Abstract: The present invention is directed toward a method of reducing contamination of a glass melt by oxide particulates, such as particulates of platinum oxide, which may condense on the inside surfaces of a stir chamber, particularly the stir shaft, and fall back into the glass melt. The method includes causing a flow of gas through an annular space between the shaft and the chamber cover. In one embodiment, the flow of gas through the annular space is caused by drawing a vacuum in the chamber. An apparatus for practicing the method is also provided.

Abstract: Disclosed are refractory body and refractory vessel for reforming or reflowing glass materials. The refractory body and vessel have gas venting channels, including surface grooves and/or vias formed on the surface in contact with the glass during high temperature treatment thereof. The refractory body and vessel are particularly advantageous for reflowing fused silica glass at an elevated temperature such as above 1700° C.

Abstract: Disclosed are synthetic silica glass body with a birefringence pattern having low fast axis direction randomness factor and glass reflow process. The glass reflow process comprises steps of: providing a glass tube having a notch; and thermally reflowing the glass tube to form a glass plate. The process can be advantageously used to produce fused silica glass plate without observable striae when viewed in the direction of optical axis. Also disclosed are optical members comprising the fused silica glass body and a process for reflowing glass cylinders.

Abstract: In the formation of sheet glass by the overflow downdraw process, the width of usable sheet glass is maximized by downwardly flowing edge portions of the sheet over web-like members and thereafter over extensions which intersect with and are downwardly inclined relative to the web-like members to thin edge portions of the glass flow and maintain sheet width. The extension members are preferably removably attached to the web-like members, greatly facilitating replacement of the more easily damaged extension members.

Abstract: The present invention is directed toward a method of reducing contamination of a glass melt by oxide particulates, such as particulates of platinum oxide, which may condense on the inside surfaces of a stir chamber, particularly the stir shaft, and fall back into the glass melt. The method includes causing a flow of gas through an annular space between the shaft and the chamber cover. In one embodiment, the flow of gas through the annular space is caused by drawing a vacuum in the chamber. An apparatus for practicing the method is also provided.

Abstract: This invention provides a method and apparatus for mixing calcined gypsum. The invention comprises a mixer which employs high pressure water to eliminate or substantially reduce the formation of lumps of gypsum inside the mixer which cause paper breaks when the calcined gypsum slurry containing the lumps is used to form the gypsum core in a gypsum wallboard product. High pressure water jets direct a spray of high pressure water at the surfaces within the mixer where the lumps of gypsum are formed. The method of this invention utilizes the high pressure water as part of the metered water that is continuously fed to the mixer, with the balance of the water being fed through low pressure nozzles.