US1077300A

US1077300A - Axial-flow steam-turbine.

Info

Publication number: US1077300A
Application number: US73560212A
Authority: US
Inventors: Charles Bemis Rearick
Original assignee: CONNECTICUT TURBINE Manufacturing Co
Current assignee: CONNECTICUT TURBINE MANUFACTURING Co
Priority date: 1912-12-09
Filing date: 1912-12-09
Publication date: 1913-11-04
Anticipated expiration: 1930-11-04

Description

C. B. REARICK..

' AXIAL FLOW STEAM TURBINE.

APPLICATION FILED Dnc. 9, 1912.

Patented Nov. 4, 1913.

Z SHEETS-SHEET l.

WITNESSES manners n COLUMBIA PLANGGRAPH cD.,wAsHxNn1'IJN. D. c.

0. B. REARICK.

AXIAL PLOW STEAM TURBINE.

APPLIUATION FILED 1330.9, 1912.

Patented Nov. 4, 1913.

2 SHEETS-SHEET 2.

mann/frs CULUMEIA FLANQURAPH Co., WASHINGTON. D. C.

UNITED sTATEs PATENT orme.

CHARLES BEIVIIS REARICK, OF NEW LONDON, CONNECTICUT, ASSIGNOR T0 CONNECTI- CUT TURBINE MANUFACTURING COMPANY, OF

CORPORATION OF CONNECTICUT.`

NEW LONDON, CONNECTICUT, A

AXIAL-FLOW STEAM-TURBINE.

This invention relates to axial flow tur-y bines for use with steam or other elastic motive fluid, the turbine wheels being vpreferably cast with a number of annular series of inclined stepped curved buckets with which cooperate suitable nozzle andreturn members provided with curved return passages preferably arranged at dilferentiangles tov assist in securing the desired increase of area of i the bucket and return passagesas the steam passes the desired number of times throughV the various wheel buckets. The turbine wheel may also be formed with especially `arranged expansion spokes of material having generally similar expansion to the wheel rim Vwhich may have their inner ends secured to the hub while` the body o-f the spokes is loosely embraced in any desired way by spoke supports which may be cast integral with the wheel hub, if desired. l

In the accompanying drawing showing in a somewhat diagrammatic mannerV an illustrativeembodiment of the invention, Figure 1 is a partial axial section taken along the line 1 1 of Fig. 2 in'which the wheel buckets and return passages have been turned up into the line of section to more clearly show their construction. Fig. 2 is a transverse sectional view taken along the line 2-2, 21-2a and the other section lines shownrin Fig. 1 to the extent indicated on Fig. 2 so as to show thereinmore clearly the arrangement of the various sets of wheel buckets and return passages. Fig. 3 is a developed flow diagram in which the return members and passages are shown in dotted section.

In the illustrative embodiment of this invention shown in the drawings, the turbine wheel may be formed in any desired way with the selected number of annular series of wheel buckets having the desired form and the wheel rim and' buckets may be conveniently cast in one piece of speciallyl strong bronze or other suitable material as Specicaton of Letters Patent.

Application led December 9, 1912.

Patented Nov. 4, 191s. Serial No. 735,602. Y

by the process covered by the Hopson and Rearick Patent No. 1,008,478, of November 14, 1911.

