US3851204A - Rotatable anode for x-ray tubes - Google Patents

Rotatable anode for x-ray tubes Download PDF

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Publication number
US3851204A
US3851204A US00337311A US33731173A US3851204A US 3851204 A US3851204 A US 3851204A US 00337311 A US00337311 A US 00337311A US 33731173 A US33731173 A US 33731173A US 3851204 A US3851204 A US 3851204A
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US
United States
Prior art keywords
anode
disc
rotatable
tube
ray
Prior art date
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Expired - Lifetime
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US00337311A
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English (en)
Inventor
F Rollfinke
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General Electric Co
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General Electric Co
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Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Priority to US00337311A priority Critical patent/US3851204A/en
Priority to NLAANVRAGE7401850,A priority patent/NL176621C/xx
Priority to AT156074A priority patent/AT340008B/de
Priority to FR7406908A priority patent/FR2220094B1/fr
Priority to DE2409526A priority patent/DE2409526C2/de
Application granted granted Critical
Publication of US3851204A publication Critical patent/US3851204A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H01J35/08—Anodes; Anti cathodes
    • H01J35/10—Rotary anodes; Arrangements for rotating anodes; Cooling rotary anodes

Definitions

  • anode of the rotatable type adapted for use in an X-ray generating tube, wherein the anode is of circular disc-like configuration having an annular focus area on each of its sides adjacent the periphery, these focus areas being inclined symmetrically to the central plane of the disc whereby the disc may be turned side-for-side in a single beam X-ray tube to expose a fresh target surface after one surface has been pitted or burned, or may be used in an X-ray tube hav ing provision for dual beams in which case the target areas of the anode may be employed simultaneously to produce a reinforced beam or, alternatively, singly in sequence to reduce the frequency of disassembling the tube to effect replacement of the anode.
  • This invention relates to anodes for Xray generating tubes and is particularly concerned with a type of anode adapted to be rotated within the X-raytube.
  • the invention is characterized by an anode configuration designed to provide improvements in physical and mechanical properties and operating capabilities of the anode, and hence of the X-ray tube, in comparison to anodes heretofore used.
  • the invention is directed more particularly to solid single metal as well as bimetal or composite metalnonmetal rotated anodes in which an anode disc, or at least a portion of it, is composed of different materials in order to take advantage of different properties of those materials. Difficulty has been experienced with the use of prior bimetal rotatable disc anodes owing to distortion occasioned by difference in thermal expansion between the metals, with resulting distortionin the X-ray beam. It is accordingly a purpose of the present invention to obviate this difficulty and to achieve an improved structure from forging asymmetrical shape.
  • the anode is in the form of a circular plate or disc of shallow concavo-convex shape.
  • the anode disc is mounted on a rotating shaft supported within the glass envelope of the tube with the convex surface of the disc facing a cathode supported in spaced relation thereto.
  • the peripheral margin of the convex surface of the disc opposing the cathode constitutes the target or focus area and is bombarded by electrons given off by the cathode when the tube in in operation.
  • This focus area is tilted to the path of electrons impinging upon it so that X-ray emanations produced by the bombardment will be directed or beamed laterally (radially from the disc) to intercept the subject which is to be examined.
  • the convexity of the disc thus effectively provides the target tilting mentioned above with a minimum amount of material in the disc.
  • This minimal material feature is desirable both from an economic standpoint, as the better target metals are quite expensive, as well as for functional reasons.
  • the other type of rotated anode previously used is generally cylindrical with a conical or frusto-conical closed end which serves as the focus area. In both prior types of anodes it is possible to use only one surface as the focus area, and when this surface becomes exhausted or unuseable due to erosion, coarsening, distortion, etc., the tube must be disassembled and the anode replaced or reconditioned.
  • the disc may be removed from the rotating shaft and turned side-for-side and replaced on the shaft to bring the other target surface into position for use.
  • the operating life of the anode is thereby effectively doubled before it must be replaced or reconditioned. If two cathodes are assembled in an X-ray tube, double life can be achieved by using the second cathode with the second focus path without having to remove and reassemble the target.
  • FIG. 1 is an elevational view, partly in:section,'. of a; typical X-ray generating tube incorporating a rotatable anode of the present invention
  • FIG. 2 is a plan view on an enlarged'scalelooking at the face of the rotatable anode shown in. FIG. 1;
