US2280711A - High tension apparatus - Google Patents

Description

April 21, 1942. R. R. MACHLETT ETAL HIGH TENSION APPARATUS Filed April 25, 1941 Patented Apr-.21, 1942 2,880,711 man TINSION APPARATUS Raymond I. New Canaan. and Joseph W.8kehan,8 ord,0o m meamsmmmogi'nuasm dale, com, a corporation h.

April 15, 1041, Serial No. 390,310

Gains.

- This invention relates to high tension electrical apparatus and is concerned more particularly with a novel detachablecoupling which may be employed for a wide variety purposes in mak- -ing connections in shockproo! high tension sys tems. The new coupling may be advantageously used in systems of numerous kinds, but since it aflords special advantage in the x-ray iield, an adaptation oi the invention suitable for use with x-ray apparatus will be illustrated and described in detail for purposes of explanation.

In modern shockprooi X-ray equipment, the

' tube is usually mounted in a metallic housing filled with an insulating. liquid, such as oil, and high tension energy is supplied to the tube from a source, such as a transformer, through heavily insulated cables provided with a metallic sheathing which is grounded and serves to ground the housing. The cables are preferably detachable from the housing and various forms of detachable connections may be employed for the purpose. Heretoi'pre, the connection employed commonly included a sleeve of rigid insulating material, such as porcelain or that known commercially in Bakelite," mounted on and enclosing one end of the cable, and a socket of similar insulating material mounted on or within the housing. The sleeve and socket were provided with terminals connected, respectively, to the cable conductor and the tube terminal and, to establish a connection from the tube to the source through the cable, the sleeve was inserted in the socket to bring the sleeve and socket terminals into contact, after which, the sleeve was secured in place by suitable clamping means.

In such an installation, the tube is, insulated by the liquid in which it is immersed and the conductors within the cables are insulated by solid insulating material. Each sleeve and its socket are made to flt snugly, but commercially cannot bemade with a suillciently tight at to exclude all air between them. The contacting terminals oi the sleeve and socket are, therefore, insulated by air only in the space between the opposed suriaces oi. the sleeve and socket, and this air insulation is the weak spot in the system.

X-ray apparatus frequently operates at voltages of atleast 50 PKV between the terminals and ground and, since the tube housing is grounded through the grounded metallic sheathing on the cables, the air path between the socket and sleeve from the terminals to the grounded housing must be very long in order to prevent sparkover. This requires that the sleeve and socket be long and usually necessitates the provision of long necks onthehousingtoenclosethesockets. Thepracticallimitationsaresuchthatthesleeveand socket combination ordinarily has a breakdown voltage under normal atmospheric conditions which is not greatly in excess of the, voltage ratingoithetubeandtheuseoft'heairinsulation, therefore, represents a potential hazard.

when x-ray equipment having detachable cable connections of the type above described and now in common use is employed at high altitudes, the breakdown voltage 0! the connections is reduced and a similar eflect results from excess humidity in the atmosphere. A flashover for any reason not only destroys the insulating members of the connection but may also produce other serious results, as, for example, if the equipment, as is frequently the case, is used in operating roomswhere ether vapor' may be present, a breakdown my ignite iumes.

Another disadvantage of the air insulated connections is that the high potential gradient causes the air therein to become ionized with resultant corona elects. These eitects not only give rise to high-frequency oscillations in the circuit involving the cable capacitance, which reduce the life of the cable, but also result in the formation of nitrous oxide, which is likely to cause injury to the cable insulation and. also tends to corrode the contacting terminals and may result in suiliciently poor contact to detrimentally elect the filament circuit.

