US2311724A - X-ray tube - Google Patents

X-ray tube Download PDF

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Publication number
US2311724A
US2311724A US390321A US39032141A US2311724A US 2311724 A US2311724 A US 2311724A US 390321 A US390321 A US 390321A US 39032141 A US39032141 A US 39032141A US 2311724 A US2311724 A US 2311724A
Authority
US
United States
Prior art keywords
anode
magnetic
envelope
pedestal
ring
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
US390321A
Other languages
English (en)
Inventor
Zed J Atlee
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.)
General Electric X Ray Corp
Original Assignee
General Electric X Ray Corp
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
Priority to BE477898D priority Critical patent/BE477898A/xx
Application filed by General Electric X Ray Corp filed Critical General Electric X Ray Corp
Priority to US390321A priority patent/US2311724A/en
Priority to GB7324/42A priority patent/GB556787A/en
Application granted granted Critical
Publication of US2311724A publication Critical patent/US2311724A/en
Priority to FR940157D priority patent/FR940157A/fr
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
    • 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
    • H01J35/101—Arrangements for rotating anodes, e.g. supporting means, means for greasing, means for sealing the axle or means for shielding or protecting the driving
    • H01J35/1017—Bearings for rotating anodes
    • H01J35/1024—Rolling bearings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2235/00—X-ray tubes
    • H01J2235/10—Drive means for anode (target) substrate
    • H01J2235/1026—Means (motors) for driving the target (anode)
    • H01J2235/1033—Means (motors) for driving the target (anode) mounted within the vacuum vessel

