US2259037A

US2259037A - Cooling x-ray tubes

Info

Publication number: US2259037A
Application number: US320323A
Authority: US
Inventors: Edward B Graves
Original assignee: Picker X Ray Corp
Current assignee: Picker X Ray Corp
Priority date: 1940-02-23
Filing date: 1940-02-23
Publication date: 1941-10-14
Anticipated expiration: 1958-10-14
Also published as: GB551895A

Abstract

551,895. Cooling R÷ntgen-ray tubes. GRAVES, E. B. Sept. 11, 1941, No. 11651. [Class 98 (i)] [Also in Group XL] In a liquid-containing cooling jacket for an X-ray tube means are provided for causing circulation of the liquid to conduct the heat to the wall of the jacket, and also means for causing a flow of cooling fluid against the external surface of the jacket. As shown, the tube is mounted in a shell 5 filled with oil or other insulating and cooling liquid, which is circulated by an impeller 14 operated by a motor mounted on a cap closing the end of the shell. A tubular member 18, which may be of lead or bakelite, serves to guide the liquid flowing towards the impeller into contact with the tube, and that returning from the impeller into contact with the wall of the shell; it serves also as a screen for the rays. The shell 5 is surrounded by a metal jacket 20, between which and the shell air is caused to flow by a fan or blower 23 in a casing 24 mounted on the jacket.

Description

Oct. 14, 1941. E. B. GRAVES COOLING X-RAY TUBES Filed Feb. 25, 1940 FIG-l gal/7% INVENTOR DWARD B. GRAVES ATTOR FIG-2 NEYE Patented Oct. 14, 1941 .to Picker IX-Ray Corporation Waite Manu- "facturing Division,lnc., Cleveland, Ohio, a corporation of Ohio 'Avpiplication Februany 23, 1940, Serial No. 320,323

'6 Claims.

This invention relates to cooling vof 'i Xe'ray tubes.

One Object of the invention isto lprovide'improved means for cooling an X-ray' tub adapted rapidity so that neither the tube ncr its'mountvingiparts or iconnectionsrea'ch undesirable high mosphere, as the case may be.

A further object is "to provide an improved X-ray tube mount 'of ig'en'e'rally standard' fo'rm with the tube enclosed in a shell 'within which an'insulating and more or less heat conducting fluid is circulated, said shell being surrounded by an enclosing c'a'sin'g forming 'two 'closely contiguous 'walls," and 3 Hence an annular chamber, through which air 'or ethersuitable fluid may be caused to "flow ffor 'cooling 'pur'p'ose's.

Further objects of the invention are in'part 'obvious'an'd in; part"will appear mor detail hereinafter.

In the drawinggwhich irepresents one- 'suitarivle embodiment of i the invention, Fig. 1i's= a centr al "longitudinal section; Fig. :2 isan r end view from the right in'Fig. 1; Fig. 3"-is" asectional-elevation on'appr'oximately th line 3' 3, Fig. 1; amil "The 'X='ray tube -itself requires no extended description because it is' of usual form, including the hollow glassbody l in which is 'mounted the anode 2, usuallyarheeivy piece "Of cGpperei-ther hollow' or solid," carrying theinlafd' target 7 3, the outer 'end of said -:a'n'o'cle extending outthrou'gh one of:the"endsof the T'ho'llowigla'ss body. The anode of course is an "excellent "conductor'o'f the heat producedjwhich is dissipated l'argely "from that end of the anode Whichextiands beyond -the glass body.

The tube" body is 'suitablymiount'e'd in' anenclosing shell, marked generally 5, usualy made I of aluminum, an aluminum alloy,' or other-"suitable light material, provided on oneisid'e,"'opposite the target 3, with the usualwind'ow "6, and on its to dissipate the generated heat with sufiioient -;55

-fhavingcavities 8nn whichtane inserted-terminals '(notishown) connectedrto theifl'ead'W-iresT-mr the tubercircuits.

