US2396772A - Electronic discharge device - Google Patents

Description

March 19, 1946. DAlLEY 2,396,772

. ELECTRONIC DISCHARGE DEVICE Filed Aug. 13, 1945 Z1 Z0 3g I i 27:. 15 f m w 56 25 g 55 55 INVENTOR 512 ATTORNEY W/uwm Patented Mar. 19, 1946 ELECTRONIC DISCHARGE DEVICE Hampton J. Dailey, Bloomfield, N. J assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application August 13, 1943, Serial No. 498,463

4 Claims.

My invention relates to electronic discharge devices and more particularly to water-cooled high power tubes for high frequency service.

The known discharge tubes with water-cooled electrodes, in particular internally cooled anodes, have some shortcomings peculiar to the electrode ccnstructions and cooling means heretofore availa le.

One of these shortcomings is the relatively low eificiency of these tubes at frequencies in the order of 40 megacycles and above. This inefficiency at high frequencies is due to the long leads required in the known water-cooled tube constructions and to the additional tube inductance and capacitance caused thereby. The same causes are apt to render the tube operation rather unstable at high frequencies.

Another disadvantage of the known high power tubes with cooled anodes is the necessity of providing large-diameter metal-to-glass seals, thereby adding to the difficulties and cost of manufacturing the tubes.

It is an. object of my invention to provide high power tubes With internally cooled anodes which avoid the above-mentioned deficiencies of the known discharge devices of this kind.

More specifically, the invention aims at providing a highly effective cooling of an anode by passing a cooling agent from the outside of the tube envelope through the anode structure while reducing the length of the electrode leads to a minimum in order to increase the efficiency and stability of the tube operation.

Another object of the invention is to provide a water-cooled anode within a sealed envelope while requiring only small diameters for the metal-toglass seals between the electrodes, in particular the water-cooled hollow anode, and the envelope.

Still another object lies in the provision of incoming and outgoing conduit means for circulating a cooling agent from the outside of a vitreous tube envelope through a hollow anode structure and. reducing the metal-to-glass connection of the anode structure and both appertaining conduits to a single seal.

It is also an object of the invention to provide a simplified and improved construction of a hollow anode with appertaining fluid conduits for cooling agent, which ensures a thorough and even cooling effect of the entire efiective discharge surface of the anodewhile being simple to manufacture in line with the other advantages and objects previously mentioned.

To accomplish these objects, and in accordance with the present invention, I provide within the sealed envelope of a discharge device a centrally arranged cathode and a substantially cylindrical anode surrounding the cathode, and construct this anode in the form of a hollow jacket with a cylindrical partition or bafile placed between the inner and outer jacket walls so as to form two concentric jacket spaces. These spaces communicate with each other near both axial ends of the jacket for the passage of cooling agent from one to the other space. Also according to my invention, two concentric fluid conduits or tubes are provided for circulating the cooling agent through the jacket. These conduits pass together through the Wall of the envelope and are connected with the outer and innerjacket space respectively.

In accordance with another feature, the justmentioned concentric conduits extend substantially in a radial direction relative to the anode jacket and leave the tube envelope through its peripheral wall, while the cathode leads pass through one of the axial ends of the envelope. When applying the invention to grid-controlled tubes, the grid lead extends also axially but is arranged at the other end of the envelope so that the conduits, cathode lead and grid lead form a substantially T-shaped arran ement.

These and other objects and features of the invention will be apparent from the following description of the embodiments shown in the drawing in which Figure 1 represents a longitudinal sectional view of a complete disclosure tube according to the invention, Figs. 2 and 3 show two cross sections of the electrode assembly of the same tube taken along the two respective planes denoted in Fig. 1 by the dot-and-dash lines marked II and III, while Figs. 4 and 5 show in part-section two diiferent modifications-of the water-cooled anode structure to be used in tubes otherwise similar to that of Fig. 1.

Referring to Figs. 1, 2 and 3, the vacuum-tight enclosure of the illustrated discharge tube is denoted by l. The enclosure consists preferably of glass'or other vitreous material and has an elonminals carry an insulating plate H which forms a base for the cathode structure.

Two approximately semicircular metal plates l2 and I3 are mounted on the insulating base ll, each carrying two conductive holders [4, I5

and l6, II respectively. Two cathode filaments l8 have their ends attached to the holders while their central portions are passed over a metallic support I 9 which is suspended from a rodshaped central holder 20 also of metal. The holder 20 traverses the insulating base II and is connected with end 9 of terminal 6 so as to form a center tap as regards the filaments I8.-

The just-mentioned cathode structure extends substantially in the longitudinal axis of the envelope.

A grid assembly 2|, here exemplified by a cagelike structure composed of longitudinal rods and peripheral wires, is arranged coaxially to the cathode structure. It is connected with a grid lead 22 which passes through a re-entrant' neck portion 23 of the envelope 1 to theoutside at the axial end of the envelope opposite to the abovementioned terminals 5, 6 and 1. A metal sleeve 24 serves to provide a vacuum-tight metal-toglass seal between the grid assembly and the envelope I.

