US1890470A - Electric current rectifier - Google Patents

Description

Dec. 13, 1932. s. RUBEN ELECTRIC CURRENT RECTIFIER Filed July 28, 1928 ELECTRO POSITI VE ELECTRONEGATIVE ALLOY avwentoz METALLIC COUMPOUND OF VT GRouP "0 Cu 5 E Patented Dec. 13, 1932 UNITED STATES PATENT OFFICE- SAMUEL RUBEN, OF NEW YORK, N. Y., ASSIGNOR TO RUBEN RECTIFIER CORPORATION, OF ENGLEWOOD, NEW JERSEY, A CORPORATION OF DELAWARE ELECTRIC CURRENT RECTIFIER Application filed July as,

This invention relates to electric current rectifiers and the like which employ asymmetric couples of the dry surface-contact variety.

Rectifiers of this type are characterized by the use of a body of relatively electropositive material, employed as one electrode element, disposed in electrical contact with a body of relatively electronegative material employed as the other electrode element. Such rectifiers depend for their operation upon the resistance and inverse current-blocking characteristics of the film which forms as the result of electrochemical action. Rectifiers of this character, known to the prior art, have been low in efliciency andlimited in their application to small currents, becoming-inoperative after short periods of use.

b The present invention has for its object generally to provide an improved device of.

the character described, which is efficient, economical and readily manufactured, and which, when operating, has a substantially inappreciable period of film-formation.

More specifically an object is to provide \an improved electropositive electrode element for cooperating with the electro-negative electrode element in devices of the character described, particularly where the electronegative electrode element is a compound of the sixth periodic group, in such manner as greatly to reduce and substantially to eliminate the period heretofore required for film formation at the junction, so that there is a substantially instantaneous direct current response at all times.

Other objects of the invention will in part be obvious and will in part appear hereinafter. t

The invention accordingly comprises the features of construction, combinations of el ements, and arrangement of parts, which will be exemplified in the constructions herein after set forth and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connectionwith the accompanying drawing, in which:

' volt, 60-cycle source of alternating current.

1928. Serial No. 295,971.

Figure 1 shows diagrammatically a rectifying unit arranged for battery charging service constructed in accordance with the present invention; and

. Fig. 2 is an enlarged cross-section of the cooperating electrode elements employed in the construction of units of the present invention, as shown in Fig. 1, the composition of the electrodes being schematically illustrated. I

Referring now to the drawing and particularly to Fig. 2, 10 denotes an electronegative electrode element against which is disposed an electropositive electrode element 11. These elements are cooperatively arranged in contact to have a junction shown at 12 where the inverse current-blocking film is formed, thereby constituting the elements of an asymmetric couple. A rectifying unit is made by operatively assembling one or more asymmetric couples, for example, as shown in Fig. 1. Here a unit is illustrated which comprises two groups of two couples each, the groups being inverted with respect to each other on opposite sides of the central conducting plate 13. At the outer ends of the groups of electrodes there are secured terminal plates 14, preferably in the form of standards, which are held in place by a rivet 15 passing therethrough insulated from the couples, but conductively connected to the terminal plates 14, this construction being substantially the same construct-ion as that shown in my prior Patent No. 1,649,742, patented November 15, i 1927. Between the head and nut on the bolt 15 and the terminal plates 14 dished washers 16 are interposed through which the bolt 15 resiliently applies its pressure to the plates and thence to the asymmetric couples held therebetween. Disposed intermediately of the groups of couples, at each side of the plate 13, ar terminal plates 17 which provide connecting terminals for the alternating current input supnlied from any convenient source of low voltage, for example, the secondary of the transformer shown at 18, which is a step-down transformer whose primary is indicated at 19 supplied from commercial source of alternating current, such as a 110- 'minum, magnesium or silicon.

The rectifying unit thus constructed of inverted groups of couples is a convenient mechanical embodiment of the four asymmetric couples here employed, arranged in a bridge circuit. Here the terminal plates 17 comprise one diagonal of the bridge, while the terminal plate 13 and the bolt 15 comprise the other diagonal. Hence the direct current output connections for charging a storage battery, such as shown at B, are connected respectively to the plates 14 and the plate 13.

