US3185883A - Non-microphonic tube construction - Google Patents

Non-microphonic tube construction Download PDF

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US3185883A
US3185883A US296631A US29663152A US3185883A US 3185883 A US3185883 A US 3185883A US 296631 A US296631 A US 296631A US 29663152 A US29663152 A US 29663152A US 3185883 A US3185883 A US 3185883A
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grid
anode
filament
electron
apertures
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US296631A
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Feinstein Lester
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GTE Sylvania Inc
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Sylvania Electric Products Inc
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J19/00—Details of vacuum tubes of the types covered by group H01J21/00
    • H01J19/42—Mounting, supporting, spacing, or insulating of electrodes or of electrode assemblies
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0001—Electrodes and electrode systems suitable for discharge tubes or lamps
    • H01J2893/0002—Construction arrangements of electrode systems
    • H01J2893/0005—Fixing of electrodes

Definitions

  • microphonism occurs due to structural weaknesses in the tube which give rise to variations in orientation or the spacing between the elements of the tube.
  • Microphonism may occur, for example, as a result of filament or cathode vibration which imparts a modulation to the electrons passing from the cathode to the anode of the tube as a result of displacement of all or a portion of the filament or cathode.
  • microphonism may occur as a result of vibration of the control grid structure which, in turn, modulates the electron stream and gives rise to unwanted noise output from the tube.
  • a third source of microphonism is in the anode itself which if it is not built with sufficient rigidity, may produce modulation of the elec tron stream due to variations in the current collected by the anode.
  • Microphonism may also be caused by several of the above eiiects operating together to produce varia tions in electrode spacing with consequent variation in output voltage.
  • An even further object of the invention is the provision of a filament structure for use in electron discharge devices which is accessible for easy assembly and adjustment and which is minimally responsive to vibration.
  • a further object of the invention is to provide a vacuum tube electrode mount which is extremely strong and is resistant to both bending and torsion forces.
  • a still further object is the reduction of grid-plate capacitance in tube structures having rugged elements.
  • a still further object is the reduction of electrode lead inductance.
  • FIG. 1 is a view in longitudinal cross-section of an electron discharge device embodying the invention.
  • FIG. 2 is a perspective view of the mount structure employed in the discharge device of FlG. 1.
  • a vacuum tube mount structure is contained within the cylindrical walls of glass envelope 2, and that connections are made to the electrodes in the mount by means of leads 4 projecting from and sealed through the wall of glass water base 6.
  • the mount structure within the envelope is supported in place by welding inner ends of leads 4 to exten- 3,l85,883 Patented May 25, 1965 sions of grid side rods 8 which are spaced to provide four rectangularly disposed side supports for grid 22.
  • Located near either end of grid 22 and extending transversely thereof are upper spacer disc 19 and lower spacer disc 11 which are made of an insulating materal such as mica. Spacer members it and 11 serve in turn to support anode side rods 12, tensioner support side rod 14, filament tie strips 16 and filament dampers 18.
  • anode side rods 12 support hollow rectangular anode 15 at the midpoints of the shorter sides of anode 15.
  • Anode side rods 12 are preferably welded to anode 15.
  • Grid 22 is also a hollow rectangular tube, preferably of conductive sheet material such as sheet metal, and is welded at its four corners to grid support rods 8.
  • Opposite faces 24 of grid 22 are provided with longitudinal rectangular apertures or slots 26 over which grid wires 28 are fastened.
  • grid wires 23 are spaced parallel to each other across the shortest dimension of grid aperture 26 and are fixed to faces 24 of grid 22 by Welding or other techniques commonly known in the art. The spacing of the grid wires and their diameter may be chosen according to well known principles to provide a given type of electrical characteristic by interstitially dividing the grid apertures 26 with conducting elements 28.
  • the electron source for the tube is filament 30 which is attached to lower mica 11 by means of filament anchoring strap 16 and passes through mica ll at wedge shaped openings 32.
  • the filament wire is retained in a position parallel to and centered adjacent to faces 24 of grid 22, passing through Wedge shaped opening 34 in upper mica l0 and over tensioning spring $6 at the upper end of the resulting filamentary configuration being generally U shape and disposed outwardly of the electrodes.
