US2480999A

US2480999A - Electron discharge device of the magnetron type

Info

Publication number: US2480999A
Application number: US685579A
Authority: US
Inventors: William C Brown; Kather Erich Nevin
Original assignee: Raytheon Manufacturing Co
Current assignee: Raytheon Co
Priority date: 1946-07-23
Filing date: 1946-07-23
Publication date: 1949-09-06
Anticipated expiration: 1966-09-06

Description

W W49. W. c. BROWN ETAL, ZAQQQ ELECTRON DISCHARGE DEVICE OF THE MAGNETRON TYPE Filed July 23, 1946 2 Sheets-Sheet l @pt R949. C V N ET EAWEW ELECTRON" DISCHARGE DEVICE OF THE MAGNETRON TYPE Filed July 23, 1946 2 Sheets-Sheet 2 F/GZ,

Patented Sept. 6, 1949 ELECTRON DISCHARGE DEVICE OF THE MAGNETRON TYPE William G. Brown, Lincoln, and Erich Nevin Kather, South Lincoln, Mass., assignors to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application Jilly 23, 1946, Serial No. 685,579

3 Claims. 1

This invention relates to electron-discharge devices, and more particularly to electron-discharge devices of the type commonly known as multipleanode m'agnetrons.

Devices of the general character to which reference has been made have heretofore been of practical value only when used at relatively high frequencies, for example, at about 3000 megacycles, or higher. At lower frequencies, the size of the device became prohibitive, the construction thereof became unduly complex, and, if the device was intended to handle appreciable power, an elaborate cooling system became necessary.

It is, therefore, the main object of the present invention to eliminate the foregoing disadvantages, and provide a multiple-anode magnetron, the construction of which is practical for use at lower frequencies, for example, in the region of 100 megacycles.

It is another object of the present invention to reduce the complexities of a relatively low-frequency magnetron by so constructing the same that the tuning circuit and magnetic field-generating means thereof are located outside the envelope of the device.

It is still another object of the present invention to provide a multiple-anode magnetron, the construction of which is simplified by eliminatil'lg the need for pole pieces.

It is a further object of the present invention to provide a multiple-anode magnetron with a simplified cooling system and yet be able to handle power of appreciable magnitude.

These and other objects of the present invention, which will become more apparent as the detailed description thereof progresses, are attained, briefly, in the following manner:

The device of the present invention comprises an envelope, made, preferably, of glass, in which there is centrally mounted a cathode. Concentrically disposed about the cathode, in spaced relationship thereto, is a plurality of anode members, each of said members including an electronreceiving element, and a fluid-receiving element in physical contact with said electron-receiving element over an appreciable area thereof. At one end thereof, alternate electron-receiving elements are electrically tied together, intervening electron-receiving elements, likewise, being electrically tied together, but at the ends opposite said first-named ends. The fluid-receiving elements partially extend exteriorly of the envelope, and are electrically interconnected by a fluid-receiving, electrically-conductive header havin inlet and outlet ports for a cooling fluid, such as water.

The header is divided into incomin and outgoing compartments, the former communicating with the fluid-receiving elements of the anode members to supply cooling fluid to such members, and the latter communicating with open-ended pipes disposed within said fluid-receiving elements to enable the removal of the cooling fluid after the same has circulated through the anode members. Thus, the anode members, in addition to being cooled, are so electrically shorted that, when of proper physical dimensions, each pair of adjacent members, together with that portion of the header lying therebetween, constitute a shorted, quarter-wave transmission line adapted to resonate at the frequency desired of the output of the device. The device is completed by providing, exteriorly thereof, and surrounding the envelope, a coil which, when energized, establishes a magnetic field in the space between the cathode and anode members, in a direction perpendicular to the electron path between said cathode and anode members.

In the accompanying specification there shall be described, and in the annexed drawings shown, an illustrative embodiment of the electron-discharge devices of the present invention. It is, however, to be clearly understood that the present invention is not to be limited to the details herein shown and described for purposes of illustration only, inasmuch as changes therein may be made without the exercise of invention, and within the true spirit and scope of the claims hereto appended.

In said drawings,

Fig. 1 is a longitudinal sectional view taken substantially through the center of an electrondischarge device assembled in accordance with the present invention; and

Fig. 2 is a transverse sectional view taken on line 2-2 of Fig. 1.

Referring now more in detail to the aforesaid illustrative embodiment of the present invention, with particular reference to the drawings illustrating the same, the numeral l0 designates a generally cylindrical envelope having a relatively deep, dome-like upper wall II and a relatively shallow, dome-like lower wall f2, said envelope being made, preferably, of glass.

The end wall H is provided with an inwardlydirected, centrally-apert'ured protuberance [3 to which is sealed a ferrule I4 made, preferably, of the material known as Kovar, said ferrule being adapted to support a cathode assembly l5 axially within the envelope it.

