US3646380A - Rotating-anode x-ray tube with a metal envelope and a frustoconical anode - Google Patents

Rotating-anode x-ray tube with a metal envelope and a frustoconical anode Download PDF

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Publication number
US3646380A
US3646380A US851169A US3646380DA US3646380A US 3646380 A US3646380 A US 3646380A US 851169 A US851169 A US 851169A US 3646380D A US3646380D A US 3646380DA US 3646380 A US3646380 A US 3646380A
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United States
Prior art keywords
anode
envelope
disc
ray tube
support
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Expired - Lifetime
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US851169A
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English (en)
Inventor
Walter Hartl
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US Philips Corp
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US Philips Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/24—Tubes wherein the point of impact of the cathode ray on the anode or anticathode is movable relative to the surface thereof
    • H01J35/26—Tubes wherein the point of impact of the cathode ray on the anode or anticathode is movable relative to the surface thereof by rotation of the anode or anticathode
    • 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
    • H01J35/08—Anodes; Anti cathodes
    • H01J35/10—Rotary anodes; Arrangements for rotating anodes; Cooling rotary anodes

Definitions

  • An y tube having an evacuated mew] envelope i an anode is mounted for rotation about an axis perpendicular [52] US. Cl. ..3l3/60, 313/35, 3113/34;; to an electron beam produced by a cathode.
  • the anode is H in CI il, cooled and is frustoconical in shape, the inclined surface of which intercepts the electron beam
  • the anode is in the form of a disc consisting of molybdenum or graphite surrounded by a tire of tungsten or an alloy of tungsten and is at ground potential while the cathode is at a
  • Reierences cued potential which causes X-rays to be generated and is secured UNITED STATES PATENTS to the envelope by an insulator having a recess for receiving a plug connected to a source of potential sufficient to generate 2,427,203 9/1947 Essig ..313/60 X x 2,480,198 8/1949 Rogers 313/55 X 2,549,614 4/1951 Leighton ..313/60 X 4 Claims, 1 Drawing Figure PAIENTEBFEB 29 1912 1N VENTOR.
  • the invention relates to a rotating-anode X-ray tube having a high-load capacity.
  • a plane disc is arranged for rotation about a shaft which extends substantially parallel to the direction of the electron beam.
  • On one surface of the disc there is traced at least one focal-spot path the radius of which is limited to at most 80 percent of the radius of the disc, because it must be spaced from the edge of the disc for safety reasons.
  • the respective part of the disc is heated to a particularly high temperature; the thermal expansion causes pressure to be exerted on the areas lying outside the focal-spot path and a tensile force to be exerted on the areas of the disc lying within said path.
  • this construction has the disadvantage that the electron beam impinges laterally on the curved surface of the anode cylinder, i.e., at an angle of about 45 to the normal to this surface.
  • the position of the focal spot depends among other things on the value of the applied voltage.
  • the focal spot is shifted when the anode is not exactly circular in cross section, as may be the case even in accurately balanced anodes. Hence, these constructions have acquired no importance in practice so far.
  • the shaft about which the anode rotates is joumaled so as to extend at right angles to the direction of the electron beam
  • the above-described disadvantages are avoided in that the anode disc is shaped in the form of a frustum of a cone.
  • the electron beam impinges in the direction of the normal to the axis of rotation and the X-rays produced are emitted substantially parallel to the axis of rotation.
  • the drawing shows an X-ray tube having an grounded cylindrical metal envelope 1. Because a metal envelope is used instead of the usual glass envelope this tube need not be arranged in a protective casing, which generally is filled with oil. The lead coating necessary for reasons of protection against radiation can be directly applied to the metal envelope 1.
  • the cathode 2, to which a high voltage is applied, is secured to one end of a ceramic insulator 3, the other end of which is joined to the front face of the metal envelope in a vacuumtight manner.
  • a conical highvoltage plug is entirely inserted in a matching recess in the ceramic insulator.
  • a disc anode 4 which is mounted on a shaft 6 which extends at right angles to the direction of the electron beam and is journaled in bearings 7 arranged in a copper block which is adapted to be cooled.
  • the rotating anode disc is shaped in the form of a frustum of a cone the curved surface of which is inclined at an angle of about 17 to 20 to the shaft and is surrounded along its edge by a tire 9 made of tungsten or tungsten-molybdenum or by a tape of a rhenium-tungsten-molybdenum ply material.
  • the diameter of the path of the focal spot is substantially equally to the diameter of the disc, which in itself enables the short-time loading to exceed that obtainable in the conventional tubes in which the rotation shaft extends parallel to the electron path and in which the diameter of the path of the focal spot must be smaller than the disc diameter by about 20 percent.
