US1978423A

US1978423A - High power demountable tube

Info

Publication number: US1978423A
Authority: US
Inventors: Louis A Gebhard
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-03-14
Filing date: 1933-03-14
Publication date: 1934-10-30
Anticipated expiration: 1951-10-30

Description

Oct. 30, 1934. L. A. GEBHARD HIGH POWER DEMOUNTABLE TUBE Filed March 14, 1933 2 Sheets-Sheet 1 6 INVENTOR. QOM/io 61 mfilaw,

ATTORNEY Oct. 30, 1934. L. A. GEBHARD HIGH POWER DEMOUNTABLE 'lUBE Filed Marbh 14, 1933 2 Sheets-Sheet 2 INVENTOR. QmM/J 6L Bdfmd,

ATTORNEY I I I I. I. l w

Patented Oct. 30, 1934 "UNITED STATES PATENT OFFICE (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) My invention relates broadly to high power electron tubes and more particularly to a sym metrical construction of demountable electron tube.

One of the objects of my inventionis to provide a construction of high power demountable electron tube suitable for operation in pushpull symmetrical amplification circuits.

Another object of my invention is to provide a construction of high power demountable electron tube wherein the anode and control grid elements of two electron tube systems may be assembled in a demountable manner in compact relation, the anodes forming envelopes for the tube which may be continuously exhausted for maintaining that degree of vacuum required for operation of the electron tube systems.

Still another object of my invention is to provide a construction of double electron tube'suitable for operation in push-pull symmetrical circuits in which anode and control grid electrodes are concentrically mounted with removable insulation means for maintaining the electrodes. in position in cooperative relation to a replaceable cathode element supported between removable end members assembled with relation to the other elementso-f the tube electrodes.

A further object of my invention is to provide a construction of high power double electron tube having fluid cooled anodes which are assembled in concentric relation with respect to control grids and a replaceable cathode element, the anodes forming, with insulation members and end plates, a closedvessel subject to evacuation for maintaining that degreeof vacuum within the vessel required for proper functioning of the electron tube. i 7

Other and further objects of my invention reside in the construction and assembly of coacting parts for a double electron tube as set forth more fully in the specification hereinafter following by reference to the accompanying drawings, in which;

Figure 1 is a side elevation of a double electron tube with the anodes broken away and illustrated in cross-sectionand showing the control grids and cathode in side elevation; Fig. 2 is a vertical sectional view taken through the double electron tube of my invention; Fig. 3 is a plan view of the double electron tube of my invention; Fig. 4 is a transverse sectional view taken on line 44 of Fig. 2; Fig. 5 is a transverse sectional view taken on line 5-5 of Fig. 2; Fig. 6 is a fragmentary view illustrating the two aligned control grids and the insulated bushing which is disposed therebetween; Figs. 7, 8 and 9 illustrate modified forms of packings which may be employed for effecting a tight seal for the electron tube of my invention; and Fig. 10 shows a modified form of retaining means employed for maintaining the end plates in alignment with the insulation members forming part of the double electron tube of my invention.

The double electron tubeof my invention has been developed with aview of meeting economic requirements in high power electron tube transmitters. The discarding of a high power tube structure, after a relatively short term of life, results in great expense. The attempt at renew ing the cathode in the ordinary type of high power tube introduces many difliculties-and often produces economic waste. Thetube of my invention comprises parts which are readily assembled in demountable arrangement permitting the replacement of defective parts, particu larly a burned out cathode. The structure of my invention provides for the compact assembly of separate tube systems, each of which include a fluid cooled anode in coacting relation with a concentrically mounted control gridanda replaceable cathode. The anodes and control grids are each spaced by insulation members. 1 Insulation members are provided on the ends of the anodes against which end plates are assembled and means are provided for maintaining the end plates in position aligned'with the insulation members on the ends of the anodes. Various types of joints are provided for preventing the seepage of air into the chamber'formed by the anodes. The chamber is evacuated at such times as is necessary for maintaining the required vacuum within the electron tube. I provide special means for centering the control grids with respect to the anodes. A special contact arrange-' ment is provided for establishing connection between one of the control grids and the associated control'grid terminal carried by one of the end plates. In the event of deterioration of r electron tube.