Erie and i of ithe shell supports the .usual .cexipans'ion 'idevice, such' as the frsylphon :b'elIews F9, Farranged ito 'compensateforvariations; in volume 10f the fluid iwi'thin'fth'e fshell Tas :the result :of changes 'in temperature for tone T635011 :or sanother. Frequently such expansion :chambers :haverbeeni'mounte'd 'onezin each endrof the tubu- 'la'rishllfibut according to the ipresentninvention but a single r'expansion z'device iis employed, the other fend iio'f ithe: shell rserving 'tofisupport fluid 'circutatingzmeansas will 'moreiffullylappear hereafter.

The tube, of course, Sis rigidly --but rremovably mountedwithin the shell, so tthatwhetargettis 'in its :central ilongitudinal faxis 1 and opposite "the centerio'f the window -6. Forthis purpose "the opposite ends of -th tube-fiaremounted in sup- .p'orts' 0, l I iattac'h'e'd rto'the' stationary 'Ish'elr 'or to a 1 part :fix'ed ith'eretowsuch -:as to the sleeves 1'2 into'whichtnewire carrying terminals are in- :serted. Any Rather "suitable 'Itub'e supporting 125 .means m ay :fbe employed.

:The Shell "chamber l3 i's'f-fi'lled 'with 'a 1 suitable insula'ting'liqui'd which iaiso is a more "or less :efii'cient heat fcarrier,"'such as a suitableroil, and ftol'more' rapidly fdissipate'ithe' heat means is prowithin chamber l3. The means shownicompris'es any "suitable oil movin-g device, such as the imp'eller I4imounted-on the shaftI 5= o r an'operatin device, such asan electric motor IB, rigidly imounted withln a'closing cap H 'on'on'e end of fth 'rtubular sh'ellti. The motor and "impeller preferably are"mounted-' coaxially =with the "shell -axis,:a'nd="n1eans :isrprovided' 'wherby said imqaeller, when opeiatingfikeeps' the entire =b'0dy of 0 the foil cohstantly in' mo'tion, circulating an of iitgatfone time*ior another,"=into close orihtimate heat conducting relation with the shell wall 5, e'so that -th-e heat' carried by thecoil may be abisoribed by andthen 'radiated from said wall and thus "become dissipated.

The i'rneans shown tor "this purpose is a tubular shield or guide lB,'-which-*may"be made of "lead, Bakelite 'or othe'r 'silitfible material, I but is rhere a'ssumed to' b e maiie of -lead- 'v'ri th an open- "5 ing for win'dow ii) so as to serve not=only'to assist in directing the 'flow "of th'e "heat dissipating 'iiquidflbut also as =a 'shi'eld for the 'X-rays generated. Tube is inimovablyrmounted in the fshell insany'isuitable manner. A-s shown in Fig.

opposite side with hollow tubular extensions F155 3 its'upper eurved surface:is held tightlyagainst the inner surface of the shell wall to the left in Fig. 1 through the annular space between shield I8 and the shell, finally re-entering the other end of shield l8 and again flowing to the right along the outer surface of the X-ray tube I and its anode 2.

As a consequence of the described liquid flow,

the liquid absorbs the heat generated by and within the tube l, and that conducted by the anode 2, and carries and gives it up to the metal of the shell, from the outer surface of which it may be dissipated in any suitable manner, fins, ribs, knobs or other devices (not shown) for increasing the area of exposed heat radiating surface of said shell of course improving efficiency.

Under some circumstances improved cooling effects are secured by the provision of means for dissipating the heat from the shell wall by the use of another fluid.

In the arrangement shown the shell wall is surrounded by a thin metal'jacket 20, made from steel or other suitable material shaped in generally tubular form, with openings where necessary, such as at the window 6. This jacket is closely spaced from the outer surface of the shell, but is rigid with relation thereto. For example, the jacket ends may b provided with short spacing legs 2! separated by Openings for air circulation.

As shown in Figs. 1 and 3, any suitable means is provided for forcibly moving air through the annular space 22 between shell 5 and jacket 20, such as the fan or blower marked generally 23, enclosed within a casing 24 mounted upon the jacket, and in which casing is also enclosed a suitable electric driving motor 24a for the blower, the latter being adapted when operated to receive atmospheric air through the inlet 25 and impel it through the blower outlet 25a into and along the annular cavity 22 toward both open ends of the shell, through which it is discharged to atmosphere.

