Sept- 17, 1946- A. vERHoEl-F I 2,407,857 ` X- RAY TUB E Filed Jan. 11,; 194s ' i 16, I il' y@ a x sa :5154 ¿zizi/l“ 2:46 a; iff»A âme/whoa, Aàrîanu s Vath cef? ,a _ 9519/ . bho z 1.1 2,407,857 Patented Sept. 17, 1946 UNITED STATES PATENT OFFICE 2,407,857 X-RAY TUBE Adrianus Verhoeff, Eindhoven, Netherlands, as signor to Hartford National Bank & Trust Com pany, Hartford, Conn., trustee Application January 11, 1943, Serial No. 472,068 In the Netherlands February 27, 1941 10 Claims. (Cl. Z50-«143) 2 1 X-ray tubes having a comparatively great mean load require measures for cooling the anode. Various means may be used to withdraw heat from the anode. In tubes for diagnostic work the operating temperature of the anode must re main far below the maximum admissible anode temperature to prevent heat shock. The usual expedient is to fix a heat conductor to the anode, for example conductor shaped in the form of a y metal rod which extends through the wall of the tube behind the anode and has a radiating sur face outside the tube. With tubes comprising a safety jacket the pres ence of such a heat radiating member having the potential of the anode is inconvenient for several l. 5. reasons and it has therefore previously been sug gested that the heat transfer should be effected by radiation from the anode towards that part of the tube wall which surrounds the anode instead of being effected by transmission. By this wall ` which is generally maintained at earth potential, the heat can be readily transmitted to the sur rounding air or to a cooling medium. ` Although this means of cooling the anode yielded satisfactory results thanks to a combina- ‘ tion of various measures it is surpassed in effi ciency by the arrangement of an X-ray tube ac which engages the walls of the intermediate space with slight pressure and transmits the heat from one wall to the other. This affords good heat conduction and enables free expansion and con-, traction due to temperature changes. This re silient member may be constituted for example by a cylinder of corrugated sheet metal. The principle of the invention may be carried -into practice in various ways, The insulator may form part of the outer Wall of the tube :and thus serve to absorb both the electric voltage and the air pressure. ‘ As an alternative, the insulator may be wholly arranged within the vacuum of the tube., In this case, the heat has therefore still to `be conducted from the insulator to that part of the outer wall of the tube by which it is surrounded and which in this case may be of metal. In order to assist good heat transmission between the insulator and the tube wall, it is preferable that a resilient member, for example a metal sleeve of corrugated sheet metal should be arranged in the manner mentioned before for the conveyance of the heat from the anode to the insulator. The insulator may be made of ceramic mate rial, for example china. This material is capable of withstanding heat, may be readily freed from gases and is Vgenerally a suilicient heat conductor ' and electrical insulator. » ‘ In the latter the peripheral surface of the anode is enclosed by a stationary body constituted 30 In the construction according to the invention the heat is conducted away by a body which is re wholly or in part by a high-tension insulator quired to be a good electrical insulator. Although having a sufficient heat conductivity and surface as a rule the heat conductivity of electrical in of contact with the anode to conduct a quantity sulators is much less than that of metals, suffi of heat of at least 100 watts at a temperature dif cording to the invention. ference of not more than 300° C. away from the cient heat can be conducted away in this case by the insulator due to the fact that the direction in which the energy ñows off is normal to the surface and this latter may be made comparatively large so that but little heat per unit of section hence not in an axial direction, the body may con sist wholly of insulating material or may consist 40 needs to be conducted away. Moreover, the heat has only to traverse a comparatively short path. of alternating laminae of conducting and insulat The conditionsare consequently just the reverse ing materials. as compared with tubes having a cooler at the end, It is essential that the insulating material be because in the latter case the section of the capable of withstanding the full tension existing (metal) heat. conductor is much smaller and its between the anode and earth, said tension being length is much greater as compared with the tube about half the operating voltage of the tube.` according to the invention. It is dimcult to manufacture and place in posi In order to increase the surface over which theV tion an insulator that fits so accurately around heat dissipation is distributed the anode as a the anode that a satisfactory heat conducting, contact may be set up between the wall of the p 50 whole need not be made particularly long but it is suflicient to shape it into the form of a hollow anode and that of the insulator. According to tube, for example a cylindrical tube, which dis .the invention, this difficulty can be obviated by sipates the heat and transmits it to the surround leaving some intermediate space between the ing body and which comprises a bottom or inter anode and the insulator and arranging >therein vanode to the space outside the vacuum of the tube. The term “wholly or in part” is to be under stood to mean here that in a radial direction, and a resilient member of good‘heat conductivity mediate wall carrying the anode mirror. 