GLASS MELT PRODUCTION DEVICE, GLASS MELT PRODUCTION METHOD, GLASS ARTICLE PRODUCTION DEVICE, AND GLASS ARTICLE PRODUCTION METHOD

A glass melt production apparatus, which comprises a melting vessel, a vacuum degassing apparatus, a first conducting pipe structure connecting the melting vessel and the vacuum degassing apparatus, and a second conducting pipe structure to introduce a glass melt to a forming means, provided downstream the vacuum degassing apparatus; the vacuum degassing apparatus having an uprising pipe through which the glass melt from the melting vessel ascends, a vacuum degassing vessel, and a downfalling pipe through which the glass melt from the vacuum degassing vessel descends; the flow path of the glass melt in the uprising pipe, the vacuum degassing vessel and the downfalling pipe being made of a refractory material; the first conducting pipe structure having an upstream pit to supply the glass melt to the uprising pipe; and the second conducting pipe structure having a downstream pit containing the glass melt from the downfalling pipe; the glass melt production apparatus further comprising a third conducting pipe structure connecting the upstream pit and the downstream pit; and the third conducting pipe structure having a closing means to shut off a flow of the glass melt in the third conducting pipe structure; the third conducting pipe structure or the closing means having a glass melt flow path for emergencies, which allows the glass melt to pass therethrough, depending on the height of a liquid level of the glass melt in the third conducting pipe structure in the vicinity of the closing means.