US1199487A - Seal. - Google Patents

Description

" H. A. NEWCOMB.

SEAL.

APPLICATION FILED AUG.6,19i5- 1 ,1 99,487. Patented Sept. 26, 1916.

WiTNESSES:

" flaw/a A Wen (002k lNVENTOR- UNITED STATES PATENT OFFICE.

HAROLD A. NEWCOMB, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECT-RIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYL-,.

VANIA.

SEAL.

Specification of Letters Patent.

Application filed August 6, 1915. Serial No. 43,979.

To all whom it may concern:

lie it known that I, HAROLD A. NEwCoMB, a citizen of the United States, and a resident of Wilkinsburg,.in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Seals, of which the following is a specification.

Myinvention relates to sealing structures for the leading-in conductors of vapor electric apparatus, such, for example, as vapor converters of the glass-container type, and it has for its object to provide a structure of the character indicated that shall be simple and inexpensive in manufacture and extremely rugged in operation.

In the accompanying drawings, Figure 1 is a side view, partially in section and partially in elevation, of a vapor-converter bulb embodying the preferred form of my invention; Fig. 2 is an enlarged view, par tially in section and partially in elevation, of one of the anodes embodied in the bulb of Fig. 1, together with its attendant sealing structure; and Fig. 3 is a sectional view of the structure shown in Fig. 2, taken on the plane IIIIII.

In the manufactum of vapor-electric apparatus, such, for example, as vapor converters, it is essential that relatively largeamounts of electrical energy be conducted through the walls of exhausted glass containers by means of joints which shall be simple and inexpensive in manufacture" and which shall remain gas-tight throughout long periods of time. For many years, platinum was employed forleading-in conductors of the character described, forming an exceptionally tight and effective seal with the ordinary soft glasses. lVith the growth of the art, however, it has been found necessary to employ refractory low-expansion glasses and, not only is platinum unsuited for containers of this character, on account of its relatively high coefficient of expansion, but its price is almost prohibitive for seals of large current-carrying capacity. It has, therefore, been proposed to employ tungsten for leading in conductors in conjunction with containers formed of refractory glass of the sodium boro-silicate character, as described and claimed in my copending application, serial No. 811, filed Jan. 6, 1915, and assigned to the lrVestinghouse Electric 8c Manufacturing Company.

lVith all seals of the character described, it is necessary that the glass be flared away from the leading-in conductor in order to ]O1I1 the container wall, and this point of flare or divergence is generally the point of failure of the seal because of the concentration of stresses thereat arising from divergencies in the coefiicients of expansion of the glass and metal and from mechanical blows encountered by the electrode leads. I have found that, by embedding a ring of material having high tensile strength and preferably composed of the same material as the leading-in wire in the glass at the point of flare, a seal may be produced which is highly resistant to mechanical and thermal injury.

Referring to the accompanying drawing for a more detailed understanding of my invention, I show the bulb of a vapor converter, preferably composed of sodium borosilicate glass, at 4. The bulb 4 is provided with an anode 5 and with other suitable electrodes, as desired. The anode 5, as shown in Fig. 2, is mounted on the end of a stem 6 composed of conducting material, such, for example, as tungsten. A mass of sodium-boro-silicate glass 7 is sealed to the stem 6 and is joined to a flare or bell 8 of like material at a point 9. The flare 8 is sealed to the container wall in the usual manner, as shown at 10 in Fig. 1.

In the manufacture andoperation of a vapor converter, the point 9 is generally the seat of seal failure, onaccount of the concentration of stresses thereat, and I have found that, by embedding a ring 11, preferably composed of tungsten, in the mass 7 adjacent the point 9, the strength of the seal may be greatly increased. The ring 11 may be nearly in contact with the stem 6 or it may have such a diameter as to locate it nearer the outer surface of the mass 7, if desired.

In operation, the tungsten has a linear coefficient slightly in excess of that of the glass. Consequently, in cooling a new seal, the material of the wire 11 is placed in tension and the stem 6 tends to draw away from the mass 7. It results, therefore, that the strain placed upon the mass 7 at the point 9 is in part compensated for by compression placed thereupon by the ring 11. The glass is thus maintained in a more or less neutral state and is not liable to rupture.

While I have shown my invention in its preferred form, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various minor changes and modifications within the scope of the appended claims.

I claim as my invention:

1. In a seal for vacuum apparatus, the combination with a linear conducting member, of a mass of vitreous material surround-. ing and fused to said conducting member, a flaring bell of vitreous material fused to said mass, and a ring of material having high tensile strength surrounding said conductor and embedded in said mass adjacent the point of attachment of said bell.

2. In a seal for vacuum apparatus, the combination with a linear conducting member, of a mass of vitreous material surrounding and fused to said conducting member and formed into a bell flaring outwardly therefrom, and a ring of material having high tensile strength surrounding said conductor and embedded in said mass near the point where it diverges from said conductor.

mg and fused to said conducting member and formed into a bell flaring outwardly.

therefrom, and a ring of material having high tensile strength and a like coefficient of expansion to that of said conductor surrounding said conductor and embedded in said mass near the point where it diverges from said conductor.

4. In a seal for vacuum apparatus, the combination with a linear conducting member, of a mass of vitreous material having a slightly lower coefficient of expansion surrounding and fused thereto, said mass flaring outwardly from said' member, and a ring of material having a like coeflicient to said linear member surrounding the same and embedded in said mass adjacen its point of divergence from said conductor.

In testimony whereof, I have hereunto subscribed my name this 21st day of July, 1915.

HAROLD A. NEWCOMB.

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