The Viscosity and Working Characteristics of Glasses. Part V. Temperature Measurements during the Manipulation of Glass by Semi-Automatic Presses

JSGT 1945 V29 T233-T249

Temperature measurements both on the glass and on the mould. Parts were made during the manipulation by semi-automatic machines of five pressed objects of colourless glass, varying in weight from 9 oz to 58 oz. The mean range of viscosity values of the glass (in poises), at the different stages of manipulation as carried out in an individual factory, were found to be as follows: Gathering, 1200 to 2200; entry into the press mould, 2000 to 5000; commencement of pressing, 3000 to 6000; completion of pressing, 10^4·7 to 10^6·0; and at the removal from the mould 10^5·9 to 10^7·1. These viscosities are slightly lower than those noted in the corresponding stages of hand and automatic manipulation of glass, mainly by blowing processes, as quoted in Parts III and IV; a fact due, in these pressing processes, to working at somewhat higher temperatures. Some measurements of temperature at different parts of the moulds employed were also made. Finally, an attempt has been made to draw up a heat balance between the glass and the mould.

James Boow & W. E. S. Turner