Double-wall units prevent intermixing of fluids due to a plate failure. Two plates are pressed together to ensure a tight fit to minimize heat transfer losses while maintaining a leak path in case of plate failure.

Plate and Frame heat exchangers use a combination of chevron-style heat transfer plates sequenced between a frame plate and pressure plate. The heat transfer plates have holes at the four corners forming a header that distribute the respective flows to the opposite sides of each plate when the plates align. The fluids are confined to the heat transfer surface of the plate or the port as appropriate with elastomer gaskets.