Asahi Glass Company, Limited

Misao Okada

Yusuke Takei

Toshiyasu Kawaguchi

Koji Obayashi

Hajime Itoh

Kazuhiko Ishimura

Rei Kitamura

Mitsuyoshi Sakai

Fumiaki Saito

Masaaki Yoshikawa

Keito Sekine

Shinsuke Nakajima

A process for producing a glass for cathode ray tubes, having a SbOcontent of from 0 to 0.19% as represented by mass percentage and containing HO, which process comprises a step of melting a raw material in an atmosphere under a pressure of Pto obtain a molten glass, and a step of vacuum degassing the molten glass in an atmosphere under a pressure Pwhich is lower than P, wherein the pressure P of the molten glass is made to be at most (6.1 W+0.06) atm in the vacuum degassing step, wherein W is the content of said HO as represented by mass percentage.

Process for producing a glass for cathode ray tubes

When molten glass which is under an atmosphere of pressure P, is fed into a vacuum chamber capable of rendering a pressure to the molten glass to be in a range of 38 &lsqb;mmHg&rsqb;-(P-50) &lsqb;mmHg&rsqb; to perform degassing to the molten glass, a staying time of the molten glass in the vacuum chamber is in a range of 0.12-4.8 hours, whereby there is obtainable an effective degassing function to the molten glass.

Vacuum degassing method for molten glass flow

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.

Vacuum degassing method and its apparatus

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Yokohama, Japan

Misao Okada