Compression device

A compression device comprising:

• a compressor including
• a casing having a rotor chamber,
• a rotor that is housed in the rotor chamber inside the casing and configured to compress gas by rotating,
• a rotor shaft that extends from the rotor,
• a bearing that is provided inside the casing and supports the rotor shaft so that the rotor is rotatable, and
• a first shaft-sealing part and a second shaft-sealing part that are provided to line up between the rotor chamber and the bearing in the casing to seal a periphery of the rotor shaft;
• a first supply line that is adapted to supply injection oil to the rotor chamber;
• a second supply line that is provided independent of the first supply line and adapted to supply lubrication oil to the bearing;
• a third supply line that is adapted to supply sealing gas to the first shaft-sealing part;
• and
• a fourth supply line that is adapted to supply the second shaft-sealing part with sealing oil to be used for sealing at the second shaft-sealing part,
• wherein the fourth supply line branches off from the first supply line and connects to the second shaft-sealing part to supply a part of the injection oil flowing in the first supply line to the second shaft-sealing part as the sealing oil,
• further comprising:
• an opening control valve that is provided to the first supply line at a position that is located further toward an upstream side than a branching point of the fourth supply line is;
• and
• a control unit that controls an opening of the opening control valve so that a pressure of the injection oil in the first supply line is higher than a pressure at an oil inlet port of the rotor chamber and a rotor end part pressure, the oil inlet port being a port that is connected to the first supply line, the rotor end part pressure being a pressure at a rotor-side end part of the rotor shaft.