US2049275A - Shockproof X-ray unit - Google Patents

Description

July 28, 1936.

A. SIMON SHOCKPROOF X-RAY UNIT Filed Aug. 9, 1954 2 Sheets-Sheet l ATTORNEY .July 28, 1936. A. SIMON sHocKPRooF )-RAY UNIT Filed Aug. 9, 1954 2 Sheets-Sheet 2 INVENTOR ALF/:Ep s//uo/v BY /77 ATTORNEY Patented `uly 28, 1936 552 STATES PENT' QFFICE SHOCKPROOF X-RAY UNIT of Delaware Application August 9, 1934, Serial No. 739,081

5 Claims.

My invention relates to X-ray apparatus and particularly to what is known in the art as shookproof units especially those operable for prolonged periods of time as in the administration Vof therapeutical treatment for diseases and industrial radiography.

In order to construct units of this type, which are subjected to relatively high electrical potential during operation, so that the possibility of accidental shocks resulting to an operator or patient are entirely eliminated it has been the usual practice to encase the X-ray tube in a large lead lined drum rendering it ray proof. The high potential energy is supplied to the enclosed tube through suitable insulators provided in the upper portion of the drum which are in turn connected to an overhead system of conductors usually extending through the wall oi the treatment room to an isolated high voltage transformer. All high tension parts are thus positioned out of reach of the normal person lessening the possibility of accidental contact therewith.

However, there nevertheless exists the danger that not only a patient of abnormal height, failing to appreciate the danger, might accidentally contact high voltage carrying parts but also other grounded mechanism, such as treatment tables and the like, may be moved so close to the various conductors as to cause a spark-over with resulting alarm to a patient or disaster to the mechanism. Moreover, the lead lined drums which house the tube are of considerable weight thus rendering it extremely diicult to manipulate the same to the proper position for treating some particular portion of the anatomy.

It has also been proposed to construct a shockproof unit wherein the tube is encased within a grounded metaliic casing with the high tension source of energy having the voltage thereof divided between the electrodes of the tube and of equal potential with respect to ground. The energy is supplied to the tube through exible grounded metallic'cables with the spacing between the electrode terminals of the tube and the grounded metallic casing being suicient to prevent spark-over at operating voltages. Again, however, while the hazard of accidental shocks resulting to a patient or operator are substantially eliminated the overall size of the unit is not reduced and although, by the elimination of a lead lined drum encasing the entire tube, it is reduced in Weight it nevertheless remains diicult of manipulation due to its remaining weight and the size thereof.

In the utilization of such units for the administration of therapeutic treatments or industrial radiography the tube necessarily remains energized for considerable long periods of time and, because of the high potential energy to which it is subjected, operation thereof is accompanied by the generation of considerable heat. In the prior 5 art it has been the usual practice to dissipate this heat to the surrounding atmosphere or in some instances to circulate a cooling and insulating material through the anode.

One of the primary objects of my present invention is the construction of a shockproof X-ray unit adaptable for therapeutical treatment and industrial radiography which eliminates the objectionable features inherent in prior art devices of this type.

Another object of my present invention is the provision of a high tension shockproof X-ray unit of compact size and weight thus increasing the facility of manipulation thereof for treating various portions of the anatomy.

Another object of my present invention is the provision of a shockproof X-ray unit in which the X-ray tube is immersed in a cooling and insulating material within a grounded metallic casing of absolute minimum size and weight, and the X-ray tube is of a foreshortened length for the same applied voltages as when operating in air. Another object of my present invention is the provision of a shockproof X-ray unit of minimum size and weight wherein the X-ray tube is immersed in a cooling and insulating material within a casing and the cooling material is caused to circulate through the anode electrode of the tube and the casing for the purpose of maintaining the tube at an even temperature.

Another object of my invention is the provision of a shockproof X-ray unit operable for prolonged periods of time wherein a tube of foreshortened length is immersed in a cooling and insulating material within a grounded metallic casing of minimum size and weight and the tube may be readily inserted and removed from the casing thus dispensing with the necessity for a skilled mechanic.

A further object of my present invention is the provision of a shockproof X-ray unit adaptable vfor therapeutic treatments and industrial radiography requiring operation thereof for prolonged periods of time wherein a novel circulatory system enables a cooling and insulating material to flow through the anode electrode and the casing surrounding the tube.

