Abstract: A double molded over method of manufacturing a lightning arrester in which a central core 1 is made of zinc oxide in a first step, then two metal end fittings 5, 6 are molded onto the end faces and over the side thereof, and finally a coating of elastomer material 7 is molded around the side wall of the central core and over side portions of the end fittings. The core may be formed of a plurality of smaller section bars of zinc oxide regularly disposed about a longitudinal axis with the end fittings molded onto the end faces and about the sides of the end bars whose end faces are partially metallized. In a further variant, a stack of zinc oxide based pellets having the same cross-sectional area as the core in the first example, with the stack having the same overall length as the core if stiffened by thermal compression with fusible metal inserted between pairs of pellets. The stack assembly is then compressed mechanically in conjunction with heat treatment to effect very good mechanical bonding.

Abstract: The present invention relates to a method of manufacturing a lightning arrester (100) having two end fittings (2,20) at either end of a substantially cylindrical central core constituted by a stack of pellets (6, 7, 8) made of a varistor-type material and having holes therethrough whereby the pellets are threaded over a central rod (1) made of stratified material. The stack assembly is put into compression against the two facing faces of the end fittings (2, 20) by means of the rod (1), the space between the rod (1) and the pellets (6, 7, 8) is filled by casting or injecting an insulating material, with the assembly obtained in this way being perfectly rigid, and a coating (30) of an elastomer of the EPDM type is molded over the assembly, with the coating adherring perfectly to all of the surfaces of the core and of the end fittings which it covers.

Abstract: Rigid electrical insulator including a soda-lime glass dielectric with an average thickness of 10 to 15 mm, exhibiting a substantially parabolic stress curve, wherein the maximum value of the surface compression stresses at any point in the part falls within the range of 30 to 80 MPa, while the maximum value of the internal tensile stresses at any point in the part falls within the range of 15 to 40 MPa.

Abstract: A porous material made from sintered inorganic particles. It has an open pososity of 30% to 40% by volume, a permeability to water at 20.degree. ranging from 0.6 to 60 m.sup.3 /h.m.sup.2.bar for a wall thickness of 2 cm as the average pore diameter varies from 2 to 20 microns and a crushing resistance, measured under conditions of isostatic compression, of 4.times.10.sup.8 to 5.times.10.sup.8 N/m.sup.2.

Abstract: Device consists of several gripping modules for gripping sheds on an electrical insulator, said modules being distributed along a moving beam which moves vertically to extract the insulator from the mold. The beam is supported by a moving frame designed to clear the gripper and insulator from the mold. The beam has variable dimensions enabling the number of modules to be varied according to insulator size, especially for long insulators of up to 8 meters.

Abstract: An electrical insulator (1) of the type comprising at least one dielectric (2) and an iron or steel cap (3) fixed axially on the dielectric has a device for protecting the cap against corrosion as well as electric arcs. In one embodiment (FIGS. 1-3), the protection device comprises a zinc or aluminum part (10) shaped as a dish with a center hole (11) and outlet holes (12) for the egress of rainwater. The outside wall (13) of the part (10) curves upwardly toward the cap (3) and a portion of the part (10) is disposed between the base (6) of the cap (3) and the outer surface (7) of the dielectric (2). In another embodiment (FIG. 4), the protection device comprises a solid body of revolution (30) of semi-toroidal shape which is formed of zinc or aluminum and is cast directly around the base (6) of the cap (3) and has a thin flange extending between the base (6 )of the cap (3) and the outer surface (7) of the dielectric (2).

Abstract: An improved method of manufacturing a composite structure of ceramic material reinforced by refractory fibers is disclosed, whereby the fibers are first embedded in a slip of the ceramic material containing a synthetic resin with good ceramic and fiber wetting properties and a solvent of said resin, the liquid phase is thereafter eliminated from the slip by drying, the synthetic resin is driven from the formed structure by heating, and the fiber-reinforced ceramic material is sintered. The improvement consists in avoiding the use of costly aluminum-nitride powder by initially incorporating an aluminum powder in the slip along with the resin solvent and nitriding the powder in the structure, after drying and firing, but before sintering.

Abstract: In a method of manufacturing parts or powders made of a compound of silicon or of a metal by exothermally reacting parts or powders of silicon or a metal in the solid state with a gas, wherein the differential flow rate or the pressure variation of the reactive gas in contact with the part or the powder is sensed, and the reaction is performed at increasing temperatures as a function of the said differential flow rate or pressure of the reactive gas:the improvement wherein a maximum differential flow rate or a maximum speed of pressure drop of the reactive gas is predetermined as a function of the chemical nature of the parts or powders, and optionally as a function of the density and the size of the parts, and the rise in temperature is suspended when the differential flow rate or the speed of pressure drop of the reactive gas reaches the predetermined maximum value, beyond which the reaction would run away and prevent complete transformation of the parts or the powders being obtained.

Abstract: A titanium or titanium alloy pin for cement-free fixing in a long bone for a joint prosthesis or for bone repair is surrounded by a lattice of titanium wire with a mesh size of at least 0.3 mm. The central part of the pin and the lattice are coated with a coating of titanium oxide which protects them against long-term corrosion. The lattice is further coated with a biodegradable and biocompatible material having a low modulus of elasticity.

Abstract: The ends of a fiber-reinforced resin rod are inserted through sealing grommets into cavities of respective end fittings; the end fittings of the assembly are placed in accurately spaced end moulds; the rod is encased in intermediate half shells; an insulator covering is moulded around the rod by filling the half shells; and the end fittings are then fixed to the rod by embedding or swaging.

