Chemical vapor infiltration densification method using single-pile plates for a semi-forced flow

A method for densification by pressure gradient chemical vapor infiltration of porous annular substrates having a central passage, the method comprising:

• providing a plurality of stacks of porous annular substrates, each stack comprising an internal volume formed by the central passages of the stacked substrates,
• providing a plurality of individual modules, each individual module comprising a support plate and a single stack of porous annular substrates disposed on the support plate, the support plate comprising a gas inlet opening and an injection tube mounted on the gas inlet opening and extending into the internal volume of the stack disposed on the support plate between a first tube end connected to the support plate and a second tube end which is free, the injection tube further comprising gas injection orifices opening into the internal volume,
• forming, in a chamber of a densification furnace, a stack of individual modules, each first individual module stacked on a second individual module having its gas inlet opening of the support plate communicating with the second end of the injection tube of the second individual module on which it is stacked so as to permit circulation of a gas between the individual modules, and
• injecting into the internal volume of each stack of porous annular substrates a gas phase comprising a gaseous precursor of a matrix material to be deposited within the porosities of the substrates,
• wherein, in each individual module, each first porous annular substrate is supported on a second porous annular substrate, or supported on the support plate, by means of a sealing ring providing radial sealing between the first porous annular substrate and the second porous annular substrate or between the first porous annular substrate and said support plate, and each sealing ring is coupled to an annular spacer having an inner diameter equal to an inner diameter of the porous annular substrates, each annular space being surrounded by the sealing ring with which it is associated in a plane perpendicular to a direction in which the porous annular substrates are stacked, and having a thickness less than the thickness of the sealing ring with which it is coupled.