Still further objects of my invention will become obvious to those skilled in the art by reference to the accompanying drawings wherein:

Ythis axis, which are welded or otherwise Fig. 4 is a sectional View of a portion oftheV structure of my unit taken on the line IV-IV of Fig. 3,

Fig. 5 is a. sectional View taken on the une v-vof Fig. 1, and Y Fig. 6 is a sectional view of still another portion of my shockproof unit taken on the line l-VI of Fig. 3. Y

Referring now to the drawings in detail ll have shown in the several figures a shockproof X-ray unit in many respects identical to that shown in the copendingapplication of Clayton VT. Ulrey, et al., Serial No. 713,462, filed March 1, 1934, wherein a shockproof unit adaptable for radiographic purposesis shownwand described. The devicecompris'es a Vmetallic casingghaving substantially spherical ends 5 and 6 forming compartments which are joined together by a metallic cylindrical section or passage 1 provided with an X-ray pervious window 8. The configuration of the casing thus conforms substantially tothe potential gradientgbetween the enclosed X-ray tube andthe casing as explained in the above noted pending application.

Each of these spherical ends 5 and 6 is provided with a reinforcing in the form of a metallic ring 9 disposed in a plane parallel with the longitudinal aXisA of the' casing and a similar reinforcing ring I0 disposed at right'angles to rigidly afxed to the respective ends.

' A tubular metallic section I2 is secured `to the spherical end 5 by' any suitable means, such as screws I3 engaging the reinforcing ring 9, and forms an oil tight seal byv the provision of a gasket or the like I4. Similarly a'tubular metallic section I5 extends radially from the spherical end of compartment 55 and may be secured tothe reinforcing ring 9rcarried therebyin the same manner as the section I2. Y

The farY ends of the respective tubular sections I2 and l5 are each provided with a sleeve I6, welded or otherwise affixed thereto, which has a portion thereof of increased diameter threaded internally and externally and forming a pair of annular shoulders or the likeV I'I and I8. An

thereof of 4slightly increased diameter which is e adapted to be held in rm engagement with the shoulder'li, by means of an'annular threaded ring 20, Vengaging the internally threaded portion of the sleeve I6. This ring 20 is screwed in place by a suitable toolinserted in recesses 22 provided therein andV in order to form an oil tight joint a suitable gasket or packing 23 may be interposed between the bushing I9 and the ring 29 which rests upon the shoulder I8.

The lower end of the insulating bushing I9 is provided with a threaded portion of slightly reduced diameter to'which is secured an insulating cap 24 forming an end closure for the bushing I9 with a suitable gasket 25 being provided'to assure anoil tight joint. A. pair of recessed metallic sleeves 26`and121 are provided in the cap 24, as

can beL more readily seen from Fig. 4, each of which has a stud portion 28 protruding below the surface of this cap. Secured to the stud portion 28 of the sleeves 26 and 2l are a pair of cast or pressed metallic terminals 29 and 30 having a substantially rounded contour and free from sharp points and edges. Y Y

Each'of these terminals is provided with an elongatedk slot 32 of suflicient width to allow free` turning of a locknut 33 for securingY the terminals tothe stud portion of the sleeves.V A further pair. of recesses 34' and 35 are Yprovided fin the terminals 29 and 33 which are disposed at right angles to the longitudinal axis of the terminals. Y Y i v Y The tubular section I5 is likewise Yprovided with "an insulating bushing 36 similar to the bushing I9 also provided with a'cap 3l forming an enclosure having a recessed sleeve provided 'with a stud portion 33 identical with the Vportion 28 of the sleeves 26 and 27. An angular metallic strip 39 is secured to this stud portion -38 by means of a locknut l and a set screw 52 is provided in vrthis strip 39 forming a terminal.

lA cylindrical shaped X-ray tube i3 provided;Y

Vterminal ll2'through the intermediary of a flexible lconductor el with the anode end of the tube being supported in a manner to'be hereinafter more fully described. The terminals 29 and 3Q thus constitute the cathode 4terminal [for the X-ray tube, which like the anode terminal 45, all have a substantial radii of curvature and are disposedin sphericalfrelation with reference to the spherical ends and 5, respectively, for the purpose of reducing the electrostatic field concentration thereabout and preventing the formation of corona and sparkover to the casing. f

The X-ray tube 153 is thus disposed in spaced relation to allmetallic parts of the casing with thel envelope substantially concentric with the cylindrical passage 'I and the ends thereof with their respective terminals extending into the compartments formed by the spherical Vends 5 and 6 and coaxially -disposedrrelative to the latter.

