US2543702A - Magnetic field controlled gas filled discharge device - Google Patents

Magnetic field controlled gas filled discharge device Download PDF

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Publication number
US2543702A
US2543702A US668548A US66854846A US2543702A US 2543702 A US2543702 A US 2543702A US 668548 A US668548 A US 668548A US 66854846 A US66854846 A US 66854846A US 2543702 A US2543702 A US 2543702A
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United States
Prior art keywords
cathode
anode
magnetic field
tube
magnetic
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Expired - Lifetime
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US668548A
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English (en)
Inventor
Mulder Johannes Gijsbe Wilhelm
Penning Frans Michel
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/02—Details
    • H01J17/14—Magnetic means for controlling the discharge

Definitions

  • This invention relates to a device comprising an incandescent-cathode converter tube with gaseous and/or vapour filling whose discharge path between the cathode and the anode is cut by the lines of force of a magnetic iieid whose field intensity is so chosen as to obtain at least approximately the minimum value of the arc voltage of the tube as a function of this field intensity.
  • the purpose of the invention is to increase the life of the tube relatively to the known constructions to a considerable extent whilst retaining a high blocking power, and this more particularly by means of a further decrease of the arc-voltage.
  • factors were considered which had not been taken into account hitherto.
  • the construction and the arrangement of the tube and of the magnetic field are so chosen that the anode is arranged outside that part of the magnetic field which cuts the emitting surface of the cathode, preferably arranged symmetrically in the axis of the field, and the anode, from the middle of the cathode, can be seen under the largest angle of at least 120, while the strength of the magnetic field at the active surface of the anode is preferably less than gauss.
  • the discharge is concentrated to form a beam in the direction of the magnetic field which has approximately the transverse dimensions of the cathode, the light in the remaining part of the discharge vessel being weak.
  • the anode is located outside the highly luminous part of the discharge.
  • This arrangement results in the blocking power of the tube remaining high owing to the arrangement of the anode outside the magnetic field, while a low arc-voltage is obtained as a result of the discharge paths of wide sections and small length which may occur between the anode and the cathode as a result of the arrangement of the former.
  • a highly advantageous embodiment of this idea is obtained if the arrangement is so chosen that a plane anode in the form of a horse-shoe or ring is arranged with its surface normal to th axis of the magnetic field and in the surface of symmetry between the permanent magnet blocks, in which surface the cathode is arranged centrally, while the mean distance between the axis of the field and the various points of the active surface of the anode is the /2-fold of half the mutual distance between the permanent magnetic blocks.
  • Another method of decreasing the intensity of the magnetic field near the anode follows the opposite way by causing the magnetic lines of force to extend through the material of the anode itself, so that the discharge space near the anode is no longer traversed by these lines of force.
  • the anode which, if desired, may form the wall of the tube may be utilized as the external magnetic connection of the poles, remote from the cathode, of the blocks of permanent magnet material, preferably in such manner that no appreciable intensity of the magnetic field occurs along the active surface of the anode.
  • the magnetic bodies or the poles it is advisable for the magnetic bodies or the poles to be made smaller than the largest projection of the cathode in their direction.
  • the active surface of the anode should not be too small relatively to the transverse dimensions of the magnet field (pole) and of the cathode.
  • a suflicient surface of the anode is considered to be present if the width of the active surface of the anode is larger than the smallest dimension of the transverse section of the magnet pole.
  • each side of the cathode conductive bodies for example plates, should be provided transversely to the magnetic line of force and the anode or anodes should be placed in a circ ar'yand symmetrical manner relatively to this axis about the cathode, these limiting bodies covering at least the projection of the cathode in the direction of the lines of force and being preferably arranged at such a mutual distance that approximately the minimum value of the arc-voltage as a function of this distance is obtained.
  • the experiments on which the present invention is based have revealed that this function exhibits a minimum.
  • anode or the anodes and the cathode prefferably be separated by a screen arranged within the anode or anodes, preferably in such manner that all straight lines which may be drawn between arbitrary points of the active surface of the cathode on the one hand and points of the surface of the anode on the other hand out the screen. It is thus possible for the blocking power of the tube to be increased to a considerable extent, since the particles originating from the cathode are prevented from reaching the anodes along a straight-line path.
  • This screening bush between the anode and the cathode must be made of non-magnetic material, or at least of a magnetic material which at the operating temperature attains a temperature above the Curie-point as a result of the heat production of the cathode.
  • a highly advantageous construction of the device according to the invention is obtained if the internal members of the tube between which a high potential difference, for example the blocking voltage of the tube, may occur, are so arranged that the length of the free electrostatic paths of the lines of force between the said members is not more than about the average free length of the electron path at the operating pressure of the tube. It is thus always ensured that the pd-value for the discharge path between the anode and the cathode is equal to a point of the break-down potential curve of Paschen which is located on the left of the minimum. As is wellknown, in this case a higher blocking voltage is obtained according as the electrode spacing is smaller so that the compactness of the construction is promoted.