Suitable spokes preferably of bronze or other material having substantially the same o-r slightly greater co-e'fiicient of expansion than the rim material are preferably formed integral with or otherwise secured to the rimwhich may be conveniently done by casting the rim around the same, the spokes 26 having as indicated in Figs. l and2 suitably formed projections, such as the annu- `lar ribs 37 which are strongly -gripped by the inclosing portions of the rim material which vmay have 4suitable inwardly projecting lugs 47 extending from the rim 5. The inner ends of these spokes which are preferably formed' with gripping projections such as the annular projections 36 may be conveniently secured to the wheel as by casting the steel, cast iron or other suitable metal used for the hub 48 around them so as to firmly grip the inner ends of the spokes thus effecting relief of original casting strains in rim and spokes; if desired the 'hub metal may extend outalong the spokes so as to form spoke supports laterally sup porting the spokes throughout the desired extent while preferably allowing the longitudinal expansion ofthe spokes beyond the point at which their inner ends are secured `to the hub. For some reasons it is desirable in order to insure the accurate alinement of these spokes during such expansion as takes place under operating conditions to interpose a spoke sleeve 25 of steel or other suitable material around each of the spokes 26 before casting the hub metal 48 around the spokes so as to rigidly secure their inner ends in position, this metal` preferably extending around the spoke sleeve throughable admission passage 2 which may be cast integral with the casing if desired and within this casing there may be mounted in any desired way a series of nozzle members and return passages each of which may if de-A sired be in the form of an integral casting 22 having a nozzle tube 3 held in the casing in any desired way so as to support the nozzle and return member in position in proper cooperation with the wheel. f desired suitable alining pins l12 may be formed in the nozzle and return members so as to cooperate with suitable alining sockets, such as 13, in the adjacent members and assist in holding the members in proper circumferential alinement. As shown in Figs. 1 and 3 cach of these nozzle and return members may be provided with a series of inj ecting nozzles et arranged to copei'ate with the first set of buckets 6 in the wheel. These return members 22 may be formed as by casting them integral therein with a number of series of return passages adapted to return the steam received from each set of wheel buckets into the succeeding set so that the steam is passed the desired number of times through the wheel buckets to eXert additional propelling impulses thereon. As shown in Fig. 2 by the line of arrows the steam naturally advances somewhat in the direction of motion of the turbine wheel during its passage axially across the saine through the different series of bucket-s. For this reason the dierent return passages in this return member may be arranged in a generally diagonal direction, it being, however, desirable to arrange special trailing and advance return passages to receive the steam in the first set of return passages7 for instance, when the injecting nozzles are in line with one of the partitions between the wheel buckets. For this purpose the special or trailing return passage 27 may be provided in each return member 22 to receive this backwardly di-` verted or backsplit steam and a similar advance return passage 28 may be provided at the other end of this first series of' return passages 10. For similar reasons the trailing return passage 30 and the advance return passage 29 may be provided at either end of' the similarly shaped ret-urn passages 12 in the second set. ln the third set the regular return passages are 17 and the trailing return passage 32 and the advance return passage 31 and in the fourth set of return passages which may be used in these return members with advantage in some cases the regular return passages are 2O and the trailing return passage 33 and the ad- Vance return passage 34.' In order to prevent clogging of steam, it is desirable to form the ret-urn members 22 so that they are somewhat separated from the adjacent return members as by the relief spaces 4:4, l5 and 46. It is desirable to form the annular partitions between the ditlerent sets ot' return passages and wheel buckets with curved annular recesses such as a9, 50 which serve to receive any surplus steam beyond what can conveniently enter the succeeding return passage or wheel bucket and curve it around so as to again direct it against the inner side into this stream of motive fluid.

Tie steam originally injected into the first set of wheel buckets from the injecting nozzles t has a high velocity and corspondingly high kinetic energy. At each pass through the wheel buckets the velocity and kinetic energy are reduced so that the stream of' motive fluid thus has an increased volume at each pass which should be accommodated by increasing the available ciosssection of the succeeding wheel buckets and return passages. This can be effectively done by increasing the angle at which the steam is injected into the succeeding sets of buckets and also by increasing the axial width across the curved row of wheel buck-` ets or return passages so as to allow a greater width to the curved stream of steam passing therethrough or if desired the succeeding.`

set of' wheel buckets for instance may both have an increased angle and a greater width so as to secure through both these factors the desired increase-in available cross-section and accommodate the increased volume pendicular distance between the partitions* of this set of buckets, that is, their bucket height correspondingly small. rlhe steam passing through this first set of buckets G is under normal operating conditions discharged therefrom at a correspondingly greater angle due to its reduced velocity and the wheel motion and the first set of return passages 10 into which the steam passes have their receiving throats or sides 7 arranged as shown in Fig. 1 at a greater angle substantially equal to the angle at which the steam is discharged from the first wheel buckets, as shown in dotted lines in Fig. 2. The steam is with a minimum of disturbance or eddying received and guided around from the returning or injecting sides 8 of these buckets int-o the second set of wheel buckets 9. This second set of wheel buckets 9 are shown in full lines in that part of Fig. 2 in which the section is taken along the lines 2 of Fig. 1 and as indicated `the increased angle which these wheel buckets 9 make with the wheel circumference at that point correspondingly increases the perpendicular distance between the partitions of thisset o-f wheel buckets so as to secure an increased height of buckets and corresponding increase in their effective area or capacity. The steam from the returning sides 8 of the return passages 10 entering these wheel buckets 9 leaves them at a still greater angle and to receive this steam under most advantageous conditions the seco-nd set of return passages 12 have their receiving ends 11 arranged at substantially the angle of the steam entering from the wheel buckets 9 as shown by the dotted lines in this part of Fig. 2. This set of intermediate return passages 12 is preferably` warped so as to guide the steam received into their receiving ends 11 at a considerable angle so that when again delivered into the succeeding set of wheel buckets 14 from the returning sides 13 of these return passages 12 the steam makes a considerably .less angle to the wheel circumference. This is shown quite clearly in the sectional view through these return passages taken along the line 2b of Fig. 1 which is shown in that part of Fig.

2 which is correspondingly designated. TheV receiving ends 11 of these warped return passages are therein indicated in dot and dash lines as being in front of the line of section and the steam is shown as being guided by these warped buckets so as to be discharged from their returning sides 13 at a considerably sharper angle so as to properly coperate with the sharp angle wheel buckets 14. These wheel buckets as indicated in Fig. 1 are given a considerably greater axial width in order to properly accommodate in their comparatively slight height the increased volume of steam during this pass through the wheel.V The increase in axial width ofthe wheel buckets 9 as compared with the first set of wheel buckets 6 contributes to their increased carrying capacity as does also their increased angle as compared with the first set of wheel buckets 6.