Another practical difliculty encountered in the construction of the terminals above described is that the sleeve, which is mounted on the cable, cannot be made to fit the latter in such a way as to exclude air. Also, it is necessary to provide insulation within the sleeve for the connection between the conductors in the cable and the sleeve terminals. The upper end of the sleeve is ordinarily received within a metallic bell-shaped element, known as a stress flare, which is electrically connected to the metallic sheathing on the cable and, in the assembled equipment, is also connected electrically to the metallic housing of the tube. The spaces within the sleeve around the cable and between the cable and the flare must, accordingly, be filled with insulation and, for this purpose, an insulating compound capable ot withstanding high operating temperatures is used. As the compound must be introduced into the spaces between the cable and the sleeve and flare while it is heated to a high temperature, it is extremely dimcult to fill those spaces with the hot compound in such a way as to prevent the formation of air holes and, it such air holes are present, breakdown is likely to occur.

The present invention is, accordingly, directed to the provision of a novel detachable coupling for use in shockproof high tension electrical equipment, such as X-ray apparatus, which does not involve the use of air as an insulator, is of long life, and can be constructed and used with facility. The new coupling comprises a pair of interfltting parts, such as a sleeve and a socket,

and one of the parts is made preferably of rigid insulating material and the other of yielding insulating material. The parts are provided with terminals which are engaged when one part is fully inserted into the other and in fltting the parts together, the surface of the yielding part conforms to that of the rigid part and there is complete contact of the parts over their opposed surfaces. I

When the coupling is used, for example, in X- ray apparatus for connecting a cable to a shockproof tube'immersed in oil within a housing, the rigid part may be a socket mounted within the housing withits terminal connected to the terminal of the tube. The yielding part then takes the form of a sleeve mounted on the end of the cable and is preferably so applied thereto as to be united to the insulation thereon. The terminal of the yielding sleeve is connected to a conductor within the cable and when the yielding sleeve is inserted in therigid'socket, the two are forced together by suitable clamping means, so that the opposed surfaces of the sleeve and socket are forced into and maintained in contact and there is no air serving as insulation between them.

The rigid part of the new coupling may be made of various insulating materials, such as porcelain, or any suitable synthetic material, such as that known as Bakelite," and the yielding part may be made of a suitable synthetic rubbery material, such as that known commercially as "Neoprene." Inthe application of the yielding part to the cable, the latter is preferably provided with the usual stress cone and the rubbery material is subjected to heat and pressure and molded in position, so that the material flows and fills the entire space within the cone. Since a connection made with the new coupling contains no air, difllculties arising from corona and sparkover are avoided and the coupling members may be made shorter and more compact than those previously used for the purpose.

For a better understanding of the invention, reference may be had to the accompanying drawing in which Fig. 1 is a view, partly in section and partly in elevation, with parts broken away, illustrating one form of the new coupling employed in a shockproof X-ray apparatus;

Fig. 2 is a view, partly in section and partly in elevation, through one of the parts of the coupling applied to a cable;

Figs. 3 and 4 are sectional views illustrating modified forms of one 'end of the part of the coupling applied to the cable; and

Fig. 5 is a view in side elevation illustrating the use of the new coupling as a cable termination with a shockproof X-ray unit.

The drawing illustrates the use of the coupling as a cable termination on cables for supplying current to an X-ray apparatus which includes a housing Ill containing a tube II and provided with a pair of necks I2, in each of which is made of any suitable material, such as porcelain or that known commercially as Bakelite." The socket, which forms one of the interfltting parts of the coupling, has a circumferential flange H at its open end and it is mounted within its neck i2 with its flange resting upon a gasket I! lying on a shoulder formed around the opening into the neck. The inner wall of the opening is threaded and the socket is held in place by a ring I which is screwed into the opening and compresses the flange it against gasket I 5. This makes an oil-tight seal between the socket and the innerwall of the neck, so that escape of the insulating fluid within which the tube H is immersed within the housing is prevented.

Embedded in the socket at its lower end are one or more terminals II which are connected mounted a socket insulator II, which may be to the terminals at one end of the tube. In the apparatus shown in Fig. 5, the socket Ila has two terminals connected by leads II to terminals at one end of the tube, while the socket I3b has a single terminal connected by a lead- I! to the terminal at the other end of the tube. The inner ends of the terminals H are exposed within the socket and each terminal has a recess in its inner end.

