US2102637A - Arrangement of radially traversed blades in rotary machines - Google Patents

Description

21, 1937.- u` MEININGHAUS 2,102,637

'ARRNGEMENT OF'V RADALLY TRAVERSED BLADES N ROTARY MACHINES Filed May 17, 1935 6 Sheets-Sheet 1 l W ,u

k r f va Hrm/mfr Dc. '21', 1937'. U. MEININGHAUS v 2,102,637

ARRANGEMENT OF RADIALLY THAVERSED BLADES IN ROTARY MACHINES Filed May x7, 1955 6 sheets-sheet 5 Fig 3 m f :ELi ,2

dz, 5- o a S IMI Y d w m 1.." I` Y a l 2- 6 i, 6 m III/ /III/l IIIII 6 3. la y9 23 fr* 8 l/rwfrfrolil l21,. 1937. U MEININGHAUS Y 2,102,637

ARRANGEMENT OF RADIALLY TRAVERSED BLADES IN ROTARY MACHINES Dec. 21, 1937. u. MEININGHAUS 102,631

AARRANGEMENT OF'l RADIALILYl TRAVERSED BLADES IN ROTARY MACHINES v'Filed May 17, 19253 6 vSheets-Sheet 5 Dec- 21, 1931- U. MEININGHAUS 2,102,637

- RRANGEMENT OF-RADILLY TRAVERSED BLADES IN ROTARY MACHINES 6 Sheets-Sheet Filed May 1'?,` 19:53

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/M nr B KMF/ 'Paie-mcd Dec. g1, 1931 UNITED s'iisxri'is My invention relates to rotary machines such as steam or gasturbines in which 'a working medium ows through aplurality of blades yin a radial direction, varying in pressure during such iiow. 'I'he object of the present invention is to' diminish the total axial thrust created by the variation of pressure with which the working mediumacts on radially extended surfaces and at `the same time to improve the conditions of Vilow.

It is known that in rotary machines provided with reaction blading large axial thrusts occur which are generally equalized by subjecting an equalizing pistn provided with packing to an .Y

oppositely directed pressure of the working medium. As the packings of the equalizing piston must-be arranged on a large diameter in order to expose suihcient piston surface to the pressure the packing loss, which is at least proportionaly to the packing diameter, is large. In the con- I chine is, therefore, lengthened. On the other hand, a construction of the shaft with small blading diameters does not permit of great length oi A the shaft in view of oscillations, in particular in view cf critical speeds cf rotation. Extension and thinning of the shaft, therefore, have an unfavourable effect. A limit isfthus very soon reached 'in applying these known means for reducing clearance losses of the equallzing pistoni In cases of rotary machines with multiple housings the additional losses of the equalizing piston have been successfully avoided by letting the medium traverse the several housings in op` posite directions', the now oppositely directed thrusts on the shaft being determined in such practically counterbalance one.

l a way that they another.

'Ihe absolute thrusts on the '-shafts remain, however, large. Even small variations from the calculated values give rise to considerable differences in thmst which must be taken up by the thrust bearing and may destroy it. In particular,.

the thrusts exerted on the shaft change to difterent degrees when overloads occur, or when some aimerail ARRANGEMENT 0F RADIALLY `rIRAVERSED BLADES IN ROTARY MACHINES Ulrich lVI-eininghaus, Mnlheim-Ruhr, Germany f Appiicaticn May 17, 1933. scr'ici Nc. 611,442

- In Germany June 1, 1932 .15 claims. 4 (C1. 253-19) PATENT loF'r'lcF.

of the working medium is tapped off. If the absolute axial thrusts exerted on the shafts are considerable, such. large difference in the oppositely directed thrusts may arise in such cases that the thrust bearing can no longer withstand them or at least is likely to be endangered. Fur. thermore, such an arrangement involves large demands in space and high costs in manufacture.

Stilllmoreunfavorable was the position in regard to the previously proposed constructions of radially traversed rotary machines. In order to obtain as simple a construction as possible or in order to allow the ,diameter of the blading to increase progressively in accordance with the expansion of the working medium during the flow through the rotary machine, it was attempted to arrange the blades on as few discs as possible as far as was permissible in viewof the avoid'- 'ance of overloading, by centrifugal force, of the double housing was'applied. one disc for each of the opposed housings. the discs carrying the blading were inbthis way large, and, therefore, the axial thrust assumed non-permissible values. The above described disadvantages. therefore. were particularly conv spicuous in theconstruction of radially traversed l rotary machines.

According to my invention, I proceed from the conception that these disadvantages which occur particularly in the construction oi.' radially traversed rotary machines are based on the fundamentally incorrect attempt to provide as many blades as possible on as few discs as possible, and I propose in contradistinction thereto to employ. the saving in axial-length resulting from the radial arrangement of the blades for arrangingas many radially traversed blades as possible on the smallest `possible mean diameter. According to the invention, I attain this-object by distributing' known to be necessary for avoiding overstressing by centrifugal force of the outermost rotating' bladesor the devices supporting them-or for producing oppositely directed axial thrusts. In such an arrangement I dispose only comparatively few blades on a bladed disc. The diameters of therdiscs are thus kept comparatively small, vso that the-surface offered to thepressure of the working medium and, therefore, the absolute thrusts exerted on the discsremain small. In

The mean diameters of a selected quantity of radially traversed reaction v'blades among aA larger number of discs than is 2 this way it is surprisingly easy'to diminish the absolute axial thrusts, or to maintain the differential between oppositely directed thrusts within safe limits and thereby avoid any danger to the thrust bearing.

By the reduction in blading diameter the further advantage is obtained that small speeds ,of `flow of the working'medium can be advantageously employed and that the hydraulic losses are greatly diminished. It is known that small speeds of flow themselves result in smaller ilow llosses;l in addition however the blade channels turn out larger themselves in consequence of the diminution of the blading diameter (diminished periphery) and alsoin consequence of the slowing down of the flow whereby the edge losses and clearance losses diminish comparatively greatly.

