US2513920A

US2513920A - Fluid-cooled electric discharge device

Info

Publication number: US2513920A
Application number: US768697A
Authority: US
Inventors: Walt Kenneth C De
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1947-08-14
Filing date: 1947-08-14
Publication date: 1950-07-04
Anticipated expiration: 1967-07-04

Description

July 4, 1950 K. c. DE WALT Fwmcoomn ELECTRIC DISCHARGE DEvIcE Filed Aug. 14, 1947 Ihventor: Kenneth C. DeWalt, bgm'zm His Attorneg.

Patented July 4, 1950 FLUID-COOLED ELECTRIC DISCHARGE DEVICE Kenneth C. De Walt, Scotia, N. Y., assignor to General Electric Company, a corporation of New York Application August 14, 1947, Serial No. '768,697

Claims. (Cl. Z50-27.5)

My invention relates to improved fluid-cooled electric discharge devices and particularly to devices of this character adapted for high-frequency, high-power applications.

It is diicult to extend the power rating of high-frequency electric discharge devices since the requirements that the lead-in inductance and inter-electrode capacities be kept small tend to result in a small compact structure. This makes it extremely difficult to dissipate the amount of heat that must be dissipated for higher power ratings. In accordance with an important aspect of my invention, I provide an improved highfrequency electric discharge device including a novel fluid-cooled grid electrode structure. My invention is an improvement on the prior Elder and Crawford invention, described and claimed in copending application Serial No. 650,701, filed February 27, 1946, which issued as U. S. Patent No. 2,489,872 on November 29, 1949.

It is an object of my invention to provide a new and improved high-frequency electric discharge device.

It is another object of my invention to provide a new and improved fluid-cooled electric discharge device.

It is a still further object of myinvention to provide an improved duid-cooled grid electrode structure.

My invention will be better understood by reference to the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the drawing, Figure 1 is an elevational view in section of an electric discharge device embodying my invention; Figure 2 is a sectional view taken along the line 2-2 of Figure 1; Figure 3 is an elevational view partially in section of a, modication of my invention, and Figure 4 is a sectional View taken along the line 4-4 of Figure 3.

Referring now to Figure 1 of the drawing, I have shown my invention embodied in an electric discharge device of the transmitting type and including a generally cylindrical open ended anode I which together with a water jacket 2 forms a part of the envelope of the device. As illustrated, the lower portion of the anode is provided with helical ns 3 which define a plurality of cooling passages 4. These passages communicate with a header 5 at the lower end of the anode and with a pair of chambers 6 and 1 provided between the upper portion of the anode and the water jacket and communicating respectively with inlet and outlet conduits 8 and 9. The chambers 6 and 'l do not communicate with each other except through the spiral passages so that the fluid circuit includes, in series, the chamber 6, certain of the spiral passages 4, the header 5, the remaining passages 4, and the chamber l. As illustrated in the drawing, the water jacket is bonded to the lower end of the anode and is joined to the remainder of the envelope by a reversely bent generally annular sheet-metal member I0 which is bonded at one end to the Water jacket 2 and at the opposite end is sealed to a cylindrical glass wall member II. A second glass wall member I2 is joined to the member Il by a cylindrical sheet-metal member I3 which is sealed by the adjacent edges of the members II and I2. The member I3 provides a support for the grid structure of the device designated generally by the number I4 as Well as an externally accessible terminal for the grid structure. A reinforcing terminal ring I5 is bonded to the exterior of the sheet-metal cylinder I3.

