16 Elements of Sanitary Heat Exchanger Design

General news · 2021-05-29

What is needed for a heat exchanger to meet the challenges of ultra-high purity applications?

A lot, actually. Engineers have continually fine-tuned heat exchangers over the past several decades to better serve the bioprocessing industry as specified by BPE codes, CGMP regulations, and other standards. Here are 16 basic elements of sanitary heat exchanger design and manufacture:

  1. Shell-and-tube design – Eliminates drainage impediments found in plate-and-frame designs.
  2. Double tubesheets – Greatly decreases the possibility of cross-contamination between shell and tube media.
  3. HydroSwage® sealing of tubes into tubesheets – Prevents excessive tube-wall thinning and spiral stress created by mechanical tube rolling.
  4. Tube-end seal welds – Prevent accumulation of foreign materials in crevices between the tubes and tubesheet.
  5. 2° overall slope toward outlet; no low points or impediments – Provides enhanced drainability.
  6. Fully radiused pass pockets – Allow pass-pocket drainability despite the two-degree slope of the heat exchanger.
  7. Drain channels between pass pockets – Allow upper pass-pockets to drain to the heat-exchanger drain point.
  8. Leak detection slots – FDA-required visual indicator of a breach in a tube-to-tubesheet seal.
  9. 316L stainless steel or higher alloy (AL6XN, Hastelloy®, etc.) – Provides corrosion resistance.
  10. <20 micro-inch Ra product-contact-surface finish – Reduces potential for biofilm buildup.
  11. Electro-polishing – Provides a deeper passive (corrosion-resistant) layer than simple passivation.
  12. Welds polished flush and blended – Reduces areas of potential contaminant buildup.
  13. Seamless tubing – Eliminates potential for inclusions in welded-tube welds.
  14. Special tube-bending dies – Prevent surface disruption of U-tube interiors.
  15. Material not sourced from China, India, Eastern Europe, etc. – Ensures quality steel.
  16. No processing of carbon steel in the same shop as stainless steel – Prevents risk of embedding carbon steel into stainless steel during manufacturing operations, which can create a nucleus for corrosion.