US2252118A - Electron tube - Google Patents

Description

Aug. 12, 1941. w. DALL ENBACH mm. 252,118

ELECTRON TUBE Original Filed June 18, 1956 ZShets-Sheet l g- 1941- w. DALLENBACH Emu. 18

ELECTRON TUBE Original Filed June 18, 1936 2 Sheets-Sheet 2 Patented Aug. 12, 1941 ELECTRON TUBE Walter Dallenbach, Berlin-Charlottenburg, and

Alfred Allerding, Friedrichshagen, near Berlin, Germany, assignors to Julius Pintsch Kommanditgesellschaft, Berlin, Germany Original application June 18, 1936, Serial No. 85,980. Divided and this application March 25, 1939, Serial No. 264,246. In Germany June 20, 1935 2 Claims.

The present invention relates to that class of electron tube for handling (i. e, generating, amplifying or receiving) ultra-high-frequency oscillations which include a resonator of chamber form. Such tubes may be said to comprise a metallic envelope housing a set of electrodes including a cathode, a grid or its equivalent and a substantially cylindrical electrode surrounding said cathode and grid or equivalent. The cylindrical electrode provides in effect the said chamber of resonator form, and the metallic envelope, which may be either formed of metal or merely metal coated, provides a conductive outer casing and is evacuated. Again, the metallic envelope forms or includes a chamber which is dissonant with respect to the resonator chamber and the current leads connected to the electrodes pass out through the envelope, thereby tending to prevent any loss of oscillation energy which might be led away out of the resonator through the medium of the current leads.

The present application is divided out of Patent No. 2,163,589 of June 27, 1939.

Electron tubes of the class in question and having the constructional features immediately hereinbefore specified possess numerous advantages. Thus, a resonator assembly can be formed from metal, such as copper or silver, which is a good conductor both of heat and electricity, and where the envelope is evacuated it will be unnecessary to provide fused gas-tight joints where the leads pass from the resonator assembly. As to the evacuated envelope, which can be made of any suitable material, it is preferred to use metal such as iron, nickel-iron, chromium-iron or chromium-nickel which gives oflf very little vapour. In view of the choice aiiorded, it is further possible to select for the envelope materials such as nickel-iron, chromium-iron or chromiumnickel alloys which are capable of forming good fused glass gas-tight joints where the current leadspass through the envelope.

In the case of a magnetron tube, the envelope will preferably be made of non-magnetic material such as chromium-nickel alloy.

In order to dissipate heat at the high temperatures at which the tube may work, it is preferred to provide intimate contact for heat conduction between the resonator assembly and the metallic envelope. l

The envelope may include a chamber within which vaporization of getter materials may take place. Electron tubes of the class in question opcrate with extraordinary constancy of frequency, which frequency is substantially dependent upon the dimensions of the chamber constituted by the resonator assembly.

It is an object of the present invention to provide means for eflecting flue variations of the working frequency of tubes of the class in question.

Accordingly, the invention may be said toconsist in providing such a tube with an adjusting device whereby the dimensions of the resonator chamber may be varied for altering the working frequency of a tube. p

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying diagrammatic drawings, forming part of the specification- Figure 1 is a sectional elevation of an electron tube embodying the present invention; and

Figure 2 is a sectional elevation of a magnetron tube embodying the present invention.

In the embodiment illustrated in Figure 1, the evacuated metallic envelope and the resonator casing each consist of two parts 34,34 and 35, 35', respectively, which parts are respectively connected to each other by yieldable sections 32 and 33. The upper part 34 of the envelope is connected rigidly with the upper part 35 of the resonator casing by the metal plate I. The lower section 34' of the envelope is also rigidly connected with the lower section 35 of the resonator casing. The internal conductor 4, rigidly connected at the upper end with the plate I by the fused glass joint I, is provided with a sliding joint 36 (see also 36 in Figure 2) for the purpose of allowing relative movement of the two parts 35, 35' of the resonator casing. For the same purpose also the electrode II, which is completely enclosed by the resonator casing 35, 35' is provided with milled recesses 3'! in which the insulators l2 can slide axially of the tube. For adjusting the resonator there serves a micrometer device which consists essentially of a screw thread 38 on the lower part 34' of the envelope and a coaxial outer band 39 which is internally threaded for engagement with the thread 38 by means of cooperating recesses 40, 40' and a castellated packing ring 4|. When the outer band 39 is rotated, the two sections of the envelope 34, 34 slide axially.

Constructionally, the tube illustrated in Figure 1 of the accompanying diagrammatic drawings, with the exception of the adjusting means provided on the vacuum vessel, is not materially difierent from that described in Figure 2 of the specification in Patent No. 2,163,589 from which the present matter is divided. In the present case the lower end of the envelope is closed by a plate [5 of nickel-iron, chromium-iron or chromium-nickel which is distanced M4 from the bottom of the resonator casing and contains through-ducts for the current leads l6, ll of the enclosed electrode II and the cathode 9. The

annular part [8 serves in this case also for producing an intimate heat conducting contact between the resonator casing and the envelope. It divides the space between the resonator assembly and the envelope into-the two chambers I9 and 20.