Mountings

4 and 4 are supported by the end plates 5 and 5' of the tube. The filament terminals are shown at 6 and 6 connected to the end plates. The filament is positioned axially through the tube. One filament suffices for the two halves of the tube. In a push-pull circuit, the radio frequency current between anode and grid to the filament which normally has to pass through by-pass condensers is, in this arrangement, carried between the two halves of the filament. The only radio frequency current that the filament terminals are required to carry is the unbalanced component in the neutral lead. Another advantage of the arrangement of the filament is that there is a very short electrical path between the two halves of the tube. In the ordinary push-pull circuit using separate tubes, there is quite a length of lead through the bypass condensers from filament to filament, where it is necessary to introduce plate meters for each tube in negative return lead.

The

grids

2 and 2 are supported from

end plates

5 and 5 in a manner similar to the disclosure in my application Serial No. 660,707 filed March 14, 1933, entitled Demountable electron tube. The grids are insulated from each other by centrally arranged insulator bushing 7 which also serves to align the grid structures with respect to the other parts of the tube. The bushing 7 and other insulated parts of the tube are constructed from suitable insulating material such as magnesium silicate or magnesium and aluminum silicates. The control grid terminals are shown at 2a and 2a and are insulated by suitable bushing members from end plates 5 and 5'.

The anodes are each arranged for liquid cooling. Tubular members 8 and 8' form jackets 9 and 9' through which cooling liquid is passed. The inlets 10 and 10' are adjacent to the joints between the anodes and

insulators

11, 11 and 12 which support them. This arrangement, together with resilient gaskets 14 and 14' insures the tightness of the joints.

It will be appreciated that various forms of joints may be provided to prevent leakage of air into the chamber within the tube as illustrated for example in Figs. '7, 8 and 9.

Throughout the several assembly views of the tube of my invention, I have illustrated gaskets at each of the joints which are placed under compression for preventing the leakage of gas. To simplify the illustration of the invention, these gaskets have been illustrated schematically in the assembly views. However; I desire that it be understood that in practice the joints are formed with coacting faces establishing a serpentine course through the joint which substantially prevents undesirable leakage and provides a gas tight seal. Fig. '7 shows end plate 5 provided with an annular projection 5a which fits into a coacting annular recess 11a in the insulator 11. The gasket 14 which is disposed therebetween provides a substantial seal against the leakage i The insulator 11 is provided with a coacting face which is offset in steps or echelon formation as represented at lid. The gasket 14, disposed between the echelon faces 5d and 11d, serves to prevent seepage of gas between the joints. As I have pointed out, any one of the types of joint illustrated, or any other form of joint may be used for insuring a gas tight closure within the anode structure.

It will also be understood that the tension members 15 have been illustrated schematically for the purpose of simplifying the illustration and that in practice I employ any suitable arrangement of tension adjusting means for compressing the

end plates

5 and 5 against the gaskets 14, gaskets l4, insulator l1 and insulator 11, and against the

anodes

8 and 8. One form of tension adjusting means has been illustrated in Fig. 10.

Rod 20 of insulation material extends through the heads 5 and 5' provided with means thereon for drawing the heads together over

insulators

11, 12, and 11 with respect to

anodes

8 and 8. The insulated rod 20 has a metallic head 21 riveted thereon at one end to engage end plate 5. At the other end of the insulated rod 20, there is a sleeve 22 riveted thereto and externally screw threaded to receive a thumb screw 23 which is screwed against the top of the end plate 5. The tension member is preferably of insulation material to avoid capacity effects between the anode structures and between the cathode and the anode. In lieu of the tie rod construction, I may employ various forms of turnbuckle constructions or other arrangements of tension members. The

outlets

13 and 13 are located centrally with respect to the ends of each of the anodes. As shown in Fig. 1, the parts of the tube are maintained in assembled relation by longitudinal tension insulators 15 and nuts 16. Anode terminals are shown at 1'7 and 17. A connection for the exhaust pump is shown at 18.

The center part of the grid structure is shown more clearly and in more complete detail in Fig. 6. The grid support rings 19 and 19 slip over shoulders on the insulating member '7 which insures alignment of the grid structure. The insulating member 7 is telescopically disposed centrally within rings 19 and 19' carried by the supports for the

grids

2 and 2 for providing a rigid structure. Despite the rigidity of the structure, the control grids may be readily d'sassembled or assembled. This structure of the bushing 7 allows ready assembly of the tube in that the grids may be permanently fastened to their respective end plates and then inserted in the tube with insulated bushing 7 between them.

