Apparatus that automatically controls the correlation between time and airpressure

Claim 1

IN AN APPARATUS FOR CONTROLLING A CASTING PROCESS IN WHICH A MOLTEN METAL BODY IS RAISED FROM A VESSEL INTO A MOLD BY APPLICATION OF A PRESSURIZED MEDIUM TO THE SURFACE OF THE MOLTEN METAL IN THE VESSEL, A PNEUMATIC CIRCUIT FOR APPLYING PRESSURE TO SAID VESSEL AND FOR RAIS ING SAID MOLTEN METAL INTO SAID MOLD, PROGRAMMING MEANS INCLUDING A TIME-PRESSURE CURVE FOLLOWING MEANS ADAPTED TO TRACE A PREDETERMINED TIME-PRESSURE CURVE, POTENTIOMETER MEANS CONNECTED TO RESPOND TO SAID TIMEPRESSURE CURVE FOLLOWING MEANS FOR DEVELOPING AN OUTPUT SIGNAL IN PROPORTION TO SAID CURVE, FIRST VALVE MEANS DISPOSED IN SAID PNEUMATIC CIRCUIT AND BEING RESPONSIVE TO SAID OUTPUT SIGNAL FOR OPENING SAID PNEUMATIC CIRCUIT IN RESPONSE THERETO AND PERMITTING SAID PRESSURIZED MEDIUM TO ENTER SAID VESSEL IN ACCORDANCE WITH SAID TIMEPRESSURE CURVE, PRESSURE RESPONSIVE MEANS FOR SENSING THE PRESSURE IN SAID VESSEL UPON SAID MOLTEN METAL BODY AND ACTUATING A TIMING MEANS UPON SAID PRESSURE REACHING A PREDETERMINED MAGNITUDE, MEANS SUPPLYING A CONSTANT PRESSURE TO SAID VESSEL DURING A PERIOD SAID TIMING MEANS IS IN OPERATION, AND RELIEF VALVE MEANS DISPOSED IN SAID PNEUMATIC CIRCUIT FOR RELEASING PRESSURE FROM SAID VESSEL AFTER LAPSE OF SAID PERIOD.