US2381632A - Electron discharge device - Google Patents
Electron discharge device Download PDFInfo
- Publication number
- US2381632A US2381632A US503598A US50359843A US2381632A US 2381632 A US2381632 A US 2381632A US 503598 A US503598 A US 503598A US 50359843 A US50359843 A US 50359843A US 2381632 A US2381632 A US 2381632A
- Authority
- US
- United States
- Prior art keywords
- grid
- anode
- cathode
- envelope
- shield
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J17/00—Gas-filled discharge tubes with solid cathode
- H01J17/50—Thermionic-cathode tubes
- H01J17/52—Thermionic-cathode tubes with one cathode and one anode
- H01J17/54—Thermionic-cathode tubes with one cathode and one anode having one or more control electrodes
- H01J17/56—Thermionic-cathode tubes with one cathode and one anode having one or more control electrodes for preventing and then permitting ignition, but thereafter having no control
Definitions
- This invention relates to electron discharge devices of electronic characterization, and more especially such devices of the general nature of arc rectiers, particularly thyratrons.
- the usual attributes of a thyratron are the provision of a cathode, grid, anode and small amount of vapor or inert gas by virtue of which a current passes through the device as an arc, starting whereof is controlled by the grid but wherein the grid exercises no further control after the arc starts either to modulate, limit or extinguish the arc.
- the arc is stopped periodically by reversal of the anode voltage.
- the cycle of starting and stopping repeats at a rate dependent on the supply frequency so the tube operates with an intermittent arc discharge and is capable of controlling large currents. Emission from the grid is detrimental in use because of its effect in prematurely starting the discharge; and fundamentally an object of the present invention is to overcome undesirable grid emission and premature starting or loss of control.
- a further basic object of the invention is to provide adequate heat-dissipation from the grid to maintain and operate the grid at as low a temperature as possible.
- Further objects of the invention are to provide for rigid support for the grid; to readily obtain and maintain proper alignment; provide for lead-in thereto from the press and stem rather than from the envelope wall; to provide for adequate thermal and electrostatic shielding and control of the electron flow and onset of ionization; and to simplify the construction and manufacturing operations.
- Figure 2 is a similar view of a portion of the showing of Fig. 1 in section, as on line II--II of Fig. 3, but on larger scale; and v Figure 3 is a cross-sectional view on line III-III of Fig. 1.
- the reference numeral I0 designates a glass or other suitable envelope of an electron discharge device which is evacuated and provided with a small quantity of ionizable inert gas, such as mercury vapor, helium, neon, argon, Xenon and the like.
- the envelope is provided with a reentrant stem II through which lead wires are sealed for making connection with exterior terminal prongs I2 on the bottom of an attached base I3.
- the opposite end of the envelope has its opposite or upper end constricted, as at I4, and capped thereab'ove with a terminal I5 which, makes connection with a depending rod I6 sealed through the glass at the upper part of the dome, toaxial therewith, by an upper stem I'I.
- the lower end of the depending rod I6 carries in the present showing, a transverse coaxial electrode constituting the anode I8 for the thyratron.
- Opposed to the anode, and suitably supported by lead-in wire 20 from the main stem at the base end of the envelope, is a cathode 2
- a control grid 22 Between the cathode and anode is a control grid 22, the construction whereof is of especial concern to the present invention. It should be called to attention at this stage, that the control characteristic of a thyratron grid is governed by the dimensions of the opening therethrough. 'I'he present showing of control grid 22 accordingly provides a single circular opening 23 for passage of electrons, said opening being coaxial to the axis of cathode and anode.
- the grid includes a generally flat and ring-shaped plate 22' with a flange 24 at its inner periphery and another flange 25 at its outer periphery, both flanges being shown projecting downwardly from the ilat portion of the said grid plate.
- the inner flange 24 denes the grid opening 23 and constitutes the portion of the grid having direct effect on the electron flow.
- the area of the grid longitudinal of the tube and represented by the interior surface of inner ange 24, is kept at a minimum, and by virtue thereof the area of grid directly exposed to theV heat emitted from the cathode and from the arc stream is small. This results in the absorption of a minimum amount of heat by the grid.
