Ball check valve molten metal injector

Abstract

The injector includes a cylinder defining a piston cavity housing a reciprocating piston for pumping molten metal from a holder furnace and injecting the molten metal into the mold cavity of a casting mold. The piston defines a molten metal intake for receiving molten metal into the piston cavity. A check valve is positioned in the molten metal intake defmed by the piston. The check valve is preferably a ball check valve. The cylinder further defines a fill conduit in fluid communication with the piston cavity. The fill conduit extends through a top wall of the cylinder and extends along an axis substantially parallel to the piston.

What is claimed is:  
     
         1 . An injector for injecting molten metal into a mold cavity of a casting mold, comprising: 
 a cylinder for at least partially submerging in a supply of molten metal, with the cylinder defining a piston cavity, and with the cylinder defining a fill conduit in fluid communication with the piston cavity and extending through a top wall of the cylinder;    a piston positioned within the piston cavity and movable through a downstroke and a return stroke, with the piston defining a molten metal intake for receiving molten metal into the piston cavity; and    a lifting mechanism fixed to the cylinder and operatively connected to the piston for moving the piston through the downstroke and the return stroke, 
 wherein the fill conduit extends along an axis substantially parallel to the piston.  
   
     
     
         2 . The injector of  claim 1 , further including a check valve positioned in the molten metal intake defined by the piston, with the check valve having an inlet for receiving molten metal into the piston cavity when the cylinder and piston are at least partially submerged in molten metal.  
     
     
         3 . The injector of  claim 2 , wherein the check valve is a ball check valve.  
     
     
         4 . The injector of  claim 2 , wherein the check valve is configured to permit inflow of molten metal into the piston cavity during the downstroke of the piston when the cylinder and piston are at least partially submerged in molten metal, and wherein the check valve is configured to prevent inflow of molten metal into the piston cavity during the return stroke of the piston when the cylinder and piston are at least partially submerged in molten metal.  
     
     
         5 . The injector of  claim 2 , further including a molten metal filter covering the inlet to the check valve.  
     
     
         6 . The injector of  claim 1 , wherein the piston and the cylinder are made of materials compatible with molten aluminum and molten aluminum alloys.  
     
     
         7 . The injector of  claim 1 , wherein the lifting mechanism is a rack and pinion.