Patent ID: 6881268

Claim:
An apparatus for forming a desired gas atmosphere, comprising: a casing having a gas introduction opening for introducing a gas into said casing and a gas discharge opening for discharging the gas from said casing; a gas circulating tube passage fluidly communicating with said casing for effecting circulation of the gas; a circulating fan for effecting circulation of the gas in said casing through said gas circulating tube passage; a valve switchable between a position for introducing and discharging the gas into and from said casing through said gas introduction opening and said gas discharge opening and a position for effecting circulation of the gas in said casing through said gas circulating tube passage; a trap provided in said gas circulating tube passage for cooling the gas and condensing moisture contained in the gas passed through said circulating tube passage and for removing the moisture from the gas; and a heat exchanger for effecting heat exchange between the gas flowing into said trap and the cooled gas flowing out of said trap.