Molten metal feeder

Abstract

In order to feed molten metal to a casting mold with precision while preventing introduction of metal oxide into a cylinder casing, an entire valve box 19 is disposed below a liquid level of the molten metal C inside a molten metal furnace D. A discharge duct 23 is upwardly open at a lower end of a valve-element moving space 24 . An inlet duct 22 is open to the valve-element moving space 24 at a position higher than the discharge duct 23 . Around an opening of the discharge duct 23 to the valve-element moving space 24 , there is formed a lower receiving seat 29 in the form of a ring. A valve element 21 includes a lower contact portion 31 which comes into annular contact with the lower receiving seat 29 in association with a lowering movement of the valve element 21 . The molten metal C inside the molten metal furnace D is introduced into a cylinder casing 4 by moving the valve element 21 to an inlet position where the lower contact portion 31 comes into the annular contact with the lower receiving seat 29 thereby to block communication between the discharge duct 23 and an inlet/outlet duct 8.

1 . A feeding apparatus for molten metal, comprising: a molten metal pump capable of introducing molten metal held in a molten metal furnace into a cylinder casing through an inlet/outlet duct by communicating the inlet-outlet duct for the molten metal with an inside of the cylinder casing and moving a piston mounted within the cylinder casing to one side and capable also of discharging the molten metal in the cylinder casing through the inlet/outlet duct by moving the piston to the other side; a feed duct for feeding the molten metal discharged through the inlet/outlet duct to a casting system; and a selector valve having a valve box defining, as openings thereof open to a valve-element moving space thereof, an inlet duct communicating with the molten metal furnace, a discharge duct communicating with the feed duct and the inlet/outlet duct and a valve element mounted therein and vertically movable between an inlet position for establishing communication between the inlet duct and the inlet/outlet duct and blocking communication between the discharge duct and the inlet/outlet duct and an outlet position for establishing communication between the discharge duct and the inlet/outlet duct and blocking communication between the inlet duct and the inlet/outlet duct, so that with an operation for moving the piston to the one side with the valve element being located at the inlet position, the molten metal in the molten metal furnace is introduced into the cylinder casing whereas with an operation for moving the piston to the other side with the valve element being located at the outlet position, the molten metal in the cylinder casing is discharged to the feed duct; 
 characterized in that    said discharge duct is upwardly open at a lower end of said valve-element moving space; said inlet duct is open to said valve-element moving space at a position higher than said discharge duct; around an opening of said discharge duct to said valve-element moving space, there is formed a lower receiving seat in the form of a ring; said valve element includes a lower contact portion which comes into annular contact with said lower receiving seat in association with a lowering movement of the valve element; and the molten metal inside the molten metal furnace is introduced into the cylinder casing by moving the valve element to the inlet position where said lower contact portion comes into the annular contact with said lower receiving seat thereby to block communication between the discharge duct and the inlet/outlet duct;    said valve box forms a cylindrical valve-element attaching hole capable of removably introducing the valve element therein; at an upper inner peripheral face of said valve-element attaching hole, a removable sleeve is fitted and fixed thereto; said inlet duct is formed at an upper portion of the valve-element moving space, said molten metal inside said cylinder casing is discharged to the feed duct by moving said valve element to an outlet position where the element comes into contact or sliding contact with said sleeve thereby to block communication between said inlet duct and said inlet/outlet duct.    
     
     
         2 . The molten metal feeding apparatus as defined in  claim 1 , characterized in that with an upward movement of said valve member, said valve member comes into engagement within said sleeve, thereby to block the communication between said inlet duct and said inlet/outlet duct.  
     
     
         3 . The molten metal feeding apparatus as defined in  claim 1 , characterized in that an upper receiving seat is formed at a lower end of said sleeve and said valve element includes an upper contact portion which comes into annular contact with said upper receiving seat in association with an upward movement of said valve element.  
     
