US2590173A - Deionized electrode in electric glassworking - Google Patents

Description

March 25, 1952 GUYER 2,590,173

DEIONIZED ELECTRODE IN ELECTRIC GLASSWORKING Filed Feb. 9, 1948 E 7 i wn r51? 3 1 70 VA CUUM L075 T0 WA TEE SUPPLY ll/YE Zinhentur 450w) M Gu s? Qtinmep Patented Mar. 25, 1952 DEIONIZED ELECTRODE IN ELECTRIC GLASSWORKING Edwin M. Guyer, Corning, N. Y., assignor to Corning Glass Works, Corning, N. Y., a corporation of New York Application January 9, 1948, Serial No. 1,293

8 Claims.

The present invention relates to the working of hard glass bodies and more particularly to means and methods by which glass bodies arranged between suitable electrodes may be highly heated in localized regions by application of suitable power to the electrodes.

It has long been known to those skilled in the art that as the impressed voltage rises, it becomes increasingly easy to pass a current of electricity through glass. Even by the use of a high-frequency current, however, the application of sulficient power to heat a piece of glass requires a voltage such that flashover or wrap-around effect will ordinarily occur unless the glass has been preheated to a conductive temperature. The term fiashover is used in reference to current passing around a stationary article arranged between stationary electrodes, and wrap-around effect has reference to current passing about an article between electrodes. in an arrangement where there is relative movement between the electrodes and article.

Several arrangements for preventing fiashover and wrap-around effect in heating circuits employing high-frequency currents have heretofore been devised, some of which are fully described in Guyer Patent 2,306,054, granted December 22, 1942, and in Guyer Patent 2,422,482, granted June 17, 1947.

The primary objects of the present invention are means and methods suitable for the prevention of flashover or wrap-around effect even when employing potentials required to heat glass directly from a commercial frequency current source, so that the expense of equipment for converting such current to a high frequency can be avoided.

Other objects and features are the anchoring of arcs or ion flames formed between the electrodes and article to the areas immediately between the article and the electrodes, so that heat is introduced into the articleat exactly the desired places; to producearcs that have minimum destructive effect on the electrodes; to prevent volatile foreign matter freed in the arc area from entering the glass; and to effect de-ionization or partial removal of ionized atmosphere immediately adjacent the discharge path and quenching for the purpose of attaining maximum power control.

The accompanying drawing illustrates a typical arrangement embodying the invention.

Fig. 1 is a longitudinal sectional view of an electrode embodying the invention.

Fig. 2 is a diagrammatic view of an arrangement of novel circuits and apparatus, including Fig. 3 illustrates, in section, an alternative form of electrode embodying the invention.

The electrode in the particular form shown in Figs. 1 and 2 comprises a main body portion having a working end |2 in part surrounded by a sleeve 13 threaded to an enlarged portion H of body I I so as to form a cooling cavity |5 about the main body portion near its working end. Tubes l6 and H are passedthrough suitable apertures in portion M to enable a cooling medium such as water to be circulated through cavity |5, thus giving the electrode long life.

The body H has a bore passing through the axial center thereof and, opposite its working end, has a fitting 2| for coupling a vacuum line 22 into communication with the bore 20.

As illustrated in Fig. 2, two electrodes 3| and 32, having the features of the described electrode of Fig. l, are arranged on opposite sides of a piece of glassware 33 supported with its open end down in a suitable rotating vacuum chuck 34. The bores of electrodes 3| and 32 are connected to a vacuum line 35 via a suitable valve 36 so that the degree of vacuum may be adjusted as desired.

Melting current is supplied to the glass by electrodes 3| and 32 from a commercial current source via an adjustable direct current saturable reactor 40, a variable non-saturable alternating current reactor 4|, and a transformer 42.

In the operation of the above-described equipment the article 33, taken directly from the source of formation or alternatively preheated to a suitable temperature, is placed in chuck 34 and rotated between electrodes 3| and 32 so that such electrodes scan the article along the desired line of severance in the manner fully described in the above-cited patents. By suitable adjustment of reactors 40 and 4|, a potential suitable for melting the glass between electrodes 3| and 32 is supplied thereto. If the degree of vacuum is increased as the potential is raised, a potential can be applied which achieves rapid melting of the glass while the electrodes function to attain the various desirable objectives hereinbefore mentioned.

