Gas mixing and dispersement in pumps for pumping molten metal

A pump for mixing gas and pumping molten metal, comprising:

• a base adapted to be submerged in a bath of the molten metal, said base comprising
• an inlet and an outlet,
• a mixing impeller chamber adapted to mix gas and molten metal,
• a pumping impeller chamber adapted to pump molten metal, said mixing chamber and said pumping chamber being stacked over each other, and
• said inlet and said outlet being in fluid communication with at least one of said mixing chamber and said pumping chamber;
• a shaft adapted to be rotatably driven extending into said mixing chamber and said pumping chamber;
• a first impeller member supported on said shaft and adapted to rotate in said mixing chamber effective to cause molten metal to flow into said base along a molten metal inlet direction;
• a second impeller member supported on said shaft and adapted to rotate in said pumping chamber;
• a source of gas;
• and
• a gas conduit extending from said gas source adapted to direct said gas along said molten metal inlet direction into said mixing chamber.

A pump for dispersing gas and mixing gas and molten metal, comprising:

• a base adapted to be submerged in a bath of the molten metal comprising
• an inlet and an outlet,
• a mixing impeller chamber adapted to mix gas and molten metal,
• a pumping impeller chamber adapted to pump molten metal, and
• said inlet and said outlet being in fluid communication with at least one of said mixing chamber and said pumping chamber;
• a shaft adapted to be rotatably driven;
• a first impeller member supported on said shaft adapted to rotate in said mixing chamber;
• a second impeller member supported on said shaft adapted to rotate in said pumping chamber;
• a source of gas;
• and
• a gas passageway extending from said gas source and including an outlet located near said mixing impeller chamber;
• and
• a gas dispersement member composed of porous refractory material adapted to disperse gas from said gas passageway.

A pump for dispersing gas and pumping molten metal, comprising:

• a base adapted to be submerged in a bath of the molten metal comprising
• an inlet and an outlet,
• a mixing impeller chamber adapted to mix gas and molten metal,
• a pumping impeller chamber adapted to pump molten metal, and
• said inlet and said outlet being in fluid communication with at least one of said mixing chamber and said pumping chamber;
• a shaft adapted to be rotatably driven;
• an impeller supported on said shaft adapted to rotate in either one or both of said mixing chamber and said pumping chamber;
• a source of gas;
• and
• a gas passageway extending from said gas source and including an outlet that directs gas into said mixing impeller chamber;
• and
• a gas dispersement member at said outlet of said gas passageway composed of porous refractory material adapted to disperse gas into small bubbles that are directed into said mixing impeller chamber.