Rotary machine system

A rotary machine system comprising:

• a rotary machine comprising a gas seal portion;
• a gas seal device connected to the rotary machine and that supplies a seal gas to the gas seal portion;
• a pressure sensor that detects a pressure of the seal gas;
• a vent portion that discharges the seal gas discharged from the gas seal portion to the outside;
• and
• a vent pressure sensor that detects a pressure in the vent portion,
• wherein the rotary machine comprises:
• a casing through which a working fluid flows;
• a rotatable rotary shaft that passes through an inside and an outside of the casing;
• and
• the gas seal portion provided between the casing and the rotary shaft and that seals the working fluid by the seal gas having a pressure higher than a pressure of the working fluid in the casing,
• the gas seal device comprises:
• a pressure regulating valve that adjusts the pressure of the seal gas supplied to the gas seal portion;
• and
• a control part that controls the pressure regulating valve,
• the pressure sensor is provided closer to the gas seal portion side than the gas seal device,
• pressure variations occurs in the vent portion, and
• the control part controls the pressure regulating valve according to the pressure of the seal gas detected by the pressure sensor and controls the pressure regulating valve so that the pressure of the seal gas detected by the pressure sensor is higher than the pressure in the vent portion detected by the vent pressure sensor.