US2232831A - X-ray tube - Google Patents

X-ray tube Download PDF

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Publication number
US2232831A
US2232831A US222520A US22252038A US2232831A US 2232831 A US2232831 A US 2232831A US 222520 A US222520 A US 222520A US 22252038 A US22252038 A US 22252038A US 2232831 A US2232831 A US 2232831A
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US
United States
Prior art keywords
tube
anode
ball
bearing
bearings
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
US222520A
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English (en)
Inventor
Tuuk Jacob Harmannus Van Der
Bouwers Albert
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
Original Assignee
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
Application granted granted Critical
Publication of US2232831A publication Critical patent/US2232831A/en
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
    • H01J35/20—Selection of substances for gas fillings; Means for obtaining or maintaining the desired pressure within the tube, e.g. by gettering
    • 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
    • H01J2235/16—Vessels
    • H01J2235/165—Shielding arrangements
    • H01J2235/168—Shielding arrangements against charged particles

Definitions

  • Rotary anodes of X-ray tubes have to satisfy the condition that in any position of the tube it must be possible to keep them in rapid motion by means of a very slight torque.
  • this journalling involves such difculties that the use thereof, at least for anodes of the heavy type, has proved in practice to be impossible.
  • Experiments in this respect were unsuccessful because the ball-bearings, after having 'operatedfor some time, exhibited a highly increased friction with the result that the speed of rotation rapidly decreased and the tube became unt for use.
  • the use of bearing lubrication seemed a priori to be excluded since one always aimed at avoiding as carefully as possible that even traces of grease should remain behind in the high-vacuum chamber.
  • the present invention affords for the irst time a practical ⁇ solutionof the problem of utilising ball-bearings for journalling X-ray anodes of the heavy type.
  • the anode During operation of an X-ray tube the anode, more particularly the rotary anode adapted to be submitted to a high load, is thermally loaded, which results in an increase of the temperature of the bearing members ⁇ from which, as from any other part of the anode, gases may be liberated if previously they have not been removed therefrom.
  • the ball-bearings cannot sustain the high temperature required for the careful removal of occluded gases and besides, during operation of the tube, they are very sensitive to heating.
  • the above diliculties are overcome by making the thermal conductivity of the mechanical connection between that part of the anodelon which during operation the heat is developed and the bearing parts so small that from the thermally loaded parts towards the bearings conduction of heat does practically not occur, and by connecting the bearing parts in a satisfactorily heat-conducting manner to members which can be cooled during operation.
  • a heavy anode i. e.
  • an anode wherein the metal exposed to the electron bombardment is connected in' a satisfactorily heatconducting manner to a metal mass to which the heat is transferred and in which it can be dispersed at once, has, in contrast with the disadvantage it offers to rotatable journalling due to its weight and size, the advantage that its tempe'rature remains several hundreds of degrees centigrade' below the temperature which is ac-l quired during operation by a light anode, i. e. an
  • the ball-bearings of the rotary anode with a lubricant which has so low a vapour pressure that it has no appreciable harmful influence on the high vacuum in the tube.
  • the known so-called cock grease which is used by persons in the physical art for the sealing of exhausted vessels, more particularly of cocks, but hitherto only for this purpose, is utilised as a lubricant for the ball-bearings.
  • the suspension of the comparatively heavy ⁇ rotary body may be effected by means-of a thin-walled tube which is secured between the front of the rotary bearing natively extend from the front of the rotary bearing member backwards to the anode end of the tube and be secured'to the rotary anode body at a point remote from the anode target.
  • a suitable material for the intermediate member is ferro-chromium, which'possesses both a great mechanical rigidity and a slight heat conductivity.
  • the thin-walled metallic tube should preferably be protected against electronv bombardment since, on account of the small thickness lof itswall, it might be heated to an admissibly high temperature even by a stream of electrons of comparatively low intensity.
  • the ballbearings are provided at points which communicate with the discharge chamber proper only by lmeans of narrow channels having cool walls.
  • the tube may alternatively be provided with a device which produces a getter at an arbitrary instant after the exhausted vessel has been sealed off.
  • Fig. 1 represents a longitudinal section of a tube having an intermediate member which extends from the bearing members towards the cathode.
  • Fig. 2 represents an anode construction in which the intermediate member extends backwardly from the foremost part of the bearing.
  • reference numeral I denotes a metallic portion of the wall of a tube.
  • the portion 3 has a re-entrant portion 4 which supports a. cathode construction 5.
  • the portion 2 also has a short re-entrant portion 6 the edge of which is sealed to a metallic body 1.
  • ball-bearings 9 and Il! in which a rotary shaft I I is journalled.
  • the foremost end of the shaft II is provided with a disc I 2 which carries a thin-walled metallic tube I3.
  • This tube constitutes an intermediate member between the rotary bearing member and the rotary anode body I4.
  • This body consists of a comparatively heavy piece of copper provided with a backwardly extending cylindrical extension I5 which acts in a manner known per se as the rotor of an electric motor.