- the control grid 22 is preferably fabricated from a material of high heatl conductivity, high thermal emissivity, reasonably high melting point, and a surface which has a poisoning effect on vaporized emission coating lodging thereon, examples of such surfaces being carbonized nickel, graphite, or oxidized tungsten and chromium.
- the construction as indicated in the drawing likewise enables the grid plate 22 to be made of relatively thick material which increases the rate of heat flow transversely to the outer periphery of the control grid.
- the outer periphery of the control grid 22 consists of a radiator 2B, here shown as a metallic cylinder with the grid plate 22 therein approximately midway of the length of the cylinder and transverse thereto.
- Outer flange 25 on the grid plate enables the grid plate and radiator to be secured together with a close lit and by welding.
- the radiator is exposed to the envelope wall so that heat transmitted to the radiator from the grid plate radiates readily to the exterior and is dissipated.
- the characteristics of the control grid as specified above are important desideratums of my inproved thyratron.
- the high heat conductivity insures that the heat developed in the grid, by the heater energy and the arc energy, be conducted from the region near the grid opening as rapidly as possible.
- the high melting point of the material employed maintains the grid intact and avoids disintegrated particles from contaminating other contents of the envelope.
- the high thermal emissivity promotes the rapid dissipation of the heat developed by the cathode and discharge energy. Relative to the poisoning effect, it may be explained that it has been found that certain materials acting as bases for emissive coatings tend to minimize or reduce emission. Advantage is taken of this effect in fabrication of the present grid by using a material therefor, for instance selected from the examples above mentioned, which tends to prevent emission from the grid by emissive material lodging thereon.
- the discharge is confined largely between the cathode and anode by a cylindrical shield grid, and a feature of the invention comprises appropriately supporting and spacing the control grid and shield without electrical contact and yet have the control grid both inside and outside the shield grid and both grids coaxial.
- Presence of the shield grid is desirable for accomplishing certain purposes, amongst which are; to obtain electrostatic shielding; to reduce quantity of emissive coating from the cathode depositing on the control grid and grid insulators; to reduce the quantity of heat radiated from the cathode, anode, and arc discharge and absorbed by the control grid, thus reducing temperature of the control grid; to provide an extra control element; and to minimize the amount of glass envelope exposed to the discharge.
- the shield grid is constructed in two parts, namely a lower cylindrical section 21 around the cathode and extending almost to the grid plate 22' of control grid 22, and an upper cylindrical section 28 extending from just above said grid plate to a position well above the anode, said sections being coaxial and of equal diameters one to the other.
- Each shield grid section has a transverse annular baille therein, the upper section having its baille 29 between yand parallel to the control grid plate and anode, whereas the lower section has its baffle 30 'between and parallel to the control grid plate and cathode.
- Each baille has an opening therethrough which in the present showing has been arbitrarily made corresponding in size and axial position to that of the control grid.
- control grid plate and shield grid battles are shown each with a single opening, the size, number and relation of openings may be varied in accordance with control desired, but ordinarily it is usual to have the openings of the bailles the same size as and coaxial with the corresponding opening or openings of the control grid plate.
- the cylindrical shield grid sections are carried by a plurality of studs or supporting members 3
- the studs project upwardly from the collar at the outside of said shield grid sections 2'1, 28, and in contact with the surfaces thereof and are ultimately welded or otherwise secured thereon during assembly.
- preferably extend to the upper end of the upper shield grid section, but an upper end portion of each is left unwelded from said section, thereby enabling that end portion of the stud free to be bent outwardly.
- Said studs are of a suitably resilient metal and formed with the upper end portions normally in the bent-out or diverging position as above described.
- beads 32 Closely adjacent to the upper ends of said bent-out portions are provided beads 32, one on each stud, and shown 'I'hese beads are of high electrical and thermal resistivity of which lava is illustrative.
