USRE15092E

USRE15092E - baumann

Info

Publication number: USRE15092E
Authority: US
Publication date: 1921-04-26

Description

K. SAUMANN. STEAM TUHBINE.

APPLICATION FILED .IAN.201 I92T.

Reissued Ain-L26, 1921.

15,092. 5 SHEETS-SHEET I.

/far/aumgsgg ATTORNEY K. BAUMANNx STEAM TURHINE.

APPLICATION min Mmm. 1921.

Reissued Apr. 26, 1921.

K. BAUMANN.

STEAM TURBNE.

APPLICATION man JAN. 2o. 192|.

Reissued Apr. 26. 1921.

f'fg.

lar/@maggy "Y Il my K. BAUMANN.

` STEAM TURBINE.

, APPLICATION FILED muze, I92I.

R M Wa /r E Z s. o f 2., x m I M .4h U m w r/ 2 .2 0 5 a I B 1w *I A 4# nu a I 1 42 W DIM, @//m/ L 2 9 1 6., 2 um., A d .HD u n M UNITEDl STATES Pain-:NT OFFICE.

KARL BAUMANN, OF URMSTON. ENGLAND, vASSIGN'OR TOMETROPOLI'TAIN-VICKERS y ELECTRICAL COMPANY, LIMITED, A COMPANY ORGANIZED UNDER THE LAWS 0F GRE'AT BRITAIN.

STEAM-TURBINE.,

Original No. 1,302,282, dated April 29, 1919, Serial No. 105,409, filed June 23, 1916.

l reissue filed January 20,

The invention has for its object to pro? vide an improved turbine oi. this liind in which certain constructional dit? ities inherent in a. turbine of this type are overcome in a novel and l'n-:ictical manner, and the output for a turbine of a given speed. and efficiency is considerably increased.

As is well known, the maximum output which can be obtained -in any given turbine is determined by the' blade area through which the steam leaves the tin'bine proper. This blade area is limited by thel practical diiiiculties which are encountered when blades above a certain length :we used.

In some cases the outlet angle of the blades has been increased in order toobtain the necessary area for the. steam to fiow through. This arrangement, however, impairs the eiciency. of theturbinel The last stage or stages of the turbine Ahai e also been constructed as' a double stage 'or stages, one-half only of the steam acting in each half of the double stage.. In this arrangement the 'steam -in the last stage or stages flows in opposite directions necessi tatlng large and complicated passages for guiding one-half of the steam from the pre ceding stage to one-half of the divided laststage vor stages,'and for leading the exhaust steam to the condenser. With this construction the cost of the turbine is consider ably increased and losses are caused by the formation of eddies in the steam during its `flow through theA guiding passages.

According to the present invention theturbine is so constructed that the steam flow- `ing in substantially .the same direction Speeication of Reissued Letters Patent. Reissued Ahpr, 2.6, 1921,

'Application -for 1921. Serial No. 438,743.

tical effec-t one or more of the rows of both stationary and moving blades or of a row of moving blades in a low pressure stage or stages ot' the turbine, for example, the penultimate and ante-penultiiiiate stages, is or are constructed in lnultipletieis or rings` the individual tiers in a row of 'blades being separated from each other by"circu1nferen tial divirfling walls, so that the steam iiowng through such rowor rows of blades is segre gated into two or more annular portions or helts, the steam flowing through the blades in an outer tier or tiers being expanded. at a greater rateat cach stage (comprz ing a row oi' guide blades or nozzles and its cooperating row or moving blades) than that at which the steam is expanded which flows through the blades or vanes of the adjacentr inner tier or tiers of the same row or rows lying nearer the .turbine shaft'. i

Vith the rows of blades provided with dividing walls as aforesaid, the steam leaving the outer portion of a row of moving blades will insoine cases have'. been fully expanded and passes either direct to the eX- haust or through one or more vfurther rows of moving blades in which its remaining velocity energy is abstracted. The steam 'leaving the adjacent inner portion of the same row of blades will notl have been fully `expanded and may either .be further expanded in a final row or rows of undivided or divided stationary and moving blades from the latter of which it flows to the eX- haust. or may be further segregated into one or more portions in one or more succeeding rows of binding some only or all of which are provided with dividing' walls, the outer portion or belt of steam leaving the Inoving blades of sonie or all of such succeeding row or rows passing direct to the exhaust, tlul inner portion of steam' from thc last divided row oi' blading passing to a final row or rows oi binding in which it is fully expanded and therxfe to the exhaust. It will thus be seen that the steam in au outer tier or tiers is expanded at a greater rate than the steam passing through an inner tier or tiers oi the same row or rows of blades.

The arrangement above described in which the rows of blading are`r provided with tir-` cunifereutial dividing walls so as to form mum efficiency in that tier but with the object of securing the flow of alarge amount of ste-.ini through such inner tier, at the same time -mantaining the mechanical strength necessary to support the outei` tier or tiers of moving blades. This can b e done either b not'expai'uling'the steam far enough to olitain the besteliiciency or by increasing the outlet angle of the binding or in both of these ways.

I have found `that a very satisfactory way of accomplishing the above objects is to ernn ploy blading of the reaction type in one `or more of the tiers and of the impulse type for the other tier or tiers of the same row or rows of biading. For example. for the `iii termediaterows of binding where considerable differences inthe rate of expansion-oi the steam in the varioustiers take piace, I prefer to ilse blading of the reaction type fortlie inner tier or tiers and blading of'tlie impulse type for the outer tiers. Blad-ing of the reaction type may also be adopted for the inner tier or tiers and ot' the impulse type for the outer tier or tiers of the final row .or rows of blades. y

The use of dividing walls which separate the binding of a` row into tiers is.` not re` strieted in its use to the iiiterniediate row or rows of blading, `wlieie the pressure of the steam leaving the blades of the several tiers varies, but may also tor structural reasons be advantageously employed in the final rowy or rows ofghiading where `the pressiire at "which the steam leaving the biadesis substantially uniform over` .the whole of the blade area in such'tinal row orrows.

