Patent ID: 8181486
Filing Date: 2012-05-22
Classification: C03B,Y02P

Abstract:
1. A method for manufacturing preforms for press molding in which a glass melt gob is separated from glass melt flow flowing out of a pipe and said glass melt gob is molded into a preform for press molding on a glass gob casting mold, comprising the steps of: receiving a front end of said glass melt flow on a glass receiving surface of a supporting member positioned beneath said pipe, said supporting member having a plurality of gas-blowing holes arranged on the glass receiving surface, dropping said supporting member downward to separate a glass melt gob from said glass melt flow, and transferring said glass melt gob onto the glass gob casting mold to conduct a molding step, wherein during a period from when the front end of said glass melt flow is received on the glass receiving surface of the supporting member in said receiving step to when said glass melt gob is transferred onto the glass gob casting mold in said transferring step, the period being in a range from 3 seconds to 20 seconds, said glass melt is supported in a state of contact with said glass receiving surface of said supporting member and heat of said glass melt is removed with thermal conduction to increase viscosity of said glass melt in a viscosity-increasing step, and following increasing viscosity said glass melt, an operation in which said glass melt is floated on said supporting member is conducted, and wherein said supporting member is comprised of multiple dividing members capable of separating and joining together in a cross direction; with said dividing members in a joined state, the glass melt supported is held for a prescribed period in a state of contact with a surface of said supporting member; and while said glass melt is in contact with said surface of said supporting member, gas flow is initiated from said gas-blowing holes on the glass receiving surface of said supporting member to float said glass gob, after which said dividing members are separated from each other to drop said glass gob vertically to transfer said glass gob onto said casting mold.