  • a centrally apertured metal screen 16 which electrostatically screens the entire lower tube portion with the exception of the part of the focal-spot path on which the electron beam impinges from the cathode.
  • the rotating anode can be arranged so relatively to the cathode that the electrons impinge on the tire 9 in the direction of the normal to this axis.
  • Small deviations of the disc diameter from an exactly circular form have only a slight influence on the position of the focal spot; the value of the voltage set up between the anode and the cathode has no influence at all on this position. Consequently, the X-ray window 17 in the form of a beryllium plate can be arranged close to the focal spot. This enables diaphragms to be arranged at a distance of not more than 1 to 2 cm from the focal spot, so that the stray radiation emitted from metal components outside the focal spot is reduced to a minimum.
  • the rotating anode may be made of the usual material, i.e., molybdenum. However, because its mechanical strength is greatly increased by the tire 9 and because its temperature and voltage distribution is rotation symmetrical and symmetrical about the axis, it may alternatively be made of a material of lower mechanical strength but better thermal properties, such as graphite or glass carbon. For example, at the same temperature a graphite body radiates more heat than the molybdenum body as used for the conventional rotating anodes. In addition, graphite has a higher thermal load capacity than molybdenum so that the amount of heat radiated by the anode, which amount, as is known, increases as the fourth power of the temperature, is considerably greater.
  • Components 10 provided for securing the anode 4 and the shaft 6 are proportioned so that their thermal resistivity is sufficient to limit the amount of heat transferred by the hot anode disc to the bearings 7 so that the temperature of the bearings does not exceed 300 to 400 C.
  • a cavity 11 provided in the copper block 8 prevents heat radiated by the anode disc to the inner surface of the block from reaching the bearings in the outer part of the block by the shortest possible path.
  • a disc 12 of blackened copper is arranged which is secured to the shaft 6 and radiates part of the heat absorbed so that the ratio between the energy radiated and the energy transferred to the bearings is further increased.
  • the cooling coils for water which extend close to the bearings contribute to prevent impermissible heating of the bearings.
  • the X-shaft is joumaled at both ends, the unbalance forces and the loads imposed on the bearings can be maintained small. Hence the mass of the rotating anode and/or its speed may be increased, and this involves a further increase of the thermal load capacity.
  • the rotating anode is driven by means of a disc-shaped rotor which is secured to the end of the shaft 6 remote from the window and forms part of an induction motor of a commutatorless direct-current motor arranged outside the tube envelope (not shown).
  • a ceramic disc 14 is arranged in a vacon ring 15 welded to the casing.
  • the airgap which in this case is defined by the ceramic disc and the evacuated space between the rotor t3 and the ceramic disc 14, in this embodiment may be considerably smaller than in a rotating-anode tube having an anode at which a high voltage is set up, so that with the same driving power a shorter starting time of the rotating anode or with the same starting time a smaller driving power is possible.
  • the anode disc can readily be balanced by means of bores in its plane faces, and this does not impair its high-voltage properties owing to the provision of the metal screen 16.
  • the copper block 8 is preferably joined to the metal envelope by argon arc welding after the anode and the shaft have been placed in position.
  • the short-time load can be about doubled and a continuous load of about 6 kilowatts (as compared with 500 watts in the usual rotating anode tubes) is permissible.
  • the tube is suitable not only for medical diagnostics but also for structure investigations.
  • An X-ray tube comprising a substantially cylindrical metal envelope, an electron-emitting element within the envelope for producing an electron beam in the axial direction of the envelope, a disc-shaped anode having a frustoconical circumferential surface positioned to intercept electrons, means to rotatably support the anode at right angles to the axis of the envelope including a shaft, a heat conducting metal support hermetically secured to the metal envelope, and bearing means positioned within said support for supporting said shaft.
  • An X-ray tube as claimed in claim I in which the support consists of copper and has channels for a circulating cooling fluid.
  • An X-ray tube as claimed in claim 1 in which the support has a cavity on each side opposite the anode between the anode and the bearing means in which rotatable blackened copper discs are secured to the shaft.
  • An X-ray tube as claimed in claim 1 in which the conductive support has a portion spaced from the wall of the envelope and a disc-shaped rotor member of an externally positioned induction motor rotatably supported by said shaft is positioned in the space between the conductive support and the inner wall of the envelope, and an insulating disc is provided in the wall of said envelope opposite said disc shaped rotor member.

