US 3457448 A
Description (OCR text may contain errors)
July 22, 1969 F. P. SCOTT 3,457,448
QUICK FLASH HIGH YIELD GETTER WITH MEANS TO RESTRAIN WARPING AND BREAKING OF THE GETTER MATERIAL Filed July 22, 1966 ,13 WW H] oHQ G FIGZ 20 I2 I? mp 1 1 m INVENTOR FREDERICK P. SCOTT.
US. Cl. 313-174 Claims ABSTRACT OF THE DISCLOSURE Getter material is contained in an annular channel support having a radial dimension exceeding its depth, whereby a large surface area of the alloy is exposed. Annular means is fixed to the support and interlocked with the alloy below the exposed surface thereof to restrain the alloy from warping and buckling during sudden and high temperature rise.
In the evacuation of certain electronic tubes at the present time, it is desirable to employ a getter which will produce a very high yield in a short length of time. In order to obtain the high yield, a greater amount of getter material is used and is arranged so that a relatively large surface area of the material is exposed. In order to shorten the time required to flash the getter material, it is necessary to bring the getter material up to the flash tem perature in a short period of time. This requires the induction of greater current flow in the getter alloy.
In order to induce the high current flow in the getter alloy to more quickly raise the temperature thereof, the alloy is of annular formation being mounted in an annular support. In order to get maximum yield from the getter alloy in the shortest time period, the surface of the alloy is of maximum dimension. This means that the getter alloy is best in the form of a relatively thin washer.
To bring the getter alloy to the flash temperature in a short period of time, a substantial amount of heat must be quickly imparted to the alloy. This results in the alloy expanding rapidly in a circumferential direction, especially in the peripheral portion thereof. Due to the fact that the alloy is confined in the channel support, there is a warping, or buckling, of the expanding alloy. This warping, or buckling, is due, I believe, to the fact the coefficient of expansion of the alloy and support is not the same. In any event, when a portion of the alloy raises up, or separates, from the support, the area of the support not contacted by the alloy overheats and burns through with deposit of support material in the tube. Also, the buckled alloy frequently cracks, producing loose pieces of alloy which also may drop into the tube.
This invention has as an object an annular getter structure which, when the getter alloy is flashed, will prevent warping, or buckling, of the getter alloy in the suport. P More particularly, this invention has as an object a getter structure embodying means in the form of a retainer fixedly secured to the support and interlocked with the getter alloy, whereby the latter is prevented from warping, or buckling, prior to or during the flashing of the getter alloy.
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 drawings in which like characters designate corresponding parts in all the views.
United States Patent C) Patented July 22, 1969 ice FIGURE 1 is a top plan view of a getter structure embodying my invention.
FIGURE 2 is a sectional view taken on line 22, FIGURE 1.
FIGURES 3, 4 and 5 are cross sectional views, similar to FIGURE 2, showing modified channel support structures.
FIGURE 6 is a perspective view of a getter illustrating the warped condition of the alloy.
FIGURE 7 is a view taken on line 77, FIGURE 6.
The getter structure comprises an annular support, channel shaped in cross section, with inner and outer walls 10, 11, and a bottom wall 12. The spacing between the inner and outer walls 10, 11, is substantially greater than the depth of the channel. Getter alloy, indicated at 13, is impacted in the channel support.
FIGURE 6 illustrates the buckling of the alloy in getters of conventional construction. Usually a crack 14 oc- CBIS in the buckled portion 15 of the alloy. Often, there are a plurality of these cracks which, on occasion, extend across the radial dimension of the alloy, providing loose pieces of the alloy which fall free in the tube. The burn through in the support is shown at 17.
Annular reinforcing means is provided and interlocked with the getter alloy to maintain the same in co-planar form during the sudden and high temperature rise of the alloy.
Referring to FIGURES 1 and 2, the reinforcing means consists of a ring member 18 positioned on the bottom wall 12 of the support and dimensioned so that it is positioned closer to the outer wall 11 than the inner wall 10. Preferably, the reinforcing ring 18 is fixedly attached to the bottom wall 12, as by spot welding. The getter alloy 13 is impacted about the ring 18 and accordingly becomes interlocked therewith. The reinforcing member 18 serves to prevent the getter alloy from warping, or buckling, during the rapid temperature rise previous to the flashing of the alloy.
In FIGURES 3, 4 and 5, the reinforcing means is in the form of an annular bead formed integral with the support. In FIGURE 3, an internal head 20 is formed in the outer side wall of the support, or the bead may be of external form, as shown at 21 in FIGURE 5. In FIGURE 4, the head 22 is formed in the outer side wall 11 contiguous to the bottom wall 12 of the support.
The bead formation shown in FIGURES 3, 4 and 5, is particularly advantageous in that it does not require the handling of a separate piece during the formation of the getter. In all instances, the interlock between the getter alloy and the retaining means is effective to prevent any warping, or buckling, of the alloy during rapid heating thereof.
What I claim is:
1. A getter structure comprising an annular channel support, a quantity of getter alloy embedded in said support, an annular reinforcing means contained in said sup port and interlocked with said alloy.
2. A getter as set forth in claim 1, wherein said reinforcing means consists of an annular member of circular cross section fixedly secured to the inner surface of the bottom wall of said channel.
3. A getter as set forth in claim 1, wherein said reinforcing means is formed integral with said support.
4. A getter as set forth in claim 1, wherein said reinforcing means consists of a bead formed in the outer wall of said channel support and being spaced downwardly from the top edge thereof.
3,457,448 3 4 5. A getter as defined in claim 4, wherein said bead FOREIGN PATENTS is formed in the outer side Wall of said channel support 648 560 9/1962 Canada contiguous to the bottom wall thereof. 736:475 9/1955 Great Britain References Cited 5 JAMES W. LAWRENCE, Primary Examiner UNITED STATES PATENTS R. F. HOSSFELD, Assistant Examiner 2,465,597 3/1949 Marsh. 3,323,642 6/1967 Kost. U.S.C1.X.R. 1,425,790 8/1922 Moyer 206-.4 206-.4