US2461402A - Rotor for multistage axial flow compressors and turbines - Google Patents

Description

1949. L T. WHITEHEAD ROTOR FOR MULTISTAGE AXIAL FLOW COMPRESSORS AND TURBINES Filed Oct. 1945 r l l I l l l l l I l l l l l l l a modification.

Patented Feb., 8, 1949 UNITED STA PATENT OFFICE ROTOR FOR MULTISTAGE AXIAL FLOW COMPRESSORS AND 'TURBINES Leslie Thomas Whitehead, Farnborough, England,

assignor to Power Jets (Research'and Development) Ltd., London, England, a British company Application October 5, 1945, Serial No. 620,503 In Great Britain October 6, 1944 8 Claims. (Cl. 230-434) g f l 2 This invention relates to rotors for multi-stage employment of spacers between ,blades' of adaxial flow compressors and turbines. .iacent rows; g I a It is usual to provide multi-stage compressors Figure 4 is 'a section. taken 'alon g tli e-line .,44

of the axial flow type with a rotor comprising of Figure 2. I e either a hollow drum or a plurality of solid discs. Referring to the embodiment shown in Fig.

With the drum type rotor the maximum cen- 1, the drum comprisesa seriesof s'oliddiscs l trifugal stress is approximately twice that in a each of which increasesinthiclgnesstoward the solid disc of uniform thickness for the same'rim centre and. is formed integrallyswithwrimflanges speed. If the disc is bored for a central shaft, 2, 3 which extend one toieachnsid'eo hefldisc. the stress approaches that of a hollow drum 10 The discs I are arranged coeaxiallya unless the disc thickness is increased toward the posed rim flanges 2, ll of: adjace centre, thereby increasing the Weight. Also, adapted to be passed into overl when calculating whirling speed for a disc rotor ment and to be secured togetne the shaft diameter is used and not the rim dithreads [as shown. Thus, a ameter; this results in a much lower critical clearly'in Fig. 2, the rim-.-fiange v v speed than for a drum rotor with similar bear- 1 arescrewthreaded.oneinternally n, the

ing centres. externally, to mate witneomplmentar Now the object of the present invention is to threaded rim flanges of adjacent discswl. In provide a multi-stage rotor of simplified conthisconnection the'flanges 2,-3-"are'stepped or struction which will have the advantages of the 20 rebatcd, one internally and the other. externally, solid disc, so far as centrifugal stress is conand" the screwthreads larecutfin the circumcerned, and of the hollow druminsofar as it .ferential surfaces of therebatesaand-extend over has a comparatively high critical speed and large effective diameter.

According to the invention, the multi-stage axial flow compressor or turbine rotor comprises a plurality of solid discs which are coaxially arranged and are directly interconnected at their rims so that the latter jointly afford the equivalent of a hollow drum blading being secured in'axial grooves in the drum-like assembly and elements in the axial grooves extending across the joints between the discs Which are thereby 3 locked against relative rotation. vThe elements; extending across the joints may be in the form, of spacers between the blade roots or the blade roots themselves may serve as such elements} In order that the invention may be clearly; I': I understood and readily carried into effect,'the;.; v I ,7 r same will now be more fullyde'scribed with ref into ,.fanother, advantage'may L'beI-t'aken of the erence to and by the aid of the accompanying" Working temperature 'differenceibetween stages. drawings, in which-,- x or thetemperature drop along the rotor, by ar- Fig. 1 is a diametrical section of the rotor ranging that the internally threaded rim flange drum of a multi-stage axial flow compressor g of a cooler disc overlaps more outside the (or turbine) constructed according to one emf- 5 externallythreaded flange of ahotter disc, therebodiment'of the invention by ensuringthat-any differential expansion will Fig. 2 is a fragmentary section, on an en'- tend to.keep'the'screW-threadjoint. tight. larged scale, illustrating moreclearly the man- Assern'bl' th'e discv elements to constitute a ner in which the rims of adjacent disc elements combined-disc and drum rotor would; be effected of the rotor drum are mated and secured tobefore finally machining the outer diameter and gether. r 'cu tting thebladegrooves. Each disc I may Fig. 3 is a similar view toFig."2but illustrating' carry a circumferential row of radially disposed I 'j'b1ades;5 as zshown, mounted in serrated axially Figs. 2 and 3 also illustrate the mounting of f disposed-grooves, said grooves, indicated at 6, the blades in axially disposed groovesandthe 55 may'becut throughout the length of therotor the whole of the ilength. thereof; Alternatively, as showngin 3, lon l y"a part, flgthfi "sembiing the multijstage'jfrotor by he: rim flanges ofv adjacent-"discs one drum and the blades of adjacent rows be located by serrated spacers I inserted in said grooves 6 and arranged to bridge the screwed joints between adjacent disc elements so as to constitute keys locking the rims of adjacent discs together against relative rotation or unscrewing.

