End-Suction Centrifugal Pump

An end-suction centrifugal pump is a widely utilized rotodynamic pump designed for fluid to enter axially and discharge radially via the impeller. These pumps are known for their simple design, reliability, and cost-effectiveness in processing clean or lightly contaminated water.

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In water and wastewater treatment plants, end-suction centrifugal pumps are favored for applications involving low to moderate flow and pressure conditions. Their robust construction and straightforward maintenance make them an essential component for a variety of utility and process water movements.

• Raw and finished water pumping
• Chemical feed systems (dosing or transfer)
• Booster stations
• Return and Waste Activated Sludge (RAS/WAS) pumping (light sludge, low solids)
• Filter backwash water supply
• General utility water systems
• Secondary water recirculation

• Routine Tasks:
• Check for abnormal noise, vibration, leaks (daily)
• Record/trend pressure, flow, and power data (daily/monthly)
• Lubricate bearings if required (monthly or as specified)
• Inspect and clean strainers/suction screens (monthly)
• Maintenance Activities:
• Inspect and replace shaft seals/gaskets (annually or as needed)
• Overhaul/replace impeller and bearings (annually or as required)
• Check motor alignment/coupling (annually)
• Safety/Troubleshooting:
• Depressurize and lock out before maintenance
• Monitor for cavitation, wear, excessive seal leakage
• Investigate vibration promptly—it can signal imminent failure

• Casing (Pump Body): Contains and directs fluid, houses the impeller; material must resist corrosion and abrasion (cast iron, ductile iron, stainless steel).
• Impeller: Rotating component imparting velocity; open, semi-open, or closed configuration, material chosen by liquid type.
• Shaft and Shaft Seal: Shaft connects impeller and motor; seal prevents leakage (packed gland or mechanical type), selected for pressure, temperature, and liquid features.
• Bearing Assembly: Keeps shaft/impeller aligned and reduces friction; chosen for expected loads and service intervals.
• Pump Base/Frame: Ensures stable, level mounting and proper alignment; must be sturdy to resist vibration.
• Motor (Driver): Typically electric, sometimes engine-driven; size matches pump curve requirements.

• Flow Rate: 20–5,000+ gallons per minute (gpm)
• Total Dynamic Head: 20–200 feet (ft)
• Solids Size: ≤1/8 to 3/8 inch (lightly contaminated water)
• Temperature Range: 40°F–180°F (4°C–80°C)
• Motor Power: 1–200 HP (higher for large units)
• Suction/Discharge Size: 1–12 inches

• Pump Sizing/Selection Software: Xylem Pump-Flo, Grundfos Product Center, KSB EasySelect
• Hydraulic Modeling Tools: EPANET, AFT Fathom, Bentley WaterGEMS
• CAD/BIM Integration: Autodesk Revit, AutoCAD Plant 3D
• CFD Analysis: ANSYS Fluent or similar for advanced flow evaluation

• MasterFormat Division & Section: 43 21 39 – Process Pumps
• Other References: 43 23 00 – Pumps; 43 23 10 – End Suction Pumps (if applicable)

• Grundfos – NB Series End-Suction Pumps
• Xylem (Goulds Water Technology) – 3656/3756 Series
• KSB – Etaline

• Vertical Inline Centrifugal Pump
• Advantage vs. End-Suction: Space-saving with minimized footprint and ability to keep piping vertical.
• Disadvantage vs. End-Suction: More challenging in-line servicing; generally suited for smaller capacities.
• Split-Case Centrifugal Pump
• Advantage: Easier access for internal maintenance on larger units; suitable for higher flows and heads.
• Disadvantage: Higher initial cost and a larger installation footprint.
• Submersible Pump
• Advantage: Installs directly in wet wells, no priming required, quiet, saves floor space.
• Disadvantage: Repairs are more difficult; electrical connections and submergence limit some applications.