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Due to their highly corrosive, toxic, flammable, and explosive properties, chemical raw materials require special specifications for transportation equipment. Chemical pumps can generally be classified as follows based on their working principle and structure: 1. Impeller pumps: These rely on the rotating impeller to exert force on the liquid, transferring energy to it continuously; this increases the liquid’s velocity and pressure, generating centrifugal force. Subsequently, most of the kinetic energy is converted into pressure energy, thereby enabling the transport of the liquid. Impeller pumps include centrifugal pumps, mixed-flow pumps, axial flow pumps, vortex pumps, high-speed pumps, etc. 2. Positive displacement pumps: These are pumps that transfer energy to a liquid by means of periodic changes in the volume of the working chamber, thereby increasing the pressure of the liquid and enabling its transport. They generally include reciprocating pumps, rotor pumps, gear pumps, vane pumps, and screw pumps. 3. Other pumps: Magnetic pumps that use electromagnetic force to transfer fluids (stainless steel magnetic pumps, fluorinated lining magnetic pumps, insulated magnetic pumps, high-temperature magnetic pumps, etc.); jet pumps and air lift pumps that rely on the energy of fluid flow for transportation; as well as water hammer pumps that use the potential energy of the flowing water itself to transfer liquids. Classified by conveying medium: oil pumps, water pumps, impurity pumps, corrosion-resistant pumps. Classified by purpose: 1. Process flow pumps: feed pumps, return pumps, circulation pumps, bottom pumps for towers (vessels), product pumps, flushing pumps, sludge pumps, etc. 2. Utility pumps: including boiler pumps, cooling tower pumps (cooling water pumps, circulation pumps), deep well pumps, sewage pumps, fire pumps, sanitary pumps, etc. 3. Auxiliary pumps: lubricating oil pumps, seal oil pumps, etc. 4. Pipeline transfer pumps: oil pipeline pumps, loading/unloading pumps, etc. Classified by suction method: 1. Single-suction pump: single-suction impeller. 2. Double-suction pump: Double-suction impeller. 3. Classification by the number of impellers: 1. Single-stage pump: one impeller. 2. Multi-stage pump: Two or more impellers on the same shaft. Classified by the generated pressure: 1. Low-pressure pump: total head pressure of 6 MPa. Classified by operating temperature: high-temperature pumps and low-temperature pumps: high temperatures up to 450°C, and low temperatures as low as -253°C. Classified by flow rate: high-flow pumps and low-flow pumps, with flow rates of 300 m3/min and 0.01 L/h respectively. Classified by pump structure: 1. Turbomachine pump: Equipped with guide vanes, which increase pressure by reducing the flow velocity of the liquid. 2. Volute pump: lacks guide vanes, and the discharge side of the impeller features a casing with a volute. 3. Double volute pump: A casing with dual volute chambers on the discharge side of the impeller. 4. Cylindrical pump: A cylindrical pressure-resistant casing is installed outside the inner casing. 5. Double-shell pump: A pump with a double shell, excluding barrel-type pumps.