Abstract: Oven for dehydrating pulverulents, sand or granules, comprising an energy-saving dehydration device, adapted to gypsum burning. The device consists of an outer casing, an inner casing and flow cones disposed on said casings. A burner and a lock complete the device. Pressure within the oven is increased by the provision of a cover, a gypsum lock and a steam valve. The process takes place in dry or moist conditions, the latter being advantageous for the processing of insulating products or for gypsum amending the nature of plaster. Heat exchange enables the products to be processed at low temperatures. The central combustion chamber prevents loss by radiation. Application to gypsum burning, during which the device has demonstrated energy savings of 50% in comparison with traditional appliances.

Abstract: An expansible mold for the fabrication of plaster parts having reliefs in the side walls comprising at least two walls and non-compressible deformable parts between two parallel side edges of the walls in which, under pressure, the deformable parts acquire the profile to be imparted to the molded plaster part, and which retract from the molded plaster part upon release of pressure to enable removal of the molded part without loss of a tight sealing relation with the mold.