US437412A - Marcel depeez - Google Patents

Description

(No Model.)

M. DEPREZ.

RHEOSTAT 0R RHBOTGME.

Patented Sept. 30. 1890.

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MARCEL DEPREZ, OF PARIS, FRANCE.

RH EOSTAT OR RHEOTOME.

SPECIFICATION forming part of Letters Patent No. 437,412, dated September Application filed February 24, 1888. Serial No. 265,206. (No model.) Patented in France October 5, 1887, No. 186,243,- in England February 7, 1888, No. 1,843, and in Belgium February 7,

To all when@ t may concern:

Be it known that I, MARCEL DEPREZ, electrician engineer, of Paris, in the Republic of France, have invented certain new and useful Improvements in Rheostats and Rheotomes, (for which I have obtained Letters Patent in France, dated October 5, 1887, No. 186,248; in Great Britain, dated February 7, 1888, No. 1,843, and in Belgium, dated February 7, 1888, No. 80,5G2,) of which the following is a specification.

In nearly all applications of electricity to industrial purposes it is usual to employ rheostats essentially composed of more or less resisting conductors in which a part of the electric energyis expended in heat. Vhen great electric powers are employed, developed by very intense currents, the rheostats expend very notable quantities of energy, and it becomes proportionately diiiicult to construct them with the conducting bodies usually employed, especially metals. The problem is even more complicated if the currents employed are of high tension. Powerful hightension currents do not bear the introduction of rheostats except with special precautions, and cannot be suddenly broken by the ordinary means. In practice metallic rheostats are always employed. These act by introducing the resistances into the current by successive fractions. NVith currents of high tension this process produces violent and sudden changes of potential, which cause extra currents and dangerous sparks. On the other hand, the currents cannot be broken Without having first reduced them to a very weak intensity, without which extra currents and sparks, which are very prejudicial to the apparatus, are engendered. This condition with high-tension currents requires the employment of very high resistances, which never quite fulfill their object when they are obtained with the aid of metals.

Now, the rheostat-s which form the subject of the present invention permit of obtaining very easily as high a resistance as is desired, and of introducing it into the circuit by following a continuous variation, of maintaining it at a determined value with an absolute pressure, and of breaking the current without stats are applied to currents a sensible spark. In order to obtain these result-s I employ liquids as the resisting bodies. This employment of liquid is not newin principle. It has been sometimes followed in laboratories and in experiments g but, for reasons hereinafter explained, liquids have never been employed industrially, and there is no liquid rheostat in current use. The arrangements hereinafter described have for their object to allow of this industrial use of liquids, and to thereby obtain all its advantages.

In all these arrangements there are five general characteristic and novel features, which I will first explain.

The first consists in the nature of the liquid employed. In the laboratory experiments above referred to more or less concentrated saline solutions have been used; but according to this invention I employ ordinary water. I use saline solutions only exceptionally, in cases where it is necessary to reduce the resistance-such as, for example, when rheoof relatively weak tension or of great intensity.

The second characteristic feature is that, in order to be able to keep the rheostat indefinitely in the current, I provide for a continuous renewal of the liquid, so that the electrodes are immersed not in a stagnant mass but in a current of liquid. The use of ordinary water makes this method very simple, as it is simply a continuous flow. In the case of saline solutions the same liquid can be kept circulating through the rheostat (and through a refrigerator, if necessary) by a pump or other analogous apparatus.

The third characteristic feature of my improved rheostat is that the electrodes never come in contact in the liquid, so that the resistance ot' the rheostat is never actually reduced to Zero. This I consider a great advantage, for when metallic contact is broken within a resisting iiuid, and when the circuit carries a current of considerable tension, the spark occurs between the electrodes within the iiuid, although such spark is never as great and destructive as if the circuit is broken suddenly outside of the resisting fluid. I have, however, provision for removing the rheostat completely from the circuit IOO by short-circuitin g the same loutside ofV the iiuid by connecting the metallic conresisting ductors which lead to the rheostat. This connection takes place automatically and by the continuation of the action which has reduced the resistance to its minimum value. The rheostat is then outside the circuit. In` versely, when it is desired to reintroduce it, the metallic contact is first disconnected, and then the resistance of the rheostat' is increased.

The fourth characteristic feature applies to rheostats which are employed as rheotomes. In this case, in order to interruptthe current by one of the arrangements which are hereinafter described, provision is made for the electrodes or one of them ceasing to be 'in contact with the liquid. When one ofV the electrodes has to leave the liquid before the other, it is important for this to be the one which is connected to the positive pole-that is to say, the one by which the current enters the rheostat.

, The fifth characteristic feature is that the electrodes which conduct the current to the rheostat and lead it away therefrom are not necessarily the current, such as carbon or platinum, for example, which are expensive and fragile. I

` use, on the contrary, ordinary cheap metals,

such as iron or lead. Their waste or wear in the apparatus is very slow, and the renewal by like electrodes is inexpensive.

Having set out the general characteristic features of novelty, I will now proceed to describe the arrangements for carrying them into effect with reference to the accompanying drawings, in which I liaveshown several forms of apparatus embodying my invention.

j They are divided into three classes, viz: First,

arrangements in which the electrodes are movable; second, arrangements in which the electrodes are fixed aud the liquid is movable, and, third, arrangements in which neither the electrodes nor liquid is movable.

