impelleri

An impeller is the rotating element of pumps, compressors, turbines, and some engines that transfers energy from a driving mechanism to the fluid. As the impeller spins, it accelerates the fluid, creating higher velocity and pressure. The device operates on fluid dynamics principles that convert mechanical energy into fluid energy.

Most impellers are centrifugal or axial. Centrifugal impellers push fluid outward from the center using radial blades and are commonly shrouded (closed) or open (unshrouded). Axial impellers move fluid parallel to the shaft and are used in high-flow, relatively low-pressure applications. Blade shapes may be backward-curved, forward-curved, or radial, affecting efficiency and operating range.

Construction: Impellers have a hub, a set of blades or vanes, and an inlet eye. They can be monolithic or mounted to a shaft. Materials include stainless steel, cast aluminum, bronze, or engineering plastics; high-temperature or corrosive environments require special alloys. Manufacturing methods include casting, forging, or machining. Proper balancing minimizes vibration and prolongs service life.

Applications: Impellers are used in water supply, irrigation, industrial and process pumps, HVAC systems, automotive turbochargers, and broader turbomachinery such as compressors and turbines. In pumps, they determine flow rate and head; in turbines, they extract energy from the fluid.

Performance and maintenance: Design influences efficiency, head, and cavitation risk; improper net positive suction head (NPSH) can cause cavitation. Clearances, wear, and corrosion affect life. Routine inspection, balancing, and alignment are recommended; damaged impellers are typically replaced to restore performance and avoid further damage.