  • FIG. 3 is an edge or side view of the anodeseen'in FIG. 2;
  • FIG. 4 is a cross sectional view of the anode taken on line 44 of FIG. 2.
  • the X-ray tube 10 seen in FIG. 1 consistsbasically of a glass or other envelope 12 containing a cathode unit 14 which is heated by a suitable filament 16 to cause the emission of electrons. There is also disposed: within envelope 12 an anode unit ls comprisinga rotor and bearing support for ashaft 20 andaa circular anode disc 22 mounted on the end of the shaft. The peripheral. 7
  • Anode unit 18 incorporates suitable inductive or magnetic means (not shown) by which to effect rotation of shaft 20 upon' applicationof a suitable rotating electromagnetic field externally encircling, the neck portion of the tube.
  • the tube is supplied with relatively low voltage filament current at terminals 24, one of which also may serve as the cathode terminal.
  • the rotatable anode disc is connected to terminal 26 for application thereto of high voltage potential.
  • anode disc 22 is driven by unit 18 at high r.p.m., and a high rectified voltage is applied between cathode 14 and the anode 22 through the aforesaid terminals 24, 26, to cause electrons emitted'by the cathode to be attracted to and impinge upon the surface of rotating disc anode 22. Impingement of the electrons upon the face of the disc produces the X-ray I emanations which are projected laterally through the side wall of envelope 12 of the tube 10 and focused on the subject to be examined. Most of the energy of the accelerated electrons striking the rotating anode disc 22 is converted to heat, with the result that the anode disc soon reaches a very high temperature.
  • bimetallic rotatable anode discs are frequently used, wherein the focus area of the rotating anode disc is formed of one of the extremely high-melting refractory metals or alloys able to withstand great temperatures, while the balance and generally the major portion of the rotating disc anode is formed of a lower cost but still relatively high melting materials such as molybdenum or graphite which has better thermal properties.
  • anode disc 22 comprises a relatively thin substantially flat circular disc having an axial aperture 30 by which the disc is adapted to be mounted on the end of shaft 20.
  • Disc 22 is of uniform configuration on each of its opposite faces whereby the central plane normal to the aperture 30 constitutes a plane of symmetry, as indicated by the dashed line marked S in FIG. 4.
  • the peripheral margins of disc 22 are beveled, forming annular, substantially planar faces 32 which are equally inclined to the plane of symmetry. These faces constitute the target or focus areas of the anode, and increments of these faces are progressively exposed to electron ,bombardment from the cathode during rotation of the disc.
  • the target faces 32 are disposed at a base angle which varies from around 5 to measured between the projection of an element or generatrix of revolution of the face and the aforesaid plane of symmetry S.
  • the target surfaces 32 at each side of disc 22 are formed of thin layers or laminations of a highly refractory metal such as tungsten or tungsten-rhenium alloy, while the central major portion of the disc is formed of a high melting material such as molybdenum, molybdenum alloys, or graphite. It is of course possible to use an all tungsten, an all rhenium, or an all refractory metal alloy disc, and fabrication of the disc by forging any of these metals or alloys affords a particularly desirable anode structure.
  • a highly refractory metal such as tungsten or tungsten-rhenium alloy
  • a high melting material such as molybdenum, molybdenum alloys, or graphite.
  • Rotatable anode discs are generally 3 to 6 inches in diameter and from about Va to of an inch thick. These dimensions are dictated to a large degree by practical considerations involving the balancing of heat capacity with heat dissipating capabilities, compactness and maneuverability of the X-ray apparatus. Other dimensions may be used.
  • the anode unit when one of the target surfaces 32 becomes exhausted, the anode unit may be removed from the tube to allow disc 22 to be taken off of shaft 22 and turned side-for-side so as to bring the opposite target surface 32 opposite cathode 14 when the members are reassembled in the tube.
  • a rotated anode disc of this configuration it is possible to provide a second cathode in the X-ray located adjacent the opposite target face, whereby both the target faces may be used simultaneously to produce a reinforced X-ray beam, or individually to produce a separate beam.
  • anode disc Other symmetrical configurations of the anode disc are possible in place of the mutually inclined planar faces 32.
  • such faces may be stepped, curvo-conical or the inclination may be reversed so that they are mutually inclined away from each other in the radial outward direction, depending of course on the design of the X-ray tube in which such rotated anodes are employed, or may have different inclinations.
  • a rotatable anode for an X-ray tube comprising:
  • said disc having oppositely disposed continuous annular faces adjacent its periphery;
  • said annular faces being mutually and symmetrically inclined toward a plane through and disc perpedicular to said axis.
  • a rotatable anode as defined in claim 1' wherein said annular faces are mutually inclined towards each other in the radial outward direction.
  • said disc is forged of said metals and alloys.

