Method and apparatus for controlling flow bias in a multiple zone process

An apparatus for controlling fluid flow bias within a multiple zone furnace chamber having a free flow of non-air containing gas atmospheres from one zone to another therein, comprising:

• (a) sampling means for withdrawing a sample of non-air containing atmosphere from within at least one of said zones;
• (b) means for analyzing said non-air containing atmosphere sample for at least one chemical or physical property that is indicative of the existing flow bias, or of a change in said flow bias, in the zone from which said sample was withdrawn;
• (c) means for comparing the property value, or change in property value, obtained upon the analysis of step (b) above with a reference set point or range for said property, or change of property;
• and
• (d) means for injecting a non-air containing fluid into one of said zones of non-air containing gas atmospheres so as to actively apply a force within one of said zones in response to said comparison of the analyzed property value, or change in property value, with the reference set point or range, thereby controlling the fluid flow bias within said zones to conform the analyzed property with said reference set point or range, whereby fluid flow bias within the multiple zone furnace is conveniently controlled without the introduction of air into the multiple zone furnace or into the gas analysis sample and system employed for such control purposes.