US2226249A - Turbine - Google Patents

Description

Del; 24, 1940. LYSHQLM ErAL 2,226,249

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' Dec. 24, 1940. A. LYsHoLM Erm.

TURBINE Filed sept. 14, 1938 4 Sheets-Sheet 2 Bell 4 Sheets-Sheet 5 Dec. 24, 1940. AfLYsHLM grAL TURBINE Filed Sept. 14, 1958 l l x\\\\\\\\\\\\\ Dec. 24, 1940. A. LYSHOLM ETAL 2,226,249

TURBINE l Filed Sept. 14, 1938 I ..4 Sheets-Sheet 4 "fw y -m mmxwn Patented Dec.' l24, 1940 UNITED STATES PATIENT OFFICE TURBINE ration of Sweden Application september 14, 193s, serial No.' 229,808

' In Sweden September 15, 1937 The present invention relates to elastic fluid turbines and has particular' reference to turbines of the double rotation type. Still more particularly vthe invention relates to double rotation turbines of the kind in which the motive fluid is expanded in one or more axial i'low blade systems after having been previously expanded in one or more radial ilow blade systems in the same turbine. For convenience such turbines will hereinafter be referred to as radial-axial flow turbines.

' operation. In addition to the mechanicalstresses caused by centrifugal forces, there are also heavy stresses occasioned by the transmission of torque between the different parts ofthe turbine, particularly when the turbine is overloaded as for example when an electric generator driven by the turbine is short credited.

One of the 'principal objects of the present invention is to'improve tile construction, particularly the rotor construction, of turbines of the kind under vconsideration so that those parts which are subjected to high stresses due to temperature are relieved, las far as possible, from -high values of mechanical stresses, and vice Versa.

By segregating to a great extent the two classes of stresses into different turbine rotor parts, numerous advantages in turbine construction are obtainable which permit, among other things, of constructing' the blade systemss as to obtain highly efficient operation of turbines with rge capacity, Without subjecting the parts to t tal stresses of dangerously high values.

To this end the rotor construction is of builtup form comprising a plurality of disc-like rotor portions wherein the movingblades of the axial flow blade system of the rotor are secured to two or more axial flow turbine discs-which are carried by an intermediate disc portion' rigidly connected tothe turbine shaft and provided with passages extending substantially in. axial direction for the admission of motive iluid to the radial ow blade system. The intermediate disc portion can readily be designed to withstand the stressesimposed upon it in accordance with such design and the radial flow vdisc portions of the rotor are thereby accordance with prio yforms ofV apparatus in` which the axial flow turbine discs are carried by and transmit their torque through the radial ow turbi'ne discs.

It is a matter of fact-that the intermediate disc portion is -not subjected to extreme stresses due to centrifugal forces, which stresses one-the other hand are of higher value in the radial llow discs. It is therefore also highly advantageous to dispose the passages for the supply of motive fluid to the radial ow blade system in the intermediate disc portion rather than in tl'ie radial flow disc. Such an arrangement is also superior to previously proposed arrangements in which the passages for the supply of motive fluidv are arranged'in the turbine shaft which is subjected to peripheral stressesfrom, the entire blade 'systern ofthe rotor.

In accordance with the novelconstruction of thev present invention, the extent of the axial flow/ blade system can be enlarged as compared with systems heretofore employed, in a convenient manner and without risk, with the result that greater outlet areas and a greater value of the sum of the squares of the peripheral Velocities can be obtained. Because of this it is further possible to shorten the blades of the outermost blade ring of the radial flow system and thus avoid Athe necessity for using special construction for such blade ring.

Preferably, the laxial ow turbine discs are connected to the intermediatedis'c portion in such manner that each axial flow disc is carried by the intermediate disc portion by means of a separate sity of weakeningvthe radial ow. discs by bleegler passages'. y

A'further object of the invention is to increase the number of blade rings in the radial ilow blade system without the necessity of increasing the outer diameter of the radial flow system, thus rendering it'possible to admit motive iluid direct- 1y at very high pressures without using a special highpressure turbine to partially expand the zok motive fluid before it is admitted to `the radial .axial iiow turbine.