2,407,857 3 4 The circumstance that the anode is in heat conducting contact with a body7 surrounding it in it, the body 5 is locally thinned at I4, the may be taken advantage of to cause it to be so supported by this body that that part of the wall which seals the tube at the end behind the anode is not given any mechanical load by the anode weight. This latter part which thus only serves for insulation and for sealing the vacuum'must give passage to the current supply lead of the anode which may therefore be very thin so that heat is not conducted away along this path. The tube end which can be closed by a cable end piece thus remains cool due to the fact that a direct heat-conducting connection to the anode is miss mg. .For sealing the tube at the ends use may also be made of disc-shaped glass-like members com sleeves 4 and 5 have a corresponding aperture formed in them and the metal wall I comprises a window closed by a thin small glass plate l5. The heat is rapidly dispersed about the block t and thence it is transmitted to the cylinder l. The latter gives theanode a large surface of con tact with the resilient sleeve 6 which in turn is in contact over a large surface with the china part 5. Although the heat transmitted through each unit section of the part 5 is less than if it were made of metal the large extensiveness of the sec tion which contributes towards the conveyance of heat and the short distance through which the heat has to be conveyed enable the heat to escape rapidly. It is true that the spaces between the anode and the china part 5 and those between the latter glass”) which permits metals and insulating ma and the tube wallare only filled in part 'but the terials having widely diiïerent coeñ‘icients of ex 20 gripping sleeves è and 5. may be made of a metal pansion to be sealed together to thereby obtain a having a much higher specific conductivity than vacuum-tight seal. the insulator 5. In order that the invention maybe clearly The outside of the wallfi may, if necessary, be understood _and readily carried into eiîect it will cooled artiliciallyv by a circulating gaseous or liq now be set out more fully with reference to the 25 uid cooling medium or by the provision of cool accompanying drawing in which two forms of ing ribs. ' construction of X-ray tubes according to the in The withdrawal of heat from the wall l to the vention are shown in section. By means thereof glass sealing pieces is avoided by the presence of Y so‘me details obtained by further development of' thinned` edges l5. ' In addition, radiation of heat the invention will be mentioned. 30 from the anode to the sealing piece 2- is prevented ' Fig. l is a longitudinal sectional view of an X bythe bottom Il of the insulator 5'. The current ray tube having a heat-conducting insulating lead 9 is so thin and klong that no appreciable body arranged entirely within the tube. heat'transmission occurs alongr it. The glass seal prising finely divided cavities (so-called “sponge Fig, 2 is a cross-sectional View of the same tube ing piece 2 and the cable end-piece to be arranged taken on the plane I-I. 35 thereon are thus safe-guardedV against heating. Fig. 3 shows a tube in which the heat conduct ' With X-ray'tubes of they construction hitherto ing insulating body constitutes the outer wall of in use the anode is supported by the re-entrant the tube. glass edge ofthe tube wall. ’ Referring to the drawing, 1 designates an ex The invention permits‘a sturdier construction hausted cylindrical metal vessel closed at the ends 40 to be obtained. It enables the anode to be car by glass sealing pieces 2 and 3. A cylindrical body 5 of electrically insulating material, for example china or other ceramic material is gripped in the metal vessel b-y means of a resilient sleeve 4 of corrugated sheet metal of good heat conductivity',A for example copper. The anode of the X-ray tube is gripped within the body 5 by a likewise resilient sleeve B of cor rugated plate-shaped material. The anode com prises a cylindrical part 'lv and a block 8 both of metal kof good heat conductivity, for example copper. The cylinder 1 may be shrunk round the block 3 so as to afford good heat conduction. The anode has secured to it a supply conductor ried solely by therside wall of the tube by uniting the resilient sleeves 4 and'ß and the insulator 5 with the anode and the metal wall l to form an Aunshakable unit, forY example by gripping, as shown. The glass part 2 of the wall which seals the tube at the end' behind the anode is thus not given any mechanical load by the weight of the anode and thus the risk of breakage which is al ways impending in other tubes is averted. The metal cylindricalV body l is also used for a further purpose. It is lengthened towards the side ' of the cathode. This arrangement has the Vad vantage that the part extending to the other side can be shorter and the heat is more readily' dis 9 _which is passed through the sealing piece 2 55 tributed about the entire length of the cylinder by means of a small metal disc li) sealed to the glass. The cathode Il is secured to the sealing piece 3 and has a normal construction,` details such as the leading-in wires sealed in the pinch 20 and the filament being