The respective recessed sleeves 26 and 2l being of metal lare thus electrically connected to the cathode of the X-ray tube and similarly the recessed sleeve carried lby the cap 3l is electrically connected to the anode of the tube.

In order to energize the X-ray tube a pair of high Ytensioncables i8 and 49, having a metallic sheathing 50, are provided which extend from a suitable high ytension source of electrical energy (not shown) and are connected to the metallic `Contact terminals 54 and 55 v(Fig. 4) areV carried by an insulating member formingtheend closure for the sleeve 52 `and are connected to the conductors of the cables 48 which supplyl the cathode heating current as well as one side of the high potential energy. These terminals protrude beyond-the exterior surface of the insulating sleeve 52 'a -short distance to form studs which engage the recessedmetallic sleeves 26 and 2l in turn electrically connected to the cathode of the X-ray tube. In a similar manner the insulating sleeve surrounding the unsheathed portion of the cable 49 is provided with a projecting stud connectedto the electrical conductor of this cable which likewise engages the recessed sleeve carried by the cap 31 in turn connected to the anode of the X-ray tube. y

The details of construction of the connection of the respective metallic sheathed cables 49 and 5i! 'to the metallic casing are identical so that a description of the connection of cable 4S should be sucient. A clamp 55 formed of two semicylindrical sections secured together by suitable means, such as screws 5l, is adapted to firmly engage the metal sheathing of the cable 48 and the upper extremity of theinsulating sleeve 52. This clamp flares slightly outwardly and is then bent inwardly to form a groove for retaining a metallic ring 58 against the shoulder 53 formed by the reduced diameter portion of the insulating sleeve 52.

An annular collar 59 ts around the lower part of the clamp 56 which threadedly engages the externally threaded portio-n of the ring 2i) thus forcing the ring 58 against the shoulder 53 and the insulating sleeve 52 inwardly of the tubular section i2 so that the contact terminals 54 and are maintained in slidable engagement with the recessed sleeves 2 5 and 2.

In order to reduce the insulation requirements between the high voltage terminals of the X-ray tube and the grounded metallic casing it is customary to ground the midpoint of the transformer serving as the high voltage Source thus necessitating insulation requirements between the terminals of the tube and the metallic casing equal to one-half that of the high potential source to ground. Moreover, to still further reduce the insulation requirements below that normally Vrequired at the same applied voltage for the tube when operating in air, the metallic casing is lled with an insulating and cooling material, such as oil completely immersing the X-ray tube 43 and surrounding the insulating bushings I9 and 3S thus augmenting the insulating characteristics between the unsheathed portions of the cables 4c and 49 and the-metallic sections I2 and i5 of the casing'. The connection of the insulating bushings I9 and 35 to the casing as well as the high tension cables 48 and 49 accordingly forms an oil tight seal enabling the casing to be moved to any desired position without leakage.

During operation of the tube for prolonged periods of time, such as in the administration of therapeutical treatments and industrial radiography, considerable heat is generated which is dissipated to the cooling and insulating material causing an expansion thereof and necessitating vthe provision of some compensating means.

f However, in my present structure I eliminate the necessity fortheprovision of expansion compensating means by maintaining the operation of the tube at a much lower temperature'and enabling a circulation of the cooling and insulating means through the hollow anode stem of the X-ray tube and the casing.

To this end the anode of the X-ray tube may be constructed in the manner shown and claimed in the copending application of D. Gordon Sharp, Serial No. 735,181, filed July 14th, 1934, wherein an inlet conduit 62 is provided for the ingress of the oil 6E) and after circulating through the anode in the vicinity of greatest heat it discharges through the hollow anode stem, which forms an outlet conduit'63 concentrically disposed relative to the inlet conduit, into the casing as shown by the arrows in Fig. 3. Before insertion of the tube in the casing the inlet conduit 62 is screwed into the hollow anode stem and a disc of insulation material 64' is then screwed into the inlet conduit 62 and fastened in place by suitable means, such as a locknut 65.

