Production of internal atmospheres for kilns

An apparatus for controlling the internal atmosphere of a kiln comprising:

• a. an elongated gas flow chamber having a first end which carries an inlet thereto and a second end which carries an outlet therefor;
• b. a thermal reaction chamber communicating with said outlet at said second end of said elongated gas flow chamber and having an outlet spaced in alignment therefrom;
• c. air injection means for injecting air into said elongated gas flow chamber through said inlet thereof toward said outlet thereof from points uniformly about the inner pheriphery of said elongated gas flow chamber;
• d. an air flow source connected to said air injection means and comprising a valve means and a first flow rate sensing means having an input and an output;
• e. first gas nozzle means positioned adjacent said second end and around said elongated gas flow chamber and directed into said elongated gas flow chamber and towards said thermal reaction chamber for passing a fuel gas thereto;
• f. a fuel gas source connected to said first gas nozzle means and comprising a valve means and a second flow rate sensing means having an input and an output;
• g. a flow ratio control means operatively connected with the outputs of said first and second flow rate sensing means of said air flow source and said fuel gas source for controlling the relative amounts of air, and fuel gas which are injected into said gas flow chamber;
• h. second gas nozzle means positioned adjacent said first gas nozzle means and around said elongated gas flow chamber and directed into said elongated gas flow chamber and toward said thermal reaction chamber for injecting inert gas therein;
• i. a furnace chamber having an inlet and outlet with its inlet operatively communicating with the outlet of said thermal reaction chamber;
• j. conduit means connecting the outlet of said furnace chamber with a kiln;
• k. an inert gas source connected with said second nozzle and comprising a valve means and a temperature control means operatively connected with said valve means such that the amount of the inert gas injected into said elongated gas flow chamber can be varied in response to fluctuations in the temperature of the gas passing through said conduit means connecting the outlet of said furnace chamber with said kiln;
• and
• l. temperature control means operatively connected with the valve means of said fuel gas source for sensing the temperature in said kiln and varying the amount of fuel gas injected into said elongated gas flow chamber in response thereto.

A process for producing atmospheres for kilns comprising:

• a. creating an elongated air flow zone the outlet of which communicates with a thermal reaction zone wherein air is passed uniformly about the inner periphery of said air flow zone, toward said thermal reaction zone, in a parabolic velocity front;
• b. injecting a fuel gas, in a controlled amount, from points radial of said elongated air flow zone and adjacent its outlet in a manner such that said fuel gas impinges the air being passed in said thermal reaction zone;
• c. injecting an inert gas in a controlled amount from points adjacent to the points of injection of said fuel gas and in substantially the same direction as said fuel gas;
• d. igniting the mixture of fuel gas, air, and inert gas in said thermal reaction zone to produce an atmosphere of desired composition;
• and
• e. passing said atmosphere of desired composition into a kiln.