In operation, therefore. assuming the shell 5 to be filled with oil and the X-ray tube to be in operation, both motors I6 and 24a are started.

During operation all of the heat generated in or by the X-ray tube is absorbed by the circulating oil, which carries it by convection to the wall of the shell 5, from which it is either dissipated directly by radiation or is transmitted to the air current flowing along its outer surface, which by convection carries the heat away to the outside air. a

For simplicity of illustration the circuit wires for th two motors are omitted, but it will be understood that they ar connected to a receptacle 30 to which the usual attachment plug (not shown) may be connected.

In X-ray tubes of this character as heretofore mounted and operated without cooling means, but

with oil within the shell, it has been found that within ten minutes of normal operation the temperature rises to above 500 F., whereas with the present cooling system in operation the temperature does not exceed 200 F. or less and may be maintainedat that value throughout operation of the 'tube over an indefinite period. As a consequence neither the tube nor its mounting parts are subjected to an undesirable temperature and tube operation may be carried on at full capacity for extended periods of time without either injury to th apparatus or discomfort to operator or patient. Other advantages of the invention will be apparent to those skilled in the art.

What I claim is:

1. In combination, a hollow shell provided with a chamber, an X-ray tube mounted in said chamber and spaced from the wall thereof, said shell providing one large liquid-tight chamber adjacent said tube and without external passages, said chamber being filled with a heat conducting electric insulating liquid, an impeller within said chamber for causing motion of said liquid to conduct the heat produced by said tube to the shell wall for dissipation thereby, means mounted on said shell for operating said impeller, a hollow casing enclosing said shell and spaced therefrom to form an annular cavity through which air may flow for absorbing heat from the shell wall and dissipating it by convection, and means mounted on said shell for causing air flow through said cavity.

2. In combination, an elongated hollow shell provided with a chamber, an X-ray tube mounted in said chamber and spaced from the wall thereof to provide an annular elongated space between the walls of the shell and tube, said spac being filled with a heat conducting electric insulating liquid, a tubular guide in said annular space, an impeller mounted in one end of said shell for causing circulation of said liquid through said elongated space in one direction Within and in the other direction outside of said guide, a hollow casing enclosing said shell and spaced therefrom to form an annular cavity through which air may flow for absorbing heat from the shell wall and dissipating it by convection, and means for causing air flow through said cavity.

3. In combination, an elongated hollow shell provided with a chamber, an X-ray tube mounted in said chamber and spaced from the wall thereof to provide an annular elongated space between the walls of the shell and tube, said space being filled with a heat conducting electric insulating liquid, a tubular guide in said annular space, an impeller mounted in one end of said shell for causing circulation of said liquid through said elongated space in one direction within and in the other direction outside of said guide, a hollow casing enclosing said shell and spaced therefrom to form an annular cavity through which air may flow for absorbing heat from the shell wall and dissipating it by convection, and air moving means mounted upon said casing with its outlet communicating with said annular cavity for directing a current of air therethrough.

4. In combination, a hollow heat-conducting shell providing a liquid-tight chamber, an X-ray tube mounted in said chamber and spaced from the wall thereof, said shell providing one large chamber adjacent said tube and without external passages, said chamber being filled with a heat conducting electric insulating liquid, an impeller within said shell and immediately adjacent said tube for causing motion of said liquid to conduct the heat produced by said tube to the shell wall for dissipation thereby, means for operating said impeller, and means for causing a flow of cooling fluid against the external surface of said shell.

hollow heat-conducting shell providing a liquidtight chamber, an X-ray tube mounted in said chamber and spaced from the wall thereof, said shell providing one large chamber adjacent said tube and without external passages, said chamher being filled with'a heat conducting electric insulating liquid, an impeller within said shell and immediately adjacent said tube for causing motion of said liquid to conduct the heat produced by said tube to the shell wall for dissipation thereby, and means for operating said impeller.

EDWARD B. GRAVES.