US3564317A - Cathode for an x-ray tube cooled by heat-conductive coaxial cylinders - Google Patents

Cathode for an x-ray tube cooled by heat-conductive coaxial cylinders Download PDF

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Publication number
US3564317A
US3564317A US727252A US3564317DA US3564317A US 3564317 A US3564317 A US 3564317A US 727252 A US727252 A US 727252A US 3564317D A US3564317D A US 3564317DA US 3564317 A US3564317 A US 3564317A
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United States
Prior art keywords
cathode
ray tube
glass
joined
metal
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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
US727252A
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English (en)
Inventor
Werner Berends
Walter Hartl
Heinz Jurgen Jacob
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US Philips Corp
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US Philips Corp
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Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
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Publication of US3564317A publication Critical patent/US3564317A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/04—Electrodes ; Mutual position thereof; Constructional adaptations therefor
    • H01J35/06—Cathodes
    • H01J35/066—Details of electron optical components, e.g. cathode cups

Definitions

  • the cathode constructions commonly used include a so called pinch, a hollow cylindrical glass tube being pinched at one end about a number of lead-through wires which serve to supply current to the filament or filaments.
  • a metal sleeve provided with a so-called cathode cap is slipped onto'the pinch.
  • the glass tubing can readily be joined to the glass envelop of the tube by sealing.
  • the cathode part and the glass envelope of the tube are each gripped in one of two chucks of a sealing in machine which run in synchronism, the chuck for the cathode part being wound with asbestos wool to avoid injury to the glass tubing.
  • the ends of the glass envelope and of the cathode parts are heated along their entire peripheries, bent into engagement with each other and sealed together.
  • part of the heat required for the sealing is transferred to the cathode sleeve arranged in close proximity to'the sealing zone, so that in spite of the use of a protective gas the sleeve is often oxidized.
  • the heat generated may liberate the oxygen thus bound to the surface of the metal with consequent disturbances.
  • a further disadvantage of the known construction is the insufficient transfer of heat from the interior of the tube to its surroundings with the result that during operation the cathode part is heated to temperatures at which the residual gases always present in the interior of the cathode sleeve and of the cathode cap are liberated, which may also give rise to disturbances in the completed tube.
  • the invention relates to a cathode provided with a metal cathode sleeve joined to a metal cathode cap.
  • the heat generated is conducted away from the cathode cap through coaxially arranged hollow me'tal cylinders, of which one is joined with good thermal conductivity to the cathode cap and the other projects beyond the glass envelope of the X-ray tube, both hollow cylinders being joined to one another and, as the case may be, to one end of a further coaxially arranged hollow metal cylinder.
  • FIG. 1 is a sectional view of a cathode in accordance with the invention.
  • FIG. 2 is a sectional view of a cathode in accordance with the invention in which heat is abstracted from the cathode by additional cooling;
  • FIG. 3 shows a cathode in accordance with the invention, which is joined to the glass tube envelope immediately below the cathode cap;
  • FIG. 4 shows a cathode in accordance with the invention having a metal exhaust tube.
  • a cathode 1 in F IG. 1 the outer surface of a cathode 1 is constituted by a cathode sleeve 2 and a cathode cap 3 joined thereto.
  • a cathode plate 3aand to this plate one end of a nickel sleeve 4 is rigidly secured.
  • the sleeve 4 is welded to a cylindrical member 5 which is made of a metal alloy the coefficient of thermal expansion of which is substantially equal to that of glass.
  • a metal alloy are known, for example, under the trade name Vacon".
  • a copper sleeve 6 is joined by soldering.
  • the lower rim of the cylinder 5 is sealed in a vacuum-tight manner to a glass envelope l3 and its upper rim is covered by a cap 12 of hard glass through which pass supply wires 9, l0, and 11 which serve to supply heating current to filaments 7 and 8.
  • the cylinder 6 is gripped, without the interposition of any material, in the chuck of the sealing-in machine so that the cathode can be accurately aligned with respect to the axis of the envelope.
  • a further advantage is that the heat generated during the sealing-in operation is conducted away to the chuck through the cylinder 6 and heating of the cathode sleeve 2 and/or cathode cap 3 is avoided.
  • the heat radiated by the filaments 7 and/or 8 to the cathode cap 3 is conducted away from the interior of the tube through the cylinders 4, S and 6. This ensures the cathode cap is'heated to a temperature considerably lower than the usual temperature of 250 C and more, even if the X-ray tube is operated in a gas atmosphere, for example, SF
  • This Figure shows part of a hood l5 surrounding a tube 17 the cathode of whichis insulated from the high voltage of the hood by means of a plug sleeve ,16.
  • the thermally conducting parts 5 and 6 of the cathode 1 are cooled by oil which is supplied through a pipe 19 and is conducted away by a pipe 18 at right angles thereto.
  • FIG. 3 relates to an X-ray tube having an grounded middle portion, the middle part of the glass envelope being replaced by a grounded cylindrical metal sleeve 24, 25.
  • the anode projects into the middle portion in the same manner as does the cathode cap 3 which, through the cathode plate 3a, is directly joined to the ring 5 of *Vacon.
  • the glass envelope is joined to the ring 5 of Vacon which is closed at its lower end by a cap 12 of hard glass, which is pressed against the ring 5 by the pressure difference between the vacuum in the interior of the tube and atmospheric pressure.
  • the glass envelope starts immediately below the cathode cap, metal surfaces face metal surfaces only, and this is conductive to preventing electrons emitted from impurities on the metal surface from striking the glass wall and consequently to preventing the tube from being damaged especially at very high volt ages.
  • FIG. 4 A further possibility of carrying the heat generated by the cathode-filament away from the interior of the tube is shown in FIG. 4.
  • a metal flange 21 is sealed to the glass tube er:- velope by means of a metal ring 22. Ceramic bushings for the current conductors are provided in the metal flange 21.
  • the metal tubing 6 of the cathode system may be screwed to the flange 21, if required, after the sealing-in operation.
  • a particularly advantageous feature is a metal exhaust tube 23 which is soldered in the flange and after exhaustion may be closed by pinching with a pair of special pincers, so that the difficult operation of a closing glass exhaust tube by drawing is dispensed with.
  • a cathode for an X-ray tube having a metal cathode cap characterized in that the heat generated is conducted away from the cathode cap (3) through coaxially arranged hollow cylinders (4,5,6) of which one (4) is joined to the cathode cap (3) with good thermal conductivity and another (6) projects made of a metal the coefficient of thermal expansion of which corresponds to thatof glass.
  • a cathode for an X-ray tube as claimed in claim 1 characterized in that the space in the hollow cylinder is connected to the space outside the tube by a length of metal tubing (23) with serves as an exhaust tube.

