YLB type submersible pumps (liquid sulfur pumps) are mainly used in refineries, petrochemical industry, coal chemical industry, sulfur recovery units, power plants, environmental protection projects, sewage treatment and other fields. It is suitable for transporting various clean mediums without particles or with a small amount of particles such as slurry, sewage, dirty oil and liquid sulphur, etc. The design and manufacture of this type of pump fully comply with the relevant requirements of the VS4 type pump in the 11th edition of API610. Its structure is a single-stage, single-suction, volute-type vertical long-axis submersible pump; the liquid sulfur pump is equipped with an insulation jacket. This series of pumps has high safety and reliability, stable pump operation, long service life, simple and convenient maintenance, strong parts versatility and few types of spare parts. This series of pumps are designed with flexible shaft design theory. The pump shaft adopts a reliable shaft connection method and a multi-point support structure with maximum insertion.