Figure 1 represents a vertical section of a rheostat in which one electrode is movable. Fig.2 is a like view of a rheostat in which both electrodes are movable. Figs. 3, 4., 5, 6, 7, and 7bis are also vertical sections of rheostats in which the highresistance iiuid is movable, while the electrodes are practically stationary. Fig. 8 is a similar view of an apparatus in which an insulating partition between the electrodes is movable within the -erably three,

'ner F to the other pole.

formed of metals or materials. which are not attacked under the action of consists inx placing in a vessel athrough which a current of liquid flows, two, or prefelectrodes F F F', the two outer F F being connected to one pole and the i11- It suices to raise the electrodes F in order to gradually increase the resistance and to withdraw it from the liquid to break the current withou't producing extra current even by moving the electrode rapidly. Both electrodes may be movable and rise from the liquid together. (See Fig. 2.) Y Instead of a narrow vessel which only allows of a vertical movement, I can employ a long vessel or trough which allows of the electrodes being moved away from each other before withdrawing one of them in order to break the current. The variation of the resistance is thus more regular. A complete apparatus `for effecting this is described farther on. 'lhe plates forming the electrodes have iianges at their lower ends. These flanges retain for an instant a film of liquid when the plates are raised from the body of the liquid, whereby the resistance of the circuit is enormously increased at that point bei.

fore the circuit is entirely broken, and thereby entirely prevent the formation of arcs and sparks wh en the current is broken. Thisprovision is useful, but is not considered necessary.

In the arrangements above described, in

which the electrodes are movable in the liquid,l

when the electrodes are rising the whole body of liquid continues to conduct the current,- `the resistance being increased only by the diminution of the submerged surface of the electrodes; but when, on the other hand, the body of liquid diminishes at the same time as the submergedsurface of the electrodes the resistance increases with greater regularity.

, Fig. 3 represents an arrangement in which the body of liquid diminishes. The electrodes F and F are fixed in an insulating-vessel ct.

'The liquid enters the vessel by an orifice A and leaves by the orifice B of a vertical tube made of non-conducting material. This tube can be moved endwise in a gland or stuiiingbox C, and the height of its upper end determines the level of liquid between the electrodes, and consequently the resistance.

Fig. it represents-another arrangementin which, by means of a bell o r inverted vessel b of insulating material descending around an electrode F, the liquid-level can -be lowered. For more security this bell can be double, so as to surround both the electrodes F F', as seen in Fig. 5. The liquid can bev moved without moving' the bell or inverted vessel either by blowing into the bell b, in

which the electrodes are, (see Fig. 6,)*or byv forcing it by a pressure of air from aclosed reservoir a, Fig. 7, into a vessel b', in which- TOO ITO

W'hen neither the electrodes nor the liquidy are made to move, the variation of the resistance be effected by introducing an insulating-partition CZ between the electrodes. (See Fig. 8.) This mode can be very eficiently carried out by the arrangement shown in Figs. 9 and l0, in which the rheostat is in the form of a fiat cylindrical vessel capable of turning upon a horizontal axis o 0. The vessel is partly divided by a vertical semicircular partition C, parallel to the ends. The electrodes F F are likewise semicircular and are ixed. They are submerged in the liquid, the level of whichis at N and the renewal of which is effected by connections at the center of the vessel. By turning the vessel the insulatingpartition can be completely disengaged from or more or less engaged between the electrodes or interposed entirely between them, thus causing the resistance to vary from the minimum to the maximum by a simple and rapid operation. Vith this arrangement the vessel can inversely be fixed, the insulatingpartition C being dispensed with and the electrodes being movable around the axis. They could then be more or less submerged in the liquid or be entirely withdrawn from it. The variation of the resistance would,how ever, be less regular than with the other arrangement.

The arrangement which I will now proceed to describe, and which is represented in. Figs. ll and l2, is a veryl practical i'orm of apparatus of the class in which the electrodes or one of them are movable. The liquid is contained in a vessel or trough V of insulating material. It enters by an orifice A and leaves by an orifice B. Its level is determined by a partition Il, the height of which can be varied, if necessary. The electrodes F F are each formed ot' parallel metallic plates connected together. The electrode F is iixed and receives the current from a binding-screw a. The electrode F is movable and suspended from an axis o. The plates of this electrode are parallel with those of the other, and can enter between them, as is indicated in Fig. l2, but without touching them. The bottom of the vessel is curved, the curve being struck from the axis from which the movable electrode is suspended. The current reaches this electrode through this axis.

The rod which supports the movable electrode is connected to a lever G, and a counter-weight tends to keep the rheostat open, so as to avoid accidents if the rheostat should by mistake be left to itself. According to the position given to the lever G the movable electrode F will either be near the electrode F, and the resistance will then be very small or moved away from this electrode, the resistance being proportionately greater, or if the electrode F be moved quite out of the water the current will be broken. On the axis of the lever is a inger C connected by a rod D of insulating material to a handle m adjoining the lever-handle M. Vhen the movable electrode F reaches the bottom of the vessel and the lever-handle M is let go, the iinger C touches a block E and makes a metallic contact, putting the rheostat out o'E circuit inversely It the rheostat is to be used, the two handles areV grasped together, and consequently the finger C is raised and the rheostat is automatically put into the circuit.

That I claim, and desire to secure by Letters Patent, is-

l. In a rheostat or rheotome in which a liquid forms the resisting body, the combination, with the vessel for containing said liquid and with the electrodes, of an inlet for said liquid and an outlet for the same, whereby a continuous flow and consequent renewal of the liquid is maintained, as set Jforth.

2. In a liquid rheostat or rheotome, electrodes formed with langes at their lower ends, whereby when said electrodes cease to be submerged in the liquid a film is momentarily retained by said flanges, as set forth.

3. In a liquid rheostat or rheotome, the combination, with a vessel V, having an inlet A and outlet B and with the electrodes F and F', of the rod I), lever G, contact-finger C, contact-block E, rod D, and handles M and in, as described and shown, for the purpose set forth.

In testimony whereof I have signed my name to this specification in the presence ot two subscribing witnesses.

MARCEL DEPREZ.

Vitnesses:

RoB'r. M. HooPER, ALBERT COHEN.

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