In some glassworking operations there may be objection to employing electrodes of the type disclosed in Fig. 1 because. in the use of this form of electrode, considerable heat and foreign matter may be drawn into the vacuum line. An electrode avoiding these possible objectionable features by having an injector embodied therein has accordingly been illustrated in Fig. 3. The electrode of Fig. 3 comprises a sleeve 55 surrounding a core 5| having a spiral groove 52 thereabout, the open side of which is closed by the sleeve. The end of groove 52 near the working end 53 of core 5| is connected through sleeve to a tube 54. The other end of groove 52 opens into the large end of a cone-shaped cavity within 'a. conical cap 56 whose large end is threaded onto example air and/or water or other coolant to tube 54, the necessary suction through tube 58 for proper operation of the electrode to prevent 'flashover or wrap-around effect is accordingly created by injector action. At the same time, proper cooling of the electrode is attained by the passage of the fluid through the spiral groove 52.

Although the invention has been herein illustrated and described as applied to a simple burnofi operation, it will be appreciated that the same may be advantageously employed in any electrical glassworking system wherein electrodes are employed to pass heating current into a glass body, whether said body is still hot from its heat of formation, is preheated preparatory to direction of current into the glass by the electrodes, or whether or not there is relative movement between the glass and electrodes. As will be further appreciated, the electrodes may also be used to advantage for directing current into glass, whether preheated or not, when such bodies have had applied thereto a conductive coating along the path to be heated as taught, for example, in

Guyer et al. Patent 2,389,360 and in Gray Patent 2,398,525. As a further alternative, the invention anticipates the use of the electrodes to seal articles of revolution together as disclosed in the cited Guyer Patent 2,422,482 and, if desired, use of a conductive coating on one of the two articles of revolution along a line adjoining the meeting edges of such articles to accelerate the start of the heating operation. As will be appreciated, when a conductive coatingis being dissipated, its volatile constituents enter the arcs or ion names. The air currents toward the working ends of the electrodes under these conditions are particularly helpful in removing this foreign matter from the arcs and thus prevent its entry into the glass. What is claimed is:

1. The method of working a hard glass body which comprises arranging that portion of the body to be heated in a path between two power input electrodes, applying electric power to such electrodes of a character suitable for establishing a, discharge for heating to softness that portion of the body arranged therebetween and of a voltage tending to create a discharge around rather than through the body and preventing the discharge from passing around the body by partial withdrawal of ionized atmosphere from between the body and electrodes. l

2. In an electrode suitable for introducing a current of electricity into a glass body, a member having a cylindrical core having a spiral groove thereabout, a sleeve tightly surrounding said core, said sleeve having a tubulation in communication with one end of said groove, and a cap for said sleeve tubulated to atmosphere and having a relatively large cavity therein with which the opposite end of said groove is in communication.

3. The method which comprises introducing electric current of suitable potential from a pair 'of electrodes into a heated glass article arranged therebetween, creating air currents from the article toward the working faces of the electrodes to effect partial removal of ionized atmosphere in directions toward such electrodes and increasing the intensity of the air currents as the power input is increased.

, 4. A method such as defined by claim 3 wherein creation of the air currents is effected by injector action. I

5. The method of effecting a sealing-together of two glass articles at meeting surfaces, which includes applying a readily dissipated conductive stripe on one of the articles along an edge of one of such surfaces, arranging the articles where they meet between two power input electrodes, applying sufficient power to dissipate the conductive coating to heat the glass in the area to be sealed to a more conductive temperature than that of the adjoining regions and thereafter increasing the power input to rapidly melt'the glass in the sealing region while removing volatile foreign matter from the power input areas by creating air currents toward the working ends of the electrodes.

6. The method of efiecting a sealing-together of two glass articles at meeting surfaces, which includes applying a readily dissipated conductive stripe'on one of the articles along an edge of one of such surfaces, arranging the articles where they meet between two power input electrodes, effecting relative movement between the articlesand the electrodes in such manner that the electrodes scan the whole length of the meeting surfaces, applying sufficient power to dissipate the conductive coating to heat the glass in the area to be sealed to a more conductive temperature than that of the adjoining regions and thereafter increasing the power input to rapidly melt the glass in the sealing region while both controlling the power input path and the removal of volatile foreign matter therefrom by creating air currents toward the working ends of the electrodes.

'7. The method of working a hard glass body which comprises locating that portion of a glass body to be heated in alignment with electrodes spaced therefrom but adjacent thereto, applying wards the electrodes. EDWIN M GUYER narassnons orrnn The following references are of record in the file 'of this patent: I

UNITED STATES PATENTS Number Name Date 685,717 Frolich Oct. 29, 1901 1,707,433 Hand Apr. 2, 1929 2,306,054 Guyer Dec. 22, 1942 2,307,749 Slepian Jan. 12, 1943 2,389,360 Guyer et al. Nov. 20, 1945 2,428,969 Guyer Oct. 14, 1947 2,445,063 Guyer July 13, 1948 2,473,258 Potter June 14, 1949 2,492,705 Mason Dec. 27, 1949 FOREIGN PATENTS Number Country Date 2,165 Great Britain 1913

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