Semi welded PHEs are an optimum solution in applications where gaskets are not compatible with one of the media. Our semi-welded PHEs are assembled with laser welded modules. These are very useful for applications such as:

Ammonia condensers.

Semi-welded PHEs overcome this limitation! These are as flexible as gasketed heat exchangers while enhancing the application range for PHEs for use with aggressive fluids 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 volume results in significant 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 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.