US1680691A - Electron-discharge device - Google Patents

Description

Aug. 14, 1928.

H. J. NOLTE ELECTRON DISCHARGE DEVICE Original Filed Feb. '7. 1921 /&

lnx/e ntorz Henry J Nome,

His Attorney.

Patented Aug. 14, 1928. I

UNITED STATES 80,6 PATENT OFFICE.

HENRY J. NOLTE, OF SCHENECTADY, NEW YORK, ASSIGNOB '10 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRON-DISCHARGE DEVICE.

Original application filed February 7, 1921, Serial No. 443,005. Divided and this application filed September 18, 1923.

My presentinvention, which is a division of my rior application, Serial No. 443,005, filed ebruary, 7, 1921, relates to electron discharge devices, and more particularly to devices of the type employing at least three electrodes, comprising a cathode, an anode and a grid member for controlling-the passage of an electron stream between cathode and anode.

The object of my invention is to provide an eflicient and convenient method for removing occluded gas from the electrodes of such devices during the process of exhaust. The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims; the invention itself, however, will best be understood b reference to the following description talzen in connection with the accompanying drawing in which Fig. 1 is a view partly in section of a device with which my invention may conveniently be employed; Fig. 2 is a view of the grid and the structure whereby it is supported; and Figs. 3 and 4 are detail views of portions of the grid structure.

The device indicated in the drawingcomprises an evacuated receptacle comprising a portion 1 of glas and a portion 2 of metal. The lass portion is sealed to the metal ortion y means of a thin metal ring 3 w 'ch is preferably of copper or an alloy having substantially the same coefiicient of. expansion as the glass of which the art 1 is composed. This rin 3 is solder or 'welded to the portion 2 and forms a gas-tight seal with the glass at the-region 4 where it is surrounded by the glass wall of the portion 1. The filamentary cathode 5, which is prefer- I ably of tungsten is supported within the receptacle by means of supporting arms 6, 7 and 8, the arms 6 and 7 also serving as supply conductors of the cathode. The grid 15, which surroundsthe cathode is in the N. form of a cylindrical screen made up "of two sets of wires 16, 17, which are wound spirally in opposite directions and interwoven. By means of this construction the principal'expansion ofthe grid when heated will occur in the direction of its diameter and the tendency of the grid to buckle and make contact with the filament or anode will be largely eliminated. The ends of these two se s of grid are se ured 2 Serial No. 663,470.

rings 18., and 19 by means of binding wires wound around these rings. Supporting arms 20 are secured to these two rings and together with the rings form a rigid support for the grid. These supporting arms and the end rings preferably are made of tungsten or similar metal from which the oc-.

its edges. This strip of metal is bent into the form of a ring, these ears bent over and the arms 20 inserted through the holes 23 in the cars 22. The arm 20, which passes through the holes 23 at the ends of the strip which comes opposite each other also serves to hold the two ends of the strip together. After the arms 20 are inserted in these holes the ears may be squeezed or bent in such a way as to firmly grip the arms 20 and'thereby secure the parts together without the necessity of any weldedor soldered joints.

The grid structure described is supported in I the desired position in the receptacle by means of a sleeve 24 which surrounds the reentrant tubular portion 12 and is securely fastened thereto by means of clamping screw 25. S'upport' arms 26 are secured to this sleeve 24 and e members 20 which are of considerabl smaller-diameter than the diameter of t e arms 26 are fastened to the arms 26 in the manner indicated at 27 in Fig. 2. For convenience in the construction of the device the end of the portion 2 of the receptacle may be left open until the arts have been sealed together and then 0 osed by means of a cap 28 which is soldered to the receptacle or welded thereto to form an air-tight joint. K

In the operation of the devicedescribed for the control of large energies, the anode 2 should be artificially cooled. This may be accomplished by placing it in a bath of water or other suitable cooling liquid and providing means to insure d circulation of the cooling liquid. In view of the fact,

therefore, that the anode 2 will normally operate at a low temperature, it is possiblg to make use of metal for its construction having a com aratively low melting, point. I have found is at copper is very suitab e for this purpose. I

5 In the exhaustion of the device described,

toremove all air as well as all the gases potential is connected between cathode and anode so that the anode will be bombarded by electrons emitted'from the cathode. At'

this point in the exhaust the cooling medium 0 is applied to the anode to protect it from ,over eating and the gas removed during this stage ls therefore removed principally as a result of bombardment Occluded gas is also removed from the grid structur'e by bombarding the grid and its supporting parts by electrons given off from the cathode. What I claim as new and desire to secure by Letters Patent of the United States is 1. The method of removing occluded as during the exhaustion of an electron ischarge device comprising a filamentary cathode adapted to be heated to incandescones and an anode, which'consists in first heating the anode, by heat radiated from the cathode, to a temperature sufiiciently high to drive ofi a large portion of the occluded gas in the metal parts of the device, and then bombarding the anode b means of electrons emitted from the catho e.

2. The method of removing occluded gas during the exhaustion of an electron discharge device comprising a cathode adapted to be heated to incandescence and an anode, which consists in first heating the anode by heat radiated from the cathode, then bombarding the anode by means of electrons emitted from the cathode and maintaining the anode at an appreciably lower temperagure during the second step than during the 'rst. t

3. The method of removing occluded gas during the exhaustion of anelectron discharge device comprising a cathode adapted to be heated to incandescence and an anode which consists in first heating the anode by heat radiated from the cathode, then bombarding the anode by means of electrons emitted from the cathode and simultaneously supplying a cooling medium to the anode.

4. The method of removing occluded as during the exhaustion of an electron 'scharge device includin a cathode and an anode, which comprises eating the anode to a red heat by means of heat radiated from the cathode, and then bombarding the anode by means of electrons emitted from the cathode.

In witness whereof, I have hereunto set my hand this 17th da of September, 1923.

NRY J. NOLTE.

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