US2444687A - Periodic circuit breaker with a liquid conductor particularly for contact current changers - Google Patents

Description

y 1948- M. H. w. WIDAKQWICH 2,

PERIODIC CIRCUIT BREAKER WITH A LIQUID CONDUCTOR, PARTICULARLY FOR CONTACT CURRENT CHARGERS Filed April 6, 1945 luvaNw-oa M.H. \N.W iDAKuwicH Patented July 6, 1948 PERIODIC CIRCUIT BREAKER WITH A LIQ- UID CONDUCTOR PARTICULARLY -FOR CONTACT CURRENT CHANGERS Marius Hugo Wilhelm Widakowlch, Stocksund, Sweden Application April 6, 1945, Serial No. 588,914 In Sweden April 6, 1944 5 Claims. (Cl. 20032) The present invention relates to a periodic circuit breaker which is particularly intended to be used as a contact current changer for the conversion of alternating current into direct current, or vice versa, and wherein an electrically conducting liquid, preferably mercury, is employed as a conductor, while contact members are used for periodic closing and breaking of one or more circuits. The invention refers particularly to such circuit breakersof said type which consist of two receptacles holding the contact liquid and communicating with each other, said receptacles being arranged concentrically within one another, and 'one of which is stationary and the other rotatably mounted, the' contact liquid being adapted to circulate through the receptacles in a manner to form a number of jets ejected from the one receptacle, said jets cooperating with peripheral contacts in the other receptacle. The invention is principally distinguished by the feature that the rotary receptacle is formed as a rotary pump, preferably as a centrifugal pump, to circulate the contact liquid through the two receptacles. By this means a compact constructionoi the circuit breaker is obtained, inasmuch as the circulation pump, which is otherwise necessary, is now dispensed with. Thearrangement also involves the advantage that the circulation system may be housed,-together. with all of the contacts, within a closed vessel which is preferably constituted by the one receptacle, which is then preferably arranged to be stationary, whereas the other receptacle is rotatably mounted within said first-mentioned receptacle and adapted to be driven from an external source of power by means of a rotating magnetic field. .If desired, the outer vessel may then be hermetically closed, and the circuit breaker may be adapted to operate in, vacuum or in an atmosphere .ot a neutral gas sothat the contact breaking takes place without sparking, as far as possible.

The invention will be explained more closely with reference to the accompanying drawing,

2 drical portion 3 and a bottom portion provided with a downwardly extended central portion 4 and a draining hole closed by means of a threaded stopper 5. The two receptacles communicate with one another through a central hole i in the lower portion of the inner receptacle 2. The receptacles are filled with mercury which. when the apparatus is inoperative, takes about the level indicated by the dashed line I. The inner receptacle is mounted by means of ball bearings 8, 9 on a central journal pin l0 screwed fast into a cover I I of glass or other non-magnetic and electrically non-conducting material. The cover It is rigidly connected with the receptacle I and tightens against a flange l2 extending around the upper edge thereof. The ball bearings 8, l are enclosed within a cap I: for'ming'a cylindrical extension of a cover 14 covering the upper part of the inner receptacle while being rigidly united with the receptacle. The latter cover consists of magnetic material, preferably iron, and is provided with a number of pole pieces ii, the upper surfaces of which are located immediately underneath the cover I I. Rigidly arranged on a journal I6 coaxial with the pin l0 and situated above the cover H is a yoke I! of iron, said yoke supporting a number of magnet cores corresponding to the pole pieces l5, said cores being provided with magnet windings IS. The parts M, l5, l1 and-l8 thus form a magnetic circuit through which the torque of the motor may be transmitted to the inner receptacle 2, which then rotates at the speed of the motor shaft. The pole pieces are surrounded by rings 20 of copper or other electrically conducting material said rings "being adapted in known manner to facilitate-the starting.

