centrifugalpumpar

Centrifugalpumpar are machines that move liquids by converting mechanical energy from a motor into hydraulic energy through an impeller inside a pump casing. As the impeller spins, it transfers kinetic energy to the fluid; the casing, typically a volute or a diffuser, converts part of this velocity into pressure, producing flow from the suction to the discharge side.

Most centrifugal pumps are single-stage or multistage, and they can use closed, semi-open, or open impellers. Casings are usually volute or diffuser types, with materials chosen for the liquid and operating environment. They are commonly driven by electric motors, but diesel or hydraulic drives are also used. Pumps are classified by flow type as radial (the most common), mixed-flow, or axial-flow, corresponding to different impeller geometries and performance ranges.

Key performance characteristics include the flow rate (Q), head (H), power input, and efficiency (η). A pump curve, typically provided by manufacturers, shows the relationship between Q and H at a given speed. Specific speed is a parameter used to select the appropriate impeller geometry for a desired duty point. Cavitation is a major concern and occurs when local pressure falls below the liquid’s vapor pressure; adequate Net Positive Suction Head (NPSH) must be available. Many centrifugal pumps are not self-priming and require filling before startup, although self-priming or vertical designs exist.

Applications encompass water supply, building services, irrigation, chemical processing, petroleum industries, and wastewater treatment, as well as heating and cooling systems where circulating liquids are needed. Maintenance considerations include seals (mechanical or packing), bearings, wear parts, and corrosion resistance. Common materials include cast iron, ductile iron, stainless steel, and various alloys or plastics, selected for the liquid and operating conditions.