US2492833A

US2492833A - Rotor for multistage turbines and compressors

Info

Publication number: US2492833A
Application number: US710762A
Authority: US
Inventors: Baumann Karl
Original assignee: Metropolitan Vickers Electrical Co Ltd
Current assignee: Metropolitan Vickers Electrical Co Ltd
Priority date: 1945-11-20
Filing date: 1946-11-19
Publication date: 1949-12-27
Anticipated expiration: 1966-12-27
Also published as: FR1017742A; GB603996A; BE469282A; NL69944C; CH257531A

Description

Dec. 27, 1949 K. BAUMANN ROTOR FOR MULTISTAGE TURBINES AND COMPHESSCRS Filed Nov. 19, 1946 INVENTOR WI ATTORNEYS Patented Dec. 27, 1949 PATENT orelce uutrrsraor TURBINES si ner to Met e!) q atbriie l i litamvickers E ec r cal C di Leii n land, a com any o Application November 19, 1246, Serial No. 710,762

' In Great Britain November 1945 Clam 1 This in en ion l e to a ro or f r multista e turbines an r sso s, e dn ertleuler to bladed rotors therefor.

In the design of rotors having several rows of blades for use i h e -speed-mul i=stese-turbines or compressors, ther are, as he number and diameter of the bladi sta es inc ea serio s limitations to the use ofrotor constructions: of the drum type and also of the type inv ving separate discs mounted u on a shaf th se lime itations being accentuated in circumstances W ere m nimisa ion .ef eve a Wei t-is su eially mpo tant a fo exam e, is the ease wit t rotors of turbines o com ress rs int nd d for use on a rc af mor particu ar in the f a rot r o th rum t e, h ho p s r s is ab to bec me i ssiv w h eased i mr eter or i -dine pee Wh in t eaeee e rotor of the multi-disc type, the diameter of the shait must be increased correspondingly with increase n he numb r d ll en h o s ages in o e he? the r ti al s eed ha b meieie ed Wit a onab lim nd t su h iher e ha ame r h 1 S e a t b liable to become excessive and to cause shrinkage fit between the discs and shaft a con e uenc u t s h iieeee 9f t biae In e er to e o e imita i s ei to, resource has been made to theuse of a r constr ti n in lv g a l r it o dispslt. abutting together at projections termed solid with the discs at-a diameter considerably greater than that of the usual bores. With such c 11,-. struction a rigid structure having relatively h gh e r ii el speed is ter in which the d ee'ere held together at spigoted locations of contact by m ans of a ol passin thr eh el t vely small holes in the hubs, or alternatively by welded unions between the projections on thefdiscsi; this latter method is, however, unsatisfactory inasg much as, with the welding applied t [at of the disc proper, local stresses are uire ueed into disc, and si j e ghl stre se membe s ch leea gm] projection, 'or' several circularly-distributed projections, facing and in axial alignment .5 5

a similar projection or projections on the adja: cent disc, and the projection or projections on one disc being secured by pinning or riveting or bolting to an annular member which is rigidly attached, by welding, to an annular member'selcured by pinning or riveting or bolting t9 thepro; jection or projections on the adjacent disc,

Inasmuch as such welding as is utilised in effooting attachment between the discs is notaps plied directly to a disc proper, but on the. contrary to a member which is secured to the disc by being pinned, riveted or bolted to the disc projeo; ti'ont's), the possibility of introduction of local stresses into the disc proper is minimised.

"Adva'ntageously provision should be madeyfor clearance between the projection, or projections, on a disc and the annular member which isse; curedthereto by pinning or riveting or bolting, so that during application of Welding to said annular member (for attaching it to the annular member which is secured by pinning or riveting or bolting to the projection or projections of the adjacent disc) said annular member. can expand freely and with but minimum application of stress to the disc due to engagement .of said an: nular member with said projection .or prolens tions ofthe disc.

In carrying out the invention it isspreferable for the annular member secured to the projection or projections on one disc to be spigoted withrespect to the annular member secured to the projection or projections on the adjacent disc; advantageously the'annular member for one disc may be machined on a radial face remote from the disc so as to register with a'spigo't on to a corresponding face of the annular member for the adjacent disc.