As shown in Fig. 2 t-he steam discharged from the wheel buckets 14 passes Ainto the dotted receiving ends 15 of the return pasvsages 17 which are shown in full rines in the succeeding section on 2c so thatthe steam may be definitely guided around in the same plane in these fiat buckets 17 so thatwhen discharged from their returning sides 16 it has a considerably greater angle and properly enters the fourth set of wheel buckets 18 which have a correspondingly greater height because of their greater angle for which reason their axial width need not be any greater and may in some cases be even less than the axial width of the wheel buckets 14. The steam discharged from these wheel buckets 18 is directed in line with the dotted receiving sides 19 of the last set of return passages 20, so that when discharged from their returning sides 21 shown in full lines in the section on 2d at the bottom of Fig. 2 the steam is directed at a very much greater angle to this part of the wheel circumference, so that the wheel buckets have a much greater height and e'ective area and can properly accommodate the increased volume of this slower moving steam which is indicated as being discharged directly into the wheel chamber from this last set of buckets.

By arranging the receiving sides of one or more of the sets of return passages at about the angle at which the steam is discharged from the preceding set of wheel ybuckets the steam is returned to the succeeding set of wheel buckets when each of the return passages is substantially iiatata suf,

iiciently greater angle to materially increase the effective area of the wheel buckets when formed with substantially the same axial width and thickness of partition. In this way it is possible to largely or wholly eliminate the use of warped wheel buckets or return passages which are less desirable from the const-ructional standpoint because. of the increased difficulty of properly forming or finishing them and which are somewhat undesirable because ofthe increased frictional losses involved. In order to most readily finish wheel buckets or return passages of this'character they are preferably formed with somewhat elliptical or flattened curved bottoms so as lto allow the use of a" buiiing or finishing tool to best advantage. In Fig. 1 the flattened curved bottoms of these bucketsare designated 51, the buckets being sufficiently shallow to considerably facilitate finishing in this way.

Having described this invention in convnection with a number of illustrative embodiments, forms, proportions, numbers of parts, arrangements, materials and processes and forming integral spoke supports loosely surrounding said spokes and allowing` their radial expansion and said plates secured to said rim to inclose said spokes, said Wheel buckets being substantially tlat and a. num

ber of the succeeding sets of said Wheel buckets being arranged at a greater angle to the Wheel circumference than the preceding set, a series of' return members mounted to cooperate with said wheel, each of said members being provided With a number of sets of curved return passages cooperating with the sets of Wheel buckets, one or more sets ol" return passages being substantially flat and arranged at a greater angle than the Wheel buckets from Which they receive fluid.

2. In axial fioW elast-ic fiuid turbines, a cast turbine Wheel rim provided With a number of annular sets of lapping curved buckets, bronze expansion spokes secured to said rim, a Wheel hub being formed of cast ferrous metal of less co-efficient of' expansion embracing and gripping said spokes adjacent their inner ends, said Wheel buckets being substantially flat and a. number ot the succeeding set of said Wheel buckets being arranged at a greater angle to the Wheel circumference than the preceding set, a series of return members mounted to cooperate with said Wheel, each of said members being provided with a number of sets of curved return passages cooperating with the sets of wheel buckets, one or more sets of return passages being substantially fiat and arranged at a greater angle than the Wheel buckets Jfrom which they receive fiuid.

3. In axial flow elastic fluid turbines, a cast turbine Wheel rim provided with a number or" annular sets oit' lapping curved buckets, bronze expansion spokes secured to said rim, a Wheel hub being formed ot metal of less co-eflicient of expansion embracing and gripping said spokes adjacent their inner ends, said Wheel buckets being substantially fiat and a succeeding set of said Wheel buckets being arranged at a greater angle to the Wheel circinnference than the preceding set, a series of return members mounted to coop-erate with said wheel, each of said members being provided with a number of sets of curved return passages cooperating with the sets of Wheel buckets.

et. In axial fiow elastic fluid turbines, a cast bronze turbine Wheel provided With a number of annular sets of lapping curved buckets, said Wheel buckets being substantially flat and anumber of the succeeding sets oi said Wheel buckets being arranged at a greater angle to the wheel circumference than the preceding set and a number of the succeeding sets of said wheel buckets having a greater axial Width than the preceding set, a series of nozzle and return members mounted to cooperate with said Wheel, each of said members being provided with `cast turbine Wheel provided with a number lof annular sets of lapping curved buckets, said Wheel buckets being substantially flat and a number of the succeeding sets of said wheel buckets being arranged at a greater tangle to the Wheel circumference than the `preceding set and a succeeding set of said fivheel buckets having a greater axial Width ithan the preceding set, a series of nozzle vand return members mounted to cooperate with said Wheel, each of said members being provided with a plurality of' inject-ing nozzles to cooperate with the first set of Wheel buckets and with a number of sets of curved return passages cooperating with the succeeding sets of Wheel buckets, one or more sets of' return passages being substantially flat and arranged at a greater angle than the Wheel buckets from which they receive fluid.

