US2233369A

US2233369A - Turbine blading

Info

Publication number: US2233369A
Application number: US257927A
Authority: US
Inventors: James L Ray
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1939-02-23
Filing date: 1939-02-23
Publication date: 1941-02-25
Anticipated expiration: 1958-02-25

Description

Feb. 25, 1941.' J Y 2,233,369

TURBINE BLADING Filed Feb. 23. 1959 Patented Feb. 25, 1941 PATENT OFFICE 2.233.369 'rnnnmn nmnnvo James L. Ray, Wauwatosa, Wis asslgnor to Allis- Chalmers Manufacturing Company, Milwaukee,

Wis., a corporation of Delaware 16 Claims.

This invention relates to turbine blading and more particularly to the construction and the manner of mounting the impulse blades of elastic fluid turbines.

The design of efficient impulse blading for high pressure, high temperature turbines of the superimposed or topping unit type necessitates in most instances the use of opposed concave convex fluid passage defining surfacesdisposed in nested or in partially nested relationship to form a circumferential blade row. The known manner of construction a circumferential blade row in which spaced concave convex fluid passage deflning surfaces are disposed in nested or in partially nested relationship embodies the use of a circumferential extending blade retaining groove and blades each having a root portion and a body portion including oppositely disposed concave convex surfaces. The retaining groove or grooves,-depending upon the number on circumferential blade rows employed. are each enlarged usually at only one point topermit the insertion of the blade root into the groove. The

blades are inserted one at a time and are moved circumferentially of the groove from the point of insertion and into spaced nested relationship until the groove is completely filled. The last blade to be inserted is secured in place by suitable wedging and locking members.

Experience in designing turbines to operate with steam at extreme high pressures and temperatures and at high rotative speeds shows that the intermittent application of the driving fluid in partial admission wheels; which produces forces that may amount to many hundreds of pounds per blade, necessitates the use of blades of relatively great width for safe operation, when blades of great width are employed under conditions of high relative speed and high temperature, the use of a circumferential retaining groove becomes impractical because of the great width of the supporting rims at the sides of the blades and also because of the great difllculty of providing a suitable closing or locking device for holding the last blade in place. There is no known manner of inserting and securing the last blade in a circumferential groove in which blades are spaced to provide highly efficient fluid passages under conditions of maximum capacity and maximum temperature without materially inand replacement of a defective blade is extreme- Application February 23, leis, Serial No. 257,927

ly expensive as all of the blades disposed between the defective blade and the enlarged portion of the retaining groove must first be removed. Moreover, the enlargement of a circumferem' tially extending blade retaining groove, to per- 5 mit the insertion of the blades, greatly weakens the portions of the generally horizontal blade retaining surfaces in the region of the enlargement, and the bending moments set up by the intermittent application of the driving fluid renl0 der the obtainment of a stable structure highly impractical. Furthermore, the formation of a sealed fluid confining passage necessitates the use of an integral shroud structure and the welding together of the abutting edges of adjacent shrouds which in turn hinders the ready removal and replacement of defective blades. In addition, the dimensions of the fluid confining passages will vary with the blade pitch and degree of accuracy with which the blades are assembled. 20

Therefore, it is an object'of this invention to provide an improved and novel impulse blade construction for elastic fluid turbines.

Another object of this invention is to provide a novel and improved impulse blade construction 25 presenting a fluid confining passage of fixed dimensions.

' Another object of this invention is to provide an improved and novel impulse blade construction presenting a sealed fluid confining passage. 30

Another object of this invention is to provide a novel and improved impulse blade construction embodying spaced concave convex passage defining surfaces disposed in nested or in partially nested relationship. 35

Still another object of,this invention is to provide a novel and im'proved impulse blade assembly permitting the separate insertion and removal of any individual blade from a circumferential blade row in which spaced concave con- 0 vex fluid passage defining surfaces are disposed in nested relationship.

The invention accordingly consists of the various features of construction, combination of elements, and arrangement of parts, as more fully 4 set forth in the appended claims and in the 'detailed description, in which: Y

Fig. 1 is a perspective view of two blade forming structures embodying the invention disposed in their proper cooperative relationship; 50

Fig. 2 is a partial sectional view illustrating a turbine spindleembodying the invention. and vthe coasting portion of the turbine casing;

Fig. 3 is anelevational view of the right hand side of the smaller blade structure shown in 5 Fig. 2 with the adjacent portion of the spindle shown in section:

Fig. 4 is an elevational view of the left hand side of the smaller blade structure shown in 5 Fig. 2;. Fig. 5 is a sectional view of a blade forming structure taken on line V-V-of Fig. 2;

Fig. 6 is a top plan view of the smaller blade structure shown in Fig. 2; and Fig. 7 'is a sectional view taken on line VII-VII of Fig. 2.

