Types of Welded Plate Heat Exchangers
There are two main configurations:
1. Fully Welded Plate Heat Exchanger
This is the most common type referred to as “welded PHE.” The entire plate pack is welded together into a single, rigid block. There are no gaskets whatsoever.
- Construction: All plates are welded at their edges. The outer casing is often formed by the welded plates themselves, eliminating the need for a separate frame.
Implication: It is a permanent, non-serviceable unit. It cannot be opened for cleaning or inspection
. Semi-Welded (or Twin-Plates) Plate Heat Exchanger
This is a hybrid design that offers a compromise between the robustness of welding and the serviceability of gaskets.
- Construction: Plates are welded together in pairs to form “cassettes.” These welded cassettes are then stacked together, but the connections between the cassettes are sealed with gaskets.
- Implication: This creates two separate fluid circuits:
- One fluid flows through the welded channels (completely contained within the cassettes).
- The other fluid flows through the gasketed channels.
- The unit can be opened to access and clean the gasketed side, but the welded side remains permanently sealed.