6. In axial flow elastic fluid turbines, a cast turbine Wheel provided With a number of annular sets of lapping curved buckets, said Wheel buckets being substant-ially flat and a succeeding set of said Wheel buckets being arranged at a greater angle to the Wheel circumference than the preceding set and a succeeding set of' said Wheel buckets having a greater axial Width than the preceding set, a series of nozzle and return members mounted to -cooperate With said Wheel, each of said members being provided With an injecting nozzle to cooperate With the first set of wheel buckets and With a number or sets of curved return passages cooperating With the succeeding sets of Wheel buckets, one or more sets of return passages being substantially flat and arranged at a greater angle than the Wheel buckets from which they receive fluid.

7. In axial flow elastic fluid turbines, a turbine wheel provided with a number of annular sets of lapping curved buckets, said Wheel buckets being substantially flat and a succeeding` set of said Wheel buckets being arranged at a greater angle to the Wheel circumference than the preceding set, a series of nozzle and return members mounted to cooperate With said Wheel, each of said members being provided with an injecting nozzle to cooperate with the first set of Wheel buckets and with a number of sets of curved return passages cooperating with the succeeding sets of Wheel buckets, one or more sets of return passages being substany tially flat and arranged at a greater 'anglethan the Wheel buckets frein which they receive fluid. i

S. In axial flow elastic iiuid turbines, a

turbine Wheel provided with a'numb'er of annularsets of lapping curved buckets, said Wheel buckets being substantially flat and a succeeding set of said Wheel buckets being arranged at a greater angle to the Wheel circumference than the preceding set, a series of nozzle and return members mounted to cooperate With said Wheel, each of said members being provided with an injecting nozzle to cooperate With the' lirst set Aof Wheel buckets and With a number of sets of curved ret-urn passages cooperating with the succeeding sets of Wheel buckets.

9. In axial flow elastic iiuid turbines, a turbine Wheel provided With a number of annular sets of lapping curved buckets, said Wheel buckets being substantially flat and a number of thesucceeding sets of said Wheel buckets being arranged at a greater angle to the Wheel circumference than the preced-Y ing set and aV number of the succeeding sets of said Wheel buckets having a greater axial Width than the preceding set, a series of re turn members mounted to cooperate With said Wheel, each ofsaid membersbeing provided With an injecting nozzle to cooperate with the first set of Wheel buckets and with a number of sets of curved return passages cooperating With the succeeding sets of Wheel buckets, one or more sets of return passages being arranged to deliver fluid at a greater angle than the wheel buckets from which they receive fluid.

10. In axial iioiv elastic fluid turbines, a turbine Wheelr provided with a number of annular sets of lappingcurved buckets, said wheel buckets being substantially iat and a number of the .succeeding sets of said Wheel buckets being arranged at a greater angle to the Wheel circumference than the preceding set, a series of return members mounted to cooperate with said wheel, each of said members being provided with an injecting nozzle to cooperate with the first set of Wheel buckets and with a set of curvedreturn passages cooperating with the succeeding set of Wheel buckets, one or more sets of return passages being arranged to deliver fluid at a greater angle than the Wheel buckets from which they receive fluid.

11. vIn axial flow elastic iui'd turbines, a turbine Wheel provided with a number of annular sets of lapping curved buckets, saidl Wheel buckets being substantially flat and? a number of the succeeding sets of said Wheel buckets being arranged at a greater angle to the wheel circumference than the-preceding set.

12. In axial'flovv elastic fluid turbines, a turbine Wheell pro-vided With a number of annular sets of lapping curved buckets, said Wheel buckets being'substantially flat and a succeeding setof said Wheel buckets being arranged at a greater angle to the Wheel circumference than the preceding set.

13. In axial flovv elastic fluid turbines, a turbine Wheelv provided with a number of annular sets of lapping curved buckets, a succeeding lset of said Wheel buckets being arranged at a greater angle to the Wheel circumference than thefpreceding setf 14. In axial tiotv elastic fluid turbines, a turbine Wheel provided with .a number of annular sets of lappingcurved buckets, a succeeding set :of said Wheel buckets being arranged at a greater angle to the Wheel circumference than. the preceding set and a succeeding set of said Wheel buckets having a greater axial Width than the preceding set.

15. In axial flow elastic fluid turbines, a turbine Wheel provided With a number of annular sets of lapping curved buckets, there being annular curved recesses in the edges of the `partitions separating the dif-v ferent sets of buckets, a return member mounted to cooperate with said Wheel, and provided with a number of'sets ofv curved return passages cooperating With the 'sets of Wheel buckets, there being annular curved recesses formed in the edges of the partitions betyveen the different setsv of return passages.

16. In axial flow elastic fluid turbines,l a turbine Wheel provided With aV number of. annular sets of lapping curved buckets, a succeeding set of said Wheel buckets being arranged at a greater angle to the Wheel circumference than a preceding set, there being annular curved recesses in the edges of the partitions separating the different sets of buckets, a return member mounted to `cooperate With said Wheel, and provided with a number of sets of curved return passages cooperating with the sets of Wheel buckets, there being annular curved recesses formed in the vedges of the partitions between the dierent sets of return passages.

