ES290077A1 - PROCEDURE FOR MANUFACTURING HOLLOW ARTICLES - Google Patents

Abstract

A method of making a hollow article in a die open at one end comprises immersing the open end of the die 5 to a controlled depth in a bath of molten material and conducting a predetermined quantity of a pressure fluid into the bath and below the die so as to form a bubble of the molten material and to apply the bubble against the inner surface of the die where it solidifies. The article may be closed by applying a plate 9, Fig. 4, to the open end of the die thereby trapping a layer 10 of the melt. The die may be a hallow metal, vitreous or glass object which is to be coated with an inner lining. The preferred melts are alloys e.g. of nickel, titanium, aluminium which when exposed to a fluid such as oxygen form a film-like layer of a compound such as an oxide on the surface of the bubble. The pressure fluid may contain constituents which become incorporated in the metal during blowing e.g. sulphur containing gases such as sulphur dioxide, hydrogen sulphide. Other fluids mentioned are inert gases such as helium, argon, CO2, CO, hydrocarbon gases such as methane and its combustion products, halohydrocarbons such as fluoro and chloro methane and ethane, halogens like chlorine, bromine, fluorine, hydrohalogens like hydrogen chloride, rare earth halides, like germanium chloride, metal-organic compounds etc. liquids such as silicone fluids or polysiloxanes which remain stable at the temperature of the melt or decompose to form gases or reactive elements, fluidized solids such as gases containing finely divided metal, metal oxide etc. Inert gas may be applied to the die interior, or suction to assist the pulling of the bubble thereinto. In a modification, Fig. 7, a globule 4 of glass or other vitreous material, high melting point plastic, metal or alloy, is placed on the end of the blow tube 2 and is blown into the die, the bubble picking up an adherent lining of aluminium alloy from the bath 1 so as to obtain a glass etc. lined aluminium alloy article. This article may then be used as a die for a subsequent blowing operation to produce for example a glass object having thin inner and outer layers of metal alloy. Alternately the bubble may be blown into a plastic, metal or metal alloy die which then forms part of an article having a glass-lined metal alloy coated insert. A machine for the continuous production of hollow articles from aluminium alloy comprises, Figs. 11, 13, a moult 33 vertically movable by rack and pinion 47, 48, a molten metal bath 31, and a blow pipe 26 to which predetermined qualities of a mixture of 97%N, 3%O may be fed under the control of a timed valve 23. The blow pipe has a cap 28 made of non-wettable material with capillary openings therein, and a wettable insert ring 55 e.g. of copper, steel, glass, which the end of the bubble contacts. The invention is stated to be applicable to the manufacture of cans, light sockets, ash trays etc.