Method and apparatus for pumping liquid metal alloys

Abstract

This invention provides an improved method and apparatus for controlling the flow of molten metal alloys and, in particular, to a method to finely control the delivery rate of liquid aluminum alloys and the liquid fraction of semi-solid aluminum alloys. The apparatus and method described herein provide for the pumping of liquid metal alloys in a precise and controlled manner. By controlling the heat flow through a section of the pump piston, the pump chamber, the porous liner of the pump chamber and the metal alloy charge, the present invention provides a means to deliver liquid metal alloys at high pressure through one or more exit ports.

What is claimed is: 
     
         1 . A method to deliver a liquid metal alloy charge in controlled amounts through one or more ports by creating a pressure tight seal between the walls of a piston chamber and a movable piston, the pressure tight seal being composed of a solid annulus of the metal alloy charge. 
     
     
         2 . The method of  claim 1  wherein the solid annulus is maintained using a cooling channel in thermal contact with a section of the movable piston. 
     
     
         3 . The method of  claim 1  wherein the movable piston is used to pressurize the liquid or semi-solid metal alloy charge to facilitate the delivery of the charge to a port or a group of ports. 
     
     
         4 . An apparatus to deliver a liquid metal alloy charge in controlled amounts through one or more ports by creating a pressure tight seal between the walls of a piston chamber and a movable piston, the pressure tight seal being composed of a solid annulus of the metal alloy charge. 
     
     
         5 . The apparatus of  claim 4  wherein the solid annulus is maintained by a cooling channel in thermal contact with a section of the movable piston. 
     
     
         6 . The apparatus of  claim 4  wherein the movable piston is used to pressurize the liquid or semi-solid metal alloy charge to facilitate the delivery of the charge to a port or a group of ports. 
     
     
         7 . A method to deliver a liquid fraction of an metal alloy charge in controlled amounts through one or more ports by creating a pressure tight seal between the porous liner of a piston chamber and a movable piston, the pressure tight seal being composed of a solid annulus of the metal alloy charge. 
     
     
         8 . The method of  claim 7  wherein the solid annulus is maintained by a cooling channel in thermal contact with a section of the movable piston. 
     
     
         9 . The method of  claim 7  wherein the movable piston is used to pressurize the liquid or semi-solid metal alloy charge to facilitate the delivery of the liquid fraction of a charge to a port or a group of ports. 
     
     
         10 . An apparatus to deliver a liquid fraction of an metal alloy charge in controlled amounts through one or more ports by creating a pressure tight seal between the porous liner of a piston chamber and a movable piston, the pressure tight seal composed of a solid annulus of the metal alloy charge. 
     
     
         11 . The apparatus of  claim 10  wherein the solid annulus is maintained by a cooling channel in thermal contact with a section of the movable piston. 
     
     
         12 . The apparatus of  claim 10  wherein the movable piston is used to pressurize the liquid or semi-solid metal alloy charge to facilitate the delivery of the liquid fraction of a charge to a port or a group of ports.