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  • X-Ray Techniques (AREA)
US851169A 1968-08-17 1969-08-19 Rotating-anode x-ray tube with a metal envelope and a frustoconical anode Expired - Lifetime US3646380A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE1764846 1968-08-17

Publications (1)

Publication Number Publication Date
US3646380A true US3646380A (en) 1972-02-29

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ID=5698160

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Application Number Title Priority Date Filing Date
US851169A Expired - Lifetime US3646380A (en) 1968-08-17 1969-08-19 Rotating-anode x-ray tube with a metal envelope and a frustoconical anode

Country Status (6)

Country Link
US (1) US3646380A (de)
AT (1) AT297865B (de)
BE (1) BE737628A (de)
FR (1) FR2016140B1 (de)
GB (1) GB1232160A (de)
NL (1) NL6912349A (de)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3753020A (en) * 1971-11-26 1973-08-14 Philips Electronics And Pharm Multi-anode x-ray tube
US3758801A (en) * 1972-05-22 1973-09-11 Machlett Lab Inc Cylindrical target x-ray tube
DE2448497A1 (de) * 1974-10-11 1976-04-22 Licentia Gmbh Roentgenroehre und vorrichtung mit einer roentgenroehre
US3969131A (en) * 1972-07-24 1976-07-13 Westinghouse Electric Corporation Coated graphite members and process for producing the same
US4035685A (en) * 1974-04-11 1977-07-12 U.S. Philips Corporation Solid cathode cap for an X-ray tube
US4413356A (en) * 1978-10-16 1983-11-01 U.S. Philips Corporation Flat rotary-anode X-ray tube
US4644217A (en) * 1984-05-09 1987-02-17 Thomson-Csf Electron tube with a device for cooling the grid base
EP0425718A1 (de) * 1989-10-30 1991-05-08 Siemens Aktiengesellschaft Röntgenstrahlerzeuger
US5052034A (en) * 1989-10-30 1991-09-24 Siemens Aktiengesellschaft X-ray generator
US5173931A (en) * 1991-11-04 1992-12-22 Norman Pond High-intensity x-ray source with variable cooling
EP1524737A1 (de) * 2003-10-17 2005-04-20 Rigaku Corporation Stromdrehkollektor und Drehanoden-Röntgenröhre
US20100290595A1 (en) * 2009-05-18 2010-11-18 King Fahd University Of Petroleum And Minerals X-ray tube having a rotating and linearly translating anode
US20100290594A1 (en) * 2009-05-18 2010-11-18 Jihad Hassan Al-Sadah X-ray tube having a rotating and linearly translating anode
WO2022223965A1 (en) * 2021-04-23 2022-10-27 Oxford Instruments X-ray Technology Inc. X-ray tube anode
CN117524816A (zh) * 2024-01-04 2024-02-06 科罗诺司医疗器械(上海)有限公司 X射线管及阳极回收方法

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2610660C3 (de) * 1976-03-13 1979-02-22 Philips Patentverwaltung Gmbh, 2000 Hamburg Drehanoden-Röntgenröhre
EP0009946A1 (de) * 1978-10-02 1980-04-16 Pfizer Inc. Röntgenröhre
ATE14953T1 (de) * 1981-04-21 1985-08-15 Robert S Ledley Mikrofokus-roentgenroehre.

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2427203A (en) * 1945-05-14 1947-09-09 Farnsworth Television & Radio Bearing for vacuum tube work
GB602750A (en) * 1945-07-16 1948-06-02 Eric John Ward Watkinson Improvements in or relating to x-ray tubes
GB616490A (en) * 1942-11-25 1949-01-21 Philips Nv Improvements in disc anodes for x-ray tubes
US2480198A (en) * 1945-11-26 1949-08-30 Machlett Lab Inc Electrical discharge tube
GB646274A (en) * 1948-10-08 1950-11-15 Norman Charles Cordingly Improvements relating to x-ray tubes
US2549614A (en) * 1948-10-27 1951-04-17 Westinghouse Electric Corp Rotary anode x-ray tube
US2594564A (en) * 1948-12-16 1952-04-29 Kehrli Hans Revolving anode roentgen ray tube