High tension energy is supplied to the tube through a cable 20, which includes one or more conductors. in the construction shown in Fig. 2, the cable contains two conductors (not shown) which extend concentrically. through the cable and the conductors are contained within a body of insulation which is enclosed within a wrapping 2-I of tape. overlying the tape is a metallic sheathing 22 and over the sheathing is a decorative'outer layer (not shown) which may be of silk or the like.

The free end of the cable is encased within a sleeve 23, which forms the other of the interfltting parts of the new coupling and is made of a corona-resistant rubbery compound, which is preferably a synthetic .rubber, such as that commercially known as Neoprene." Before applying the sleeve to the cable, the metallic sheathing 22 and the tape 2| are removed for a considerable distance back from the end and the surface of the rubber insulation on the cable is cleaned. The sleeve'is provided with a circumferential flange 24, which is of greater diameter than the opening into the neck l2, and, above the flange, the cable carries a stress flare 25, which is made of metal and has its small end connected to the end of the metallic sheathing 22. For this purpose, the small end of the flare is inserted beneath the sheathing, a wire wrapping 26 is applied, and the parts are then soldered together. The large end of the flare terminates in a cylindrical flange 21 and the sleeveis so formed as to fit within the flange and fill the space between the interior of the flare and the outer surface of the cable. The

,provision of solid insulation filling this entire space is of extreme importance and, with the previous constructions, it was difllcult to introduce the hot insulating compound within the flare in such manner as to avoid the presence of air holes. No such difficulty is encountered when the space is filled by a portion of the sleeve. The flange 24 projects outward past the free edge of flange 21, as shown.

At the closed end of the sleeve, a disc 28 of rigid insulating material is embedded in the material of the sleeve and mounted within the disc are one or more terminals 29 having split ends a,sso,ni v.3 tl-whichproiecttbrmbtbeandofthssleeva. insulstionandbymoldingthsmbberymaterial 'rhoterminalsllaretothecondueton -.undarheatandpnsgure.as theeliminthecablebyieabtlwhichareunbeddedin ofairfromwithintheflareisrelatively materhlthu-insulatestheleadsandterminals 6 Afterthemoldingoperationdescribedhasbeen and'holdsthemnl'operlsinpolition. completedtheassemblyissublectedtoacm'ing .Intheuseofthenewcoupling,thesleeve23 operationoftheusualtype. Thesleeve'portion isinsertedwithinthesocketitwithtbeprolectofthecouplingisthenreadyforuse. ingportions Ilofthe'sleeveterminalsl. enter- In the foregoing. the new coupling hasbeen ingtherecessesinthesocketterminalsll. The 10 describedintheformofacableterminationemlower'face of the-flange! ofthe sleeve ployed for connecting a cable to a tube within restsontheuwerendotthenecklland overlies m lmwe ltwiil amr a theupperfaceofringil.-'withthepartsin thecolmlinsm y 'lybeemployedasa this position. a bell-shaped clamping member 33 termination for connecting the cables to the anditslockimring, which have previously transformeranditmayalsobeusedinamodibeen slipped on thecahle, are moved down until fled form for connecting together two lengths of member it rests upon the upper surface or the 7 cable for connecting a switch in the high voltflarell. Theringfl,whichisinternallvthmdage circuittoeitherthetube orthetransiormer. 0d,!lthenscre'ddontheendoftheneckand Variousotheruses-forthecouplingwillbereadturned down until the force thereby applied to i1! app ren In all .forms. the rminal thesleeve Ncausesthematerial thereoftobe through whichthehigh en n er y of the socket i3 and flare II.

Instead ofmountingtheterminais 20in adisc It, which is thereafterembedded in the end of the sleeve,-the disc maybe omitted and the terminals 34 embedded'in the sleeve material. The terminals are connected as before by leads II to the cable conductors. The terminals have the split ends 8' receivable in, the recesses in the socket terminals-i1.