In somecases it may bedesirabie. to design the binding 'in the inner tier or tiers of the' intermediaterows to torni guide passages only for the steam, the pressure and velocity of the steam heilig substantially vse (i il the same'at the entry and exit ends of Va. stage. In other cases the pressure of the steanimay be reduced and its velocity correspondingly increased Without, however, ab-` stracting any of its energy while passing of the flow of'steam ytakes'place during its-v passage throfngh the statioi'ary blades ot the inner tiers, in` which cases sonic or all ot such liladesinay be. omitted.

The invention iiiay` be carricil into e'cct n in a variety of ways, sonic ot which will now be Idescribed witlrreference `to the aci companying drawings. in which ligures lI and 2 are conventional longitudinal sections' of the upper half of turl'iines of the impulse type constructed in accordance with this invention. Fig. 3 is a parto-f a view similary to those ot' Figs. l and 2, showing the inven-n 'tlon applied to a well known type ot reaction turbine, and alsoA illustrating sections of parts of the binding. Fig; l isa sectional view of a turbine in wliiciil the high pressure. stages are of the reaction type. and in which the low pressure stages are ot' the well known -diskconstruction, the bladiiig being either .ofthe-reaction or `of the ini-pulse type.

Fig.` ,l 'i isni sectional view on an enlarged scale ot' the hladingon the line \''-\v of Fig. 1.

Fig.` (i is a similar view of the blading on the line Vjl-VI' otFig. l. Fig. 7 is a fragmentary reliroduction ofithe last rows' of the blading ot the turbine illustrated in Fig. 2, Figs. H. l), l0 and il being sectional' `views respectively on the lines VIH-VIII, IlX-IX7 XX, XI-XL'of Fig. 7. Fig.

yFigs. l to et. -tionai view hereinafter explained.

througgghl the inner tier or tiers of bladinfr.

1.2 is a sectional view also on an enlarged scaleot' an alternative form of -bladingl which may be adopted in place ofthosc shown in Figs. 9 and i0, or ot' the final row of stationary blades shown in Figs. (i and il. Figs. 13,14 and `i5 are fragmentary views showing in section alternative forms of binding which may be used in'the inner tiers of bladiiig in the turhiiies shown in Fig. 16 is a detail construe` Fig. 17 is a detail view of Figs. 18 and if) sections on the lines XVliI-XVIIL XIXe- XIX respectively ofr Fig. 17 hereinafter explained. Figs. 2l), 2l, 2:2 are enlarged detail -views showing various forms of packingr` which may be employed between the stationary and inovingblades. Fig. 23 `is a fragmentary diagrammatic illustration of another form which a turbine, Vto which .tliepresent invention is applied, may take. Similar parts are indicated by the saniereterence numerals in the various figures of the drawings. 1 y

Referring now to Figi l, the turbinevcylindei is indicated at l and the exhaust casing at 2. vllheturbinc shait is indicated at 3 and the steam inlet at 4. Theeinlet nov# zles" are shown at 5 and the iirst wheel at--G 'i l'irovid'cd with moving blades. 7 as usual.l

Said nozzles and niovinggbladcs comprising the ii rst stage are succeeded by further rows ot' stationary nozzlesa, 8 and moving bladcsf), 9, forming subsequent stages in the uslial way. The row `ofl stationary .blades-10, 1-1 into inner and o vdiaph ra blades 10 and coperatingmoving blades 11 are each provided with a

circumferential wall

12, 13 respectively, whic divide the er portions. This dividing wall may be formed by providing the/blades with lugs or flanges at an intermediate point in their length. The outerportion of the blades 1U, 11, forming the outertier, namely that tier lying far' thest from 'the turbine axis, is designed so as to. expand the steam flowing through it at argreater rate `than thatgtr which the steam flowing through the inner tier of these blades, namely that tier lying nearer the turbine axis', is expanded. The stationary andv moving blades 10, l1 are followed by a further row of stationary blades 14 and cooperating moving blades 15, the former being here shown as consisting of two portions, a main portion 22 and an outlet portion 23. As. illustrated, the stationary blades 14 are supported in position in a 16 which is held in position by means o lugs 17, 18 engaging with a .we

19 extending between the turbine cylinder 1 and a guide-wall 20 in the exhaust casing 2. 'The outer ends of the stationary guide blades 14 in the diaphragm 16 are provided lwith an inclosing wall or rim 21 which separates theI steam passing through the stationary blades 14 from that leaving the outer portions of the moving blades 11.

'17. e operation of the turbine, constructed as above described, is as follows:

The steam admitted through the inlet nozzles 5 flows through the moving blades? and then passes through the several stages t5, 9, 8, 9 and so on in succession in the usual way until it reaches the fixed guide blades 11')'and.moving blades 11 where the steam is divided into two portions by the

circumferential walls

12, 13, the outer portion of steam, namely that flowing through the portions of these blades lying farthestvfrom the turbine axis, being expanded to the pressure in the exhaust. of' the turbine, and passing from the outer portion of the moving blades 1.1 direct into the exhaust casing 2. The inner portion of steam. that flowing through the portions of' the blades 10, 11 lying nearest the turbine axis, only partially expanded and after leaving the inner portions of the moving blades 11 passes through the stationary guide blades 14 and moving blades 15 in which the steam is fully expanded, and after leaving the moving blades 15 also passes direct into the exhaust casing 2 of the turbine.

The steam leaving the inner portions of the stationary and moving blades 10 and 1,1 is thus at a higher pressure than the steam leaving the outer portions of said blades and it is necessary therefore that the clearancespace between the circumferential guide wa1ls-12and 13 and between the cireumf l dirert'ions.

.bla ing fcrential guide wall 13 and the outer rim 21 ofthe diaphragm 16. should be as small as possible. This is best effected by means of a thrust block located as near as possible to the low 'pressure stages and by providing,

the edges'of the circumferential-wall 12 and of the rim 21 with gland strips, several forms of which are hereinafter described and shown in.Figs. Q0, 21 and 22 of the drawings.

f It will be `seen that with a turbine constructed and operating as above described, constituting what may be termed a multiple exhaust turbine, the total area of the moving blades through which the steam leaves the turbine proper is that of the final row of moving blades 15 plusI the area of the outer portion of the moving blades 11.

