rings defining axially extending recesses between the lips and inner surface portions of a casing ring radially spaced from the lips, and segmented fairing rings mounted in the casing having flanges terminating in axially extending parts, the said parts of adjacent edges of two adjacent fairing rings being received in a said recess.

8. A stator structure for a gas turbine or the like comprising a casing, axially extending lips on the casing defining axially extending recesses between the lips and inner surface portions of the casing radially spaced from the lips, and fairing rings mounted in the casing having flanges terminating in axially extending parts, the said parts of adjacent edges of two adjacent fairing rings being received in a said recess.

Y References Cited in the file of this patent UNITED STATES PATENTS 2,282,894 Sheldon May 12, 1942 2,432,359 Streid Dec. 9, 1947 2,458,148 Cronstedt I an. 4, 1949 2,461,242 Soderberg Feb. 8, 1949 2,472,062 Boestad June 7, 1949 2,479,573 Howard Aug. 23, 1949 2,488,867 Judson Nov. 22, 1949 2,488,875 Morley Nov. 22, 1949 2,494,821 Lombard Jan. 17, 1950 2,529,958 Owner Nov. 14, 1950 2,584,899 McLeod Feb. 5, 1952

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