GB1409410A - Method and apparatus for rapid isostatic pressing - Google Patents

Abstract

1409410 Isostatic compaction NATIONAL FORGE CO 30 April 1974 [11 May 1973] 18932/74 Heading B5A A method of isostatically pressing a porous body, e.g. of metallic powder 48 in a plastic can 50, comprises heating the body to a temperature above that at which it is compressed and below its fusion temperature, inserting it in a pressure vessel 12 which is then closed and sealed by a plug 14, rapidly pumping liquid pressurizing medium into the vessel to fill it while avoiding contact of the liquid with the body until the vessel is substantially filled and then rapidly increasing the pressure, by pumping, to a level above the critical pressure of the liquid. The body is placed in a shielding container 38 whereby the pumped liquid fed through a port 20 overflows the container to contact the body when the space in the vessel is almost full; a pressure release device 36 is provided. On pressure release, the liquid is drained through a port 20, and liquid surrounding the body vapourizes. In a modification a cylindrical heat sink is located between the body and the shielding container and transfers heat to the body after the body is placed in the container. In Fig. 7 the body 80 is mounted on a support 74 and pressure liquid is fed tangentially to the pressure vessel wall through an inlet 72 ensuring that it does not contact the body until the vessel is substantially full. In Fig. 9, not shown, the liquid is supplied to a cylindrical pressure vessel via an inlet central of its base, and the vessel is rotated to centrifuge the liquid outwardly and upwardly along its wall.