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  • X-Ray Techniques (AREA)
US00337311A 1973-03-02 1973-03-02 Rotatable anode for x-ray tubes Expired - Lifetime US3851204A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US00337311A US3851204A (en) 1973-03-02 1973-03-02 Rotatable anode for x-ray tubes
NLAANVRAGE7401850,A NL176621C (nl) 1973-03-02 1974-02-11 Roteerbare anode voor roentgenbuis.
AT156074A AT340008B (de) 1973-03-02 1974-02-26 Rotierbare anode fur rontgenrohren
FR7406908A FR2220094B1 (enrdf_load_html_response) 1973-03-02 1974-02-28
DE2409526A DE2409526C2 (de) 1973-03-02 1974-02-28 Drehanodenscheibe für eine Röntgenröhre

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00337311A US3851204A (en) 1973-03-02 1973-03-02 Rotatable anode for x-ray tubes

Publications (1)

Publication Number Publication Date
US3851204A true US3851204A (en) 1974-11-26

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00337311A Expired - Lifetime US3851204A (en) 1973-03-02 1973-03-02 Rotatable anode for x-ray tubes

Country Status (5)

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US (1) US3851204A (enrdf_load_html_response)
AT (1) AT340008B (enrdf_load_html_response)
DE (1) DE2409526C2 (enrdf_load_html_response)
FR (1) FR2220094B1 (enrdf_load_html_response)
NL (1) NL176621C (enrdf_load_html_response)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4005322A (en) * 1976-03-08 1977-01-25 The Machlett Laboratories, Incorporated Rotating anode target structure
US4052640A (en) * 1976-06-21 1977-10-04 General Electric Company Anodes for rotary anode x-ray tubes
US4327305A (en) * 1978-11-20 1982-04-27 The Machlett Laboratories, Inc. Rotatable X-ray target having off-focal track coating
GB2212975A (en) * 1987-11-30 1989-08-02 Rigaku Denki Kabushiki Kaisha Rotating anode X-ray tube
US5689543A (en) * 1996-12-18 1997-11-18 General Electric Company Method for balancing rotatable anodes for X-ray tubes
US6233349B1 (en) 1997-06-20 2001-05-15 General Electric Company Apparata and methods of analyzing the focal spots of X-ray tubes
US20050163285A1 (en) * 2003-12-10 2005-07-28 Kabushiki Kaisha Toshiba X-ray CT apparatus

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0030453A1 (en) * 1979-12-05 1981-06-17 Pfizer Inc. Rotating anode-type X-ray tube and method of generating an X-ray beam
AT14990U1 (de) * 2015-05-08 2016-10-15 Plansee Se Beidseitig verwendbare Drehanode

