US2450770A - High-voltage rectifying tube - Google Patents

High-voltage rectifying tube Download PDF

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Publication number
US2450770A
US2450770A US721647A US72164747A US2450770A US 2450770 A US2450770 A US 2450770A US 721647 A US721647 A US 721647A US 72164747 A US72164747 A US 72164747A US 2450770 A US2450770 A US 2450770A
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US
United States
Prior art keywords
cathode
rectifying tube
tube
voltage rectifying
anode
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
US721647A
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English (en)
Inventor
Snijders Marcus Jan
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
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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
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Publication of US2450770A publication Critical patent/US2450770A/en
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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
    • H01J17/04—Electrodes; Screens
    • H01J17/06—Cathodes

Definitions

  • This invention relates to a rectifier tube comprising a filament cathode and a metal vapour filling for use at high voltages that is to say exceeding 500 volts.
  • the cathode In the known tubes of the aforesaid type the cathode is generally coated with barium oxide or with an oxide of other alkaline earth metal in order to ensure a high emission of electrons.
  • These tubes have a limitation in that notwithstanding all kinds of screening measures, the cathode, due to the bombardment by ions, has a life of not more than some few thousands of hours. If the anode voltage exceeds some few thousands of volts, backfiring frequently occurs because the anode starts to emit at those points at which small quantities of barium which have left the cathode by volatilisation are deposited.
  • Non-carbonised tungsten-thorium cathodes have also for a long time been known, used with rare gases as well as with a metal vapour-filling, butthe life of such cathodes is short.
  • a rectifying tube according to the invention is provided with a carbonised tungsten-thorium cathode, the tube being filled with metal vapour.
  • tubes according to the invention have a long life and that there is no probability at all of backfiring due to the presence of active cathode material on the anode. Due to the cathode being surrounded with screens, the required filament current energy does not exceed twice the energy required for a cathode activated with alkaline earth metal oxides.
  • I designates the glass wall of a tube comprising an anode 2, an intermediate electrode 3 and a cathode sleeve 4.
  • the cathode sleeve contains a helical cathode 5.
  • This cathode is made of tungsten having added to it 2% of thoria.
  • This filament wire is carbonised by heating in acetylene at a pressure of about 1 mm. for a time such that about 30% of the cross sectional area of the wire is carbonised.
  • the tube is intended for use at a voltage, to be rectified, of 5 kilovolts; it has a life of many thousands of hours.
  • a drop of mercury 6 at the bottom of the tube ensures the presence of a sufiicient quantity of mercuryvapour.
  • a high-voltage rectifying tube comprising a sealed envelope containin an anode, and a cathode which is constituted by a carbonised tungsten-thorium wire and an atmosphere of a metal vapor.
  • a high-voltage rectifying tube comprising a sealed envelope containing an atmosphere of mercury vapour, and a cathode of tungsten-thorium wire carbonized to an extent within about 30% of its cross-sectional area.
  • a high-voltage, rectifying tube comprising a sealed envelope containing an atmosphere of mercury vapour, an anode, a cathode of tungstenthorium wire carbonized to an extent within about 30% of its cross-sectional area, and a semienclosure for the cathode within the direct path between the cathode and the anode.

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  • Physical Or Chemical Processes And Apparatus (AREA)
US721647A 1945-11-14 1947-01-11 High-voltage rectifying tube Expired - Lifetime US2450770A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL2450770X 1945-11-14

Publications (1)

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US2450770A true US2450770A (en) 1948-10-05

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ID=19874252

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US721647A Expired - Lifetime US2450770A (en) 1945-11-14 1947-01-11 High-voltage rectifying tube

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US (1) US2450770A (fr)
FR (1) FR935845A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2693546A (en) * 1948-07-10 1954-11-02 Eitel Mccullough Inc Electron emitter for electron tubes
US2879432A (en) * 1956-03-16 1959-03-24 Gen Electric Electron emitter

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2088249A (en) * 1931-08-04 1937-07-27 Raytheon Mfg Co Gaseous rectifier

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2088249A (en) * 1931-08-04 1937-07-27 Raytheon Mfg Co Gaseous rectifier

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2693546A (en) * 1948-07-10 1954-11-02 Eitel Mccullough Inc Electron emitter for electron tubes
US2879432A (en) * 1956-03-16 1959-03-24 Gen Electric Electron emitter

Also Published As

Publication number Publication date
FR935845A (fr) 1948-07-01

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