therefore omitted in 60 the drawing. - because it can flow from the centre to both sides moreover, the tube acts as a screen against sec ondary electrons. In order that this function may be most effective the cylindrical body is pro vided with a bottom i8 which‘ has, of course, formed in it an aperture for the passage of the - When the tube is in use the electrons are pro beam of cathode-rays. In addition, this aperture pelled by the electric neld between the two elec has an upright edge i9 turned towards the anode trodes at such a speed against the anode mirror mirror in order also to retain electrons moving I2 that X rays are generated in situ. Essentially, 65 in a direction at a large angle with the axis of l however, the energy of the electrons is converted into heat and secondary electrons are also dis lodged. the tube, such as tertiary electrons proceeding from the inner wall of the cylinder l. In so far as charged particles may still emerge The X rays are absorbed for the greater part `from the discharge space they are retained by the by the wall of the tube and other parts (all of 70 insulator 5 which for this purpose is lengthened which are not shown) which jointly surround towards the cathode side to the extent of sur the anode and in part may be provided deliber rounding the discharge path and, for thel avoid ately for this purpose. A narrow beam of rays ance of harmfulcharging _may be provided on is transmitted. For this purpose the cylindrical the inside with a thin conducting layer. V part 1 of the anode 8 has an aperture i3 formed 75 The anode of the X-ray tube shown in Fig. 3 2,407,857 _ is formed by a block 2| and a cylinder 22, the block 2| carrying the anode mirror 23. ` Again, the cylinder 22' is mounted » _ , 6 bular envelope, an anode member having a, heat generating portion and being arranged within said envelope with its peripheral surface adjacent an in sulator 25 >by means of a resilient sleeve 24 of corrugated »sheet metal. . 4. An X-ray ¿tube comprising an evacuated tu " to the inner surface of the envelope, and means The insulator 25 constitutes the envelope of the tube, and glass sealing pieces 26 and 21 are sealed to theedges of the insulator at 28 and 29. The to directly connect the said adjacent surfaces in heat conducting relationship co-mprising an elec trical insulating member and a resilient member.;V insulator may be of china or of similar ceramic of good heat-conductivity surrounding anode member and interposed between the adjacent surfaces, the heat generated at portion being- transferred to‘said envelope material to which glass can be fused. The anode is supported by the insulator 25 only and the seal ing piece 2E solely serves for vacuum sealing the envelope and for the leading-through of the sup ply conductor 3D to the anode. For the purpose said said said in a radial direction from the anode member and sub stantially entirely by conduction through said of increased safety the insulator may be coated 15 on the outside with a layer of conductive mate insulating and'resilient members. the glass Sealing piece 21 is sealed. ramic sleeve member and a cylindrical corrugat ' ' 5. An X-ray tube comprising an evacuated tu bular envelope, a hollow cylindrical anode mem rial (not shown). a ‘ Similarly, the sealing piece 21 serves solely for ber having a wall portion provided with an anode sealing the vacuum and for leading-through of mirror and being arranged with its peripheral the supply leads 3l and 32 to the cathode. The 20 surface adjacent to the inner surface of the en latter are secured to studs which are arranged velope, and means to directly connect the said in a metal plate 35 from which they are insulated adjacent surfaces in heat conducting relation by glass beads 33 and 34 t0 the edge of which ship comprising an electrically insulating ce The cathode shell 36 is supported within the 25 ed sheet-metal member 'surrounding the cylin insulator 25 in a manner similar to the anode drìcal anode member and interposed between the by means of a disc 31 having a bent-over edge said adjacent surfaces, the heat generated at the 38 which is rendered resilient by the provision of anode mirror being transferred to `said envelope a a plurality of slits 39. in a radial direction from said anode member The heat produced in the anode in the use of 30 and substantially entirely by conduction through the tube passes to the cylinder 22 and hence is said insulating and sheet-metal member. led by the resilient sleeve 24 through a large sec 6. An X-ray tube comprising an evacuated en tional surface of the insulator 25 towards the velope, and a cathode member, an anode mem outer surface of the tube, where it is dissipated ber spaced apart and enclosed within said en by radiation or carried away by other means. 35 velope, said anode member comprising an anode What I claim is: mirror, a hollow cylindrical element enclosing 1. An X-ray tube comprising an evacuated the anode mirror, and means to collect secondary tubular envelope, an anode member having a electrons from the anode mirror comprising a heat-generating portion and being arranged portion of the cylindrical element extending be within said envelope with its peripheral surface 40 yond the said mirror towards the cathode mem adjacent to and spaced from the inner surface of ber, said cylindrical element being arranged the envelope, and means to directly connect the within the envelope with its peripheral surface said adjacent surfaces in heat conducting rela adjacent to the inner surface of the envelope, and tionship comprising a memberof good heat con-Y means to directly connect _the said adjacent sur- ` ductivity whereby to transfer the heat generat ’faces in heat conducting relationship comprising ed at said portion to said envelope in a radial di a member of goed heat conductivity whereby to rection from the anode member and substan transfer the heat generatedV at the anode mirror tially entirely by conduction. 