Patent ID: 8454675

Claim:
An internal formation for a conduit, the formation comprising a longitudinally extending member adapted to extend along an inside surface of at least a portion of the length of the conduit and projecting radially inwardly into the interior of the conduit, the longitudinally extending member having an asymmetric profile in a direction transverse of the longitudinal axis of the member, wherein a first surface of the longitudinally extending member is at least partially directed towards an inlet of the conduit and a second surface of the longitudinally extending member is at least partially directed towards an outlet of the conduit and wherein, at each radial cross-section of the conduit along which the longitudinally extending member extends, the angle that the first surface subtends with a diameter of the conduit extending through a portion of the profile of the longitudinally extending member closest to the radial centre of the conduit is less than 20°, and wherein the internal formation effects spiral flow of a fluid flowing through the conduit wherein, at each radial cross-section of the conduit along which the longitudinally extending member extends, the first surface subtends with the diameter of the conduit extending through the portion of the profile of the longitudinally extending member closest to the radial centre of the conduit at a smaller angle than the second surface subtends with the diameter of the conduit.