In the practice of the present invention the electronegative electrode element as shown at 15 is any highly electronegative body which cooperates with the electropositive electrode element, there being sufficient resistance at the junction to form the inverse currentblocking film from the energy supplied by the voltage drop at the junction, as set forth in my co-pending applications, Serial No.

38,780, filed June 22, 1925, and Serial No..

113,009, filed June 1 1926. A metallic compound of the elements of the sixth periodic group is sufficiently electronegative in the electrochemical series to provide an operative electrode element. The metallic component of the electronegative electrode element may be one or more metals compounded with one or more of the elements of the sixth periodic group in the table of chemical elements as taught in my co-pending applications, Serial No. 51,524, filed August 20, 1925, and Serial No. 69,215, filed November 16, 1925. By way of illustrative example,.the

velectrone gative electrode element will here be considered a maximum valent compound of sulphur with copper,such as cupric sulphide.

The electropositive electrode element, here employed, is not a simple electropositive metallic element but an alloy, the components of which are highly electropositive and so chosen that the work-function at the junction is materially reduced. This may be achieved by selecting a relatively heavy electropositive metal of the copper family of the periodic table of chemical elements as a matr1x and alloying it with a lighter film-forming electropositive element chosen from the second. third and fourth groups in the periodic table of chemical elements, such as alu- A suitable alloy for this purpose has as the matrix a metal such as copper or silver. The following is an example of an alloy whichhas been ascertained -to have a suitable composition:

By weight Copper 80% Magnesium 20% The lighter constituent given in the above example is substantially uniformly dispersed in the copper matrix. and while magnesium is the only dispersed constituent named in the 'the other film-forming chemical elements chosen from the second, third, and fourth periodlc groups.

The amount of the dispersed constituent may likewise be varied within limits from that given in the above example; it having been ascertained that the lighter constituent may be taken within the limits of from 5 to 25% of the whole by weight in order to obtain the substantially instantaneous recti ying effect herein set forth.

An electropositive electrode element having this composition is adopted when in seiw ice with an electronegative electrode element of cupric sulphide to operate with high-current densities and otherwise shows excellent characteristics, is highly efiicient, and requires a very short period of time (usually materially less than a half-cycle) for film formation. The alloy described above has mechanical durability, resistance to a tendency to disintegrate in the presence of moisat the junction whereby the energy required to beexpended at the junction in the formation of the inverse current-blocking film is greatly reduced with the result that the filmforming characteristics. of the couple are almost instantaneous, so that the direct current response therefrom does not lag materially behind in supplying current in the manner heretofore experienced with certain types of rectifiers. This lagging characteri'stic may be described as film-forming hysteres'is.

It is also to be observed that by the use of an alloy electrode of the present invention the need in rectifiers of the dry type for an interposed resistance layer of a depth or extent heretofore customarily used is substantially gone, since the energy required for film formation appears to be reduced. This results also in reducing the internal resistance characteristics of the rectifier.

The work-function above referredto is not necessarilv the technical work-function generally implied when considering the energy necessary to overcome the attractive forces at the surface of bodies where elec tronic conduction is involved. The term as herein used, however, is intended to inu'fl s enerally the energy consumed in operati'vely p 'i. e. the storage battery B in the instance relatively electropositive and electronegative ,ployed, so that in case there is a tendency toward film disintegration at any point in the film at the junction, it is substantially instantly repaired and a full voltage direct current supply is had at all times. 'Also it is noted that, by reason of the use of the bridge connection of the asymmetric cells in the rectifying unit, the rectification of both halves of the alternating current impulses is not only accomplished but also the load,

shown, is in series between two asymmetric cells one of which does the rectifying while the other at'the instant rectification serves as a buffer, or cut-out.