The blade construction illustrated in the drawing comprises adjoining blade forming, structures each having a'root portion i, and a body portion 2, which portions together constitute the supporting portion of a blade forming structure, and means designated generally by the numeral 3 extending from the body portion 2 and defining a fluidconfl'ning passage or channel 4. The passage defining means 3 includes a first member t having a'ooncave side surface '8 and a second member d s'pahed from said first member and having aconvex side surface 9 disposed in partially nested relationship with respect to the concave surface '6. The remaining side surfaces of the first member 6 include oppositely disposed plane surfaces ii, each of which is approximately tangential with respect to the adjacent edge of the concave surface 1, and a third plane surface i2 oppositely disposed with respect to the concave surface i. The second member 8 also has a plane side surface l3 oppositely disposed with respect to the convex surface 9 and with respect to the plane surface I2 of the first member 6. The first member 8 has a top portion i4 extending beyond each of said oppositely disposed side surfaces il and'in overlying relationship with respect to the body portion 2. A sealing member i6 conforming with the configuration of the fluid passage t when viewed in plan is disposed between the first and second members 6 and 8 and coacts with said firstand second members and with the top portion l4, and defines with said first and second members and body portion a as sealed fluid confining passage. The member it may be secured in place in any desired manner such as by welding.

The oppositely disposed plane side surfaces H of the first member 6, in addition to being 942- 5o proximately tangential with respect to the adjacent edge of the concave side surface i, are substantially tangential with respect to the convex surface s at the adjacent edge of the fluid passage or channel '6 of the next adjacent blade 55 structure. The body portion 2 and the top portion It, including the sealing member 88, have oppositely disposed side surfaces it. and i9, respectively, disposed in the plane of the similarly disposed plane side surfaces 82 and it of the first so and second members, respectively. The oppositely disposed plane side surfaces l2 and i3 may lie in planes having a common axis coincident with the axis of the turbine spindle on which the blades are adapted tobe mounted. The abut- 65 ting surfaces of adjacent blade forming structures are adapted for sliding engagement and dimensioned for coincident contact.

The top surface 9 of the body portion 2, which extends beyond the plane side surfaces ii, forms 70 an approximate continuation of the surface defining the bottom of the fluid passage or channel 4 of the next adjacent blade structure. The body portion 2 is provided with a projection extendin laterally with respect to the blade row and pre- 75 senting a plane sealing surface 20, as shown in Figs. 1, 2, and 6. The under surface 2| of the top portion forms a continuation of the under surface of the sealing member l6 of the next adjacent blade structure. The construction is such that when the blade forming structures are as- 5 sembled in abutting relationship to form a circumferential blade row, as best shown in Fig; l, the plane side surfaces l2, IT, and iii of one blade forming structure are in substantial coincidence with the plane side surfaces i3, ii, and 10 id of the next adjacent blade forming structure, the plane side surfaces Ii on one blade member form with the convex side surface 9 on the next adjacent blade a continuous fluid directing surface. and the top surface iii of the body por 15 tion 2 and the under surface 2| of the top portion it and of the sealing member 16 form with the similar surfaces-of the next adjacentblade forming structure continuous fluid confining and directing surfaces. 20

Stated differently, the illustrated blade forming structures each has oppositely disposed side surfaces arranged for silding engagement and coincident con-tact with the like surfaces of adjacent structures and each structure comprises 25 a supporting portionhavlng oppositely disposed sides and a complementary blade forming member extending from said supporting portion adjacent each of said sides and said members each including a side surface defining the major por- 30 tion of the said oppositely disposed surfaces on said structure. In this connection it should be noted that each structure includes two blade forming members each of which is the complement of that portion of a blade defined by the other of the said two members and that each member on one structure is also the complement of that portion of a blade defined by the adjacent member on an adjoining structure.

