[Hairpin / Multitube Heat Exchangers]

The Principle

Hairpin exchangers are jacketed ‘U’ tube heat exchangers operating in a true countercurrent flow (hot fluid outlet temperature is below the cold fluid outlet temperature) resulting in a very energy efficient design.

Another important feature of hairpin exchanger is the type of enclosure which allows for the removal of the tube bundle and accommodates for thermal expansion without requiring expansion or packed joints.

The Configurations

Hairpin exchangers are available in two configurations: a single tube (Double-pipe) or multiple tubes (Multi-tube) within the shell.

  • Double-pipe heat exchangers utilize a single pipe-within-a-pipe design and are commonly used for high fouling services such as slurries where abrasive materials are present and also for smaller duties. Standard shell diameters range from 2” to 6”.
  • Multi-tube heat exchangers are used for larger duties with standard shell design diameters up to 30”.

Finned tubes, U-tubes, straight tubes (with rod-thru capability), fixed tube sheets and removable bundles are options as well.

Advantages

  • Process Advantages: Hairpin units are preferable and can be more economical than TEMA-type when applications for extreme temperature crossing, high pressure, low pressure drop or high temperatures are required.
  • Operation and Maintenance Advantages: Since the bundle is easily removed, mechanical cleaning is simple.
  • Flexibility: Double Pipe Hairpin exchangers can accommodate changes in stream flow rates or other conditions. Unlimited numbers of sections can be re-arranged in parallel and in series to fit new process conditions.