  • Filament tensioning spring 36 is provided with hook 355 to receive filament 3d and derives its support from horizontal pivot rod til, which, in turn, is supported at its center by tension support plate 42, the latter being welded to the upper end of tension support side rod 14. End loops 44 of filament support spring 36 are wound around pivot rod 40 and returned in the general direction of hook 38 to bear on ledges 46 of filament tensioning support plate 42. By this means spring 36 works against filament 3t) keeping it under tension.
  • Damping or stabilizing for filament 3% is provided along its active length by means of damping bars or elements 1% which are of a generally L-shaped configuration, one end of bar 18 being anchored in lower mica 11 and the horizontal portion of the bar extending generally parallel to face 24 of grid 22., and outwardly of filament 30 so as to exert a slight pressure thereon.
  • an insulating coating (not shown) of low heat conductivity is applied to the outer surfaces of filament damper rods 18 at their points of contact with filament fill. The location of the contact between dampers l8 and filament 3t and the force to be applied thereby will, of course, be determined by criteria already well known in the art and will ordinarily be accomplished at some point along the filament adjacent to the anode.
  • a typical design of the mount described above employs the following dimensions: spacing between filament 30 and face 24 of grid 22 is about .006 inch and between grid 24 and plate 15 about .815 inch. According to current design practice the effective area of the filament as projected on the grid is such that the filament is at the apex of a triangle, the opposite side of which is the Width of the plate, in this instance about .090 inch. Accordingly, with the spacings given above, the opening in the grid should be a minimum of .012 inch in width but,
  • the grid width may be as much as .030 inch.
  • the grid frame itself has a depth of about .135 inch and a Width on the slotted sides of about .155 inch, its length being determined by ordinary design considerations. is such a small portion of the total Width of face 24 of the grid member 22, it will be seen that the rigidity of Broadly speaking, thestrength of the grid frame varies as the ratio of the cube of the width of face 24 to the cube of the Width of slot 25. It should be noted, too, that the rectangular form of both grid 22 and anode 15 contributes substantially to the rigidity of these members, thus reducing any tendency of the members to contribute to microphonism in the final tube structure.
  • Vibration of the filament is minimized by utilizing the structure illustrated and by individually setting the tension up on each side of filament 39 by means of dampers 18 at the time of fabrication of the mount prior to its bly operation.
  • An electron discharge device having an envelope enclosing a rectangular anode, a rectangular grid of conductive sheet material surrounding said anode and having a number of electron apertures, and an electron source adjacent to said apertures, said grid including an elongated tubular portion of high strength to Weight ratio.
  • An electron discharge device having an envelope enclosing a rectangular anode, an elongated tubular grid of sheet conductive material rectangular in cross section and surrounding said anode, said grid having a number of longitudinally elongated electron apertures of a width substantially less than the width of the anode, and a number of electron sources adjacent to said apertures.
  • An electron discharge device having an envelope enclosing an apertured tubular grid, longitudinal support members extending from said grid and anchored to said envelope, an anode, a source of electrons, and transverse insulating members disposed at either end of said grid structure and supported thereby, said transverse members Inasmuch as the grid slot width.
  • An electron discharge device having an envelope enclosing a substantially rectangular tubular grid of conductive sheet material and having longitudinal apertures disposed at intervals around the periphery thereof, a substantially rectangular tubular anode, an electron source, a number of side rods fastened in corners of said grid and extending beyond the ends of said grid, and a pair of transverse insulating members supported by said side rods at either end of said grid and'projecting laterally with respect thereto, said transverse members supporting said anode centrally within said grid and supporting said electron source oppositesaid apertures in said grid.
  • An electron discharge device having a number of electrodes includin a. tubular grid, lateral supporting and insulating members supported by said grid, an anode supported within said grid by said insulating members, an envelope surrounding said electrodes, and lead-in conductors sealed through said envelope and projecting rigidly towards said electrode structure, said so-supported assembly being anchored against longitudinal motion to a number of said lead-in conductors.