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2274865A (en) * 1940-02-03 1942-03-03 Machlett Lab Inc X-ray tube
US2336271A (en) * 1941-12-23 1943-12-07 Machlett Lab Inc Rotary anode x-ray tube
US2350642A (en) * 1939-10-14 1944-06-06 Schwarzer Kurt Roentgen tube with anode turning about its longitudinal axis
US2597498A (en) * 1948-12-10 1952-05-20 Joseph V Kerkhoff X-ray tube
US2900542A (en) * 1954-09-22 1959-08-18 Harry B Mceuen X-ray apparatus
US2942126A (en) * 1957-10-12 1960-06-21 Siemens Reiniger Werke Ag Rotating anode X-ray tube
US3113233A (en) * 1961-06-09 1963-12-03 Dunlee Corp X-ray tube with reverse position focal spot
US3610984A (en) * 1967-12-28 1971-10-05 Tokyo Shibaura Electric Co Rotating-anode x-ray tube with multiple focal areas
US3683223A (en) * 1968-12-16 1972-08-08 Siemens Ag X-ray tube having a ray transmission rotary anode

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT300971B (de) * 1970-03-25 1972-08-10 Metallwerk Plansee Ag & Co Kom Drehanoden-Verbundteller für Röntgenröhren

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2350642A (en) * 1939-10-14 1944-06-06 Schwarzer Kurt Roentgen tube with anode turning about its longitudinal axis
US2274865A (en) * 1940-02-03 1942-03-03 Machlett Lab Inc X-ray tube
US2336271A (en) * 1941-12-23 1943-12-07 Machlett Lab Inc Rotary anode x-ray tube
US2597498A (en) * 1948-12-10 1952-05-20 Joseph V Kerkhoff X-ray tube
US2900542A (en) * 1954-09-22 1959-08-18 Harry B Mceuen X-ray apparatus
US2942126A (en) * 1957-10-12 1960-06-21 Siemens Reiniger Werke Ag Rotating anode X-ray tube
US3113233A (en) * 1961-06-09 1963-12-03 Dunlee Corp X-ray tube with reverse position focal spot
US3610984A (en) * 1967-12-28 1971-10-05 Tokyo Shibaura Electric Co Rotating-anode x-ray tube with multiple focal areas
US3683223A (en) * 1968-12-16 1972-08-08 Siemens Ag X-ray tube having a ray transmission rotary anode

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4005322A (en) * 1976-03-08 1977-01-25 The Machlett Laboratories, Incorporated Rotating anode target structure
US4052640A (en) * 1976-06-21 1977-10-04 General Electric Company Anodes for rotary anode x-ray tubes
DE2727404A1 (de) * 1976-06-21 1977-12-29 Gen Electric Anoden fuer drehanoden-roentgenroehren
US4327305A (en) * 1978-11-20 1982-04-27 The Machlett Laboratories, Inc. Rotatable X-ray target having off-focal track coating
GB2212975A (en) * 1987-11-30 1989-08-02 Rigaku Denki Kabushiki Kaisha Rotating anode X-ray tube
FR2627900A1 (fr) * 1987-11-30 1989-09-01 Rigaku Denki Co Ltd Tube a rayons x a anode tournante
US5689543A (en) * 1996-12-18 1997-11-18 General Electric Company Method for balancing rotatable anodes for X-ray tubes
US6233349B1 (en) 1997-06-20 2001-05-15 General Electric Company Apparata and methods of analyzing the focal spots of X-ray tubes
US20050163285A1 (en) * 2003-12-10 2005-07-28 Kabushiki Kaisha Toshiba X-ray CT apparatus
US7184514B2 (en) * 2003-12-10 2007-02-27 Kabushiki Kaisha Toshiba X-ray CT apparatus

Also Published As

Publication number Publication date
DE2409526A1 (de) 1974-09-12
ATA156074A (de) 1977-03-15
NL176621B (nl) 1984-12-03
NL7401850A (enrdf_load_html_response) 1974-09-04
DE2409526C2 (de) 1984-10-04
AT340008B (de) 1977-11-25
FR2220094B1 (enrdf_load_html_response) 1979-05-25
NL176621C (nl) 1985-05-01
FR2220094A1 (enrdf_load_html_response) 1974-09-27

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