  • one or more anodes be placed in a hollowcylindrical manner about the cathode and coaxialiy of the magnetic field and to cause them, jointly with the limiting bodies in which blocks of magnetic material are inserted on each side of the cathode, to constitute a box-shaped screening which contains, symmetrically relatively to the discharge space, the cathode screened radially relatively to the anode or anodes, this space being bounded on each side in the field direction by fiat planes, of which the front sides of the magnet blocks form part.
  • This construction offers the advantage that a highly compact discharge space is obtained which may be circumscribed on all sides by smooth surfaces, while the formation of free electrostatic paths of lines of force of excessive length is preliminarily avoided by the box-shaped character of the whole of screens and anode or anodes.
  • the cathode is separated from the anode by a screen, it is advantageous to construct this screen, preferably jointly with the limiting bodies, as a control member for the passage of the discharge.
  • Figs. 1, 2 and 3 show constructions of tubes to be used in devices according to the invention.
  • Fig. 1 shows schematically a converter tube comprising a discharge vessel .I, an incandescent cathode 2 and an anode 3 which are led to the exterior in a vacuum-tight manner in 4, 5 and B respectively.
  • a permanent magnet I with pole-pieces 8 and 9, arranged on each side of the discharge vessel I.
  • two limiting bodies I! and H are located at the height of these pole-pieces and traverse to the axis of the cylindrical anode 3, said limiting members being connected electrically and me- .chanically to the cathode.
  • the discharge Due to the action of the magnetic field, the discharge is concentrated in the cross-hatched region l2 which is constituted by projection of the cathode in the direction of the lines of force and bounded on each side by the bodies I! and ii.
  • the anode 3 is located very advantageously outside this concentrated part of the discharge with the result that low arc-voltages are obtained, while also the in tensity of the magnetic field of the anode has still a but low value and the blocking power of the tube is not appreciably decreased.
  • Fig. 2 shows a construction in which the anode is also arranged cylindrically about the cathode but is located in a magnetic field generated by blocks 22 and 23 of magnetic material with poles of the same sign, which are mounted symmetrically above and below the cathode in cylindrical box-shaped limiting members 24 and 25 which are co-axially arranged in the tube.
  • the cathode 24, too, is surrounded by a box-shaped screen 26 having axial apertures 21 and 28 whose section is so chosen that a sufiicient electrostatic screening of the cathode is obtained without involving an undesirable increase of the arc-voltage in the direction of passage.
  • the bodies 24, 25 and 26 are constructionally joined to each other and led to the exterior in 29, so that it is possible to use the whole as a control member for the tube.
  • the lower part of the body 25 is provided with an annular screen 30 which constitutes an obturation relatively to the glass wall which adjoins the anode cylinder 20 closed on top, the arrangement being such that electrostatic paths of lines of force of undesired length cannot extend freely between the terminal wires 3
  • This construction permits of obtaining a tube having an extremely high blocking powerwhich, in spite of the required low pressure of the gaseous or vapour atmosphere during operation, exhibits an excellent life of the cathode, since the arc-voltage in the direction of passage is very low in spite of the low pressure.
  • Fig. 3 shows schematically a tube of which like parts are provided with the reference numerals as in Fig. 1.
  • the discharge vessel l contains an incandescent cathode 2 whose supply wires are led to the exterior in 4 and 5, whereas the flat annular anode I5 is led to the exterior in 6 at the opposite end of the discharge vessel.
  • the magnets I6 are here located inside the discharge vessel I, coaxial and On each side symmetrical of the anode l5.
  • the direction of the magnetic lines of force is shown schematically, whereas the region having a field strength equal to naught is indicated by a dot-and-dash line.
  • the construction is so proportioned and arranged that the anode lies in a region where the field strength 1 is practically nil.
  • the diameter of the equator plane in which the field strength is nil has about the size of 2dx/2.
  • a cylindrical screen I! is arranged coaxially inside the anode I5, said screen separating the cathode in the radial direction from the anode and being placed at cathode potential. Due to this screen, the cathode “cannot see the anode so that the latter is screened in straight line from particles, for example of activating material, originating from the cathode.
  • An electron discharge device comprising a converter tube with a gaseous filling, an incandescent cathode in said tube and having a major axis, an electron emitting surface along said major axis of said cathode to emit electrons substantially perpendicularly to said emitting surface, means to establish a magnetic field transversely to said major axis of said cathode and having a part of said field passing through the said emitting surface in the direction of said electron emission, and an anode in said tube encircling said cathode and substantially symmetrically positioned with respect thereto and coaxially disposed about and outside of that part of the magnetic field which passes through the emitting surface of said cathode, said magnetic field having a strength such that approximately the minimum value of the arc voltage of the tube as a function of the field strength is obtained and the intensity of the field at the anode is within 5 gauss.
  • a device as claimed in claim 1 in which a magnet is disposed outside the discharge vessel of the tube the magnet having pole-shoes that are considerably smaller than the diameter of the discharge path and that are placed on each side thereof in line with the cathode.
  • a device as claimed in claim 2 in which the magnetic poles are smaller than the largest projection of the cathode in their direction.
  • a device as claimed in claim 2 in which the width of the active surface of the anode is larger than the smallest dimension of the transverse section of the magnet pole.
  • a device as claimed in claim 2 comprising conductive plates arranged on each side of the cathode transversely to the magnetic lines of force and the anode is placed in a circular manner and symmetrically relatively to this axis about the cathode, the conductive plates having a dimension transverse to the axisthat is sufficient to cover the projection of the cathode in the direction of the axis the lines of force and said plates being arranged at such a mutual distance that approximately the minimum value of the arc-voltage as a function of this distance is obtained.

