US2452861A - Current converting tube - Google Patents

Current converting tube Download PDF

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Publication number
US2452861A
US2452861A US731289A US73128947A US2452861A US 2452861 A US2452861 A US 2452861A US 731289 A US731289 A US 731289A US 73128947 A US73128947 A US 73128947A US 2452861 A US2452861 A US 2452861A
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US
United States
Prior art keywords
anode
cathode
tube
screening
discharge
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
US731289A
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English (en)
Inventor
Mulder Johannes Gijsbe Wilhelm
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.)
Hartford National Bank and Trust Co
Original Assignee
Hartford National Bank and Trust Co
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
Application filed by Hartford National Bank and Trust Co filed Critical Hartford National Bank and Trust Co
Application granted granted Critical
Publication of US2452861A publication Critical patent/US2452861A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/02—Details
    • H01J17/04—Electrodes; Screens
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
    • H01J5/32—Seals for leading-in conductors
    • H01J5/40—End-disc seals, e.g. flat header
    • H01J5/42—End-disc seals, e.g. flat header using intermediate part
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0033—Vacuum connection techniques applicable to discharge tubes and lamps
    • H01J2893/0034—Lamp bases

Definitions

  • This invention relates to a current converting tube which in a common vessel contains an oxide cathode, one or more anodes and a gas and/or vapour filling having a pressure of more than 0.3 mm. of mercury at operating temperatures and in which the effective anode supply voltage exceeds 100 volts and the rectified current is at least amps.
  • tubes have also been developed in which the cathode and the anode are housed in a common vessel without anode arms and in this case the freedom from back stroke aimed at is endeavoured to be ensured by the interposition of screens only.
  • higher operating voltages for example of more than 100 volts effective anode supply voltage with a rectified current of more than 10 amps. were proceeded with it was found impossible to obtain the freedom from back-arcing aimed at at an operating pressure of the tube of 0.3 mm. or even more. It would therefore have been necessary to tolerate the shorter life of the tube which is consequent upon a lower pressur at which the gas filling is sooner bound by the disintegrated material of the electrodes. It has thus always been necessary in the industry tolook for a compromise between freedom from back-fire on the one hand and life on the other hand and it was impossible to realise both properties at a time in the mannerv here desired.
  • the invention has for its object to ensure that current converting tubes which are suitable for the loads hereinbefore mentioned or even higher loads are free from back-fire under all conditions so that in view of the chosen pressure of more than 0.3 mm. mercury a fair length of life is ensured at any time.
  • Screens surrounding anode or cathode of the tube are known per se but only the use of the criterion of the invention has been found to permit of constructing the screening of both the anode and the cathode in such manner that the reliability of service and length of life of the tube aimed at are not achieved at the expense of other properties of the tube, such for example as low losses in the discharge path and simple construction of the discharge vessel.
  • a particularly suitable operating condition for the use of the criterion of the invention is constituted by the heating-up period of the cathode. Assuming the tube to be in normal use a reduction in the filament supply voltage, particularly if brought about slowly, does not always result in a particular tendency to back-stroke, because in this case a condition may ensue under which a smaller part of the cathode evolves the emission at a higher temperature. If, however, the tube is switched into a circuit in which at full anode voltage the full operating current will occur as soon as the cathode delivers the emission current required therefor conditions appear during the heating-up period under which the tendency to back-fire increases to a marked extent.
  • the temperature range between ordinary and operating temperature is traversed slowly, a zone being passed through in which the cathode readily sputters and thus is apt to initiate a back-fire.
  • a highly sensitive test is obtained by even retarding this heating up, for example by applying a filament supply voltage of 50% of the normal value and connecting the tube into circuit at a normal anode voltage and current limitation. The period in which sputtering may occur is thus traversed particularly slowly.
  • the screens surrounding cathode and anode may advantageously be constructed and arranged in such manner that the speed at which the particles proceeding from the cathode f3 leave the cathode does not contain a com ponent in a direction towards an anode, even after one reflection against an internal part of the tube, the screening of the anode being on the other hand constructed and arranged so as to ensure that any particles that may proceed from the cathode or discharge cannot reach the anode.
  • anode screen it is advantageous to provide the anode, except for the active surface situated at the front side, with a screening, preferablyconductive, which complete- 1y screens both the inactive surface and the pole wire of the anode, the union between pole screening and surrounding tube wall being formed Without any jars, for example by sealing.
  • a tube thus rendered freefrom back-fire may present the disadvantage that irregularities in the starting-up voltage of the main discharge in the positive phase occur due to the fact that there is no suificient ionisation of the entire main discharge path at the moment of; starting of the discharge in'the positive phase, particularly in those parts which are immediately adjacent the anode and are screened by the cathode screen in a highly efiective manner from the active surface of the cathode.
  • Figs. 1 and 2 are sectional views of current converting tubes according to the invention constructed respectively in metal and with one anode and in glass and with two anodes.
  • the tube shown in Fig. 1 has'a discharge vessel comprising a substantially cylindrical metal part I to which glass parts-2 and 3 are sealed so as to enable a vacuum to be obtained;
