Method and apparatus for casting

Abstract

A method and apparatus for producing a cast product. The apparatus includes a mould ( 10 ) having a mould cavity ( 12 ) and a runner ( 14 ) which communicates with the mould cavity ( 12 ), The mould ( 10 ) is connected to a feed pipe ( 11 ) for feeding molten material to the mould cavity ( 12 ) through the runner ( 14 ). The mould ( 10 ) includes a valve ( 20 ) for closing the runner ( 14 ) to material flow upon receipt within the mould cavity ( 12 ) of sufficient molten material. The method includes closing the runner ( 14 ) by the valve ( 20 ) upon receipt of sufficient molten material within the cavity ( 12 ) and thereafter disconnecting the feed pipe ( 11 ) from the mould ( 10 ) and inverting mould ( 10 ). The method further includes relatively displacing the mould ( 10 ) and the feed pipe ( 11 ) for connection of the feed pipe ( 11 ) to a further mould and allowing the molten material to solidify within the mould cavity ( 12 ) prior to removal therefrom.

1 . A method of producing a cast product, said method employing a mould having a mould cavity and a runner which communicates with the mould cavity, said mould being connected to a feed pipe for feeding molten material to said mould cavity through said runner, said mould including a valve arrangement for closing said runner to material flow upon receipt within said mould cavity of sufficient molten material, said method including closing said runner by said valve arrangement upon receipt of said sufficient molten material within said cavity and thereafter disconnecting said feed pipe from said mould and inverting said mould, and further including relatively displacing said mould and said feed pipe for connection of said feed pipe to a further mould and allowing said molten material to solidify within said mould cavity prior to removal therefrom.  
   
   
       2 . A method according to  claim 1 , said mould including a feed reservoir in communication with said mould cavity said method involving feeding molten material to said feed reservoir before closing said runner by said valve arrangement and said molten material in said feed reservoir feeding said mould cavity upon inversion of said mould as said molten material in said mould cavity solidifies.  
   
   
       3 . A method according to  claim 2 , wherein said feed reservoir is positioned above said mould cavity when said mould is inverted.  
   
   
       4 . A method according to  claim 3 , said molten material of said feed reservoir feeding said mould cavity under gravity.  
   
   
       5 . A method according to  claim 2 , said molten material of said feed reservoir feeding said mould cavity under pressure exerted on said molten material.  
   
   
       6 . A method according to  claim 2 , said runner communicating with said feed reservoir and said feed reservoir communicating with said mould cavity, so that said molten material is fed to said mould cavity through said feed reservoir from said runner.  
   
   
       7 . A method according to  claim 1 , said method including feeding said molten material upwardly counter to gravity through said feed pipe to said mould cavity.  
   
   
       8 . A method according to  claim 7 , said molten material being fed substantially vertically to said mould cavity.  
   
   
       9 . A method according to  claim 7 , said molten material being fed at an angle of about 45° to said mould cavity relative to vertical.  
   
   
       10 . A method according to  claim 7 , said valve arrangement being operable for automatic closure of said runner upon pressure causing said molten material to flow counter to gravity being released.  
   
   
       11 . A method according to  claim 1 , said valve arrangement includes a ball which floats within the molten material as it flows through said runner under pressure and which cooperates with a valve seat to close said runner when said pressure is released and said flow of molten material stops or reverses, said valve being formed from a sacrificial material which can survive at the temperature of the molten material during casting, but which decomposes at an elevated temperature, said method including removing solidified material from said cast product which has solidified outside of said mould cavity, subjecting said solidified material to said elevated temperature to melt said solidified material and to decompose said ball, for recovery of said solidified material for re-use.  
   
   
       12 . A method according to  claim 11 , said ball being formed of fly-ash.  
   
   
       13 . A method according to  claim 1 , wherein inversion of said mould occurs following disconnection of said feed pipe from said mould and before said mould is relatively displaced from said feed pipe.  
   
