GB337431A - An improved process and apparatus for producing glass vacuum-insulated vessels - Google Patents

Abstract

337,431. Aladdin Industries, Ltd., (Assignees of Davis, C. W., and Becker, F. F.). Oct. 29, 1928, [Convention date]. Forming hollow - walled vessels.-A method of producing a vacuum flask consists in assembling two blanks, each having a closed bottom, one within the other, heating the free end of the outer blank until it is plastic, rotating the blanks, and applying pressure to the softened glass to form a neck, and then applying pressure to the adjacent edges of the two blanks to bring them into contact so that they weld and form a rim at the mouth of the flask. The flask consists of an outer blank 1, Fig. 4, and an inner blank 2 united at their necks and separated, as usual, by spacers 8 of asbestos or other suitable material. A narrow ridge or seating 7 is formed at the top of the outer blank to receive the inturned edge of the protective casing. The neck is also flared outwards slightly so that it is supported by the casing. A machine for making the flask comprises vertical shaft 41, Fig. 5, which carries at its lower end a hollow chuck 33 and is rotated at a high speed by a driving-shaft 34. Another vertical shaft, 42, is arranged in line with the shaft 41 and is movable vertically. This shaft carries at its upper end a rotary cap 43 and a spacer 42<a>, Fig. 3, for supporting the inner blank, as shown, while the outer blank of an assembled pair is held in the chuck 33. The machine also includes four shaping-rollers 9 - - 12. The rollers 9, 11 are trebly rotatable on pins which are carried by an arm 27a secured, to the upper end of a vertical shaft 27. This shaft is oscillated by a cam 22a in order to bring the rollers 9 and 11 in turn into contact with the flask. It is moved vertically by a cam 22<b> during the shaping of the neck of the flask. The rollers 10, 12 are carried at the upper ends of vertical rods 28, 31, respectively, which are moved vertically by cams 30<a>, 30<b>. Other cams 23a, 23<b> are used to swing the roller 10 and a gas burner X in an horizontal direction. In making a flask, an inner blank is placed in an outer blank with the spacers 8 in position, and the assembly is supported by the rod 42 and the chuck 33 and rotated. The speed of rotation is such that the glass, when plastic, is forced by centrifugal force into contact with the shaping- rollers. The shaft on which the cams 22, 23, 30 are mounted is clutched to the driving-shaft, and the burner X is swung inwards so that its flames play on the lower parts of the blanks. When the lower part of the outer blank is softened, the conical roller 9 moves into contact with the glass and forces it inwards gradually until the edges of the two blanks are close to one another, and these edges are forced into contact with one another by the roller 10, or a hand tool, until they are welded. The roller 9 is then replaced by a roller 11 which shapes the outer blank to form a neck, as shown in Fig. 3. The roller 12 is also moved vertically against the welded rim and forms the ridge 7.