Gas expander system

Abstract

A gas expander system suitable for use in a turbomachine, the gas expander system comprising: a gas expander provided with a moveable part; a magnetic gear arrangement; and a shaft; the moveable part of the gas expander being connectable to a load via the magnetic gear arrangement and the shaft, and movement of the moveable part of the gas expander being arranged to cause movement of the shaft, wherein the magnetic gear arrangement is used in a closed loop heat recovery system, with the inner and outer rotors of the magnetic gear separated by a wall that contains the stator.

1 . A turbocharger system comprising:
 a turbocharger, comprising a turbine and a compressor;   a gas expander system comprising:   a gas expander provided with a moveable part;   a magnetic gear arrangement; and   a shaft;   the moveable part of the gas expander being connectable to a load via the magnetic gear arrangement and the shaft, and movement of the moveable part of the gas expander being arranged to cause movement of the shaft,   wherein the turbocharger system comprises a source of heat arranged to heat a working fluid provided in a closed-loop system to cause expansion of that working fluid to move the moveable part of the gas expander   wherein the magnetic gear comprises a first rotor and a second rotor, the first rotor and second rotor being separated from one another by at least a part of a wall forming part of the closed loop system.   
     
     
         2 . The system of  claim 1  wherein the at least a part of a wall forming part of the closed loop system that separates the first rotor from the second rotor comprises a stator of the magnetic gear. 
     
     
         3 . The system of  claim 1  wherein the wall encloses the closed loop system. 
     
     
         4 . The system of  claim 1  wherein the source of heat is provided by a part of the turbocharger system, an engine to which the turbocharger is connected, or a fluid flowing into or out of the turbocharger or the engine. 
     
     
         5 . The system of  claim 1  wherein the moveable part of the gas expander is located within the closed loop system. 
     
     
         6 . The system of  claim 2 , wherein the system is arranged such that a gas flowing into or out of the turbocharger or the gas expander is arranged to cause movement of the moveable part of the gas expander. 
     
     
         7 . The system of  claim 1 , wherein the first rotor, second rotor and stator each have a substantially cylindrical shape. 
     
     
         8 . The system of  claim 1 , wherein the first rotor, second rotor and stator each have a substantially disc-like shape. 
     
     
         9 . The system of  claim 1 , wherein the first rotor and second rotor each comprises a plurality of permanent magnets. 
     
     
         10 . The system of  claim 1  wherein the magnetic gear member comprises a plurality of pole pieces. 
     
     
         11 . The system of  claim 1  wherein the moveable part of the gas expander system is rotatable. 
     
     
         12 . The system of  claim 1 , wherein the shaft of the gas expander system is rotatable. 
     
     
         13 . The system of  claim 1 , wherein the gas expander is one of a group comprising: a turbine, a piston-type expander, a swash-plate type expander, or a screw-type expander. 
     
     
         14 . The system of  claim 1 , wherein the moveable part of the gas expander is connected to a first rotor of the magnetic gear by a first shaft, and a second rotor of the magnetic gear is connectable to the load via a second shaft. 
     
     
         15 . The system of  claim 1  wherein the load comprises one of a group comprising: an electricity generator; a hydraulic system; a mechanical transmission; a mechanical gear; an engine crankshaft. 
     
     
         16 . The system of  claim 1  wherein the gas expander is a turbine, the moveable part of the gas expander is a turbine wheel, the gas expander forming part of a turbocharger, and wherein the system further comprises the load, the load being a compressor wheel of the turbocharger. 
     
     
         17 . A turbocharger system comprising:
 a turbocharger, comprising a turbine and a compressor;   a gas expander system comprising:   a gas expander provided with a moveable part;   a magnetic gear arrangement; and   a shaft;   the moveable part of the gas expander being connectable to a load via the magnetic gear arrangement and the shaft, and movement of the moveable part of the gas expander being arranged to cause movement of the shaft   wherein the magnetic gear arrangement comprises a first rotor, a second rotor, and a magnetic gear member located in-between the first rotor and the second rotor, the magnetic gear member comprises a first part of the magnetic gear member and a second part of the magnetic gear member that are rotatable relative to each other, one or both of the first part of the magnetic gear member and second part of the magnetic gear member are rotatable relative to the other magnetic gear member respectively from a first position to a second position, the first position being such that magnetic flux is prevented from passing from the first rotor to the second rotor, or from the second rotor to the first rotor, and the second position being such that magnetic flux is allowed to pass from the first rotor to the second rotor, or from the second rotor to the first rotor.   
     
     
         18 . A turbocharger system according to  claim 17  wherein the first part of the magnetic gear member and the second part of the magnetic gear member are concentrically arranged. 
     
     
         19 . A turbocharger system according to  claim 17  wherein the first rotor and second rotor each comprises a plurality of permanent magnets. 
     
     
         20 . A turbocharger system according to  claim 17  wherein the first and second parts of the magnetic gear member each comprise a plurality of pole pieces.