Owens-illinois, Inc.

Philip D Perry

Marvin L Barkhau

James E Sherman

Daniel S Farkas

Emery J Hornyak, Jr

Roland F Pimm

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

Molten glass entering from a refiner is conditioned, in an optimum operation, such that its temperature along the center of the flowing glass just in advance of its entry into the feeder, will be of equal temperature near the surface near the bottom and intermediate these two points. A tri-level thermocouple is positioned along the center line at approximately nine inches from the feeder for monitoring these temperatures, and to serve as an aid to the operator in controlling the actual glass temperature. Positioned at opposite sides of the forehearth, approximately eight inches from the center line, are tri-level thermocouples. The three couples will be positioned at the same relative depths as those at the center line. The center thermocouple on the right side will have its output used as the control temperature for a temperature override circuit connected to the electrodes. The temperature override circuit will have a set-point temperature indicator whose level is selected by the operator and this selected level is compared to the output of the middle side electrode. Typically, the operator will select the set-point temperature to be that temperature which it is desired to achieve relative to the center line thermocouple temperature indicators. Ideally, all of these temperatures will be in agreement and the temperature of the glass will then be that at which optimum working properties of the glass will be attained.

Electric boosting control for a glass forehearth

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.

Electric forehearth and method of melting therein

A glassware forming machine including means for distributing gobs of molten glass to individual sections of the machine at a predetermined rate, drive means responsive to electrical power of a selected frequency generated by a power source for driving the gob distributing means at the predetermined rate and an automatic control means responsive to timing signals for controlling each of the individual sections in a predetermined timed sequence of steps for forming the glassware wherein the power source generates the timing signals at a frequency proportional to the selected frequency of the power source. Each piece of glassware is formed during a machine cycle which is related in duration to the gob distribution rate and typically is defined in terms of 360.degree.. The power source includes a timing pulse generator which synthesizes the timing signals from the power source electric power frequency at the frequency required for defining 360.degree. per machine cycle.

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Toledo, OH, United States of America

Philip D Perry