METHOD FOR PREVENTING ABNORMAL EXPANSION OF CAPSULE AND CAPSULE

摘要

PURPOSE:To prevent the failure of a pressing device owing to the abnormal expansion or explosion of a capsule in the stage of compacting powder under the hydrostatic pressure of a gaseous material by opening a hole with a punching member when leakage arises in the capsule contg. the powder and the capsule begins to expand. CONSTITUTION:A heat shielding body 3 and a heater 4 of an electric heating wire or the like is placed in a pressure resistant vessel 1 having a cover body 2, and a capsule 5 which is formed of a metal, rubber, glass, etc., and contains powder 6 to be molded by compaction is placed therein. The vessel 1 is hermetically closed and while the vessel is heated with the heater 4, gas such as N2, Ar, He, or the like in a storage tank 9 is forced by a compressor 8 into the vessel and the powder 6 is molded under the pressure via the capsule 5. If there is leakage in the capsule 5 in this stage, the high pressure gas enters the inside of the capsule and the capsule expands abnormally or explodes on account of a pressure difference in the stage of reducing the pressure, thus breaking the heater and others. The top end plate 13 of the capsule 5 is thinly formed to allow this part to expand first and holes are punched by punching members installed at a space C, by which the internal pressure of the capsule is quickly reduced and the abnormal expansion and explosion of the capsule 5 are prevented.