(833) 609-0173

API Plan 03

Open-ended or tapered seal chamber.

API Plan 03


Seal flush Plan 03 is used in applications where collection of solids within the seal chamber is anticipated. Commonly referred to as a “taper bored” seal chamber, the seal chamber shape creates a velocity profile that expels solids and circulates cool fluid to the seal.

Application Notes

  • Circulation between the pump and seal chamber is driven by the geometry or flow enhancement features in the seal chamber.
  • Used in applications where solids would collect in a traditional cylindrical seal chamber.
  • Flush port is plugged.
  • Provides cooling for the seal without use of any external hardware or piping.
  • Vents air or vapors from the seal chamber in horizontal pumps.
  • No throat bushing.
  • Control of the seal chamber environment is limited.
  • The seal chamber is not self-venting in vertical applications.
  • May not be recommended in applications with high seal chamber pressures and/or temperatures.


  • Maintenance of cool seal environment without the need for external piping
  • Works well with horizontal pumps
  • Zero throat bushing


  • Limited control over the seal chamber environment
  • Might be unsuitable for high pressure applications

Request a Quote