Description

May 25, 1965 L. FEINSTEEN NON-MICROPHONIG TUBE CONSTRUCTION Filed July 1. 1952 6 0 44 0 W4 M 7 a 7 eu M 3m gr 4 7%; x
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INVENTOR LESTER FEINSTEIN BY lum/ ATTORNEY United States Patent 3,185,$83 NUN-MZCROPHONIC TUBE CGNSTRUETEGN Lester Feinstein, Bellerose, N352, assignor, by mesne assignments, to Sylvania Electric Products Inc, Wilmington, DeL, a corporation of Delaware Filed July 1, 1952, Ser. No. 296,631 8 (Jlaims. (Cl. 313-269) This invention relates to electron discharge devices and more specifically to improved structures for use in multielectrooe electron tubes.
In the design of vacuum or gas filled electron tubes a major concern has been the elimination of microphonism in the construction of the tube. The so-called microphonism occurs due to structural weaknesses in the tube which give rise to variations in orientation or the spacing between the elements of the tube. Microphonism may occur, for example, as a result of filament or cathode vibration which imparts a modulation to the electrons passing from the cathode to the anode of the tube as a result of displacement of all or a portion of the filament or cathode. Similarly, microphonism may occur as a result of vibration of the control grid structure which, in turn, modulates the electron stream and gives rise to unwanted noise output from the tube. A third source of microphonism is in the anode itself which if it is not built with sufficient rigidity, may produce modulation of the elec tron stream due to variations in the current collected by the anode. Microphonism may also be caused by several of the above eiiects operating together to produce varia tions in electrode spacing with consequent variation in output voltage.
It is an object of this invention to minimize microphonism in electron tube structures.
It is a further object of the invention to provide a rigid construction with a high strength-weight ratio.
It is a still further object of the invention to provide an improved electrode support or mount in an electron tube.
It is a still further object of the invention to provide an anode structure for an electron discharge device having a high strength to weight ratio.
An even further object of the invention is the provision of a filament structure for use in electron discharge devices which is accessible for easy assembly and adjustment and which is minimally responsive to vibration.
A further object of the invention is to provide a vacuum tube electrode mount which is extremely strong and is resistant to both bending and torsion forces.
A still further object is the reduction of grid-plate capacitance in tube structures having rugged elements.
A still further object is the reduction of electrode lead inductance.
The above objects and others, which will appear as a result of consideration of the drawings and below appended description of the invention, are achieved by providing a vacuum tube mount structure employing a centrally located anode surrounded by one or more grids, and having an outwardly disposed cathode or filament. A preferred embodiment of the invention is illustrated in the drawings in which:
FIG. 1 is a view in longitudinal cross-section of an electron discharge device embodying the invention.
FIG. 2 is a perspective view of the mount structure employed in the discharge device of FlG. 1.
Referring now to FIG. 1, it will be seen that a vacuum tube mount structure is contained Within the cylindrical walls of glass envelope 2, and that connections are made to the electrodes in the mount by means of leads 4 projecting from and sealed through the wall of glass water base 6. The mount structure within the envelope is supported in place by welding inner ends of leads 4 to exten- 3,l85,883 Patented May 25, 1965 sions of grid side rods 8 which are spaced to provide four rectangularly disposed side supports for grid 22. Located near either end of grid 22 and extending transversely thereof are upper spacer disc 19 and lower spacer disc 11 which are made of an insulating materal such as mica. Spacer members it and 11 serve in turn to support anode side rods 12, tensioner support side rod 14, filament tie strips 16 and filament dampers 18.
Referring now to FIG. 2, in which the numerals used in FIG. 1 denurnerate the same parts, it will be seen that anode side rods 12 support hollow rectangular anode 15 at the midpoints of the shorter sides of anode 15. Anode side rods 12 are preferably welded to anode 15. Grid 22 is also a hollow rectangular tube, preferably of conductive sheet material such as sheet metal, and is welded at its four corners to grid support rods 8. Opposite faces 24 of grid 22 are provided with longitudinal rectangular apertures or slots 26 over which grid wires 28 are fastened. In the preferred embodiment of the invention, grid wires 23 are spaced parallel to each other across the shortest dimension of grid aperture 26 and are fixed to faces 24 of grid 22 by Welding or other techniques commonly known in the art. The spacing of the grid wires and their diameter may be chosen according to well known principles to provide a given type of electrical characteristic by interstitially dividing the grid apertures 26 with conducting elements 28.
The electron source for the tube is filament 30 which is attached to lower mica 11 by means of filament anchoring strap 16 and passes through mica ll at wedge shaped openings 32. The filament wire is retained in a position parallel to and centered adjacent to faces 24 of grid 22, passing through Wedge shaped opening 34 in upper mica l0 and over tensioning spring $6 at the upper end of the resulting filamentary configuration being generally U shape and disposed outwardly of the electrodes. Filament tensioning spring 36 is provided with hook 355 to receive filament 3d and derives its support from horizontal pivot rod til, which, in turn, is supported at its center by tension support plate 42, the latter being welded to the upper end of tension support side rod 14. End loops 44 of filament support spring 36 are wound around pivot rod 40 and returned in the general direction of hook 38 to bear on ledges 46 of filament tensioning support plate 42. By this means spring 36 works against filament 3t) keeping it under tension.