2. An X-ray tube comprising an evacuated tu bular envelope, an anode member having a heat generating portion and being arranged within said envelope with its peripheral surface adja to said envelope in a radial direction `from said cylindrical element and substantially entirely by 50 conduction. 1. A'n X-ray tube comprisingy an evacuated cy lindrical metal envelope, an anode member with cent to the inner surface of the envelope, and means to directly connect the said adjacent sur-4 in said envelope comprising a cylindrical metal sleeve arranged within the envelope with its pe faces in heat conducting relationship comprising 55 ripheral surface adjacent to the inner surface of a resilient member of good heat conductivity, the the envelope, an anode mirror within said sleeve heat generated at said portion being transferred and secured to the inner wall thereof, said- anode to said envelope in a radial direction from the sleeve having a portion which extends beyond anode member and substantially entirely by con the anode mirrorand is provided ‘with an aper V duction through said resilient member. ture in the wall thereof adjacent to the anode 3. An X-ray tube comprising an evacuated tu- ' mirror and which comprises a flange portion bular envelope of electrically insulating and good having its edge inwardly facing the anode mir heat-conducting material, an anode member ror, and means to directly connect the said ad having a heat-generating portion and being ar jacent surfaces in heat conducting relationship, ranged within said envelope with its peripheral 65 said means comprising a cylindrical electrical surface adjacent to the inner suface of the en velope, and means to directly connect the said insulating ceramic member surrounding the anode member 'and extending beyond the said adjacent surfaces in heat conducting relation flange portion thereof, a cylindrical corrugated ship comprising a resilient member of goOd heat sheet metal member interposed between and conductivity interposed between and contacting 70 contacting the adjacently positioned surfaces of the said adjacent surfaces, the heat generated at the ceramic and anode members and a cylindri- ‘ said portion being transferredv to said envelope in cal corrugated sheet metal member interposed a radial direction from the anode member and between and contacting the adjacentlyl posi substantially entirely by conduction through said tioned surfaces of the ceramic member and the 75 envelope, the heat generated at the said anode resilient member. 2,407,857 7 8 , mirror `being transferred to the envelopein a. radial direction from the anode member and sub- « stantially entirely by conduction through said cylindrical corrugated members and said ceramic member. - Y age supply conductora for »the anode member passing through said. sealing member, and means to directly connect the said adjacent surfaces in heat conducting relationship comprising -a mem. ber of good heat conductivity whereby to trans fer the heat generated at .the said portion of the 8. An X-ray tube comprising an evacuated tu bular envelope, an anode member having aheat anode member to said envelope in a radial di `generating portion and being yarranged >within rection from the anode member and substantial yëyaid envelope with its peripheral surface >adja lyventirely by conduction, said supply conductor cent to and spaced from the inner surface of the 10 having a poor heat conductivity andpreventing heat conduction from the anode member to said envelope, said anode member being supported sealing member. Y » . within said envelope substantially entirely by the 10. An X-ray tube comprising an evacuated surrounding portion of the envelope, and means tubular envelope', an anode member having a to directly connect the said adjacent surfaces in heat conducting relationship comprising a mem 15 heat-generating portion and being arranged within said envelope with its peripheral surface ' ber of good heat conductivity whereby to vtrans adjacent to and spaced from and electrically in fer the heat generated at the said portion of the sulated from .the inner surface >of the envelope, anode member to the envelope in a radialdirec and means to directly connect the said adjacent tion from the anode member and substantially entirely by conduction. 20. surfaces in heat conducting relationship co-m- Y prisingv a member of good heat conductivity 9. An X-ray tube comprising an evacuated tu whereby to transfer the heat generated at said bular envelope, a sealing member closing one end of the envelope, an anode member having a heat generating portion and being arranged within the envelope with its peripheral surface adja cent to the inner surface of the envelope, a volt portion to said envelope in. a radial direction from the anode member and substantially entire ly by ccnduction. Y v » ‘ ADRIANUS VERHOEFF.