US2772939A - Manufacture of traveling wave tubes - Google Patents

Manufacture of traveling wave tubes Download PDF

Info

Publication number
US2772939A
US2772939A US387362A US38736253A US2772939A US 2772939 A US2772939 A US 2772939A US 387362 A US387362 A US 387362A US 38736253 A US38736253 A US 38736253A US 2772939 A US2772939 A US 2772939A
Authority
US
United States
Prior art keywords
helix
glass
envelope
collapse
tube
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
Application number
US387362A
Other languages
English (en)
Inventor
Joseph P Laico
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to NL96518D priority Critical patent/NL96518C/xx
Priority to NL190364D priority patent/NL190364A/xx
Priority to BE532397D priority patent/BE532397A/xx
Priority to DENDAT1068389D priority patent/DE1068389B/de
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US387362A priority patent/US2772939A/en
Priority to FR1107766D priority patent/FR1107766A/fr
Priority to GB30211/54A priority patent/GB763545A/en
Application granted granted Critical
Publication of US2772939A publication Critical patent/US2772939A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/34—Travelling-wave tubes; Tubes in which a travelling wave is simulated at spaced gaps
    • H01J25/36—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and without magnet system producing an H-field crossing the E-field
    • H01J25/38—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and without magnet system producing an H-field crossing the E-field the forward travelling wave being utilised
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/16—Circuit elements, having distributed capacitance and inductance, structurally associated with the tube and interacting with the discharge
    • H01J23/24—Slow-wave structures, e.g. delay systems
    • H01J23/26—Helical slow-wave structures; Adjustment therefor