   
       14 . A method according to  claim 1 , wherein inversion of said mould occurs following disconnection of said feed pipe from said mould and displacement of said mould relative to said feed pipe.  
   
   
       15 . A method according to  claim 1 , an array of moulds being arranged in a circular layout and said method including rotating the array for connection of each mould successively with said feed pipe.  
   
   
       16 . A method according to  claim 15 , said array being rotated at a speed such that a cast product solidifies in a mould of said array and is removed from said mould prior to returning to said feed pipe.  
   
   
       17 . A method according to  claim 1 , an array of moulds being arranged on a conveyor to convey said moulds to and from said feed pipe.  
   
   
       18 . A method according to  claim 1 , said feed pipe being arranged for movement relative to an array of stationary moulds.  
   
   
       19 . A method according to  1 , including injecting gas into the mould cavity during solidification of the cast product within the mould cavity, said gas being a gas which has a higher heat transfer coefficient than air.  
   
   
       20 . A method according to  claim 19 , said gas being helium.  
   
   
       21 . A method according to  1 , including cooling said mould to hasten solidification of said cast product, by air and/or water cooling.  
   
   
       22 . A method according to  claim 1 , said mould being a permanent mould.  
   
   
       23 . A casting apparatus including a mould having a mould cavity, and a runner which communicates with said mould cavity, a feed pipe for connection to said mould for feeding molten material to said mould cavity through said runner, a valve arrangement for closing said runner to material flow upon receipt within said mould cavity of sufficient molten material, said apparatus being operable to disconnect said feed pipe from said mould following closure of said runner by said valve arrangement and said mould being mounted for inversion following said disconnection, said apparatus further being operable to relatively displace said mould and said feed pipe for connection of said feed pipe to a further mould of said apparatus.  
   
   
       24 . An apparatus according to  claim 23 , said mould being a permanent mould.  
   
   
       25 . An apparatus according to  claim 23 , wherein said mould includes a feed reservoir in communication with said mould cavity for feeding molten material to said mould cavity upon inversion of said mould and while said molten material in said mould cavity solidifies.  
   
   
       26 . An apparatus according to  claim 25 , said feed reservoir being positioned above said mould cavity in the inverted condition of said mould.  
   
   
       27 . An apparatus according to  claim 25 , wherein said runner communicates with said feed reservoir.  
   
   
       28 . An apparatus according to  claim 23 , said valve arrangement includes a ball which is lifted away from a valve seat upon flow of molten metal toward said mould cavity and which seats against the valve seat when the flow of molten material to said mould cavity stops or reverses, to close said runner.  
   
   
       29 . An apparatus according to  claim 28 , shifting means being provided to shift said ball from an open position displaced from said valve seat, to a closed position in engagement with said valve seat.  
   
   
       30 . An apparatus according to  claim 29 , said shifting means including rod or plunger which is mounted to engage said ball and to shift said ball to said closed position.  
   
   
       31 . An apparatus according to  claim 29 , said shifting means being connected to said ball for movement of said ball between said open and closed positions.  
   
   
       32 . An apparatus according to  claim 28 , said ball being formed to float in said molten material.  
   
   
       33 . An apparatus according to  claim 28 , said ball being biased away from said valve seat and whereby an actuating mechanism is operable to shift said ball into seated engagement with said valve seat.  
   
   
       34 . An apparatus according to  claim 28 , said ball being formed from a sacrificial material which can survive at the temperature of the molten material during casting, but which decomposes at an elevated temperature.  
   
   
       35 . An apparatus according to  claim 34 , said ball being formed of fly-ash.  
   
   
       36 . An apparatus according to  claim 23 , said valve arrangement comprises a rotational valve member which is mounted to act across the runner and is rotatable between open and closed positions.  
   
   
       37 . An apparatus according to  claim 23 , a plurality of moulds being provided in a circular array and said array being rotatable incrementally into a position for connection between successive moulds of said array and said feed pipe.  
   
   
       38 . An apparatus according to  claim 23 , wherein said feed pipe shifts between successive moulds into connection therewith.