     
         4 . A feeding apparatus for molten metal, comprising: a molten metal pump capable of introducing molten metal held in a molten metal furnace into a cylinder casing through an inlet/outlet duct by communicating the inlet-outlet duct for the molten metal with an inside of the cylinder casing and moving a piston mounted within the cylinder casing to one side and capable also of discharging the molten metal in the cylinder casing through the inlet/outlet duct by moving the piston to the other side; a feed duct for feeding the molten metal discharged through the inlet/outlet duct to a casting system; and a selector valve having a valve box defining, as openings open to a valve-element moving space thereof, an inlet duct communicating with the molten metal furnace, a discharge duct communicating with the feed duct and the inlet/outlet duct and a valve element mounted therein and vertically movable between an inlet position for establishing communication between the inlet duct and the inlet/outlet duct and blocking communication between the discharge duct and the inlet/outlet duct and an outlet position for establishing communication between the discharge duct and the inlet/outlet duct and blocking communication between the inlet duct and the inlet/outlet duct, so that with an operation for moving the piston to the one side with the valve element being located at the inlet position, the molten metal in the molten metal furnace is introduced into the cylinder casing whereas with an operation for moving the piston to the other side with the valve element being located at the outlet position, the molten metal in the cylinder casing is discharged to the feed duct; 
 characterized in that  
 said inlet duct is formed through said valve box to be open to the valve-element moving space at a position higher than said discharge duct; a base member including said cylinder casing forms an engaging portion in which a feed-duct forming member forming said feed duct is removably inserted and engaged from the above; said discharge duct is communicated with the inside of said engaging portion; said discharge duct is communicated with said feed duct with said feed-duct forming member is engaged within said engaging portion; said engaging portion defines, at a bottom thereof, a communicating duct capable of communicating with said molten metal furnace at a position lower than said discharge duct; and said feed-duct forming member integrally includes a covering member capable of closing said communicating duct in association with engagement of said feed-duct forming member within said engaging portion.  
 
     
     
         5 . The molten metal feeding apparatus as defined in  claim 4 , characterized in that said communicating duct is formed vertically along the inserting/withdrawing direction of the feed-duct forming member, and said covering member comes into engagement with the communicating duct in association with the engagement of the feed-duct forming member within the engaging portion.  
     
     
         6 . A feeding apparatus for molten metal, comprising: a molten metal pump capable of introducing molten metal held in a molten metal furnace into a cylinder casing through an inlet/outlet duct by communicating the inlet-outlet duct for the molten metal with an inside of the cylinder casing and moving a piston mounted within the cylinder casing to one side and capable also of discharging the molten metal in the cylinder casing through the inlet/outlet duct by moving the piston to the other side; a feed duct for feeding the molten metal discharged through the inlet/outlet duct to a casting system; and a selector valve having a valve box defining, as openings open to a valve-element moving space thereof, an inlet duct communicating with the molten metal furnace, a discharge duct communicating with the feed duct and the inlet/outlet duct and a valve element mounted therein and vertically movable between an inlet position for establishing communication between the inlet duct and the inlet/outlet duct and blocking communication between the discharge duct and the inlet/outlet duct and an outlet position for establishing communication between the discharge duct and the inlet/outlet duct and blocking communication between the inlet duct and the inlet/outlet duct, so that with an operation for moving the piston to the one side with the valve element being located at the inlet position, the molten metal in the molten metal furnace is introduced into the cylinder casing whereas with an operation for moving the piston to the other side with the valve element being located at the outlet position, the molten metal in the cylinder casing is discharged to the feed duct; 
 characterized in that    said inlet duct is formed through said valve box to be open to the valve-element moving space at a position higher than said discharge duct; a base member including said cylinder casing forms an engaging portion in which said valve box is removably inserted and engaged from the above; said feed duct is communicated with the inside of said engaging portion; said feed duct is communicated with said discharge duct with said valve box is engaged within said engaging portion; said engaging portion defines, at a bottom thereof, a communicating duct capable of communicating with said molten metal furnace at a position lower than said feed duct; and said valve box integrally includes a covering member capable of closing said communicating duct in association with engagement of said valve box within said engaging portion.    
     
     
         7 . The molten metal feeding apparatus as defined in  claim 6 , characterized in that said communicating duct is formed vertically along the inserting/drawing direction of said valve box; and said covering member comes into engagement with said communicating duct in association with the engagement of said valve box within said engaging portion.  
     
     
         8 . A feeding apparatus for molten metal, comprises: a molten metal pump capable Of introducing molten metal held in a molten metal furnace into a cylinder casing through an inlet/outlet duct by communicating the inlet-outlet duct for the molten metal with an inside of the cylinder casing and moving a piston mounted within the cylinder casing to one side and capable also of discharging the molten metal in the cylinder casing through the inlet/outlet duct by moving the piston to the other side; a feed duct for feeding the molten metal discharged through the inlet/outlet duct to a casting system; and a selector valve having a valve box defining, as openings open to a valve-element moving space thereof, an inlet duct communicating with the molten metal furnace, a discharge duct communicating with the feed duct and the inlet/outlet duct and a valve element mounted therein and vertically movable between an inlet position for establishing communication between the inlet duct and the inlet/outlet duct and blocking communication between the discharge duct and the inlet/outlet duct and an outlet position for establishing communication between the discharge duct and the inlet/outlet duct and blocking communication between the inlet duct and the inlet/outlet duct, so that with an operation for moving the piston to the one side with the valve element being located at the inlet position, the molten metal in the molten metal furnace is introduced into the cylinder casing whereas with an operation for moving the piston to the other side with the valve element being located at the outlet position, the molten metal in the cylinder casing is discharged to the feed duct; 
 characterized in that    said molten metal pump includes a cylinder-chamber forming hole formed in said cylinder casing, a piston vertically movable within said cylinder-chamber forming hole, and an operating rod for vertically moving said piston; and said operating rod includes, upwardly of said piston, a scraper for closing a gap between said operating rod and said cylinder-chamber forming hole and slidable along substantially entire periphery relative to said cylinder-chamber forming hole in association with the vertical moving operation of said operating rod.    
     