The insulated disc 64 is provided with a longitudinal passage B6 which communicates with the inlet conduit 62 and a suitable bushing 67 threadedly engages the disc 64 in alignment with the passage BS for connection to an intake line from a reservoir or the like, housing the cooling and insulating material. The flexible conductor 4l is first connected to the strip 39 by the set screw 42 and the X-ray tube slid into the casing with the cathode terminals slidably engaging the recesses 34 and 35. The insulating disc 64 is then secured to the reinforcing ring I0 carried by the casing in an oil tight manner by the provision of suitable fastening means, such as screws 68 and gasket 69 and when in place cooperates with the inlet conduit 62 in forming a support for the anode end ofthe tube 43.

The opposite end or compartment 5 is likewise provided with an insulating disc 'I0 secured thereto by suitable means, such as screws l2 and a gasket 13 is provided for rendering the connection oil tight in the same manner as the disc 64. lA passage 'I4 communicates with the interior of the casing and a bushing 15, which is adapted to be connected to the return line leading to the oil reservoir, threadedly engages this disc 'l and, like the bushing 61, has a male portion engageable with a female portion surrounding the return line to form an oil tight connection. In order to make the entire unit X-ray proof except at the ray pervious window 8 a layer of metaly 15 of high atomic weight, such as lead, covers the entire casing forming an integral part thereof except at the connection of the discs 64 and 10. However, end caps 11 formed of the same material as the layer 16 are detachably connected to the insulating discs by suitable fastening means, such as screws 'i8 to enable detachment thereof and of the discs 64 and 'iii for insertion and removal of the X-ray tube 43.

The cylindrical passage portion l of the casing may be provided with reinforced portions i9 and 88, as seen more clearly in Figs. 3 and 5, to which suitable handles (not shown) may be secured for moving the entire unit to various angular positions in its support to align the pervious window with the particular portion of a patient it is desired to treat. Moreover, this window 8 is not only perivous to X-rays but also to visible light in order that an operator may readily determine when the cathode electrode 45 is incandesced.

During operation of the tube the cooling and insulating material flows from the reservoir through the inlet line, the passage 66 in the disc 64, and inlet conduit 62 to the anode where it contacts the portions thereof of greatest heat.

'vection currents dissipate some of the heat through the walls of the casing to the surrounding atmosphere.Y Furthermore, the cooling and insulating material within theV casing being in l circulatory relationship with the anode cooling system enabling the same to flow into 'the reservoir thus dispenses with the necessity for the provision of. expansion bellows or other compensating means for increases inV volume of the material upon a rise in temperature. l

It thus becomes obvious to those skilled in the art that I have provided a shockproof X-ray unit of minimum size and weight thus increasing the facility of manipulation thereofin the administration of therapeutical treatments and industrialV radiography. The X-ray tubeis made of foreshortened length for the same applied voltage as when operating in air, dueto the utilization of a cooling and insulating material of high dielectric strength, and the casing has a contour conforming to the electrical field distribution or potential gradient from the tube to the surrounding casing thus enabling a minimum spacing thereof determinable'by the dielectric strength of the insulating material.

This accordingly permits not only the casing to be of minimum sizeand weight but the entire volume of insulating and cooling material required witnin the casing is considerably reduced which still further reduces the weight ofthe unit.

Moreover, a circulatory system of high eniciency is provided for cooling of the tube during operation for prolonged periods of time byk causing the cooling and insulating material to circulate from a `reservoir in series relationship through the anode cf the tube and then through the casing priory to its return to the reservoirfor final cooling. l Y Q Although I have shown one specic embodiment .of my invention I do not desire to be limited thereto as variousother modifications of the same may be made without departing from the spirit 1. A shockproof X-ray unit comprising a kgrounded metallicX-ray opaque casing having substantially spherical ends connected by a tubular passage, an X-ray tube concentrically disposed within said casing having a cathode and an anode which becomes heated during operation, a body of cooling and insulating material in said casing and immersing said X-ray tube, an inlet duct formingv a support for the anode end of said tube and having a passage extending from theanode of said tube and communieating with a reservoir for the ingress ofthe cooling and insulating material, an outlet duct formed in said anode and extending therefrom to said casing for discharging said material'into said casing to immerse said X-ray tube after circulation of said-material .through saidv anode, and a closure. member for onefend of said casing provided with a passage communicating with said casing and the reservoir to complete a circulatory system for the purpose of cooling said tube during operation. Y

