Manufacturing of a turbomachine impeller by assembling a plurality of tubular components

Patent metadata

Field	Value
Publication number	US-2017260997-A1
Application number	US-201515323134-A
Country	US
Kind code	A1
Filing date	Jul 2, 2015
Priority date	Jul 4, 2014
Publication date	Sep 14, 2017
Grant date	—

Abstract

A method for manufacturing impellers is described. The method provides for manufacturing a plurality of tubular components, each tubular component forming an inner passage, which is shaped as one of the flow passages of the final impeller. The tubular components are assembled together forming a semi-finished impeller. The semi-finished impeller is provided with annular cavities extending around the rotation axis of the impeller and gaps between adjacent tubular components. The gaps and cavities are filled with metal powder and the semi-finished impeller is subject to hot isostatic pressing, to densify the metal powder and form a monolithic final impeller.

First claim

What is claimed is:

1 . A method for producing an impeller comprising: a disc; a shroud; a plurality of blades between the disc and the shroud; and flow passages between adjacent blades; the method comprising the following steps:
manufacturing a plurality of tubular components, each tubular component forming a respective flow passage of the impeller and having an inlet and an outlet; assembling the tubular components to one another forming a plurality of circularly arranged tubular components around an impeller axis, leaving empty gaps between adjacent tubular components; filling the empty gaps with a powder material; and densifying the powder material in the empty gaps by hot isostatic pressing.

2 . The method of claim 1 , wherein the step of manufacturing the tubular components comprises manufacturing the tubular components by additive manufacturing or hydroforming.

3 . The method of claim 1 , further comprising the steps of forming a shroud skin and a disc skin, the circularly arranged tubular components being located between the disc skin and the shroud skin and connected thereto.

4 . The method of claim 3 , further comprising the steps of:
leaving a first empty cavity between the shroud skin and the tubular components; filling the first empty cavity with a powder material; and densifying the powder material in the first cavity by hot isostatic pressing.

5 . The method of claim 3 , further comprising the steps of:
leaving a second empty cavity between the disc skin and the tubular components; filling the second empty cavity with a powder material; and densifying the powder material in the second cavity by hot isostatic pressing.

6 . The method of claim 3 , further comprising the step of bonding an impeller hub to the disc skin.

7 . The method of claim 6 , wherein the impeller hub and the disc skin are connected to one another by one of diffusion bonding and welding.

8 . The method of claim 4 , wherein at least one of the shroud skin and the disc skin is formed from a monolithic workpiece.

9 . The method of claim 3 , wherein the step of forming the shroud skin comprises the steps of manufacturing a plurality of shroud skin segments and connecting the shroud skin segments to one another.

10 . The method of claim 9 , wherein the shroud skin segments are manufactured by additive manufacturing.

11 . The method of claim 3 , wherein the step of forming the disc skin comprises the step of manufacturing a plurality of disc skin segments and connecting the disc skin segments to one another.

12 . The method of claim 11 , wherein the disc skin segments are manufactured by additive manufacturing.

13 . The method of claim 1 , wherein the step of manufacturing each tubular component comprises the step of simultaneously forming at least one of a shroud segment and a disc segment as a single piece with the respective tubular component; and further comprising the step of forming at least one of an impeller shroud and an impeller disc by assembling the tubular components to one another.

14 . The method of claim 13 , wherein:
an empty cavity is formed between each tubular component and the at least one of the disc segment and the shroud segment; at least one empty annular cavity is formed by assembling the tubular components to one another, the at least one empty annular cavity arranged between the tubular components and a shroud skin formed by the shroud segments, or between the tubular components and a disc skin formed by the disc segments; the empty annular cavity is filled with powder material; and the powder material in the annular cavity is densified by hot isostatic pressing.

15 . The method of claim 13 , wherein each disc segment comprises a hub segment.

16 . The method of claim 15 , wherein the hub segment comprises an empty volume surrounded by a skin.

17 . The method of claim 16 , wherein:
an empty annular cavity is formed in a hub portion of the impeller by assembling the tubular components and the respective disc segments to one another; the empty annular cavity is filled with powder material; and the powder material in the annular cavity is densified by hot isostatic pressing.

18 . A method for producing an impeller comprising a disc, a shroud, a plurality of blades between the disc and the shroud, and flow passages formed between adjacent blades; the method comprises the following steps:
manufacturing a plurality of impeller segments, each impeller segment comprised of: a tubular component having an inlet and an outlet and forming a respective flow passage between blades of the impeller; a shroud segment; and a disc segment; assembling and joining the impeller segments to one another, leaving empty gaps between tubular components of adjacent impeller segments; filling the empty gaps with a powder material; and densifying the powder material in the spaces by hot isostatic pressing.

19 . The method of claim 18 , wherein each impeller segment comprises an empty volume in the respective disc segment, the empty volumes of the disc segments forming an empty annular cavity once the impeller segments are assembled and joined to one another; and wherein the empty annular cavity is filled with powder material, which is densified by hot isostatic pressing.

20 . The method of claim 18 , wherein each impeller segment comprises an empty volume in the respective shroud segment, the empty volumes of the shroud segments forming an empty annular cavity once the impeller segments are assembled and joined to one another; and wherein the empty annular cavity is filled with powder material, which is densified by hot isostatic pressing.

21 . An impeller comprising: a disc; a shroud; a plurality of blades between the disc and the shroud; and flow passages between adjacent blades;
wherein each blade comprises an inner core of densified powder material connecting skin portions of the blade, the skin portions forming a suction side and a pressure side of the respective blade.

22 . An impeller according to claim 21 , wherein an inner volume between the flow passages and a shroud skin is filled with densified powder material connecting the shroud skin to the blades.

23 . An impeller according to claim 21 , wherein an inner volume between the flow passages and a disk skin is filled with densified powder material connecting the disk skin to the blades.

Assignees

• Nuovo Pignone Srl
• Nuovo Pignon SrI

Inventors

• Mola Paolo
• Masi Gabriele
• Patel Mihirkumar Pravinbhai
• Tognarelli Leonardo
• Iozzelli Federico

Classifications

• F01D5/048

  Form or construction · CPC title

• B22F5/04

  of turbine blades · CPC title

• B22F5/009

  of turbine components other than turbine blades (of turbine blades B22F5/04) · CPC title

• F04D29/023

  especially adapted for elastic fluid pumps · CPC title

• F04D29/30

  Vanes · CPC title