Definitions

  • This invention relates in general to rotatable devices and has more particular reference to rotatable structures enclosed in sealed envelopes, the invention pertaining especially to an improved rotatable anode structure for use in X- ray tubes.
  • An important object of the present invention is to provide a rotating structure of the character mentioned, having magnetic driving means formed and arranged therein and operable to rotate the structure; a further object being to form the driving means as a permanent magnet built into the rotating structure and the mounting on which it is carried; a still further object being to utilize the unbalancing of a magnetic eld through thermal inversion to develop driving torque.
  • Another important object is to provide an improved magnetic drive for the rotating anode in an X-ray tube; a further important object being to provide for driving the anode of an X-ray tube by establishing a magnetic field at the anode and by unbalancing the iield by heating a portion of the anode lying in said eld above the magnetic inversion temperature of the anode material.
  • Another important object resides in providing an improved mounting structure for a rotary device of the character mentioned; a further object being to form the mounting as a hollow pedestal within which is journaled a turnable spindle carrying the rotatable device, whereby the pedestal may form a stationary mounting for carrying the magnetic driving means and other auxiliary equipment in position to co-operate with the rotary structure; a further object being to turnably support the carrying spindle inpreferably roller bearings disposed on the pedestal; and a still furtherobject being to provide means on the pedestal for lubricating the bearings therein and to control the application of lubricant from a control station outwardly of the device.
  • Figure 1 is a sectional view taken longitudinally through an X-ray generator provided with a rotating anode embodying my present invention
  • Figure 2 is a sectional view taken substantially along the line 2 2 in Figure 1;
  • Figure 3 is a graphical representation illus- Ill., assignor to General ation, Chicago, Ill., a cor- (Cl. Z-148) trating loss of magnetism with rise in temperature of iron, nickel and cobalt.
  • an X-ray generator Il comprising spaced-apart cathode and anode means I3 and l5 enclosed within a preferably glass envelope Il.
  • the anode l5 is of the rotating type, being turnably supported for rotation on mounting means I9 which, in turn, is supported on the envelope I'l at one end thereof.
  • the anode may be rotatably supported on the mounting means in any suitable fashion, and although the structure and arrangement of the anode mounting does not necessarily limit the broader aspects of the present invention, certain features of the mounting facilitate-and co-operate to advantage in conjunction with the magnetic driving means.
  • the mounting means I9 comprises a pedestal having a stem-like portion 2l extending outwardly of the envelope and a portion 29 extending within the envelope.
  • the anode l5 is rotatably mounted on the portion 29, and the pedestal is sealed to the envelope at the re-entrant portion 23, which denes an opening in which the pedestal extends.
  • the pedestal is provided with an annular shoulder 3l carrying, sealed thereon, a plate or disk 32 having a cylindrical rim 33 sealed at one end to the disk 32, the opposite end of the rim providing an annular edge forming a glass-to-metal seal 34 with the envelope at the inner end of the reentrant portion 23. This seal supports the pedestal and the anode thereon.
  • X-ray generators functionV to producevX-rays in response to the -activation of the anode by'electronic action established by the operation of-the cathode -
  • Electronic impingement onthe target results inthe generation of relatively large quantities of heat at the target, which is dissipated thence through the body of the anode l5.
  • the temperature of the anode at the Zone of electron impingernent on the target 4l may momentarily be of the order in excess of 750 centigrade.
  • X-ray generators are conditioned for operation by exhausting from the envelope substantially all gaseous and other impurities by evacuating the envelope, as by means of a molecular exhaust pump, and nally sealing the envelope in evacuated condition.
  • the anode I5 comprises a cylindrical body 39 having an open end receiving and embracing the pedestal portion 29.
  • the opposite end of the anode body is enclosed and is formed with an axial head or neck 25, which affords a mounting for the annular target member 4I.
  • the target member as shown, comprises an annular ring of suitable material, such as tungsten, which is embedded and secured in the preferably copper body of the anode at the end of the neck 25.
  • the target ring extends outwardly of the head to form an annular grove vor space 42 with the closed end of the cylindrical body 30.
  • the anode also carries a ring 44 of magnetic material, such as iron, nickel, cobalt, or alloys thereof, which is fastened securely in the anode structure and forms a part thereof, said ring 44 extending in the groove 42 immediately behind and adjacent to, and in intimate thermal contact with the target ring 4 I.
  • a ring 44 of magnetic material such as iron, nickel, cobalt, or alloys thereof
  • I provide means forming a magnetic circuit on the stationary and rotatable por- Y tions of the anode structure, said magnetic circuit comprising a magnet 81 fastened on the stationary pedestal in position to magnetically cooperate with the ring 44 on the rotatable anode I5.
  • the magnet 81 comprises a bar of permanently magnetized material characterized by the ability to retain magnetic properties at the operating temperature of the device.
  • Alnico is a suitable material for the purpose.
  • the permanent magnet 81 is anchored at one end on a mounting piece 89 which seats upon the pedestal portion 29 adjacent the seal ring 32, the parts being rigidly held together and in operating position, as by means of holding screws 9
  • the bar magnet 81 extends from its mounting along the side of the anode body 30 and is formed, at its end remote from the mounting 89, with a shoe 93 which extends in the annular groove or space 42 immediately adjacent and in magnetic 'relationship with the ring 44.
  • Theishoe 93 may, of course, be formed as an integral part of the magnet 81, or may conveniently comprise a sepa'- rately formed member of sofi; ironsecured to the bar 81, as by means of fastening screwsv 95.
  • the shoe 93 is formed and arranged to make ⁇ a small gap clearance with the ring 44. It will be noted that the shoe 93 faces that portion of the ring 44 which underlies the focal spot or zone of electron impact upon the target ring 4I. When the generator is in operation, electron impact on the target 4I raises the temperature of thev ring 4I at the focal spot and thus raises the temperature of the adjacent portions of the magnetic ring 44 opposite the shoe 93.
  • FIG. 3 illustrating the loss of magnetsm with rise in temperature of iron, nickel and cobalt.
  • the inversion temperature of any material having magnetic inversion characteristics is extremely critical, as indicated by vertical lines in Figure 3, so that by utilizing the momentary heating of the target at the focal spot above inversion temperature of the material of the ring 44, an unbalanced magnetic field may be created which allows the stationary magnet 81 to exert a rotating torque upon the anode.
