SCREW EXPANSION MACHINE Russian patent published in 2020 - IPC F01C1/16 

FIELD: machine building; power engineering.

SUBSTANCE: invention relates to the field of power engineering, particularly to the device of screw expansion machines used for the drive of predominantly asynchronous generators. Proposed machine comprises high-pressure housing 1 with inlet branch pipe 2 for supply of high-pressure working medium, low-pressure housing 3 with outlet branch pipe 4 for removal of working medium of low pressure, drive and driven helical rotors. Rotors are equipped with unloading disks 10 arranged in bores 11 of housing 1 to form unloading chambers 12 communicated via channels 13 with branch pipe 4. Cavities of branch pipes 2 and 4 are interconnected by pipeline 18. In pipeline 18 check valve 19 is installed with possibility of its opening at steam pressure in branch pipe 2 less than pressure in branch pipe 4. Valve 19 is located either directly between branch pipes 2 and 4, or from side of channels 13 of discharge cavities 12 of housing 1 with branch pipe 4.

EFFECT: invention is aimed at reduction of mechanical overloads on drive shaft, reduction of value of electric power consumed by generator, changing into motor mode, and improvement of reliability of machine operation during emergency shutdown.

1 cl, 3 dwg