To this end the invention contemplates that at least the inner radial ilow blade'rings shall be carried by radial flow turbine disc portions each ofawhich is connected, either directly or indirectly, to the corresponding turbine shaft and that ythe disc portions of the rotor connecting the same with the. turbine shafts are provided with inlet passages for supply of motive uid which extend substantially lparallel to the turbine shafts and with the radial ilow discs projecting inwardly toward the axis of rotation of the turbine to a radius less than the distance between the axis of the inlet passages and the axis of rotation. In a preferred embodiment of the invention, at least the inner radial flow blade rings are carried by radial flow disc portions which are substantially T-shaped in cross-section, disposed in such manner that the ange portion of the T extends in generally radial direction and carries the blade rings, while the web portion extends generally axially and is located radially outside of the inlet passages to the radial flow blade system, which passages are substantially parallel to the turbine shafts.

Other and more detailed objects of the inven- 'tion and the advantages to be derived from its use in diiIerent specic forms of turbine construction will become apparent from the ensuing portion of this speciilcation in which there is described by way or example several embodiments of turbine structure for carrying the invention into eect.

In the accompanying drawings illustrative of such embodiments and forming' a part hereof Fig. 1 is a more or less diagrammatic central axial section of part of a turbine embodying the invention;

Fig. 1a is a view on enlarged scale of a detail of construction suitable for embodiment in a turbine of the kind shown in Fig. 1; and

Figs. 2 to 8, inclusive, are all views like Fig. 1 but showing different specific arrangements of rotor construction embodying the principles of the invention in different detailed manner.

Referring now to Fig. l, I indicates the shaft member proper of one of the two oppositely rotating shafts of a double rotation turbine, to which shaft member there is rigidly secured the hub portion I2, Rigidly ilxed to the hub I2 there is secured a disc portion I 4 constituting an intermediate disc and having axially extending passages I6 and I8 therethrough. At one of its sides the disc I4 is provided with radially spaced flanges and 22 and at its .opposite side two similar anges24 and 26. 'I'he construction further proyides two axial ow turbine discs 28 and .30. theriformer being provided at one side with a flange32 projecting between the anges 2li and 22and the latter disc 'being provided with a ilange 3 4 projecting between the flanges 24 and 26.

/Ihese flanges are provided with radial bores in which are located pins 36 and 38 which transmit the torque developed by the axial ilow discs to the intermediate disc and further serve to keep the several discs in their properly aligned axial positions while permitting a certainl degree of radial movement of expansion between the discs.

A radial iiow disc 40 is connected to disc I4 by means of bolts 42 and this latter disc is ,also

Y advantageously connected to permit of relative radial movement with respect to disc I4. Construction permitting such axial movement may advantageously be as shown in Fig. 1a in which flange oi' which projects between cooperating flanges on the disc 1. The cooperating flanges are bored to receive radially extending pins 46 which serve to hold the parts in proper axial position and which. also permit the desired relative expansive movement inl radial direction. In the construction described, the axial ow discs 28 and and the radial iiow disc 40 may be said to be carried by the intermediate disc I4 and as the term carried is employed in this specification, it win be understan/1 that between the parts said to be carried one by another, it is meant that there is a connection between the two which transmits torque but does not transmit from one to the other of the parts stresses due to centrifugal forces which are separately absorbed by the connected parts.

In.the construction described, the inner radial flow blade system is formed by a series of radial flow blade rings 48 carried by the disc 40, which rings interleave with a series of blade rings 50' carried by the rotor disc 52 which forms a part of the opposltely rotating rotor of the turbine. The latter is usually, but not necessarily, of generally similar construction, and for an understanding of the principles of the present invention it is suilicient to describe in detail/the construction of but one of the turbine rotors.

In the present embodiment an outer radial flow blade system is also provided, the blade rings. 54 of which are carried by the axial flow disc 28. The latter disc has fixed thereto rows of moving axial now blades 56 and '58 while the second axial flow disc 30 has xed thereto a third row of axial now blades 60. Cooperating with these blades are rows of xed axial ilow guide blades 62,'64, and 66, fixed to the stationary turbine structure indicated generally at 68.

The disc member I4 has secured thereto a labyrinth member 'I0 between which and a stationary labyrinth member 'I2 there is provided a radially extending labyrinth packing indicated generally at 14. Axially extending labyrinth packing I6 is also provided around the hub I2 of the turbine shaft.