  • the temperature of the target and of the ring 44 will fall rapidly as heat is dissipated into the body of the anode, so that the material of the ring 44, which at any instant is not in line with the focal spot, will have regained magnetism and be able to form apart of the magnetic cirpedestal portion'29.
  • the pedestal portion 29 extends within the cylindrical body of the anode and carries-anode bearings comprising, in the illustrated embodiment, a pair of roller bearings 43 and 45 in spaced-apart position on the pedestal portion 29.
  • Each bearing comprises an outer race secured preferably in the hollow pedestal, and an inner race secured on and thereby supporting a spindle 41, suitable roller members being conventionally retained between the inner and outer race portions of the bearings.
  • the spindle 41 may, of course, be secured in the bearings in any suitable or preferred fashion, although I have shown the same as being formed with" threaded portions receiving clamping nuts for clampingly securing the inner bearing races in spaced relationship on the spindle 41, the outer races of the bearings 43 and 45 being secured in the cavity 35, the outer race ofthe bearing 43 being secured in a seat 49 formed near the bottom of the cavity, said race being held in said seat by a spacing tube 5I, one end of which engages the outer race of the bearing 43 to hold it on the seat 49.
  • the other end of the tube 5I forms a seat for receiving the outer race of the bearing 45, which is held in place by a clamping tube 53 having a iiange portion.
  • the spindle 41 is thus journaled for rotation in the bear# ings 43 and 45 which are mounted on the pedestal portion 29.
  • the stem 41 has an end formed with a ange 59 outwardly of the open end vof the
  • the anode I5 is secured on said ange 59 by means of an annular mounting frame 6I, which is formed at one end for clamping on the flanged end of the stem 41.
  • the frame 6I has an end wall 63 formed with an opening dened by a lboss for receiving the end of the stem 41 outwardly of the flange 59, the frame 6I being secured on the stem 41 by means of a bolt 61 threading into the stem 41 and having ahead overlying the boss 65 to thereby clamp the wall E3 upon the ange 59.
  • the frame 6I comprises cylindrical portions preferably formed integrally with the wall 63 and extending thence outwardly of and encircling the pedestal portion 29, said frame 6I having an enlarged annular portion 69 adapted snugly to extend within the cylindrical portion 39 of the anode I5, which is formed with a shoulder 1I defin- -ing a seat for receiving the frame portion 59, the
  • I provide for the application thereto of a lubricating medium whichhas a vapor pressure suiciently low so that it will not evaporate from the bearing under the conditions of temperature and pressure prevailing within the envelope.
  • a lubricating medium a material such as barium, caesium, strontium, cadmium, chromium, copper, silver, aluminum, iron or nickel, which have a vapor pressure of the desired order whereby the lubricating medium may not migrate from a treated bearing operating under low pressure and high temperature conditions.
  • I provide for applying the selected lubricating medium in film-like form upon the bearings after the same have been assembled in place and the envelope evacuated.
  • the selected material or materials are applied upon the bearing surfaces by vaporizing the same and directing the vaporized material upon the bearing surfaces to be treated, whereby to condense the vapor as a thin film upon the working surfaces of the bearings.
  • the deposited material forms an alloy with the material of the bearings, which may be any suitable ferrous material, whereby is formed an alloy film having desired lubricating properties.
  • each loop is electrically connected, as at 8
  • an electrical heating current may be caused to flow through the wire in order to raise the temperature thereof to a point at which the lubricating material therein may be vaporized, and, as
  • the bearings may thus be lubricated, and the quantity of lubricating material applied to each bearing may be regulated by controlling the activating current delivered through each loop.
  • Each loop furthermore, may be supplied with suilicient lubricating medium to enable re-lubrication of the bearings from time to time during the service life of the device.
  • An X-ray tube having a sealed envelope, a rotarystructure in said envelope comprising a support member, a rotary member on said support member, and magnetic means on said support and rotary members in position to establish an unbalanced magnetic eld tending to rotate said rotary member on said support member in response to the application of heat to said magnetic means.
  • An X-ray tube having a sealed envelope, a rotary structure in said envelope comprising a support member, a rotary member on said support member, magnetic means on said rotary member, a permanent magnet on said support member in position to co-operate with said magnetic means whereby to turn the rotary member on the support member through the creation of an unbalanced magnetic eld when said magnetic means is heated above its magnetic inversion temperature.
  • An X-ray tube having a sealed envelope, a support member and a rotary member thereon in said envelope, an annular ring of magnetic material on said rotary member, and a permanent magnet on said support member having a portion extending adjacent and in magnetic cooperation with said ring whereby to rotate the rotary member when a portion of said ring is heated above the magnetic inversion temperature of the material thereof.
  • An X-ray tube having a sealed envelope, a support member and a rotary member thereon within said envelope, annularly disposed magnetic means on said rotary member, and a magnet on said support member in position to cooperate with said annularly disposed magnetic means, said magnetic means being normally magnetic but yielding its magnetism when heated to a critical inversion temperature whereby to establish an unbalanced magnetic field exerting a turning torque upon said rotary member upon heating portions of said magnetic means.
  • An X-ray tube having a sealed envelope, a support member and a rotary anode member thereon within said envelope, annularly disposed magnetic means on said rotary member, a magnet on said support member in position to cooperate with said annularly disposed magnetic means, and an electron emitting cathode positioned to direct electrons on said anode member at a focal zone through which said anode member including said annularly disposed magnetic means may progressively rotate whereby to progressively heat said magnetic means, said magnetic means being normally magnetic but yielding its magnetism when heated to a critical inversion temperature whereby to establish an unbalanced magnetic. eld exerting a turning torque upon said rotary member upon heating portions of said magnetic means within said focal zone.
  • An X-ray tube having a sealed envelope, a rotary structure in said envelope comprising a support member, a rotary member on said support member, and magnetic means on said suppc rt and rotary members in position to establish die and including hollow portions embracing the support member and spaced outwardly thereof, said spindle being supported in bearing means in said cavity, and magnetic means on said support member and rotary means in position to establish an unbalanced magnetic eld tending to rotate said rotary means on said support member in response to the application of heat to said magnetic means.