17. In axial flow elastic fluid turbines, a turbine Wheel provided With a number of annular setsof lapping curvedbuckets, a succeeding set ofsaid Wheel buckets being arranged at a greaterangle to the Wheel circumference than a preceding set, there being annular curvedrecesses in the edges of the partitions separating *the different sets of buckets, a return member mounted to cooperate with said' Wheel, and provided with a number of sets of curved return passages cooperating vvith the sets of Wheel buckets.

1S. In axial-flow elastic--fluid turbines, a

`*turbine Wheel provided with a number of annular sets of lapping curved buckets, a

succeeding set of said wheel buckets beingV arranged at a greater angle to the wheel circumference than a preceding set, a return member mounted to cooperate with said wheel, and provided with a number of sets of curved return passages cooperating with the sets of wheel buckets, there being annular curved recesses formed in the edges of the partitions between the different setsV of return passages.

19. In axial flow elastic fluid turbines, a cast turbine wheel provided with a number of annular sets of lapping curved buckets, there being annular curved recesses in the edges of the partitions separating the different sets of buckets, a series of cast integral nozzle and return members mounted to cooperate with saidY wheel, each of said members being provided with a plurality of injecting nozzles to cooperate with the first set of wheel buckets and with a number of sets of curved return passages cooperating with the succeeding sets of wheel buckets and advancing substantially diagonally across said wheel, there being annular curved recesses formed in the edges of the partitions between the different sets of return passages and there being relief spaces between adjacent members to allow premature escape of retarded motive fluid from said wheel buckets.

20. In axial flow elastic fluid turbines, a turbine wheel provided with a number of annular sets of lapping curved buckets, there being annular curved recesses in the edges of the partitions separating the different sets ot buckets, a series of nozzle and return members mounted to cooperate with said wheel, each of said members being provided with an injecting nozzle to cooperate with the first set of wheel buckets and with a number of sets of curved return passages cooperating with the succeeding sets of wheel buckets and advancing substantially diagonally across said wheel, there being annular curved recesses formed in the edges of the partitions between the different sets of return passages and there being relief spaces between adjacent members to allow premature escape of retarded motive fluid from said wheel buckets.

2l. In axial flow elastic fluid turbines, a turbine wheel provided with a number of annular sets of lapping curved buckets, a series of' nozzle and return members mounted to cooperate with said wheel, each of said members being provided with an injecting nozzle to cooperate with the first set of wheel buckets and with a number of sets of curved return passages cooperating with the succeeding sets of wheel buckets and advancing substantially diagonally across said wheel, and there being relief spaces between adjacent members to allowpremature escape of retarded motive fluid from said wheel buckets.

22. In axial tlow elastic fluid turbines, a turbine wheel provided with a number of annular sets of lapping curved buckets, a series of nozzle and return members mount ed to cooperate with said wheel, each of said members being provided with an injecting nozzle to cooperate with the first set of wheel buckets and with a set of curved return passages cooperating with the succeeding set of wheel buckets and there being relief spaces between adjacent members to allow premature escape of retarded motive fluid from said wheel buckets.

23. In axial flow elastic fluid turbines, a turbine wheel provided with a number of annular sets of curved buckets, a series of re turn members mounted to cooperate with said wheel, each of said members being pro vided with a number of sets of curved return passages cooperating with the succeeding sets of wheel buckets and advancing substantially diagonally across said wheel, there being relief spaces between adjacent members to allow premature escape of' retarded motive fluid from said wheel buckets.

24. In axial flow elastic fluid turbines, a turbine wheel provided with a niunber of annular sets of curved buckets, a series of return members mounted to cooperate with said wheel, each of said members being provided with a set of curved return passages cooperating with the succeeding set of wheel buckets, there being relief spaces between adjacent members to allow premature escape of retarded motive fluid from said wheel buckets.

25. In axial flow elastic fluid turbines, a cast turbine wheel provided with a number of annular sets of lapping curved buckets, a series of nozzle and return members mounted to cooperate with said wheel, each of said members being provided with one or more injecting nozzles to cooperate with the first set of wheel buckets and with a number of sets of curved return passages cooperating with the succeeding sets of wheel buckets and advancing substantially diagonally across said wheel, there being trailing return passages formed in said return members arranged behind the nozzle cooperating with such members and there being relief spaces between adjacent members to allow premature escape of returned steam from said wheel buckets.

26. In axial flow elastic fluid turbines, a cast turbine wheel provided with a number of annular sets of lapping curved buckets, a series of nozzle and return members mounted to cooperate with said wheel, each ofI sai-d members being provided with one or more injecting nozzles to cooperate with the first set of wheel buckets and with a number of sets of curved return passages cooperating With the succeeding sets of Wheel buckets, there being trailing return passages formed in said return members arranged behind the nozzle coperat-ing With such members, and there being relief spaces between adjacent members to alloW premature escape of returned steam from said Wheel buckets.