In order to secure the best flow eiiiciency, the 40 width of the fluid confining passage 4, as best shown in Figs. 6 and 7, gradually decreases toward the outlet end while the height of the passage, as shown in Fig. 2, increases toward the outlet'end. The central portions of the opposed r, concave convex passage defining surfaces I and 9 are, best shown in Figs. 4 and 5, substantially parallel to the plane side surfaces i2 and i3, respectively. The fluid confining passage or channel 4 may be machined in a generally rectangular metal block of suitable dimensions by means of an ordinary hollow, cylindrical milling cutter. The hollow cylindrical cutter is mounted for exact verticalmovement, and the block is rigidly held by any suitable means in a position slightly inclined with respect to the vertical axis of the cylindrical cutter and so that the axis of the cutter is in coincidence with the center of ourvature 22, as seen in Figs. 6 and 7. The convex side surface 9 can then be machined by a single on cutting operation. The block is then tilted in the opposite direction. and shifted with respect to the axis of the cylindrical cutter so that the axis of the cutter is in coincidence with the center of curvature 23, shown in Figs. 6 and 7. The concave surface 1 can then be machined by a single cutting operation. Consequently, only two machining operations are necessary to form the fluid passage or channel 4. The same result can obviously be accomplished by securing the block in an exact vertical position and by tilting and shifting the hollow cylindrical cutter in thesame respects as specified in the example in which the block was tilted and shifted and the cutter remained in an exact vertical position. The plane -more groups of admission nozzle passages 28 of which only one nozzle passage is shown. The spindle 24 is provided with a circumferential row of spaced, axially extending blade retaining grooves 29. The cross-sectional configuration of the grooves 29 conforms with the crosssectional configuration of'the slotted blade root i, and the blade structures are inserted'into the grooves by movement in a lateral direction with respect to thecircumferential blade row. The grooves 2,9 may be finished by a single broaching operation. and may be of any desired length in order to form a plurality of circumferentially extending blade rows.

The axial spacing of the blade forming structures is accomplished bymeans of a slotted spacing block 3| disposed between the blade forming, structures in each axial groove, and in order to facilitate removal of the blade structures, and to reduce machining costs, the space 32, lying above the spacing block 31 and between the circumferential blade rows. may he provided by cutting a circumferentially extending groove having a cross-sectional configuration conforming with the plane space 82; as shown in Fig. 2', and similarly located with respect to the end of the spindle before cutting the axially extending blade retaining grooves 29. The spindle 24 is provided with circumferential retaining grooves 33. and the adjacent bottom edges of the blade forming structures are cut away to form a continuation of the groove throughout the axially grooved portions of the spindle when the blade structure's are-in place. Any suitable means may beinserted in'lthe grooves 33 for preventing movement of the'blade' structures in a lateral direction with respect to the blade row. The

means illustrated comprises a retaining ringj4,

which is generally made in segments. and is inserted in a knowrl manner.

The blades of the-stationary blade row 26 are provided with'sealing projections 38; which coact with the sealing surfaces 20 of the moving blades to prevent the passage of the driving fluid around,

the 'ends of the stationaryfblades. The moving blades are generally provided with means adapted to coact with sealing surfaces on the casing 21 for a similar purpose. However, the means for sealing the spaces adjacent the ends of the moving blades have not been disclosed as they are not deemed essential for an under'-. standing of the invention. In addition, it should be borne in mind that the disclosed blade structure' retaining means, the slotted root and groove. requisite is that the spindle be provided with a circumferential row of spaced blade retaining means into which a part of the supporting por- 76 or channel is defined by spaced concave convex are merely illustrative,' as the only surfaces disposed in hosted or in partially nested relationship.

The invention is obviously applicable to spindles employing only a single circumferential blade row, and in this connection it should be borne in mind that the disclosed relative dimensions and arrangement of parts are merely illustrative and may "be materially altered without departing from the spirit of the invention. Therefore, it should be. understood that it is not desired to limit the invention to the exact details of construction herein shown and described. for various modifications within the scope of the claims may occur to persons skilled in the art.

1. A turbine blade forming structure compris ing a supporting portion and spaced complementary blade forming members extending from said supporting portion and presenting opposed surwith respect to said opposed passage definingsurfaces and arranged for sliding engagement and coincident contact with the side surface of a complementary blade forming member on an adjacent blade structure so that when the blade structures are arranged to form a blade row, the side surfaces of the blade forming members on adlacent structures will be in substantial coinciv dence and said members on adjacent structures will coact and form blades having contiguous fluid directing surfaces.

2. A turbine blade forming structure comprising a supporting portion and spaced members extending from said supporting portion and presenting opposed surfaces, one of which is concave and the other convex. defining therebetween a channel for the passage of the driving fluid, said members each having a plane surface oppositely disposed with respect to said opposed surfaces and dimensioned for coincident contact with the abutting surface, of a member on an adjacent blade structure. and the member embodying said concave surface also having oppositely disposed plane side surfaces each of which is substantially'tangential with respect tothe convex surface at the adjacent and of the channel of the next adjacent blade structure.

