Working Principle of Centrifugal Pump

Centrifugal pumps are widely used in chemical production due to their compact design, simple operation, and efficient energy conversion. They consist of a high-speed rotating impeller and a stationary volute-shaped pump casing. The impeller, typically with 4 to 12 backward-curved blades, is mounted on the pump shaft and driven by a motor. As it rotates, it imparts kinetic energy to the liquid, increasing its velocity and static pressure.

The pump casing serves two purposes: it collects the liquid flung outward by the impeller and converts its kinetic energy into static pressure energy. A low-pressure zone forms at the impeller's center, drawing liquid in through the suction line, while the liquid exits through the discharge line. To prevent air binding and ensure proper operation, the pump casing must be fully filled with liquid before starting. A one-way foot valve in the suction line prevents liquid from escaping.

Impellers are categorized based on structure (closed, semi-closed, or open), suction type (single-suction or double-suction), and blade geometry (backward-curved, radial, or forward-curved). Backward-curved blades are preferred for their efficiency in converting kinetic energy into static pressure. In some designs, a guide impeller is added to reduce energy loss and enhance pressure conversion.

Shaft seals, including stuffing boxes and mechanical seals, prevent liquid leakage and air entry. Mechanical seals, with rotating and stationary rings pressed together by springs, are ideal for handling corrosive or hazardous liquids. These features make centrifugal pumps reliable and cost-effective for diverse applications.