Motive uid is supplied through the inlet conduit'fIB which terminates in a chamber 8l)A from which chamber the fluid ilows through the inlet the bolts 42 rigidly retain a ilanged ring 44, the Y passages I6 in disc I4 to a collecting chamber 82,/ As will be observed from the drawings, the radial flow disc portion 40, which is subjected to extremely high temperatures and also to high stresses due to centrifugal force, is not required to take up or transmit the torque developedby the axial flow turbine discs, the torque from these discs being transmitted to the intermediate disc portion I4, through which portion the tOrque .is transmitted directly to the turbine shaft. Also, it will be noted th'at the radial flow disc portion 40 is not weakened by passages, such as passages I6, for the supply of motive fluid to the radial now blade system. These passages are instead provided in the intermediate disc portion I4 which is not subjected to as high stresses because ofcentrifugal force as is the radial flow disc portion.

It will further be observed that the above described construction also makes it possible to project the radial ilow disc portion 40 toward the vaxis of the turbine to a comparatively short radius r which is materially less than the distance a between the axis of the inlet passage I6 and the axis of the turbine. As a result, a larger locities is obtainable.

number of radial iiow. blade rings is obtainable in the radial flow systemwithout increasing the outer diameterv thereof, -ascompared with pre-v vious forms of construction. As' a consequence higher initial motive fluid pressures may be employed than would otherwise be possible.

Since the torque from the axial ilow discs is transmitted by the intermediate disc portion I4 which has no blades, the number of axial flow discs andv moving axial ow blade rows can be increased an'd as a consequence a larger value of the sum of the squares ot the peripheral vevided for bleeding motive uid at an intermediate pressure. These expedients are known. By use of the present construction a further bleeder passage 88 is obtained betwe'en the radial ilow disc 40 and the axial ilow disc 28, which passage it will be observed is obtained without the necessity of weakening the radial flow disc by prolviding special transverse bleeder passages extending therethrough.

turbine construction is lbasically similar to that v It will further be observed that in accordance with the present construction the crosssection of the radial flow turbine disc portion is preferbly of. T-form, the. ilar'ige portion 40a of 'which is generally radial in extent and carries the ravdial flow blade rings 48 while the web 40b extends in generally axial direction and radially outside the inlet passages for the motive uid. In `the remaining embodiments, the general just described and for the sake of brevity and clarity, onlythe differences in construction as compared with the embodiment illustrated in Fig. 1 and pertaining` to the application of the prin'- ciples of the present invention will be pointed out. l

.In the embodiment shown in Fig. 2, the axial` ow blade system comprises three axial flow discs 90, 92, and 84, providing four rows of moving axial ow blades 98, 88, |00,"and |02. In

the present instance the end discs 90 and 94 are A secured directly to the intermediate disc portion I4 by means of bonds |04 a'nd |06 respectively of V the radial pin type, While the intermediate disc 92 is secured by means of the bond |08 to the disc 84. In other respects, the construction is essentially the same as that shown in Fig. 1.`

In the embodiment shown in Fig. 3, twoaxial Iow discs are employed which are attached to the intermediate disc portion I4 in a manner similar to that shown in Fig. 1, but in addition there A is provided a further bond ||0 of the radial pin type between the axial flow disc. 28 and the outer persiphery of the ilange part 40a of the' radial n flow disc portion 40.

In the embodiment illustrated in Fig. 4, as well as in the ensuing embodiments, the intermediate disc portion yand the radial ow disc portion are made integral, with the web part 40h of the T- shaped radial ow disc portion'extending axially to merge with the intermediate disc portion and be secured directly to the turbine shaft. It will be observed, however, that in this form of con- This in turnmakes possi- .sages I6.

the radial ilow disc portion carrying' the radial iiow blades is not weakened by these passages. In

the present arrangement the two axial ow discs ||2 and II4, the former having a single row ,of

blades ||6 and the latter having two rows'of blades |.I8l and |20, are carried at the periphery of the flange part 40h of the radial ow disc portion, disc I|2 being carried by a bond |22 of radial pin 'form and disc ||4 leing carried by a bond |24 consisting of radial 11s/Tus passing through interleaving flanges.. A thic ened portion of the iliaige part 40h provides for a bleeder passage The construction shown in Fig. 5 is generally similar to that illustrated in Fig. 4, but diii'ers therefrom by the fact that the first axial flow disc ||2, at the inlet of the axial blade system, is carried by the second axial flow disc |I4 through the intermediate of a ring bond I 28.