3. A turbine blade forming structure comprising a supporting portion. spaced members extending from. said supporting portion and presenting opposed surfaces, one of which is concave and the other convex, defining therebetween a channel for the passage of the driving fluid. said members each having a plane surface oppositely disposed with respect to said opposed surfaces and dimensioned for coincident contact with the abutting surface ofa-member on an adjacent blade structure. and the member embodying said concave. surface also having oppositely disposed plane side surfaces each of which is substantially tangential with respect to the convex surface at the adjacent end of the channel of the next adjacent blade structure, and means coacting with portions ofsaid spaced members remote from said supportingportion and defining with said supporting portion and spaced members a sealed fluid confining passage.

'4. A turbine blade forming structure comprising a supporting portion, spaced members extending from said supporting portion and presenting opposed surfaces. one of which-is concave and the other convex, defining therebesurfaces and dimensioned for coincident contact with the abutting surface 'of a member on an adjacent blade structure, and the member embodying said concave surface also having oppositely disposed plane side surfaces each of which is substantially tangential with respect to the convex surface at the adjacent end of the chanml of the next adjacent blade structure. and a top portion extending beyond each of said plane side surfaces and overlying said supporting por-- tion, and means coacting with said spaced members and with said top portion and defining with said supporting portion and spaced members a sealed fluid confining passage.

5. A turbine blade forming structure comprising a supporting portion, a first means extending from said supporting portion and having.

sides including a concave surface, oppositely disposed planesurfaces each of which is approximately tangential with respect to the adjacent edge of said concave surface and another plane surface oppositely disposed with respect to said concave surface, and a second means extending from saidsupporting portion in spaced and partially nested relationship with respect to said Y first means and having sides including a convex surface oppositely disposed with respect to said concave surface and a plane surface oppositely disposed with respect to said convex surface and with respect torsaid another plane surface on said first means, said another surface and the plane surface on said second means being adapt-.

ed for sliding engagement and dimensioned for coincident contact with the abutting surfaces of members on adjacent blade structures.

6. A turbine blade forming structure comprising a supporting portion, a first means extending from said supporting portion and having sides including a concave surface,. oppositely disposed plane surfaces each of which is approximately tangential with respect to the adjacent edge of said concave surface and another plane surface oppositely disposed with respect to said concave surface, a second means extending from said supporting portion in spaced and partially nested relationship with respect to said first means and having sides including a convex surface oppositely disposed with respect to said concave surface and a plane surface oppositely disposed with respect to said convex surface and with respect to said another plane surface on said first means, said first means also having a top portion extending beyond said oppositely disposed plane surfaces and overlying said supporting portion. and said another surface and the plane surface on said second means being adapted for sliding engagement and dimensioned for coincident con-r tact with the abutting surfaces on adjacent blade structures, and means coacting with said first and second means and with said extending top portion and defining with said extending top portion. with said first and second means and with said supporting portion a. sealed fluid confining passage.

7. A turbine blade assembly comprising a spin dle having a circumferential row of spaced blade retaining means into which part of the supporting portion of a blade structure is inserted by moving the blade structure in a'lateral direction with respect to said row and blade structures each having a supporting portion, and-coacting with said retaining means on said supporting messes portion forming spaced complementary blade forming members each constituting a portion of a complete blade and having oppositely disposed side surfaces arranged for sliding engagement and'dimensioned for coincident contact with the side surfaces of members on adjacent blade structures so that said members on adjacent structures coact and form blades each having contiguous fluid directing surfaces.

8. A turbine blade assembly comprising a spindle having a circumferential row of spaced blade retaining means into which part of the supporting portion of a blade structure is inserted by moving the blade structure in a lateral direction with respect to said row and blade structures each having a supporting portion, spaced complementary blade forming members each constituting a portion of a complete blade extending from said supporting portion and presenting opposed passage defining surfaces and having side surfaces oppositely disposed with respect to one another and with respect to said. passage defining surfaces, said side surfaces being adapted for sliding engagement and dimensioned for coincident contact with the side surfaces of members or adjacent blade structures so that said members on adjacent blade structures coact and form blades having contiguous fluid passage directing surfaces, and means coacting with portions of said spaced members remote from said supporting portion and defining with said spaced members and supporting portion a sealed fluid confining passage.

9. A moving blade assembly for elastic fluid turbines permitting the separate insertion and removal of any individual blade structure from a row of blades in which spaced concave convex fluid passage defining surfaces are disposed in nested or in partially nested relationship comprising a spindle having a circumferential row of spaced, axially extending grooves and blade structures each having a supporting portion including a part slidable into and out of said grooves by movement in a direction generally parallel with respect to the spindle axis, and means on said supporting portion forming complementary blade members each constituting a portion 'of a complete blade and having a side surface arranged for sliding engagement and coincident contact with the side surface of a member on an adjacent blade structure and a fluid directing surface adjoining said side surface and so arranged that said members on adjacent structures coact and form blades having contiguous fluid directing surfaces.

