US2316127A - Getter for vacuum tubes - Google Patents

Description

April 6, 1943. A.'J. KING I 2,316,127

GETTER FOR VACUUM TUBES Filed Dec. 8, 1941 ATTO NEYS.

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Patented Apr. 6, 1943 GETTER FOR VACUUM TUBES Aden J. King,

Laboratories tion of New York Syracuse, N. Y., assignor to King Inc., Syracuse, N. Y., a corpora- Application December 8, 1941 serial No; 422,079

' 2 Claims. (01. 2'50*-27'.5")

This invention relates to getters employed to' produce high vacuum in so-called vacuum tubes, and relates more particularly to the production of high vacuum in thermionic tubes, such as radio tubes and the like.

At the present time, these getters consist of a piece of metal to which is attached the getter material or medium, the piece of metal being supported within the glass envelope of the tube and after the tube has been exhausted by mechanical means and sealed, the metal getter is brought'to a high temperature by the application of high frequency currents. The metal is thus heated sufiiciently to vaporize the getter material whereupon the material functions to reduce any gas remaining in the tube.

The tubes referred to are manufactured in great volume production, most of the manufacturing process being carried out by automatic machinery. The application of the high frequency current is accomplished by inserting the completed envelope into a coil energized by such current. This heating of the metallic support for the getter material consumes an appreciable amount of energy and time. The getters in common use are usually formed of nickel inasmuch as this metal, in the shape and form now used, is more efiiciently heated to the desired temperature. However, the melting point of this material is too low to permit the use of certain getter materials which, in themselves, are more effective in producing the extremely high vacuum necessary for the proper operation of the tube.

This invention has as an object a getter or support for getter material so constructed and arranged that it will be more effectively and elliciently heated by the induced current from the high frequency coil resulting in an appreciable reduction in the power consumed in raising it to the required temperature to vaporize the getter material and also to reduce the time interval necessary for this operation and which has the further advantage that the support may be formed of materials other than nickel, such for example as iron or steel, without increasing the consumption of current in the heating process, and which materials are at the present time more available and at a substantial reduction in cost.

Tests conducted have proven that getters embodying my improved construction and formed of steel have more favorable power and time requirements than the conventional getters now formed of nickel or, if getters embodying my invention are made from nickel, there is a decrease of approximately forty percent in the power input required for heating, as compared with the present form of getter made of nickel. prefer however to construct the getters of steel as this will permit the use of more effective getter materials which, as explained, have not previously com into common use because of their high vaporization temperatures.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawing in which like characters designate corresponding parts in all the views.

Figure 1 is a view, in elevation, of a radio tube in'which a getter of my invention is mounted.

Figure 2 is a perspective view of a getter embodying my invention.

Figure 3 is a top plan view of the structure shown in Figure 2.

Figure 4 is a sectional view taken on line 44, Figure 3.

Figures 5, 6 and 7 are views similar to Figure 2 illustrating slight modifications of my invention.

Figure 8 is a sectional view taken on line 8-8, Figure 7.

Figure 9 is a top plan view illustrating another modification.

In accordance with my invention, the getter consists of a support in the form of a closed band Ill formed from thin sheet metal. The sheet metal, from which the band is formed, is relatively thin, being in the neighborhood of .005 to .010 of an inch in thickness, whereby the thickness A, Figure 4, is less than the width of the band indicated at B. This band may be of any desired shape, such as circular, elliptical, or rectangular.

The getter material or medium, indicated at H, is attached to the band in any suitable manner as for example forming a small depression or cut in the band and pressing the getter material therein. The band is provided with a support member in the nature of a rod l2 Welded or otherwise secured at one end to the band l0 and being fixedly secured at its opposite end to the supporting structure within the tube, as illustrated in Figure 1. The rod I2 is adopted to position the band with the axis thereof extending parallel to the axis of the tube.

In use, the current from the high frequency induction coil quickly heats the band to a temperature for vaporizing the getter material H. In order to heat the getter material I I more rapidly and with less power consumption, the band may be provided with a portion l3 of reduced cross sectional area. As shown in Figure 5, this area is produced by cutting away a portion of the band, or cutting a notch therein. In Figure 6, the band is cut away adjacent both side edges to form the reduced portion l3 and, in Figure 9, the band is partially formed by a thinner portion Hi, the portion l4 being only a fraction of the thickness of the material from which the main portion is formed. In each instance, the getter material H is arranged in or on the portion of reduced cross sectional area.

I prefer the structures shown in Figures 7 and I 8. The reduced area I3 is formed by a pair of spaced cuts extending inwardly from one side of the band, the material between the cuts however is not removed as in Figure 5, but is folded downwardly in the form of a flap or tab'l5 to prevent the spattering or loss of getter material and, at the same time, to direct the vaporized getter material toward the base of the tube and away from the metal elements in the upper part of the tube.

What I claim is:

1. An individually fiashable vacuum tube getter comprising a closed band open at each end and formed from thin sheet metal and being of greater width than thickness in cross section, said band having a portion of reduced cross sectional area and a quantity of getter material attached to the reduced portion of said band.

2. An individually flashable vacuum tube getter comprising a closed band open at each end and formed from thin sheet material and being of greater width than thickness in cross section, said band being cut from one edge inwardly at spaced intervals to form a tab, said tab being bent out of the plane of the band to form a portiono-f the band of reduced cross sectional area, a quantity of getter material attached to the reduced portion of said band and said integral Jtab being folded over said material.

- ADEN J'. KING.

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