Heat treating apparatus

Apparatus for heat treating a heat treatable material, said apparatus comprising:

• a housing having an upper opening for receiving a heat treatable material at a first temperature, a lower opening, and a chamber therebetween in which the heat treatable material is heated to a second temperature higher than the first temperature to thereby form a heated material as the heat treatable material moves from the upper opening to the lower opening;
• a plenum connected to the lower opening of said housing, said plenum having a vertical throughhole in communication with the lower opening of said chamber, an interior annular cavity extending around said throughhole, an inlet port in communication with said annular cavity and a plurality of spaced apart channels arranged radially around said throughhole and fluidly connecting said throughhole with said annular cavity;
• and
• a gas supply assembly operatively connected to the input port of said plenum, for generating a heated gas flow through the plenum and upwardly through said chamber from the lower opening to the upper opening, said heated gas flow having a temperature sufficient to heat the heat treatable material within the chamber to said second temperature, and a sufficient flow velocity for selectively sustaining the heat treatable material afloat in the chamber until the heat treatable material reaches the second temperature, and forms the heated material which passes through the lower opening and the throughhole of said plenum.

A method for heat treating a heat treatable material, said method comprising the steps of:

• a) passing the heat treatable material through a housing from an upper opening at a first temperature through a chamber to form a heated material and passing the heated material out of a lower opening;
• b) passing a heated gas through a plurality of pathways into the chamber to generate a flow of the heated gas countercurrent to the direction of the heat treatable material as it passes from the upper opening to the lower opening to thereby form the heated material in a manner such that the heated material leaves the lower opening at a second temperature higher than the first temperature;
• c) establishing a flow velocity of the heated gas sufficient to suspend discrete portions of the heat treatable material for a sufficient time for the heated gas to heat the heat treatable material and form the heated material at the second temperature;
• and
• d) controlling the conditions within the chamber to enable the heat treatable material to attain the second temperature.