Abstract: A regenerative air preheater has a heat-exchange sector plate centered on an axis and formed with a multiplicity of axially throughgoing passages with intake and output heating-gas hoods axially flanking the plate and conduits for passing a heating gas from the intake hood through the plate to the output hood for heating the plate. Intake and output secondary heated-gas hoods each within one of the heating-gas hoods and axially flanking the plate are axially aligned with each other and only cover a portion of the plate. Thus the heating gas can pass through the plate only around the plate portion covered by the secondary hoods. Intake and output primary heated-gas hoods within the respective secondary hoods and axially flanking the plate are axially aligned with each other and only cover a subportion of the plate portion covered by the secondary hoods. Thus the secondary gas will be heated at regions of the plate portion not covered by the primary hoods.