Negative pressure updraught pouring device and method

Abstract

A negative pressure updraught pouring device and method are provided. A melting furnace has a top end covered by a flat plate with a suction pipe that has a bottom end dipped into the molten steel in the melting furnace. A mold is placed on the flat plate and the mold's flow path system is connected with the suction pipe. A chamber is covered on the mold and the flat plate, and the air inside the chamber is drawn out to reduce the air pressure inside the chamber and the mold cavity. When the mold cavity is filled with molten steel, a driving assembly is used to move a blocker to substantially block the flow of the molten steel in the flow path system. The negative air pressure is relieved to flow the molten steel inside the flow path system back into the melting furnace.

1 . A negative pressure updraught pouring device provided for a plurality of molds to form a plurality of casts, where each mold has a mold cavity, a flow path system, and an air passage, the mold cavity and the flow path system are connected with each other inside the mold while the air passage is connected with the mold cavity, and each mold is a sand mold and its air passage on the mold is a gap between sand grains of the sand mold; a flat plate having a suction pipe is covered onto a top end of a melting furnace; the mold is placed on the flat plate, and the flow path system of the mold is connected with a top end of the suction pipe; a chamber is connected with an extraction device and is placed over the mold and the flat plate to draw the air inside the chamber out; the negative pressure updraught pouring device is characterized in that:
 a blocker is provided within the mold, where the blocker has one end provided with a driving assembly for driving the blocker so as to move another end of the blocker to block substantially the flow path system in the mold.   
     
     
         2 . The negative pressure updraught pouring device as claimed in  claim 1 , wherein the flow path system includes a main flow path and at least one in-flow path, the main flow path is connected with the top end of the suction pipe, while the at least one in-flow path is located between the main path and the mold cavity; the another end of the blocker is connected into the at least one in-flow path. 
     
     
         3 . The negative pressure updraught pouring device as claimed in  claim 2 , wherein the mold is provided with a connecting tube therein, the connecting tube is axially connected into the main flow path, and the connecting tube has a top end in communication with the in-flow path and has a bottom end in communication with the top end of the suction pipe. 
     
     
         4 . The negative pressure updraught pouring device as claimed in  claim 1 , wherein the mold includes a upper die and a lower die, the upper die has a bottom surface provided with a bowl-shaped recess, the bowl-shaped recess has a top end from which a vertical hole is extended upwardly, and the vertical hole is upwardly in communication with a space outside the upper die; the another end of the blocker is provided with a bowl-shaped portion with an opening that faces downwardly, for being positioned into the bowl-shaped recess; and the driving assembly includes a pushing rod and a driving element that are moved in a linkage way, and the pushing rod has one end located within the vertical hole for pushing the blocker to be moved downwardly. 
     
     
         5 . The negative pressure updraught pouring device as claimed in  claim 4 , wherein one end of the pushing rod is in a separate and disconnecting state with the blocker. 
     
     
         6 . The negative pressure updraught pouring device as claimed in  claim 5 , wherein one end of the blocker is a standing pillar for positioned within the vertical hold. 
     
     
         7 . The negative pressure updraught pouring device as claimed in  claim 4 , wherein one end of the blocker is a standing pillar for positioned within the vertical hold. 
     
     
         8 . The negative pressure updraught pouring device as claimed in  claim 1 , further comprising at least two pressing-plate assemblies, where each pressing-plate assembly includes a pressing plate and a pushing element, the pressing plate is located within the chamber, and the pushing element has one end connected with the pressing plate, so as to move the pressing plate downwardly to be positioned. 
     
     
         9 . A method using the negative pressure updraught pouring device as claimed in  claim 1 , comprising steps of:
 a. covering the top end of the melting furnace with the flat plate having the suction pipe, filling the melting furnace with molten steel, and dipping a bottom end of the suction pipe into the molten steel;   b. placing the mold on the flat plate to connect the flow path system of the mold with the top end of the suction pipe, and placing the chamber over the mold and the flat plate, drawing the air inside the chamber out to reduce the air pressure inside the chamber and the mold cavity, so as to suck the molten steel inside the melting furnace upwardly through the suction pipe to flow the molten steel into the mold cavity;   c. when the mold cavity is filled with the molten steel, using the driving assembly to drive the blocker, so as to move the another end of the blocker to block substantially the flow path system in the mold; then relieving the negative air pressure inside the chamber to flow the molten steel inside the flow path system back into the melting furnace;   d. removing the chamber and the driving assembly, and moving the mold and the blocker, while keeping the flat plate unmoved to cover the top end of the melting furnace; and   e. repeating the steps b to d until the treatment of the plurality of molds is completed.   
     
     
         10 . The method as claimed in  claim 9 , wherein in step b, when the chamber is placed over the mold and the flat plate, using at least one pushing element to push at least one pressing plate, so as to move the at least one pressing plate downwardly to be pressed against the mold's top surface to have the mold positioned.