Semi-Welded Plate Heat Exchangers

Certified Company ISO 9001-2008

Semi-Welded Plate Heat Exchangers


In the past, no satisfying solution was available for using gasketed plate heat exchangers for special process conditions or aggressive media. The limitation was always the gasket material.

Semi-welded units overcome this limitation! These are as flexible as gasketed heat exchangers while enhancing the application range for PHEs for use with aggressive liquids and gases, such as ammonia or aggressive process chemicals where suitable elastomers are not available to act as a sealant between the plates. In the case of ammonia refrigeration, the reduced hold-up volume results in significant additional savings.

This type of heat exchanger uses a unique approach: alternating channels are laser welded. Aggressive media (for example Ammonia) flows in the welded channels. Non-aggressive media (like brine or water) passes through the gasketed channels. Despite partial welded construction, the unit can easily be disassembled to replace gaskets or to take care of other maintenance.

Like all VARALKA products, they are also highly efficient, reliable, and easy to operate and maintain.


Applications of Semi-Welded PHEs

  • Ammonia Evaporators – Gravitation, DX or Flooded
  • Ammonia Condensers
  • Cascade Heat Exchangers (NH3, CO2)
  • Ammonia De-superheaters, Economisers
  • Oil Coolers
  • Sulphuric Acid Coolers

Product Program

Connections SizesDN25 to DN250
Working Pressure< 63 Bar
Working Temperature180 deg C
Plate MaterialsSS304 / SS316L, Titanium Gr 1 / 11, Hastelloy C-276
Gasket MaterialsCR, EPDM, NBR, HNBR FKM, PTFE Encapsulated
Frame MaterialsIS2062, SA516 Gr 60/70, SS304, SS304 Cladded
Tie-Rods, FastenersIS1367, SA193/SA194, ASTM A193/194
Construction CodesStandard Engineering Practice, ASME Sec VIII Div 1, PED, U Stamp(*)
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