SULZER High Precision Pump Spare Parts Closed Type Stainless Steel Impeller

Our brand was established to deliver integrated technical solutions in the fluid machinery and engineering sectors. Backed by a complete portfolio of specialized technologies and product lines, we offer clients expert technical consultation, commercial support, and bundled product solutions — from pumps and frequency converters to servo drives, PLC-HMI, industrial control cabinets, motors, mechanical seals and assemblies, couplings, gearboxes, and full-cycle engineering services (overseas on-site 3D scanning reverse molding of pump replacement parts and field equipment debugging by our dispatched engineers internationally).

FLOWSERVE Closed Impeller (also called enclosed or shrouded impeller) is a centrifugal pump impeller with a front shroud and back shroud enclosing the internal vanes. The closed design creates fully enclosed flow passages that maximize hydraulic efficiency by minimizing recirculation losses and preventing fluid bypass between the pressure and suction sides of the impeller. This makes the closed impeller the preferred choice for high-head, high-efficiency applications handling clean or moderately contaminated fluids.

Unlike open or semi-open impellers, the closed impeller has no adjustability for wear — when the wear rings are worn, they are typically replaced rather than adjusted. The enclosed vane arrangement provides better structural rigidity, allowing higher rotational speeds and operating pressures without vane deflection. Common failure modes include wear ring erosion (from abrasive particles in the pumped fluid), vane erosion at the inlet tips, and corrosion pitting in aggressive chemical service.

Our replacement FLOWSERVE closed impellers are manufactured to original hydraulic profiles using FARO 3D laser scanning for reverse engineering. Each impeller is statically and dynamically balanced to ISO 1940 G6.3 or better, with full material and quality certification.

• Hydraulic Accuracy — FARO 3D scan captures precise vane profile, inlet diameter, and shroud geometry; CFD simulation validates head and efficiency curves
• ISO Balancing — Every impeller statically and dynamically balanced to ISO 1940 G6.3 (G2.5 available for high-speed applications)
• Full Material Range — Cast iron to duplex stainless steel; investment casting for precision, sand casting for larger diameters
• Interchangeable Fit — Bore diameter, keyway, and hub dimensions match OEM specifications; drop-in replacement without pump modification
• Wear Ring Fit — Front and rear wear ring seating surfaces machined to correct interference fit per OEM standard
• Vane Profile Options — Standard backward-curved vanes; special profile for non-clog or low-NPSH applications available on request