In this way the desired increased leavingv blade area necessary in order to secure an increased output is obtained without nervessitating the employment of a final roti? of moving blades of inordinately great length or of a divided stage or stages through the blading of which the steam flows in opposite Alternatively, for the same output a smaller blade angle can be utilized for the leaving vstages than with aturbine as heretofore constructed having but a single final row of blades of the same blade height, and thus a better efficiency for the leaving stages, and consequently for the whole turbine, can be obtained.

The energy extracted per unit wei ht of steam in the outer tiers of stationary lades l() and moving blades 11 will be approximately equal to the energy extracted per unit Weight of steam passing throu h the inner tiers of stationary blades 1() an mov` of stationary blades 14 and moving'blades 15. In the construction illustrated, the steam flowing through the inner tiers of stationary blades 10 and movin blades 11 `is expanded at a lower rate t an is the steam flowing through the outer tiers of sta.

tionary blades 10 and moving blades 11, the

remainin expansion of the steam flowing through t ie inner tiersof said blades taking place in the guide blades M and movin blades 15.A The mean peripheral speed o the outer ti of movin blades 11 is considerabl r" ter than t e mean peripheral speed o die moving blades 15, consequently a greater amount of expansioncan eilioiently be utilized in said outer tier; in fact the expansion can be distributed in Suche manner that the efciency of said outer tier may be higher than that ofthe

final stage

14,15. y

Figs. 5 and 6 are sections drawn to an onlar ed scale showing one arrangement of which maybe used in the final stagesY of theturbine illustrated in Fig. 11.

Referringito` Fig. 5, the guide blades-8v and moving blades .9 aswell as the outerv tiers of the blades 10, V11, are of the usual impulse type. In'VFig. 6 'the stationary blades h and moving blades'9 are, of course, fthe samedis the blades 8, 9 in Fig. 5, where- `asthe stationary 'blades 1() and moving blades v11 of the inner tiers of those blades are cfa type specially designed with a. View to 'passing a large quantity of steam through the available blade area, by which terni is meant the totalarea of the complete ring of 'blades measured on a plane'` perpendicular to .the shaft. The inner tiers of the blades.

10, 11 are also designed for a. relatively:I small expansion only of the steam flowing.-

through them, and also with a view .to pro- -viding the moving blades `vvitlrtlie necessary mechanical strength'.` Ir onder that a large quantity of steam ma`r through them the blade anglesiad opted' for "fthe blades of the inner tiers, ar;consider ably greater than the blade anglesadoptedy The 'expansiou`- in they `inner tiers of this stage occurs mainly in the moving blades 11 in which the steam,v

velocity is increascd. beyond that .existing 'f for the outer tiersin then inner tier ofthe guide blades 10, as the space between the moving blades is reduced on account ofthe thickness which it is desirablevto give to the inner-'portions of said blades to afford the necessary mechanical strength. i i

In order to obtain the maximum strength of the blades for a-giveii steam velocity it is necessary yto arrange that-the` expansion shall take place 'chiefly at the entrance of thcpassages betweenthc moving blades l1,

yand that the velocity vshall remain practically constant while the steam is passing through the remaining portions of the pas sages between the blades, the lea'iiiiig angle being arri-.bied as slioivii in Fig. (3 so that the width ofi the remaining portions of the 'y passages between the blades is practically constant. f The final rows of guide blades14 and moving blades 15 are, as slioivn in Fig. G,

-of the usual type as regards the blade an- It is, however, necessary to gles employed. increase th `width of the guide blades 14 and consequently the distancefbctween the moving bladesall and 15, in order to avoid tlieiformation of eddiesand obtain a satis.

factory flow of the steam passing through said guide blades, aswell as to provide the necessary space for the stesi-iii4 leaving the outer tier of moving blades 11. In the construction sliown in 1i and '6; the' guide blades 14 consist of tv'o portions, namely main portions 22 which. in the construction showinare cast in one -piece with .the diaphragm 1G, and outletjportioiis 23,

which are preferably formed separately` and either cast or afterward inserted into a Y passed frame 39 forming .parto'f the diaphragm 16. The stationary blades 14 need not, however, necessarily be' constructed in two portions, as shown in Fig. 6, but may be formed as slioivn in section in Fig. 12, iii one piece.

. In some cases, in 'order to provide the nec-` essary strength the movin blades 11 and the `final roWof movingikb ades V15y may be made to taper in Width asshovvn in Fig. 1, or in thickness, or in both o'these dimensions along the Whole ora portion of their length, increasingv in section toward thel root of the blades. Advantageonsly these blades may be constructed as described 'in the specitic-ation of British Patent No. 14,051 of Oc- 4tober 4th, 1915.

VAlternative designs for the inner tiers of stationary blades 10r and moving blades 11 -slioivnhin Fig. 6, which in certaincasesA ,may be adopted, are yillustrated'in Figs. 13, 14: and 15.y

Fig. 13 shows a de "en in -wliich the oiitlet angle of the guide blades 1() is' smaller than in Fig. Gand is such that having regard to the velocity of the moving blades 11,relativeto that ott-he guide blades 10, the steam enters said moving blades in an approximately axial direction. In this design' a` relatively greater partl of the expansion occurs in tlieguide blades 1() than in the corres r)onding guide blades 10 shown in HFigIG." rlhe inlet portions of the moving blades 11 are reduced to an edge vas showin,

so as to prevent eddies where the steam meets the edges of the blades. The expair sion through the moving. blades 1l .takes -place chiefly atl the inlet portion of the moving blades y,1170i Fig. 13,.the lleaving i angle being arranged shown so-that the width of the remainder of the passage be- Jv,tween the blades remains practically con- Stai'it.