10. A turbine blade assembly comprising a.

spindle having a circumferential row of spaced blade retaining means into which the retaining portion of a blade structure is inserted by moving the blade structure in a lateral direction with respect to said row and blade structures each having a supporting portion, spaced memsurface at the adjacent and of the'channel of the next adjacent blade structure so that said members on adjacent structures coact and form blades having contiguous concave-convex fluid passage directing surfaces, a top portion extending beyond each of said plane side surfaces andoverlying said supporting portion, and means coacting with said spaced members and with said top portions and defining with said supporting portion and spaced members asealed fluid confining passage.

11. A turbine blade assembly comprising a faces and dimensioned for coincident contact with the side surfaces of members on adjacent blade structures and the member embodying said concave surface also having oppositely disposed plane side surfaces each of which is substantially tangential with respect to the convex surface at the adjacent end of the channel of the next adjacent blade structure so that the members on adjacent structures coact and form blades each having contiguous concave-convex fluid passage directing surfaces, a top portion extending beyond eachof said plane side surfaces and overlying said supporting portion, and means coacting with said spaced members and with said top portions and defining with said supporting portion and spaced members a sealed fluid confini p 12. A turbine blade assembly comprising a spindle having a circumferential row of spaced blade retaining means into which part of the supporting portion of a blade structure is inserted by moving the blade structure in a lateral direction with respect to said row and blade structures, each having a supporting portion, spaced members extending from said supporting portion and presenting opposed surfaces, one of which is concave and the other convex, defining therebetween a channel for the passage of the driving fluid, said members each having a plane side surface oppositely disposed with respect to said opposed surfaces and dimensioned for coincident contact with the side surfaces of members on adjacent blade structures and the member embodying said concave surface also having oppositely disposed plane side surfaces each of which is substantially tangential with respect to the convex surface at the adjacent end of the channel of the next adjacent blade structure so that the members on adjacent structures coact and form blades each having contiguous concaveconvex fluid directing surfaces, a top portion extending beyond each of said oppositely disposed plane side surfaces and overlying said supporting portion, and means coacting with said spaced members and with said top portions and defining with said spaced member and supporting portion a sealed fluid confining passage.

13. A turbine blade forming structure comprising a supporting portion and two complementary blade forming members extending from said supporting portion in spaced relation, each of said members constituting a portion of a complete blade and each of said members being the coinplement of that portion of a complete blade defined by the other of the said two members.

14; A turbine blade forming structure comprising a supporting portion and two spaced complementary blade forming members extending from said supporting portion and presenting'opposed concave-convex passage defining surfaces disposed in partially nested relationship, each of said members constituting a portion of a complete blade, and each of said members being the complement of that portion of a complete blade defined by the other of the said two members.

15. A turbine blade assembly comprising adjoining structures each having a supporting portion and two blade forming members extending from 'said supporting portion in spaced relation, each of said members constituting a portion of a complete bladeand each of said members being the complement of that portion of a complete blade defined by the adjacent member on an adjoining structure, said members each having a similarly disposed side surfacearranged for sliding engagement and coincident contact with the like surface of the adjacent member on an adjoining structure, and said adjacent members on adjoining structures coacting to form blades each having contiguous fluid directing surfaces.

16. A turbine blade forming structure having oppositely disposed side surfaces arranged for sliding engagement and coincidentcontact with the like surfaces of adjacent structures comprising a supporting portion having oppositely disposed sides and a complementary blade forming member extending from said supporting portion adjacent each of said sides, said members being disposed in spaced relaticn so as to form therebetween a passage for the driving fluid, each of said members constituting a portion of a complete blade and being the complement of that portion of a complete blade defined by the other of the said two members, and each of said members including a side surface which forms a continuation of the adjacent one of said sides on said supporting portion and forms therewith one of the 'said oppositely disposed side surfaces on said structure.

JAMES L. RAY.

CERTIFICATE OF coRREcTIom Patent No. 2,255 ,569.- February 2 191p;

JAMES L. RAY. i

It is hereby certified that error a ipears izi the printed epecifipatien of the above numbered patent requiring correction aefoilows: Page l sec- 0nd column, line 26, claim 8, for the word "or" read on-fend that the said Letters Patent should be reed with'this 'cbrrecti'on thereiiz that the sflme may conform to the record Of .the case in the',Patent Office.

Signed and sealed this 25th day of March, A.- D. 191m.

. V Henry Van Aradale (Seal) I Acting Commissioner of Patents.