The remainder of the envelope is constructed to provide a pair of concentrically arranged terminals for the iilamentary cathode structure. As illustrated, a sheet-metal member I6 of generally annular shape and having a substantially U- shaped cross section in a radial plane, provides one terminal for the cathode as well as an end portion of the tube envelope. A second cathode terminal is provided by the solid cylindrical conductor l1 arranged within the annular member I6 and joined to the inner edge thereof by a glass cylinder I8 which is sealed at one edge to the member l and at its opposite edge to a metal member I9 bonded to the inner end of the terminal Il. The glass ring I8 and member I9 together with the inner ange of the terminal member I 6 provide a reentrant portion at the end of the tube envelope and the members I6 and I'I provide concentrically arranged termipals and supports for the cathode structure. As illustrated, in the drawing, a centrally arranged rod 29 is supported in a recess formed in the inner end of the central terminal I'I and is rigidly secured thereto. A support and terminal for one-half of the cathode elements are provided by a spider El supported in iixed relation. to the rod 2U at a point adjacent the lower end oi the anode. In the particular embodiment illustrated, the cathode elements 22 are in the form of flat ribbons of thin sheet nickel or si-. ilar materia-l which are coated on the exterior surfaces with a suitable mixture of alkaline earth oxides for improving the electron emitting properties of the elements. As shown in Figure 2, the spider 2| has three equally spaced arms which are turned upwardly at their extremities and are bonded to the cathode elements. A cathode supporting spider 23 is supported in spaced rela tion to the spider 2l and adjacent the free end of the centrally located rod 29. This spider is provided with six arms which are bonded to the upper ends of the cathode elements. rIhe lower ends of the remaining three cathode elements are bonded to the arms of a third spider 23 which is supported in fixed and electrically conducting relation with respect to the envelope and terminal member I6 by sleeves 25 and 2t. The sleeve 26 is provided with an outwardly directed fiange 2l which is bonded to the inner surface of the envelope wall I and with a conical portion 28 which is bonded to the smaller sleeve 25.

' The upper filament supporting spider is urged upwardly by a lament tensioning construction to maintain the filament under tension during operation. The spider is centered by a bearing member 29 of insulating material which slides on the rod and which is engaged by a metal sleeve 30 surrounding the central supporting rod 29. The vsleeve 39 is in turn biased upwardly by a compression spring 3l received within a recess 32 lprovided in the inner end of the terminal Il and a motion transmitting

structure including washers

33 and 33 which are interconnected by a plurality (three in the illustrated embodiment) ofk rods 34. It will be apparent from the foregoing description that the cathode construction just described provides three parallel electrical paths between the terminals I6 and I'I with each path including two of the vcathode elements 22 in series. In order to provide for eif'ective cooling of the seals lbetween the member I6 and the glass rings I2 and I8, a cooling block and terminal 35 in the form of a cylinder is brazed to the envelope Iwall I6. The cylindrical member `35 is provided with a cooling passage 36 in proximity to the wall of the envelope.

VIn accordance with an important aspect of my invention, I provide an improved duid-cooled grid structure supported from the metal ring I3 of the envelope wall. As illustrated, in the drawing, the grid proper is provided with a helically wound conductor 31 which is supported from the cylindrical terminal I3 by means of a generally cylindrical array of folded conduit 38 and a pair of supporting sleeves 39 and 40. The sleeve 40 is bonded to the envelope terminal member i3 as provided with an inwardly directed flange 4I which supports the sleeve 39. The supporting and cooling structure provided by the conduit 38 is in the form of a plurality of series connected loops of conduit which `provide a circular array of grid wire supports. The lower loop portions 42 are bentoutwardly at the lower ends thereof and are bonded to the inner surface of the tapered sleeve 39. The upper loops 43 are bonded to and provide a support for a grid cap fifi. The free ends 45'and 46 of the conduit 38 are sealed through the terminal member I3 and provide eX- ternally accessible inlet and outlet fluid connections for the grid structure.

It is apparent from the foregoing detailed description that the present invention provides for an adequately cooled system of electrodes in a structure which also provides for relatively short conductive connections with each of the electrodes so that the lead-in inductance is minimized. The operation of a device embodying my invention,

as described above, indicates that a power output of 10 kilowatts at a frequency of 220 megacycles is readily obtained with a very compact tube structure.