  • the glass part 3 comprises two re-entrant parts 22 having sealed, to it: small metal hoods. 4- :for example of ferrochrome, which'in turn support the pole wires 5 of 9. directly heated incandescent cathode 6, supply leads i being welded to the hoods- 4 on the outside.
  • the glass part 2. similarly carries a pole wire 8 for the anoded-which pole'wire is pr vided with a binding post In.
  • the pole wires 5" and 8 are surrounded by screening tubes. H and l2-respectively of ceramic.
  • the glass part 2 isunited, by sealing, without any jar to the ceramic tube l2 so that the discharge has no opportunity of pressing through along this path to the pole wire 8 of the anode 9. It is particularly convenientto keep the space at the back of the anode free from ionisation; this purpose is served by a labyrinth which comprises a circular plate [5 and a diaphragm it with the result that the space at the back of the anode is efiectively screened from the discharge of the tube.
  • the incandescent cathode 6 and the anode 9 are separated by a further labyrinth which is constituted by a diaphragm l1 and an ovalshaped disc ill, the latter being arranged with its largest lengthalong the axis of the incandescent cathode 6,
  • the discharge is thus forced to follow a curved path between the said electrodes and there is such a screening between them in a straight line that backfires are largely rendered difiicult.
  • the manner in which in the tube described the anode is screened both from the surrounding dischargespace and from the oathode is so effective-that the tube satisfies the criterion of the invention, i.
  • the discharge vessel contains an.
  • the tube shown in Fig. 2 has a glass discharge vessel 3
  • a cathode 32 and-two anodes 33 are similarly arranged by means of pole wires 34 and 35 which by means of small ferroch-rome hoods 36 and 3-1 are sealed'in the ends of the. tube so as to ensure a vacuum to be obtained.
  • the cathode is surrounded by a cylindrical cathode screen 44 which on the underside is closed by a base-plate 45 and is secured to the pole-screening tubes 450i the cathode, whilst. the aperture of the cathode screen is screened in the. direction of the anodes by a circular plate 41' having an arcuate edge 48. which leaves free an annular slit through which the discharge between cathode and anode is allowed to emerge, whereas par-v ticles proceeding from the cathode can only emerge'in a direction remote fromthe anodeand even afterreflection on the wall of the dis charge vessel retain, a direction which is remote from the anodes 33.
  • the construction of'this tube renders it. desirable to form starting-up apertures 49* in the plate 4:! in: order to ensure reliable starting-up in the positive: phase.
  • The, tube is filled with argon at a pressure of 0.7 mm. of mercury and in addition contains liquid mercury'zil! atithexbottom'. Under certain conditions.
  • This tube also meets the requirement of the invention that at an abnormally low cathode temperature a back stroke does not occur and practice has shown that when the tube is in continuous use the freedom from back stroke is conserved under all conditions.
  • tubes of known screen construction the cathode, after an operating time of 1000 running-hours, used to lose its quality appreciably by disintegration or by poisoning by anode material, experiments conducted with tubes according to the invention revealed that the activated surface of the cathode had practically not changed even after normal operation for 2500 hours.
  • a rectifier tube particularly for service in circuits involving potentials in excess of 100 volts and currents in excess of amperes, comprising an envelope and within said envelope a gaseous filling at a pressure in excess of 0.3 millimeter of mercury, an oxide cathode, an anode having an active surface and an inactive surface, a first screening member surrounding the inactive surface of said anode, and a second screening mem ber interposed between said cathode and the active surface of said anode, said screening members being so cooperatively arranged with respect to said cathode and said anode that electrons emitted from said cathode are prevented from directly passing to the active surface of said anode thereby preventing arc-back at lower than normal cathode temperatures.
  • a rectifier tube particularly for service in circuits involving potentials in excess of 100 volts and currents in excess of 10 amperes, comprising an envelope and within said envelope a gaseous filling at a pressure in excess of 0.3 millimeter of mercury, an oxide cathode, an anode having an active surface and an inactive surface, a screening member surrounding the inactive surface of said anode, and a second screening member interposed between said cathode and the active surface of said anode, said screening members being so cooperatively arranged that arc-back is prevented upon application of normal anode voltage at normal anode currents at filament voltages in excess of onehalf of normal filament voltage.
  • a rectifier tube particularly for service in circuits involving potentials in excess of volts and currents in excess of 10 amperes, comprising an envelope and within said envelope a gaseous filling at a pressure in excess of 0.3 millimeter of mercury, an oxide cathode, an anode having an active surface and an inactive surface, a first screening member surrounding the inactive surface of said anode, and a second screening member interposed between said cathode and the active surface of said anode, said screening members being so cooperatively arranged with respect to said cathode and said anode that electrons emitted from said cathode are prevented from directly passing to the active surface of said anode and from passing to the active surface of said anode after one reflection from any internal surface of said tube.
  • a rectifier tube particularly for service in circuits involving potentials in excess of 100 volts and currents in excess of 10 amperes, comprising an envelope and within said envelope a gaseous filling at a pressure in excess of .3 millimeter of mercury, an oxide cathode, an anode having an active surface and an inactive surface, a screening member surrounding the inactive surface of said anode, and a second screening member interposed between said cathode and the active surface of said anode, said second screening member having an aperture therein arranged to permit electrons emitted by said cathode to pass to the vicinity of the active surface of said anode and to prevent said electrons from passing directly to the active surface of said anode thereby initiating ionization of said gaseous filling in the vicinity of said anode and preventing arc-back at lower than normal cathode temperatures.

