Device for electrically grounding a float glass production apparatus

Abstract

A float glass apparatus typically includes a float tank for a metal bath, the metal bath, a glass melt producing unit, which includes a melting tank for making a glass melt and a refining, tank for degassing the glass melt, and conducting devices for conducting the glass melt from the glass melt producing unit to the metal bath of the float tank and auxiliary devices as needed. In order to minimize bubble defects and extend service life of Pt units by a suitable electrical device the float tank with the metal bath is connected electrically with ground and at least one auxiliary electrode is connected with ground and put in electrical contact with the glass melt in the melting tank.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a device for electrically grounding a float glass production apparatus comprising a float tank with a metal bath; a glass melt producing unit, which comprises a melting tank for making the glass melt and a refining tank for degassing the glass melt; conducting devices for conducting the glass melt from the glass melt producing unit to the metal bath in the float tank and, as required, auxiliary units. [0003] 2. Related Art [0004] The production of float glass, especially of special glass, occurs in a so-called flat glass production apparatus of flat glass plant. The term “float glass production apparatus or plant” in the sense of the present invention means the entire apparatus of a typical structure, i.e. a production unit, which includes the entire hot region from the melting tank and refining tank up to the float bath upstream of the annealing system. Since the hot glass is a good...

AI Technical Summary

Benefits of technology

[0014] The essential prerequisite for occurrence of direct current flow with disadvantageous effects is the existence of a sufficiently low-resistance connection between at least two potential electrodes. This sort of connection is realized intentionally or unintentionally by a so-called ground connection in the daily production routine.

[0015] Intentional ground conditions are frequently closely connected with regulations for guaranteeing personal safety. They replace laborious or elaborate safety measures for routine handling. Likewise frequently ground-free construction of an apparatus means an expensive selection of materials during design or it simply is not a useful solution.

[0016] If the principle of ground-free construction is not part of the specifications of the apparatus, there are consequences. Once built up, many ground connections may not be undone with reasonable effort or expense.

[0017] The most important example here is the tin bath in the float tank, whose subsequent ground disconnection is not possible. Generally the liquid tin in the completely hot region remains the single direct connection to ground, but all would still be in order from an electrochemical viewpoint, when the current circuit is not closed on account of the absent second and further ground connections.

[0018] However other grounds may exist based on that. The supply apparatus, the overflow and the burners in the melting tank come into question. Subsequent ground disconnection is indeed possible in principle but only with a great effort or expense. The electrical contact here occurs by means of the furnace atmosphere, i.e. an actual ground circuit formed is high resistance. Typically also the ground is not definitely localized and it is characterized as a virtual ground.

[0019] Usually all measuring units (thermocouple elements, glass level meters), viewing closures, stirrers and all components at the interface, which are made of platinum or its alloys with other noble metals, are built-in without grounding without further effort.

Problems solved by technology

A reduction of the concentration difference is thus not possible.

The essential prerequisite for occurrence of direct current flow with disadvantageous effects is the existence of a sufficiently low-resistance connection between at least two potential electrodes.

They replace laborious or elaborate safety measures for routine handling.

Likewise frequently ground-free construction of an apparatus means an expensive selection of materials during design or it simply is not a useful solution.

Once built up, many ground connections may not be undone with reasonable effort or expense.

The most important example here is the tin bath in the float tank, whose subsequent ground disconnection is not possible.

Subsequent ground disconnection is indeed possible in principle but only with a great effort or expense.

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