Patent ID: 8231339

Claim:
An expansion turbine with a variable nozzle mechanism comprising: an adiabatic expansion device located in a vacuum container having a turbine impeller therein, the adiabatic expansion device being configured to produce a drive force to rotate and drive the turbine impeller during adiabatic expansion of very low temperature gas, and to vary a throat area of very low temperature gas introduced in the turbine impeller by driving a nozzle member disposed near the outside end of the adiabatic expansion device by a drive force from a driving member located outside the vacuum container, wherein the driving member comprises a cylindrical member disposed coaxially with the turbine impeller, the nozzle member being located on a first side of a flange member that is provided on an axial end of the body of the cylindrical member, the flange member including an outer flange formed so as to extend outward in a radial direction of the cylindrical member and an inner flange formed so as to extend inward in the radial direction, the outer flange being configured so that the very low temperature gas having high pressure circulates into a second side of the flange member, the second side being opposite the first side of the flange member, and the inner flange being configured so that the very low temperature gas having low pressure circulates into the second side of the flange member.