Abstract: The present invention relates to a process for the acquisition and processing of screen images or radiographs and to an apparatus making it possible to inspect or control mechanical parts. The process consists of obtaining at least two screen images of the part to be inspected, converting said images into digital video images coded on several grey levels, correcting each image with respect to itself and then with respect to a reference image and finally binarizing the corrected images in order to superimpose them, so as to determine the image points which correspond and thus detect defects. Application to the control and inspection of mechanical parts.

Abstract: A hollow blade for a turbomachine comprises a unitary body having a multiplicity of transverse cavities in at least the airfoil shaped portion of the blade, and plugs disposed within the cavities and restoring the surface continuity of the intrados and extrados faces of the aerofoil shaped portion, the plugs being rigidly secured to the unitary body, such as by welding.

Abstract: The process and apparatus of the invention permits the production of annular parts, such as ferrules, on which machining operations are to be carried out. The process includes the steps of bending a predimensioned metal sheet by a series of internal supports mounted on a rotary plate and by a pressure roller bearing on the outer surface of the sheet. One complete rotation of the rotary plate makes it possible to completely bend the sheet into the form of a ferrule. The second main operation includes carrying out of a welding operation on the two ends of the metal sheet. This process makes it possible to carry out any random prior machining operation on the predimensioned flat metal sheet, without the machining operations being impaired by the bending or welding operation. The process is applicable to the production of front ferrules for casings surrounding the coldest pipe of a double flow turbojet engine.

Abstract: A sealing connector for joining ends of two conduits is disclosed in which a collar is rotatably retained on an end of one of the conduits and is threaded onto the end of the other conduit to bring the sealing surfaces of the conduit ends into contact with each other. The collar has an end face and an internal shoulder facing in opposite directions such that the shoulder faces in the direction of movement as the collar is threaded onto the conduit end. A resilient ring member is located between the shoulder of the collar and the end of the conduit to which it is rotatably retained such that the resilient ring member is compressed during the connecting operation. Such compression causes deformation of the ring member which, in turn, causes a leg projecting from the ring member to come into contact with the collar and to extend beyond the end face of the collar.

Abstract: A gas turbine engine is disclosed having an air compressor and a generally annular combustion chamber, with a generally annular diffuser located between the compressor and the combustion chamber so as to direct air exiting from the compressor toward the combustion chamber. The diffuser has inner and outer walls and defines an exit which is located adjacent to an opening in an upstream wall portion of the combustion forming a dome cowl. The dome cowl divides the air emanating from the diffuser exit into a primary air stream passing through the opening and one or more secondary air streams which pass between the walls defining the combustion chamber and the walls of a casing enclosing the combustion chamber assembly. A guide is associated with the diffuser for directing water in the air passing through the diffuser away from the opening such that it will not pass directly into the combustion chamber.

Abstract: A generally annular combustion chamber for a gas turbine engine is disclosed in which a plurality of generally cylindrical walls extend forwardly from an upstream end wall of the combustion chamber such that each cylindrical wall defines a cavity which is in communication with the interior of the combustion chamber. A first fuel injection head is located in each of the cylindrical walls so as to inject fuel into the cavity which is mixed with air and passes into the combustion chamber. The first fuel injection heads are located at a first axial position with respect to a longitudinal axis passing through the combustion chamber. A plurality of second fuel injection heads are located adjacent to the upstream end wall of the combustion chamber so as to spray fuel directly into the combustion chamber. The second fuel injection heads are located axially downstream of the axial positions of the first fuel injection heads.

Abstract: A gas turbine engine combustion chamber is disclosed having multiple sets of fuel injectors. A set of first fuel injectors are arranged in two radially inner and outer generally circular first arrays such that the fuel injectors of one array are located circumferentially between the fuel injectors of the other array. The combustion chamber also includes a set of second fuel injectors which are also arranged in two generally circular, radially inner and outer arrays such that, in each array, the second fuel injectors are located circumferentially between the first fuel injectors. In a circumferential direction, the positions of the first and second fuel injectors vary between the radially outward array and the radially inward array. One set of fuel injectors may operate under idle and low power operating conditions, while the other set of fuel injectors inject fuel into the combustion chamber during full power take off or cruise operations.