On the accompanying drawings, are shown diagrammatically and by way of example various constructions according to the present invention in its application to steam turbines. All of the figures of the drawings show vertical sections along the middle axis of the turbine shaft. In said drawings,

Figure l shows a multi-stage condensing turbinek working with high head but with normal quantities of steam, theblading being distributed von the two shaft ends of another rotary machine,

for example a generator, so as to equalize the thrust; l

Figure 2 shows an arrangement similar torFlgure l but for larger steam quantities, and involving a duplicated arrangement and parallel traversal of 'an aidally traversed blading and the immediately preceding radially traversed blading inl the lowest pressure stages;

Figure 3 shows the arrangement of all the blades of a'condensing machine on one end only of the shaft of another rotary machine, the labyrinth disc provided for equalization of thrust being arranged close to the rotating wheel which carries the axially traversed blading and in view of its weight is disposed near the bearing;

Figure 4 shows a 'solution which lies betweenthe solutions shown in Figures l and 3 in. that the one shaft end of the driven rotary machine carries all the blading and the other shaft end the equalizing discs;

` Figure 5 shows a condensing turbine in whichv the 'steam pressure is rst reduced in a Curtis blading to s uch yan extent that with the reaction blades disposed according to the invention the total thrust does not overload the thrust bearing;

and

Figure 6, finally, shows a turbine with a separate shaft carrying all the discs between the bearings of said shaft and provided with a colt-- pling to drive another rotary machine.

In Fig. 1, the parts marked I represent the bearings which carry the shaft 2 and are arranged in the housings 3. The packing between the turbine and bearing housings is effected by the labyrinth packings l. Certain leakage quantitiesescape for example through the pipe l. 'Iheshaft ends 2 are extensions of a shaftwhich carries a rotorofl a driven rotary machine, for example a, generator (not shown) The free `shaft ends of the shafts 2 carry a plurality of radially traversed bladings ci, an, aa, 'a4 etc. The

rotary part of this blading is carried by the discs b1, bz, bs, b4 etc.. and the stationary part by the disc ci, ci, egel etc. As may be seen from Fig. 1, the bladesof the above mentioned radially traversed blading are distributed on a large number of discs and the number o! rows' of blades of `stages because the greatest head is here trans? diameters of the last traversed blades of the disc 5 ba as such blades-possess-the maximum blade lengths and therebyv the greatest centrifugal force stress. Smaller diameters are, however, preferably chosen for the other'discs, especially for discs a1 to a5, which are traversedby steam 1 of high pressure and which create .the greatest axial thrust,- in order to keep the axial thrusts small. I'he blades are therefore distributed 'on a larger number of discs than would be necessary by the general use of such large outsidedi- '1 ameters as arepossessed by the last traversed blades ofthe disc bs, the-number and size of the rotating discs being such that the blades of at least one ofthe discs can be distributed in the distributed on a number of discs.

It is important for the effective'reduction of the axial thrust and for simultaneous maintenance of good conditions of iow that a substantial proportion of the reaction blades should be traversed from the inside or that blades distributed among a number of `discs should be provided which are traversed in a radially outward direction. It is known to be advantageous to transform a larger head in the rows of blades y withincreasing peripheral speed o i the blades. The outermost rows of blades of the radially traversed blading therefore transform a larger head than the inner rows. 0n the other hand, a I

larger drop of pressure accompanies a given head a,

of Woking medium with higherpressure of the working medium. Ii' therefore the blading is traversed radially from outside to inside the largest drop in pressure is produced in the outermost# lform oi' additional rows on at least certain of 20 formed and because at the same time the works ing medium on entering from outside l outermost rowsof the blades possesses the highest pressure. In the 4inner rows of blades the` head transformed diminishes and also the pressure of theworking medium whereby the drop in pressure effected by both influences .is dim-inished; 'I'he described inuences have a reverse eifect on each other and, therefore` act in the sense of the equalization of pressure differences in a blading traversed from inside to outside. However, the surface oiferedto the pressure difference of the working medium is larger in the outer rows ofblades, corresponding tothe greater periphery, than in the inner rows of blades, so that an increased drop in pressure towards the outside results in an increase in the total thrusts vwith the same total pressure drop. A blading into th* progressive expansion of the working. medium.

- direction.

The discs b1 to ba and ci to en, on which radially traversed blades according to the invention are disposed, the pressure being different in at least each second row of blades, are arranged axially one behind the other, i. e., they are .traversed consecutively by' the working medium. In consideration of the great advantages ofthe outwardly directed traversal, and also with regard to diminishing theheat exchange through the discs, only one slide of the surface of discs disposed between other discs carries radially traversed blades, the interspaces between the unbladed disc sides of adjacent discs servingfor returning the working medium. 'I'hus by the exclusive or nearly exclusive use oi' blading traversed radially towards the'outside only one side of the Idiscs bi, bz, bs, b4, etc., and of the discs ci, cz, ca, c4, etc. is bladed, whilst the steam returns on the rear side of the discs from the outer periphery towards the center.

As 'according to my invention oftenv as many discs as possible are to be provided on one shaft, it .is vof extreme importance that stationary and, rotating discs which carry radially traversed blades should be of axially, undivided construction whereby erection andrremoval take place inaxial were axially split -inv order to permit of inspecting the blades by simply lifting off the upper halves of the stationary blade carriers as is customary in the construction of axially traversed i' turbines, there wouldbe a quite' substantial limitation inthe possibility of accommodating the dlcs. The axial'split line ofthe discs involves a very considerable weakening of the discs as tangential stresses which in the main are producers of stiffness of the discs can no longer form undisturbed but are in the main relieved by the axial joint. Discs provided with an axial split line, therefore, have to be constructed of greater thickness, which construction, in the case of a plurality of discs, results in a substantial increase in theleng'th'of construction. Moreoven the provision of an axial joint in the stationary discs is only advantageous. when, as describedabove, a`

provisionk of axial joints in the attachment of Vradially traversed blades has further constructi'onal disadvantages which are particularly marked when the free blade ends are supported by carrier rings as has been .shown` to be necessary in practical successful constructions.- Therefore also the stationary discs' c1 to ca are all of integral construction so that tangential forces arising from the axial thrusts caused Abv* the steam pressure, resist distortion of the discs.