In the embodiment illustrated in Fig.' 6, the radially outer part of the radial flow disc 40 is 'of generally U form in cross section, yone leg or flange of the U being formed by the outer ange part 40a of the radial ilow disc por-tion and the other leg or flange |30 of which projects radially outwardly from the intermediate disc portionl with o served, the web of this U-shaped portion of. the\ section, as well 'as the web of the'T-shaped por-- tion o f the section, both lie outside the inlet pas- The flange part |130 carries the two axial ow blade` discs 28 andv 30 by means of a common radial pin type bond connection indicated at |34.

. In the embodiment `umarmen in afgaatm radial flow disc portion 40, which is integral with the intermediate disc portion I4, is T-shaped in cross-section and in this embodiment the'axial flow disc 28 is carried by a radial pin type bond |36 connecting the disc with the outer periphery of the flange part 40a of the radial ilow disc'por-l tion, while the axial ow disc 30 is carried y a 5.0 pin type .bond |38 secured to the web part ofb T section.

In the embodiment illustrated in Fig. 8, the axial flow blade system comprises three discs |40, |42, and |44, disc |40 being carried by -disc |42 through the medium of a bond .|48 and disc |42 in turn being carried by disc I 44 through the medium of a bond |48. The radial ilow and intermediate disc portions are -in this embodiment formed integrally and provide the characteristic T-shaped cross-section as wellas U-shaped crosssection previously described in connection with- Fig.- 6, the flange |30 of the U-shaped portion of the cross-section being connected by means of a bond |50 to the axial flow disc |44 which in turn carries th remaining axial flow discs.

In addition the intermediate axial flow disc |42 carries an outer or auxiliary radial ow disc |52 by'means of a bond |54. 'I-'he inner or main radial iiow disc portion carries the blade rings oi the inner portion of the radial ow blade system while the auxiliary disc 'carries intermediate radial ilow -blade rings I 58. Thefouterfradial flow. blade rings 54 are in this instance'alsocarri'ed by the intermediate axial iiow disc |42.

As will be evident from the foregoing, the

lrotor-designs and certain features of /construction within the scope of the invention may be used to the exclusion of others. It is accordingly to be understood that the scope of the invention-is not limited to the forms of construction hereinbefore described by way of example, but is to be considered as embracing all forms of structure falling within the scope of the appended claims when they are construed as broadly as is consistent with the state of the prior art.

What is claimed is:

1. In a double rotation radialaxial flow type turbine, a turbine shaft and a built-up rotor including one or more axial flow disc portions and a radial flow disc portion, said radial ilow disc portion being substantially T-shaped in cross-section and providing a generally radially extending flange part carrying radial flow blade rings and a Aweb part extending in generally axial direction, radially outside of passages extending in substantially. axial direction through the rotor structure for admission of motive fluid to the inlet of the turbine blade system.

2. A turbine rotor including the structure set forth in claim 1 in which said flange part extends radially outwardly to a radius greater than the innerradius of at least one of said axial flow discs.

3. A turbine rotor including the structure set forth in claim l, characterized by the provision of an intermediate disc portion secured to the shaft and carrying said web part and at least one of said axial flow discs.

4. A turbine rotor including the structure set forth in claim 1, characterized' by the provision of an intermediate disc portion secured to the shaft at a place axially offset from said iange portion and 'with vwhich said web part integrally merges,

the portion secured to the shaft having passages extending therethrough for admission of motive iluid to the inlet of the turbine blade system.

5. In a double rotation radial-axial flow type turbine, a turbine shaft and a built-up rotor including one or more axial ilow disc portions and a radial flow disc portionlsaid radial ow disc portion having a cross-srrzfion including a. generally U-shaped part ha y g legs extending outwardly in generally radiall direction, one of said legscarrying radial ilow blade rings, the other of said legs carrying at least one of said axial flow disc portions, and the web of said U-shaped part lying radially outside inlet passages passing through the rotor for admission of motive fluid to the inlet of th blade system of the turbine.A

6. A rotor'fo a double rotation radial-axial flow type turb e including three axial flow disc portions of which the ilrst portion, considered in the direction of now of motive fluid, is carried y by the second portion and the second portion is carried by the third portion. l v

