Abstract: Mechanical seal leakage of liquid hydrocarbon pumpis a common failure in oil refining and chemicalengineering facilities. In the ployacrylamide unit of Henanoilfield refinery, serious mechanical seal leakage occurs infour types of liquid hydrocarbon pumps. Severaltechnological transformation are performed includingsetting screw covering self-cleaning units and usingthreaded pipe mechanical seal. Evacuation, frosting,vibration and mechanical seal breaking of liquidhydrocarbon pump are eliminated. The working life ofmechanical seal elongates from 1 - 7 days to 6 months,some even to 10 months.