Centrifugal compressor and dry gas seal system for use in it

摘要

The present invention relates to a centrifugal compressor using a dry gas seal system for protecting seal means. A multistage centrifugal compressor has primary dry gas seal means for preventing leakage of working gas from a machine inner side, and secondary dry gas seal means for backing up the first dry gas seal means. A seal gas line for introducing the gas leaked from the first and second dry gas seal means to the outside of the machine is installed between the primary dry gas seal means and the secondary dry gas seal means. The gas seal line has an orifice and a check valve, and buffer means is installed between the orifice and the check valve.