摘要 |
A screw expander in which a pair of male and female screw rotors engaged with each other are housed in a rotor chamber formed in a casing, an expansion force of a high-pressure gas supplied from an intake flow path to the rotor chamber is converted into a rotational force by the screw rotors and the expanded low-pressure gas is exhausted to an exhaust flow path includes a valve mechanism capable of allowing communication between an intermediate pressure portion, which is a space in the rotor chamber and can be separated from the intake flow path and the exhaust flow path by the screw rotors, and a bypass flow path, to which a high-pressure gas is supplied, and a controller for controlling the valve mechanism in accordance with an operation expansion ratio which is a ratio of a pressure in the intake flow path to a pressure in the exhaust flow path. |