US3225910A

US3225910A - Getter devices with non-evaporated gettering material, for maintaining vacuum in electronic tubes

Info

Publication number: US3225910A
Application number: US102756A
Authority: US
Inventors: Porta Paolo Della
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-02-04
Filing date: 1961-04-13
Publication date: 1965-12-28
Anticipated expiration: 1982-12-28

Description

Dec. 28, 1965 P. DELLA PORTA 3,225,910

GETTER DEVICES WITH NON-EVAPORATED GETTERING MATERIAL, FOR MAINTAINING VACUUM IN ELECTRONIC TUBES Filed April 13, 1961 FIG.3

United States Patent Ofitice 3,225,910 Patented Dec. 28, 1965 3 225 910 GETTER DEVICES WITH NQN-EVAPORATED GET- TERIN G MATERIAL, FOR MAINTAINING VACU- UM IN ELECTRGNIC TUBES Paolo Della Port-a, Via Gallarate 215, Milan, Italy Filed Apr. 13, 1961, Ser. No. 102,756 3 Claims. (Cl. 206.4)

The object of this invention is to provide an improvement in getter devices with a non-evaporated gettering material, for keeping vacuum in electronic tubes; namely, in devices of the kind with non-evaporated gettering material in tabloid shape.

As distinguished from known evaporated getter devices, in which the gettering material is completely evaporated and is deposited in the shape of a film on the walls of the electronic tube, which film has the task of absorbing the gases developed in the electronic tube, with the nonevaporated getter the gettering material keeps its shape and absorbs the gases developed in the electronic tube through its surface exposed to said gases. Consequently, the effectiveness of the non-evaporated getter depends not only on its composition, but also on the magnitude of its surface exposed to the gases. The increase of the surface area of the gettering material, however, is hindered by the limitations existing for the space requirement in practical application of getter devices in electronic tubes.

It is an object of the present invention to improve getter devices with non-evaporated gettering material in tabloid shape, either circular or parallelepiped, to the effect of increasing the surface area exposed to gases, without increasing the space requirement of the device. That result is attained according to the invention by creating supports for the gettering material which leave said material exposed on both the larger faces of the tabloid.

In the accompanying drawing there are illustrated by way of example some embodiments of the present invention, as follows:

FIG. 1 is a longitudinal section of a circular getter device;

FIG. 2 is a longitudinal section of a tabloid getter de vice; and

FIG. 3 is a top plan view of a strip support for tabloid getter devices.

FIG. 1 shows a circular getter device in the shape of a disc 3, of mixed type; namely, containing within an external peripheral channel an evaporated gettering material 1 and at the centre of the disc a tabloid of non-evaporated gettering material 2. In the disc 3 there is provided at its centre, by means of punching, a central hole having the diameter of the tabloid of non-evaporated gettering material 2. The border 3' of such hole is bent back in such a way as to constitute an anchorage for the tabloid 2. The tabloid is directly pressed into the hole with such a thickness that its

surfaces

2, 2" are at lower level with respect to the corresponding parts 3" of the disc, in such a way and for the purpose that the tabloid should remain protected against impacts during stockage and transport.

It is apparent that whatever is the position of the getter device in the electronic tube, both surfaces of the tabloid 2 are exposed to the gases developed in said tube.

FIG. 2 shows a type of support for a tabloid of nonevaporated gettering material 2, contained between two

discs

4, 4" with

central bores

6 and 6 having diverging

inner borders

7 and 7, respectively, forming a seat for the correspondingly shaped border 8 of the tabloid 2. The tabloid 2 and the bores 6 and 6' are geometrically complementary in shape, the diverging borders 7 and 7' of the said bores conformally receiving the beveled border 8 of the tabloid 2. Both the larger surfaces of the tabloid remain exposed to the gases.

FIG. 3 shows a type of support constituted by a strip of metal gauze 5, or of expanded metal sheet, whereonto the tabloids of gettering material are pressed. The tabloids may have any shape, for instance, circular 2a, square 2b or rectangular 2c. Also in this case the two surfaces of the tabloids remain exposed to the gases, since the supporting wire gauze 5 does not form a substantial hindrance. This shape of the device according to FIG. 3 moreover has the advantage of permitting a considerable flexibility of the support and of permitting, therefore, the application thereof to the curved surfaces of the anode of the electron tube. The production of this device may be carried out with automatic machines wherein the wire gauze strip passes continuously under magazines which are loaded with tabloids or with powder of gettering material, and the tabloid or the powder is pressed directly onto the supporting wire gauze. Subsequently the strip is cut to the desired lengths for every individual getter device. In lieu of the tabloids of a certain thickness, applied on one side of the supporting wire gauze, it is possible, of course, also to apply two equal tabloids, having half thickness, contemporaneously at the two faces of the wire gauze. As a further embodiment of this concept, it is possible to apply the relatively thin tabloids on the two sides of a flexible support such as a perforated or expanded metal tape in such a way that the two tabloids that are contemporaneously pressed against the tape, at one side and at the other side thereof, join through the resulting interstices in the tape and thereby remain attached to the support.

What I claim is:

1. In a getter device for maintaining a vacuum in electronic tubes, the combination comprising a non-evaporable gettering means,

support means for said gettering means including a flat perforated metallic strip means,

said gettering means including a tabloid of compressed non-evaporable gettering material, said tabloid having a peripheral portion and oppositely disposed surface portions separated thereby,

said peripheral portion being formed integrally with said perforated metallic strip means through an interstice thereof,

each of said tabloid surface portions defining a surface area on one side of said support means whereby said tabloid is exposed to gases on both sides of said support means.

2. The invention defined in claim 1 wherein said flat perforated metallic strip means comprises a flexible strip of wire gauze.

3. The invention as defined in claim 1 wherein said flat perforated metallic strip means comprises a flexible strip of expanded metal.

References Cited by the Examiner UNITED STATES PATENTS 2,167,852 8/1939 Rose 313-174 2,404,803 7/ 1946 Stafford 206-0.4 X 2,499,197 2/ 1950 Posey 2060.4 X 2,547,200 4/1951 Dorgelo 313178 X FOREIGN PATENTS 552,868 1/1960 Belgium.

975,603 3/ 1951 France.

879,429 6/ 1953 Germany. 1,079,746 4/ 1960 Germany.

830,319 3/1960 Great Britain.

THERON E. CONDON, Primary Examiner.

ARTHUR GAUSS, EARLE J. DRUMMOND,

Examiners.

Claims

1. IN A GETTER DEVICE FOR MAINTAINING A VACUUM IN ELECTRONIC TUBES, THE COMBINATION COMPRISING A NON-EVAPORABLE GETTERING MEANS, SUPPORT MEANS FOR SAID GETTERING MEANS INCLUDING A FLAT PERFORATED METALLIC STRIP MEANS, SAID GETTERING MEANS INCLUDING A TABLOID OF COMPRESSED NON-EVAPORABLE GETTERING MATERIAL, SAID TABLOID HAVING A PERIPHERAL PORTION AND OPPOSITELY DISPOSED SURFACE PORTIONS SEPARATED THEREBY, SAID PERIPHERAL PORTION BEING FOMED INTEGRALLY WITH SAID PERFORATED METALLIC STRIP MEANS THROUGH AN INTERSTICE THEREOF, EACH OF SAID TABLOID SURFACE PORTIONS DEFINING A SURFACE AREA ON ONE SIDE OF SAID SUPPORT MEANS WHEREBY SAID TOBLOID IS EXPOSED TO GASES ON BOTH SIDES OF SAID SUPPORT MEANS.