Definitions

  • traveling wave tubes having .very small helices for operationat frequencies of the order of thousands of megacycles, such as in the range of 4,000 to 11,000 megacycles or higher exhibit a fading of output power after the tube had been 4operated for a few minutes.
  • This power fade is caused by increase in the resistive loss on the helix above that intrinsic to the ⁇ helix and the attenuation deposited thereon. This increase results from heating of helix due mainly to radio frequency power traveling along the helix transmission line in excess of the transmission capacity of the helix. This excess power on the transmission line occurs adjacent the output end as the radio frequency voltage and power on the helix increase exponentially along the helix.
  • the glass envelope be collapsed onto the helix support rods only adjacent the output end and that it not be in contact at any point with the wires of the helix itself extending between support rods, as discussed in the above-mentioned application.
  • a helix mounted on helix support rods is slid into an elongated glass envelope portion to make a close t therewith.
  • a continuous current pathf is provided through the helix when positioned in the traveling wave tubefby a lead electrically connecting the input end of the helix to one of the thermal pins in lthe base of the tube and a fuse wire electrically connecting the output end of the helix to the, electron collector of the traveling wave tube.
  • a reflecting cylinder ⁇ is positioned around the glass to give the additional temperature rise needed to soften the glass suiciently to allow the pressure differential to deform it and collapse it onto the support rods.
  • the heat reflecting cylinder may be long enough to deform the entire length desired or may be moved along the helix to attain any desired lengthof collapse of the glass envelope.
  • the envelope When the helix has been outgassed, the envelope is evacuated, a short high current ⁇ passed through the helix to burn out the fuse that provided the continuous current connection from the helix to the electron collector and It is a further feature of this invention that a current be passed through the helix during the manufacture of t a traveling wave tube to heat the helix and the glass envelope encompassing the helix, that the envelope be evacuated, and that a heat reflecting cylinderbe positioned around the glass envelope adjacent the portion to be collapsed onto the helix support rods to provide the additionalheat necessary to soften the glass sufficiently to allow collapse underthe differential pressure existing on the'glass envelope.
  • the helix of a traveling wave tube be outgassed by passing a current through the helix and a path including a fuse wire within the traveling wave tube and that the fuse wire be burned out following the outgassing the helix.
  • Fig. l is an external view of a traveling wave tube having a portion of the elongated vglass envelope collapsed onto the helix support rods;
  • Fig. 2 is a sectional view of the tube of Fig. l showing the tube in the process of manufacture after the glass envelope portion has been collapsed but before the helix fuse wire has been ruptured;
  • Fig. ⁇ 3 is asecti-onal view of the helix and collapsed envelope portion tak-en along the line 3-3 of Fig. 1;
  • Fig. 4 is azschematic representation of the circuit and equipment employed in the collapsing of the glass envelope in accordance with an aspect of this invention.
  • Fig. 5 is an enlarged sectional view of the output end of the helix support rods and the electron collector showing particularly the fuse wire connecting the helix and the electron 'collector during the manufacture of the traveling wave tube in accordance with the processes of this invention.
  • Fig. 1 is an external side viewgof aV travelingwave tube having a portion ofthe elongated glass tubing 10 between the electron gun assem-1 Patented Dec. 4, 1,956
  • the electron gun assembly 11 may be of any known type; however, for reasons set ⁇ forth below, a current path is provided from the helix 15 through the gun assembly to one of the terminal pins 17 in the base of the assembly.
  • the particular gun depicted in'Fig. 2 comprises a plurality of electrodes 18 which are mounted by support pins 22 which extend through apertures 20 in the insulating ring 21. These electrodes are positioned coaxally by a mandrel, not shown, which assures proper alignment of the parts.
  • an insulating ring 26 is interposed between the electron collector cylinder 27 and an inner support ring 28 bonded to the inner surfaces of the support rods.
  • the cathode 25 of the gun is then positioned in the gun and helix assembly, appropriate connections made to the bore pins, the bore sealedto one end of Athe tube envelope and the collector assembly to the other end of the tube envelope.
  • a fuse Wise 30 is initially connected between the collector cylinder 27 and the ring 28 towhich the helix is electrically connected.
  • a direct current path at this time through the tube comprising one of the terminal pins 17, a lead 31 connecting this pin to the aligning tube 24, the helix 15, ring 28, fusewire 30, and collector cylinder27.
  • a current is passed through this path which is shown in Fig. 4 as being closed by a conductor 32, a switch 33, and a battery or voltage source 34.
  • the envelope of the tube is exhausted, as by a vacuum pump 36 connected by rubber tubing 37 to the collector cylinder 27.
  • the heat generated by the current in the helix is sufcient to soften the glass of the envelope 10 but not to the point where the glass will collapse under the pressure dilerential existing between the atmosphere and the evacuated envelope.
  • a heat retiecting cylinder 40 having a bright inner surface is placed around the envelope at a point where it is desired to collapse the glass. The heat reflected back upon the glass by the cylinder 40 is then suicient to give the additional temperature rise needed to soften the glass to allow the atmospheric pressure to collapse the glass onto the helix support rods 14.
  • the total distance of this collapse is very slight, being of the order of less than a mil as the helix support rods are preferably slid into the envelope y10 with a close Vtit. It is, therefore, important that the amount of heat and the collapse of the glass be carefully controlled to prevent too great a collapse which would result in the glass being in contact with the helix'itself.
  • the glass if the glass is contiguous to the helix, it provides a low dielectric path for the electromagnetic energy on the helix. Energy is vthen shunted through this path instead of passing through the center of the helix where interaction of the electromagnetic wave energy and the electric beam is attained. When the glass is in contact with the helix, the degree of coupling and the eiciency of the tube are, therefore, reduced.
  • thermocouple 42 within the reflector 40 and preferably in contact with the envelope 10.
  • the leads of the thermocouple may be brought out through apertures in the reflector 40 and connected to a suitable meter or indicating device 43.
  • the ends of the reflecting cylinder 40 are partially closed further to confine the heat to the desired area of collapse.
  • the reflecting cylinder 40 may be of sucient length to collapse the entire portion of the glass envelope desired to be collapsed or may be smaller and be moved along the envelope to collapse successive parts of the envelope.
  • the rellecting cylinder 40 is removed and, in accordance with another aspect of this invention, a current is passed through the direct current path identitied above and best seen in Fig. 4.
  • This current serves to outgas the helix.
  • Priorly helices have been heated by inductive coupling to a high frequency generator. This technique however has not only been awkward and inetticient, but has been exceedingly difficult t-o control resulting in a large number of rejected tubes.
  • By passing a direct current through the helix itself outgassing of the helix can be attained with very accurate control on the heating of the helix and damage to the helix or the tube during this outgassing can, therefore, be prevented.
  • the fuse wire 30 is burnt out by application of a short high current to the helix, and the current path through the tube is removed.
  • the lead 31 and terminal pin 17 to which it is connected may be utilized during the operation of the tube for applying a direct current voltage to the helix, as is known in the art, or may be unconnected in the operating circuit.
  • the tube envelope is then sealed, as by closing olf the open end of the collector cylinder 27.
  • the outgassing occurs after the collapsing of the portion of the glass envelope
  • the order in which these two steps of the process -occur is not important and that the helix may advantageously be outgassed rst.
  • the outgassing current is applied to the helix while the envelope is being evacuated but before the reflecting cylinder has been placed around the envelope. After a suicient time for outgassing the reflecting cylinder is positioned around the envelope without interrupting the current or removing the tube from the pump, and the glass collapsed. Following this the current is removed, the tube sealed, and the fuse wire ruptured, as described above.
  • an outgassing current of 2.89 ampercs is applied to the helix for about 30 minutes, raising the temperature of the helix to about 760 C. throughout the entire length of the helix.
  • the heat reliector was then positioned laround the helix and the same current employed for collapsing the glass onto the helix.
  • the heat reflector raises the temperature of the glass envelope to about 625 C., and the collapse occurs in about 1A minute.
  • the current was then turned oif, the helix cooled to room temperature and a current of approximately 4 amperes appliedy to the helix to rupture or burn out the fuse wire 30, which was a 0.006 inch platinum wire, though other fuse wires known in the art may be employed.
  • the tube is then sealed.

