Heavy Duty Pump

Heavy duty means different things to different people.

My definition is, “A pump that can operate in a wide operating window without breaking something or experiencing premature seal and bearing failure”.

Among the features would be:

  • Low shaft diameter to length ratio (less than 60 L3 /D4) less than 2 in the metric system.
  • Large operating window.
  • C or D frame adapter to simplify driver to pump alignment
  • Centerline design for thermal expansion.
  • Oversize stuffing box.
  • Adequate bearing retention (no snap rings).
  • Positive bearing sealing. No grease or lip seals that will cut the pump shaft.
  • Reliable bearing oil level indication.
  • Bearing oil-cooling availability.
  • Low net positive suction head required (NPSHR).
  • A double volute to prevent shaft deflection.
  • Suction specific speed number below 8500 (5200 metric).
  • Dynamically balanced rotating assembly.
  • Impeller specific speed number selected for the application.
  • Duplex metal impeller.
  • The impeller should be investment cast.



  • On February 15, 2018