Process and installation for cooling workpieces with gases

摘要

Cooling (esp. quenching) of workpieces by gases takes place in a heat treatment furnace (1) in which the circulating gases are cooled down on cooling surfaces (12) of at least one heat exchanger (11) located in the furnace and joined by piping (13a,13b) to an external heat extraction unit (17) with a liquid cooling medium. The storage volume (20) for a hydrous cooling medium in this unit is kept under a reduced pressure so that at least a part of the hydrous phase of the volume (20) is evaporated for extraction of heat from the heat exchanger (11). The tank (18) for the storage volume is connected to a vacuum pump (24).