Method and apparatus for producing hollow microspheres

Claim 1

A method for making hollow microspheres from an inorganic film forming 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 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.

Claim 2

A method for making hollow microspheres from an inorganic film forming 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 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.

Claim 15

A method for making filamented, hollow glass microspheres having a high contained vacuum, which comprises heating glass to form molten glass, forming a liquid film of molten glass across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey metal vapor blowing gas to the inner surface of the liquid film and an outer nozzle to convey molten glass 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 glass under pressure through said gap and forming said thin film of molten glass across said orifice of the blowing nozzle, applying said metal vapor 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 glass 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 connecting glass filaments between microspheres, 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 fluid 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, surface tension forces causing the detached microsphere to form a spherical shape, and cooling, solidifying and hardening said microsphere to obtain microspheres of 500 to 6,000 microns diameter and 0.5 to 400 microns wall thickness, said microspheres being connected by thin filamented portions that are continuous with the glass microspheres, and depositing said metal vapor as a thin metal coating 50° to 600° A. thick on the innerwall surface of the microspheres to form filamented microspheres having a contained vacuum having a pressure at ambient temperature which is about the vapor pressure of said metal at ambient temperature.

Claim 16

A method for making filamented, hollow glass microspheres having a high contained vacuum, which comprises heating glass to form molten glass, forming a liquid film of molten glass across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey metal vapor blowing gas to the inner surface of the liquid film and an outer nozzle to convey molten glass 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 glass under pressure through said gap and forming said thin film of molten glass across said orifice of the blowing nozzle, applying said metal vapor 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 glass 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 connecting glass filaments between microspheres, 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 fluid 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, surface tension forces causing the detached microsphere to form a spherical shape, and cooling, solidifying and hardening said microsphere to obtain microspheres of 500 to 6,000 microns diameter and 0.5 to 400 microns wall thickness, said microspheres being connected by thin filamented portions that are continuous with the glass microspheres, and depositing said metal vapor as a thin metal coating 50° to 600° A. thick on the innerwall surface of the microspheres to form filamented microspheres having a contained vacuum having a pressure at ambient temperature which is about the vapor pressure of said metal at ambient temperature.

Claim 24

A method for making hollow glass microspheres which comprises heating glass to form molten glass, forming a liquid film of molten glass 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 microspheres from said orifice.

Claim 25

A method for making hollow glass microspheres which comprises heating glass to form molten glass, forming a liquid film of molten glass 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 microspheres from said orifice.

Claim 27

A method for making hollow glass microspheres which comprises heating glass to form molten glass, forming a liquid film of molten glass across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey an inert gas or metal vapor blowing gas to the inner surface of the liquid film and an outer nozzle to convey said molten glass at a temperature of 2000° to 2800° F., to said orifice, applying said inert gas or a metal vapor 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 an elongated cylinder shaped liquid film of molten glass which is closed at its outer end and connected at its inner end to the outer edge of the orifice of said blowing nozzle, continuously feeding said molten glass to said nozzle while said elongated cylinder is being formed, directing an entraining fluid at said coaxial blowing nozzle at an angle of 25° to 75° 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, whereby said entraining fluid envelops and acts on the elongated cylinder to flap, fold, pinch and close-off said elongated cylinder at its inner end at a point proximate to the coaxial blowing nozzle and said entraining fluid acting through drag forces on said cylinder to detach the cylinder from the coaxial blowing nozzle whereby surface tension forces cause the cylinder to form a spherical shape microsphere and directing a quench fluid into contact with said microsphere to rapidly cool and solidify said microsphere.

Claim 28

A method for making hollow glass microspheres which comprises heating glass to form molten glass, forming a liquid film of molten glass across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey an inert gas or metal vapor blowing gas to the inner surface of the liquid film and an outer nozzle to convey said molten glass at a temperature of 2000° to 2800° F., to said orifice, applying said inert gas or a metal vapor 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 an elongated cylinder shaped liquid film of molten glass which is closed at its outer end and connected at its inner end to the outer edge of the orifice of said blowing nozzle, continuously feeding said molten glass to said nozzle while said elongated cylinder is being formed, directing an entraining fluid at said coaxial blowing nozzle at an angle of 25° to 75° 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, whereby said entraining fluid envelops and acts on the elongated cylinder to flap, fold, pinch and close-off said elongated cylinder at its inner end at a point proximate to the coaxial blowing nozzle and said entraining fluid acting through drag forces on said cylinder to detach the cylinder from the coaxial blowing nozzle whereby surface tension forces cause the cylinder to form a spherical shape microsphere and directing a quench fluid into contact with said microsphere to rapidly cool and solidify said microsphere.

Claim 38

An apparatus for blowing hollow inorganic film forming material microspheres comprising a coaxial blowing nozzle consisting of an inner nozzle having an inner orifice at the lower end thereof for a blowing gas and an outer nozzle having an outer orifice for said material, said inner nozzle orifice being disposed proximate to said outer orifice, there being disposed external to said blowing nozzle means cooperating with said blowing nozzle by which there is induced 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.

Claim 39

An apparatus for blowing hollow inorganic film forming material microspheres comprising a coaxial blowing nozzle consisting of an inner nozzle having an inner orifice at the lower end thereof for a blowing gas and an outer nozzle having an outer orifice for said material, said inner nozzle orifice being disposed proximate to said outer orifice, there being disposed external to said blowing nozzle means cooperating with said blowing nozzle by which there is induced 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.