'Go'nveniently the annular members for adjacent discs may be formed at the radially outer ed ges'of their contiguous radial end faces in such manner as jointly to form a recess for receiving wld'meta'l rigidly to attach the rings one to the other.

practising the invention, the projection or projections on the discs may be of any suitable form but it is'preferred to use a single continuous projection of cylindrical shape. The radial positionof the projection or projections will preferably be chosen so that during rotation at normal working speed there will be little or no sheer stress at the radial plane between the projection or projections of a disc and the face of'th disc F ggpgflflm I 'Wlth the projection or projections on a disc formed oylindrically and adapted to into annular space formed between a radially inner flange and a radially outer flange on the annular member to which said projection or projections will be secured by pinning or riveting or bolting as aforesaid, the said annular member will be constructed with said flanges spaced apart in the radial direction by a distance at least equal to the depth of the projection in the radial direction together with an amount corresponding to the distances by which the radially outer face' of the inner flange and the radially inner face of the outer flange can be expected to move in the radial direction whilst the welding operation is bein effected upon said annular member; also, the depth in the axial direction of the annular space formed between said radially inner and outer flanges will be such that, with the projection fitted properly in position between said flanges for pinning or riveting or bolting thereto, the opposing radial surfaces of the annular member and the projection within said space, are separated by an amount at least equal to the distance in the axial direction by which said radial surface of the annular member can be expected to move during the welding operation.

In a preferred construction, the annular members are secured each to the appertaining disc by means of radial pins inserted at the radially inner end of a series of radial holes formed in the annular members and the projection or projections of the disc, the contiguous annular members being secured together by welding effected whilst the discs are temporarily held tightly together and in coaxial relationship with each other.

For some applications the discs may be formed without central bores, the two end discs in the assembly being attached, in similar manner to that described, to members forming stub shafts for the bearings. By the omission of central bores in the discs the overall length of the rotor to accommodate a given number of stages may be reduced since the disc hubs will be more lightly stressed and may therefore be made narrower than is possible in the case where the discs are formed with central bores.

To enable the invention to be fully understood reference is made to the accompanying drawing, the sole figure of which is a half axial sectional view of a portion of a turbine or compressor bladed rotor constructed in accordance with the invention.

The rotor shown comprises a rigid assembly of discs I, 2, 3 which are formed separately and secured together in side-by-side and coaxial relationship in a manner presently to be described. It will be appreciated that the discs will be shaped at the outer periphery as indicated for disc I at la so as to form a base for attachment thereto of one or more rows of blades (not shown).

For the attachment of the disc I to discs 2, 3, said disc I is formed on opposite end faces with integral cylindrical projections lb and la respectively; said projections are preferably located at such radial distance from the axis of the disc that under the normal speed of rotation about said axis there will be little or no sheer stress in the neighbourhood of the plane indicated at XX. Discs 2 and 3 are formed with similar projections 20, 3b respectively facing, and at the same radial distance from the axis as, the projections lb, lc for disc I.

.4 through the intermediary of two ring members 4 and 5 respectively. Rin 4 is formed with flanges 4a and 4b to provide a recess into which the disc projection lb fits with radial clearance 6. Likewise ring 5 is formed with flanges 5a and 5b providing a recess for receiving disc projection 2c also with radial clearance 6. After entry of the disc projection lb into position between ring flanges 4a, 4b, the ring is rigidly secured to the projection by headed pins 1 inserted in corresponding radial holes in the ring inner flange 4b and extending through corresponding holes in the disc projection lb into holes in the ring outer flange 4a. Similarly, ring 5 is rigidly secured to disc projection 20 by pins 8 passing through holes in the ring flanges 5a, 5b and the disc projection 20.

With ring 4 secured as described to disc I, its radial end face remote from the disc registers with spigot on to the corresponding radial end face of ring 5 attached to disc 2. On their outer periphery the rings 4 and 5 are shaped jointly to provide a circumferential recess for the reception of weld metal 9 for rigidly attaching together the rings 4 and 5 and therewith the discs I and 2. It will be appreciated that the weldin operation will be effected while the discs I and 2 are temporarily held tightly together and in coaxial relationship with each other so that the rings 4 and 5 will be firmly held together with their facin radial end surfaces closely engaged.