In another modlfled form illustrated in Fig. 4, terminals 81- are mounted. in a disc 38, which may be of rigid insulating material, the disc having a diameter substantially the same as the outer dtameterof sleeve 2i. The disc is amxed to the end-of the-sleeve and the terminals are connected to the cable conductors by leads 3! which pass through the body of the sleeve ma- The sleeve may be formed and applied to the end of the cable in various ways, as, for example, by molding. In this operation, the cable is stripped of the metallic sheathing and-tape back from its free end, the flare is applied, and the sleeve terminals are connected by their leads to the cable conductors, the terminals being mounted in discs of insulation or not, as may be desired. Thereafter, the rubbery material, which has been roughlyshaped to the desired form, is applied to the surface of the cable and inserted within the flare. The material is also applied over the proper portions of the sleeve terminals and their leads, cement being preferably applied previously to the metal parts, such as the terminals and leads and the internal surfaces of the flare.

The assembly is then placed in a mold and heat and pressure are applied until the rubbery material is softened and rendered fluent, so that it not only adheres to the previously cleaned surface of the insulation and the metal parts but also flows into and completely fllls the space within the flare. The result is that the sleeve is united to the insulation and the metal parts and, as it flows into the flare, it forces out the air between the latter and the cable. As previously pointed out, it is of utmost importance that no air be present between the flare and the cable a without air employed are completely insulated by solid insulation and there is no air present in the coupling, so that 1 by the use of the new coupling, a high tension system may be rendered completely shockproof as an insulator at any p i P We claim:

1. A detachable coupling for use in high tension apparatus which comprises a socket of rigid insulating material, a terminal mounted in the wall of the socket and exposed within the latter, a sleeve of yielding insulating material having a closed end, said sleeve being receivable within the socket with the opposed surfaces of the socket and sleeve lying in full contact with no air between, a terminal embedded in the closed end of the sleeve in position to engage the socket terminal when the sleeve is fully inserted into the socket, and means for holding the sleeve within the socket and applying force to the sleeve to cause the opposed surfaces of the sleeve and socket to make'full contact.

2. In high tension apparatus, such as X-ray equipment, which includes a housing containing a device to be supplied with high tension en-- ergy, the combination of a socket of rigid insulating material adapted to be mounted in an opening in the wall of the housing and having at least one terminal mounted in its wall and having portions exposed both inside and outside the socket wall, a high tension cable containing at least one conductor, said cable being provided with a layer of insulating material enclosing the conductor, a sleeve of yielding insulating material enclosing the end of the cable and adhering to the insulation thereon, at least one terminal mounted at the end of the sleeve connected to the conductor within the cable, the sleeve being shaped to permit its insertion into the socket to bring the terminals into contact and to force the opposed surfaces of the sleeve and socket into tight contact, and a grounded flare enclosing the end of the sleeve remote from the terminal.

3. In high tension apparatus, such as X-ray equipment, which includes a housing containing a device to be supplied with high tension energy,

,the combination of a socket of insulating material adapted to be mounted in an opening in the wall of the housing and having at least one terminal mounted in its wall, the terminal having portions exposed both inside. and outside said socket wall, a high tension cable containing at least one conductor, said cable being provided with a layer of insulating material enclosingthe conductor and a metallic wrapping over the insulating material and stopping short of the end of the cable, a flare mounted on and the sleeve terminal and lying within the body of the sleeve material, the sleeve being adapted to be inserted into the socket with the outer surface of the sleeve in tight contact with the inner surface of the socket and the sleeve terminal in electrical contact with the socket terminal.

4. In high tension apparatus, such as X -ray equipment, which includes a housing containing a device to be supplied with high tension energy, the combination of a socket of insulating material adapted to be mounted'in an opening in thewall of the housing and having at least one terminal mounted in its wall, the terminal having portions exposed both inside and outside said socket wall, a high tension cable containing at least one conductor, said cable being provided with a layer of insulating material enclosing the conductor, a grounded flare of V trical contact.

