Abstract: An internal formation for a conduit. The formation has a longitudinally extending member adapted to extend along an inside surface of at least a portion of the length of the conduit. The longitudinally extending member has an asymmetric profile in a direction transverse of the longitudinal axis of the member.

Abstract: A tubular conduit (1) is disclosed. The tubular conduit comprises a tubular portion made from a flexible material and an axially extending external helical formation (16) located around the outside of the tubular portion. The external helical formation (16) is for supporting the tubular portion. Optionally the tubular portion also comprises an axially extending internal helical protrusion (15), which imparts a helical flow to a fluid passing through the tubular portion. It is preferred that the tubular conduit (1) is a vascular graft.

Abstract: An artificial or modified natural blood flow tubing has a helical-flow inducer to induce helical flow in such a fashion as to eliminate or reduce turbulence. One inducer is a tubular stent of expansible mesh having a helical vane.

Abstract: There is disclosed an insert (2) for a conduit (4) adapted to effect helical flow in the conduit (4) comprising a longitudinally extending member having a helical formation.

Abstract: There is disclosed a method for introducing a helical formation (11) into a flexible tubular material (12). The material (12) is supported together with a surrounding helical former (13) so as to deform the material (12) to have a helical indentation (11) corresponding to the shape of the former (13). The material (12) is then set in that configuration and the former (13) is removed.

Abstract: A Method of Determining the Helix Angle of a Helical Formation for a Conduit. A method of determining the helix angle of a helical formation (4) within a conduit (1). The method includes specifying the internal dimensions of the conduit (1) and an intended fluid mass flow through the conduit (1). The helix angle is determined from the pressure drop and the turbulent kinetic energy for a conduit (1) having the specified internal dimensions and intended fluid mass flow.

Abstract: An artificial or modified natural blood flow tubing has a helical-flow inducer to induce helical flow in such fashion as to eliminate or reduce turbulence. One inducer is a tubular stent of expansible mesh having a helical vane.

Abstract: A method of assessing the effect of a conduit section (11) on flow characteristics of a first fluid in a first conduit system (1). A first fluid is caused to flow through the first conduit system (1). A transverse flow parameter of the first fluid in the first conduit system (1) downstream of the conduit section (11) is detected. At least one transverse flow characteristic of the first fluid is determined from the detected transverse flow parameter. The effect of the conduit section (11) is then assessed from the determined flow characteristics.

Abstract: There is disclosed an insert (2) for a conduit (4) adapted to effect helical flow in the conduit (4) comprising a longitudinally extending member having a helical formation.

Abstract: An internal formation (3) for a conduit (1). The formation (3) has a longitudinally extending member adapted to extend along an inside surface of at least a portion of the length of the conduit (1). The longitudinally extending member has an asymmetric profile in a direction transverse of the longitudinal axis of the member.

Abstract: A helical formation (2) for a conduit (1). The helical formation (2) comprises an elongate member defining at least a portion of a helix, the elongate member comprising two inwardly extending portions (6, 7). The inwardly extending portions (6, 7) are spaced from each other and extend along the length of the elongate member in side-by-side relationship.

Abstract: There is disclosed a method for configuring or reconfiguring branches in tubing in which the axes of at least two components of the branched structure are arranged askew.

Abstract: There is disclosed a heart valve prosthesis having a configuration such that blood flow through it has a helical flow pattern such as to substantially reduce or eliminate turbulence and dead flow regions in the blood flow.

Abstract: A helical formation for a conduit (1). The helical formation includes an elongate member (4) defining at least a portion of a helix, the elongate member (4) comprising an inwardly extending portion (6, 7). The inwardly extending portion (6, 7) extends along the length of the elongate member (4) and extends inwardly from the internal side walls of the conduit (1) for a distance equal to between 10% and 80% of the distance (r) from the longitudinal axis (3) of the conduit (1) to an internal side wall (2).

Abstract: A Method of Determining the Helix Angle of a Helical Formation for a Conduit. A method of determing the helix angle of a helical formation (4) within a conduit (1). The method includes specifying the internal dimensions of the conduit (1) and an intended fluid mass flow through the conduit (1). The helix angle is determined from the pressure drop and the turbulent kinetic energy for a conduit (1) having the specified internal dimensions and intended fluid mass flow.