the element being built-up from finned sections

Tubular elements; Assemblies of tubular elements > Tubular elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses > the means being only outside the tubular element > and extending transversely > the means being integral with the element > the element being built-up from finned sections

Tubular elements; Assemblies of tubular elements (specially adapted for movement F28F5/00) > Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses (crimped or corrugated elements F28F1/06, F28F1/08) > the means being only outside the tubular element > and extending transversely (F28F1/38 takes precedence) > the means being integral with the element (F28F1/32 takes precedence) > the element being built-up from finned sections