  • the glass portion 2 is surrounded by an electromagnetic stator (not shown in the drawing) which sets up the magnetic rotating field that causes the anode to rotate.
  • the front of the body I4 has secured to it a tungsten disc I6 which is turned towards the cathode 5, said disc being in satisfactory heat-conducting connection with the body I4.
  • the heat produced in this disc during operation of the tube is directly distributed over the mass of the body I4 whose temperature may increase in the case of prolonged operation, for example to 500 C. It cannot bring about, however, an appreciable increase in the temperature of the ballbearings and this for the following reasons.
  • the thin-walled metallic tube I3 which preferably consists of ferro-chromium and has a wall thickness, for example, of 0.5 mm., transfers, due to its slight thermal conductivity, only a small amount of heat to the ball-bearings. Ii the bearings were mounted so as to be thermally insulated, yet even a very small supply of heat could increase their temperature in the long run to an appreciable extent, which might result in that the lubricant decomposes or vaporizes and that the ball-bearings, which are only partly deprived of occluded gases, become jammed.
  • the ball-bearings are, however, in heat-conducting connection with the member 1 which can be cooled during operation and which takes up at once all the heat which is still transferred by the metal tube I3 to the bearings.
  • the ball-bearings consequently remain cold and the grease as well as the bearings themselves do not give rise to inconveniences.
  • the heat radiated by the cylindrical portion I5 of the rotary anode body is partly taken up by the member 'I which permanently be cooled, so to speak, may be thermally grounded during operation (if required, by additional means, for example by bringing it into contact with a liquid or gaseous cooling medium or a solid cooling body).
  • the reentrant portion 6 has sealed to it a metallic plate E, which carries a cylindrical casing I9 for the ball-bearings 9 and ID which are provided with grease.
  • the metallic plate 8 and therefore the casing I9 with the ball-bearings may be kept at a low temperature during operation by artificial cooling.
  • the disc I2 mounted at the end of the shaft II has secured to it a metal tube II which has a thickness, for example, of 0.5 mm., said tube extending backwardly and being secured at its other end to the hindmost edge of the cylindrical portion I5 of the anode.
  • This tube is preferably made of ferro-chromium since this metal has a great mechanical rigidity and a slight thermal conductivity.
  • the metal tube I'I forms a screen which prevents heat from being radiated from the cylinder I5 towards the bearing members.
  • the construction of the tube as shown in Fig. 1 is suited for taking radiographs and for fluoroscopy.
  • the anode according to Fig. 2 does not surround, at a slight distance, as in Fig. 1, a body adapted to take up the heat, and is less suitable for prolonged operation.
  • the aperture in the front-side of the anode body I4, which serves to attach the metal tubes I3 or by means of a suitable tool to the disc I2, is closed by a screw I8 so that the electrons are prevented from entering into the chamber enclosed by the body I4 and from heating the thinwalled metal tube I3 or I'I.
  • the cathode construction consists of a tube which acts as a concentrating device and from which a portion is separated by a partition 22.
  • This portion contains a heating helix 23 and a getter receptacle, for example a copper tube filled with barium.
  • the heating body may be heated by a current supplied thereto by wires 24 and 25 in order to vaporize the getter.
  • the condensed vapour deposits on the inner wall of the chamber separated by the partition 22.
  • This getter chamber communicates by means of an aperture 26 with the remainder of the high-vacuum chamber so that gases or vapours which may escape, for example, from the grease in the ball-bearings or from the bearings themselves and which would deteriorate the vacuum, are at once absorbed and rendered harmless by the getter in the chamber below the disc 22.
  • the current supply Wire 2'! as well as the Wire 24 serve for the supply of heating current to the incandescent body 28 of the cathode.
  • the concentrating device of the cathode comprises by a screen 29 which surrounds the foremost anode portion an'd prevents electrons from passing from .the discharge chamber into the remainder of the evacuated space, harmful discharges which might be produced by such leakage electrons being thus avoided.
  • the screen 29 and the metallic wall portion I have windows 30 and 3
  • the Window 30 is closed by a beryllium disc Whereas the metallic portion I,
  • An X-ray tube comprising an envelope, a cathode, a rotatable anode of the heavy type, a member adapted to be cooled lduring operation of the tube, a ball-bearing supported from said member, a second member of low heat-conductivity supporting said anode from said bearing to prevent heating of the ba'll-bearing and a lubricant of the type of cock grease on said ballbearing.
  • An X-ray tube comprising an envelope, a cathode, a rotatable anode of the heavy type, a ball-bearing, supporting means of good heat-conductivity for said bearing, a thin-walled tube of a metal of low heat-conductivity supporting said anode from said bearing to prevent the transfer of heat from the anode to the Iball-bearing, and means to protect said tube from electron bombardment during the operation of the X-ray tube.
  • An X-ray tube comprising an envelope, a cathode, a ball-bearing, a rotatable anode of the heavy type, means of poor heat conductivity supporting said anode from said ball-bearing, a lubricant on said ball-bearing, and gettering means Within said envelope for removing any gases or vapors liberated by the ball-bearing and lubricant.
  • An X-ray tube comprising an envelope, a cathode, a rotatable anode, a ball-bearing supported from said envelope, means of low heatconductivity supporting said anode from said bearing to Iprevent heating of the ball-bearing, and a lubricant on said ball-bearing, said lubricant having a low vapor pressure.

