Patent ID: 8257026
Filing Date: 2012-09-04
Classification: F01D,F05D,H02K

Abstract:
1. An expansion turbine comprising: a rotating shaft with a first end and a second end opposite to the first end, and the rotating shaft having an outer periphery; a turbine impeller positioned on the first end of the rotating shaft; magnetic parts positioned and configured to create a difference in magnetic resistance in a circumferential direction of the rotating shaft on the outer periphery of said rotating shaft at the first end and the second end of the rotating shaft; a casing positioned at a location at the outer periphery of said rotating shaft; a coil positioned outside of the casing, the coil positioned and configured to generate a magnetic flux when a current flows; and a magnetic path formed by said coil between said casing and said magnetic parts, wherein said turbine impeller is positioned and configured to rotate when a gas supplied to the turbine impeller is adiabatically expanded, said magnetic path and the rotation of said rotating shaft are positioned and configured to generate eddy currents in the casing; a cooling water path is provided in said casing, the cooling water path has an outer diameter substantially the same as the outer diameter of the coil and is positioned and configured to cool said casing by water circulating through said cooling water path, and said coil is provided outside of said casing separated from said cooling water path by a sealing part made of a nonmagnetic material.