     
         9 . A feeding apparatus for molten metal, comprises: a molten metal pump capable of introducing molten metal held in a molten metal furnace into a cylinder casing through an inlet/outlet duct by communicating the inlet-outlet duct for the molten metal with an inside of the cylinder casing and moving a piston mounted within the cylinder casing to one side and capable also of discharging the molten metal in the cylinder casing through the inlet/outlet duct by moving the piston to the other side; a feed duct for feeding the molten metal discharged through the inlet/outlet duct to a casting system; and a selector valve having a valve box defining, as openings open to a valve-element moving space thereof, an inlet duct communicating with the molten metal furnace, a discharge duct communicating with the feed duct and the inlet/outlet duct and a valve element mounted therein and vertically movable between an inlet position for establishing communication between the inlet duct and the inlet/outlet duct and blocking communication between the discharge duct and the inlet/outlet duct and an outlet position for establishing communication between the discharge duct and the inlet/outlet duct and blocking communication between the inlet duct and the inlet/outlet duct, so that with an operation for moving the piston to the one side with the valve element being located at the inlet position, the molten metal in the molten metal furnace is introduced into the cylinder casing whereas with an operation for moving the piston to the other side with the valve element being located at the outlet position, the molten metal in the cylinder casing is discharged to the feed duct; 
 characterized in that  
 said valve box includes an insertion hole having an upper end open to the molten metal in the molten metal furnace; said selector valve includes an operating rod capable of vertically moving operation; said valve element includes a valve-element portion disposed to come into sliding contact with an inner peripheral face of said insertion hole; in association with a vertical movement of said valve element within said insertion hole by said operating rod, the duct for the molten metal can be switched over between an inlet position for establishing communication between said inlet duct and said inlet/outlet duct and blocking communication between said discharge duct and said inlet/outlet duct by means of said valve-element portion and an outlet position for establishing communication between said discharge duct and said inlet/outlet duct and blocking communication between said discharge duct and said insertion hole by means of said valve-element portion and blocking also communication between said inlet duct and said inlet/outlet duct by means of said valve-element portion; and  
 the operating rod includes, upwardly of said valve-element portion, a scraper for closing a gap between this operating rod and said insertion hole and slidable along substantially entire periphery relative to the inner peripheral face of the insertion hole in association with the vertical moving operation of said operating rod.  
 
     
     
         10 . The molten metal feeding apparatus as defined in  claim 9 , characterized in that said insertion hole comprises an upper large-diameter insertion hole and a lower small-diameter insertion hole connected together, the valve element includes a pair of upper and lower valve-element portions provided to come into sliding contact with an inner peripheral face of the small-diameter insertion hole, and with a vertical movement of the valve element within the insertion hole by the operating rod, the duct for the molten metal is switched over between an inlet position for establishing communication between the inlet duct and the inlet/outlet duct and blocking communication between the discharge duct and the inlet/outlet duct by means of the lower valve-element portion and an outlet position for establishing communication between the discharge duct and the inlet/outlet duct and blocking communication between the discharge duct and the insertion hole by means of the upper valve-element portion and blocking also communication between the inlet duct and the inlet/outlet duct by means of the lower valve-element portion.  
     
     
         11 . The molten metal feeding apparatus as defined in any one of claims  8 - 10 , characterized in that when the operating rod has moved to the upper end of its movable range, said scraper is moved to the vicinity of the upper end of the insertion hole.  
     
     
         12 . The molten metal feeding apparatus as defined in any one of claims  8 - 10 , characterized in that said scraper is formed by non-withdrawably fitting, along the outer periphery of said operating rod, a ceramic ring member formed like letter C by cutting a peripheral portion thereof and then engaging this ring member within said insertion hole with elastic radially inward deformation of this ring member.