In similar manner to that just described in respect of the attachment of discs I and 2, the discs I and 3 are rigidly attached together by means of rings l4 and I5 fitting over the disc projections 3b and [0 respectively with radial clearance l6, which rings after being secured to said disc projections by pins l1 and I8 respectively are subsequently welded together at l 9.

With the construction shown and described and subject to the clearance 6, l6 being suitably dimensioned, the discs I, 2 and 3 can be rigidly connected together without introduction of local stresses into the discs during the welding operation.

In the construction specifically shown and described the discs I, 2 and 3 are formed with a central bore l0 for assembly on a shaft. In an alternative construction the discs may be formed without central bores and the outer faces of the two end discs of the rotor are formed each with a projection or projections to which a member may be secured in the manner described above, which members form stub shafts for the bearings. In this construction the disc hubs will be more lightly stressed and may therefore be made narrower than is indicated in the drawing, thus enabling the overall length of the rotor to be reduced.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A rotor for a multi-stage turbine or compressor, comprising a plurality of discs having projections integral therewith and directed from the opposing sides of adjacent discs, annular members mounted on said projections, and a weld securing said members together, said annular members being formed with two axially directed radially spaced annular flanges which receive the projections with clearance between the projections and the radially inner flanges of the respective annular members, and fastening means extending radially through the flanges The attachment f is I to dis 2 i ef e of the annular members and the respective projections and securing the annular members to the respective discs.

2. A rotor for a multi-stage turbine or compressor, comprising a plurality of discs having annular projections integral .with the respective discs and directed toward one another from the opposing side faces of adjacent discs, annular members mounted on the projections on the respective discs, and a weld securing said members together, each of said annular members being formed with two axiall directed radially spaced annular flanges which receive the annular projection on the respective disc with clearance between the projection and the radially inner flange of the respective annular member, and fastening means extending radially through the flanges of each annular member and the respective projection and securing the annular members to the respective discs.

3. .A rotor for a multi-stage turbine or compressor, comprising a plurality of discs each having an annular projection on a side face thereof and integral therewith and directed axially toward the opposing side face of an adjacent disc, an annular member mounted on the projection on one disc, an annular member mounted on the projection on an adjacent disc, and a weld securing the annular members together, each of said annular -members bein formed with two axially directed annular flanges spaced radially to receive the axially directed annular projection on the respective disc with clearance between the radially inner flange of the annular member and the respective projection, and the annular members being formed on their meeting faces one with a surface and the other with a cooperating flange to locate said members concentrically with the discs for welding together.

4. A rotor for a multi-stage turbine or compressor, comprising at least two coaxially arranged discs each having a plurality of projections integral therewith and extending axially therefrom toward the adjacent disc, an annular member secured on the projections on each disc and having two axially directed flanges forming a housing for the respective projections with clearance between each projection and the radially inner of said two flanges of the respective annular member, said annular members bein formed on their meeting faces one with a surface and the other with a flange which cooperate to locate said members and the discs secured thereto concentrically for welding together.

5. A rotor for a multi-stage turbine or compressor, comprising at least two coaxially arranged discs, each of the discs having on the surface thereof which faces the other disc an annular axially directed projection arranged concentrically with the rotor axis and intermediately between said axis and the periphery of the disc, an annular member mounted on each of said projections and having radially inner and radially outer axially projecting flanges forming a space for receiving the respective projection with clearance between the radially inner flange and the projection, and fastening means extending radially through said flanges of each annular member and the respective projection, the meeting surfaces of the annular members of the two discs being provided with cooperating parts which locate said members and the discs secured thereto concentrically with the axis of the rotor, and the radially outer edges of said members adjacent to their meeting surfaces being shaped to provide a recess for receiving weld metal.

KARL BAUMANN.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 1,399,816 Spiers Dec. 13, 1921 2,369,051 Huber Feb. 6, 1945 FOREIGN PATENTS Number Country Date 341,892 Germany Oct. 1921