- The anode structure is composed of three concentric cylinders 25, 26 and 21 which are nested in one another and arranged so as to surround the cathode structure and grid assembly along the entire periphery of the arrangement. The outer cylinder 25 is of straight cylindrical shape while the inner cylinder .Z'llhas its axial ends bent towards the outer cylinder 25 and .sealed thereto in a vacuum-tightmanner. The intermediate cylinder "26 is spaced from the outer and inner cylinder and at both ends shorter than the latter cylinders. Suitable spacing knobs or protuberances '28 integral with cylinder 2 6, are provided for maintaining the proper spacing. For the purpose of convenient manufacture the cylinder 21 is composed of three sectors whose longitudinal edges abut and the sectors joined together by means of small cleats 29 which are placed over the .butt jointsand welded to the two adjoining sectors.

Due to the just-mentioned arrangement, the cathode structure forms a cylindrical hollow jacket for the circulation of a cooling agent such as water,- and the cylinder -21.forms a battle .for guiding the flow of cooling agent along the anode surf-ace walls and from one to the other jacket space. Inorder to obtain most favorable cooling conditions, the central portion of the composite inner cylinder 21 forms .a bulge at 38 so as to offer a larger volume .region at the .inlet placeof the "cooling agent. .Due to the fact that the cylindrical "path of fluid flow. between cylinders'26 and?! is rather narrow in the two axial end sections of the structure, these sections form a high velocity-region for the fluid flow. .As a result, the turbulence in these latter regions is increased :so that steam bubbles, should they occur, are more safely swept away than would be the case with a non-turbulent flow of cooling agent.

Two concentricconduits of tubular shape, denoted by 3i and 32, are provided for supplying the anode jacket with cooling agent. The inner tube 3! is connected with the ba'file cylinder 26 so as to open into the large volume'region of the jacket space within the cylinder 26. The outer tube 32 is connected with the outer anode cylinder 25 and opens into the outer jacket space. The concentric tubes 3| and 32 extend substantially in a radial direction relative to the anode structure and envelope and'traverse the peripheral wall of the envelope. A metal "sleeve 33, arranged concentrically to the tubes 3| and 32; is

sealed to the outer anode cylinder 25 and to a re-entrant branch portion 36 of the envelope I in order to establish a vacuum-tight metal-toglass seal and serves also for supporting the anode structure. The tubes 3!, 32 and the sleeve 33 are located substantially near the center portion of the anode structure. Both tubes 3| and 32 are of metal, and one or both of them serve also as an electric anode .lead. For reasons of convenient manufacture and assemblage, an annular metal body 35 is interposed between the cylinder 25 and the sleeve 33 and tightly welded or soldered to these two elements. The body 35 has an inner thread engaged by the threaded .end of tube 32. The other end of the tube 32 is closed by an attachment '36 which forms the anode terminal for connection with the plate circuit of the device and may also serve as an additional support for the device. A branch pipe 31 attached to tube 32 forms the necessary outlet for the cooling agent.

'When in operation, the cooling agent is supplied through .the inner tube 3| as indicated by the arrow .38 and reaches at first the large volume region of the inner jacketspace within the battle cylinder 25. Thence it flows in upward and downward directions through the high velocity regions to the edges of the cylinder '26 and into the outer jacket space as is indicated by a group of arrows (not marked by reference numerals). From this-outer space the cooling agent is withdrawn through the outer tube 32 and its outlet branch 31 as is indicated by the arrow 39. Thence, .if'desired, the cooling agent is passed through anexterior circulation system (not shown) whereit is cooledto a .low temperature before being forced back into the supply conduit 38.

Fig. 4 illustrates a modified form of an anode construction applicable in accordance with the invention instead of the anode structure illustrated in Fig. 1. According to Fig. 4,1116 inner cylinder 41 of the structure is traight cylindrical at its upperend while the outer cylinder 55 is constricted, as .by having its upper end tapering 'to-.

wards the inner cylinder. This constricted-end of the outer cylinder is tightly sealed to a straight cylindrical and of the inner :cylinderin order to provide ascylindrical jacket space which. similar to the embodiment of .F'ig. 1, is subdivided into an inner and outer annular space by an intermediate bafile cylinder :33. The baffle cylinder may be made in this modification as an entity without subdivision into segments :as necessary in the previously described constructions.

According to the modification shown in Fig. 5, both the inner cylinder 51 and theouter cylinder 55 have their axial edges bent toWards-eachother whilethe ba'file cylinder 56 is traight cylindrical at both ends, and extends between the edges of the outer and inner cylinder. As with the construction of Fig. 4. the several cylinders may be telescoped to place in the modification ef Fig. 5 so the ballie cylinder is conveniently a one-piece construction. The edges of the three cylinders are welded or otherwise tightly sealed together to provide the jacket space for the cooling agent The baiile cylinder 56 has a number of openings 58 near its axial ends in order to provide a passage-for the cooling agent from the inner to the surrounding outer space of the anode jacket.