'1. A turbine rotor including vthe structure set forth in claim 6, characterized by the provision of a plurality of serially arranged radial ow blade systems of which the inner system is carried by a disc portion transmitting torque to the,

. turbine shaft independently of said axial iiow disc portions andthe remaining radial owblade systems transmit their torque tothe second of said axial flow disc portions.-

8. In a double rotation radial-axial iiow type turbine, .a turbine shaft and a built-up rotor including one or more axial flow disc portions and a radial ilow` disc portion, said radial flow disc portion being substantially T-shaped in cross-section and providing a generally radially extending ilangepart carrying radial now blade rings and a web part extending in generally axial direction, radially outside of passages extending in -substantially axial direction through the roto-r structure for admission of motive iluid to the in-- let of the turbine blade system, said flange part extending radially inwardly vto a radius less than the distance from the axes of said passages to the axis of rotation of the turbine.

9. In a double rotation radial-axial flow type turbine, a turbine shaft and a built-up rotor including one or more axial ow disc portions and a radial ow disc portion, said radial ilow disc portion being substantially 'r-shaped in crosssection and providing'a generally radially extending flange part carrying radial flow blade rings and a web part extending in generally axial direction, radially outside of passages extending in substantially axial direction through the rotor structure for admission of motive iluid to-the inlet of the turbine blade system, said ange part also carrying one or more of said axial flow discs.

10. In a double rotation radial-axial flow type turbine, a turbine shaft and a built-up rotor including one or more axial flow disc portions and a radial flow disc portion, said radial flow disc portion having a cross-section including a generally U-shapedpart having legs extending outwardly in generally radial direction, one of said legs carrying radial flow bladerings, the other of said legs carrying at least one of said axial ow disc portions, the web of saidl U-shaped part lying radially outside inlet passages passing through the rotor for admission of motive fluid to the inlet of the blade system of the turbine,

and there being an intermediate disc portion inand an intermediate disc portion carrying said axial now disc portions and rigidly fixed to said shaft, said intermediate disc portion having passages extending. therethrough in substantially axial direction for,admission of motive fluid to the inlet of the blade system of the'turbine, and said intermediate disc portion carrying axial ilow disc portions on both of its sides.

12. In a double rotation radial-axial flow type turbine, a turbine shaft and a built-uprotor in' cluding a plurality of axial flow disc portions and an intermediate disc portion carrying said axial flow disc portions and rigidly iixed to said shaft, said intermediate disc portion having passages extending therethrough in substantially axial direction for admission of motive fluid to the inlet of the blade system ofthe turbine, the axial flow disc portion having the last row of moving blades in the path of flow of the motive iluid being carried directly by said intermediate disc portion and the remaining axialflow disc portions being carried by the last. mentioned axial ow disc por- Y tion.

13. In a double rotation radial-axial now type Y turbine, a turbine shaft and a built-up rotor including a plurality of axial flow disc portions 5 mediate stage of the turbine being provided between the axiallyouter surface of a radial flow disc portion andthe inner partof one or more l of said axial flow disc portions.

14. In a double rotation radial-axial ilow type turbine, a turbine shaft and a built up rotor including a plurality of axial flow disc portions and an intermediate disc portion carrying said axial iiow disc portions. and rigidly nxed to said shaft, said intermediate disc portion ,having passages extending therethrough in substantially axial di- -recti'on for admission of motive uid to the inlet an intermediate stage of the turbine being proof the blade'system of the turbine, a passage for bleeding motive iiuid from an intermediate stage of the turbine being provided between the axially ,'50 outer surface of a radial now disc portion and 'f the inner part of one or more of said axial flow disc portions, said 'passage extending through said intermediate disc portion.

l5. In a double rotation radial-axial flow type turbine, a turbine shaft and a built-up rotor including one or more axial iiow'disc portions and a radial ilow disc' portion, said radial ow disc portion having a cross-section including a generally U-shaped part having legs extending outwardly in generally radial direction, one of said legs carrying radial iiow blade rings, the other of said legs carrying at least one of said axial ilow `disc portions, the web of said -U-shaped part lying radially outside inlet passages passing through the rotor for admission of motive uid vto the inlet of the blade system ofthe turbine,`

and one or more passages for bleeding iluid from vided which passages extend through the axially outer leg of said U-shaped part.

4 ALF LYBHOLM.

GUSTAV KARL WILLIAM BOESTAD.

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