CVI densification installation including a high capacity preheating zone

1. A thermochemical treatment installation comprising:

a reaction chamber;

at least one gas inlet; and

a gas preheater chamber situated between the at least one gas inlet and the reaction chamber, said gas preheater chamber having a plurality of perforated distribution trays held spaced apart one above another, wherein the gas preheater chamber also includes, between at least two facing perforated distribution trays of the plurality of perforated distribution trays, a plurality of walls defining flow paths for a gas stream between said plurality of perforated distribution trays, each wall of the plurality of walls extending vertically between said at least two facing perforated distribution trays, and wherein the plurality of walls comprises at least:

a first series of walls located in a center zone of each of the at least two perforated distribution trays; and

a second series of walls located in a periphery zone of each of the at least two perforated distribution trays, the first series and the second series being configured to create discontinuities in the flow paths of the gas stream.

2. An installation according to claim 1 , wherein the plurality of distribution trays are disk-shaped and wherein at least some of the plurality of walls extend between said plurality of distribution trays in a radial direction.

3. An installation according claim 2 , wherein a first number of walls of the second series of walls is greater than a second number of walls of the first.

4. An installation according to claim 1 , wherein at least some of the plurality of walls present an undulating shape.

5. An installation according to claim 1 , wherein the plurality of walls present thermal conductivity that is greater in a direction parallel to the plurality of perforated distribution trays than in a direction perpendicular to said plurality of perforated distribution trays.

6. An installation according to claim 5 , wherein the plurality of walls are made of composite material having fiber reinforcement densified by a matrix, and wherein the fiber reinforcement of the composite material extends for the most part in a direction parallel to the plurality of perforated distribution trays.

7. An installation according to claim 5 , wherein the plurality of walls are made of graphite. series of walls.

8. An installation according to claim 1 , further comprising a loading tray present above the plurality of perforated distribution trays of the gas preheater chamber, said loading tray being supported by columns passing through the plurality of perforated distribution trays.

9. An installation according to claim 8 , wherein the loading tray has a plurality of circular openings each serving to co-operate with a stack of annular fiber preforms for densifying.

10. An installation according to claim 1 , further comprising a susceptor having at least one side wall surrounding the gas preheater chamber and the reaction chamber, and an induction winding suitable for heating the at least one side wall by induction.

11. An installation according to claim 1 , wherein the plurality of walls further comprises:

a third series of walls located at an intermediate portion of each of the at least two perforated distribution trays.

12. An installation according to claim 11 , wherein:

the first series of walls comprises a first number of walls;

the second series of walls comprises a second number of walls; and

the third series of walls comprises a third number of walls such that the second number of walls is greater than the first number of walls and the third number of walls, and the third number of walls is greater than the first number of walls.

13. An installation according to claim 11 , wherein at least part of the intermediate portion is located between the center zone and the periphery zone.