In the design shown in Fig. 14 no change in the direction of the steam takes place Iduring its passagel through the guide blades 10. Y

The blades can, as shown, be flat and located in a plane parallel withA the axis 'of the turbine, or they may be inclined iii either `direction withv respect to the turbine axis.

As no appreciable `bange in the direction of the `steam takes p ace some or all of the blades 10 `may beomitted. If these blades are omitted the velocity of the steam may be varied as desired either by decreasing or by increasing the-radial height of the passage.- If the inner tier `.of guide blades is omitted soine means for directing the steam flowing from one row' of moving blades to the next, to take the .ilace of the inner circumferential wall of the guide passages,

' Lapseare designed in such .a manner that no eit-A pansion of the steam during its passage through them takes place and the direction of the steam leaving is the same as the direction' of the steam entering the blades, no mechanical energy being abstracted from the steam'du'ring its passage through them, and lconsequently no appreciable change in its pressure occurs. The moving blades 1] are of an f shape, as shown, the centralportion being straight and of uniform thickness, and the sides reduced to an edge so, that the steam passage between two adjacent blades is of practically con-I Stant width. .This design enables blades of the necessary mechanical strength to be pro- "ided which do Anot'chan e the velocity vof the steam to any extent uring its passage betweenv them.

The lguide blades shown in Fig. 15 are of the same type as those shown in Fig. 14. The moving blades 11 are flat and more or less.inclined'relative to the axis of the turbine, being reduced to a fine edge at bot-h sides, especially at thel outlet side, the center portion of the blades being preferably'r of substantially uniform thickness.

. A passage is thus formed between adjacent blades -in which the pressure ofthe steam is reduced at the entrance of the blades and the velocityr increased as it flows toward the middle portion of the passage the vclocity being reconverted into pressure byj `final row may take. described ab'ove with reference to Figs. 5, 6, 12. 13, 14- and 15, havebcen given by way ot' example and as indicating some otl the iuore advantageous designs which can be employed. The blading ot the circuniferentially 'divided tiers niav sometimes be ol' thel same character in.

two or more of the individu-.il tiers of a row. The expansion however taking place at difl'rrent rates'in l'lie'several tieis of a row. `The blades may in some cases also have the same inlet and outlet angles in the various tici-s ot' a row. Frequently also it ywill be fiiund advisabh` to provide an outer tier of a row with a greater number o f blades vthan an inner tier of thc same row.

Fig. 1G shows a modified form which the outer inclosing wall of the stationary blades may, with advantage, assume. The' outer wall or rim 21 is here shaped so as to change -tlie direction loff the steam leaving` the outer tier of the moving blades 11 from a substan-` tially axial into a substantially radial direcl 'tion during its passage to the exhaust casing. In order to prevent, as far as possible, the formation of eddies, due to the rapid change of direction of the Steam, an additional guide 24 may be provided which will separate the steam flowing to the exhaust into two 'portions. More than one of such additional guides may of course be used if desired, and they need not necessarily be su ported from the inclosing rim 21, as here illiistrated` but may be attached to the' turbine cylinderor exhaust casing. One oi" more simliar guides to that shown at 24 in Fig. 16 may be provided for directing the steam leaving the last row of. moving blades 15. The shape given -to the inclosing rim 21 and curved guide 24 will obviously depend upon the direction in which it is desiredthe steam leaving the moving blades should flow toward the exhaust, as the change in the flow of the steam need notnecessarily be from an axial into a radial direction. l l

Fig. 17 shows a further modified construc- Ation' oi the final guide blades 14 and moving bladesl. an additional circumferentialdividing wall 25 being provided extending ,over a part or the whole width of the guideY blades 1l and corresponding dividing wall` 2G separating the moving blades 15 into the inner andouter tiers. The stationary .and moving blr desfof the outer tiers are again of the impulse type and those of the inner tiers are of the `reaction type. The blades of the inner and outer tiers are respectively shown in section in Figs. 18 and 19. these fiifures being taken on the lines XVIII-X vIll', XIX-XIX of Fig. 17. This combined use of impulse and reaction blading in one and the same row is, in some cases, also adapted to obtain the best efficiency for the last stage of the turbine'. as well as mechanical strength for the roots of the moving blades, blading of thi` reaction type. being more suitable for the inner tier owing to the relatively higher steam velocitiesobtained in the passages between the moving blades which enables the i'oots of the moving blades to be made arise ldue to the great 'dilerence in steam velocitiesresulting'from the great difference in the peripheral velocities between the inner and the outer tier.

Iig. shows on an enlarged scale"v the type ofvpacking shown in Fig. 1 as being' i used between the circumferential dividing 'walls ot' the `stationary rfid moving blades` 10, ll .and between the moving blades 1l and the inclosing wall 21 of the stationary blades 14'.. As shown in this figure the side of the circumferential wall 12 adjoining the circumferential wall 13 is sharpened to a. knife edge so as to reducethe daiigcr'of heating in case rubbing takes

place between'tlie walls

12 and 13. The nclosing rim 2l is shown as being provided with a gland strip 27 of a well known type `for a similar reason.

Fig. 21 shows an alternative form of pack? .the same. direction as the working steam Y' passing through theftiirlgi'ine.V The `direction volumes of Asteam. through ,the low pressure ,stream lines.

in which any leakage steatn willhejcaiised to How with` -the arrangement showrfijzin this figure is indicated.diagrammatically bythe Referring now d l v struction which may be adopted nin .those cases wherey it is necessary to .pass greater' stages of the yturbine than in the case of the vturbine describedy with refereneelto Fig. 1. i In other words, tor similar steam yconditions and eicieneies the outputof the turbine can, with this construetion, lbe considerably ini creased. ln the turbine shown in Fig. 2 the i at steam flowing through the innerv tiers ot'.V the circumferentially Hdivided stationary i and moving `blades 10, 11 'is further segregated by eirr-,iimferential division walls 31, -32 in the succeeding stage comprising a row of fixedbladesi andmovi'ng blades 34. The steam passing, through the outer tier of the stationary; and movingV blades 33; 34 is expanded .down tothe pressure inthe Vexhaust to which it directlyowson leaving the outer `panding at a low rate duringvits passage through the inner tiers'ot the stationary and

movingblarles

33,34 is again segregated into `two portions by`

circumferential dividing walls

35, 36 in a further succeeding stage comprising stationaryiind movingblades in` dieated at 37,`38,respect ively. l"llie'fstcain ai Fig-,2, aus Siiws a et passing through the outertier of the station` aiv and moving blades 3T, 88 isrexpanded down to the pressure of the. exhaust and on` leaving the outer `tier ot' moving blades 3S passes direct into the exhaust casing 2. The .energyY remaining in the steam ai'ter flowing tliroiiglithe inner tier of the stationary and moving blades 3T. 3S iii wliicliit is expanded ata low rate is utilized in a final stage eom, prising" stationary blades 14 and moving blades 15 in a manner already describedwithv reference to Figi; j