27. In axial floW elastic fluid turbines, a cast turbine Wheel provided With a number of annular sets of lapping curved buckets, a series of separate nozzle and return members mounted to coperate With said Wheel, each of said members being provided With one or more injecting nozzles to cooperate With the first set of Wheel buckets and With a set of curved return passages cooperating With the succeeding set of Wheel buckets, there being trailing return passages formed in said return members arranged behind the nozzle cooperating With such members.

28. In axial floW elastic fluid turbines, a cast turbine Wheel provided With a number of annular sets of lapping curved buckets having flattened curved bottoms, a plurality of injecting nozzles to coperate With one Vset of buckets and return members provided With a number of sets of curved return passages cooperating With succeeding sets of Wheel buckets, said Wheel buckets being substantially flat and a number of the succeeding sets of said Wheel buckets being arranged at a greater angle to the Wheel circumference than the preceding set and a number of the succeeding sets of said Wheel buckets having a greater axial Width than the preceding set, one or more sets of return passages being substantially flat and arranged at a greater angle than the Wheel buckets from Which they receive motive fluid and one of said sets of return passages being Warped and arranged to return the fluid to the Wheel buckets at a less angle to the Wheel circumference than said fluid Was received to pass the motive iiuid a numberof times through said Wheel buckets at progressively increasing angles and to reduce the angle of returning fluid before again passing it through the Wheel buckets at progressively increasing angles.

29. In axial iioW elastic fluid turbines, a turbine Wheel provided With a number of annular sets of lapping curved buckets, a plurality of injecting nozzles to cooperate With one set of buckets and return members provided With a number of sets of curved return passages cooperating With succeeding sets of Wheel buckets, said Wheel buckets being substantially flat and a number of the succeeding sets of said .Wheel buckets being arranged at a greater angle to the Wheel circumference than the preceding set, one or more sets of return passages being substantially flat and arranged at a greater angle Y than therWheel buckets from Which they receive motive fluid and one of said sets of return passages being Warped and arranged to return the fluid to the Wheel buckets at a less angle to the Wheel circumference than said iuid Was received to pass the motive fluid a number of times through said Wheel buckets at progressively increasing angles and to reduce the angle of returning fluid before again passing it through the Wheel buckets at progressively increasing angles.

30. In axial oW elastic fluid turbines, a turbine Wheel provided With a number of annular sets of lapping curved buckets, a plurality of injecting nozzles to coperate With one set of buckets and return members provided With a number of sets of curved return passages cooperating With succeeding sets ofl Wheel buckets, a number of the succeeding sets of said Wheel buckets being arranged at a greater angle tothe Wheel circumference than the preceding set, vone or more sets of return passages being substantially flat and arranged at a greater angle than the Wheel buckets from Which they receive motive fluid and one of said sets of return passages being Warped and arranged to return the fluid to the Wheel buckets at a less angle to the Wheel circumference than said fluid Was received to pass the motive fluid a number of times through said Wheel buckets at progressively increasing angles and to reduce the angle of returning fluid before again passing it through the Wheel buckets at progressively increasing angles.

3l. In axial iioW elastic fluid turbines, a turbine Wheel provided With a number of annular sets of lapping curved buckets and a series of cast nozzle and return members mounted to coperate Withv said Wheel each of said members being provided With a plurality of injecting nozzles to cooperate With one set of said Wheel buckets and With a number of sets of curved return passages cooperating With succeeding sets of Wheel buckets, oneor more of said sets of return passages being substantially flat and arranged at a greater angle to the adjacent Wheel circumference than the'preceding set to progressively increase the angle at YWhich the motive fluid is injected into the different sets of Wheel buckets. j

32. In axial floW elastic fluid turbines, a turbine Wheel provided With a number of annular sets of lapping curved buckets and a series of return members mounted to cooperate With said Wheel each of said members being provided With a number of sets of curved return passages cooperating With succeeding sets of Wheel buckets, one or more of said sets of return passages being substantially flat and arranged at a greater angle to the adjacent Wheel circumference than the preceding set to progressively increase the angle at which the motive fluid is injected into the diiferent sets of Wheel buckets.

33. In axial flouT elastic fluid turbines, a turbine Wheel provided with a number of annular sets of lapping curved buckets and a series of return members mounted to cooperate with said Wheel each of said menibers being provided with a number of sets of curved return passages cooperating With succeeding sets of Wheel buckets, one or more of said sets of return passages being arranged at a greater angle to the adjacent Wheel circumference than the preceding set to increase the angle at which the motive fluid is injected into the didercnt sets of Wheel buckets.

34. In axial floiv elastic fluid turbines, a turbine Wheel provided with a number of annular sets of lapping curved buckets and a series of return members mounted to cooperate with said Wheel each of said inembers being provided with a number ot sets ot' curved return passages cooperating with succeeding sets of Wheel buckets, one or more ot said sets of return passages being arranged at a greater angle to the acent Wheel circumference than the preceding set to increase the angle at which the motive fiuid is injected into the succeeding` set of Wheel buckets.

35. ln axial flow elastic fluid turbines, a cast turbine Wheel provided with a number of annular series of lapping curved buckets having flat-tened curved bottoms and coperating injecting nozzles and return passages, a number of sets of said buckets making a greater angle to the wheel circumference than the preceding set and one or more of said sets of Wheel buckets having a greater axial Width than the preceding set.

