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CA-3034562-C - SCRAP SUBMERGENCE DEVICE

CA3034562CCA 3034562 CCA3034562 CCA 3034562CCA-3034562-C

Abstract

A molten metal scrap submergence system comprising a furnace and a vortexing scrap submergence well. The vortexing scrap submergence well includes a diverter suspended above the well and oriented for immersion in a bath of molten metal circulating within the well. The system, or an alternative scrap submergence system, can include a hood element disposed in an overlapping position with regard to a top opening of the scrap submergence well. The hood at least substantially seals the top opening. The hood element includes a scrap piece feed chute and a burner allowing carbon containing vapor evaporated from the surface of the molten scrap pieces to combust and form predominantly water. The system, or an alternative scrap submergence system can include internal side walls of the well with a first diameter portion adjacent and above said ramp and a second, larger diameter portion above said first portion.

Inventors

  • Richard S. Henderson
  • Chris T. Vild
  • Jason Tetkoskie

Assignees

  • PYROTEK, INC.

Dates

Publication Date
20260505
Application Date
20170829
Priority Date
20160829

Claims (14)

  1. CLAIMS: 1. A molten metal scrap submergence system comprising a furnace and a vortexing scrap submergence well, said vortexing scrap submergence well relying on the shape of a chamber of the scrap submergence well to create a molten metal flow which submerges scrap pieces without rotation of a rotor, said vortexing scrap submergence well including a diverter suspended above the well and oriented for immersion in a bath of molten metal circulating within said well, said diverter slowing the egress of scrap from a scrap submergence well outlet, and wherein the vertical position of the diverter is adjustable.
  2. 2. The system of claim 1 wherein said diverter is cylindrical.
  3. 3. The system of claim 1 wherein said diverter is pyramidal.
  4. 4. The system of claim 1 wherein said diverter comprises a disk suspended from a post.
  5. 5. The system of claim 2 wherein said diverter comprises a drum.
  6. 6. The system of claim 5 wherein said drum includes one or both of an open top end and an open top bottom.
  7. 7. The system of claim 1 wherein said diverter has a diameter substantially equal to or larger than a diameter of an exit from said well.
  8. 8. The system of claim 1 further including a mechanism for raising and lowering said diverter.
  9. 9. The system of claim 1 further comprising a hood element disposed in an overlapping position with said well. 14 Date Re1rue/Date Received 2024-02-22
  10. 10. The system of claim 1 wherein said scrap submergence well defines a chamber housing a ramp and wherein said chamber has a first diameter adjacent to the ramp and a second greater diameter above the ramp.
  11. 11. The system of claim 1 wherein said diverter includes a densifying material cast therein.
  12. 12. The system of claim 1 further comprising at least one projection extending from said vortexing scrap submergence well and engaging said diverter to provide stability thereto.
  13. 13. The system of claim 9 wherein said hood is a cylinder.
  14. 14. The system of claim 13 further comprising a thermocouple measuring a temperature within said hood element and automatically activating a burner when the temperature falls below about 1200°F. Date Re1rue/Date Received 2024-02-22

Description

SCRAP SUBMERGENCE DEVICE This application claims the benefit of U.S. Provisional Application No. 62/380,582, filed August 29, 2016 and U.S. Provisional Application No. 62/488,235, filed April 21, 2017. BACKGROUND [0001] The present exemplary embodiment relates to a scrap submergence device. The technology of the present disclosure relates generally to melting pieces of metal and, more particularly, to a reverbatory furnace system for melting light gauge metal stock. As used herein, the term "metal" means any metal or combination of metals, such as aluminum, copper, iron, zinc, magnesium and alloys thereof. [0002] The production, processing, and recycling of metals, such as aluminum, commonly requires melting metal stock, such as scrap stock, that has a high surface area to weight ratio (also referred to as light gauge stock). Examples of such material include scalper chips generated from milling rolling ingots, turnings or swart from lathe or sawing operations, and output from crushers or shredders used to recycle aluminum sheet, extrusions, or cast shapes. The material is typically melted in a melting chamber of a melting furnace such as a rotary furnace or a reverb furnace. [0003] Light gauge aluminum scrap is intrinsically difficult to efficiently melt because aluminum and its alloys readily oxidize. The process of oxidation turns the surface from aluminum, a valuable metal, to aluminum oxide, a non-metallic mineral of comparatively lower value. Unprotected aluminum surfaces oxidize rapidly in air, even at ambient temperatures. When exposed to temperatures high enough to melt aluminum, the oxidation process is greatly accelerated. Thus, if aluminum is exposed to air at such temperatures, oxidation can completely consume aluminum having thin cross sections, that is, aluminum with a high surface area to weight ratio. However, melting thin walled scrap pieces is difficult because rapid submerging in molten metal is severely hampered by the fact that thin walled scrap pieces float on molten metal ("floating scrap"). Accordingly, melting typically includes a step of actively submerging the light gauge scrap under the surface of the molten metal. 1 Date Re9ue/Date Received 2024-02-22 [0004] Various devices have been used to submerge metal scrap in molten metal. Typically, molten metal contained in a hearth is circulated by a pump contained in a pump well. In one design, molten metal is drawn from the hearth by the pump and circulated from the pump well to a scrap charging well, to a dross well and back to the hearth. Scrap metal such as aluminum is added to molten metal in the charge well. Referring to FIG. 1, an aluminum recycling furnace 10 is depicted. Furnace 10 includes a main hearth component 12 which is heated, for example, with gas or oil burners or by any other means known in the art. Adjacent, and in fluid communication with the hearth 12 (typically via submerged archways), is the primary recycling area comprised of a pump well 14, a charge well 16 and a dross well 18. Although not shown, the wall of hearth 12 opens to the pump well 14, the pump well opens to the charge well 16, the charge well opens to the dross well 18, and the dross well opens to the hearth 12 to allow the circulation pattern shown by the arrows. The pump well can include a mechanical molten metal pump of any type known to those skilled in the art. Alternatively, the well and pump can be replaced by an electromagnetic pump, for example. The molten metal pump circulates molten metal from the hearth 12 to the charge well 16 where scrap chips of the metal to be recycled are deposited onto the surface of the melt. Molten metal from the charge well 16 flows into the dross well 18 wherein impurities in the form of dross are skimmed from the surface before the melt flows back into the hearth 12. [0005] A variety of apparatus have been used in the charge well to facilitate the submergence of the scrap metal below the surface of the molten metal bath. Three major types of systems exist. [0006] The first type includes mechanical systems constructed primarily of a rotor which creates a molten metal flow from the top surface. Examples of these devices are shown in U.S. Pat. Nos. 3,873,305; 3,997,336; 4,128,415; 4,930,986; and 8,449,814. Referring now to FIG. 2, a conventional scrap melter system includes a circulation pump 90 and a scrap melter 92. A vessel 21 containing a molten metal bath 2 is generally divided into three compartments. A first compartment 1 (called a pump well) typically houses the circulation pump 90. A second compartment 3 (called a charge well) typically houses the scrap melter 92. A third compartment 7 2 Date Re9ue/Date Received 2024-02-22 (called a dross well) allows dross and oxide from the melting process to be skimmed off the molten metal 2. The circulating molten metal 2 moves between compartment 1, compartment 3, and compartment 7 and is preferably circulated throughout the vessel 21. Scrap S is introduced into co