A CHEMICAL VAPOR INFILTRATION (CVI) FURNACE AND A PROCESS FOR CONTROLLING DISTRIUBUTION OF PREHEATED REACTIVE GAS IN A CVI FURNACE

摘要

The present invention relates to a gas preheater for a CVI furnace designed for the densification of annular porous substrates arranged in a plurality of vertical annular stacks of substrates, comprising : a sleeve made of heat conductive material resting upon the bottom wall of a susceptor and delimiting a gas preheating chamber, with a gas inlet opening in the gas preheating chamber ; a heat exchange assembly located in the gas preheating chamber ; a gas distribution plate resting upon the sleeve, covering the gas preheating chamber and provided with a plurality of passages for preheated gas ; a load supporting plate for supporting stacks of annular substrates and provided with a plurality of passages in communication with respective passages of the gas distribution plate and registration with internal volumes of respective stacks of annular substrates ; and nozzles inserted in passages communicating the gas preheating zone with the internal volumes of respective stacks of annular substrates for adjusting the flows of preheated gas respectively admitted in said internal volumes.