Since certain changes may be made in the above construction and, different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall-beinterpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which as a matter of language might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In electric current rectifiers and the like, of the dry surfacecontact variety, an asymmetric couple arranged to have substantially uniform unilateral conductivity, which comprises electropositive and electronegative electrode elements adj acently disposed to have a rectifying junction therebetween, said electropositive electrode element being an alloy of an electropositive metal of the copper family of the periodic table of chemical elements with a film-forming electropositive chemicalelement, said electronegative electrode element being a metallic compound with a chemical element of the sixth periodic group.

2. In electric current rectlfiers and the like, of the dry surface contact variety, an asymmetric couple arranged to have substantially uniform unilateral conductivity, which comprises electropositive and electronegative electrode elements adj acently disposed to have a rectifying junction therebetween, said electropositive. electrode element being an alloy having a matrix of an electropositive metal of the copper family of the periodic table of chemical elements and a film-forming electropositive chemical element homogeneously distributed therein, said electronegative electrode element being a metallic compound with a chemical element of the sixth periodic.

group.

3. In electric current rectifiers and the like, of the dry surface contact variety, an asymmetric couple arranged to have substantially uniform unilateral conductivity, which com-.

prises electropositive and electronegative electrode elements adjacently disposed to have a rectifying junction therebetween, said electropositive electrode. element being an alloy of an electropositive metal of the copper family of the periodic table of chemical elements with a film-forming electropositive metallic element chosen from the second, third and fourth periodic groups, said electronegative electrode element being a metallic compound with sulphur.

4. In electric current rectifiers and thelike, of the dry surface contact variety, an asymmetric couple arranged to have substantially uniform unilateral conductivity, which commetric couple arranged to have substantially I uniform unilateral conductivity','which comprises electropositive and electronegative electrode elements adjacently disposed to have a rectifying junction therebetween, said electropositive electrode element be1ng an alloy having a copper matrix and asubstantial amount of magnesiumhomogeneously disbursed therein, said electronegative electrode element being a copper compound with a chemical element of the sixth periodic group. I q

6. In electric current rectifiers and the like, of the dry surface contact variety, an asymmetric couple arranged to have substantially uniform unilateral conductivity, which comprises electropositive and electronegative electrode elements adjacently disposed to have a rectifying junction therebetween, said electropositive electrode element being an alloy having a copper matrix and from about 5 to 25% of magnesium homogeneously disbursed therein, said electronegative electrode element being a maximum valent metallic compound with a chemical element of the sixth periodic group.

7 In electric current rectifiers and the like, of the dry surface contact variety, an asymmetric couple arranged to have substantially uniform unilateral conductivity, which comprises electropositive and electronegative electrode elements adj acently disposed to have a rectifying junction therebetween, said electropositive electrode element being an alloy havin a copper matrix and from about 5 to 25% 0 magnesium homogeneously disbursed therein, said electronegative electrode element being a maximum valent compound of copper with sulphur. I

8. In electric current rectifiers and the like, of the dry surface contact variety, an asymmetric couple which comprises electropositive and electronegative electrodes operatively disposed to have a rectifying junction therebetween, said electropositive electrode being an alloy compounded from copper with a film-forming electropositive chemical element and adapted to reduce the work-function at the junction of said electrodes, Whereby substantially instantaneous film formation is had at the junction of said electrode elements.

9. In electric current rectifiers and the like, of the dry surface contact variety, an asymmetric couple which comprises electropositive and electronegative electrodes operatively disposed to have a rectifying junction therebetween, said electropositive electrode coms prising an alloy of copper with magnesium taken substantially in the amount of 20% of the whole by weight whereby the work-function at the junction of the electropositive and electronegative electrodes appears to be substantially reduced.

10. In electric current rectifiers and the like, of the dry surface contact variety, an asymmetric couple arranged to have substantially uniform unilateral conductivity, which comprises electropositive and electronegative electrode elements adj acently disposed to have a rectifying junction therebetween, said electropositive electrode element being an alloy of copper with a relatively light highly electropositive metal, the electronegative electrode element comprising a compound of copper with sulphur.

In testimony whereof I afiix my signature.

SAMUEL RUBEN.

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