Method and apparatus for hot isostatic pressing

A method of hot isostatic pressing by a hot isostatic pressing system including a hot isostatic pressing station and at least first, second and third auxiliary stations, said method including repeating a cycle of operation which comprises:

• a first step of loading into said hot isostatic pressing station a first container accommodating a first work item and an internal heater within a heat insulating wall to subject said first work item to hot isostatic pressing treatment including inert gas purge, heating and pressurization, maintaining high temperature and pressure, and depressurizing, while simultaneously preheating a second work item in an inert gas atmosphere in a second container similar to said first container loaded into said second auxiliary station, and cooling a treated third work item in an inert gas atmosphere in said third auxiliary station;
• a second step of, upon depressurizing of said hot isostatic pressing station to atmospheric pressure, unloading said first work item from said isostatic pressing station together with the internal heater and a surrounding hot inert gas atmosphere substantially in a shielded state within the heat insulating wall and loading said first work item into said first auxiliary station, while unloading said second work item from said second auxiliary station together with the internal heater and surrounding hot inert gas atmosphere substantially in a shielded state within the heat insulating wall for loading into said hot isostatic pressing station, and replacing the cooled third work item by a fourth work item;
• a third step of subjecting said second work item to a hot isostatic pressing treatment in the same manner as in said first step, while preheating said fourth work item at said third auxiliary station, and cooling said first work item at said first auxiliary station;
• a fourth step of unloading said second work item and the internal heater from said hot isostatic pressing station in the same manner as in said second step and loading second work item into said second auxiliary station, unloading said fourth work item and the internal heater from said third auxiliary station and loading said fourth work item into said hot isostatic pressing station, and replacing the treated first work item by a fifth work item;
• a fifth step of subjecting said fourth work item to a hot isostatic pressing treatment in the same manner as in said first step, while preheating said fifth work item at said first auxiliary station, and cooling said second work item at said second auxiliary station;
• and
• a sixth step of unloading said fourth work item and an internal heater from said hot isostatic pressing station and loading said fourth work item into said third station in the same manner as in said second step, unloading said fifth work item and internal heater from said first auxiliary station and loading said fifth work item into said hot isostatic pressing station, and replacing the treated second work item by a sixth work item.

A hot isostatic pressing system comprising:

• a hot isostatic pressing station including a high pressure container which further comprises a vertical pressure cylinder closed at the upper end thereof and a lower lid member detachably fitted to a bottom portion of said pressure cylinder, a treating chamber internally provided with a heater and enclosed by a heat insulating wall, and means for controlling pressure and temperature under a condition suitable for hot isostatic pressing of a work item accommodated in said treating chamber;
• a plurality of auxiliary stations each of which has an opening formed therein for receiving from beneath thereof said heat insulating wall of said treating chamber accommodating said internal heater and said work item and each of which further comprises a support structure for supporting said heat insulating wall and means for cooling said work item and internal heater in an inert gas atmosphere;
• a carriage for transferring said lower lid and work item or said lower lid, said work item, said heat insulating wall and said internal heater between said hot isostatic pressing station and one of said plurality of auxiliary stations;
• and
• a lift mechanism for lifting up and down said lower lid and work item or said lower lid, work item, heat insulating wall and heater at said hot isostatic pressing station and each one of said plurality of auxiliary stations.