Process gas delivery equipment in industries such as petroleum, chemical, natural gas and coal oil refining generally uses compressors such as centrifugal compressors and screw compressors. Compressors are high-speed, continuous-operation equipment that is essential for operational safety, reliability and trouble-free operation. Compressor operating conditions depend on the compressor operating conditions parameters, such as pressure, temperature, speed, transmission medium characteristics, sealing systems, etc., of which the choice of sealing system is particularly important. Unocal seals provide shaft seals and systems with excellent sealing performance and high reliability.