Abstract: Aiming at the frequent failure of double-ended mechanical seals equipped on brine transfer pumps during the operation of low-temperature frozen brine units caused by their inadaptability to on-site working conditions, this paper carries out disassembly analysis and improvement on the failed mechanical seals. The original double-ended mechanical seals are replaced with cartridge single-ended seals to effectively isolate the corrosion of 23% calcium chloride solution. The friction pair materials are upgraded to low-temperature and corrosion-resistant cemented carbide-carbon graphite. The pipe diameter of the cooling system is expanded from DN15 to DN20, and the flushing mode is changed from PLAN14 to PLAN11 self-flushing mode. Verified by field installation and application, the improved cartridge single-ended seals operate stably. The stationary ring and rotating ring form precise sealing end faces, and the spring assembly provides stable end face pressure. The cooling system can efficiently dissipate frictional heat and remove impurities. With rational design and strict maintenance, the mechanical seals achieve long-term zero-leakage operation and enhance production reliability.