Automobile Manufacturing: Overview of Centrifugal Pumps & Vacuum Pumps

The four major processes of vehicle manufacturing are stamping, welding, painting and final assembly, supplemented by machining/engine workshops, utility power stations and wastewater treatment stations. Centrifugal pumps are used for liquid transportation and circulation; vacuum pumps generate negative pressure (gas evacuation, vacuum adsorption, vacuum filling and leak detection). Both pump types are widely adopted in automobile plants. The painting workshop consumes the largest quantity of centrifugal pumps, while final assembly and component testing are core application scenarios for vacuum pumps.

I. Centrifugal Pumps

Media handled: water, ethylene glycol chilled water, degreasing solution, phosphating solution, electrophoretic paint, cleaning emulsion and wastewater. Common models: IS, IH, CDL vertical multi-stage pumps, magnetic drive pumps, PTFE-lined chemical centrifugal pumps.

Painting Workshop (Largest consumption) Pretreatment line: circulation spray pumps for degreasing, water washing and phosphating bath liquid. Stainless steel / PTFE-lined centrifugal pumps continuously circulate bath liquid to ensure workpiece cleaning and uniform phosphating film. They deliver corrosive media containing chemicals and fine solid residues.

Electrophoresis (Cathodic Electrodeposition, CED): low-speed centrifugal pumps with mechanical seal / magnetic drive are used for electrophoretic paint circulation to avoid paint shear damage, conveying electrophoretic paint to electrophoresis tanks and ultrafiltration systems.

Water curtain circulation for spray booth: circulating water pumps for water curtain cabinets to capture paint mist.

Wastewater station: wastewater lift pumps and chemical dosing pumps. Painting wastewater contains acid, alkali and paint sludge.

Machining / Engine / Gearbox Workshop Circulation delivery of cutting fluid and emulsion, liquid supply for filtration systems; Water supply pumps for high-pressure workpiece cleaning stations.

Utility Power Station (Plant-wide auxiliary system) Chilled water and cooling water circulation pumps (for chillers, central air conditioning and workshop equipment cooling); Plant process water supply and fire water supply; Pure / deionized water transportation (for painting and battery cooling circuits).

Operating characteristics of centrifugal pumps: Most run continuously for 24 hours. Media in painting workshops are corrosive and contain fine solid particles. Material selection (304/316 stainless steel, PTFE lining), mechanical seal and particle wear resistance are key selection factors.

II. Vacuum Pumps

Main types: liquid ring vacuum pumps (2BV/2BE, most common, resistant to water vapor), rotary vane vacuum pumps and dry screw vacuum pumps, selected according to vacuum degree and media.

Final Assembly Workshop (Core application) Vacuum filling of brake fluid: evacuate and leak-test vehicle brake pipelines before filling brake fluid. Air in pipelines must be fully removed to guarantee braking safety.

Air conditioning refrigerant circuit: evacuate moisture and conduct leak test before refrigerant filling; vacuum evacuation and coolant filling for thermal management circuits of new energy vehicles.

Vacuum filling of power steering oil.

Welding / Stamping Workshop Vacuum suction grippers for manipulators: grip steel sheets, vehicle doors, sunroofs and windshields. Central vacuum stations (liquid ring / rotary vane vacuum pumps) provide negative pressure source for robot loading and unloading, widely used on welding lines.

Component Manufacturing & Testing Vacuum impregnation for castings: seal micro-pores of aluminum castings for cylinder blocks and cylinder heads to prevent leakage.

Helium leak detection: air tightness test for fuel pipelines, cooling circuits, motor housings and battery housings.

Vacuum thermoforming of interior parts: plastic forming for instrument panels, door panels and headliners.

Engine bench test: vacuum extraction for engine test benches.

Auxiliary Painting Process Vacuum drying and solvent recovery, removing solvent from high-solvent paint films.

Key selection rules for vacuum pumps: Media with water vapor, solvent vapor and slight condensable gas → liquid ring vacuum pump 2BV/2BE (most popular in auto plants); High cleanliness, oil-free and water-free environment → dry screw pump; High-vacuum leak detection and precision filling → rotary vane pump.