Thermally efficient, cover for metal containment vessel, related system and methods

Abstract

A thermally efficient cover for the molten metal held in a furnace, tundish, ladle, crucible or other containment vessel. Through substantially horizontal movement, this cover allows for periodic removal, particularly by retraction, for accessing contents of that furnace from a top aperture in the containment vessel. This invention further relates to a covered furnace system and methods of use.

1 . A cover for a molten metal container, said container having an access point for molten metal to be periodically extracted therefrom, said cover comprising:
 a. a mechanical support for positioning at or near the access point on the container;   b. a cover that is capable of reducing heat loss from the molten metal in the container through its access point; and   c. means for moving the cover with the mechanical support for temporary positioning over the access point of the container.   
   
   
       2 . The molten metal container cover of  claim 1 , which further comprises:
 means for cycling movement of the cover back and forth, over the access point, for a predetermined length of time to reduce molten metal heat loss through the access point.   
   
   
       3 . The molten metal container cover of  claim 1  that extends and retracts from the mechanical support to coordinate with metal extraction from the container. 
   
   
       4 . The molten metal container cover of  claim 3 , wherein the cover extension and retraction is performed mechanically. 
   
   
       5 . The molten metal container cover of  claim 1 , wherein the cover comprises a radiation shield. 
   
   
       6 . The molten metal container cover of  claim 1 , wherein the cover is made of a lightweight material. 
   
   
       7 . The molten metal container cover of  claim 1 , wherein the cover is made of a flexible material. 
   
   
       8 . The molten metal container cover of  claim 1 , wherein the cover has low mechanical inertia. 
   
   
       9 . The molten metal container cover of  claim 1 , wherein the cover is capable of folding onto itself. 
   
   
       10 . The molten metal container cover of  claim 1 , wherein the cover consists essentially of a ceramic fiber cloth. 
   
   
       11 . The molten metal container cover of  claim 1 , wherein the mechanical support includes one or more rolls about which the cover is wound and unwound. 
   
   
       12 . The molten metal container cover of  claim 1 , wherein the cover moves substantially parallel to the access point in the container. 
   
   
       13 . The molten metal container cover of  claim 12 , wherein the access point is a top aperture in the container and the cover moves back and forth over the top aperture in a substantially horizontal direction. 
   
   
       14 . The molten metal container cover of  claim 13 , wherein the cover extension and retraction includes reciprocating movement from at least one roll. 
   
   
       15 . The molten metal container cover of  claim 14 , wherein the cover is adapted for extending and retracting between a pair of rolls immediately adjacent the top aperture. 
   
   
       16 . The molten metal container cover of  claim 13 , wherein the roll is spring-loaded. 
   
   
       17 . The molten metal container cover of  claim 16 , wherein the spring-loaded roll includes at least one of: an air actuator, an electrical solenoid and a hydraulic actuator. 
   
   
       18 . The molten metal container cover of  claim 16 , wherein the spring-loaded roll includes a traction motor. 
   
   
       19 . The molten metal container cover of  claim 13 , wherein the roll is loaded by a rack and pinion system. 
   
   
       20 . The molten metal container cover of  claim 1 , wherein the metal is non-ferrous. 
   
   
       21 . The molten metal container cover of  claim 20 , wherein the non-ferrous metal is an aluminum alloy. 
   
   
       22 . The molten metal container cover of  claim 1 , wherein the cover is programmed to extend and retract on a timed cycle selected from the group consisting of: more than 10×/minute; 5 to 10×/minute; 2 to 4×/minute; less than 2×/minute; and 1× or more per hour. 
   
   
       23 . A system for melting and solidifying molten metal with less radiant heat loss, said system comprising:
 a plural-walled metal containment assembly having at least one aperture for periodically accessing and extracting the molten metal from the containment assembly,   at least one immersion heating element, and   a retractable cover for positioning over the aperture and moving in a substantially lateral manner relative to the aperture for allowing periodic access into the containment assembly for the extraction of molten metal therefrom.   
   