Abstract: A tempered glass dielectric material for use as an electrical insulator is thermally tempered to produce surface compression between 200 MPa and 400 MPa. At least part of the material is then chemically tempered under conditions of temperature and duration such that the surface compression due to the thermal tempering is reduced by between 50% and 80%. The chemical tempering is effected by applying to the relevant part of the material, at ambient temperature, a solution containing alkaline salts. This solution is dried and the material then heated for several hours at a temperature between 300.degree. C. and 500.degree. C. The solution has the following composition (in percentage by weight):______________________________________ H.sub.2 O 70% to 90% Starch 2% to 10% KNO.sub.3 4% to 12% K.sub.2 HPO.sub.4 + KCl + K.sub.2 SO.sub.

Abstract: An electrical insulator component comprises a one-piece block of moulded fins (11, 12, 13) disposed around an insulating core (10). The surface of the block of fins includes a moulding line (21, 22, 23) and said moulding line has arcuately displaced segments in that the portion 22 extends circumferentially while the portions 21 and 23 extend longitudinally but in different planes. The net result is that dirt building up along the join line does not form a continuous straight-line low resistance path for leakage currents.

Abstract: The member is in the form of a hollow body having a skirt (2) surmounted by a head (1), the entire body exhibiting circular symmetry about an axis (10). The hollow body has an internal ring (5) at an intermediate level between the head and the skirt. The surface of the internal ring is corrugated as traced by a generator line at a constant angle to said axis and moving around a closed corrugated curve situated in a plane orthogonal to said axis. This arrangement provides resistance to torsion forces without requiring any sharp inside edges that are difficult to manufacture in tempered glass.

Abstract: The invention relates to a static cylindrical monolithic cellular structure with a large contact area, said structure being used in particular for a static heat exchanger and including a plurality of parallel ducts. Its general organization is essentially cylindrical, and the ducts are defined by radial walls (10) and circumferential walls (11). Said ducts form groups for conveying different fluids with the groups being in an essentially radial configuration, i.e, with groups for conveying different fluids at least some of the radial type walls constituting the boundaries between different fluid flows. Application in particular to static exchangers and to filters.

Abstract: The invention relates to line insulators made of organic material. Such an insulator comprises a bar (7) of high tensile strength, a protective sheath (8) made of an elastomer material, a plurality of fins (4) and an anchor fitting (2) at each end. In accordance with the invention, at least one inner part of the insulator is semiconductive along the whole length which separates the anchor fittings (2); this part may be constituted either by the sheath (8) itself or by the bar (7) and the bedding material in said fittings. Application, in particular, to line insulators intended for use in highly polluted zones.

Abstract: The invention relates to the manufacture of a body of a cellular structure by extruding a ceramic material through a die. The die comprises a succession of coaxial components (6, 10) fitted one round another, with two adjacent components defining between them longitudinal ducts (2) whose downstream ends communicate with an annular duct (3) and wherein the bottoms of said coaxial components fitted one round another have essentially radial notches (4) level with the annular ducts, the width of said notches being less than that of the longitudinal ducts, so that the ceramic material which flows through said longitudinal ducts is evenly distributed in the annular ducts and in the radial notches to form a body with a cellular structure directly on extrusion.The invention has application to thin-walled honeycomb ceramic structures.

Abstract: The invention relates to fixing a metal strength member on a non-metal part. A heat-resistant fibre glass layer is inserted between the strength member and the non-metal part, the layer extending throughout at least the zone of the non-metal part which corresponds to the point where the molten metal which forms the strength member is injected and being coated with a non-adhering inert inorganic substance so that the layer is thus compressed between the non-metal and the metal part when the metal part is applied against the non-metal part. Application in particular to manufacturing tempered glass electric insulators with moulded aluminium caps.

Abstract: A ceramic unit for indirect heat exchange, said unit being formed by extruding raw ceramic material in a parallel duct configuration, piercing a first series of inlet and outlet orifices for a fluid at the ends of a first series of ducts, the axes of said orifices being perpendicular to those of the ducts, and firing the unit. The inlet orifices (5) and/or the outlet orifices (9) are formed by making oblique cuts (7,10) on the ends of the rows of ducts to provide inlet or outlet openings perpendicular to the common direction of the ducts and then closing off the ends of the obliquely cut rows. Application to heat exchangers for turbine engines.

Abstract: The invention relates to line insulators made of organic material. Such an insulator comprises a bar (7) of high tensile strength, a protective sheath (8) made of an elastomer material, a plurality of fins (4) and an anchor fitting (2) at each end. In accordance with the invention, at least one inner part of the insulator is semiconductive along the whole length which separates the anchor fittings (2); this part may be constituted either by the sheath (8) itself or by the bar (7) and the bedding material in said fittings. Application, in particular, to line insulators intended for use in highly polluted zones.

Abstract: A titanium or titanium alloy pin for cement-free fixing in a long bone for a joint prosthesis or for bone repair, said pin being surrounded by a lattice of titanium wire with a mesh size of at least 0.3 mm. The pin has a rectangular cross-section and two of its surfaces have respective longitudinal grooves (3) which are notched transversely to form shoulders (5) perpendicular to the pin axis, said shoulders giving the pin a scaly profile. Application to a total prosthesis of the hip.