Damping or stabilizing for filament 3% is provided along its active length by means of damping bars or elements 1% which are of a generally L-shaped configuration, one end of bar 18 being anchored in lower mica 11 and the horizontal portion of the bar extending generally parallel to face 24 of grid 22., and outwardly of filament 30 so as to exert a slight pressure thereon. In order to minimize heat losses, an insulating coating (not shown) of low heat conductivity is applied to the outer surfaces of filament damper rods 18 at their points of contact with filament fill. The location of the contact between dampers l8 and filament 3t and the force to be applied thereby will, of course, be determined by criteria already well known in the art and will ordinarily be accomplished at some point along the filament adjacent to the anode.
A typical design of the mount described above employs the following dimensions: spacing between filament 30 and face 24 of grid 22 is about .006 inch and between grid 24 and plate 15 about .815 inch. According to current design practice the effective area of the filament as projected on the grid is such that the filament is at the apex of a triangle, the opposite side of which is the Width of the plate, in this instance about .090 inch. Accordingly, with the spacings given above, the opening in the grid should be a minimum of .012 inch in width but,
'the grid structure is considerably enhanced.
in order to allow for fringe etfects, the grid width may be as much as .030 inch. The grid frame itself has a depth of about .135 inch and a Width on the slotted sides of about .155 inch, its length being determined by ordinary design considerations. is such a small portion of the total Width of face 24 of the grid member 22, it will be seen that the rigidity of Broadly speaking, thestrength of the grid frame varies as the ratio of the cube of the width of face 24 to the cube of the Width of slot 25. It should be noted, too, that the rectangular form of both grid 22 and anode 15 contributes substantially to the rigidity of these members, thus reducing any tendency of the members to contribute to microphonism in the final tube structure.
Vibration of the filament is minimized by utilizing the structure illustrated and by individually setting the tension up on each side of filament 39 by means of dampers 18 at the time of fabrication of the mount prior to its bly operation.
It will be apparent to the reader that many changes I may be made to the detail of the structural principles employed Without deviating from the spirit of the invention. For example, the use of other types of apertures than the slot in the grid may be desirable, as Well as other configurations than rectangular for the grid and anode bodies. Similarly, the anode and grid extensions which traverse the insulating spacer members may be made integral with those electrodes, rather than as side rods as here shown.
For the above reason it is desired that the below appended claims be construed in keeping with the spirit of the invention rather than limited to the illustrative embodiment detailed above.
What I claim is:
1. An electron discharge device having an envelope enclosing a rectangular anode, a rectangular grid of conductive sheet material surrounding said anode and having a number of electron apertures, and an electron source adjacent to said apertures, said grid including an elongated tubular portion of high strength to Weight ratio.
2. An electron discharge device having an envelope enclosing a rectangular anode, an elongated tubular grid of sheet conductive material rectangular in cross section and surrounding said anode, said grid having a number of longitudinally elongated electron apertures of a width substantially less than the width of the anode, and a number of electron sources adjacent to said apertures.
3. An electron discharge device having an envelope enclosing an apertured tubular grid, longitudinal support members extending from said grid and anchored to said envelope, an anode, a source of electrons, and transverse insulating members disposed at either end of said grid structure and supported thereby, said transverse members Inasmuch as the grid slot width.
longitudinally supporting said anode member within said grid structure and said electron source on the side of said grid member away from said anode member.
4. An electron discharge device having an envelope enclosing a substantially rectangular tubular grid of conductive sheet material and having longitudinal apertures disposed at intervals around the periphery thereof, a substantially rectangular tubular anode, an electron source, a number of side rods fastened in corners of said grid and extending beyond the ends of said grid, and a pair of transverse insulating members supported by said side rods at either end of said grid and'projecting laterally with respect thereto, said transverse members supporting said anode centrally within said grid and supporting said electron source oppositesaid apertures in said grid.
5. The discharge device of claim 4 in which a pair of said longitudinal apertures are oppositely located on said anode and said electron source is a substantially U-shaped filament each leg of which passes adjacent to one of said apertures.
6. The discharge device of claim 4 in which said longitudinal apertures are divided into groups of smaller apertures by a number of conducting elements placed thereacross. V
7. The discharge device of claim 4 in. which said transverse members have openings near either extremity and said electron source comprises a filament passing through said openings and maintained thereby in spaced relation adjacent said aperture.
8. An electron discharge device having a number of electrodes includin a. tubular grid, lateral supporting and insulating members supported by said grid, an anode supported within said grid by said insulating members, an envelope surrounding said electrodes, and lead-in conductors sealed through said envelope and projecting rigidly towards said electrode structure, said so-supported assembly being anchored against longitudinal motion to a number of said lead-in conductors.
References Cited hythe Examiner UNITED STATES PATENTS DAVID J. GALVIN, Primary Examiner.
RALPH G. NILSGN, ELI I. SAX, JAMES L. BREWRINK, CHESTER L. IUSTUS, Examiners.