The inner receptacle 2, is of a downwardly tapering, substantially conical shape, and is provided on the inside thereof with a number of radially disposed partitions Zl adapted at therotation to entrain the quantity of mercury" flowing through the receptacle, the rotating receptacle then acting as a centrifugal'pump, and the mercury entering from the outer receptacle to the inner one through the opening, 6. In order to increase the impelling force acting upon the mercury, the lower parts of the radial partitions 2| mercury will thus flow up along the wall of the receptacle throughthe action of the centrifugal force, a portion of the mercury then escaping through a number of apertures 22 provided in the wall, said apertures opening into ejecting nozzles 23. To ensure the discharge of a sumcient quantity of mercury through said nozzles. the receptacle is provided on the inside thereof with a pro- Jecting circularly extending edge 23 adapted to catch a portion or the mercury. The remainder of the mercury continues along the portion of the conical receptacle wall situated above the nozzles 23 and escapes through apertures 23 provided in the upper portion or the wall, the number of said apertures equalling that of the nozzles 23 and lying, in the example shown, in the same axial plane as the latter.

The mercury escaping downwardly through the upper openings 23 is received by channels 23 in a number of metallic contact members 21 arranged in an insulating manner on the inside of the cylindrical wall 3 of the receptacle I, said contact members being electrically connected with contact clamps not shown in the drawing to make connection with the external circuits. The electric insulation between the contact members 21 and. the outer receptacle wall'3 is constituted by a cylinder 28 of ceramic material, for example. The contact members 21 are formed as ejecting nozzles for a corresponding number of stationary connecting jets, and are to this end provided with a through passage 29, through which the mercury received in the channel 23 is discharged downwardly in the form of a compact Jet passing as a single elongated jet through a recess or a free space 33 in the lower portion of the contact member. To facilitate the return of the mercury to the common collecting place in the bottom of the outer receptacle 2, without the Jets then making contact with the mercury contained in the receptacle I, there is provided a screen or channel 3| in the path or the jet, said screen or channel being adapted to catch the mercury Jet and to cause the mercury on its passage through the perforation holes to be finely divided and transferred to the receptacle l in the form of a stream of particles or drops insulated from one another. The recesses 33 are open inwardly and situated on a level with the ejecting nozzles 23. The rotating connecting Jets discharged from the latter ejecting nozzles will consequently penetrate into the space 30 so as to make contact with the stationary connectin jet discharged from the channel 29. To prevent non-desirable movements of the quantities of the mercury flowing into the space 30, there are provided throughholes 32 in the contact piece 21 and in the insulating wall 28 opposite the ejecting nozzles 23, through which the horizontal mercury jets may continue into an annular recess 33 in the wall 3, said recess opening through passages 34 adjacent to the bottom of the receptacle I, so that the mercury may return this way to the lower portion of the receptacle. The annular recess 33 and the openings 32 are so arranged that no direct conducting connection may be produced between the contact pieces 21 and the outer receptacle I, after the horizontal jet has moved during its rotation past the contact piece so as to break the contact therewith. The mercury quantities returning to the outer receptacle are collected in the downwardly extended central portion 3, from which the mercury is driven up into the inner receptacle through the influence of the centrifugal force, in the manner indicated hereinbefore. To prevent the mercury in the outer receptacle from being brought into rotation by the friction against the inner receptacle, radial partitions 30 may be provided in the outer re ceptacle. The inflow oi the mercury through the opening 3 may also take place through a tube fixed in the outer receptacle and connected to said opening, said tube tightening against the wall of the inner receptacle by means of a labyrinth packing or the like.

Provided between the contact pieces 21 and the lass cover H are distance members 35, which may be made from metal or from insulating material, and which in a suitable manner confine that space above the channel 28 in which the ejecting nozzles 25 are moving.

As will appear from Figure 2, the channels 23 extend, the same as the channels 23, approximately over the whole length of the contact pieces 21, the stationary jets then escaping from the channels 20 obtaining a corresponding width. Since the rotating jets discharged from the nozzles 23 are preferably thread-like, the length oi the channel 23 in a peripheral direction will thus determine the length of the contact closing periods. In the example shown, it is assumed that the nozzles 23 and 25 are located opposite each other, contact closing thus taking place approximately at the same time between the feeding jet discharged from the nozzle 25 and the contact piece 21, on the one hand, and the stationary connecting Jet and the rotating connecting jet discharged from the nozzle 23, on the other hand. After that, the contact is maintained both ways, until the feeding jet discharged from the nozzle 25 moves past the fore edge of an insulating screen 36, which is arranged over the end of the contact piece. The feeding of mercury into the channels 23 being then interrupted, the contact will now be maintained only by the rotary connecting jet discharged from the nozzle 23. as long as this jet makes contact with the stationary connecting jet. This ensures that contact breaking will always take place between two mercury jets and that, consequently, the breaking of the feeding Jet at the edge of the insulating screen 36 may take place without sparking.-

