Abstract: In the method for manufacturing preforms for press molding, a glass melt gob is separated from glass melt flow flowing out of a pipe and the glass melt gob is molded into a preform for press molding on a glass gob casting mold. The method comprises a viscosity-increasing step to increase viscosity of the glass melt.

Abstract: A method of manufacturing high-quality preforms from glass melt, manufacturing glass elements, such as lenses, by press molding these preforms and, manufacturing optical elements by reheating and press molding these glass gobs. In the method glass gobs are continuously separated from a glass melt flow continuously flowing out of a nozzle and the separated glass gobs are formed with glass forming members that are intermittently or continuously moving. A support member is made to approach the front end of the nozzle, the front end of the glass melt flow is received by the support member, and the support member is dropped more rapidly than the rate of flow of the glass melt flow to separate a glass gob from the glass melt flow. The separated glass gob is transferred from the support member to a stopped or moving glass forming member to mold a glass article.

Abstract: A process for stably and efficiently producing quality glass articles such as preforms at high yields, and a process for producing an optical device from the preform obtained by the above process. In the process for producing a glass article, molten glass gobs having a predetermined weight each are poured, or molten glass drops having a predetermined weight each are dropped through a nozzle, into a boiling liquid having a boiling point lower than the class transition temperature of the glass constituting said glass article or a liquid which is temperature-adjusted beforehand so as to be caused to boil by the amount of heat of the glass, to form glass articles.

Abstract: A process for stably and efficiently producing quality glass articles such as preforms at high yields, and a process for producing an optical device from the preform obtained by the above process. In the process for producing a glass article, molten glass gobs having a predetermined weight each are poured, or molten glass drops having a predetermined weight each are dropped through a nozzle, into a boiling liquid having a boiling point lower than the glass transition temperature of the glass constituting said glass article or a liquid which is temperature-adjusted beforehand so as to be caused to boil by the amount of heat of the glass, to form glass articles. In the process for producing an optical device, a preform obtained by the above process is softened by heating and precision-press-molded into the optical device.

Abstract: In the method for manufacturing preforms for press molding, a glass melt gob is separated from glass melt flow flowing out of a pipe and the glass melt gob is molded into a preform for press molding on a glass gob casting mold. The method comprises a viscosity-increasing step to increase viscosity of the glass melt.

Abstract: Disclosed is a method for manufacturing a molded glass object. In the method, glass melt is made to flow from the front end portion of a nozzle; a prescribed weight of the glass melt flowing out is received by a glass melt receiving portion provided on a forming mold moved beneath the nozzle, wherein multiple forming molds are sequentially moved beneath the nozzle; the glass melt gob received is moved from the glass melt receiving portion to a hollow provided on the forming mold; and in the hollow, a molded glass object is formed while blowing gas upward through a gas outlet provided in the bottom of the hollow. The method is characterized in that the front end of the nozzle is constantly positioned outside the space vertically above the gas outlet. Methods of manufacturing press molded articles of glass and optical glass elements are described.

Abstract: The present invention relates to a method of manufacturing with high production efficiency glass articles, such as high-quality preforms for press molding (press-molding preforms) from glass melt, and to a method of manufacturing glass elements, such as lenses, by press molding these preforms. Further, the present invention relates to a method of molding glass gobs suited to the press molding of preforms of high quality and high weight precision from a glass melt, and to a method of manufacturing optical elements by reheating and press molding these glass gobs. In the method of manufacturing glass articles, glass gobs are continuously separated from a glass melt flow continuously flowing out of a nozzle and the separated glass gobs are formed with glass forming members that are intermittently or continuously moving.

Abstract: A process for stably and efficiently producing quality glass articles such as preforms at high yields, and a process for producing an optical device from the preform obtained by the above process.

Abstract: Disclosed is a method of and device for manufacturing a molded glass object. In the method, glass melt is made to flow from the front end portion of a nozzle; a prescribed weight of the glass melt flowing out is received by a glass melt receiving portion provided on a forming mold moved beneath the nozzle, wherein multiple forming molds are sequentially moved beneath the nozzle; the glass melt gob received is moved from the glass melt receiving portion to a hollow provided on said forming mold; and in the hollow, a molded glass object is formed while blowing gas upward through a gas outlet provided in the bottom of the hollow. The method is characterized in that the front end of said nozzle is constantly positioned outside the space vertically above said gas outlet. Methods of manufacturing press molded articles of glass and optical glass elements are described. In these method, a molded glass object manufactured by the above method is heated, softened, and press molded or precision press molded.

Abstract: In a method of producing a glass gob by continuously dropping a molten glass 9 from a nozzle 2 in a dropping direction, a gas flow 20 is caused to continuously flow in the dropping direction along an outer peripheral surface of the nozzle 2 at a predetermined flow rate. The gas flow 20 applies a wind pressure to the molten glass 9 appearing from a nozzle end 2a of the nozzle 2 to drop the molten glass 9.

Abstract: In a method of producing a glass gob by continuously dropping a molten glass 9 from a nozzle 2 in a dropping direction, a gas flow 20 is caused to continuously flow in the dropping direction along an outer peripheral surface of the nozzle 2 at a predetermined flow rate. The gas flow 20 applies a wind pressure to the molten glass 9 appearing from a nozzle end 2a of the nozzle 2 to drop the molten glass 9.

Abstract: A pressure-resistant buoyancy material, comprising pressure-resistant hollow elements, a syntactic foam, and an empty space intervening between the pressure-resistant hollow elements and the syntactic foam, communicating with the outside of the buoyancy material. The pressure-resistant hollow elements are retained in a freely movable state in the empty space.