Abstract: A stator for a turbo-engine and a method for mounting the stator serve to improve fixing of the vanes of the stator and resistance of these vanes to impact in the event foreign bodies enter the turbo-engine. The stator includes several vanes radially maintained by their external and internal pivots between an internal ferrule and an external casing. The internal ferrule includes at least one bore intended to receive one of the internal pivots and the external casing includes a mechanism for the radial positioning and locking of the vane so as to make it possible to keep the internal pivot of the vane in the bore.

Abstract: A method and apparatus of molding articles from composite materials are disclosed in which a stack of prepregs are placed on a first forming surface of a former, which forming surface has a surface configuration matching that of one side of the composite article, placing a semi-rigid molding shelf onto the former such that a second forming surface of the molding shell, which matches the surface configuration of an opposite side of the composite article, bears against the stack of prepregs and urging the molding shell towards the former, thereby compressing the plies of prepregs by drawing a vacuum between an impermeable membrane covering the molding shell and the former. The assembly of the former, the molding shell, the stack of prepregs and the impermeable membrane are placed in an autoclave such that it may be heated while the vacuum is drawn between the membrane and the former to compress the stack of plies of prepregs.

Abstract: A fluid cooled guide vane is disclosed for use in a gas turbine engine which defines a plurality of separate cooling circuits to guide a cooling fluid through the interior of the vane, while at the same time minimizing the pressure drop of the cooling fluid as it passes through the vane. Each cooling circuit has a cooling fluid inlet, a cooling fluid outlet, a cavity and a chamber which is in fluid communication with the cavity and either the fluid cooling inlet, or the fluid cooling outlet. The multiple chambers are located in mounting bases attached at either end of the vane. The mounting bases define the several chambers as well as the cooling fluid inlets. The cooling fluid outlets may either be defined by the mounting bases, or may be formed by rows of orifices through the vane wall in communication with the cavities within the vane.

Abstract: A casing structural arm of a turbo-engine is fixed between an external ferrule and a hub of the casing and is formed as a composite material. The arm has one leading edge, one trailing edge, one radially external edge and one radially internal edge. These four edges define the four corners of the arm and securing of the arm to the ferrule and said hub is ensured by two pairs of linking braces respectively secured to the four corners of the arm.

Abstract: A stemmed blade for flow-straightener blading of a gas turbine engine includes at least one shank at the head of the blade forming a stem for use in fixing the blade. The shank has a notched portion situated adjacent the head of the blade and an end portion separated from the notched portion by a zone of lower tensile strength. Fixing of the blade to the engine casing is carried out by fitting the blade in position with the shank projecting radially outwards through a hole in the casing and then crimping a bush on to the notched portion of the shank using a suitable crimping tool which exerts a compressive force on the bush while exerting a traction force on the end of the shank until the zone of lower tensile strength breaks.

Abstract: A system is disclosed for detecting a malfunction in a fuel/lubricating oil heat exchanger which includes a pressure differential generator located in the pressure balancing conduit connecting the lubricating oil reservoir with the lubricating enclosure. The pressure differential generator may be a cavitation venturi tube having a throat which, under normal conditions, allows sub-sonic fluid flow which enables the air in the lubricating enclosure to freely communicate with the interior of the oil reservoir and vice versa. When fuel is mixed with the lubricating oil, due to a malfunction in the fuel/oil heat exchanger, the fuel enters the lubricating oil reservoir causing the fluid level within the reservoir to rise and overflow. The cavitation venturi tube is then supplied with a comparatively hot mixture of fuel and oil having a vapor pressure approximately equal to the reference pressure within the lubricating enclosure.

