摘要:
Pour fabriquer des pièces creuses par implantation de picots sur un mandrin, mise en place de fils selon au moins deux directions différentes dans des couloirs formés entre les picots, puis densification de la structure obtenue, on utilise un mandrin réalisé en un matériau dont la résistance à la compression est compatible avec les conditions d'implantation des picots et qui conserve son intégrité géométrique jusqu'à environ 700oC au moins. Ce matériau est, de préférence, un matériau minéral tel que de la silice. Il se présente sous la forme d'une mousse ou d'un feutre. Dans le cas d'un feutre, celui-ci est fixé sur un support interne par un adhésif résistant, de même que le support, à une température d'au moins environ 700oC. L'utilisation de ce type de matériaux permet de fabriquer en totalité les pièces sur un même mandrin, même lorsque ces pièces sont portées à une température de 700oC au moins, lors de leur densification.
摘要:
At least one second condensation vessel (40) is connected to a gas outlet pipe (45) from a first vessel (20) and contains a second gas outlet pipe (50). There are means of cooling the second vessel. - The apparatus comprises a first nebulizing and condensing vessel with an upper part (24) and a lower part (21) designed to contain the liquid medium. This has a gas supply pipe (35); means of nebulizing the liquid medium (31, 33) and a first outlet pipe (45) for the gaseous medium. There are means of placing the inside of the first vessel under vacuum or under pressure to allow the gaseous medium to penetrate into this first vessel, circulate in it and be evacuated in a continuous flow. The gas supply pipe to the first vessel has one end outside this vessel and a second end inside the vessel. The means of nebulizing comprise a nebulizing nozzle (31) which is placed at the level of the second end of the inlet pipe and has at least one orifice (32), and a nebulization tube (33) with two openings: one opening in the lower part of the first vessel and a second opening which sprays the orifice of the nebulization nozzle. The nebulization nozzle is made by a reduction in section of the gas supply pipe and is made of a piece fixed to the second end of the gas supply pipe. The orifice of the nebulization nozzle is orientated toward the upper part of the vessel and the second opening in the nebulization tube is immediately above this orifice. The first vessel has three parts: a reservoir (21) which forms the lower part of the vessel and which contains the liquid medium; a nebulization chamber (23) which forms the intermediate part of the vessel and in which are placed the orifice of the nebulization nozzle and the second opening of the nebulization tube; and a condensation dome (24) which forms the upper part of the vessel. The second vessel has a base (41) and a top (46). The first gas outlet pipe is a pipe with a bend which connects the nebulization chamber of the first vessel to the base of the second vessel. Alternatively, the orifice of the nebulization nozzle is orientated towards the lower part of the first vessel and the second opening of the nebulization pipe is placed immediately below the orifice. In this case, the first vessel is made of two parts: a reservoir which forms the lower part and which holds the liquid medium, with a base whose surface is less than a cross section of the reservoir; and a nebulization chamber forming the upper part of the vessel and containing the orifice of the nebulization nozzle and the second opening of the nebulization tube. The reservoir is funnel-shaped from bottom to top. The second vessel is cooled by a Peltier effect cell and contains a packing. The equipment is a compact structure which can be carried or towed by one person. The liquid medium contains one or more solvents such as water, organic solvents or a mixture thereof.
摘要:
In order to fabricate hollow parts by implementation of pins on a mandrel, setting in place wires according to at least two different directions along corridors formed between the pins, and densifying the obtained structure, a mandrel is used which is made of a material of which the compressive strength is compatible with the conditions of implementation of the pins and which keeps its geometrical integrity up to at least 700oC approximately. Said material is preferably a mineral material such as silica. It has the aspect of a foam or a felt. In the case of a felt, the latter is fixed to an inner support by means of an adhesive which, as well as the support, resists to a temperature of at least 700oC approximately. The utilization of this type of material enables to fabricate all parts on one same mandrel even when said parts are brought to a temperature of at least 700oC during their densification.