Abstract: A stent for supporting part of a blood vessel which stent includes a supporting portion around which or within which part of an intact blood vessel other than a graft can be placed so that the stent internally or externally supports that part and the supporting portion of the stent is of a shape and/or orientation whereby flow within the vessel is caused to follow a non-planar curve. By maintaining non-planar curvature in the vessel itself, favourable blood flow velocity patterns can be achieved through generation therein of “swirl” flow. Failures in such vessels through diseases such as thrombosis, atherosclerosis, intimal hyperplasia or through blockage, kinking or collapse, can be significantly reduced.

Abstract: The invention relates to piping for use as a pyrolysis tube in a cracking furnace. The tube is formed such that it has at least one section whose centreline curves in three dimensions, to induce swirl flow in the tube. Preferably, the tube is formed as a helix, more preferably a low-amplitude helix. The invention also extends to various other uses of piping with low-amplitude helical geometry.

Abstract: Tubing or piping for carrying a multiphase flow is provided with means for inducing swirl flow, such that the denser components of the flow tend to the outer wall of the tubing or piping, and less dense components tend to the center of the tubing or piping. The flow thus exhibits a “centrifuge” effect, which prevents lighter or heavier components of the flow from accumulating in upper or lower regions respectively of the tubing or piping, and reduces the risk of airlocks and the like. Preferably, the tubing or piping is in the form of a helix, which may be a low amplitude helix.

Abstract: A device for placement externally of a body fluid flow conduit, includes a tubing portion defining a longitudinally extending cavity for receiving the conduit. The longitudinal cavity of the tubing portion is substantially free of ribs or grooves. The center line of the longitudinal cavity follows a substantially helical path with a helix angle which is less than or equal to 65°. An amplitude of the helix is less than or equal to one half of the internal diameter of the tubing portion.

Abstract: The invention relates to piping including a portion wherein the centerline of the portion follows a substantially helical path, and wherein the amplitude of the helix is less than or equal to one half of the internal diameter of the piping. When fluid flows in such piping, it is made to swirl. This provides a number of advantages, such as improved in-plane mixing of the fluid, enhanced uniformity of residence time, and so on. The invention also extends to various methods of making such piping.

Abstract: A graft includes a flow tubing having a tubing portion defining a flow lumen. The flow lumen of the tubing portion is substantially free of ribs or grooves. A centre line of the flow lumen follows a substantially helical path with a helix angle less than or equal to 650°. The amplitude of the helix is less than or equal to one half of the internal diameter of the tubing portion.

Abstract: A stent for insertion in a fluid conduit of a human or animal body when the stent is in a collapsed condition and for expansion to an expanded condition, includes an outer wall for engagement with the conduit. The outer wall has a helical portion which in the expanded condition extends longitudinally and circumferentially, and which, upon expansion of the stent from the collapsed condition to the expanded condition, resists extension.

Abstract: A pipe network having an area where one planar bifurcation is followed by a second planar bifurcation. The planes of the two bifurcations are not coincident. This reduces non-uniformity in wall shear rates at the exit pipes of the second bifurcation. Preferably, the plane of the second bifurcation is rotated relative to the plane of the first bifurcation. In an alternative form, the pipe network has a planar curve followed by a planar bifurcation, with the planes of the curve and the bifurcation not being coincident.

Abstract: A turbine for use in electricity generation is provided with pipework for gas or vapor entering or leaving the turbine. The pipework includes a rigid section the centerline of which curves in three dimensions.

Abstract: Production and processing plant in particular for the processing of food or hydrocarbons and the production of pharmaceuticals, including pipework for transferring fluids from one part of the plant to another, the pipework including at least one substantially rigid pipe having at least one section with a centerline curving, preferably substantially continuously, in three dimensions.

Abstract: A vascular prosthesis includes a length of generally hollow tubing having openings at both ends thereof. The prosthesis includes at least one curved portion whose curvature extends within three dimensions of two mutually perpendicular planes such as to induce swirl flow in a liquid medium when such medium flows through the curved portion.

Abstract: A surgical cannula includes a generally hollow inlet portion which can receive a fluid flow and an angled outlet portion connected in fluid communication with the inlet portion. The outlet portion is disposed at an angle of less than 180 degrees with respect to the longitudinal axis of the inlet portion. The inlet portion is provided with a structure to impart a rotational component of flow to fluid before such fluid encounters the angled outlet portion.