Abstract: A flux-cored wire for welding shielded by a flow of gas, in particular of the rutile or slag-free type, composed of an outer metal sheath and a central core comprising filling elements, and an MAG gas-shielded welding process using such a flux-cored wire for producing a welded joint on a steel construction, such as an offshore platform or a storage tank. The welded joint obtained has improved impact strength and improved toughness, and contains less than 65 ppm nitrogen, from 300 ppm to 0.12% carbon, from 0.01% to 0.6% silicon, from 0.9% to 1.9% manganese, from 20 ppm to 0.08% titanium, from 1 ppm to 80 ppm boron, from 5 ppm to 150 ppm aluminum, from 10 ppm to 0.02% niobium and from 10 ppm to 0.02% vanadium.

Abstract: A process and a device for the gas-shielded MIG welding in modulated-spray mode, of aluminum, particularly aluminum alloys, or stainless steels, in which the current is modulated at a modulation frequency of less than 60 Hz. The shielding gas contains at least 90% helium, argon or a mixture thereof and at most 1.95% of at least one minor gaseous component chosen from oxygen and carbon dioxide. This process allows effective degassing of most of the diffusible hydrogen liable to be found in the pool of molten metal and improves the appearance and quality of the weld beads thus produced on workpieces or equipment intended for the rail, sea, air, road or space transport industry or for the chemical, petrochemical, electronic, nuclear or agrochemical industries.

Abstract: Plasma torch (1) equipped with a torch head (1') including a nozzle holder (10) and a nozzle (4), the nozzle (4) being fixed to the nozzle holder (10) by the use of fixing elements (14). Safety electrical switch unit (3) controls the electric current supplied to the torch head (1'). A removable protective shroud (5) surrounds the torch head (1') and comprises, on the one hand, at least one actuating element (6) capable of interacting with the safety electrical switch unit (3) in order to make it possible to supply electric current to the torch head (1') and, on the other hand, retaining elements comprising a spring clip (8) capable of interacting with a circular groove of the nozzle (4) to allow the protective shroud (5) to be integrated with the nozzle (4). Such a plasma torch is useful for welding or cutting a piece of metal.

Abstract: A device and a method of manufacturing a metal tube made from a metal sheet with two substantially straight and parallel longitudinal edges, in which method the two longitudinal edges of the metal sheet are welded together using a welding method employing at least one electric arc between at least one electrode (Ei) and the metal sheet in contact with at least one ground lead (PMi), in which the plane of each ground lead (PMi) is positioned a distance (e.sub.i) of between -5 mm and +25 mm with respect to the plane of each corresponding electrode (Ei), the positive direction being the direction of relative travel of the metal sheet with respect to the at least one electrode (Ei).

Abstract: The invention relates to a plasma arc welding process and a plasma arc welding device for aluminum and its alloys, which process comprises at least one step of initiation of a pilot arc by means of an auxiliary current which is delivered by an auxiliary current source and flows in a pilot-arc circuit, one step of feeding with plasma gas, one step of initiation of a main arc by means of a main current which is delivered by a main current source and flows in a main circuit, one step of cyclic variation of the polarity of the main current so as to obtain at least one phase of descaling the material to be welded with a first current polarity and at least one phase of welding the material with a second current polarity, and in which process the supply of auxiliary current to the pilot-arc circuit is stopped during the descaling phase and the main circuit and to the pilot-arc circuit are supplied with main current.

Abstract: A plasma torch provided with an electrode (1) having an approximately cylindrical or frustocylindrical elongate shape, the electrode (1) including at least one recess (9) made in at least part of its external peripheral wall (15). In order to deflect and guide the gas flux entering the plasma torch, the recess (9) in the electrode (1) lies opposite the orifice or orifices (7) for introducing or injecting the gas flux into the torch.

Abstract: An improved set of stents for autologous tissue heart valves is provided. The stents are designed with the aid of a computer-aided-design (CAD) system, and nest within each other to securely clamp a piece of tissue which forms the leaflets of the heart valve. The geometrical features of the stents are designed to provide uniform nesting between the stents to prevent the formation of stress raisers on the tissue. Additionally, the windows in the stent posts are narrowed to prevent the suturing needle used during implantation of the valve from becoming lodged in the garter springs which clamp the outer stent to the inner stent. Finally, the sock covering the outer stent is bonded to the stent base at both upper and lower locations to isolate the bonds from the patient's blood flow.

Abstract: The plasma torch head comprises an axial electrode (10) with a flat end surface (16) associated with a cup-shaped peripheral nozzle (12). The bottom (20) of the nozzle (12) comprises an axial conduit (22) for ejection of the plasma jet, and its lateral wall (24) surrounds the electrode (10) and delimits with this latter a substantially annular supply space (26). The torch head comprises structure (38) for the flow of a plasmagenic gas in the annular supply space (26) in a substantially axial direction. The end surface (16) of the electrode (10) delimits with the bottom (20) of the nozzle (12) an annular space (29) for lamination of the flow of the plasmagenic gas. For use in plasma cutting torches.

Abstract: A method of assembling a heart valve is provided for use with an inner and a spreadable outer stent. The outer stent is mounted onto a spreading tool including a spreading ring, and expander, and a plunger. A protective cap is placed over the outer stent and plunger to prevent relative rotation of the outer stent to the expander prior to the complete spreading of the outer stent. The inner stent, with tissue wrapped thereon, is mounted onto an insertion tool including a mandrel having a plurality of guide rails for mating with slots of the spreading ring, wherein the guide rails in the slots provide axial and radial alignment of the inner and outer stents. The mandrel holding the inner stent is inserted through the spreading ring holding the outer stent, thereby releasing the mated stents from the spreading ring and mandrel and securely clamping the tissue between the stents.

