PROBLEM TO BE SOLVED: To provide a vacuum cooling device lessening deviation between a tank pressure and a target pressure to increase accuracy of pressure control in the case of performing slow cooling operation and slow returning operation with the vacuum cooling device.SOLUTION: A vacuum cooling device performs slow cooling by vacuumizing the inside of a cooling tank 2. The vacuum cooling device performs slow cooling operation of decreasing a pressure reducing speed by setting slow cooling piping 4 having a slow cooling valve 3 in the middle and introducing slow cooling air through the slow cooling valve 3 when vacuum cooling, and in vacuum cooling operation, compares a detected cooling tank pressure with a target pressure set corresponding to an elapsed time, and adjusts an opening degree of the slow cooling valve so as to make a tank pressure close to a target pressure. When performing slow cooling operation, it is set that an opening degree of the slow cooling valve becomes larger in a period when a cooling tank vacuum degree is lower, and an opening degree of the slow cooling valve becomes smaller as a vacuum degree in the cooling tank increases by progress of vacuum cooling operation.COPYRIGHT: (C)2013,JPO&INPIT【課題】真空冷却装置で徐冷運転や徐戻し運転を行う場合に、槽内圧力の目標圧力とのずれを少なくし、圧力制御の精度を高める。【解決手段】冷却槽2内を真空化することで冷却を行う真空冷却装置であって、途中に徐冷弁3を持った徐冷用配管4を設け、真空冷却時に徐冷弁3を通じて徐冷用の空気を導入することによって減圧速度を低下させる徐冷運転を行えるようにしており、真空冷却運転時には、検出した冷却槽内圧力と、経過時間に対応させて設定しておいた目標圧力を比較し、槽内圧力が目標圧力に近づくように徐冷弁の開度を調節するようにしている真空冷却装置において、徐冷運転を行う場合、冷却槽内の真空度が低い時期には徐冷弁の開度が大きくなるようにしておき、真空冷却運転が進むことで冷却槽内の真空度が高くなるにつれて、徐冷弁の開度は小さくなっていくように設定する。【選択図】図1