I have obtained a particularly compact con 'struction ofthe discsbi to bs and c1 to cs by ar-I ranging the parts in such manner that the radially traversed blades a1, a2, as, a4 etc. -are supported by tangential annular elements or rings.

a' of closed construction which are connected on one side with the blades byconnecting webs to form thin thermally flexible discs, the axial thickness of the webs not exceeding or not appreciably If, for example, the stationary discs exceeding the .radial thickness of the carrier ring, asv described and claimed in my copending application Serial No. 600,500. By thermally ilexible is hereby to be understood that no special linkages between the carrier rings and the discs, -which would increase the axial length, are necessary in order to allow the aforesaid carrier rings a capacity of expansion or contraction on change of temperature of the working medium which is practically as great as that possessed by the carrier rings which are connected only to the blades. Such thermal flexibility of the vcarrier rings is necessary to obtain minimum' packing play within the blading. By diminution of the axial thickness of the discs, therefore, a diminution of axial length is effected in adouble sense and multiplies itselfcorrespondingly by the provision ofv a plurality oi discs and thereby renders possible the accommodation of this plurality of discs.

so thin that with minimum axial length they can at once follow all variations in the thermal condition of the steam, so that the interposition of special flexible connections between the carrier rings and the discs is superfluous.

It appears at iirst as if the blading diameter of the axially juxtaposed discs could not be sufllciently accommodated to the increase in volume of the working medium. I have found,` however,

that surprisingly good results are obtained by a'- blades. In this way it is possible to fix each discV for itself, e. g. by caulking, as the larger discs can be slid into position undisturbed over the supporting shoulders for the smaller discs.

The mean diameters of the bladings a1, az, aa,

a4, etc. are therefore made to increase from disc to disc in the direction of fiow and accommodate themselves satisfactorily thereby, with simultaneous increase in the steam speed, to the increase in steam volume. Likewise, the internal diameters of the discs increase from'disc to disc and thereby it is rendered possible to provide on the bushes 1, carrying the rotating discs, shoulders 6 which are necessary for taking up the axial thrust of the rotating discs b1, bn. bs, tu.,

etc. but which do not prevent movement of the discs axially into place along the bushes,

The subdivision of the radially traversed bladesy among a larger number of discs does not "exclude the increase of the vdiameter onwhlch the Hence the discs are rigid against thrust but can be made outermost blades of the last discs in the direction of flow of the drivingmedium are disposed to a.

limit which appears permissible in view of the stresses due to centrigufal force when, for exaxially traversed blading. In view of vthe substantial weight of rotating wheels which must support such axial blading, I prefer to arrange the rotating wheel carrying the axially traversed blading between a bearing and the radially traversed discs in order to relieve theshaft.

In-Fig. 1 the external diameter of the last radially' traversed disc bs is extended up to the limit which appears permissible in .view of cenview of the large steam volumes.

trifugal stress. The large surface of these discs has practically no iniluence on the magnitude of the axial thrust, as the steam pressure here is already very-low. 0n the other hand, a large blading diameter is much desired in this place in The volume in the last low pressure stages of the turbine is already s'o large that an axially traversedlow pressure blading 8 is provided. The rotating blades of this low pressure blading are arranged on a rotating wheel 9 and the stationary blades on an axially divided ring Il). The heavy rotating wheel il isidisposed, in view of the load on the shaft end due to its very great weight, between the bearing l and the radially traversed discs be, b1 and bs. I

Fig. l shows an overhung arrangement of the radially traversed discs h1, bz, ba, b4, etc. on the shaft ends 2 of the rotary machine (not shown) e. g. a. generator. Quite special advantages result fromV such overhung arrangement of the radially impinged discs on the shalt ends of ro tary machines, for instance, packing oi the shaft against thefull pressure of the working medium maythen be completely avoided. I'he most valuable machine results, however, when radially impinged discs are disposed-in an overhung manner on both'sha'it ends of another rotary machine as shown in Fig. 1. The opposed'construction as described above for axially traversed rotary machines can then .be employed and all packing against full working pressure can be dispensed with, but notwithstanding, a ,disproportionately large number of radially traversedblades are accommodated on a number of axially juxtaposed discs whereby the absolute axial thrust is kept within permissible limits.

The overhung arrangement of the discs involves the further advantage that a simpler, cheaper and more compact total construction is obtained. The enclosed machine unit can be supportedr in the simplest vway---for example in case of steam tur.bines-on.the condenser and can ltherefore often be shipped in the built-up condition whereby substantial foundation and working costs are saved. In particular there is no coupling up of separately journalled power transmitting shafts and the single shaft which is supported in two bearings only can be balanced so as to be practically free from oscillation, such condition not being disturbed by any coupling with powertransferring shafts.

The same idea of diminishing axial thrust can be applied to the packings between working medium and bearing oil. To this end I arrange that corresponding to the axial juxtaposition of the radially traversed blade carrying discs the packing devices, which in known manner possess radially arranged throttle positions,A should consist of several axially juxtaposed discs.

The labyrinth clearances in the steam packing l are accordingly dividedamong several rotating discs di and d2 as well as stationary discs ci, en.. in order to keep small the axial thrust of these discs.

In Fig. 1 the rotating discs b1 to ba are distributed upon the two shaft ends 2 of a rotary machine'for reasons above described. The steam enters in the high pressure housing I I at l2, iiows consecutively from the interior outwardly through the blades a1- a5, and leaves the housing again at I3. The pipe line I3 leads the steam into -pressure discs.

vcreased in this manner.

bearing.

the bearings and radially impinged discs.

amasar the low pressure housing il, and the steam ows consecutively through the bladings as, a1, as, and

8 and finally escapes through the exhaust steam pipe L. As the steam pressure decreases within.

the bladings a1, m, as, ai, etc., a lower pressure is exerted on the rear sides of the rotating discs b1 to br than on the bladed sides oi' the discs and 1 discs, arises which is equalized through the housing of the rotary machine (not shown). Any differences in thrust which arisev are small as the absolute values of the axial thrusts are small in consequence of the small diameter of the high taken up by the' thrust bearing (not shown) -of the rotary machine, such as a thrust bearing of the type shown at 21 in Figs. 4 6.