It will `be seen that iii a turbine constructed as shown in Fig. 2 the total blade area 'through which the steam leaves the turbine proper is aiiproxiniately increaseul` by the blade areas of the outer tiers of the mov ing bladesl and 38' ascompared with' the construction illustrated in fFig.A 1.

()ne arrangement ot b lading which may be adopted `in a turbine ot' thc kind illustrated in Fig. .2 is shown for example in Figs.` T to 1l. inclusive. Fig. T it will he seen is a reproduction of some ofgtlie low pressure stages of Fig. 2 and Figs. 8. 9, 10 and 1"l are'sections ofthe blading in Fi 7 taken respectively on the lines VIII-VFIL IX-lX, X--X and XL-XL The maiiiier in which the'tui'binedescribed and illustrated iu Figs. T. B. 9, 10 and l1 operates will be readily understood from what has been lsaid in connection with Figs. `il, 5, 6 and 12-` it being understood that intlie `turbine illustrated in Figs. 2, 'i'. 8, 94, 1()

and 11 also various alternative designs and eombinationsoi bladng may --be, 'used las liereinbefore fullyset forth.

One: example ofliow the invention may he applied to a turbine inwliicli the whole of Vthe binding is of the raction typedsilliis trated ilu Fig. 3. the construction and operation of \\'liicli.iaken in conjunction with` the sectional views of the bladin'g in the low l )ressure stagcson thelinesl-l. ll-Jl and and designated b v vthese.numerals respectively. wi'll be easily .comprehended 'without further detailed' description.

Fig. 4 illustrates still another form of. turbine constructei'l'in accordance. 4with this invention in which the high pressure stages are of the usual Vreaction type and the low pressure stages are 'of the well `known disk construction. "the bliiding being of either the impulse 'or reaction type or a combination' of these types.`

In tlieconstrnction illustrated in Figs. 1,

2" and 4 the 'moving blades of the low presd sure. stages are vshown as being `attached to separate disks mounted on the shaft 3. In some cases itI is preferubleto attacl'i some or all of such moving blades directly to the shaft itself. the shaft `in, such cases bein increased iii diameter iand^`"provided .wit i Hai'igcs or colla rs vto whicli'tlie moving blades are secured iu any suitable way. ln thesetik a iris figuresalso a single .exhaust casing only is shown into which the steam leaving the several rows of moving bladespasses. It is Vto be.understood however that the steam leaving the various rows of moving'blades ma)v pass to separateexhaust casings and in some cases to separate condensers. ifn desired.

A still further constrnctional form which the invention may take is shown diagrammatically in Fig. 23. In the turbine dia rammatically indicated in this figure it will be seen that the segregated annular portions of steam each flow through a plurality of rows of fixed and moving blades before reaching the pressure of the exhaust and iassing to the exhaust casing of the turbine. t will also be observed that in one row-of stationary and moving blades the steam is segregated into threeannnlar portions, the stationary and moving blades in question being constructed as a triple tier. The blading may be arranged in such a way that the ratio of the steam velocities andperipheral velocities obtaining in the various tiers is apl'i'roximatel)` constant, thus ,obtaining a uniform elliciency -over the whole of the various. noirs of blades.

From the examples hereinabove described and illustrated it will be evident that the steani flowing through the working passages of a tibine constructed in accordance with this invention is dividedinto separate por- "ftions forming more or lesscomplete and turbine.

partially overlapping belts of steam, the ontermost belt or belts while passing through theoperative bflading of the turbine being expanded at a greater rate than the. inner belt or belts lying nearer the axis .ofthe The steam in the outer belt or belts is let away separately to the exhaust immediately it has been expanded to the full extent. and its velocity energy abstracted therefrom. M V

Stated in other-words the belts of steam flowing through the turbine. while in operation may he likened to a plurality of trillicated hollow cones. the steam forming the smaller end of the second and any succeeding concs being derived from the steam of the preceding cone. At the, base vot each of such cones the Steam will' have been fully expanded 'and conducted away to the exhaust. Thus the steam will be led away to the exhaust from a plurality of independent rows of moving blades. v

As hereinabove set' forth turbines of either the impulse or reaction type, or a combina tion of those types. may be constructed in accordance with this `invention and although the invention is an improvement in turbines of the axial flow type it is to be understood that. the high pressure oir other sections of the nrbine to which the invention is not a plied may. if desired be of any other suit a le type. The;` invention is especially apexhaust.

2. In a turbine having a single exhaust. a 100' portions of the steam flow in opposite directions to the exhaust. In short, the invention may be applied to axial flow steam turbines of many of the various existing types adapted t0 operate at a high vacuum in which, as heretofore constructed, in order to* obtain a large output, blades of inordinately great length would have to be used.

In the modifications illustrated it will be seen that the low-pressure motive fluid is segregated into a plurality of portions which discharge through successive rows of blading.' In this way, the leaving blade'area in the low-pressure part of they turbine may beblincreased to an extent heretofore impos- Sl e. l

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be per-y formed, I declare that what I claim is:

1.' In a turbine, the combination of a 'plu. ralitv of successively arranged stages having the motive Huid passing therethrough in approximately the saine direction including rows of moving .blades and means tn Aincrease the leading blade area including means to discharge steam from-a plurality of said rows of moving blades directly to the low-pressure part having the steam Howing therethrough in substantially the same direction including a plurality of successively. arranged rows of moving blades and means .whereby steam flows from each row of moving blades directly to the exhaust.

