Abstract: A vacuum degassing apparatus for molten glass is comprised of an uprising pipe, a vacuum degassing vessel, a downfalling pipe, an upstream side pit that supplies molten glass to the uprising pipe, and a downstream side pit that receives molten glass from the downfalling pipe. The vacuum degassing apparatus for molten glass is further comprised of a separating mechanism that separates a part of molten glass moving from the downfalling pipe to the downstream side pit, and a returning pipe that returns separated molten glass to the upstream side pit.

Abstract: A vacuum degassing apparatus having a throughput of at least 200 tons/day without causing problems such as a stagnation of molten glass flow in the molten glass flow path, an increment of flow rate of the molten glass flow in a local area, an excessive increment of pressure loss of the molten glass flow. A vacuum degassing apparatus comprises a vacuum degassing vessel, and an uprising pipe and a downfalling pipe which are connected with the vacuum degassing vessel, wherein the vacuum degassing vessel includes a wide portion for providing a molten glass flow path, and in the wide portion, the proportion W1/L1 of the breadth of molten glass flow path W1 to the length of molten glass flow path L1 is at least 0.

Abstract: A vacuum degassing apparatus for molten glass is comprised of an uprising pipe, a vacuum degassing vessel, a downfalling pipe, an upstream side pit that supplies molten glass to the uprising pipe, and a downstream side pit that receives molten glass from the downfalling pipe. The vacuum degassing apparatus for molten glass is further comprised of a separating mechanism that separates a part of molten glass moving from the downfalling pipe to the downstream side pit, and a returning pipe that returns separated molten glass to the upstream side pit.

Abstract: A vacuum degassing apparatus for molten glass is comprised of an uprising pipe, a vacuum degassing vessel, a downfalling pipe, an upstream side pit that supplies molten glass to the uprising pipe, and a downstream side pit that receives molten glass from the downfalling pipe. The vacuum degassing apparatus for molten glass is further comprised of a separating mechanism that separates a part of molten glass moving from the downfalling pipe to the downstream side pit, and a returning pipe that returns separated molten glass to the upstream side pit.

Abstract: A vacuum degassing apparatus for molten glass is comprised of an uprising pipe, a vacuum degassing vessel, a downfalling pipe, an upstream side pit that supplies molten glass to the uprising pipe, and a downstream side pit that receives molten glass from the downfalling pipe. The vacuum degassing apparatus for molten glass is further comprised of a separating mechanism that separates a part of molten glass moving from the downfalling pipe to the downstream side pit, and a returning pipe that returns separated molten glass to the upstream side pit.

Abstract: A vacuum degassing apparatus for molten glass is comprised of an uprising pipe, a vacuum degassing vessel, a downfalling pipe, an upstream side pit that supplies molten glass to the uprising pipe, and a downstream side pit that receives molten glass from the downfalling pipe. The vacuum degassing apparatus for molten glass is further comprised of a separating mechanism that separates a part of molten glass moving from the downfalling pipe to the downstream side pit, and a returning pipe that returns separated molten glass to the upstream side pit.

Abstract: The present invention provides a vacuum degassing apparatus and a vacuum degassing method for molten glass, which can suppress generation of bubbles on an interface between molten glass and a wall face of a conduit for molten glass such as a vacuum degassing vessel, an uprising pipe or a downfalling pipe that constitute a vacuum degassing apparatus, or influence of lowering of vacuum degassing effect due to rise of the level of molten glass in the vacuum degassing vessel, and which can stably exhibit the effect of vacuum degassing.

Abstract: The present invention is to provide a molten glass producing apparatus realizing simultaneously the production of a glass article of high quality and save-energy in producing molten glass, a molten glass producing method employing the molten glass producing apparatus and a method for producing a glass article. In the molten glass producing apparatus having a vacuum degassing apparatus, the melting tank is provided with a separating means for separating the area for circulating the molten glass in the melting tank into an upstream circulation flow and a downstream circulation flow, the distance from the separating means to the downstream end of the molten glass flow path in the melting tank is from 0.1 LE to 0.