The above described devices concern principally discs with radially traversed blading, which are juxtaposed axially and traversed consecutively by the working medium. The stated constructions meet diiliculties, however, when driving media of'very large volume are Ito be operated with, in particular in the construction of the low Ypressure bladlng. Itis known to reduce the blade lengths necessary'for operating with driving media of. large volume by arranging that the blade groups are multiple and are traversed in parallehaxially traversed blade groups being conveniently disposedv after radially traversed blade groups, as these can be constructed with larger admission diameters.

Parallel traversed blade groups in the case of radially traversed blades which, as is known, are advantageously supported at both ends by closed carrier rings, can be amplified up to certain limits by the provision of blade rings additional to the yhead rings of blade rings already supported on one sideyof the blade carriers.. T'his'juxtaposition of blade rings soon reaches a limit, however, in viewof thedanger of oscillations and of overstresslng by the sum of the torques. Besides, the blade length of axially traversed blade groups which. as shown in Fig. 1. sometimes followthe radially traversed blade groups cannot be in'- One is therefore compelled to arrange separate blade carriers parallel to one another and to provide between them the necessary space for the inflow and outilow of the 4 They can without danger be shaft end as those blade groups which must operate with driving-medium of large volume, and consequently'possess large diameter, considerable blade lengths and large weight, must be arranged in the immediate neighborhood of the bearing in view of bending and critical speed` of revolution of the shaft end.- 'I'he parallel larrangement of such blade carriers onone and the same shaft end would-result in non-permissible wide spacing ofV at least one of the blade groups from the In a further development of the invention I therefore propose that rotating wheels carrying axially traversed blading be arranged on both shattends of another rotary machine between Ihe axially traversed bladings are then traversed in medium possesses high pressure and small vol-,

parallel in known manner, Hereby one half of two parallel blade groups traversed in radial directio'n can be disposed in iront of each of the parallel blade groups which are traversed in axial stages are disposed at the' rear of similarly divided.

and parallel traversed radial stages.

It is not advantageous in the case of rotary machines which are to be operated 4with a normal total head of the driving medium, to construct both sides completely symmetrical, i. e., to divide all the blade groups. 4and to traverse them all in parallel. Not only would in this case the blade length be small and the clearance losses great in those blade groups in which the driving urne, but it would above all be difilcultto accommodate on each side the total number of stages necessary for satisfactory utilizationv of the full head. It is therefore important .to employ the double flow, i. e. the parallel arrangement of ythe blade groups in the region ofgreat volume of 4the working medium, i. e. preferably in the region of low pressure, and in the remaining part of the blading on the other hand to employ the singie flow with provision of as many consecutive stages as possible. In vicw of the great importance of this task, .I construct the apparatus in such a way that the blade groups which are first traversed by the working medium entering the machine are arranged near the one half of the parallel traversed blade groups on the same shaft end, and that the blade groups traversed next by the working medium flowing out of the above bladc groups are located near the other half of. the parallel traversed blade groups on the other shaft end. In this way, I obtain the best possible distribution oi'. theblade groups in relation to bendingV and critical speed'of the. shaft end, as

now the heavyblade .groups which operate with" driving medium of large volume can be disposed in the immediate neighborhood of the bearings, whilst the preceding light stages are located at theends of the' shaft where they may be provided in greater number inconsequenceof their light weight.

In order to be'able to dispose the so arranged blade groups in series in llarge number at the beginning of the transformation of energy of' the working medium and in parallelat'the-,end

of the transformation of energyI propose, as a'.

further development of my invention, to carry out the operation in such a waythat the total working` medium as far as it transforms-its full energy in the rotary machineis led after partial the driven rotary machine to the other shaft end,

transformation of energy from one shaft'end of and that a part of the working medium after further, but not yet complete transformation of energy fiows back again to the iirst mentioned shaft end, whereby the remaining transforma' .tion of energy of the Working medium takes place at both shaft ends. .A tapping off, if such is requiredfisl neglected in the above description. One` emodiment of this form of my invention is shown in Fig. 2 which is diierentlated from Fig. ^1

pressure housing Il. Here the whole mass ofl steam iiows through only .the bladings ai and as whereupon only one 'half f the steam traverses the bladings as and 8 whilst the other half lis y led back to the highA pressure housing Il through the pipe IG. This steam then traverses the bladings a1 and 8a, i. e. the bladings as and a1 as well as the bladings 8 and 8a are traversed in `parallel by steam of the same pressure as otherwise the blade lengths would become very large in consequence of the large volume of steam. Between the steam leaving the bladingaa and the steam entering the bladiug a7 a packing l1 must naturally be pro- 'vided which is vconstructed of packing clearances distributed on discs. The steam iinally iiows away through the two exhaust connections I5 and lI5a. V

The arrangement shown in Fig. 2 hasthe particu- `lar advantage that thebla'dings a1, a2, as, a4, and as traversed by steam at high pressure possess a low traversal diameter in consequence of the axial juxtaposition of the radially traversed discs b1, b2, ha, b4 and b5, and thereforesmall axialy thrusts and large bladel lengths are realized, whilst in the region of 'low pressure, on the otherhand;`

bladings as, av, 8 and 8a traversed in parallel by large steam volumes can come into use, This ensures favorable distribution of weight and equalization of thrust. 'In other respects, all that has been said in connection with Fig. -1 applies just as well to Fig. 2. 'It applies also to the following Figs. 3 to 5 with the exception that in these figures all blades are arranged lon one and the same overhung' shaft end and that the axial thrust is equalized i-n different ways byspecial arrangements.

