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 center line of the flow lumen follows a substantially helical path with a helix angle less than or equal to 65°. The amplitude of the helix is less than or equal to one half of the internal diameter of the tubing portion.

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 65°. The amplitude of the helix is less than or equal to one half of the internal diameter of the tubing portion.

Abstract: An expandable balloon for insertion in a fluid conduit of a human or animal body is movable between a collapsed condition and an expanded condition. The balloon has, when in the expanded condition, a center line which follows a substantially helical path. The balloon can be combined with a stent such that the stent is expandable by the balloon from a collapsed condition to an expanded condition.

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: The present invention relates to piping (1) for use in industrial activities, where the piping (1) has a specific geometry. In particular, the piping (1) is formed as a lowamplitude helix, which causes fluid flowing through the piping (1) to swirl. This swirl flow provides a large number of advantages. Particular applications where the piping (1) can be used include petroleum production risers and flowlines, production tubing for downhole use in wells, pipelines for the transportation of fluids, static mixers, bends, junctions or the like, penstocks and draft tubes, reactors for chemical, petrochemical, and pharmaceutical applications, heat exchangers, cold boxes, incinerators and furnaces for waste disposal, static separators, and air intakes.

Abstract: The invention relates to a petrochemical cracker having piping comprising a portion wherein the centerline of the portion follows a substantially helical path, 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.

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 centerline curves in three dimensions, to induce swirl flow in the tube. Preferably, the tube is formed as a helix.

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.

Abstract: An expandable balloon for insertion in a fluid conduit of a human or animal body is movable between a collapsed condition and an expanded condition. The balloon has, when in the expanded condition, a center line which follows a substantially helical path. The balloon can be combined with a stent such that the stent is expandable by the balloon from a collapsed condition to an expanded condition.

Abstract: The present invention relates to piping (1) for use in industrial activities, where the piping (1) has a specific geometry. In particular, the piping (1) is formed as a low amplitude helix, which causes fluid flowing through the piping (1) to swirl. This swirl flow provides a large number of advantages. Particular applications where the piping (1) can be used include petroleum production risers and flowlines, production tubing for downhole use in wells, pipelines for the transportation of fluids, static mixers, bends, junctions or the like, penstocks and draft tubes, reactors for chemical, petrochemical, and pharmaceutical applications, heat exchangers, cold boxes, incinerators and furnaces for waste disposal, static separators, and air intakes.

Abstract: The invention relates to piping comprising a portion wherein the centreline of the portion follows a substantially helical path, 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: 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.

Abstract: A method of transporting multiphase fluids during extraction of said fluids from a well. The method includes first providing a well production apparatus. The well production apparatus includes tubing for carrying a flow of well production fluids. A centre line of the tubing follows a substantially helical path, and the amplitude of the helix is less than or equal to one half of the internal diameter of the tubing. Then, the method includes transporting multiphase fluids along the tubing whilst inducing swirl flow thereof.

Abstract: The present invention relates to piping (1) for use in industrial activities, where the piping (1) has a specific geometry. In particular, the piping (1) is formed as a lowamplitude helix, which causes fluid flowing through the piping (1) to swirl. This swirl flow provides a large number of advantages. Particular applications where the piping (1) can be used include petroleum production risers and flowlines, production tubing for downhole use in wells, pipelines for the transportation of fluids, static mixers, bends, junctions or the like, penstocks and draft tubes, reactors for chemical, petrochemical, and pharmaceutical applications, heat exchangers, cold boxes, incinerators and furnaces for waste disposal, static separators, and air intakes.

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 centreline curving, preferably substantially continuously, in three dimensions.

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: A process for separating suspended material from a fluid comprising flowing the fluid through a porous matrix. The porous matrix is elastically deformable and restrained at its outlet end. The flow rate is sufficiently large so as to produce non uniform deformation of the porous matrix and thereby a gradient of porosity in the direction of fluid flow. At least a part of the suspended material is separated by retention within the porous matrix. The porous matrix/fluid system has a self cleaning capability.

Abstract: A method of determining the instantaneous arterial blood pressure of a subject which is a living being without utilizing entry of a needle or the like along an artery is capable of a high degree of accuracy and comprises the steps of applying a pressurizable device in the region of an artery and controllably pressurizing that device with fluid to an extent sufficient to eliminate arterial wall movement without collapse of the artery, the fluid pressure in the pressurizable device being monitored and providing a measure of the instantaneous arterial blood pressure of the subject. A preferred form of pressurizable device is an annular ring or cuff comprising a rigid body of annular shape over the inner surface of which is stretched a latex membrane which is pressurizable with distilled water.