2. A shockproof X-ray unit Vcomprising a grounded metallic X-ray opaque casingV provided with Van X-ray and light pervious window and 5 having substantially spherical ends Yconnected by a. tubular passage, an X-ray tube concentrically disposed Within said casing provided withY a, cathode and an anode which becomesA heated during operation and having electrode terminals 10,

of substantial radii of curvature spherically disposed with reference to the spherical ends of said casing to reduce the electrostatic eld concentration therebetween, a body of cooling and insulating material in said casing andV immersing said X-ray tube, means connected to the anode of said X-ray tube and to said casingfor caus ing said cooling Vand insulating material to flow through said anode and said-.casing in circula- Y toryr relationship to cool said' tube during operation, flexible grounded metallic cables 'adaptedl to supply high-tension electrical energy to said tube for causing energization thereof, and means for connecting said cables to said casing and toV the electrode terminals of said tube to form an i5 oil tight seal therebetween. Y

3. A shockprooi X-ray unit comprising a grounded metallic X-ray opaque casing provided with an X-ray and lightpervious window and having substantially spherical ends connected by 30 a tubular passage, an X-ray tube concentrically l disposed within said casing provided with a cathode and an anode which becomes heated during operation and having electrode terminals of substantial radii of curvature spherically disposed 35 with reference to the spherical ends of said casing to reduce the electrostatic field concentration therebetween, a body of cooling and insulating material in said casing and immersing said X-ray tube, an inlet duct 'forming a support for the anode end Yof said tuberand having a Vpassage extending from the anode of said tube and communicating with a reservoir for the'ingress vof theV cooling and insulating material, Yan outlet duct formedin said anode and extending therefrom to said casing for discharging said material into said casing to immerse said X-ray tube'after circulation of'said material through said anode, a closure member for one end Yoffsaid casing provided with a'passage communicating with said casing andthe reservoir tocomplete a circulatory system for the purposeof cooling Ysaid'turbe Y during operation, flexible groundedmetallic cables adapted to supply high potential electrical energy to said tube for causing energization thereof, and means for connecting said cables-to said casing and to the electrode terminals of said tube and forming'an oil tight seal therebetween.

4. A Vshockproof X-ray unit comprisingV a grounded metallic X-ray opaque casing having 60 substantially spherical endsconnected Vby a tubular passage,an X-ray tube concentrically disposed within said casing having a cathode and an anode which becomes heated during operation, a body of cooling and insulating material in said casing and immersing said X-ray tube, detachable closure means at each end of'said casing forming an oil tight seal therewith,` one of said closure means being connected` to said anode and forming a support for the anode end of said 70 tube and provided with a passage communicatingV with the anode and a reservoir to enable the ingress ofV the cooling and insulating material,Y and the remaining closure means being also provided with a passage communicatingV with said 75 casing and the reservoir to enable the egress of said cooling and insulating material after circulation thereof through the anode of said tube and said casing.

5. A shockproof X-ray unit comprising a grounded metallic X-ray opaque casing having substantially spherical ends connected by a tubular passage, an X-ray tube concentrically disposed Within said casing having a cathode and an anode which becomes heated during operation, a body of cooling and insulating material in said casing and immersing said X-ray tube, a detachable closure means secured to said casing and forming an oil tight seal therewith for the purpose of enabling the insertion and removal of said tube comprising a disc of insulating material provided with a passage therein having one end thereof communicating with a reservoir, an inlet duct connected to the anode of said X-ray tube and to said disc for supporting one end of said tube, and communicating with the passage provided in said disc to enable the ingress of oil to said anode, and means forming a discharge return path to the reservoir for the egress of said cooling and insulating material including the interior of said casing.

ALFRED SIMON.

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