When the tube is assembled, the control grids 2 and 2' are centered concentrically with respect to anode 8 and anode 8' and, at the same time that electrical connection is maintained to terminals 2a and 2a. The aperture 5c in the end of end plate 5 is sufficiently large to permit the proper securing of the cathode l in the socket which connects to mounting 4 by means of a tool insertable through the aperture 5e.

By reason of the short electrical paths in the tube of my invention, it is possible to operate at a considerably higher frequency than is possible with a separate pair of ordinary tubes. The connections as they come from the tube lend themselves readily to symmetrical circuit design so essential for proper operation of a push-pull system.

I have described my invention in certain preferred embodiments but I desire that my inven- 11,978,423 tion be considered entirely in the illustrative sense, asI am fully aware that :many modifications in the structure of the tube of my invention may be made by those skilled inthe art, and I intend no limitations upon my invention other than are imposed by the scope of the appended claims.

I The inventionherein described maybe manufactur'ed and used by or.- for the Govermentof the United States of Amerioafor governmental purposes without the payment of any royalty thereon or therefor.

' What I claim 'as new and desire to secure by Letters Patent of the United States is as follows:

1. A demountableelectron tube comprising a bers for said control grids carried by the respective end plates.

2. A high 'power'tube' comprising a pair of cylindrical anodes, an insulating sleeve disposed intermediate said anodes, an insulating sleeve disposed over the ends of said anodes, end plates extending laterally across said last mentioned insulating means for securing said end plates under compression for providing a substantially closed" chamber defined by said insulatingsleeves and by said anodes, a-replaceable filament supported between said end plates, a control grid supported by each ofsaid'end plates, and means for insulatingly connecting said control grids at the adjacent ends thereof. i

3. A high. power tube comprising a pair of cylindrical anodes, an insulating sleeve disposed intermediate said anodes, an insulating sleeve disposed over the ends of said anodes, end plates extending laterally across said last mentioned insulating means for securing said end plates under compression for providing a substantially closed chamber defined by said insulating sleeves and by said anodes, a replaceable filament supported between said end plates, a control grid supported by each of said end plates, an insulating bushing telescopically engaging adjacent ends of said con- 1 trol grids for centering said control grids concentrically Within said chamber in spaced relation with respect to said filament and said anodes.

4. A demountable electron tube comprising a pair of cylindrical anodes, said cylindrical anodes j each having a shoulder on opposite ends thereof,

1 tending laterally with respect to said last mentioned sleeves, means interconnecting said end plates for maintaining said end plates in position with respect tosaid anodes and said sleeves for providing a substantially closed chamber, means for supporting a replaceable filament between said end plates axially of said electron tube, a cylindrical control grid insulatingly supported from each of said end plates, and insulation means coupling the adjacent ends of said control grids and I maintaining said control grids in concentric respect to said anodes.

lationwith respect to said filament and with re- 5. A demountable electron tube comprising a pair of cylindrical anodes, said cylindrical anodes each having a shoulder on opposite ends thereof, an insulating sleeve disposed between the shoulders on the ends of adjacent cylindrical anodes, an insulating sleeve engaging the'opposite ends of each of said cylindrical anodes, end plates extending laterally withrespect to said last mentioned sleeves, means interconnecting said end plates for maintaining said end plates in position with respect to said anodes and said sleeves for providing a substantially closed chamber, means for supporting a replaceable filament between said end plates axially of said electron tube, a cylindrical control grid insulatingly supported frome'ach of said end plates, and a ring member of insulating material extending concentrically within the inside diameters of each of said control grids for supporting said control grids in demountable'relation concentrically with respect to said filament and said anodes.

6. A demountable electron tube comprising a pair of cylindrical anodes, said cylindrical anodes each having a shoulder on opposite ends thereof, an insulating sleeve disposed between the shoulders onthe ends of adjacent cylindrical an odes, an insulating sleeve engaging the opposite ends of each of said cylindrical anodes, end plates extending laterally with respect to said last men tioned sleeves, means interconnecting said end plates for ma ntaining said endplates in position with respect to said anodes and said sleeves for providing a substantially closed chamber, means forsupporting a replaceable filament between said end plates axially of said electron tube, a cylindricalcontrol grid insulatingly supported from each of said end plates, a ring member carried by the adjacent ends of each of said control grids i in spaced relation one to the other, and an in sulating bushing having 'a central shoulder and oppositely extending cylindrical portions fitting within the said ring members for insulatingly mounting said control grids in concentrical relation with respect to said filament and said anodes.