3. A. fluidl turbine of the axial flow type in which the steam flows substantially in tha` same direction throughoutincluding a lowpress'ure part and means associated with the 110 low-pressure part for segregatng the fluid into a plurality of Iannular portions and for expanding the portions at different rates, the portions passing from the plurality of rows of moving blades vto the exhaust.

4. In a turbine. a low-pressure part includ# ing means for passing the motive fiuid thel` through in annular portions and in approxi..

-mately the same direction, the range of exv 5. In a turbine having a high-pressure 125. part and a low-pressure art, the'low pressure part including a. p umlity ofjsucsblades' and rged from sively arranged rows of movi means to divide the steamedisc the high-pressure parinto a plurality of 130 Y abstracted from each ofthe annular portions.

Jia

portions, energy from each portion beingiabstracted by a separate row of blades and all of theannular portions .fdnliarging to 'a common exhaust chamber.

6. In a turbine having a high-pressure part and a low-pressure, part, the low-pressure part including aplurality of successively arranged rows of movin yblades and means to -divide the motive uid flowing from the 'high-pressure part into arplurality of annular ortions or belts flowing approxi mately in' t e same direction, energy being or belts b a separate row of moving 'blades and all o the annular portions or belts disf charging into a eommonexhaust chamber.

7. In a turbine, the combination of a low pressure part including a plurality of rows of blades'and means for dividing" me of the rows into inner and outer tierii and for segregating'the steam passing therethrough into inner and outer portions, the inner portion or portions'passing tothe exhaust througha greater nuinber vof rows than the outer portion or portions.

8.l I'n afturbine, a low-pressure part havingthe steam,passing tlierethrou h in approximately thesame-direction inc uding inner tier blading, outer tier blading, and last row blading, the motive fluid being expand- `ed mainly in the Vouter tier and last row blading and the inner tier blading serving to' discharge motive fluid into said high expension b ading. n

9. In a turb'ne, a 4 low-pressure' section comprising one or more successively arranged stages including super moving blades, adapted to divide the motive fluid into a lurality of annular portions or belts and a sti-act energy from the lpelts` passing therethrough2 and other stage" or stages,

the inner portion or portionslof the lsuperpoaed blading adaptedtoy pass steam to said other stage or stages.

il). In a turbine, a low-pressure part coml prising a plurality ofsuccessivelyr arranged rows ofv stationary and'lmoving blades, and means associated with said blades to divide the steam vinto successive annular ortions or belts for passage through successive rows off moving blades to the exhaust. i

11. In an axial flow turbine, a low-pressure part including a plurality of rows of stationary and" moving blades arranged in succession and "means associated :with one or more of the rows of bladesf'to Isegregate "the steam passing ytherethrough into a plurality of' annular` portions or belts which pass directly from `the moving rows of blades to the exhaust. y, 12. In a turbine, a low-pressure part hav- "ingthe motive fluid passing therethrough in substantially the same direction, a pair of rowsfof 'stationary and moving blades,

y means lto ydivide the motive fluid into inner` osed rows of and outer annular portions for `passage through the moving blades, a row of stationary blades receivingthe inner annular ortion of motive fluid, a shroud carriedby the latter blades and cooperating with the turbine `casing to define :in exhaust for the i outer annular portion of motive fluid, said last-named 'blades being sufficiently wideto provide an adequate exhaust.' 1

13. JIn a fluid turbine, a low-pressure.part including a lurality of stages inv which the motive fluid) flows in approximately the same direction and means associated `with one or more of said stages to` divide it or i vthem into inner and outer tiers and to segregate motive fluid passing i therethrough into a plurality of annular portions or belts,

the. annular portion or portions passingw through some tier or ti s being` expanded lat a greater rate than t e annular portion or portions passing through the outer tier or tiers and the 4annular portions or belts passing Ifrom the moving rows ofbladesv of said stagesdirectly to the exhaust.

14. In anfaxial flow fluid turbine, a lowpressure part'including a pluralityv of stages in which the fluid vflowsy in Substantially the same. direction, circumferential wall or walls 4associated with the stage or stages to' divide the stage or stages .into inner and outer.I tiers and to segregatetlie motive fluid passing therethrough into al plurality of annular .portions or belts, the annular portion orV portions-passing through theouter tier or, .tiers being expanded at a greater rate than the annular portion or portions exhaust frq said. stages,i y. 15.'1n a turbine, a low-pressure part hav# ing the'mtive fluid` passing therethrough in approximately the same' direction including a plurality of rows of moving `blades and means Yfor dividing one or more of said rows into inner and outer tiers, the motive fluid being expanded at different ratesin the innerV and outertiers and passing from precedin innertiersto succeeding outer tiers ya another row of moving blades.

In the moving rows of blades of ing motive fluid passing therethrough in approximately the same direction including moving rows of blades and means associated'fwith' one 0r more of said rows of blades. 'to divide kit or them intoinner and passing through the inner tier or tiers andy the annular portions passing directly to the iis 16. In a turbine, a low-pressure part havouter portions and to segregate the motive;`

lfluid into annular portions,

expanding in one blade1 rtion ata greater rate than in another an all ofthe annular the motive fluid i portions of motive fluid being expanded to. exhaust pressure upon. discharge,fromA the 1 moving rows ofblades. i

17. In afluid turbine', a low-pressurepart having steam` flowingjwtherethrough injl sub#` stantially the same direction and including a plurality of rows of stationary and' moving blades, .one or morecircumferential dividing walls associated with oneor more of 5 said rows of blades for dividing them into inner and outer tiers and segregating the steam Ainto two or more annular portions or belts, the outer tier or tiers adapted to expand steam at a. reaterrate than'l the inner 10.ti er or tiers, an said annular portions or vbelts passing from a plurality of moving blades tothe exhaust. 51x18.I In a fluid turbine, a low-pressure part jpeluding a plurality of rows of stationary l'ifgid moving blades and ymeans associated ,"fwith one or more of said rows of blades to di-Yide it or them -into inner and outer tiers and' to segregate the motive fluid passing 'therethrough into a plurality of annular 2Q portions, the annular portions passing through the outer tier or tiers being expanded at a greater rate than the annular lportions tiers, an all of the annular portions discharging 'from the rows of moving blades ditectl to the exhaust.