While not limited thereto, the cathode assembly I may be constructed substantially in accordance with the disclosure in the copending application of Benjamin B. Butler entitled Electrodes. serial No. 676,550, filed June 13, 1946, and now U. S. Patent No. 2,468,736, issued May 3, 1949. As here shown, said cathode assembly comprises a rod It made, preferably, of molybdenum, said rod being supported from a Kovar ferrule l1 sealed to a glass ring l8, in turn, sealed to a Kovar ring l9 secured to a sleeve 20, said sleeve also bein made of molybdenum and being secured to the ferrule M. The inner end of the rod I6 carries a molybdenum ring 2|, and between said ring 2| and the inner end of the sleeve there is supported a coiled electron-emissive filament 22 made, preferably, of relatively heavy tungsten. The cathode assembly is completed by a pair of shields 2'3 and 24 carried, respectively, by the sleeve 20 and the ring 2!,

Spaced from the cathode assembly l5, and disposed concentrically thereabout, is a plurality of anode members 25. Each anode member 25 comprises an electron-receiving block 26 made, preferably, of highly conductive material, such as copper, said. block being provided, near its outer wall, with a longitudinal bore receptive of the upper end of a tubular, fluid-receivin element 21, likewise, made, preferably, of copper. All of the fluid-receiving elements 21 extend through the bottom wall l2 of the envelope Ill, .being supported by Kovar ferrules 28 sealed to outwardlydirected protuberances 29 formed in said bottom wall l2.- The upper ends of the fluid-receiving elements 21 are closed, as at 30, and the lower ends thereof are open, and telescopically engaged in tubes 3| fixed in the upper wall of a fluidreceiving header 32 made, preferably, of copper, whereby all of the anode members 25 become electrically interconnected exteriorly of the envelope H]. The fluid-receiving elements 21 and associated tubes 3! are so adjusted with respect to each other that each pair of adjacent anode members 25, together with that portion of the header 32 interconnecting the same, constitute a shorted transmission-line section whose electrical length is equal to that of a quarter-wave at the frequency desired of the output of the device.

In order to suppress spurious oscillations, the upper ends of alternate electron-receiving blocks 26 are electrically tied together by a conducting strap 33, the lower ends of intervening electron receiving blocks 26, likewise, being electrically tied together by a conducting strap 3d.

The header 32 is divided, by a baille 35, into an incoming fluid compartment 36, provided with a cooling fluid inlet pipe 31 and communicating with the open lower ends of the tubes 3|, and an outgoing fluid compartment 38, provided with a cooling fluid outlet pipe 39 and communicating with the open lower ends of pipes 40 supported in the baffle 35 and extending upwardly into the fluid-receiving elements 21, whereby a circulation of cooling fluid may be maintained to and from the anode members 25.

The envelope It may be surrounded by a coil 4| which, when suitably energized, establishes a magnetic field in the space between the cathode assembly l5 and the anode members 25, in a direction perpendicular to the electron path between said cathode assembly and said anode members.

The device is completed by any appropriate means for extracting oscillatory energy therefrom, for example, a loop 42 magnetically coupled members mounted within said envelope, spaced relationship to said cathode, and parto the tubes 3| of two adjacent anode members 25, said loop having one end connected to a central conductor 43 of a coaxial transmission line, and its other end connected to a pipe 44 constituting the outer conductor of said coaxial transmission line.

This completes the description of the aforesaid illustrative embodiment of the present invention. It will be noted from all of the foregoing that the present invention provides a multiple-anode magnetron capable of handling appreciable power at relatively low frequencies, for example, frequencies in the region of megacycles. It will further be noted that by reason of the construction of the present invention, the size thereof may be held within practicable limits, and the complexities heretofore associated with relatively low-frequency magnetrons are eliminated, due, particularly, to the location of the tuning elements and the magnetic field generating means exteriorly of the device. Finally, it will be noted that although the magnetrons of the present invention are intended to handle appreciable power, the cooling system thereof is relatively simple.

Other objects and advantages of the present invention will readily occur to those skilled in the art to which the same relates.

What is claimed is:

1. An electron-discharge device comprising: a hermetically sealed envelope; a cathode mounted within said envelope; a plurality of anode members mounted within said envelope, in spaced relationship to said cathode; each of said anode members including outer and inner tubular elements; and a fluid-receiving, electrically-conductive header electrically interconnecting said anode members whereby each pair of adjacent anode members, together with that portion of said header lying therebetween, constitute a shorted transmission-line section adapted to resonate at the frequency desired of the output of the device; said header including a housin divided into fluid-incoming and fluidoutgoing compartments communicating, respec tively, with the outer and inner tubular elements of each of said anode members.

2. An electron-discharge device comprising: a hermetically sealed envelope; a cathode mounted within said envelope; a plurality of anode tially extending exteriorly of said envelope; each of said anode members including coaxially-disposed conduits; and a fluid-receiving, electrically-conductive header electrically interconnecting said anode members exteriorly of said envelope whereby each pair of adjacent anode members, together with that portion of said header lying therebetween, constitute a shorted transmission line section adapted to resonate at the frequency desired of the output of the device; said header including a housing divided into fluid-incoming and fluid-outgoing compartments communicating, respectively with the coaxial conduits of each of said anode members.

3. An electron-discharge device comprising: a hermetically sealed envelope; a cathode mounted within said envelope; a plurality of anode members mounted within said envelope, in spaced relationship to said cathode, and partially extending exteriorly of said envelope; each of said anode members including outer and inner tubular elements; a fluid-receiving, electrically-conductive header electrically interconthe outer and inner tubular elements of each of 10 ,19

said anode members; and an output coupling device disposed adjacent said anode members in the vicinity of said header.

WILLIAM 0. BROWN. ERICH NEVIN KATHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,054,126 Hollmann Sept. 15, 1936 2,189,501 Helbig Feb. 6, 1940 Blewett Sept. 30, 1947 FOREIGN PATENTS Number Country Date 443,077 Great Britain Feb. 20, 1936