36. 1n axial flow elastic fluid turbines, a turbine Wheel provided with a number of annular series of lapping curved buckets, a set of said buckets making a greater angle to the wheel circumference than the preceding set and one or more of said sets of Wheel buckets having a greater axial Width than the preceding set.

37. ln axial flow elastic fluid turbines, a turbine Wheel provided with a number of annular series of lapping curved buckets, a set of said buckets making a greater angle to the wheel circumference than the gre` ceding set.

3S. ln axial flouv elastic fluid turbines, a turbine Wheel provided with a number of annular sets of lapping curved buckets, a number of sets of said buckets being arranged at a greater angle to the Wheel circumference than a preceding set and a series of return members mounted to cooperate with said Wheel and advancing substantially diagonally across said Wheel, each of said return members being provided with a great-er axial Width and being substantially flat and arranged at a greater angle to the Wheel circumference than the preceding set.

89. ln axial flow elastic fiuid turbines, aV

turbine Wheel provided with a number ot annular sets of lapping curved buckets and a series of return members mounted to cooperate with said Wheel each of said return members being provided Vith a number of sets of curved return passages cooperating with the sets of Wheel buckets, one or more sets of said return passages having greater axial ividti and being arranged at a greater angle to the Wheel circumference than the preceding set.

s0. ln axial fioiv elastic fluid turbines, a turbine ivlieel provided with a number of annular sets of lapping curved bucket-s and a series of return members mounted to cooperate Witli said Wheel each of said return members being provided with a. number ot sets of curved return passages coperating wit-li the sets of Wheel buckets, one or more sets of said return passages being arranged at a greater angle to the wheel circumference than the preceding set.

41. In elastic fluid turbines, a cast Wheel rim :formed of bronze having high co-eflicient of expansion and provided ivitli integrally cast bucket partitions and buckets, a plurality of sets of substantially radial bronze expansion spokes having high coeflicient of expansion secured to said rim, said spokes having ends formed with proj ections to be inclosed and gripped by inwardly projecting lugs cast on said rim, a Wheel hub secured to the inner ends of said expansion spokes, the inner ends of said spokes being provided with projections and said hub being formed of cast ferrous metal of less coefticient of expansion'embracing and gripping said spoke ends and forming integral spoke supports loosely surrounding said spo-kes and allowing their radial expansion, spoke sleeves cast in said spoke supports and guiding said spokes in their radial eXpansion and side plates secured to said rim to inclose said spokes.

42. ln elastic fluid turbines, a cast Wheel rim formed of bronze having high co-etiicient of expansion and provided with integrally cast bucket partitions and buckets, substantially radial bronze expansion spokes having high co-cfficient of expansion secured to said rim, said spokes having ends formed with projections to be inclosed and gripped by inwardly projecting lugs caston said rim, a Wheel hub secured to the inner ends of said expansion spokes, the inner ends of said spokes being provided With projections and said liub being formed of cast ferrous` metal of less co-eiiicient of expansion einbracing and gripping said spoke ends and forming integral spoke supports loosely surrounding said spokes vand allowing their radial expansion, spoke sleeves cast in said spoke supports and guiding said spokes in their radial expansion. a

43. In elastic fluid turbines, a cast wheel rim having high co-eiiicient ofV expansion and provided with integrally cast bucket partitions and buckets, substantially radial expansion spokes having high co-eiiicient of expansion secured to said rim, said spokes fhaving ends formed with projections to be inclosed and gripped by inwardly projecting lugs cast on said rim, a wheel hu-b secured to the inner ends of said expansion spokes, the inner ends of said spokes being provided with projections and said hub being formed of cast metal of less co-elficient of expansion embracing and gripping said spoke ends and forming integral spoke supports loosely surrounding said spokes and allowing their radial expansion.

44. In elastic fluid turbines, a cast wheel rim having high co-eliicient yof expansion and provided with integrally cast bucket partitions and buckets, substantially radial eX- pansion spokes having high co-eiiicient of expansion secured to said rim, said spokes having ends inclosed and gripped by said rim and a wheel hub secured to the inner ends of said expansion spokes, said hub being formed of metal of less co-efficient of eX- pansion and having spoke supports loosely surrounding said spokes and allowing their radial expansion.

45. In elastic fluid turbines, a cast wheel tions and buckets, substantially radial ein pansion spokes having high co-eliicient of expansion secured to said rim, and a wheel hub secured to the inner ends of said eXpansion spokes, said hub being formed of metal of less co-efiicient of expansion and having spoke supports partly surrounding said spokes and allowing their radial expansion.

46. In elastic fluid turbines, a cast wheel rim having high co-eflicient of expansion and provided with integrally cast bucket partitions and buckets, expansion spokes having high co-efiicient of expansion secured to said rim, and a wheel hub secured to the inner ends of said expansion spokes, said hub being formed of metal of less co-eficient of expansion.