. .The advantages of diminution. of the absolute axial thrust by thedisposition of the radially irnpinged .discs` in series according to the inventionl arise also when the axial thrust is equalizedby special labyrinth pistons or labyrinth discs. If, however, the advantages are to be 'fully realized,

great care must be taken that good packing con`` I ditions exist for the labyrinth pistons or discs. It is important to keep small the overhang of the free shaft vend of the rotary machine as this exer-i cises great influence on they possibility of maintaining the extremelyiine packing play. Even in a two bearing system, such as is obtained by an in proportion tothe distance from the bearing centre and produce, therefore, with increasing overhang an increasing wearon the packing points and, thereby, an increasing enlargement of the packing play whose maintenance at low values on the other hand is of extreme importance for the attainment of high eilicien'y. In recognition of this fact, ithas already been proposed to dis? pose the parts which are most sensitive in regard to the maintenance' of packing play as close as possible to a bearing. In machines with a vpressure equalizing disc this applies first -to such 5 disc, furthermore to the high pressure stages in which the volume oi' the working medium is still small. With decreasing pressure, i. e. increasing volumeythe harmful effect of a possible increasing clearance diminishes more and more. In machines in which axial thrust is taken up by a pressure equalizing d isc provided with labyrinths, therefore, an arrangement of 'the pressure equalizin`g disc in the immediate neighborhood ofthe journal has proved of value, the driving medium flowing to thevblading in the direction from the medium possesses already vthe greatest volume is then located further distant from the bearing.

In rotary machines with very. large iinal` volumes in which the last stages must be carried out withaxial traversal, such an arrangement has hitherto Yappearedimpossible. Ihe wheel carrying the axially traversed low pressure stages is'so harmful bending of the shaft end is to be avoided. As an example of such a case, steam turbines for condensation operation may be mentioned.

In a further development of my invention I provide a new arrangement which permits of disposing the pressure equalzing disc and low pressure wheel in close proximity to the bearing. Ihis arrangement consists in disposing a pressure equali'zing disc with axial thrust in the 'direction towards the bearing next to the rotating wheel which is arranged between the bearing and the radially'i'mpinged discs and carries the axially traversed blading so that the equalizing disc is located-between axially and radially impinged ldiscs or rotating wheels. This arrangement involves the further advantage that the rotating equalizing disc, which.' is constructed with very thin walls owing to the required thermal flexibility, lies against the rotatingwheel carrying the axially traversed low pressure blading, so that the axial thrust is transferred from the equalizing disc to the rotating wheel. A special support for the flexible equalizing disc can be dispensed with as the very strong rotating wheel can take up the axial thrust without being overstressed. A

lIn Fig. 3, therefore, in contradist'inction to Figs. 1 and 2, all the blading parts and devices forequalization of thrust are disposed on one overhung shaft and only of arotary machine (not shown). Here again the radially traversed bladings ai, az, as, and a4 are arranged in axial juxtaposition and behind them is disposed an axially traversed blading 8.. One of the novel features of the construction of Fig. 3 is the thrust equalizing discs I8`a and lab with the labyrinth |81 In order to give these a minimum overhang-distance from the bearing I-they are disposed immediately next to the heavy ,rotating wheel SI carrying the blading B which for its part is arranged i'acing the bearing in consequence of its large weight.

A so-calledregulating stage (action stage) for improving the part-load eiIlciency may be disulatin'g stage as a radially traversed stage and `posed in front of the' high pressure reaction` blading, but the space available for this purpose with normal constructions is not sumcient. The

v space required for axially directedv inflow. and

outiiow of the working medium is too large. In order torender possible the arrangement according to the invention I provide, therefore, the regobtain the space for the provision of the equalizing discs Ita and lbbetween the high and low vpressure wheels. In this way there 'results out' side the actionwheel also suilicient space for a corresponding arrangement oi' the nozzlel groups 2Il without the axial length needing to be increased to a non-permissible extent. The quantity -of working medium flowing out iiows inwardly directly to the first radially traversed high pressure stages al which are traversed from outwards inwardly and are advantageously arranged within the action stage 22.

As the working medium leaving the high pressure blading a4. vat the free end 'of the shaft in consequence of its great volume is led to the low pressure blading 8 through conduits 23 which surround theI Whole machine as a closed ring, special measures are necessary to lead the live `steam to the equalizing ldisc and highfrpressure time to the high pressureportion through pipes heavy that it 'is disposed/near to the bearing if I9 which are disposed elastically in a space inside the housing Il through which flows the working medium iiowing to the axially traversed llow pressure ublading. Suchpipes can easily be fitted in a pressure tight manner in the walls. As these pipes, however, are traversed by a hotter medium than the space through which they pass, particular care must be taken that the considerable lare to be led. -This arrangement ensures with certainty avoidance of distortions and bending ofV the housing or the walls in consequence of unequal thermal expansion such as would have occurred if the working medium had been led to the high pressure portion through cast-in channels.

In Fig. 3, the steam enters the cbnduits I! through pipes I2 and ilows then into the nozzle chambers 20. regulations several separate nozzle chambers 2II For effecting the known nozzle are provided; From them the steam flows through nozzles 2I to an action stage 22 which is traversed radially inwards and is supported by the disc b1, and thus space yis gained for the provision of the thrust equalizing discs lia and IIIb. 'I'he steam flows through the blading a1 from the exterior inwardly, then from the interior outwardly through the bladings az, as, a4, and is finally led through channels 23 p astthe pipes I9 "to the bladingj 8. 1- It leaves the machine through the exhaust port I5. Considering the axial direction, therefore, the flow of steam through the bladings a1, an, as, a4 is opposed to that through the blading 8. In this way it -is possible to compensate for the axial thrust on the radially traversed discs b1, bz, b3 and b4 which outweighs the axial thrust of the rotating wheel 9 by a thrust equalizing disc I8a 'disposed on the rotating wheel. The discs b1, b2, b3, b4 are arranged on a' common bush 1 in order to render easily accessible the equalizing discs I-Iia and Ib of the labyrinth I8. This arrangement is chosen as the diameters of these discs increase in correspond- Special cases sometimes arise in which on the one hand the accommodation of the pressure equalizing disc on the same shaft end'as the discs arranged axially behind each other between the latter and the bearing, has disadvantages or causes diiliculties, but on the other hand thev equalization of thrust by distribution of the bladed ence with the growth in volume of the working medium with the distance from the equalizing discs on both shaft ends ofV the rotary machine does not appear jjustii'led from economical considerations or meets technical diillculties in construction. For example, in case of large quantities of working medium the transfer npipes, which must c'onvey the total working medium from the one side to the other side after-.it is increased in volume to a large extent by expansion in the first housing, assume considerabledimensions.A These large pipes which in practice elongate differently from the rotary machine over which they bridge', l exercise considerable bending forces on the whole construction and may in certain circumstances Acause disturbing displacements.' Special expansion pieces must therefore be provided which must possess, together with sumcient power of resistance to the high pressure' of the working medium, also suillcient resilience. Sometimes space is lacking for the accommodation of the large transfer pipes. Finally, in many cases intermedi- -ately arranged auxiliary' machines hinder the transference of large torques of the rotary machine from or to both shafts ends. Also the packing of the shaft against the exit pressure of the high pressure housing may involve perceptible losses in working medium. -In addition, disadvantages or difficulties can arise from the accommodatlon of the pressure equalizing disc between the bladed discs and the bearing in such special 'driving medium as is necessary tov cqualize the.

