METHOD OF REGULATING THE PRESSURE IN LOW-PRESSURE CASTING PLANTS

• US 3,844,331 A
• Filed: 06/08/1973
• Issued: 10/29/1974
• Est. Priority Date: 06/22/1972
• Status: Expired due to Term

• Current Assignee: Alphonse Benjamin Py, Jean-Claude Pichouron, Jean Henri Lefebvre
• Original Assignee: Alphonse Benjamin Py, Jean-Claude Pichouron, Jean Henri Lefebvre
• Inventors: Py, Alphonse Benjamin, Lefebvre, Jean Henri, Pichouron, Jean-Claude
• Primary Examiner(s): Overholser, J. Spencer
• Assistant Examiner(s): Roethel, John E.
• Application Number:
  US05/368,341
• Time in Patent Office: 508 Days
• Field of Search: 164/119,155,306,309
• US Class Current: 164/457
• CPC Class Codes: B22D 18/08 Controlling, supervising, e.g. for safety reasons controlling or regulating in general G05

Abstract

Method of regulating the pressure in a low-pressure casting plant, wherein in a first step the furnace is supplied with two gas inputs, one of these two inputs being discontinued when the metal engages a first control means, the pressure in said furnace being memorized when the metal engages a second control means, and in a second step gas is supplied to the furnace until the mould is properly filled, whereafter the previously memorized pressure is utilized for supplying both gas inputs to the furnace; in a third step the memorized pressure is utilized for discontinuing one of the two inputs and regulating the pressure in said furnace during the setting of the metal in the mold.

Claims

1. In a method of regulating the pressure in a low-pressure casting plant comprising a heated furnace containing molten metal solid at room temperature and a gaseous space overlying the molten metal, a mould disposed externally and above said furnace, a dipper pipe connecting the furnace bottom to the mould bottom, first control means located between said furnace and the mould bottom, second control means disposed in the bottom of said mould, and third control means disposed in the upper portion of said mould, the furnace is supplied in a first step with two separate gas inputs, one of these two inputs being discontinued when the metal engages said first control means while memorizing the pressure in said furnace when the metal engages said second control means;

in a second step gas is supplied to said furnace until the mould is properly filled, the memorized pressure being then utilized for delivering the two gas inputs to the furnace, and in a third step the memorized pressure is utilized for discontinuing at least one of said two inputs and regulating the pressure in the furnace during the solidification of the metal in said mould.

2. In the method as set forth in claim 1, one of the two gas inputs which is discontinued is greater than the other, non-discontinued input.

3. In the method as set forth in claim 1, said two gas inputs are monitored from a source of gas under pressure.

4. In the method as set forth in claim 2, the monitoring pressure of the larger of the two inputs is eliminated when the metal engages the first control means.

5. In the method as set forth in claim 4, the memorized pressure is converted into a pressure for controlling and monitoring safety distributors.

6. In the method as set forth in claim 5, the gas outputs are responsive to the discrepancy existing between the gaseous pressure in the furnace and the memorized pressure.