   
       24 . The molten metal system of  claim 23 , which further comprises:
 means for cycling movement of the retractable cover back and forth, over the aperture, for a predetermined length of time to reduce molten metal heat loss through the aperture.   
   
   
       25 . The molten metal system of  claim 23 , wherein the cover retraction is performed mechanically. 
   
   
       26 . The molten metal system of  claim 23 , wherein the retractable cover is made of a lightweight material. 
   
   
       27 . The molten metal system of  claim 23 , wherein the retractable cover is made of a flexible material. 
   
   
       28 . The molten metal system of  claim 23 , wherein the retractable cover has low mechanical inertia. 
   
   
       29 . The molten metal system of  claim 23 , wherein the retractable cover is capable of folding onto itself 
   
   
       30 . The molten metal system of  claim 23 , wherein the retractable cover consists essentially of a ceramic fiber cloth. 
   
   
       31 . The molten metal system of  claim 23 , wherein the retractable cover moves back and forth over the aperture in a substantially horizontal direction. 
   
   
       32 . The molten metal system of  claim 23 , wherein the molten metal is non-ferrous. 
   
   
       33 . The molten metal system of  claim 23 , which further comprises a mechanical support for the retractable cover, said mechanical support including one or more rolls about which the retractable cover is wound and unwound. 
   
   
       34 . The molten metal system of  claim 33 , wherein the retractable cover retracts with reciprocal movement from a pair of rolls located adjacent the containment aperture. 
   
   
       35 . The molten metal system of  claim 33 , wherein the roll is spring-loaded. 
   
   
       36 . The molten metal system of  claim 35 , wherein the spring-loaded roll includes at least one member of the group consisting of: an air actuator; an electrical solenoid; a hydraulic actuator and a traction motor. 
   
   
       37 . The molten metal system of  claim 33 , wherein the roll is loaded by a rack and pinion system. 
   
   
       38 . The molten metal system of  claim 23 , wherein the cover is programmed to retract repeatedly on a timed cycle selected from the group consisting of: more than 10×/minute; 5 to 10×/minute; 2 to 4×/minute; less than 2×/minute; and 1× or more per hour. 
   
   
       39 . The molten metal system of  claim 23 , wherein the containment assembly is portable. 
   
   
       40 . A method for holding molten metal in a heated container assembly with less radiant heat loss through an aperture in the assembly, said method comprising the steps of:
 providing the assembly with a retractable cover over the aperture; and   programming movement of the cover over the aperture for a preset time interval.   
   
   
       41 . The molten metal holding method of  claim 40 , wherein retraction of the cover is performed substantially mechanically. 
   
   
       42 . The molten metal holding method of  claim 40 , wherein the retractable cover is made of a lightweight material with low mechanical inertia. 
   
   
       43 . The molten metal holding method of  claim 40 , wherein the retractable cover is made of a flexible material that is capable of folding onto itself. 
   
   
       44 . The molten metal holding method of  claim 40 , wherein the retractable cover consists essentially of a ceramic fiber cloth. 
   
   
       45 . The molten metal holding method of  claim 40 , wherein the retractable cover moves back and forth over the aperture in a substantially horizontal direction. 
   
   
       46 . The molten metal holding method of  claim 40 , wherein the assembly further comprises a mechanical support for the retractable cover, said mechanical support including one or more elongate rolls about which the retractable cover is wound and unwound. 
   
   
       47 . The molten metal holding method of  claim 45 , wherein the retractable cover retracts with reciprocal movement from a pair of rolls located adjacent the aperture. 
   
   
       48 . The molten metal holding method of  claim 45 , wherein the roll is spring-loaded and includes at least one member of the group consisting of: an air actuator; an electrical solenoid; a hydraulic actuator and a traction motor. 
   
   
       49 . The molten metal holding method of  claim 45 , wherein the roll is loaded with a rack and pinion system. 
   
   
       50 . The molten metal holding method of  claim 39 , wherein the cover is programmed to retract repeatedly on a timed cycle selected from the group consisting of: more than 10×/minute; 5 to 10×/minute; 2 to 4×/minute; less than 2×/minute; and 1× or more per hour.