axial thrust which is produced from the bladepor-,. tions disposed on lthe other end of, the. shaft..-l "f Furthermore, both ends of the shaft are to be cases. For example, the working medium must be introduced into the rotary machine from the periphery. If the working medium is very hot it heats up the housing one-sidedly and causes disvery many discs on oneshaft and owing to -increased losses in the blading. There isr also the important practical dimculty that the high temperature of the entering working medium are introduced near to the bearing.

InFlg. 4, therefore, discs b1 to bk and c1 to c4 carrying axially juxtaposed radiallytraversed blading a1 to a4 are arranged on one only ofthe two shaft ends 2 of another rotary machine (not shown) whilst on the other shaft end are disposed rotary bodies 2lb and 25h-.carrying packing 2l 4and 25 traversed by the driving medium which serve for the equalization of the axial thrust. The arrangement according to Fig. 4, therefore.

lrenders it possible to dispenser with the large transfer pipes and to feed to the rotary bodies disposed on the one end of the shaft only so much packed only against the low back pressure of the 'working medium. It is, therefore, possible to arrange the blading as well as the thrust equalizing device close to the bearings I, and the torque is transferred only through oneend Vof the shaft,

the other end being relieved from the torque and thus available for disposing auxiliary devices.

In Fig. 4 a larger number of blades than in Fig.

3 is distributedamong the same number of ro-` tatingdiscs4 b1, b2, bs, b4. According to thisj part of the invention, the bladings a1, az, an and a4 are hereb'y arranged in the most advantageous way, i. e. they are all traversed from the inner diameter outwardly.' Hereby an advantageous arrangement ofthe pressure equalizing discs 24a, 2lb. 25a, 25h with the labyrinth 24, -25 on the same -shaft endwith the bladed discs isf-'rendered impossible. On 'the other hand a divisione of the blading between the two shaft ends is not effected',y

whereby for lexample manufacture is` f made cheaper and the provision of largetransfer'pipes together with the transference of-'torques through both shaft ends is avoided. The rotaryjf-t'r'iist equalizng discs are provided on the-onheistaff* end where they are advantageously located near the bearing. Only a very small pipe 26 is provided for conveying tothe second .shaft end the steam necessary-for the equalization of thrust. Fig. 4 also shows the thrust bearing 21 necessary for takingup the difference in thrusts.

The arrangement of pressure equalzing discs and the leakage losses of working medium caused by themmay in many cases be avoided in turbines provided with an action blading as shown in Fig. 5. Here the steam enters by pipes I2 and expands `to a comparatively low pressure in the nozzles 2l. The steam then implnges the action blades 22 which comprise-two velocity stages (Curtis blading) supported by the disc 28, and flows through the radially traversed blades 'a1, a2. a3 and the axially traversed blades 8 leaving the machine through the exhaust port I5.

pressure on 'the discs b1. b2, ba an`d on the wheel 9 is small and easily taken up through the shaft -2 by means of the' thrust bearing 21. This con.-

struction is especially suitable for small machines with low admission pressure, as with the aid of axial. juxtaposition of several consecutively radially impinged discs according to the invention it is possible in many cases-especially whenV action stages are'iirst traversed-to diminish the. axial thrust to such an extent` -that it may be taken up by a-thrust bearing 21 so that all losses of working medium for the purpose of thrust equalization may be avoided.-4 In order to be able `to'accommodate asuflicient number of discs on the shaft. ends the axial thrust is equalized through the shaft 2 of the rotary machine which carries the discs in an overhungmanner. The

fthrust bearing 21'is accommodated on the other side of the rotary machine from that which carries the discs in an overhung manner so lthatl the whole space outside the bearing is available for accommodation of the discs carrying the. bladesand packing.

In Fig. 6 the inventive idea is applied to a con- :lensing turbine inwhich the discs b1, ba, b3, b4, bs and 9 supporting the blades a1, az, an, a4, a5 and 8 are arranged on a special Iturbine shaft 2 between two bearings I according to'the standard practiceA with axially traversed turbines. The steam enters the housing H at lllflows. consecutively .through the blades al-as and l leaving the housing-gat l5. The total axialthrust created by the action of the steam on the discs F11-brand the wheel 9 is taken up by the equalizing discs Ila with the labyrinths Il. These equalizing discs are supported by the common bush." in order to render accessible the discs bi-bs which are caulked directly to theshaft z The shaft 2 of the turbine may be coupled to a shaft 3| of any VThe total thrust created by the action of the `low kind of machinery to `be driven by lmeans of the coupling 30.

The constructions shown have, of course, been I given by way of example only, and the invention is not limited thereto.as various modifications may be resorted to within the scope of the apmeans o f a new method and apparatus for as semblingvand dismantling ythe machines and of correspondingly constructed packing devices as described and claimed in my copending application Serial No. 6\.-1,119. The packing devices I in Figs. 1-5 correspond tol the packing devices shown in said copending application. 4In the =same way the discs b1, bz, etc. and the discs c1. cz.

etc. and the manner of fastening them correspond to the constructions shown and claimed in my copending application Serial No. 600,500.