Claims (1)

1. AN ELECTRON DISCHARGE DEVICE HAVING AN ENVELOPE ENCLOSING A RECTANGULAR ANODE, A RECTANGULAR GRID OF CONDUCTIVE SHEET MATERIAL SURROUNDING SAID ANODE AND HAVING A NUMBER OF ELECTRODE APERTURES, AND AN ELECTRON SOURCE ADJACENT TO SAID APERTURES, SAID GRID INCLUDING AN ELONGATED TUBULAR PORTION OF HIGH STRENGTH TO WEIGHT RATIO.
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Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1128280A (en) * 1914-06-08 1915-02-16 Western Electric Co Thermionic detector.
US1128279A (en) * 1914-05-16 1915-02-16 Western Electric Co Electric-wave amplifier.
US1558111A (en) * 1925-03-23 1925-10-20 Magnavox Co Vacuum tube
US1978918A (en) * 1931-06-22 1934-10-30 Frederick E Terman Thermionic tube
US2050383A (en) * 1931-12-04 1936-08-11 Westinghouse Electric & Mfg Co Electric discharge device
US2213551A (en) * 1937-03-27 1940-09-03 Rca Corp Electron discharge device
US2303277A (en) * 1941-06-13 1942-11-24 Sylvania Electric Prod Antimicrophonic filament
US2350003A (en) * 1940-07-17 1944-05-30 Bell Telephone Labor Inc Electron discharge device
US2413006A (en) * 1941-12-17 1946-12-24 Raytheon Mfg Co Electrode assembly for discharge tubes

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1128279A (en) * 1914-05-16 1915-02-16 Western Electric Co Electric-wave amplifier.
US1128280A (en) * 1914-06-08 1915-02-16 Western Electric Co Thermionic detector.
US1558111A (en) * 1925-03-23 1925-10-20 Magnavox Co Vacuum tube
US1978918A (en) * 1931-06-22 1934-10-30 Frederick E Terman Thermionic tube
US2050383A (en) * 1931-12-04 1936-08-11 Westinghouse Electric & Mfg Co Electric discharge device
US2213551A (en) * 1937-03-27 1940-09-03 Rca Corp Electron discharge device
US2350003A (en) * 1940-07-17 1944-05-30 Bell Telephone Labor Inc Electron discharge device
US2303277A (en) * 1941-06-13 1942-11-24 Sylvania Electric Prod Antimicrophonic filament
US2413006A (en) * 1941-12-17 1946-12-24 Raytheon Mfg Co Electrode assembly for discharge tubes

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