In Fig. 1 an axially disposed shaft coupling 8 is mounted on one of the end discs 01! the composite rotor and a hollow shaft extension is screwed into the outermost rim flange 2 of the other end disc.

It will, of course, be understood that whereas in the embodiments illustrated the serrated type of blade root fixing is shown, the sides of the blade roots and of the intermediate spacers I being serrated to cooperate with complementary or corresponding serrated side walls of the grooves 6, any other conventional or convenient method of blade fixing and locating may be employed in conjunction with axial grooves in the rotor.

What I claim as my invention and desire to secure by Letters Patent is:

1. A rotor for a muiti-stage axial flow turbomachine, comprising in combination, a series of solid discs arranged coaxially with their rims abutting and jointly afiording the equivalent of a hollow drum, blading secured in axial grooves in said drum-like assembly of inter-connected discs, and elements in said grooves extending .solid discs arranged coaxially and formed integrally with rim flanges on opposite sides, the opposed rim flanges of adjacent discs being secured together in overlapped engagement, blading secured in axial grooves in said discs, and elements in said grooves extending across the joints between said discs thereby locking said discs against relative rotation.

3. A rotor for a multi-stage axial flow turbomachine comprising in combination a series of solid discs arranged coaxially and formed on opposite sides with integral rim flanges which are screw-threaded, one internally and the other externally, the opposed rim flanges of adjacent discs being secured together in overlapped engagement by screwing one into the other, blading secured in axial grooves in the rims of said discs, and elements in said grooves extending across the joints between said discs thereby looking said discs against relative rotation.

4. A rotor for a multi-stage axial flow turbomachine, comprising in combination a series of solid discs arranged coaxially and formed on opposite sides with integral rim flanges which are rebated, one internally and the other externally, the circumferential surfaces of the rebates being screw-threaded, the opposed rim flanges of adjacent discs being secured together in overlapped engagement by screwing one into the other, blading secured in axial grooves in the rims of said discs, and elements in said grooves extending across the joints between said discs thereby locking said discs against relative rotation.

5. A rotor for a multi-stage axial flow turbomachine, comprising in combination a series of solid discs arranged coaxially and formed on opposite sides with integral rim flanges which are rebated, one internally and the other externally. portions of the circumferential surfaces of the rebates being screw-threaded, the opposed rim flanges of adjacent discs being secured together in overlapped engagement by screwing the externally threaded -portion of one into the internally threaded portion of the other with the plain portions of the rebates mating to afford spigot and socket connections, blading secured in axial grooves in the rims of said discs, and elements in said grooves extending across the joints between said discs thereby locking said discs against relative rotation and at the same time spacing said blading.

6. A rotor for a multi-stage axial flow turbomachine, comprising in combination a series of solid discs arranged coaxially and formed on opposite sides with integral rim flanges which are screw-threaded, one internally and the other externally, the opposed rim flanges of adjacent discs being secured together in overlapped engagement by screwing one into the other, radially disposed blades mounted in serrated axial grooves in the assembly of disc rims and arranged in circumferential rows, and serrated spacers in said axial grooves between and locating said blades and bridging the screwed joints between adjacent disc rims, said spacers thereby constituting keys which lock the rims of the discs against relative rotation.

7. A rotor for a multi-stage axial flow. turbomachine, comprising in combination a series of solid discs arranged coaxially and formed integrally with rim flanges on opposite sides, the opposed rim flanges of adjacent discs being secured together in overlapped engagement with the rim flanges of a cooler disc overlapping on the outside the rim flange of the adjacent hotter disc, whereby any difierential expansion keeps the joint between the overlapped flanges tight, blading secured in axial grooves in the rims of the said discs, and elements in said grooves extending across the joints between said discs, thereby locking said discs against relative rotation.

8. A rotor for a-multi-stage axial flow turbomachine, comprising in combination a series of solid discs arranged coaxially and formed on opposite sides with integral rim flanges which are screw-threaded, one internally and the other externally, the opposed rim flanges of adjacent discs being secured together in overlapped engagement by screwing one into the other, the internally threaded rim flange of a cooler disc overlapping the externally threaded rim flange of the adjacent hotter disc whereby any differential expansion keeps the screw-threaded joint tight, blading secured in axial grooves in the rims of said discs, and elements in said grooves extending across the joints between said discs thereby locking said discs against relative rotation.

LESLIE THOMAS WHITEHEAD.

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

FOREHGN PATENTS Number Country Date 352.282 Germany Apr. 24, 1922 383,252 Great Britain Nov. 10, 1932 394,001 Great Britain June 19, 1933 543,985 Great Britain Mar. 23. 1942

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