Abstract: A combustion chamber structure wherein the combustion chamber extends around a central, longitudinal axis and has primary oxidizer intake passageways whose positions along the central axis relative to an end of the combustion chamber are adjustable depending upon the operating conditions of the gas turbine engine. By controlling axial positions of the primary oxidizer intake passageways, the dwell time of the combustion gases and primary oxidizer inside the combustion zone of the chamber may also be controlled so as to increase the stability of the combustion, while at the same time minimizing the polluting emissions. The invention also encompasses the concept of adjusting the cross-sectional area of the primary oxidizer intake passageways as their positions along the central axis are adjusted. This enables a more accurate control of the volume of the primary oxidizer flow in addition to controlling the location of the flow.

Abstract: A turbojet propulsion engine for supersonic aircraft has a primary unit including a compressor, a combustion chamber, a turbine which drives the compressor, and an exhaust assembly, and a secondary unit including a compression fan assembly arranged in an annular secondary duct surrounding the primary unit, the fan assembly having at least one stage of rotor blades rigidly connected to the shaft which drives the compressor of the primary unit and is disposed between an upstream stage of fixed inlet guide vanes and a downstream stage of fixed flow straightener vanes, the inlet guide vane stage and the flow straightener vane stage each being associated with an adjuster for adjusting the pitch of the respective vanes.

Abstract: A gas separation assembly for a gas turbine engine combustion chamber is disclosed having spaced apart partition walls which extend through an end of the combustion chamber so as to define an oxidizer chamber which communicates with a source of oxidizer. Downstream ends of the spaced apart partition walls within the combustion chamber are interconnected to a plurality of generally "V" shaped spacers oriented such that the apex of the "V" configuration faces toward the end of the combustion chamber. Downstream edges of the partition walls are notched, also in a "V" shaped configuration such that the notches extend between opposite legs of the spacers. The spacers are circumferentially spaced apart so as to define passageways which communicate with the oxidizer chamber to enable oxidizer to pass through the gas separation assembly into the combustion chamber.

Abstract: A turbine casing includes circumferential walls delimiting an annular stream for the flow of gases. The radial arms traversing the stream are completed by a channeling part on the downstream side which is bolted to the arms. The walls are formed of butt-joined tiles assembled together and joined to collars situated on the arms and the channeling parts by riveted ridge tiles. The invention results in a reduction of resistance to the flow of gases, as well as absorption without the production of excessive stresses of the original thermic dilations in the walls.

Abstract: A rotary valve assembly is disclosed in which a rotary valve member is located within a casing having one or more fluid inlets and a plurality of fluid outlets. The rotary valve member has a fluid conduit which extends in a generally radial direction and which communicates with the fluid inlet. Fluid orifices communicate with the fluid conduit and exit through opposite sides of the rotary valve member to thereby minimize, or eliminate altogether, axial forces acting on the rotary valve member. Fluid outlet passages communicate with the two fluid orifices during at least part of the rotation of the rotary valve member to direct the pressurized fluid to the valve outlets. The rotary valve may include a pair of rotary valve members drivingly connected to each other such that they rotate synchronously. The connection may include gear teeth formed on the adjacent peripheries of the rotary valve members such that rotation of one of the valve members causes rotation of the other.

Abstract: A gas turbine blade includes a central core covered by a plurality of layers of composite material, and optionally also an outer sleeve of woven composite material. A network of transverse seams pass through the layers of composite material, and preferably also the core and the outer sleeve. This construction is particularly applicable to large diameter turbine blades.

Abstract: An apparatus for simultaneously molding separate portions of an article which may be subsequently assembled to form the complete separable article. The apparatus includes separate mold portions which, when assembled, define a molding cavity in which each of the mold portions has an outwardly extending flange. The mold portions are fastened together such that the flanges are spaced apart a distance at least twice as great as the thickness of the article to be molded. The mold portions extend along a longitudinal axis and each defines a molding surface which extends around the axis less than 360.degree.. When the mold portions are assembled, the molding surfaces extend completely around the longitudinal axis. The mold also includes silicone bead elements extending along the longitudinal axis in the space between the spaced apart flanges.