Landscapes

  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
  • X-Ray Techniques (AREA)
US727252A 1967-05-13 1968-05-07 Cathode for an x-ray tube cooled by heat-conductive coaxial cylinders Expired - Lifetime US3564317A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEM0073983 1967-05-13

Publications (1)

Publication Number Publication Date
US3564317A true US3564317A (en) 1971-02-16

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ID=7315385

Family Applications (1)

Application Number Title Priority Date Filing Date
US727252A Expired - Lifetime US3564317A (en) 1967-05-13 1968-05-07 Cathode for an x-ray tube cooled by heat-conductive coaxial cylinders

Country Status (9)

Country Link
US (1) US3564317A (pm)
JP (1) JPS5223234B1 (pm)
AT (1) AT284977B (pm)
BE (1) BE715097A (pm)
CH (1) CH482295A (pm)
DE (1) DE1614158A1 (pm)
FR (1) FR1572512A (pm)
GB (1) GB1222130A (pm)
NL (1) NL6806644A (pm)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0096824A1 (de) * 1982-06-16 1983-12-28 feinfocus Verwaltungs GmbH & Co. KG Feinfokus-Röntgenröhre und Verfahren zur Bildung eines Mikrofokus der Elektronenemission einer Röntgenröhren-Glühkathode
EP0168777A3 (en) * 1984-07-19 1987-08-19 Scanray A/S X-ray tube
CN110957200A (zh) * 2019-12-12 2020-04-03 陈瑞安 一种反射式x光管
CN115206755A (zh) * 2021-04-14 2022-10-18 上海超群检测科技股份有限公司 一种带自屏蔽x射线管及其制作方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR865443A (fr) * 1939-05-06 1941-05-23 Thomson Houston Comp Francaise Perfectionnements aux tubes à vide poussé
US2468942A (en) * 1943-03-15 1949-05-03 Hartford Nat Bank & Trust Co X-ray tube cooling apparatus
US2782334A (en) * 1952-03-10 1957-02-19 Raytheon Mfg Co Velocity modulated electron discharge devices
US3293476A (en) * 1963-01-04 1966-12-20 Varian Associates Electrode assembly for an electron discharge device made from a material having a low carbon content

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR865443A (fr) * 1939-05-06 1941-05-23 Thomson Houston Comp Francaise Perfectionnements aux tubes à vide poussé
US2468942A (en) * 1943-03-15 1949-05-03 Hartford Nat Bank & Trust Co X-ray tube cooling apparatus
US2782334A (en) * 1952-03-10 1957-02-19 Raytheon Mfg Co Velocity modulated electron discharge devices
US3293476A (en) * 1963-01-04 1966-12-20 Varian Associates Electrode assembly for an electron discharge device made from a material having a low carbon content

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0096824A1 (de) * 1982-06-16 1983-12-28 feinfocus Verwaltungs GmbH & Co. KG Feinfokus-Röntgenröhre und Verfahren zur Bildung eines Mikrofokus der Elektronenemission einer Röntgenröhren-Glühkathode
EP0168777A3 (en) * 1984-07-19 1987-08-19 Scanray A/S X-ray tube
CN110957200A (zh) * 2019-12-12 2020-04-03 陈瑞安 一种反射式x光管
CN115206755A (zh) * 2021-04-14 2022-10-18 上海超群检测科技股份有限公司 一种带自屏蔽x射线管及其制作方法

Also Published As

Publication number Publication date
DE1614158A1 (de) 1971-04-29
CH482295A (de) 1969-11-30
AT284977B (de) 1970-10-12
FR1572512A (pm) 1969-06-27
NL6806644A (pm) 1968-11-14
GB1222130A (en) 1971-02-10
BE715097A (pm) 1968-11-13
JPS5223234B1 (pm) 1977-06-22

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