API 682 Plan 53B/C

The MP53 series aligns with API 682 Plans 53B and 53C by supplying a liquid barrier fluid to a dual seal assembly at a higher pressure than the seal chamber.

Our barrier seal reservoirs are built to ASME Section VIII standards and ASME U code stamps are available. All our barrier fluid systems, whether custom or standard designs are designed and built to the current API 682 requirements.

Barrier Fluid Reservoir – API 682 Plan 53



Our MP53B unit supplies an external barrier fluid pressurized by a bladder accumulator. This sends clean barrier fluid to the dual seal at a pressure greater than the seal chamber.

  • U stamp accumulator standard
  • 5-10 gallon capacity
  • Air- or water-cooled availability
  • Integral barrier fluid make-up pump


The external barrier fluid is pressurized by a piston accumulator and supplies clean barrier fluid to the dual seal at a pressure greater than the seal chamber.

  • Integral head porting eliminates pigtail design
  • U stamp coded vessel design
  • Magnetic level indication available

How it Works

How Does a Pressurized Barrier Fluid Reservoir Work?

A pressurized external barrier fluid reservoir forces the circulation of clean fluid to a pressurized dual mechanical seal, lubricating the inner and outer seal faces. The reservoir can be equipped with level, pressure, and temperature instrumentation to provide real-time process feedback on mechanical seal health.


For more information on our MP50 seal reservoir systems

Quote Request

Depending on your specific needs and application, Flexaseal can help you identify the ideal products. Contact us to tell us about your needs and request a quote.