- a slot 33 In the upper shield grid section and in registration with each bead is a slot 33 of appropriate size, shape and location to receive the portion of the bead projecting toward the shield grid section from the stud, so that an edge portion of the bead is held in the slot, 'and keeps the bead from sliding on the stud.
- each stud insulatlve means for rigidly mounting the control grid.
- Each said means comprises an inner sleeve 34 of ceramic insulating material, such as lava, or other steatites, which extends through a hole iitting the same in the grid plate 22'.
- insulator knobs 35 On opposite end portions of the sleeve and engaging at facing ends against the grid plate, are insulator knobs 35 which preferably have their peripheral faces grooved, as at 38, for establishing a long surface path to deter current leakage longitudinally of the knobs. These knobs are received in notches 3l cut in the edges of the shield sections thereby enabling the maior portions of the shield section edges to be situated in closely spaced parallel relation to the flat portion of the grid plate.
- the construction of the present invention is one well adapted to production methods and to provide a thyratron of increased rigidity and permanence of physical and electrical characteristics and with electrode alignment readily obtained and positively maintained.
- energy received or transformed by the control grid in the form of heat is readily transmitted by the relatively thick and heat conductive material comprising the grid plate to the radiator exterior to all other parts in the envelope enabling the heat to be dissipated by radiation from the outer surface of the radiator exposed toward the exterior.
- the temperature of the control grid may be kept to very low values. The result is reduction in the amount of grid current and improved starting control for the power arc of the thyratron.
- An electron discharge device comprising an envelope and opposed cathode and anode therein, a grid interposed between said cathode and anode, a radiator on said grid in proximity to the wall of said envelope, and a shield between said radiator and both said cathode and anode.
- An electron discharge device comprising an envelope and opposed cathode and anode therein on a common axis, a grid transverse to and coaxial with said axis and interposed between said cathode and anode, a cylindrical radiator on said grid coaxial with said cathode, anode and grid and in proximity to the wall of said envelope, and a shield coaxial with and between said radiator and both said cathode and anode.
- An electron discharge device comprising an envelope and opposed cathode and anode therein on a common axis, a grid plate transverse to and coaxial with said axis and interposed between said cathode and anode, a cylindrical radiator on said grid plate with part of the radiator above and part below said grid plate and coaxial-with said' cathode, anode and grid plate and in proximity to the wall of said envelope, and a divided shield -in part above and in part below said grid plate with one saidv part between the radiator and cathode and the other said part between the radiator and anode.
- An electron discharge device comprising an envelope and opposed cathode and anode therein on a common axis, shielding means around the peripheries of said cathode and anode, and a grid interposed between said anode and cathode said grid projecting radially through said shielding means.
- An electron discharge device comprising an envelope and opposed cathode and anode therein on a common axis, shielding means around the peripheries of said cathode and anode, and a grid of greater diameter than either said anode or cathode and interposed between said anode and cathode and projecting radially through said shielding means, and means for supporting said grid from said shielding means.
- An electron discharge device comprising an 'envelope and opposed cathode and anode therein on a common axis, shielding means comprising longitudinal sections oi which one section is around the cathode and another section is around the anode, and a grid interposed between said cathode and anode said grid projecting between said sections of the shielding means.
- An electron discharge device comprising an envelope and opposed cathode and anode therein on a common axis, shielding means comprising longitudinal sections of which one section is around the cathode and another section is around the anode, a grid interposed between said cathode and anode said grid projecting between said sections, and means for supporting said grid from said sections.
- An electron discharge device comprising an envelope and opposed cathode and anode therein on a common axis, shielding means around the peripheries of said cathode and anode, a grid interposed between said anode and cathode and projecting radially through said shielding means, and a radiator on said grid outside of said shielding means.
- An electron discharge device comprising an envelope and opposed cathode and anode therein on a. common axis, a shield grid around the peripheries of said cathode and anode. a control grid interposed ⁇ between said anode and cathode and projecting radially through said shield grid, and means for supporting said control grid from said shield grid, and a. radiator on said control grid outside of said shield grid.
