# US 12,215,708 B2 · Turbomachine rotor with stacked impellers and turbomachine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,215,708 B2 - Document ID: US12215708B2 - Status: Granted - Kind: B2 - Application number: 18/556,607 - Filed: 2022-04-25 - Published: 2024-06-20 - Granted: 2025-02-04 - Earliest claimed: 2021-04-28 - Assignees: Nuovo Pignone Tecnologie Srl - Applicants: Nuovo Pignone Tecnologie—S.R.L. - Inventors: Francesco Cangioli; Alberto Guglielmo; Giuseppe Vannini; Marco Formichini; Massimiliano Tempestini; Dario Matina - Web page: https://patentgrep.com/patent/US12215708B2 ## CPC - F04D 29/053: Shafts - F04D 29/286: {multi-stage rotors} - F01D 5/04: for radial-flow machines or engines - F01D 5/066: {Connecting means for joining rotor-discs or rotor-elements together, e.g. by a central bolt, by clamps} - F01D 25/164: {Flexible supports; Vibration damping means associated with the bearing} - F04D 17/122: {the individual rotor discs being, one for each stage, on a common shaft and axially spaced, e.g. conventional centrifugal multi- stage compressors} - F04D 29/054: Arrangements for joining or assembling shafts - F04D 29/668: {damping or preventing mechanical vibrations} - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) ## Abstract The rotor comprises a plurality of rotor segments arranged axially adjacent to one another. A tie rod extends through the rotor segments. Opposed first and second locking members arranged at the axial ends of the tie rod lock the rotor segments to one another and to the tie rod. At least one intermediate support member is arranged in an intermediate position between the two axial ends of the tie rod and between the tie rod and one of the rotor segments. ## Claims ### Claim 1 A rotor for a turbomachine, comprising: a plurality of rotor segments arranged axially adjacent to one another, each rotor segment including a central through bore; a tie rod extending through the through bores of the rotor segments, the tie rod having opposite first axial end and second axial end; a first stub shaft and a second stub shaft arranged at the first axial end and second axial end of the tie rod, each coupled to the tie rod so as to lock the rotor segments to one another and to the tie rod; and at least one intermediate support member arranged in an intermediate position between the first axial end and the second axial end of the tie rod and between the tie rod and one of the rotor segments; wherein the intermediate support member comprises an inner annular component coupled to the tie rod and rotating therewith, and an outer annular component adapted to co-act with said one rotor segment; wherein the outer annular component comprises a plurality of annular segments, each annular segment being coupled to the inner annular component by at least one resilient member arranged between the inner annular component and the annular segment; and wherein the inner annular component, the annular segments of the outer annular component and the resilient members are formed as a monolithic machine component, wherein at rest, the outer diameter of the outer annular component is smaller than an inner diameter of a bore of the rotor segment, in which the intermediate support member is housed, wherein when the rotor is driven into rotation, the annular segments expand under the effect of centrifugal force acting thereon and provide an intermediate support constraint for the tie rod, causing a stiffening thereof and a consequent increase of the first resonant frequency of the tie rod, and wherein the characteristics of the resilient members are such that the annular segments engage with the bore of the rotor segment at a rotational speed equal to or lower than 70% of the nominal rotational speed of the rotor. ### Claim 2 (depends on 1) The rotor of claim 1, wherein each annular segment is mechanically decoupled from the adjacent annular segments. ### Claim 3 (depends on 1) The rotor of claim 1, wherein the inner annular component and the annular segments are formed as a single body by additive manufacturing. ### Claim 4 (depends on 1) The rotor of claim 1, wherein the tie rod comprises an intermediate section, a first side section extending from the first axial end to the intermediate section and a second side section extending from the second axial end to the intermediate section; wherein the intermediate section has a diameter larger than a diameter of at least one of said first side section and second side section and the at least one intermediate support member being locked to the tie rod at said intermediate section. ### Claim 5 (depends on 1) The rotor of claim 1, wherein the rotor segments include centrifugal compressor impellers, and wherein the intermediate support member is arranged in a central through bore of one of said centrifugal compressor impellers. ### Claim 6 (depends on 1) The rotor of claim 1, wherein the rotor segments include a first set of centrifugal compressor impellers and a second set of centrifugal compressor impellers; wherein the first set of centrifugal compressor impellers and the second set of centrifugal compressor impellers are arranged in a back-to-back configuration; wherein the rotor segments further include an interphase drum arranged between the first set of centrifugal compressor impellers and the second set of centrifugal compressor impellers; and wherein the intermediate support member is arranged in a central through bore of the interphase drum. ### Claim 7 (depends on 1) The rotor of claim 1, further comprising a first stub shaft at the first axial end of the tie rod and a second stub shaft at the second axial end of the tie rod. ### Claim 8 (depends on 1) A turbomachine including a casing and a rotor according to claim 1, arranged for rotation in the casing. ### Claim 9 (depends on 8) The turbomachine of claim 8, wherein the turbomachine is a compressor. ### Claim 10 (depends on 8) The turbomachine of claim 8, wherein the turbomachine is a centrifugal compressor.