JPS5756139A - Molding device - Google Patents

Abstract

PURPOSE:To prevent leakage of the mixed gas of fuel gas and gaseous oxygen to be used for generating blast, by installing a blast generating device separately and communicating the blast generating device to a molding device through a communicating pipe and a valve, in the molding device which presses together the molding sand utilizing the pressure of a blast. CONSTITUTION:A pattern section 3 having a pattern 5 is placed on a table 1 with an opening 2, and a molding flask 7 is put on the table 1, and then, molding sand S is charged on the pattern section 3. Thin holes 4 are installed to the pattern section 3 where the molding sand is not packed well, so that the holes reach the opening 2, and bent plugs are fitted to the top of the holes. A covering member 8 is firmly fitted to the upper end of the molding flask 7 through a sealing member 9, and a communicating pipe 12 from a blast generating vessel 14 is connected to the top of the covering member 8 through an opening and closing valve 13. A fuel gas 24 and gaseous oxygen 25 are introduced into a closed vessel 14, and the gases are blasted with an igniter 16. The molding sand S is pressed together by introducing the high- pressure blast to the surface of the molding sand S in a molding device by opening the valve 13 immediately after the gases are exploded. After pressing, the blast is discharged into the atmosphere through the thin holes 4. Since the fuel-mixed gas is not supplied directly to the space above the molding sand in the molding device, the gas does not leak through the thin holes 4.