.By the expression reaction (steam or gas) turbine as used in this speciiication and in the appended claims, is to be understood a turbine in* which at leastvall of the rotating or all-of the stationary or all of the blade rows operate with reaction (the specially arranged `Curtis wheels bei-ng left` out of vconsideration in this connection). The expression the working` medium iiowing in the same general direction is intended to define the forward movement of the medium blades on each of said discs. carrier rings supporting said blades at both ends thereof, and stationary bladed discs cooperating with said rotary discs, the latter arranged to be impinged in series and on corresponding sides of the discs,

there'being apressure-drop through said blades and along said discs, the mean pressures acting upon the opposite sides of at least certain of said vdists beingn different and thus causing axial thrusts in thesame direction,the number of rotary blades lbeing such that theycan be distributed in additional rings on a smaller number of discs of larger diameter without causing overstressing by centrifugal force acting on the outermost rotating blades or on the disc or discs supporting them when the discs are driven at apprxirnately the rated speed of the machine, whereby the thrust on said discs is reduced, for a given total pressurev drop, as compared with the thrust on discs carrying the maximum permissible number of rows of blades, rotary bodies on said shaft, and.

packing devices disposed on said rotary bodies and traversed, by the working medium and adapted to create a pressure drop of the working medium along said rotary bodies which equalizes the in the axial direction, that is, the sequence in which the individual radial surfaces are swept by the medium one after the other. As will be apparent, the impingement of a disc in a radially .outward direction corresponds to an impingement upon the opposite side of the disc with the direction of impingement reversed, that is,` radially4 inward toward the shaft.

l. In a. rotary machine, such as, a 'steam or gas turbine, the combination of a shaft, bearings adapted to support said shaft, a driven rotatingv machine .part arranged on' said shaft between said bearingsprotary discs arranged o n a stubend of said shaft in overhung fashion, 'a number of radially traversed rows of reaction bladeson each of said discs, carrier rings4 supporting said f blades at both ends there-0f. and stationary bladeddiscs cooperating with said rotary discs, the latter impingedfin series. and on being arranged to be corresponding sides of the discs and there being a pressure drop through 'said blades andV along said discs, the mean pressures acting upon' the opposite sides of at least certain o f said discs being different and thus causing said discs in the saine direction,I

thrust of said discs, said discs being arranged on only one of the stub ends of said shaft while the other stub end carries said rotary bodies.

3. In a combination comprising a rotary machine and a 'reaction steam or gas turbine for driving said machine and designed for operation at a denite. rated speed, 'a shaft, spaced bearings supporting said shaft, a rotating element of said machine being arranged on'said shaftbetween said bearings, a plurality of discs disposed on a stub end of' said shaft in an overhung fashion, rows of reaction blades arranged 'on sov each of said discs for radial traversal by a working medium and exceeding the number suitable for use in one Curtis stage, the number of .said

blades being such that they can .be Idistributed on a`smaller number of discs of larger diameter without causing overstressing by centrifugal force acting` on the outermost rotating rows `of blades or on the disc or discs supporting them when the discs are driven at approximately ,said

ra speedystaticnary bladed discs cooperating wi h said first-mentioned discs, a rotating wheel, blades adapted to be axially traversed arranged on said wheel, said wheel being positioned between the bladed 'discs and a bearing, and a pressure equalizing disc for exerting an axial thrust in the 'direction ofthe bearings, said equalizing disc being arranged nextto said rotating wheel and beaxialthrusts upong the number ofrotary blades being such" that they can be dis'- tributed on a smaller number of discs of larger diameter without causing trifugal force blades or on. the disc or'disos supporting bycentween said bearings, rotary discs arranged on al stub end of said shaft in overhung fashion, more than three rows of radially traversed reaction -tween wheel and the bladed discs.

. 4`.Tne combination of t'wo rotary machines,

auch as avreaction steam or gas turbine and a machine thereby,v including a'shaft, bearings supporting said shaft intermediate its ends,

rotating parts of one of said machines arranged on said'shait between said bearings, rotary discs when the` discs' are driven at approximately the l med on'both stub ends of said shaft in over" hung fashion, radially traversed rows of reactionblades on each of said discs, carrier rings supportin'g'said blades at both ends thereof, stationary bladed dises cooperating with said rotary discs, there being a pressure drop along said discs mman ma blades, .conduits for leading the driving medium to said rotary'discs in `such manner that the mean preures acting upon the opposite sides oi' at least certain of said discs is different and'causes axial thrusts upon said discs in the same direction, the number-of rotary blades being auch that they can be distributed on. additionolringsonamailernumber ofdiscsoi 'r 10ans? Y larger-.diameter without causing overstressing by centrifugal force acting on the outermost rotating blades or on the disc or discs supporting them when the discs are driven 'at approximately the rated speed of the machine, whereby the total thrust on said discsis reduced. for a given total `-pressure drop, eompnred'witn the total thr'ust on fewer lbut larger discs carrying substantially' the same total number of blades.

4hung fashion, radially traversed rows of reaction blades on each of said discs,-carrier rings support-v ing `said blades 'at both ends thereof, stationary blades discs cooperating with said rotary discs, there being av pressure drop through said blades, conduits for leading the drlvingmedium to said rotary discs in such manner that the mean pressures acting upon the opposite sides of at least certain of said discs is different and ycauses axial thrusts' upon said discs in the same direction, the -number of rotary blades being such that they can be distributed in additional ringson a smaller number of discs of larger diameter'without causing overstressingV by centrifugal force acting on the outermost rotating blades or on the disc or discs supporting them when the discs are driven at approximately the rated speed of the machine,v whereby the total-thrust on said discs is reduced. for a given total pressure drop,I as compared with the total thrust on fewer butlarger discs carrying substantially the same total number o1' blades,`

.and rotating wheels on said shaft carrying axially traversed blades, wheelsbeing arranged behind the last radially traversed blades and being disposed on both stub ends of said shaft betweenV t' the radially traversed discs and the bearings:

- 6; In a rotary machine, such as a reaction steam or gas turbine, ,the combination of a shaft, rotating discs arranged on said shaft, a plurality of'radially traversed rows of blades 4ori each of said discs to be lmpinged by a working medium and exceeding the number suitable for use in one 'Curtis stage, stationary bladed discs cooperating with-.said matins discs, end nnnuis elements supporting the rotating blades at both ends thereof, the pressure beingdiilerent lnat least each 1 second row of said blades, the rotating discslbeing garranged to be lmplnged in series and on corre-l sponding sides of the discs, the working flowing at diii'erent average pressures along the, two sides of atleast certain of said discs and in the saine general direction, thus exerting` axial thrusts upon shaft in thesame direction, said l. bladesbeing distributed a'mong such a number of discs who diameters are considerably less than the maximum permitted bylthefcentrlfugai force actin'g.f at the rated speed of the machine that the' blades of nt least one dise een be disinbuted upon ,the einer discs withoutcausing their diameters te exceed said whereby the sum of the thrusts exerted upon the shaft is reduced for a' givenpressure op,ascon'ipared withthesum of the thrusts on a smaller number of larger discs.-V

-'l. Themethodofreducingthetotaiaxialthrusto ,n a plurality of discs having radiallyimpinged ofireactionbiades .at the corresponding indesl thereon-the rows exceeding the number suitable y for use in one Cu'tisstage, theaverage ,on the opposite sides of each disc being different tion.' which compris distributing the blades necessary to effect the rrequired pressure drop through the machine upon'such a number of `discs having outer diameters 'considerably below the maximum permitted bythe 'centrifugal forces acting at the rated speed of themachine that the blades of at least one of the discs can be dis- 'and the the-same directributed in an additional row or rows on the re`- maining without causing increase of the outer diameter of such discs beyond-said xriaximum dian'ieter.-

8. Apparatus according td claim 6, wherein the mean diameterof said discs increases 'from disc to disc in the 'general direction of the ow of the working medium. 1 s

9. Apparatus according to claimV 6; wherein the .inner diameter of the discs increases from disc to disc in the general direction oi' ow of the working medium by at'least the radial width of one blade row.

1U. Apparatus according to claim 6. wherein the outer-,diameters oi the discs increase from disc to disc in the general direction of now bfthe vworking medium.

il. The combination according to claim 8,

wherein the sum of the axial thrusts created by the action of the workingmedium-on saiddiscs is lequalized through said shaft' and taken up by oppositely acting mechanism at theiother end of said shaft.

I2. The combination 'according to claim 5, wherein said axially traversed blades are trav-f ersed in parallel. while .the blades iirst radially traversed by the `working medlum entering the machine are disposed near the one,half of said axially andin parallel traversed blades-on the blades on the other stub end of said,

end. and means for conveying part of the working mediuii after further but not yet complete transformation of energy at said other stub end back to saidi'lrst mentioned stubend, the transformation of the remaining .energy of theworking medium thus taking place st both' stub ends.

i4. In a rotary machine, such as a reaction steam or gas turbine, the combination of a shaft.

rotatingV discs arrangedon said shaft. a `plurality of radially traversed rows of blades on each of said discs to be impinged by a working medium in the radial direction and exceeding the number f suitable for Ause, in one Curtis' stage, stationary bladed discs cooperating with said rotating discs. annular elements supporting the rotating blades at both ends thereof, there being a pressure dro'p along said discs through said blades, and conduits .ier leading ine driving medium to said rotary.

in such manner that the mean' pressures acting upon'the opposite' sides orsi .least .certain o f said discs are diifer'entdand cause axial thrusts upon said discs'in' the same direction, the number of rotary bladesbeing such that they can bedis- /tribud on additions; rings on a `simmer number of discs of larger diameter without overlstressing by centrifugal force acting on' outer,-

is .I

proximately the rated speed of the machine,

v whereby the total thrust on said discs is reduced,

for a given total pressure drop, as compared with the total thrustpon fewer but larger discs carrying subnantially the same total number of blades.

Patent No. 2,102,657.

CERTIFICATE or CORRECTION.

ULRICH MEININGHAUS 15. A rotary machine as set forth in claim 14 wherein the diameters of the successive discs increase in the direction of fall of pressure of the working medium, the higher pressures thus acting on discs of smaller diameters.

umori nmININGHAUs. v

nagelneu:- 21, 1937.'

It is nerebyeer-mriee that er1-o1:-4 appeara ,in the' 'pzinsee specification' ef the above numbered patent requiring cerrectonls follews Psi-gre 9 second column; 1ne26, claim 11, for the claim reference 4rrurlierall "8"' read l; mid.v thet 'the said Letters uPatent: should be read with this'correctlbn therein that the same may conform to the record eff-121:16 case'1n`the Patent Officer..

Signed and sealedths ist' day of March, A. D. 1958. l

(Sea1} Henry Van -Arsdn'1e Acting Comssionerof Patents.

proximately the rated speed of the machine,

v whereby the total thrust on said discs is reduced,

for a given total pressure drop, as compared with the total thrustpon fewer but larger discs carrying subnantially the same total number of blades.

Patent No. 2,102,657.

CERTIFICATE or CORRECTION.

ULRICH MEININGHAUS 15. A rotary machine as set forth in claim 14 wherein the diameters of the successive discs increase in the direction of fall of pressure of the working medium, the higher pressures thus acting on discs of smaller diameters.

umori nmININGHAUs. v

nagelneu:- 21, 1937.'

It is nerebyeer-mriee that er1-o1:-4 appeara ,in the' 'pzinsee specification' ef the above numbered patent requiring cerrectonls follews Psi-gre 9 second column; 1ne26, claim 11, for the claim reference 4rrurlierall "8"' read l; mid.v thet 'the said Letters uPatent: should be read with this'correctlbn therein that the same may conform to the record eff-121:16 case'1n`the Patent Officer..

Signed and sealedths ist' day of March, A. D. 1958. l

(Sea1} Henry Van -Arsdn'1e Acting Comssionerof Patents.

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