Centrifugal turbomachine with two stages arranged back-to-back and with an annular transfer duct between the stages

Abstract

The turbomachine assembly includes a first turbomachine having an inlet, an outlet and a rotary shaft, a second turbomachine having an inlet, an outlet and a rotary shaft, a transfer duct fluidly connecting the outlet of the first turbomachine to the inlet of the second turbomachine, and a casing housing the turbomachines and the transfer duct; the turbomachines are located adjacent to each other so that the outlet of the second turbomachine is close to the outlet of the first turbomachine and the inlet of the second turbomachine is remote from the outlet of the first turbomachine; the outlet of the second turbomachine has an end portion shaped like a cochlea (i.e. a spiral duct); the transfer duct has an annular shape, and surrounds the end portion of the outlet of the second turbomachine.

1 . A turbomachine assembly comprising:
 a first turbomachinc having an inlet, an outlet and a rotary shaft,   a second turbomachine having an inlet, an outlet and a rotary shaft,   a transfer duct fluidly connecting the outlet of the first turbomachine to the inlet of the second turbomachine, and   a casing housing the first turbomachine and the second turbomachine and the transfer duct;
 wherein the first turbomachine and the second turbomachine are located adjacent to each other so that the outlet of the second turbomachine is close to the outlet of the first turbomachine and the inlet of the second turbomachine is remote from the outlet of the first turbomachine; 
 wherein the outlet of the second turbomachine has an end portion shaped like a cochlea; and 
 wherein the transfer duct has an annular shape, and surrounds the end portion of the outlet of the second turbomachine. 
   
     
     
         2 . The turbomachine assembly of  claim 1 , wherein the transfer duct develops at the beginning at least partially radially and/or in the middle substantially axially and/or at the end at least partially radially. 
     
     
         3 . The turbomachine assembly of  claim 1 , wherein the transfer duct develops as a mantle around the second turbomachine starting at the outlet of the second turbomachine and ending at the inlet of the second turbomachine. 
     
     
         4 . The turbomachine assembly of  claim 1 , further comprising an outlet duct protruding from the casing;
 wherein the end portion of the outlet of the second turbomachine is fluidly connected to the outlet duct of the assembly through a connection duct; and   wherein the connection duct passes through the transfer duct.   
     
     
         5 . The turbomachine assembly of  claim 1 ,
 wherein the transfer duct surrounds completely the second turbomachine.   
     
     
         6 . The turbomachine assembly of  claim 1 ,
 wherein the transfer duct comprises:   a first end portion directly fluidly connected to the outlet of the first turbomachine, and   a second end portion directly fluidly connected to the inlet of the second turbomachine.   
     
     
         7 . The turbomachine assembly of  claim 6 ,
 wherein the area of the cross-section of the transfer duct increases along the first end portion.   
     
     
         8 . The turbomachine assembly of  claim 6 ,
 wherein the distance between the transfer duct and an axis the shaft of the second machine increases along the first end portion.   
     
     
         9 . The turbomachine assembly of  claim 1 ,
 wherein the first turbomachine is a first compressor or first pump:   wherein the second turbomachine is a second compressor or second pump;and   wherein the rotary shafts of the first turbomachine and the second turbomachine are mechanically coupled together.   
     
     
         10 . The turbomachine assembly of  claim 1 ,
 wherein the first turbomachine is a compressor or pump;   wherein the second turbomachine is a turbine; and   wherein the rotary shafts of the first turbomachine and the second turbomachine are mechanically coupled together.   
     
     
         11 . The turbomachine assembly of  claim 1 , being for subsea installation. 
     
     
         12 . A transfer duct, the transfer duct comprising:
 a single duct,   whereine the transfer duct is for fluidly connecting an outlet of a first turbomachine to an inlet of a second turbomachine   wherein the single duct has an annular shape around an axis;   wherein the single duct develops at the beginning at least partially radially, in the middle substantially axially and at the end at least partially radially;   wherein the single duct has one pipe-shaped seat for housing at least partially another duct crossing it; and   wherein the single duct has preferably one or more struts or structural reinforcement.   
     
     
         13 . A method of arranging a first and a second distinct and separate ducts, the first duct being designed for feeding a first fluid in an axial direction and the second duct being designed for feeding a second fluid in a radial direction; comprising:
 providing the first duct configured to be as a single annular duct so to define an internal space,   providing the second duct configured to be as a single spiral duct,   positioning the second duct inside the internal space defined by the first duct, and   prolonging the single spiral duct so to cross the single annular duct.   
     
     
         14 . The transfer duct of  claim 12 , wherein the transfer duct develops as a mantle around the second turbomachine starting at the outlet of the second turbomachine and ending at the inlet of the second turbomachine. 
     
     
         15 . The transfer duct of  claim 12 , futher comprising an outlet duct;
 wherein the end portion of the outlet of the second turbomachine is fluidly connected to the outlet duct of the assembly through a connection duct; and wherein the connection duct passes through the transfer duct.   
     
     
         16 . The transfer duct of  claim 12 , wherein the transfer duct surrounds completely the second turbomachine 
     
     
         17 . The transfer duct of  claim 12 , wherein the transfer duct further comprises:
 a first end portion directly fluidly connected to the outlet of the first turbomachine, and   a second end portion directly fluidly connected to the inlet of the second turbomachine.   
     
     
         18 . The transfer duct of  claim 12 , wherein the first turbomachine is a first compressor or pump; wherein the second turbomachine is a second compressor, pump or turbine; and wherein the rotary shafts of the first turbomachine and the second turbomachine are mechanically coupled together. 
     
     
         19 . The turbomachine assembly of  claim 9 , wherein the first turbomachine is a multistage centrifugal machine and the second turbomachine is a multistage centrifugal machine. 
     
     
         20 . The turbomachine assembly of  claim 10 , wherein the first turbomachine is a multistage centrifugal machine and the second turbomachine is a multistage machine.