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  • Lasers (AREA)
  • Discharge Lamps And Accessories Thereof (AREA)
US731289A 1941-10-17 1947-02-27 Current converting tube Expired - Lifetime US2452861A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL233965X 1941-10-17

Publications (1)

Publication Number Publication Date
US2452861A true US2452861A (en) 1948-11-02

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Application Number Title Priority Date Filing Date
US731289A Expired - Lifetime US2452861A (en) 1941-10-17 1947-02-27 Current converting tube

Country Status (6)

Country Link
US (1) US2452861A (en:Method)
BE (1) BE447607A (en:Method)
CH (1) CH233965A (en:Method)
FR (1) FR886842A (en:Method)
GB (1) GB623012A (en:Method)
NL (1) NL61140C (en:Method)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2605438A (en) * 1948-10-30 1952-07-29 Raytheon Mfg Co Gaseous discharge device
US2605439A (en) * 1951-01-13 1952-07-29 Westinghouse Electric Corp Vapor-electric device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE458156A (en:Method) * 1945-02-08

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2605438A (en) * 1948-10-30 1952-07-29 Raytheon Mfg Co Gaseous discharge device
US2605439A (en) * 1951-01-13 1952-07-29 Westinghouse Electric Corp Vapor-electric device

Also Published As

Publication number Publication date
BE447607A (en:Method)
NL61140C (en:Method)
GB623012A (en) 1949-05-11
CH233965A (de) 1944-08-31
FR886842A (fr) 1943-10-26

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