'7. A demountable electron tube comprising a pair of cylindrical anodes, said cylindrical anodes each having a shoulder on opposite ends thereof, an insulating sleeve disposed between the shoulders on the ends of adjacent cylindrical anodes,

an insulating sleeve engaging the opposite ends of each of said cylindrical anodes, end plates extending laterally with respect to said last mentioned sleeves, means interconnecting said end plates for maintaining said end plates in position with respect to said anodes and said sleeves for providing a substantially closed chamber, means for supporting a replaceable filament between said end plates axially of said electron tube, a cylindrical frame insulatingly supported on each of said end plates, an insulating member interconnecting said cylindrical frames in a position intermediate the ends of said anodes, a control grid Wound upon each of said cylindrical frames, and e a terminal insulatingly mounted on each of said end plates and connected with the control grid supported thereon.

8. A demountable electron tube comprising a pair of cylindrical anodes, said cylindrical anodes each having a shoulder on opposite ends thereof, an insulating sleeve disposed between the shoulders on the ends of adjacent cylindrical anodes, an insulating sleeve engaging the opposite ends of each of said cylindrical anodes, end plates extending laterally with respect to said last mentioned sleeves, means interconnecting said end plates for maintaining said end plates in position with respect to said anodes and said sleeves for providing a substantially closed chamber, means for supporting a replaceable filament between said end plates axially of said electron tube, a frame insulatingly mounted on each of said end plates, means insulatingly connecting said frames in a position intermediate said anodes, a control grid wound upon each of said frames, a terminal insulatingly mounted on each of said end plates and connected with the control grid supported on the frame carried by the said end plate.

9. A high power electron tube comprising a pair of tubular anodes, an insulating sleeve disposed between said anodes, an insulating sleeve carried by the opposite ends of said anodes, end plates extending laterally across the ends of said last mentioned sleeves, means for securing said end plates, said insulating sleeves and said anodes in assembled relation for provid ng a closed chamber therebetween, a replaceable filament supported between said end plates, insulation means carried by the interior face of each of said end plates, a tubular control grid supported by the insulation means on each of said end plates, said control grids projecting toward each other, and insulation means interconnecting said control grids and disposed about said filament for centering said control grids concentrically within said chamber.

10. A high power electron tube comprising a pair of tubular anodes, an insulating sleeve disposed between said anodes, an insulating sleeve carried by the opposite ends of said anodes, end plates extending laterally across the ends of said last mentioned sleeves, means for securing said end plates, said insulating sleeves and said anodes in assembled relation for providing a closed chamber therebetween, a replaceable filament supported between said end plates, insulation means carried by the interior face of each of said end plates, a tubular control grid supported by the insulation means on each of said end plates, said control grids projecting toward each other, and a tubular insulator disposed between the adjacent ends of said tubular control grids and in alignment with the insulating sleeve between said anodes.

11. A high power tube comprising a pair of fluid cooled tubular anodes, each of said anodes having a projecting sleeve thereon, an insulating bushing enveloping the projecting sleeves on the adjacent ends of said anodes, an insulating bushing on the opposite ends of said anodes, end plates extending laterally of said last mentioned insulating bushing, means for compressing said end plates, said insulating bushings, and said anodes in sealed relation for providing a substantially air tight closure, a removable filament extending axially between said end plates, separable control grids carried by each of said end plates, and means for maintaining said control grids in concentric spaced relation with respect to said filament and said anodes.

12. A ln'gh power tube comprising a pair of fluid cooled tubular anodes, each of said anodes having a projecting sleeve thereon, an insulating bushing enveloping the projecting sleeves on the adjacent ends of said anodes, an insulating bushing on the opposite ends of said anodes, end plates extending laterally of said last mentioned insulat- [05 ing bushing, means for compressing said end plates, said insulating bushings and said anodes in sealed relation for providing a substantially air tight closure, a removable filament extending axially between said end plates, independent control grids insulatingly supporting each of said end plates and projecting toward each other, and a tubular insulator forming an annulus about said filament and engaging adjacent ends of said control grids for maintaining said control grids in spaced relation concentric with said filament and said anodes.

LOUIS A. GEBHARD.