Back to results
US 4,415,512 AGranted
Method and apparatus for producing hollow metal microspheres and microspheroids
OwnerLeonard B. Torobininventor
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
OwnerLeonard B. Torobininventor
Estimating the term…
Hollow metal microspheres are made by forming a liquid film of molten film forming metal composition across a coaxial blowing nozzle and applying a blowing gas at a positive pressure on the inner surface of the metal film to blow the film and form an elongated cylinder shaped liquid film of molten metal. An inert entraining fluid is directed over and around the blowing nozzle at an angle to the axis of the blowing nozzle so that the entraining fluid dynamically induces a pulsating or fluctuating pressure field at the opposite side of the blowing nozzle in the wake of the coaxial blowing nozzle. The continued movement of the entraining fluid produces asymmetric fluid drag forces on the cylinder and closes and detaches the elongated cylinder from the coaxial blowing nozzle. Surface tension forces acting on the detached cylinder form the latter into a spherical shape which is rapidly cooled and solidified by cooling means to form a hard, smooth hollow metal microsphere. A thin metal coating can be deposited on the inner wall surface of the microspheres by using a metal vapor as the blowing gas or by adding to the blowing gas small dispersed metal particles and/or gases of organometallic compounds which are decomposed. The metal microspheres can be used to make insulation materials systems and as filler materials in plastics, plastic foam compositions, rubber and rubber compositions and in metal compositions. Filamented hollow metal microspheres with a thin metal filament connecting adjacent metal microspheres are also disclosed.
A method for making hollow metal microspheres from a film forming metal material which comprises heating said material, forming a liquid film of said material across an orifice, applying a blowing gas at a positive pressure on the inner surface of the liquid film to blow the film and form the microsphere, subjecting the microsphere during its formation to an external pulsating or fluctuating pressure field having periodic osciallations, said pulsating or fluctuating pressure field acting on said microsphere to assist in its formation and to assist in detaching the microsphere from said orifice.
A method for making hollow metal microspheres which comprises heating a film forming metal composition to form molten metal, forming a liquid film of molten metal across an orifice, applying a blowing gas at a positive pressure on the inner surface of the liquid film to blow the film and form a microsphere, subjecting the microsphere during its formation to a pulsating or fluctuating pressure field having periodic oscillations, said pulsating or fluctuating pressure field acting on said microsphere to assist in its formation and to assist in detaching the microsphere from said orifice.
A method for making hollow film forming metal material microspheres which comprises heating said metal material to form molten metal, forming a liquid film or molten metal across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey a blowing gas to the inner surface of the liquid film and an outer nozzle to convey said molten metal to said orifice, applying said blowing gas through said inner nozzle at positive pressure on the inner surface of the liquid film to blow the film downwardly and outwardly to form the microsphere, continuously feeding said molten metal to said outer nozzle while said microsphere is being formed, directing an entraining fluid at said coaxial blowing nozzle at an angle relative to a line drawn through the center axis of said coaxial blowing nozzle, said entraining fluid passing over and around said coaxial blowing nozzle to fluid dynamically induce a pulsating or fluctuating pressure field having periodic oscillations at the opposite or lee side of the blowing nozzle in the wake or shadow of said blowing nozzle, said entraining fluid acting on the microsphere to pinch and close-off the microsphere at a point proximate to the coaxial blowing nozzle and said entraining fluid acting to detach the microsphere from the coaxial blowing nozzle and rapidly cooling and solidifying said microsphere.
A method for making hollow film forming metal material microspheres which comprises heating metal glass alloy material to form molten metal, forming a liquid film of molten metal across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey blowing gas to the inner surface of the liquid film and an outer nozzle to convey molten metal to said orifice, the lower portion of said outer nozzle being tapered inwardly to form with the outer edge of the inner nozzle a fine gap, feeding the molten metal under pressure through said gap and forming said thin film of molten metal across said orifice of the blowing nozzle, applying said blowing gas through said inner nozzle at positive pressure on the inner surface of the liquid film to blow the film downwardly and outwardly to form a microsphere, continuously feeding said molten metal to said outer nozzle while said microsphere is being formed, directing an entraining fluid at said coaxial blowing nozzle at an angle relative to a line drawn through the center axis of said coaxial blowing nozzle, said entraining fluid passing over and around said coaxial blowing nozzle to fluid dynamically induce a pulsating or fluctuating pressure field having periodic oscillations at the opposite or lee side of the blowing nozzle in the wake or shadow of said blowing nozzle, said entraining fluid acting on the microsphere to pinch and close-off the microsphere at a point proximate to the coaxial blowing nozzle and said entraining fluid acting to detach the microsphere from the coaxial blowing nozzle, and rapidly cooling, solidifying and hardening said microsphere to obtain microspheres having a 500 to 6,000 microns diameter and a 0.5 to 400 microns wall thickness.
A method for making filamented, hollow film forming metal material microspheres which comprises heating metal glass alloy material to form molten metal, forming a liquid film of molten metal across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey blowing gas to the inner surface of the liquid film and an outer nozzle to convey molten metal to said orifice, the lower portion of said outer nozzle being tapered inwardly to form with the outer edge of the inner nozzle a fine gap, feeding the molten metal under pressure through said gap and forming said thin film of molten metal across said orifice of the blowing nozzle, applying said blowing gas through said inner nozzle at positive pressure on the inner surface of the liquid film to blow the film downwardly and outwardly to form a microsphere, continuously feeding said molten metal to said outer nozzle while said microsphere is being formed, directing an entraining fluid at said coaxial blowing nozzle, at a linear velocity in the region of microsphere formation of about 1 to 50 feet per second to obtain a connecting metal filament which is continuous with said microsphere and the next microsphere forming at the blowing nozzle, and at an angle relative to a line drawn through the center axis of said coaxial blowing nozzle, said entraining fluid passing over and around said coaxial blowing nozzle to fluid dynamically induce a pulsating or fluctuating pressure field having periodic oscillations at the opposite or lee side of the blowing nozzle in the wake or shadow of said blowing nozzle, said entraining fluid acting on the microsphere to pinch and close-off the microsphere at a point proximate to the coaxial nozzle and said entraining fluid acting to detach the microsphere and connecting metal filament from the coaxial blowing nozzle, and rapidly cooling, solidifying and hardening said microsphere and connecting metal filament to obtain microspheres having a 500 to 6,000 microns diameter and a 0.5 to 400 microns wall thickness, said mircospheres being connected by thin filamented portions between microspheres that are continuous with the metal glass alloy material microspheres.
Dependencies are inferred from the claim text.