Landscapes

  • X-Ray Techniques (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • Rolling Contact Bearings (AREA)
US222520A 1937-08-02 1938-08-01 X-ray tube Expired - Lifetime US2232831A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEN41029D DE748187C (de) 1937-08-02 1937-08-02 Roentgenroehre mit auf Kugeln gelagerter Drehanode

Publications (1)

Publication Number Publication Date
US2232831A true US2232831A (en) 1941-02-25

Family

ID=25759672

Family Applications (1)

Application Number Title Priority Date Filing Date
US222520A Expired - Lifetime US2232831A (en) 1937-08-02 1938-08-01 X-ray tube

Country Status (8)

Country Link
US (1) US2232831A (fr)
BE (1) BE429488A (fr)
CH (1) CH204369A (fr)
DE (1) DE748187C (fr)
FR (1) FR841545A (fr)
GB (1) GB501253A (fr)
NL (1) NL52715C (fr)
SE (1) SE97777C1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2430800A (en) * 1943-10-02 1947-11-11 Gen Electric X Ray Corp Rotating anode construction
US2812462A (en) * 1953-05-18 1957-11-05 Gen Electric Anode structure
US20080240359A1 (en) * 2007-03-28 2008-10-02 Jtekt Corporation Rolling bearing for x-ray tube and x-ray tube apparatus

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE448042A (fr) * 1941-11-20
DE891430C (de) * 1942-08-15 1953-09-28 Mueller C H F Ag Drehanode fuer Roentgenroehren
DE1062828B (de) * 1955-04-23 1959-08-06 Phoenix Roentgenroehrenwerk Ru Roentgenroehre mit tellerfoermiger Drehanode
DE1041173B (de) * 1957-04-02 1958-10-16 Phoenix Roentgenroehrenwerk Ru Drehanodenroentgenroehre mit waermegeschuetzten Lagern fuer die Drehanode
DE1099095B (de) * 1958-07-17 1961-02-09 Siemens Reiniger Werke Ag Drehanoden-Roentgenroehre
DE102006005242A1 (de) 2006-02-03 2007-08-16 Wilhelm Dr. Irvine Degen Rüttleranordnung und Verfahren zur Herstellung von Materialsäulen im Boden

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE296334C (fr) *
BE372145A (fr) * 1927-01-18
DE579437C (de) * 1929-05-26 1933-06-26 Hugo Stintzing Dr Hochvakuumgeraet
DE603896C (de) * 1932-05-30 1934-10-11 C H F Mueller Akt Ges Roentgenroehre, deren Antikathode aus einem feststehenden, gut waermeleitenden Teil besteht, um welchen sich der von den Elektronen getroffene Teil bei seiner Rotation dreht
DE623027C (de) * 1933-01-26 1935-12-11 Hugo Stintzing Dr Einrichtung zur Erhoehung der Belastbarkeit von metallischen Roentgenroehren mit relativ zum Gehaeuse drehbarer Anode
US2030561A (en) * 1933-03-28 1936-02-11 Westinghouse Lamp Co X-ray tube
DE611336C (de) * 1933-06-24 1935-04-09 Siemens Reiniger Werke Akt Ges Roentgenroehre mit relativ zum Roehrenkoerper rotierender, zur Waermeabstrahlung bei hohen Temperaturen geeigneter Anode

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2430800A (en) * 1943-10-02 1947-11-11 Gen Electric X Ray Corp Rotating anode construction
US2812462A (en) * 1953-05-18 1957-11-05 Gen Electric Anode structure
US20080240359A1 (en) * 2007-03-28 2008-10-02 Jtekt Corporation Rolling bearing for x-ray tube and x-ray tube apparatus

Also Published As

Publication number Publication date
FR841545A (fr) 1939-05-22
GB501253A (en) 1939-02-23
NL52715C (fr)
BE429488A (fr)
CH204369A (de) 1939-04-30
DE748187C (de) 1944-10-28
SE97777C1 (sv) 1940-01-09

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