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Centrifugal Pump Throttle Bushings

Throttle bushings and center-stage bushings are upgraded to composite materials for similar reasons as the pump wear rings.

Benefits of using composite materials with pump throttle bushings:


  • Eliminating the metal-to-metal contact points nearly eliminates the risk of pump seizure
  • The throttle and center bushing will not seize or gall during slow roll or alignment
  • The pump will have a better tolerance of run-dry events and other process upsets, with a chance of surviving extended off-design conditions
  • Higher efficiency due to lower leakage losses across the throttle bushings
Throttle Bushing
Machining Vespel CR-6100

What to do when applying composite materials to pump throttle bushings:

  • Use the existing metal center-bushing housing as a holder for a composite material insert.
  • Depending on the part geometry and operating temperature, the pump throttle bushing can be made from either solid composite material, or the existing metal part can be used as a holder for a Vespel® CR-6100 or B-Series material insert.
  • If you have upgraded the wear rings to Vespel® CR-6100, reduce the clearance of the throttle and center bushing to be 0.002” (0.05 mm) less than the wear ring clearance. Otherwise, keep the original design clearance.
  • Make sure the pump overhaul results in good rotor concentricity. (The rotor should turn freely after assembly. Slight rubbing at the wear rings from shaft sag is normal, but any hard rubs should be corrected before putting the pump into service.)
  • Use PERF-Seal™ design for high differential pressures and temperatures.

Contact Boulden Today for Pump Throttle Bushings

Request a quote today with your application details to upgrade your throttle bushings in centrifugal pumps to a composite material. We have the material you need in stock and can ship immediately. Or contact us if you want to know more about the composite materials Boulden offers. Looking for additional info? Sign up for our newsletter

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