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB616490A (en) * 1942-11-25 1949-01-21 Philips Nv Improvements in disc anodes for x-ray tubes
US2427203A (en) * 1945-05-14 1947-09-09 Farnsworth Television & Radio Bearing for vacuum tube work
GB602750A (en) * 1945-07-16 1948-06-02 Eric John Ward Watkinson Improvements in or relating to x-ray tubes
US2480198A (en) * 1945-11-26 1949-08-30 Machlett Lab Inc Electrical discharge tube
GB646274A (en) * 1948-10-08 1950-11-15 Norman Charles Cordingly Improvements relating to x-ray tubes
US2549614A (en) * 1948-10-27 1951-04-17 Westinghouse Electric Corp Rotary anode x-ray tube
US2594564A (en) * 1948-12-16 1952-04-29 Kehrli Hans Revolving anode roentgen ray tube

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3753020A (en) * 1971-11-26 1973-08-14 Philips Electronics And Pharm Multi-anode x-ray tube
US3758801A (en) * 1972-05-22 1973-09-11 Machlett Lab Inc Cylindrical target x-ray tube
US3969131A (en) * 1972-07-24 1976-07-13 Westinghouse Electric Corporation Coated graphite members and process for producing the same
US4035685A (en) * 1974-04-11 1977-07-12 U.S. Philips Corporation Solid cathode cap for an X-ray tube
DE2448497A1 (de) * 1974-10-11 1976-04-22 Licentia Gmbh Roentgenroehre und vorrichtung mit einer roentgenroehre
US4413356A (en) * 1978-10-16 1983-11-01 U.S. Philips Corporation Flat rotary-anode X-ray tube
US4644217A (en) * 1984-05-09 1987-02-17 Thomson-Csf Electron tube with a device for cooling the grid base
EP0425718A1 (de) * 1989-10-30 1991-05-08 Siemens Aktiengesellschaft Röntgenstrahlerzeuger
US5052034A (en) * 1989-10-30 1991-09-24 Siemens Aktiengesellschaft X-ray generator
US5295175A (en) * 1991-11-04 1994-03-15 Norman Pond Method and apparatus for generating high intensity radiation
US5173931A (en) * 1991-11-04 1992-12-22 Norman Pond High-intensity x-ray source with variable cooling
EP1524737A1 (de) * 2003-10-17 2005-04-20 Rigaku Corporation Stromdrehkollektor und Drehanoden-Röntgenröhre
US20050082936A1 (en) * 2003-10-17 2005-04-21 Rigaku Corporation Rotary current-collecting device and rotating anode X-ray tube
US7005774B2 (en) 2003-10-17 2006-02-28 Rigaku Corporation Rotary current-collecting device and rotating anode X-ray tube
US20060051980A1 (en) * 2003-10-17 2006-03-09 Rigaku Corporation Rotary current-collecting device and rotating anode X-ray tube
US20100290595A1 (en) * 2009-05-18 2010-11-18 King Fahd University Of Petroleum And Minerals X-ray tube having a rotating and linearly translating anode
US20100290594A1 (en) * 2009-05-18 2010-11-18 Jihad Hassan Al-Sadah X-ray tube having a rotating and linearly translating anode
US7852987B2 (en) 2009-05-18 2010-12-14 King Fahd University Of Petroleum And Minerals X-ray tube having a rotating and linearly translating anode
US8259905B2 (en) 2009-05-18 2012-09-04 King Fahd University Of Petroleum And Minerals X-ray tube having a rotating and linearly translating anode
WO2022223965A1 (en) * 2021-04-23 2022-10-27 Oxford Instruments X-ray Technology Inc. X-ray tube anode
CN117524816A (zh) * 2024-01-04 2024-02-06 科罗诺司医疗器械(上海)有限公司 X射线管及阳极回收方法
CN117524816B (zh) * 2024-01-04 2024-03-22 科罗诺司医疗器械(上海)有限公司 X射线管及阳极回收方法

Also Published As

Publication number Publication date
AT297865B (de) 1972-04-10
FR2016140A1 (de) 1970-05-08
NL6912349A (de) 1970-02-19
FR2016140B1 (de) 1975-11-07
BE737628A (de) 1970-02-18
GB1232160A (de) 1971-05-19

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