'6. In high tension apparatus, such as x-ray equipment, which includes a housing and a de- .vice within the housing to be supplied with high tension energy, the combination of a socket of insulating material mounted 'in an opening in the wall of the housing and having at least one terminal mounted in its wall, a connection within the housing between the socket terminal and a terminal of the device, a cable connected at one end toasource of energy, a sleeve of yield ing insulating material having a cloud end, said sleeve enclosing and adhering to the end of the cable and provided with at least one terminal embedded in the closed end of the sleeve and connected to a conductor within the cable, the sleeve being mounted, in the socket with the sleeve and socket terminals in contact, and means engaging a portion of the housing and operable on a portion of the sleeve to cause the sleeve to make tight contact with the entire inner surface of the socket.

7. In high tension apparatus, such as X-ray :5 equipment, which includes a housing and a device mounted on the cableremote from the end, a

sleeve of yielding insulating material enclosing the end of the cable and adhering to the insulation thereon, said sleeve having a portion extending into and making tight contact with the interior of the flare, a disc of insulating material mounted on and closing the free end of the sleeve, at least one terminal mounted in the disc and having portions exposed on opposite sides of the disc, and a connection between.

, ing material adapted to be mounted in an opening in the wall of the housing and having at least one terminal mounted in its wall, the terminal having portions exposed both inside and outside said socket wall, a high tension cable containing at least one conductor, said cable being provided with a layer of insulating material enclosing the conductor, a grounded flare mounted on the cable remote from the end, a sleeve of yielding insulating material enclosing the end of the cable and adhering to the insulation thereon, said sleeve having a portion extending into and making tight contact with the interior of the flare, a disc of insulating material embedded in the sleeve material at the free end of the sleeve, at least one terminal mounted in the disc and having portions exposed on opposite faces of said disc, and a connection between the conductor and the disc terminal and lying within the body of the sleeve material, the sleeve being adapted to be inserted into the socket with the outer surface of the sleeve in tight contact with the inner surface within the housing to be supplied with high tension energy, the combination of a socket of insulating material mounted in an opening in the wall of the housing and having at least one terminal mounted in its wall, a connection within the housing between the socket terminal and a terminal of the device, a cable connected at one end to a source of energy and containing at least one conductor, said cable being provided with a layer of insulating material enclosing the conductor, a grounded flare mounted on the cable remote from the end, a sleeve of yielding insulatin: material enclosing the end of the cable and adhering to the insulation thereon, said sleeve having a portion completely fllling the space within the flare around the cable, and at least one terminal mounted in the sleeve and having a portion exposed outside said sleeve, a connection between theconductor and the sleeve terminal and lying within the body of the sleeve material, the sleeve being mounted in the socket with the terminals in contact, and means for applying force to the sleeve to cause it to make contact with the entire inner surface of the socket.

8. In high tension apparatus, such as X-ray equipment, which includes a housing and a device within the housing to be supplied with high tension energy. the combination of a socket of in- I sulating material mounted in an opening in the wall of the housing and having at least one terminal mounted in its wall, a connection within the housing between the socket terminal and a terminal of the device, a cable connected at one end to a source of energy, a grounded flare encircling the cable near the other end thereof, a sleeve of yielding insulating material enclosing and adhering to the end of the cable and having a circumferential flange overlying the end of the socket and having a portion filling the space around the cable within the flare, at least one terminal mounted in the sleeve and having a portion exposed outside said sleeve, a connection between the conductor and the sleeve terminal and lying within the body of the sleeve material, the sleeve lying within the socket with the terminals in contact, and means engageable with the flare and operable to app y force to the sleeve to cause it to make tight contact with the entire inner surface of the socket.

