Patent ID: 8529234

Claim:
A water injection type screw fluid machine, in which a target gas is compressed or expansion force of the target gas is converted into turning force by intermeshing male and female screw rotors housed in a rotor chamber formed in a casing, while water is injected inside the rotor chamber to lubricate the screw rotors, the screw fluid machine comprising: a first non-contact seal, a second non-contact seal, and a lip seal, which are disposed between the rotor chamber and a bearing for a rotor shaft of the screw rotor and in this order from the rotor chamber side; a pressurized communicating channel for introducing the target gas which is at high pressure into a pressurized space formed between said first non-contact seal and said second non-contact seal; and an open communicating channel, through which an open space, which is formed between said second non-contact seal and said lip seal, opens to an outside of the casing.