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  • Plasma Technology (AREA)
US668548A 1941-04-11 1946-05-09 Magnetic field controlled gas filled discharge device Expired - Lifetime US2543702A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL239448X 1941-04-11

Publications (1)

Publication Number Publication Date
US2543702A true US2543702A (en) 1951-02-27

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ID=19780455

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Application Number Title Priority Date Filing Date
US668548A Expired - Lifetime US2543702A (en) 1941-04-11 1946-05-09 Magnetic field controlled gas filled discharge device

Country Status (6)

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US (1) US2543702A (en, 2012)
BE (1) BE445176A (en, 2012)
CH (1) CH239448A (en, 2012)
FR (1) FR881120A (en, 2012)
GB (1) GB632987A (en, 2012)
NL (1) NL60693C (en, 2012)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2640173A (en) * 1949-02-08 1953-05-26 Du Mont Allen B Lab Inc Suppression of spurious oscillations
US3032675A (en) * 1960-07-18 1962-05-01 Burroughs Corp Magnetron tube
DE1147697B (de) * 1960-11-22 1963-04-25 Csf Gasgefuellte Gleichrichterroehre

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB147856A (en) * 1916-12-23 1922-01-09 Walther Kossel Improvements in electric discharge tubes
US1558120A (en) * 1922-04-03 1925-10-20 Simpson Frederick Grant Radio receiving system
US1666858A (en) * 1926-05-27 1928-04-17 Jahn Augustus Henry Vacuum tube
US1791973A (en) * 1928-12-05 1931-02-10 Perryman Electric Co Inc Direction finder
US1807098A (en) * 1924-08-13 1931-05-26 Regan Safety Devices Co Inc Magnetron circuit controlling apparatus
US2116393A (en) * 1936-02-01 1938-05-03 Gen Electric Arc-back suppressor for electric discharge devices
DE660398C (de) * 1934-02-23 1938-05-21 Telefunken Gmbh Roehrenanordnung unter Verwendung eines durch Nebenschluss regelbaren permanenten Magneten
US2135006A (en) * 1936-04-21 1938-11-01 Philips Nv Rectifying device

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB147856A (en) * 1916-12-23 1922-01-09 Walther Kossel Improvements in electric discharge tubes
US1558120A (en) * 1922-04-03 1925-10-20 Simpson Frederick Grant Radio receiving system
US1807098A (en) * 1924-08-13 1931-05-26 Regan Safety Devices Co Inc Magnetron circuit controlling apparatus
US1666858A (en) * 1926-05-27 1928-04-17 Jahn Augustus Henry Vacuum tube
US1791973A (en) * 1928-12-05 1931-02-10 Perryman Electric Co Inc Direction finder
DE660398C (de) * 1934-02-23 1938-05-21 Telefunken Gmbh Roehrenanordnung unter Verwendung eines durch Nebenschluss regelbaren permanenten Magneten
US2116393A (en) * 1936-02-01 1938-05-03 Gen Electric Arc-back suppressor for electric discharge devices
US2135006A (en) * 1936-04-21 1938-11-01 Philips Nv Rectifying device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2640173A (en) * 1949-02-08 1953-05-26 Du Mont Allen B Lab Inc Suppression of spurious oscillations
US3032675A (en) * 1960-07-18 1962-05-01 Burroughs Corp Magnetron tube
DE1147697B (de) * 1960-11-22 1963-04-25 Csf Gasgefuellte Gleichrichterroehre

Also Published As

Publication number Publication date
GB632987A (en) 1949-12-05
NL60693C (en, 2012)
CH239448A (de) 1945-10-15
FR881120A (fr) 1943-04-15
BE445176A (en, 2012)

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