In Figures 3 and 4, I have illustrated a modiication of my invention which is, as far as its general organization is concerned, similar to that shown in Figures 1 and 2 and the same reference .numerals have been applied to the corresponding parts. In the modied form of my invention, the major difference is in the water-cooled grid electrode structure. As shown in Figures 3 and 4, the grid conductor 31 is supported by a watercooled spider or hub 4'! which is bonded at its lower end to a grid supporting sleeve 48. The sleeve 48 is in turn bonded to a flange member 49 which is supported from the grid terminal sleeve I3 by a sleeve 40. As shown in Figure 4, the spider is provided with six radially extending arms 47 which provide a circular array of supports for the grid wire. A wire 49 of nickel is inserted in the face of each of the radially eX- tending arms to provide a good bonding surface for the grid wire which is tantalum, molybdenum or tungsten. The grid. structure is designed to be iiuid cooled and is provided kwith an annular passage 59 near the upper end thereof ywhich communicates with a pair of conduits 5I and '52 through longitudinal passages 53 and 54' formed in the body of the spider. As illustrated in Figure 4, the spider is provided with a central passage 55 of sufficient size to allow clearance around the filament tensioning structure. The spider is also recessed in the central portion of Athe lower end as shownL at 59 in Figure 3 to 'accommodate the filament supporting spider 2| and the conduits 5I and` 52.

Whilel' have shown and described a particular embodiment of my invention, it will be apparent to those skilled in the art that many changes and modications may be. made without departing from my invention in its broader aspect, and I aim, therefore, in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

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

1. A fluid-cooled grid electrode structure cornprising a cylindrical conductive sleeve forming a portion of an envelope wall and providing an eX- ternally accessible grid terminal, a conductive structure supported from .said sleeveV including a second cylindrical sleeve of smaller diameter than said first-mentioned sleeve and positioned in coaxial relation with respect thereto, a conductive structure supported from said second sleeve and providing a cylindrical array of supports for a grid conductor, a grid conductor wound upon said supports, said conductive structure liavingpasr sages provided therethrough for cooling fluid and conduits extending through said first-mentioned sleeve and communicating with said passages to provide externally accessible inlet and outlet iiuid connections.

2. A fluid-cooled grid electrode structure comprising a cylindricalconductive sleeve forming a portion of an envelope wall, a conductive structure supported from said sleeve including a second cylindrical sleeve of smaller diameter than said first-mentioned sleeve and positioned in coaxial relation with respect thereto, a conductive struc-'- ture supported from said second sleeve and providing a cylindrical array of supports, said conductive structure having passages 'provided therethrough for cooling fluid and conduits ex'- tending through first-mentioned sleeve and communicating with said passages to provide externally accessible inlet and outlet fluid connections.

3. A uid-cooled grid electrode structure cornprising a cylindrical conductive sleeve forming a portion of an envelope Wall, a conductive structure supported from said sleeve including a second cylindrical sleeve of smaller diameter than said first-mentioned sleeve and positioned in coaxial relation with respect thereto, a conductive structure providing a cylindrical array of supports extending Within said second sleeve and secured thereto, said conductive structure having passages provided therethrough for cooling uid and conduits extending through said first-mentioned sleeve and communicating with said passages to provide externally accessible inlet and outlet uid connections.

4. A fluid-cooled grid structure including a conducting sleeve, a cylindrical array of conduits joined together at opposite ends providing a series fluid path, a conducting sleeve surrounding one end of said conduits and bonded thereto, a grid cap bonded to the other end of said conduits, a second sleeve forming a part of the envelope and supporting said grid structure, and a pair of conduits sealed through said sleeve and connected with said conduits to provide externally accessible iluid connections for said grid structure.

5. A fluid-cooled grid structure including a conducting sleeve, a cylindrical array of conduits joined together at opposite ends providing a series fluid path, a conducting sleeve surrounding one end of said conduits and bonded thereto, and a second sleeve forming a part of the envelope and supporting said grid structure and a pair of conduits sealed through said sleeve and connected with said conduits to provide externally accessible iiuid connections for said grid structure.

KENNETH C. DE WALT.

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

UNTTED STATES PATENTS Number Name Date 2,020,428 Mouromtsefi" Nov. 12, 1935 2,441,349 Eitel et al May 11, 1948 FOREIGN PATENTS Number Country Date 474,933 Great Britain Nov. 10, 1937