Patent ID: 7625204

Claim:
A gas cooling type vacuum heat-treating furnace incorporating a gas cooling furnace for cooling an article which has been heated, with pressurized circulation gas, characterized in that the gas cooling furnace comprises a cooling gas surrounding a cooling zone where the article to be heat-treated is stationarily set, and defining therein a vertical gas passage having a constant cross-sectional area, a gas cooling and circulating device for cooling and circulating gas vertically flowing in the cooling chamber, a gas direction switching device for switching directions of gas vertically flowing in the cooling chamber, and upper and lower straighteners blocking upper and lower ends of the cooling chamber, for causing a flowing velocity distribution of the gas passing therethrough to be uniform, wherein the gas cooling and circulating device comprises a cooling fan arranged adjacent to the cooling chamber, for sucking and pressurizing the gas having passed through the cooling chamber, and a heat-exchanger for indirectly cooling the gas sucked in to the cooling fan, and wherein the gas direction switching device incorporates a hollow cowling surrounding the heat-exchanger, being spaced therefrom, and an elevating cylinder for moving the cowling up and down, the cowling has a lower suction port which is communicated with a lower part of the cooling chamber at a downward position, and an upper suction port which is communicated with an upper part of the cooling chamber at an upward position.