CPC Subgroup
F28D 7/12 the surrounding tube being closed at one end, e.g. return type (F28D7/14 takes precedence)
Full Title
Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall > the conduits being arranged one within the other, e.g. concentrically > the surrounding tube being closed at one end, e.g. return type (F28D7/14 takes precedence)