High pressure apparatus : ram-in-tie-bar multianvil presses

Abstract

A multiaxial press is described in which pressing members such as anvils, punches, pistons, and dies are brought together along a plurality of geometrical axes by a contracting framework. These pressing members impinge upon an appropriate cell to generate pressure. The cell and/or its contents may be heated or cooled while under pressure by external or internal means. The preferred embodiment of this apparatus can be envisioned by substituting pull-type hydraulic rams for the fixed, rigid tie bars of a conventional multianvil press such as a tetrahedral press. Thus the "Ram-In-Tie-Bar" (RITB) press has variable length tie bars. The base mounted push-type ram of the conventional press is replaced by a fixed post to which an anvil is attached. The new press has a number of advantages over conventional multianvil presses which are equipped with an anvil guide: (1) The Ram-In-Tie-Bars serve as an integral anvil guide, thus eliminating the need for the usual guide. This greatly increases the working space in the anvil region and facilitates the use of X-ray diffraction devices and other equipment in conjunction with the press. (2) The total ram tonnage required to obtain the same anvil load is reduced. Thus total RITB tonnage for a tetrahedral system is only 0.6123 that of a standard (rigid tie means design) tet press and for a cubic system is only 0.7071 times the total ram tonnage of a standard cubic press. (3) Larger presses of RITB design can be built than can be built in standard design (4) RITB presses are less expensive than conventional types, especially in the larger sizes. (5) The use of external heating and cooling is greatly facilitated in the new press.