The insulating screens 38 are so arranged as to cover the ends of two adjacent contact pieces 21, that edge of each individual screen which is remote in the direction of movement then determining the time for the closing of the current. By changing the position of said edge relatively to the channel, the length of the contact closing period may be varied.

Theperiodic circuit breaker may be arranged for the control of any desired number of external circuits by the arrangement of a corresponding number of contact pieces 21 about the inside oi the outer receptacle. In the example shown, there are provided nine contact pieces of said type.

To prevent the mercury as far as possible from entering the ball bearing housing". there are provided labyrinth packings 31 between the covers H and H, the lower pockets in said labyrinth packings then communicating through passages with the interior of the receptacle 2 for the purpose of deflecting mercury. The small quantities of mercury which might still penetrateinto the bearing housing l3 are carried off through apertures 38 in the bottom of the bearing housing, and filters may then be provided above said apertures, so that the bearing oil is prevented from finding its way out through the apertures. Such means to prevent the mercury from penetrating into the bearing housing are believed to be superfiuous, however, as the bearing housing I3 should permit of being filled with mercury, so

that the balls of the bearings are moving in mercury.

In order to prevent the feeding jets from disturbing the collection of mercury in the channels 26 on account of the velocity of such jets, whereby interruptions might occur in the jets escaping through the channels 29, it is possible, as shown in Figure 3, to provide a special distributing channel 39 between the nozzles 25 and the contact pieces 21, the mercury being then first caught by said channel, from which the mercury escapes immediately through apertures in the bottom of the channel, so that the mercury flows down into the channel 26 in a finely divided state, for instance in the form of line jets or small drops. Said channel 39 may extend continuously about the whole circumference. In this case, the current will be closed and interrupted solely by the contact between the rotating jet escaping from the nozzle 23 and the stationary let escaping through the channel 29.

I claim;

'1. Periodic circuit breaker with a circulating contact liquid, particularly for contact current changers, characterized in that the circulation system comprises a stationary outer receptacle and a rotating inner receptacle serving as a circulation pump, said receptacles being provided with electing nozzles for the contact liquid, so arranged that the contact liquid is divided during its circulation into a system of rotating jets and a system of stationary jets, the rotating jets discharged from the ejecting nozzles of the inner receptacle being adapted periodically to make contact with the stationary jets discharged from a number of mutually insulated ejecting nozzles in the outer receptacle.

2. Periodic circuit breaker according to claim 1, characterized in that the rotary part serving as a circulation pumpis adapted to feed both jet systems.

3. Periodic circuit breaker according to claim 1, characterized in that the feeding of the stationary jets is adapted to take place intermittently and synchronously with the contact closing between corresponding rotating and stationary jets.

4. Periodic circuit breaker according to claim 1, characterized in that the feeding of the stationary jets is adapted to take place intermittently and synchronously with the contact closing between the corresponding rotation and stationa y jets, means being provided for interrupting the feeding of contact liquid before the contact between the corresponding stationary and rotatin jets is interrupted.

5. Periodic circuit breaker according to claim 1, comprising stationary channels for the stationary jets, ejecting nozzles in the inner receptacle adapted to deliver contact liquid to said stationary channels, and distributing channels arranged between said ejecting nozzles and the stationary channels and adapted to receive the liquid from the ejecting nozzles and to discharge the liquid into the stationary channels in the form of drops so as to maintain the liquid supplied through the said ejecting nozzles electrically insulated from the stationary jets.

MARIUS HUGO WILHEIM WIDAKOWICH.

REFERENCES CITED The following references are of record in the die of this patent:

UNITED STATES PATENTS Number Name Date 690,973 Luschka Jan. 14, 1902 FOREIGN PATENTS Number Country Date 192,704 Great Britain May 1, 1924 676,808 France June 18, 1929

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