Abstract: A backup structure for an uprising pipe or a downfalling pipe of a vacuum degassing apparatus including the uprising pipe, a vacuum degassing vessel and the downfalling pipe, comprises the uprising pipe or the downfalling being made of platinum or a platinum alloy and having refractory bricks disposed therearound; and the refractory bricks having a thermal expansion relief member disposed on a top end thereof, the thermal expansion relief member comprising a material selected from a metal material and a ceramic material having a creep strength (JIS Z2271: 1993) of 35 MPa or above at 760° C.

Abstract: A backup structure for hollow tube made of platinum or a platinum alloy in which glass exudation from bricks employed for the backup is prevented, is provided and a vacuum degassing apparatus and a glass producing apparatus employing such a backup structure are provided. A backup structure for hollow tube made of platinum or platinum alloy, which is used in a high-temperature environment, which contains a fused cast refractory layer provided along an outer surface of the hollow tube made of platinum or a platinum alloy, wherein at least in a portion of the fused cast refractory layer in contact with the outer surface of the hollow tube, the component ratio of fused cast refractories containing at most 10 mass % of matrix glass phase, is at least 50 vol %.

Abstract: A backup structure for an uprising pipe or a downfalling pipe of a vacuum degassing apparatus including the uprising pipe, a vacuum degassing vessel and the downfalling pipe, comprises the uprising pipe or the downfalling being made of platinum or a platinum alloy and having refractory bricks disposed therearound; and the refractory bricks having a thermal expansion relief member disposed on a top end thereof, the thermal expansion relief member comprising a material selected from a metal material and a ceramic material having a creep strength (JIS Z2271: 1993) of 35 MPa or above at 760° C.

Abstract: The present invention provides a vacuum degassing system 10 having a leakage valve 48 installed between a condenser 46 and a vacuum pump 44, wherein even when the leakage valve 48 is opened, a vacuum degassing vessel 12 is not released to the atmosphere to thereby constantly maintain a temperature in the vacuum degassing vessel 12; and a large amount of volatile matters in the vacuum degassing vessel 12 are not discharged to a gas release pipe 34, whereby the vacuum degassing vessel 12 can be stably operated.

Abstract: A refining method for molten glass comprising a stirring step for stirring molten glass in a stirring vessel, a feeding step for feeding the molten glass into a vacuum vessel via an uprising pipe, a degassing step wherein the molten glass is put under a reduced pressure in the vacuum vessel, bubbles produced on the molten glass surface and a flow of the molten glass just below the molten glass surface are blocked by a barrier provided in the vacuum vessel, and the molten glass is degassed in a state that a bubble layer is formed on the molten glass surface, and a discharging step for discharging the molten glass after degassing from the vacuum vessel through a downfalling pipe to a storage vessel.

Abstract: A plurality of glass plates 10 are stacked in a block form without forming gaps between adjacent glass plates while the stacked glass plates are separable; the stacked glass plates are cut off in a circular shape or a doughnut-like shape in a block; and then, the processed glass plates are separated. According to this method, tipping which may result when glass plates are processed individually can be prevented whereby processing is easy, and productivity is improved.

Abstract: A vacuum degassing method wherein a molten substance at an elevated temperature in a storage tank is sucked to a vacuum degassing vessel through an uprising pipe connecting the storage tank and the vacuum degassing vessel by maintaining the vacuum degassing vessel at a negative pressure, the molten substance is degassed and the degassed molten substance falls to a guiding duct through a downfalling pipe connecting the vacuum degassing vessel and the guiding duct characterized by that a first flow quantity of the molten substance rising in the uprising pipe is restrained and a second flow quantity thereof falling in the downfalling pipe is controlled thereby maintaining a quantity of the molten substance in the vacuum degassing vessel at a pertinent level.

Abstract: A method of grinding a plate-like material comprises supporting a plate-like material on a circular carrying member having a gear at its outer circumference, engaging the gear of the circular carrying member with first and second transferring means which oppose at a predetermined distance, grinding a surface of the plate-like material in a grinding unit placed at or near a transferring path which is formed between the first and second transferring means by moving the carrying member which is driven by the first and second transferring means, and moving the carrying member from the grinding unit by driving the first and second transferring means after the completion of the grinding operation.

Abstract: A method of electropolishing and grinding the both surfaces of a circular workpiece comprises polishing and grinding the both surfaces of a circular workpiece with a pair of grindingstones which are so arranged as to oppose the polishing/grinding surfaces, the body material of the polishing/grinding surface of the grindingstones being composed of an electric conductive material wherein the grindingstones are connected to the positive pole of a power source and an electrode located in the vicinity of the grindingstones is connected to the negative pole, and a voltage is applied across the positive and negative poles, whereby a dressing operation to the polishing/grinding surfaces is conducted by the electrolysis of the pair of grindingstones during the polishing and grinding operation.

Abstract: A vacuum degassing method wherein a molten substance at an elevated temperature in a storage tank is sucked to a vacuum degassing vessel through an uprising pipe connecting the storage tank and the vacuum degassing vessel by maintaining the vacuum degassing vessel at a negative pressure, the molten substance is degassed and the degassed molten substance falls to a guiding duct through a downfalling pipe connecting the vacuum degassing vessel and the guiding duct characterized by that a first flow quantity of the molten substance rising in the uprising pipe is restrained and a second flow quantity thereof falling in the downfalling pipe is controlled thereby maintaining a quantity of the molten substance in the vacuum degassing vessel at a pertinent level.