Apparatus for purifying molten metal

• US 4,351,514 A
• Filed: 07/18/1980
• Issued: 09/28/1982
• Est. Priority Date: 07/18/1980
• Status: Expired due to Term

• Current Assignee: Fenton C. Koch
• Original Assignee: Fenton C. Koch
• Inventors: Koch, Fenton C.
• Primary Examiner(s): Peters, G. O.
• Application Number:
  US06/169,998
• Time in Patent Office: 802 Days
• Field of Search: 266/217, 266/233, 266/235, 75/68 R, 75/93 R, 75/93 E, 261/29, 261/93 R, 261/DIG. 75, 417/66
• US Class Current: 266/217
• CPC Class Codes: C21C 7/00 Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 treating molten metals during moulding B22D1/00, B22D27/00; remelting ferrous metals C22B
• CPC Class Codes: F04D 7/065 for liquid metal
• CPC Class Codes: Y10S 261/75 Flowing liquid aspirates gas

Abstract

An improved molten metal pump and gas injection apparatus comprising a submersible pump housing 10 enclosing a rotatable impeller 30, an impeller drive 12 supported above the housing and an elongate drive shaft 16 operatively connected to the impeller. Rotation of the drive shaft effects fluid flow between a pump inlet 35 and a pump outlet 44 both being at least partially defined by the impeller housing. A gas injection conduit 54 extends downwardly from a drive motor support platform 20 and includes an output end 54a that terminates near the pump inlet and which is received by a gas inlet collar 58 that defines a venturi 60, coaxial with the axis of the pump inlet. A passage 62 formed in the collar communicates the end of the gas injection conduit with the throat of the venturi so that the gas is injected into the incoming molten metal in an area of low pressure, thereby reducing the gas pressure needed to effect injection.

Claims

1. Apparatus for purifying molten metal such as aluminum or the like, comprising:

(a) structure defining a reservoir containing molten metal to be treated;

(b) an impeller housing submerged below the surface of molten metal in said reservoir;

(c) a rotatable pump impeller and a cooperating volute mounted within said housing, together defining an impeller chamber that extends into fluid communication with structure defining an outlet passage for said chamber, said passage disposed below the surface of molten metal;

(d) an impeller drive supported on a platform located above the surface of molten metal and operatively connected to the impeller by a drive shaft, said drive shaft defining an axis of rotation for said impeller;

(e) said impeller housing defining an inlet through which molten metal from said reservoir is drawn upon rotation of said impeller, said inlet located in coaxial alignment with said impeller;

(f) a gas injection conduit in fluid communication with a source of purifying gas, including an output end disposed below the surface of molten metal, in proximity to the inlet; and

,

(g) a gas injection means located at said inlet including means for receiving the output end of said gas injection conduit and a passage means communicating said output end with said inlet so that gas discharged by said conduit is injected and mixed with molten metal drawn into said inlet during rotation of said impeller, said gas reacting with impurities in said molten metal as said metal travels through said impeller chamber and outlet passage.

2. The purifying apparatus of claim 1 wherein said impeller chamber outlet passage opens into said reservoir so that molten metal is discharged by said outlet passage, below the surface of the reservoir.

3. The apparatus of claim 1, wherein said gas injection means defines a venturi coaxial with said inlet and said passage means communicates the output end of said conduit with the throat of said venturi.

4. The apparatus of claim 1, wherein an upper end of said conduit is releasably fastened to said drive platform and said gas injection member is rotatable thereby allowing said conduit to be alternately positioned along the perimeter of the purifying apparatus.

5. The apparatus of claim 1, wherein said outlet passage is connected to a discharge riser pipe that extends above the surface of the molten metal.