Claim 40

An apparatus for blowing hollow glass microspheres comprising means for holding molten glass, a coaxial blowing nozzle consisting of an inner nozzle having an inner orifice at the lower end thereof for a blowing gas and an outer nozzle having an outer orifice for molten glass, said inner nozzle orifice being disposed proximate to said outer orifice, there being disposed external to said blowing nozzle a transverse jet cooperating with said blowing nozzle by which an entraining fluid is directed at said coaxial blowing nozzle at an angle of 25 to 75 relative to a line drawn through the center axis of said coaxial blowing nozzle such that said entraining fluid dynamically induces 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.

Claim 41

An apparatus for blowing hollow glass microspheres comprising means for holding molten glass, a coaxial blowing nozzle consisting of an inner nozzle having an inner orifice at the lower end thereof for a blowing gas and an outer nozzle having an outer orifice for molten glass, said inner nozzle orifice being disposed proximate to said outer orifice, there being disposed external to said blowing nozzle a transverse jet cooperating with said blowing nozzle by which an entraining fluid is directed at said coaxial blowing nozzle at an angle of 25 to 75 relative to a line drawn through the center axis of said coaxial blowing nozzle such that said entraining fluid dynamically induces 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.

Claim 47

A method for making hollow glass microspheres which comprises heating glass to form molten glass, forming a liquid film of molten glass 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 glass 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 glass 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, surface tension forces causing the detached microsphere to form a spherical shape, and cooling and solidifying said microsphere.

Claim 48

A method for making hollow glass microspheres which comprises heating glass to form molten glass, forming a liquid film of molten glass 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 glass 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 glass 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, surface tension forces causing the detached microsphere to form a spherical shape, and cooling and solidifying said microsphere.

Claim 51

An apparatus for blowing hollow inorganic film forming material microspheres comprising means for holding molten material, a coaxial blowing nozzle comprising an inner nozzle having an inner orifice at the lower end thereof for a blowing gas and an outer nozzle having an outer orifice for said molten material, and means for feeding said molten liquid material to said coaxial nozzle, said inner nozzle orifice being disposed proximate to said outer orifice, there being disposed external to said blowing nozzle means cooperating with said blowing nozzle by which there is induced 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.

Claim 52

An apparatus for blowing hollow inorganic film forming material microspheres comprising means for holding molten material, a coaxial blowing nozzle comprising an inner nozzle having an inner orifice at the lower end thereof for a blowing gas and an outer nozzle having an outer orifice for said molten material, and means for feeding said molten liquid material to said coaxial nozzle, said inner nozzle orifice being disposed proximate to said outer orifice, there being disposed external to said blowing nozzle means cooperating with said blowing nozzle by which there is induced 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.

Claim 54

An apparatus for blowing hollow glass microspheres comprising means for holding molten glass, a coaxial blowing nozzle comprising an inner nozzle having an inner orifice at the lower end thereof for a blowing gas and an outer nozzle having an outer orifice for the molten glass, and means for feeding said molten glass to said coaxial nozzle, said inner nozzle orifice being disposed proximate to said outer orifice, there being disposed external to said blowing nozzle a transverse jet cooperating with said blowing nozzle by which an entraining fluid is directed at said coaxial blowing nozzle at an angle relative to a line drawn through the center axis of said coaxial blowing nozzle such that said entraining fluid dynamically induces 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.

Claim 55

An apparatus for blowing hollow glass microspheres comprising means for holding molten glass, a coaxial blowing nozzle comprising an inner nozzle having an inner orifice at the lower end thereof for a blowing gas and an outer nozzle having an outer orifice for the molten glass, and means for feeding said molten glass to said coaxial nozzle, said inner nozzle orifice being disposed proximate to said outer orifice, there being disposed external to said blowing nozzle a transverse jet cooperating with said blowing nozzle by which an entraining fluid is directed at said coaxial blowing nozzle at an angle relative to a line drawn through the center axis of said coaxial blowing nozzle such that said entraining fluid dynamically induces 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.

Claim 60

A method for making hollow glass microspheres having a high contained vacuum which comprises heating glass to form molten glass, forming a liquid film of molten glass across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey metal vapor blowing gas to the inner surface of the liquid film and an outer nozzle to convey molten glass 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 glass under pressure through said gap and forming said thin film of molten glass across said orifice of the blowing nozzle, applying said metal vapor 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 glass 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, surface tension forces causing the detached microsphere to form a spherical shape, and cooling, solidifying and hardening said microsphere to obtain microspheres of 500 to 6,000 microns diameter and 0.5 to 400 microns wall thickness, and depositing said metal vapor as a thin metal coating 50° to 600° A. thick on the innerwall surface of the microspheres to form microspheres having a contained vacuum having a pressure at ambient temperature which is about the vapor pressure of said metal at ambient temperature.

Claim 61

A method for making hollow glass microspheres having a high contained vacuum which comprises heating glass to form molten glass, forming a liquid film of molten glass across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey metal vapor blowing gas to the inner surface of the liquid film and an outer nozzle to convey molten glass 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 glass under pressure through said gap and forming said thin film of molten glass across said orifice of the blowing nozzle, applying said metal vapor 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 glass 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, surface tension forces causing the detached microsphere to form a spherical shape, and cooling, solidifying and hardening said microsphere to obtain microspheres of 500 to 6,000 microns diameter and 0.5 to 400 microns wall thickness, and depositing said metal vapor as a thin metal coating 50° to 600° A. thick on the innerwall surface of the microspheres to form microspheres having a contained vacuum having a pressure at ambient temperature which is about the vapor pressure of said metal at ambient temperature.