Landscapes

  • Microwave Tubes (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
US387362A 1953-10-21 1953-10-21 Manufacture of traveling wave tubes Expired - Lifetime US2772939A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
NL96518D NL96518C (nl) 1953-10-21
NL190364D NL190364A (nl) 1953-10-21
BE532397D BE532397A (nl) 1953-10-21
DENDAT1068389D DE1068389B (nl) 1953-10-21
US387362A US2772939A (en) 1953-10-21 1953-10-21 Manufacture of traveling wave tubes
FR1107766D FR1107766A (fr) 1953-10-21 1954-06-29 Tubes à ondes progressives et leur procédé de fabrication
GB30211/54A GB763545A (en) 1953-10-21 1954-10-20 Improvements in or relating to travelling wave tubes and the manufacture thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US387362A US2772939A (en) 1953-10-21 1953-10-21 Manufacture of traveling wave tubes

Publications (1)

Publication Number Publication Date
US2772939A true US2772939A (en) 1956-12-04

Family

ID=23529549

Family Applications (1)

Application Number Title Priority Date Filing Date
US387362A Expired - Lifetime US2772939A (en) 1953-10-21 1953-10-21 Manufacture of traveling wave tubes

Country Status (6)

Country Link
US (1) US2772939A (nl)
BE (1) BE532397A (nl)
DE (1) DE1068389B (nl)
FR (1) FR1107766A (nl)
GB (1) GB763545A (nl)
NL (2) NL190364A (nl)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2956373A (en) * 1957-04-30 1960-10-18 Rca Corp Glass bulb fabrication
US3309187A (en) * 1963-12-30 1967-03-14 Westinghouse Electric Corp Method of reshaping fabricated infrared-generating devices such as electric lamps and the like
DE1262469B (de) * 1963-12-30 1968-03-07 Westinghouse Electric Corp Verfahren zum Herstellen eines rohrfoermigen, gekruemmten elektrischen Infrarotstrahlers mit durch Verschmelzen verschlossenem glaesernem Gefaess
US4514206A (en) * 1983-04-11 1985-04-30 Veb Kombinat Feinmechanische Werke Halle Method for the production of a transverse corrugated or serrated interior pipe of a double-walled special gas discharge pipe with high angle selectivity

