Sealing system

A sealing system for sealing a rotational shaft of a centrifugal pump, comprising:

• a double mechanical seal having a pump-side sealing mechanism and an atmospheric-side sealing mechanism;
• a pump mechanism driven by the rotational shaft, the pump mechanism being located between the pump-side sealing mechanism and the atmospheric-side sealing mechanism;
• a first chamber defined by at least the atmospheric-side sealing mechanism and the pump mechanism;
• a second chamber defined by at least the pump-side sealing mechanism and the pump mechanism;
• a first medium circulation line for circulating a fluid barrier-and-cooling medium between the first chamber and the second chamber, the first medium circulation line being coupled to the first chamber and the second chamber, the fluid barrier-and-cooling medium being different from a fluid handled by the centrifugal pump;
• a heat exchanger and a shut-off valve attached to the first medium circulation line;
• a second medium circulation line having both ends coupled to the first medium circulation line, the second medium circulation line bypassing the shut-off valve;
• and
• a medium pressurizing pump and an on-off valve attached to the second medium circulation line.