Abstract: The invention relates to an installation for impregnating powder on at least one substrate to be treated of the yarn and/or tape type. The installation includes a powder delivery unit, a unit supplying the substrate to be treated, at least two electrodes and a circulation zone for the powder and the substrate to be treated. The installation also includes a containment unit having an inlet orifice for the substrate to be treated and the powder, an outlet orifice for the impregnated substrate and a contour area closed from the inlet orifice to the outlet orifice. The circulation zone is formed by the internal volume of the containment unit, and the confinement unit is fixed with respect to at least one of the electrodes. The substrate to be treated and the powder are mobile, in the circulation zone, between the inlet orifice and the outlet orifice of said confinement unit.

Abstract: An installation for impregnating a porous substrate by transfer of powder, including an area for storing the powder, and an endless conveyor capable of being moved, which includes an external surface containing cavities. The external surface of the conveyor delimits an edge of the storage area to fill said cavities with the powder. The installation comprises a positioner for holding the porous substrate in contact with a fraction of the conveyor length, to seal cavities containing the powder. A drive device enabling to move the conveyor and the porous substrate, and means for displacing the powder are arranged opposite said fraction of the conveyor length, to at least partly displace a portion of the powder across the porous substrate.

Abstract: Apparatus for impregnating a porous medium with powder, including a device able to generate an alternating electric field through the porous medium, the device including a first electrode and a second electrode, which are placed on either side of the porous medium, the apparatus being characterized in that: the first electrode is covered with a screen making contact with the electrode, said screen having a dielectric strength higher than 6 kV/mm; and the second electrode is covered with a protective layer, said protective layer having a superficial resistivity higher than 1×1012?/?.

Abstract: An installation for impregnating a porous substrate by transfer of powder, including an area for storing the powder, and an endless conveyor capable of being moved, which includes an external surface containing cavities. The external surface of the conveyor delimits an edge of the storage area to fill said cavities with the powder. The installation comprises a positioner for holding the porous substrate in contact with a fraction of the conveyor length, to seal cavities containing the powder. A drive device enabling to move the conveyor and the porous substrate, and means for displacing the powder are arranged opposite said fraction of the conveyor length, to at least partly displace a portion of the powder across the porous substrate.

Abstract: This impregnation device comprises at least a first dielectric insulating screen and first and second opposite-facing electrodes which are separated by a passage for the porous material to be impregnated provided with powder and are capable of producing an alternating electric field in this passage after having been connected to an alternating voltage generator. At least first electrode comprises at least two conducting strips, each of which has an internal face covered by the first dielectric screen and, overall, is turned towards the second electrode and also a longitudinal edge running along a separating slot, which strips are separated from each other by this separating slot and are electrically connected to one another.

Abstract: A process for producing a stampable reinforced composite semi-finished product comprising one or more plastics and chopped fibers or continuous filaments, the softening temperature of which is above the highest of the softening temperatures of the materials, comprises the steps of: depositing the fibers or filaments, especially by gravity, onto a conveyor; sprinkling particles of a powder of the plastics onto the fibers or the filaments, in a proportion of between 5% and 90% of the total weight; blending the particles with the fibers or the filaments; and heating the blend to a temperature above the softening temperatures of the materials. The blending step includes subjecting the blend to at least one electric field approximately perpendicular to the direction of advance of the conveyor.

Abstract: This impregnation device comprises at least a first dielectric insulating screen and first and second opposite-facing electrodes which are separated by a passage for the porous material to be impregnated provided with powder and are capable of producing an alternating electric field in this passage after having been connected to an alternating voltage generator. At least first electrode comprises at least two conducting strips, each of which has an internal face covered by the first dielectric screen and, overall, is turned towards the second electrode and also a longitudinal edge running along a separating slot, which strips are separated from each other by this separating slot and are electrically connected to one another.

Abstract: A process for producing a stampable reinforced composite semi-finished product comprising one or more plastics and chopped fibres or continuous filaments, the softening temperature of which is above the highest of the softening temperatures of the materials, comprises the steps of: depositing the fibres or filaments, especially by gravity, onto a conveyor; sprinkling particles of a powder of the plastics onto the fibres or the filaments, in a proportion of between 5% and 90% of the total weight; blending the particles with the fibres or the filaments; and heating the blend to a temperature above the softening temperatures of the materials. The blending step includes subjecting the blend to at least one electric field approximately perpendicular to the direction of advance of the conveyor.

Abstract: The invention relates to a novel electric powder impregnation process for impregnating powder into a fibrous, filamentary and/or porous network, especially in order to produce a composite, comprising a continuous, rigid or flexible, matrix with which said network is in intimate contact, in which process the powder on the one hand and said network on the other are placed between a lower electrode and an upper electrode, these electrodes are electrically insulated from each other by a dielectric and connected to the respective poles of an AC generator so as to simultaneously subject the powder and said network to an electric field, characterized in that the upper electrode comprises at least one electrode tube and the AC electric field applied is from 0.10 to 20 kV/mm.

Abstract: The invention relates to a novel electric powder impregnation process for impregnating powder into a fibrous, filamentary and/or porous network, especially in order to produce a composite, comprising a continuous, rigid or flexible, matrix with which said network is in intimate contact, in which process the powder on the one hand and said network on the other are placed between a lower electrode and an upper electrode, these electrodes are electrically insulated from each other by a dielectric and connected to the respective poles of an AC generator so as to simultaneously subject the powder and said network to an electric field, characterized in that the upper electrode comprises at least one electrode tube and the AC electric field applied is from 0.10 to 20 kV/mm.

Abstract: In the jig type textile finishing method and apparatus of the invention, the textile material (19) passes through a heated treatment bath (20) and is rolled alternately in one direction and in the opposite direction with high frequency or microwave electromagnetic waves (24) being applied to said textile material (19) while it is being rolled in and/or out. The power of the waves is determined, as a function of the optimum temperature for the reaction that is to be implemented, in such a manner as to maintain the temperature of the assembly (5, 6) constituted by the rolled-in textile material and the bath in which it is impregnated substantially equal to or greater than said optimum temperature.

Abstract: In the jig type textile finishing method and apparatus of the invention, the textile material (19) passes through a heated treatment bath (20) and is rolled alternately in one direction and in the opposite direction with high frequency or microwave electromagnetic waves (24) being applied to said textile material (19) while it is being rolled in and/or out. The power of the waves is determined, as a function of the optimum temperature for the reaction that is to be implemented, in such a manner as to maintain the temperature of the assembly (5, 6) constituted by the rolled-in textile material and the bath in which it is impregnated substantially equal to or greater than said optimum temperature.