Method for the filtration of molten metal in a crucible type furnace

Claim 2

In the filtration of molten metal with a removable filter plate the method which comprises: providing a furnace crucible having means to charge said furnace crucible with molten metal; providing a ladling crucible means comprising a filter element having an open cell structure characterized by a plurality of interconnected voids; inserting said ladling crucible means in said furnace crucible wherein said ladling crucible slides on a support; and charging said furnace crucible with molten metal wherein said molten metal passes from said furnace crucible through said filter element into said ladling crucible, thereby removing impurities from the molten metal.

Claim 3

The method of claim 1 wherein said filter element is in the form of a ceramic foam filter.

Claim 4

The method of claim 2 wherein said ceramic foam filter element has an air permeability in the range of 400 to 8,000 × 10 -7 cm 2 , a porosity of 0.80 to 0.95 and a pore size of 5 to 45 pores per linear inch.

Claim 5

In the filtration of molten metal with a removable filter plate the method which comprises: providing a furnace crucible having means to charge said furnace crucible with molten metal; providing a ladling crucible means comprising a member having an open top, side walls, and a bottom; forming said open top of an imperforated material which is substantially unaffected by said molten metal; providing said open top with a bevelled peripheral surface adapted to receive said side walls of said ladling crucible means; forming said ladling crucible means in part of an element having an open cell structure characterized by a plurality of interconnected voids; inserting said ladling crucible means in said furnace crucible; and charging said furnace crucible with molten metal wherein said molten metal passes from said furnace crucible through said filter element into said ladling crucible, thereby removing impurities from the molten metal.

Claim 6

In the filtration of molten metal with a removable filter plate the method which comprises: providing a furnace crucible having means to charge said furnace crucible with molten metal; providing a ladling crucible means comprising a member having an open top, side walls, and a bottom; forming said open top of an imperforated material which is substantially unaffected by said molten metal; providing said open top with a bevelled peripheral surface adapted to receive said side walls of said ladling crucible means; forming said ladling crucible means in part of an element having an open cell structure characterized by a plurality of interconnected voids; inserting said ladling crucible means in said furnace crucible; and charging said furnace crucible with molten metal wherein said molten metal passes from said furnace crucible through said filter element into said ladling crucible, thereby removing impurities from the molten metal.

Claim 7

The method of claim 4 wherein said side walls are formed with a bevelled peripheral surface adapted to mate with said bevelled surface of said open top and including a resilient sealing means on said bevelled surface of said side walls.

Claim 8

The method of claim 5 wherein said ladling crucible means is adapted to slide on a support within said furnace crucible.

Claim 9

The method of claim 6 wherein said element is a ceramic foam filter.

Claim 10

The method of claim 7 wherein said ceramic foam filter has an air permeability in the range of 400 to 8,000 × 10 -7 cm 2 , a porosity of 0.80 to 0.95 and a pore size of 5 to 45 pores per linear inch.

Claim 11

In the filtration of molten metal with a removable filter plate the method which comprises: providing a furnace crucible having means to charge said furnace crucible with molten metal; providing a ladling crucible means comprising a filter element having an open cell structure characterized by a plurality of interconnected voids; providing said furnace crucible with a surface adapted to receive said ladling crucible means; and charging said furnace crucible with molten metal wherein said molten metal passes from said furnace crucible through said filter element into said ladling crucible, thereby removing impurities from the molten metal.

Claim 12

In the filtration of molten metal with a removable filter plate the method which comprises: providing a furnace crucible having means to charge said furnace crucible with molten metal; providing a ladling crucible means comprising a filter element having an open cell structure characterized by a plurality of interconnected voids; providing said furnace crucible with a surface adapted to receive said ladling crucible means; and charging said furnace crucible with molten metal wherein said molten metal passes from said furnace crucible through said filter element into said ladling crucible, thereby removing impurities from the molten metal.

Claim 13

The method of claim 9 wherein said furnace crucible comprises a base wherein said base is formed with a groove having a bevelled side wall surface adapted to receive said ladling crucible means.

Claim 14

The method of claim 10 wherein said ladling crucible means is provided with a bevelled peripheral surface adapted to removably mate with said bevelled surface of said groove in said base.

Claim 15

The method of claim 11 wherein said ladling crucible means is formed of a hollow enclosure wherein the interior of said hollow enclosure forms said ladling compartment.

Claim 16

The method of claim 12 wherein said filter element is ceramic foam.

Claim 17

The method of claim 13 wherein said ceramic foam material has an air permeability in the range of 400 to 8,000 × 10 -7 cm 2 , a porosity of 0.80 to 0.95 and a pore size of 5 to 45 pores per linear inch.