In both embodiments of Figs.4 and 5, the tubular conduits for the circz-ilationor coolingagent through the ia'cketare arranged and constructed similar to the first described construction as explained in connection with Fig. 1. It will be noted, however, that the cylinder arrangements according to both Figs. 4 and 5 are so haped and proportioned that the baflie cylinder 46 or 56 may be designed as a single-piece structure because it can be slipped over one end of the inner cylinder 41 or 57 before assembling both with the outer cylinder.

It will be seen from the above-described examples that the invention provides an effective cooling device for the anode of a high powe tube while permitting the electrode leads to have minimum lengths. This advantage is mainly due to the fact that the anode structure and its appertaining lead do not occupy any space in front of the openings of the cooling jacket and that the cathode and grid leads extend out of the dis "charge tube along the shortest Way possible. The

anode lead, formed by one or both of the tubular conduits 3i and 32, is likewise of minimum length and extends at a right angle to the leads of cathode and grid, thu forming together with these othe leads a generally T-shaped arrangement. As a result, a discharge device according to the invention combines an effective cooling device with extremely short leads and in this respect is superior to the known devices of comparable design and operation.

It will also be seen from the examples that only one metal-to-glass seal is required between the anode structure and the envelope and that this seal can be kept at extremely small dimensions as compared with the diameter or size of the anode. This is due to the above-described use of concentric supply conduits for the cooling agent of a single sealing sleeve 33 surrounding both conduits. The absence of large metal-to-glass seals near the axial ends of the anode has the further advantage that it permits the filament and grid assemblies to be arranged very close to the anode.

While I have hown only three different embodiment of my invention, it will be obvious therefrom to those skilled in the art that other alterations and modifications can be made without departing from the essenceof the invention as set forth in the claims following hereafter.

I claim as my invention:

1. An electron discharge tube having an envelope, a cathode, and an anode structure surrounding said cathode in said envelope, said anode structure having two ubstantially cylindric and coaxial walls radially spaced from each other and connected with each other at their axial ends to form a cooling jacket, a cylindric bafiie within said jacket c0aXia1 therewith and havin a peripheral bulge midway of its length with the crest of the bulge spaced from the outer of said Walls a distance substantially equal to the pacing of said baflie from the inner wall, and the cylindric parts of said baffie away from said bulge having closer spacing to the inner wall than to the outer wall thereby providing an acceleration channel, and means for introducing fluid to and removing the same from said jacket at opposite sides of the bulge of said baflle, whereby copious fluid supply is present at the mid-portion of the jacket in the bulge and acceleration of flow is produced therefrom through the close-spaced acceleration channel.

2. An electron discharge tube having an envelope, a cathode, and an anode structure surrounding said cathode in said envelope, said anode structure having two substantially cylindric and coaxial walls radially spaced from each other and connected with each other at their axial ends to form a cooling jacket, a cylindric baffle within said jacket coaxial therewith and having a bulge midway of its length forming a reservoir for supply of cooling fluid to the jacket from the reservoir in both longitudinal directions of the jacket, and the cylindric parts of said bafiie away from said bulge having closer spacing to the inner Wall than to the outer wall thereby providing an acceleration channel, and means for introducing fluid to and removing the same from said jacket at opposite sides of the bulge of aid baliie, whereby copious fluid supply is present at the mid-portion of the jacket in the bulge and acceleration of flow is produced therefrom through the closeespaced acceleration channel.

3. An electron discharge tube having an envelepe, a cathode, and an anode structure surrounding said cathode in said envelope, said anode structure having two substantially cylindric and coaxial walls radially spaced from each other and connected with each other at their axial ends to form a cooling jacket, a cylindric baille within said jacket forming jacket spaces inside and outside of the bafiie, said baflie having a bulge midway of its length protruding in the outside jack t space, said bulge and outer cylindric wall providing fluid passageway between the longitudinal cylindric end parts of the jacket past the bulge in said outside jacket space, and the cylindric end parts of said baffle away from said bulge having closer spacing to the inner wall than to the outer Wall thereby providing an acceleration channel, and means for introducing fluid to and removing the same from said jacket at opposite sides of the bulge of said bafiie, whereby copious fluid supply is present at the mid-portion of the jacket in the bulge and acceleration of flow is produced therefrom through the close-spaced acceleration channel.

4. An electron discharge tube havin an envelope, a cathode, and an anode structure having two substantially cylindric and coaxial walls radially spaced from each other and connected with each other at their axial ends to form a cooling jacket, a cylindric baffle within said jacket coaxial therewith and having a peripheral bulge midway of its length with the crest of the bulge spaced from the outer of said walls a distance substantially equal to the spacing of said bafile from the inner wall, and the cylindric parts of said baflie away from said bulge having closer spacing to the inner wall than to the outer wall thereby providing an acceleration channel, an inlet conduit for introducing fluid to the interior of said bulge whereby copiou fluid supply is present at the mid-portion of the jacket in the bulge and acceleration of flow is produced therefrom through the close-spaced acceleration channel, and an outlet conduit of greater cross-sectional area than the inlet conduit opening into the space between the outer of said cylindric walls and the baflle for removing the fluid from the jacket without materially retarding flow of the fluid in the acceleration channel.

HAMPTON J. DAILEY.

Images