Pump for pumping molten metal with expanded piston

A pump for pumping molten metal comprising:

• a pump base comprised of non-metallic, heat resistant material, said pump base comprising an inlet opening, a wall forming a pumping chamber, a passageway that communicates said inlet opening with said pumping chamber, and an outlet opening that communicates with said pumping chamber;
• a piston made of non-metallic, heat resistant material disposed in said pumping chamber:
• a connecting member fastened to said piston;
• a valve that permits and restricts flow of molten metal in said pump base;
• and
• an actuator connected to said connecting member, said actuator being adapted for effecting reciprocal movement of said piston in said pumping chamber;
• wherein said piston has a coefficient of thermal expansion and configuration effective to enable said piston to expand into contact with said wall during said reciprocal movement of said piston in said pumping chamber,
• further comprising a gasket comprising non-metallic, heat-resistant material disposed in said pumping chamber.

A pump for pumping molten metal comprising:

• a pump base comprised of non-metallic, heat resistant material, said pump base comprising an inlet opening, a wall forming a pumping chamber, a passageway that communicates said inlet opening with said pumping chamber, and an outlet opening that communicates with said pumping chamber;
• a piston made of non-metallic, heat resistant material disposed in said pumping chamber;
• a connecting member fastened to said piston;
• a valve that permits and restricts flow of molten metal in said pump base;
• and
• an actuator connected to said connecting member, said actuator being adapted for effecting reciprocal movement of said piston in said pumping chamber;
• wherein said piston has a coefficient of thermal expansion and configuration effective to enable said piston to expand into contact with said wall during said reciprocal movement of said piston in said pumping chamber;
• wherein said wall comprises an upper annular sleeve comprising non-metallic, heat-resistant material disposed along a path of travel of an upper surface of said piston and a lower annular sleeve made of non-metallic, heat resistant material disposed below said upper sleeve in said pumping chamber, and wherein a gasket comprised of non-metallic, heat-resistant material is disposed between said upper sleeve and said lower sleeve.

An apparatus for die casting molten metal comprising:

• a pump for pumping molten metal comprising:
• a pump base comprised of non-metallic, heat resistant material, said pump base comprising an inlet opening, a wall forming a pumping chamber, a passageway that communicates said inlet opening with said pumping chamber, and an outlet opening that communicates with said pumping chamber;
• a piston made of non-metallic, heat resistant material disposed in said pumping chamber;
• a connecting member fastened to said piston;
• a valve that permits and restricts flow of molten metal in said pump base;
• and
• an actuator connected to said connecting member adapted to effect reciprocal movement of said piston in said pumping chamber;
• wherein said connecting member has a coefficient of thermal expansion and configuration relative to said piston effective to enable said connecting member to expand said piston into contact with said wall;
• a conduit extending from said outlet opening to a discharge location outside said base;
• a shot chamber that receives molten metal pumped from said conduit at the discharge location;
• and
• a ram disposed in said shot chamber and adapted to direct molten metal in said shot chamber to a die for casting said molten metal.

A pump for pumping molten metal comprising:

• a pump base comprised of non-metallic, heat resistant material, said pump base comprising an inlet opening, a pumping chamber, a passageway that communicates said inlet opening with said pumping chamber, and an outlet opening that communicates with said pumping chamber;
• a piston comprising non-metallic, heat-resistant material disposed in said pumping chamber, said piston comprising an opening in an upper surface thereof;
• a sleeve comprising non-metallic, heat-resistant material disposed in said pumping chamber around said piston;
• a metal connecting member disposed in the opening in said piston and connected to said piston;
• a valve that permits and restricts flow of molten metal in said pump base;
• and
• at least one actuator connected to said connecting member adapted for effecting reciprocal movement of said piston in said pumping chamber;
• wherein said connecting member and said piston have relative coefficients of thermal expansion and configurations effective to enable said connecting member to expand said piston into contact with said sleeve during said reciprocal movement of said piston in said pumping chamber.

An apparatus for die casting molten metal comprising:

• a pump for pumping molten metal comprising:
• a pump base comprised of non-metallic, heat resistant material, said pump base comprising an inlet opening, a wall forming a pumping chamber, a passageway that communicates said inlet opening with said pumping chamber, and an outlet opening that communicates with said pumping chamber;
• a piston made of non-metallic, heat resistant material disposed in said pumping chamber;
• a connecting member fastened to said piston;
• a valve that permits and restricts flow of molten metal in said pump base;
• an actuator connected to said connecting member adapted to effect reciprocal movement of said piston in said pumping chamber;
• and
• a gasket comprising non-metallic, heat-resistant material disposed in said pumping chamber;
• wherein said piston has a coefficient of thermal expansion and configuration effective to enable said piston to expand into contact with said wall during said reciprocal movement of said piston in said pumping chamber;
• a conduit extending from said outlet opening to a discharge location outside said base;
• a shot chamber that receives molten metal pumped from said conduit at the discharge location;
• and
• a ram disposed in said shot chamber and adapted to direct molten metal in said shot chamber to a die for casting said molten metal.