' For the vaporization of getter materials in the chamber 20, there is provided the heating body 42, one pole of which is connected with the resonator casing while the other pole extends first through the annular part I8, from which it is insulated, and thereafter through the dissonant chamber IS, the point where the lead 44 passes through the plate l5 being sealed by the fused glass joint 43. Owing to the conductive connection between the resonator casing and the envelope, the heating body may alternatively be connected by one pole with the envelope. If now it is desired to vaporize the getter material during the making of the tube, an appropriate potential is applied between the envelope and the lead 44 of the heating body. The lead 44-may then be used later during working of the tube for applying a suitable potential to the resonator casing and consequently the grid electrode 8'. Owing to the fact that relatively small current is required for the working of the tube, the resistance of the coil 42 plays no part and the heating body 42 is not heated at all. In this way special leads for the heating body are avoided.

If the envelope is to be evacuated, the small tube 23 serves for connection to a pump and can be finally sealed off by fusion.

Figure 2 illustrates the present invention embodied in a magnetron tube which constructionally corresponds to that described with reference to Figure 3 in the specification of U. S. A. patent application Serial Number 85,980 from which the present matter is divided. For the purpose of efifecting the fine adjustment of the resonator, the envelope and the resonator casing consist each of two sections that are displaceable in relation to each other. The two sections of the envelope are again connected together in vacuum-tight manner by means of a yieldable section 32. The yieldable section 32 is in the present case provided at the upper end of the tube in order to facilitate accommodation of the magnet or the magnetic field coil 48. The resonator casing in the present embodiment consists of the two relatively slidable parts 45 and 46 for the purpose of varying the length of the resonator. The cylindrical part 45 constitutes the cylindrical electrode of the resonator and the part 46 of the external conductor of the high frequency conducting device. The lower end of the part 46 terminates in the enlargement 41, movable longitudinally in the electrode 45. The sliding joint 36 in the vicinity of the potential anti-node of the high frequency conducting device provides for axial extension or shortening of the internal conductors in accordance with such adjustment of the envelope as is effected.

The lower section of the envelope has at its upper end a screw thread 88. The band 39 is internally threaded and extends from the lower surface of the metal plat 8. Turning of the band 39, as in the arrangement described with reference to Figure 1, effects elongation of the envelope.

For the purpose of producing auxiliary magnetic field coaxial with the tube, there is used in the example shown a tubular magnet 48. For the purpose of avoiding useless leakage fields, the space between the envelope and the resonator electrode 45 is made only very small and in consequence the chamber is not suitable for the vaporization of the getter materials. The heating body 42 is therefore provided in a special vaporizing chamber 20 adjacent the lower end of the resonator assembly. The heating body 42 is again connected by one pole with the resonator assembly, whilst the other pole extends out through the wall of the vaporizing chamber and is insulated therefrom by the fused glass joint 43. As in the case of the preceding examples, the other leads for the electrodes in the interior of the resonator assembly extend also in this case through the dlssonant chamber iii.

For the purpose of varying the strength of the field of the magnet 48, the lower portion of the tube is provided with a support 49 which carries a movable yoke in the form of a softiron tube 50. The support 49 and yoke 50 have threaded engagement with each other and when the yoke 50 is rotated, it moves in the direction of the axis of the tube, consequently varying the amount by which the yoke overlaps the magnet 48. Thus, there may be produced a short circuit parallel to the field-in the interior of the annular magnet, by means of which the strength of the magnetic fields can be adjusted suitably for the production of oscillations in the tube.

In the case of a magnetron tube which is to 'be evacuated, the sealing tube may be brought out through the bottom of the envelope, as again indicated at 23.

What we claim is:

1. An ultra-high-frequency electron apparatus comprising a cathode, an expansible internal conductor aligned with said cathode, a cylindrical electrode surrounding, the cathode concentrically thereto, a resonator casing concentrically surrounding said electrode and comprising a pair of aligned and yieldable sections, a plate closing one end of the resonator casing and having said internal conductor fixed to and insulated from said plate, a metallic envelope concentrically surrounding said resonator casing and closed at one end by said plate, said envelope comprising aligned sections and yieldable means connecting said sections, and an outer band screwed on one section of the metallic envelope and engaging the other to regulate the distance between the sections of the metallic envelope.

2. The apparatus of claim 1 having a flange on the resonator casing engaging one section of the metallic envelope and dividing the space therein into a pair of chambers, said flange engaging the section of the envelope remote from the plate whereby relative movement of the envelope sections causes like relative movement of the sections of the resonator casing.

, WALTER DALLENBACH.

ALFRED ALLERDING.

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