47. In elastic fluid turbines, a wheel rim having high co-efhcient ofl expansion and provided with bucket partitions and buckets, substantially radial bronze expansion spokes having high co-efficient of expansion secured to said rim, a wheel hub secured to the inner ends of said expansion spokes, the inner ends of said spokes being provided with projections and said hub being formed of cast ferrous metall of less co-efli'cient of expansion embracing and gripping said inner spoke ends and forming integral spoke supports loosely surrounding said spokes and allowing their radial expansion and spoke sleeves cast in said spokey supports and guidingsaid spokes in their radial' expansion.A

4S. In elastic iuid turbines, a wheel rim having high co-eflicient j of expansion andy provided with bucket partitions and buckets, substantially radial expansion spokes.V have ing high co-eflicient of expansion secured to said rim, a wheel hub secured to the inner ends of said expansion spokes, said hub being formed of cast metal of less cia-efficient ofvveXpansion embracing and gripping said inner spoke ends and forming integral spoke supports loosely surrounding said spokes and allowing their radial expansion, and spoke sleeves cast in said spoke supports and guiding said spokes in their radial expansion. f

4:9. In elastic fluid turbines, a wheel rim having high coefficient of expansion and provided with bucket partitions and buckets, substantially radial expansion spokes having high co-eflicient of expansion secured to said rini, a wheel hub secured to the inner ends of said expansion spokes, said hub being.

formed of cast metal of less co-eflicient of expansion forming integral spoke supports loosely surrounding the inner portions of saidspokes and allowing their radial eX pansion, and spoke sleeves cast in said spoke supports and guiding said spokes in their radial expansion. Y v

50. In elastic fluid turbines, a turbine wheel comprising substantially radial spokes of cuprous metal, a cast wheel riinlhaving substantially the same coeiiicient of eXpansion as said spokes and provided with bucket partitions and buckets and cast around the outer ends of said spokes and a wheel hub of ferrous metal cast around the inner ends of said spokes to effect close engagement and union therewith and allow the original casting strains in said rim to become relieved by cooling the same before connecting said hub there-to.

5l. In elastic fluid turbines, a turbine wheel comprising spokes of wrought cuprous metal, a cast'wheel rim provided with bucket partitions and buckets and castV around the outer ends of said spokes and a Vwheel hub cast around the inner ends of said spokes to effect close engagement and union therewith and allow the original casting strains in said rim to becomeA relieved by cooling the saine before connecting said hub thereto.

52. In elastic fluid turbines, a turbine wheel comprising substantially radial spokes of wrought bronze metal, a cast wheel rim having substantially the same coeflicient of expansion as said spokes and provided with bucket partitions and buckets and cast around theouter ends of said spokes and a Wheel hub of ferrous metal cast around the inner ends of said spokes to effect close engagement and union therewith and allow the original casting strains in said riln to become relieved by cooling the same before connecting said hub thereto.

53. In elastic fluid turbines, a turbine wheel comprising spokes of Wrought metal, a cast Wheel rim provided with bucket partitions and buckets and castaround the outer ends of said spokes and a Wheel hub cast around the inner ends of said spokes to allow` the original casting strains in said rini to become relieved by cooling the 'same before connecting` said hub thereto.

54. lnelastic Huid turbines, a turbine Wheel comprising` spokes, a cast Wheel rim substantially the `same coefcient of expansion as said spokes and provided with bucket partitions and buckets and cast around the outer ends of said spokes and a Wheel hub attached to said spokes to allow the .original casting strains on said rim to become relieved by cooling before connecting said hub thereto.

55. ln elastic fluid turbines, a turbine Wheel comprising spokes, a cast Wheel rim provided lWith bucket partitions and i turbine buckets and cast around portions of said spokes, and a Wheel hub secured to the inner ends of said spokes to allow the original casting strains on said rim to become relieved by cooling the same before connecting. said hub thereto.

56. In elastic iiuid turbines, a cast Wheel rim having high coefficient of expansion and provided with integral bucket partitions and turbine buckets, expansion spokes liaving high coefficient of expansion extending inward from said rim, a Wheel hub cast around the inner ends ofsaid expansion spokes, said hub being formed of cast metal of less coetlicient of expansion.

57. ln axial flow elastic fluid turbines, a turbine wheel provided with a number of annular sets of lapping curved buckets, a series of nozzle and return members mounted to cooperate with said Wheel, each of said members being provided with an in jecting nozzle to cooperate with the first set of Wheel buckets and with a number of sets of curved return passages cooperating with the succeeding sets of Wheel buckets andv advancing substantially diagonally across said Wheel.

58. In axial flow elastic fluid turbines, a turbine Wheel provided with a number of annular sets of lapping curved buckets and a series of return members mounted to cooperate with said Wheel and advancing sub# stantially diagonally across said wheel each of said return members being provided with a number of sets of curved return passages cooperating With the sets of wheel buckets, one or more sets of said return passages being arranged at a greater angle to the Wheel circumference than the preceding set-.L

CHARLES BEMS REARXCK.

lVitnesses:

HARRY L. DUNCAN, Jnssin B. KAY.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of latents, Washington, D. C.