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US832302A (en) * 1903-06-12 1906-10-02 Gen Electric Method of sealing metal into glass or other vitreous material.
GB476488A (en) * 1936-06-05 1937-12-06 Gen Electric Co Ltd Improvements in the sealing of electric conductors into quartz envelopes
US2651100A (en) * 1949-04-29 1953-09-08 Hunt Capacitors Ltd A Manufacture of electrical capacitors
US2671873A (en) * 1951-09-06 1954-03-09 Wilber L Meier Cold cathode discharge device and method of manufacture

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB664663A (en) * 1949-09-01 1952-01-09 Mullard Radio Valve Co Ltd Improvements in travelling wave tubes
GB707123A (en) * 1952-04-29 1954-04-14 English Electric Valve Co Ltd Improvements in or relating to travelling wave tubes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US832302A (en) * 1903-06-12 1906-10-02 Gen Electric Method of sealing metal into glass or other vitreous material.
GB476488A (en) * 1936-06-05 1937-12-06 Gen Electric Co Ltd Improvements in the sealing of electric conductors into quartz envelopes
US2651100A (en) * 1949-04-29 1953-09-08 Hunt Capacitors Ltd A Manufacture of electrical capacitors
US2671873A (en) * 1951-09-06 1954-03-09 Wilber L Meier Cold cathode discharge device and method of manufacture

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2956373A (en) * 1957-04-30 1960-10-18 Rca Corp Glass bulb fabrication
US3309187A (en) * 1963-12-30 1967-03-14 Westinghouse Electric Corp Method of reshaping fabricated infrared-generating devices such as electric lamps and the like
DE1262469B (de) * 1963-12-30 1968-03-07 Westinghouse Electric Corp Verfahren zum Herstellen eines rohrfoermigen, gekruemmten elektrischen Infrarotstrahlers mit durch Verschmelzen verschlossenem glaesernem Gefaess
US4514206A (en) * 1983-04-11 1985-04-30 Veb Kombinat Feinmechanische Werke Halle Method for the production of a transverse corrugated or serrated interior pipe of a double-walled special gas discharge pipe with high angle selectivity

Also Published As

Publication number Publication date
BE532397A (nl)
NL96518C (nl)
GB763545A (en) 1956-12-12
FR1107766A (fr) 1956-01-05
DE1068389B (nl) 1959-11-05
NL190364A (nl)

Similar Documents

Publication Publication Date Title
US2125316A (en) Method of forming glass to metal seals
US2353743A (en) High-frequency electronic discharge device
US2413689A (en) Electron discharge device
US2445993A (en) Cathode structure
US2788465A (en) Traveling wave electron discharge device
US2226653A (en) Electromagnetic oscillation apparatus
US3271615A (en) Traveling wave electron discharge device having means exerting a radial force upon the envelope
US2544664A (en) High-frequency high-power tube
US2772939A (en) Manufacture of traveling wave tubes
US2418117A (en) Electron discharge device
US2765421A (en) Electron discharge devices
US2682009A (en) Seal and method of fabrication
US2494693A (en) Electron discharge device
US2408238A (en) Space discharge device
US2458802A (en) Magnetron assembly and method
US2123015A (en) Seal for discharge lamps
US2527587A (en) Electron discharge device
USRE15278E (en) Electron-discharge apparatus
US2808533A (en) Electron discharge devices
US2500355A (en) Electron discharge tube
US2412997A (en) Electron discharge device
US2553425A (en) Electron discharge device of the magnetron type
US2565387A (en) Interdigital magnetron
US2428609A (en) High-frequency electric discharge device
US2236859A (en) Getter for electron discharge devices