Owens-illinois, Inc.

James E Sherman

Philip D Perry

Marvin L Barkhau

Emery J Hornyak, Jr

Donald H Poundstone

A conditioning section of a forehearth is disclosed with sidewall electrodes for Joule effect heating of glass positioned and connected to confine the current and Joule effect heating separately to the side portions of the molten glass flow path therein. Separate circuits, controls, temperature sensors and temperature set point control means are provided for the sidewall electrodes on each side. Glass temperature across the flow path is controlled and can be adjusted by separately controlling the flow of Joule effect current along each side of the flow path through manual or automatic, thermally actuated, controls for each side.

Electrically heated forehearth and method of controlling molten glass

A mold assembly and method for automatically making crown bottom blown glassware wherein a charge of molten glass is shaped into a hollow preform in a parison mold by means of a plunger. The hollow preform or parison is removed from the parison mold and placed in a finishing mold having a bottom forming assembly comprised of an annular member slidably contained in the bottom end of the finish mold and a domed central member slidably mounted in the annular member such that it can be reciprocated from a normally retracted position level with or slightly below the top surface of the annular member to a position above that surface. The hollow preform is allowed to sag into partial contact with the surfaces of both the retracted domed member and the annular member at which time the central member is advanced upwardly in the annular member so its domed position is above the top surface of the annular member, and then both plate members are advanced upwardly into full contact with the preform while the preform is blown into its finished shape.

Two-piece bottom plate for making crown bottom glassware on the HE-28

Disclosed is a method and apparatus for preventing the formation of blisters in an electrically-heated forehearth that utilizes submerged electrodes connected to either a single or plural phase alternating current source. The electrodes are arranged so that Joule effect heating is effected by passing alternating current through the molten glass with the center tap of the secondary of the power transformer being connected to the positive side of a Direct Current source through a filter, while the negative side of the DC source is connected to a counter electrode, immersed in the glass at a point upstream of the forehearth. With this physical arrangement, the formation of blisters due to free electrons migrating to and collecting on some of the electrodes that are at different potentials than the others is prevented. This is accomplished by the fact that all of the forehearth electrodes are maintained at the same potential and the counter electrode is at a different potential so that these free electrons will collect at the single counter electrode and create bubbles or blisters at a position well in advance of the forehearth. With this system, the blisters will disappear before reaching the forehearth. The forehearth electrodes are disclosed as being formed of stainless steel with molybdenum tips and the electrode support being electrically isolated from the forehearth structure.

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Temperance, MI, United States of America

James E Sherman