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  • X-Ray Techniques (AREA)
US390321A 1941-04-25 1941-04-25 X-ray tube Expired - Lifetime US2311724A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE477898D BE477898A (en, 2012) 1941-04-25
US390321A US2311724A (en) 1941-04-25 1941-04-25 X-ray tube
GB7324/42A GB556787A (en) 1941-04-25 1942-05-29 Improved x-ray tube
FR940157D FR940157A (fr) 1941-04-25 1947-01-28 Perfectionnements aux tubes à rayons chi

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US390321A US2311724A (en) 1941-04-25 1941-04-25 X-ray tube

Publications (1)

Publication Number Publication Date
US2311724A true US2311724A (en) 1943-02-23

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ID=9830940

Family Applications (1)

Application Number Title Priority Date Filing Date
US390321A Expired - Lifetime US2311724A (en) 1941-04-25 1941-04-25 X-ray tube

Country Status (4)

Country Link
US (1) US2311724A (en, 2012)
BE (1) BE477898A (en, 2012)
FR (1) FR940157A (en, 2012)
GB (1) GB556787A (en, 2012)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2489080A (en) * 1946-07-17 1949-11-22 Hartford Nat Bank & Trust Co X-ray tube comprising a disk-shaped rotary anode
US3243636A (en) * 1963-01-30 1966-03-29 Tubix Soc Rotary anode for X-ray tubes
US3502926A (en) * 1967-03-24 1970-03-24 Hitachi Ltd Rotating anode x-ray tube with magnetic damper
US5086442A (en) * 1990-03-28 1992-02-04 Siemens Aktiengesellschaft Magnetic coupling for a rotating X-ray tube

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2489080A (en) * 1946-07-17 1949-11-22 Hartford Nat Bank & Trust Co X-ray tube comprising a disk-shaped rotary anode
US3243636A (en) * 1963-01-30 1966-03-29 Tubix Soc Rotary anode for X-ray tubes
US3502926A (en) * 1967-03-24 1970-03-24 Hitachi Ltd Rotating anode x-ray tube with magnetic damper
US5086442A (en) * 1990-03-28 1992-02-04 Siemens Aktiengesellschaft Magnetic coupling for a rotating X-ray tube

Also Published As

Publication number Publication date
GB556787A (en) 1943-10-21
BE477898A (en, 2012)
FR940157A (fr) 1948-12-06

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