Flowserve's Mark 3 power ends are designed to be the last bearing frame you'll ever need. With advanced engineering for key components such as shaft bearing and mechanical seals, these premiere power ends are built to withstand severe duty and harsh environments AND simplify maintenance - all combining to create your longest MTBF, longest equipment and component life and lowest maintenance costs.

Standard Mark 3A Power End

  • Offered standard on all Durco Mark 3 ANSI pumps.
  • Double row angular contact outboard and single row, deep groove inboard bearings provide excellent axial + radial load support.
  • External micrometer enables accurate impeller clearance setting in 20 seconds, restoring pump efficiency.
  • Critical shaft surfaces ground to 0.4 micron (16 μin) finish to ensure secondary sealing ability of the mechanical seals.
  • ANSI B73.1 ductile iron frame adapter provides strength and facilitates interchangeability.
  • Metal-to-metal construction assures a true running and concentric shaft, extending bearing and mechanical seal life.
  • Double lip oil seals.
  • Top mounted vent and oil filler.
  • Trico WATCHDOG® constant level oiler with integral viewpoint.
  • … plus options to maximize your application.

Mark 3A ANSI Power End

Durco Mark 3 ANSI pumps can be upgraded to the ANSI 3A at initial purchase or exchanged later on. Featuring all the reliability and performance-enhancing properties as the standard Mark 3A, the ANSI 3A additionally offers:

  • Certified clean room assembly.
  • Inpro Seal's VBXX non-contact Vapor Block Bearing Isolators that keep lubricants in and contaminants out.
  • The largest shaft and bearing components available in standard ANSI pumps.
  • The lowest shaft deflection index (L3/D4) of any ANSI process pump.
  • Top vent replaced with a magnetic drain plug.
  • Lubrication options, including oil mist systems and shielded/grease-lubricated bearings.
  • A choice of shaft materials and configurations.
  • Materials + workmanship guaranteed for life when installation, operation and maintenance procedures best practices are followed.

Prima3 Power End

Prima3 Power Ends can be installed on most leading competitor ANSI pumps, with just a shaft and adapter change. But this simple retrofit enhances operation and longevity, while reducing downtime and costs through:

  • All the exceptional Mark 3A Standard and ANSI 3A advanced features listed here, and more!
  • Certified clean room assembly ensures optimal tolerances on all fits and finishes.
  • Lifetime warranty on materials and workmanship, extending competitive ANSI pump brand performance and ROI.

Power End Services

PP&S offers several Quick Ship and Exchange programs, along with expert upgrade and retrofit services to the latest available technology and "as new" OEM specs.


For in-depth information on all three Flowserve power end configurations and services, explore the video and literature library on this page. And be sure to contact your local PP&S team for 1:1 applications and engineering guidance on the Durco Mark 3A Standard, ANSI and Prima3 power ends.

Our Engineering Services team can also support your process with proactive Reliability and TLC Solutions that enhance performance and longevity while reducing costs.

Watch these videos to learn more about Mark 3 Power End operation and easy maintenance

Mark 3 Power End literature

Specification Tools

Ongoing Support

Take the next step in solving for tomorrow's challenges today. Give us a call at 800.275.4786

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Charlotte, NC 28217
704.588.6250 • Fax 704.588.6258

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PP&S provides Rotating/Process Equipment and Total Lowest Cost solutions in Alabama, Georgia, North Carolina, South Carolina, Virginia and the Florida panhandle. If you are seeking equipment or support outside these areas or in the EU, please refer to the OEMs' website for distributors in your area.