- An electron discharge device comprising an envelope and opposed cathode and anode therein on a common axis, a shield grid comprising longitudinal sections of which one section is around the cathode and another section is around the anode, a control grid interposed between said cathode and anode and between said shield grid sections, and a radiator on said control grid outside of said shield grid sections.
- An electron discharge device comprising an envelope and opposed cathode and anode therein on a, common axis, a shield grid comprising longitudinal sections of which one section is around the cathode and another section is around the anode, a control grid interposed between said cathode and anode and between said shield grid sections, means for supporting said control grid from said shield grid sections, and a radiator on said control grid outside of said shield grid sections.
- An electron discharge device having an envelope and electrodes of which one electrode is cylindrical and coaxial within the envelope, said cylindrical electrode being divided into two opposed sections, and another electrode transverse to said cylindrical electrode and projecting from between the said sections thereof, insulators interposed between said sections and said transverse electrode, and rods extending through said insulators and attached to both said sections.
- An electron discharge device having an envelope and electrodes of which one electrode is cylindrical and coaxial within the envelope, said cylindrical electrode being divided transversely into two opposed cylindrical sections. and another electrode transverse to said cylindrical electrode and projecting from between the said sections thereof, insulators interposed between said sections and said transverse electrode, rods extend ⁇ ing through said insulators and attached to both' said sections, and heat dissipating means at the outer periphery of said transverse electrode outside oi and spaced from said cylindrical electrode and from said rods.
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Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL68025D NL68025C (ja) | 1943-09-24 | ||
US503598A US2381632A (en) | 1943-09-24 | 1943-09-24 | Electron discharge device |
GB14779/44A GB592266A (en) | 1943-09-24 | 1944-08-02 | Improvements in or relating to electron discharge devices |
FR946964D FR946964A (fr) | 1943-09-24 | 1947-05-20 | Appareil émetteur d'électrons |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US503598A US2381632A (en) | 1943-09-24 | 1943-09-24 | Electron discharge device |
Publications (1)
Publication Number | Publication Date |
---|---|
US2381632A true US2381632A (en) | 1945-08-07 |
Family
ID=24002757
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US503598A Expired - Lifetime US2381632A (en) | 1943-09-24 | 1943-09-24 | Electron discharge device |
Country Status (4)
Country | Link |
---|---|
US (1) | US2381632A (ja) |
FR (1) | FR946964A (ja) |
GB (1) | GB592266A (ja) |
NL (1) | NL68025C (ja) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2508992A (en) * | 1948-04-19 | 1950-05-23 | Gen Electric | Electrode assembly for electric discharge devices |
US2814752A (en) * | 1954-04-19 | 1957-11-26 | Sylvania Electric Prod | Planar electron tubes |
US2822498A (en) * | 1954-04-19 | 1958-02-04 | Sylvania Electric Prod | Tube construction for automatic production |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5550430A (en) * | 1994-05-16 | 1996-08-27 | Litton Systems, Inc. | Gas discharge closing switch with unitary ceramic housing |
US5994850A (en) * | 1995-09-08 | 1999-11-30 | Eev Limited | Switching arrangements wherein a cylindrical trigger electrode is arranged around a gap between an anode and cathode for establishing a discharge therebetween |
-
0
- NL NL68025D patent/NL68025C/xx active
-
1943
- 1943-09-24 US US503598A patent/US2381632A/en not_active Expired - Lifetime
-
1944
- 1944-08-02 GB GB14779/44A patent/GB592266A/en not_active Expired
-
1947
- 1947-05-20 FR FR946964D patent/FR946964A/fr not_active Expired
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2508992A (en) * | 1948-04-19 | 1950-05-23 | Gen Electric | Electrode assembly for electric discharge devices |
US2814752A (en) * | 1954-04-19 | 1957-11-26 | Sylvania Electric Prod | Planar electron tubes |
US2822498A (en) * | 1954-04-19 | 1958-02-04 | Sylvania Electric Prod | Tube construction for automatic production |
Also Published As
Publication number | Publication date |
---|---|
GB592266A (en) | 1947-09-12 |
NL68025C (ja) | |
FR946964A (fr) | 1949-06-20 |
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