-19. n a fluid turbine, a low-pressure part including a plurality of rows of stationary and movmgblades and circumferential walls eo atin with a plurality of rows of said bla esto ivide the latter into inner and outer tiers and to .segregate the motive fluid passing therethrough into a plurality of an nular portionsor belts, the blades of an outer having the outlet angles thereofdess than gl" theoutlet `angles of the blades of an inner whereby the `motive fluid 'will be ex- Plnded at a greater rate inthe outer tier .i than in the inner tier, and the annular porloztins'or belts passngffrom the moving rows 'i blades directly to the exhaust. i n 20'. In a fluid turbine, a low-pressure part having' the steam assing therethrough in "',Stlbtantiall the saihe direction including a luralityo rows of stationary and moving i lades and`circumferentia1 walls associated with a lurality of rows of said blades to ,divide t ern into inner and outer vtiers and :lo segregate the motive fluid passing there- .Q0 through into a plurality ofannular ortions,

the blades of an outer tier being ci) the im- "ulse ty e and the'blades of an inner tier o the reaction type whereby` motive will be expanded at a greater rate`in the 5 5 outer tier than'in the inner tier and the annular portions or belts of motive fluid .passing from the moving rows of blades directly to the exhaust. 'i i 21.111 a fluid turbine, a low-pressure part having steam flowing therethrough in substantially the same direction and comprising i a plurality of rows of stationary and moving blades, 'means for dividingone or moreof. said rows into multiple tiersandfor gating the therethrough dpassing through the inner tier or a plurality of annular portions, the blading i including a pluralitybf rows of stationary' and moving blades passing motive fluid iu substantially the s'ame direction, means associated with said rows of stationary and moving blades to divide the latter into inner and outer tiers and to segregate thesteam passing therethrough into inner and outer 'annular portions or belts, and a last pair of `rows of stationary and moving blades receiving steam from an inner tier, the steam expanding in said outer tier or tiers and in said last pair of rows being'at a dillerent rate than in the inner tiers.

23. A steam turbine vcomprising a casing, a rotor, one or more stages or sections carried thereby, a pair of rows of stationary and moving blades carried thereby and receiving steam from the last of said stages, wall ele ments associated with the stationary and moving blades to divide the latter into inner-` and outer tiers rind Vto segregate the steam .into inner and outer belts, thc outer tier of stationary and ymoving blades adapted to cxpand and abstract energy lrom the outer steam belt, and a second pair ot' rows ot stationary aiid moving blades carried by the rotor and casing and adaptedto receive steam from the inner tier, the expansion of the outer steam belt in the outer tier being approximately equivalent to the expansion ot' the inner belt in the inner tier and in the second pair of rows of blading'.

24. In a -fluid turbine, a low-pressure part. including a plurality of rows of .stationary andxnoving blades passing motive fluid in substantially the saine direction, Incansassoi,

ciated With said rows of stationary and mov-i ing blades todividc the latter into inner and Vouter tiers and to segregate the steampassing therethrough into inner and outerI annular portions or belts, and a last pair of rows of stationary and moving blades receiving steam from an inner tier, the steanrexpanding. in said outer tier or tiers and in said last pair of rows being at a different rate than in the inner tiers, the moving blades boing tapered from the roots toward the tips to providel blading Structure of relatively great radius and sullicient strength.

25. In a fluid turbine, a hiw-prcssure part including a plurality of 'rows of stationary ,and moving blades 'passing motive fluid in Substantially the same direction, means associated with said rows of stationary and movblades to divide the latter into `inner and outer tiers'and to segregate the steam passing therethrough into inner and outer annular portions or belts. and a .last'pair of rows of stationary 'and moving blade sur..

last pair ot' rows beingr at afditferent rate than ln the inner tiers. all ot' the moving blades being tapered in thlrknessfrom the roots toward the tips whereby relatively longV and adequately strong blades may be provided.

26. ln a Huid turbine. a'low-pressure part including a plurality of rows ot' Stationary and moving blades passing motive fluid in substantially the same direetion. means assoeiated with said rows oti stationary and moving blades to divide the latter into inner and outer tiers and to segregate the steam passing therethrough into inner and' outer annular portions or belts` and a last pair of rows of stationaryand moving blades receiving-steam t'roni an inner tier,

the steam expanding in said outer tier or,

4 ner and outer tiersi. and to segregate the steam passingtherethrough into inner and "outer :mnularioortions or belts. and a last air of rows of stationary and moving liledesv receiving steam `from an inner tier.V thetsteam expanding in said outer tier or tiers and in said last pair ot' rows being at a different rate than in theinner tiers. all of i the moving blades being tapered in thick;

nesse`1`1d'ln width from the roots toward the tips Iwhereby relatively long!` and adequately outer tiers. and to segregate the steam into* a plurality of annular portions or belts, the outer tiers of a movingvrow of blades adaptedito abstract energy from an annular or tion andthe inner tier comprising b ado portions having their entryfedgs ta ered whereby motive fluid is expanded whi e en tering between the blade portions and the remaining portions of the blades defining l passages of vapproximately constant width curved at the leaving'edges in order to seivng steam from :in inner tier. the steam expanding in said outer tier or tiers and in said and adequatelystrrmg blades ing therethrough in'toannnlar portions. the outer tier blading designed toA fully expand annular ,portions passing therethrough and the inner tier blading adapted to pass steam to succeeding outer q tier bladingr and a last pair of stationary` and moving blades with little loss in energy s0 romprising stationary blade portions having large outlet angles and moving blade portions having their entrance -edgestapered to define entrance steam expanding passages and the remaining portions there# S5 of defining 4passages of approximately conlstant width curved at the discharge edges Y in order to secure' diseharge of steam in desired direction.