Abstract: A method of manufacturing and testing a tissue heart valve during open heart surgery is disclosed. A piece of autologous tissue from the body of the patient is precisely cut according to the size of the open annulus remaining after excision of the patient's heart valve, with a plurality of holes being formed in the tissue. The tissue is situated between appropriately selected first and second stents so that the holes are registered with corresponding tissue alignment members in one of the stents, and the stents are positioned together to securely clamp the tissue therebetween. The constructed tissue heart valve is then mounted in a test chamber and visually inspected for leakage.

Abstract: This invention relates generally to a rapid assembly, concentric and flexible mating stent, tissue heart valve which can be assembled from prefabricated, sterile kits by a non-surgeon in the limited time available in an operating room. The kits provide the necessary tools and apparatus for harvesting the tissue and measuring the open annulus within the patient's heart. In addition, the kits contain size-specific components to be used during the rapid manufacture of the tissue heart valve.

Abstract: A method for constructing stents for autologous tissue heart valves is provided. The method includes creating a stent profile primitive which is rotated about a first axis to create a solid stent blank having inner and outer surfaces. First and second splines are created and intersected with the inner and outer surfaces, respectively, to form a plurality of planes. Posts are formed on the stent blank by removal of material above the planes, and filleting is performed to provide a smooth upper surface for each post. Additional features corresponding to whether the stent is an inner or an outer stent for the heart valve are added, and the final stent shape is input into machine tooling which cuts an electrode into the corresponding stent shape. The electrode is then used to dissolve a pattern into a block of metal, such as a nickel-steel alloy, to form the final mold of the stent.

Abstract: The present invention provides a novel tissue cutting device for autologous tissue heart valves which accurately cuts the tissue to a predetermined configuration in a minimal amount of time. The disposable tissue cutting die of the present invention is comprised of a cover, a base member, a continuous blade enclosing a desired spatial configuration and an actuator for forcing said tissue against the entire perimeter of the blade.

Abstract: A concentric mating stent tissue heart valve which is capable of being assembled with a variety of tissue sources is provided. A tester for rapidly testing a tissue heart valve is provided comprising a substantially transparent viewing chamber having a plurality of size-specific mounts for mounting the valve within the chamber. The tester further comprises an element for displacing a volume of solution through the valve to test the opening and closing of the valve and to determine the amount of leakage through the valve when the valve is in a closed position.

Abstract: A method for assembling a concentric mating stent tissue heart valve which is capable of being assembled with a variety of tissue sources is provided. A plurality of prefabricated kits are also provided which enable the valve to be assembled with autogenous tissue in the limited time, i.e., 10 minutes or less, available in the operating room. A series of obturators may be used to size an annulus of the heart to be fitted. A precisely-configured cutting die is used to produce a precisely-cut tissue with a plurality of heart valve leaflets when the tissue is positioned between the first and second stents.

Abstract: A tissue heart valve test device which is capable of testing the valves in a rapid manner before implantation to ensure that there are no unacceptable leaks or flaws. The test device enables the valve to be tested in the operating room during the open heart procedure. The test device is configured with a chamber which allows the user to thoroughly visually inspect the valve as part of the test criteria. In addition, the test device is provided with size-specific mounts which are adapted to the particular valve to be tested.

Abstract: The present invention provides a prosthetic heart valve holder specifically configured to hold a prosthetic heart valve comprised of a stent. The heart valve holder assembly has three main components: a handle, a valve capture loop assembly and a valve retainer. The prosthetic heart valve is secured to the valve retainer by a loop of suture as the surgeon sutures or attaches the valve to the annulus of the heart. Thus, the valve holder assembly facilitates attachment of the prosthetic valve to the annulus so that the procedure may be performed in a time and labor efficient manner.

Abstract: An assembly tool for a bioprosthetic heart valve is disclosed. The tool assembles a valve having an inner and a spreadable outer stent, and includes a spreading ring with an elevated lip to hold the spread outer stent, an expander having fingers which contact the outer stent base to spread it apart, and a plunger to spread the fingers of the outer stent. An assembly mandrel having indexing rails allows the insertion of the inner stent into the spread outer stent while maintaining the correct rotational positioning of both stents. A shedding cap protects the tissue wrapped on the inner stent from abrasion during insertion.

Abstract: A stentless heart valve assembled from autologous tissue is provided. The tissue is cut into a rectangular shape, folded, and stapled at several locations to form the cusps of the valve. The outer walls of the valve are pinched at the midpoint of each cusp to prevent the cusps from adhering to the valve walls. The ends of the rectangle are then stapled to form the annular valve itself.

Abstract: A concentric mating stent tissue heart valve which is capable of being assembled with a variety of tissue sources is provided. The valve comprises at least one piece of tissue clamped between an inner and an outer stent. The outer stent is configured with a plurality of spaced posts extending from a base, wherein the posts are configured with open windows so that at least a portion of the tissue in the assembled valve is exposed through the windows. Several embodiments of the outer stent are disclosed, including where the outer stent comprises a crimped metal wire frame covered with a Dacron tube.