Abstract: The invention relates to a process and an apparatus for molding metals, alloys and plastics material under low pressure. A gas which is inert with respect to the material to be molded is injected at a controlled rate and in a controlled volume into the compression/expansion chamber of the apparatus during certain phases of the molding operation, while compressed air is used for establishing pressure in the chamber or furnace accommodating the crucible which contains the liquid material to be molded. By virtue of the invention, it is possible to avoid oxidation phenomena and to improve the quality of the moldings.

Abstract: The invention relates to a process for continuously circulating a fluidized powder in a heat exchanger between a heat-carrying gas and a fluidized powder, and to heat exchangers using this process. In the process according to the invention, the circuit through which the fluidized material circulates is in the form of two series of tubes, merely one series of ascending tubes and another series of descending tubes, and the material is fluidized in these tubes with a density that is higher in the descending tubes than in the ascending tubes. The invention applies to any heat exchanger between a gas and a powder and, more particularly, to installations, for calcining hydrated alumina.

Abstract: The invention relates to the pneumatic conveyance of powdered materials comprising a conveyor duct balanced by a fluidized feed column and a transfer chamber, the gravimetric rate of flow of material is regulated by a means of control designed to maintain a set value of pressure in the feed circuit to an injector by means of a device controlling the supply to the feed column.

Abstract: The invention concerns an improved injection device for molding machines with a cooling chamber for casting of non-ferrous metals and alloys. It is characterized by a two-part piston, one part of which slides freely and coaxially inside the other, forming a chamber in which a gas, neutral with respect to the metal to be cast, is compressed by the forward movement of the piston by virtue of a stop-pin, then liberated and expanded at the end of injection in a container of liquid metal where it causes a balancing force effect and improves the filling of the mold.This device makes it possible to eliminate the "ramroddings" which occur in single-piston machines at the end of injection and to obtain cast products which are free of defects.