9. In high tension apparatus, such as X-ray t and the two terminals in elec equipment, which includes a housing and a device within the housing to be supplied with high tension energy, the combination of a socket of insulating material mounted in an opening in the wall of the housing and having at least one terminal mounted in its wall, a connection within the housing between the socket terminal and a terminal of the device, a cable connected at one end to a source of energy, a grounded metallic flare encircling the cable near the other end thereof, a sleeve of yielding insulating material enclosing and adhering to the endof the cable and having a circumferential flange overlying the end of the socket and having a portion filling the space around the cable within the flare, at least one terminal mounted in the sleeve and having a portion exposed outside said sleeve. a connection between the conductor and the sleeve terminal and lying within the body of the sleeve material, the sleeve lying within the socket with the terminals in contact, a clamping collar outside the flare, and means engaging the housing and collar and operable to apply force to the sleeve to cause it to make tight contact with the entire inner surface of the socket.

10. In high tension apparatus, a cable which includes a conductor enclosed within a layer of a rubber compound acting as insulation, a sleeve of yielding insulating material mounted to enclose one end of the cable, the sleeve adhering to the surface of the layer,'a grounded flare encircling the cable, said sleeve extending into and making tight contact with the interior of the flare, and a terminal mounted in the end of the sleeve and connected within the sleeve material to the conductor in the cable.

11. In high tension apparatus, a cable which includes a conductor enclosed within a layer of a rubber compound acting as insulation, a sleeve of yielding insulating material mounted to enclose one end of the cable, the sleeve adhering to the surface 01 the layer, a terminal mounted in the end of the sleeve and connected within the sleeve material to the conductor in the cable, and a grounded metallic flare mounted on the cable, the sleeve having a portion completely filling the space within the flare between the latter and the surface of the cable.

12. A detachable coupling for use on high tension apparatus which comprises an elongated socket of rigid insulating material having a circumferential flange around its open end and having at least one terminal mounted in its closed end, a high tension cable containing at least one conductor, said cable having a layer of insulating material enclosing the conductor, a sleeve of yielding insulating material having a closed end and enclosing the end of the cable and adhering to the outer surface of said layer of insulating material, said sleeve having a circumferential,

flange remotefrom the end of the cable, at least one terminal mounted in the closed end of the sleeve and connected to the conductor, said sleeve terminal being engageable with the socket terminal when the sleeve is inserted in the socket, and means for clamping the sleeve and socket flanges together to hold the sleeve securely in the socket with their respective terminals in engagement.

13. A detachable coupling for use on high tension apparatus which comprises an elongated socket of rigid insulating material having at least one terminal mounted in its closed end, a high tension cable containing at least one conductor, said cable having a layer of insulating material enclosing the conductor, a sleeve of yielding insulating material having a closed end and enclosing the end of the cable and adhering to the outer surface of said layer of insulating material, a grounded metallic flare encircling the sleeve at a place remote from its closed end, the sleeve making tight contact with the interior of the flare, and at least one terminal mounted in the closed end of the sleeve and connected to the conductor, said sleeve terminal being engageable with the socket terminal when the sleeve is inserted in the socket.

14. A detachable coupling for use on high tension apparatus which comprises an elongated socket of rigid insulating material having a cir'-- cumferential flange around its open end and hav ing at least one terminal mounted in its closed end, a high tension cable containing at least one conductor, said cable having a layer of insulating material enclosing the conductor, a sleeve of yielding insulating material having a closed end and enclosing the end of the cable and adhering to the outer surface of said layer of insulating material, said sleeve having a circumferential flange remote from the end of the cable, a

grounded metallic flare encircling the sleeve adjacent the flange, the sleeve making tight contact with the interior of the flare, at least one terminal mounted in the closed end of the sleeve and connected to the conductor, said sleeve terminal being engageable with the socket terminal when the sleeve is inserted in the socket, and means for clamping the sleeve and socket flanges together to hold the sleeve securely in the socket with their respective terminals in engagement. RAYMOND R. MACI-ILE'I'I. JOSEPH W. S HAN-

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