Heat exchangers

摘要

A heat exchanger which includes a casing having an outer tube and an inner tube fixed therein. Holes are formed in the inner tubes and face a heat transfer surface of the outer tube. Hot exhaust gas may be passed from an inlet of the outer tube into the inner tube, through the holes in the inner tube to an outlet. Coolant water may be passed through the casing from an inlet port to an outlet port. Baffles and/or twist coils may be provided to improve heat transfer.