30. ln aturbine` a low-pressurev part com? prising a plurality ot rows of st'tionary and moving blades and means to. divideone or more ot' the rows into inner and outer tiers and to segregate the steam passing."

-therethrough into a plurality of annular portions. an outer tier adapted to abstract energy from an annular yportion and dis" charge the latter at exhaust pressure and an inner tier serving as a bv-pass for an inner portion whereby a .support for outer tier is L00- provided. v

.31. ln a turbine. a. low-pressure piirt. having motive fluidv passing therethroughin approximately the same direetion int-hubA ing a'plurality of rows ot' moving blades 105 and ymeans for dividing one or more of said rows into inner and outer tiers. the inner tier serving to pass motive Huid withlittle loss in energy to succeeding outer tiers and another row of moving bladesthe motive' 11o Huid being fully expanded in nalned tiers and blades. v 32. In a turbine, a vl`o-w -pressure part `ineluding a 'plurality of'rowsgof' stationary and movingfblades', means em'iperating with 115 some of said bladestodivide the steam vpass'- y.

ortions'. o .5 belts, the outer portions of t e moving said lastblades serving to abstract energy from some of said belts' and the inner portions servinl 120 to guide some of said belts to suceeeding outer portions, and .rows of blades to abstract 'energy from last and innerbelt 33. In a turbine, the combinatibnvwith elements supported by the casing, the wall elements constituting walls cooperating to segregate the steam into belts for the moving blades of the low-pressure stages.

^ 54. A steam turbine comprising a casing, a rotor, one or more stages carried by the casing androtor, a pair of rows of stationary and moving blades receiving steam from the last of said stages, wall elements for dividing the blades into inner and outer tiers for inner and outer portions of steam, a stationary row of blades supported by the casing and receiving steam from the inner tier, a wall element carried by the tips of said last-named stationary blades, the wall elements coperating to constitute a wall to segregate the steam into innerand outer portions, the outer tier of said moving blades'abstracting energy from the outer portion `of steam, and a row of moving blades coprating with the last-named stationary blades for abstracting energy from the inner portion of steam.

flngi steam turbine having a casing and rotor, a low-pressure section including a plurality ofrows of stationary and moving blades, wall elements for dividing the blades into inner and outer tiers for inner and outer Aortions of steam, a diaphragm supported liy the low-pressure end of the casing, a stationary row of blades supported by the diaphragm and receving steam from the inner tier, a Wall element carried by the tips of said last-named stationary blades, the wall elements cooperating to constitute a wall to segregate the steam into inner and outer portions, the outer tier of' said moving blades abstracting energy from the`outer portion of steam, and a row of moving bladescoperating with the lastnamed stationary blades for abstractiiig energy from the inner portion of steam.

' 36. A turbine comprising a casing provided with an enlarged low-pressure end, a rotor, a series of stages carried by the casing and rotor, means for-segregating the steam discharged fromthe last stage of said series into a plurality of belts or portions comprising wall elements, web elements connecting the Wall elements together and to the interior ot the low pressure end of the casing. stationary blades connected to the casing and web elements, moving olades cooperating with the stationary bl ides and carried by the rotor, andwall eler ents carried by some of said pairs ot blades, the wall elements carried by the ends of some of said stationary blades, the wall elements of the pairs oit blades, the ends of the blades, and the first mentioned wall elements defining walls for the passage of belts of steam,and moving blade elements in` each belt to abstract energy therefrom.

nular portions, said annular portions pass` ing to the exhaust from a plurality of' moving blades, and meansassociated with the final blades to divide them into portions having different blade outlet angles.

38. In an axial flow turbine, a low-pressure part having the motive fluid passing therethrough divided into a plurality of annular portions including ont` or more wall elements to change the direction ol' flow of one or more of said annular portions 'from approximately an axial to aplnoximately a radial direction and means cooperating therewith to reduce eddy effects.

39. In an axial flow turbine, a low-pressure part having the motive fluid passing therethrough divided into a plurality ot' annular portions including one or more wall elements to change the direction of' flow of one or more of said annular portions from approximately an axial to approximately a radial direction and a circumferential guide cooperating therewith to reduce eddy effects.

40. In an axial flow steam turbine. a stage or section provided with means for dividingr the steam flowing therethrough into annular portions having different ratios of expansion.

41. In an axial flow steam turbine, a stage or section provided with blading structures so arrangedas to segregate the steam into separate concentric annular portions having different expansion ratios.

42. In an axial flow steam turbine, a stage or section having blades constructed in nmltiple tiers and ai'rangcd so that the steam flowing through the different tiers will have different ratios of expansion.

43. In an axial flowstcam turbine, a lowpressure stage or section provided with blading means formed so as to segregate the steam flowing through said stage or section into separate portions having different expansion ratios.

44:. In an axial flow steam turbine, ahigh pressure stage or section thi-ou rh'which the steam flows in one annular bo y and a 10W pressure stagev or section through which the steam flows in two or more .annular bodies having different ratios of-expansion.

45. In an axial flow steam turbine, a stage or section having blades constructed in multiple tiers formed so that the steam flowing through the outer tier hasa greater ratio of expansion than the steam flowing through the inner tier.

46. In an axial flow steam turbine, a. stage or section provided with means for segregatiiugr the stealp owing therethrough into separate portions having different ratios of oxpaasibli;y

X17; 1'n\an\axial flow steam turbine, a stage or section having superposed concentric rags of blades so formed that the rings of blades farther from the `turbine axis have out et angles different from those of the rings`of blades nearer the turbine axis.

48. In an axial flow steam turbine7 a parytial peripheral adniisign high pressure stage and a fall peripheral admission 10W- pressnre stage provided with h'ieans for segregating the steam flowing therethrough into portions having different ratios of expansion. 1

Signedat Manchester th'l` 1"th day of December, 1920.

KARL BAUMANN.