US1668201A - Current-rectifying unit and method of preparing the same - Google Patents

Description

May 1, 1928. 1,668,201

' E. R. GILL, SR

CURRENT RECTIFYING UNIT AND METHOD OF PREPARING THE SAME Filed Sept: 25. 1926 ar -Iv" 1 I 15- 14 @i/ML K %L [2 anvewtoz 5 /1 L J awn Patented May 1, 1928.

UNITED STATES EDWIN R. GILL, SR., OF YONKERS, NEW YORK.

dUBRENT-RECTIFYING UNIT ANI) METHOD OF PREPARING THE SAKE.

Application filed September 25, 1926. Serial No. 137,670.

The present invention has relation to the treatment of rectifying crystals, so called. whether natural or synthetic, whereby the slow and clumsy groping for the so-called sensitive spot is eliminated, making it possible to instantly locate and distinguish by the eye the position, form and limits of the sensitive portions of any crystal or mass of crystals.

My invention also has reference to a complete mode of treatment and preparation of rectifying units, as well as to the unit as complete i In m applications for United States atent, led April 13th, 1926, Serial Numers 101,608 and 101,609 I have described a mode of preparing rectifying apparatus in volving what I have termed the develop- ,ment of the latent rectifying power of crystals whether natural or synthetic, and

in my United States application filed Au gust 13, 1926, Serial Number 129,101, I have described a further advance in the art of developing this latent power, together with a novel mode of preparing efficient rectifyin units.

These patentapplications had reference to the development or increase of rectifying efficiency of these crystals under a conducting point preferably of silver, and the development as there described is carried on under such aoint after the sensitive spot on the crysta is located and the conducting point is applied to it.

Hitherto it has been found necessary to grope blindly over the crystal surface to nd the one or more sensitive spots on its surface by moving a conducting point or needle over said surface while observing the behavior of a suitable current indicator in circuit with the needle and the crystal. This is not'only a slow process, but, even when a sensitive spot-is found on a crystal, one cannot be sure that the best spot has been located. Moreover it is frequently found that the crystal tested is substan; tially worthless as a rectifier, and all the time spent in thus groping over its surface proves to have been wasted. I

I have made the important discovery that, by a simple, rapid and inexpensive method of surface development analogous to the point development above mentioned, all of the surfaces of acrystal mass may be made to reveal to the eye the relative rectify ing powers of the various portions exposed.

in question consists in moistening the surface with water or dilute acid, preferably the latter, while passing an electrical current through the same.

Inasmuch as I have had marked success with native iron pyrites, and as the present invention relates partly to the finishing of a commercial rectifying unit, I shall hereinafter describe my process in its preferred embodiment with reference to the preparation of a finished unit made of pyritcs. It is to be understood, however, that my broad invention is not limited either to this material or to this particular purpose.

In the accompanying drawings Figures 1, 3 and 4 are perspective views of a preferred form of rectifying unit in different stages of preparation, and Figure 2 is a diagram illustrative of the preferred process of surface development.

As already described in my earlier patent application, Serial Number 129,101, I first cut out of a mass of pyritcs or its equivalent a cube, such as is shown in Figure l at 10. This will have a bright golden glitter which is substantially uniform over the entire surface, as is indicated in Figure 1 by the absence of all shading between the outlines of the cube. The eye cannot distinguish which portions, if any, of these surfaces are useful in rectification of an alternating current.

In' order to impart the surface development above mentioned I may proceed as follows. A flat/plate 11, rcferably of carbon is moistened, preferab y with dilute sul-- phuric acid of the strength commonly used in secondary battery cells and the cube 10 is set down upon it. The top of the cube then moistened in the same manner, and a flatflbottomed conductive'contact piece 12, preferably of carbon is laid on the cube.

- current.

At 13 and'14 are shown wires representing the two sides of anelectric circuit. This may be either direct current or alternating I have also used direct superimposed upon alternating current. I find alternating current best for this purpose, however. The carbon plate 11 is laid upon a metal plate 15 which is connected by the wire 16 to one side 14 of the current supply, or any means may be employed to bring the plate 11 into circuit. The wire 17 connects the carbon-contact piece 12 with the opposite wire 13.

\Vhile current is thus passing through the moistened surfaces of the cube 10, the surfaces of the conductors 11 and 12 may be vmade to rub across the cube to insure uniform and efficient contact and to expedite the process.

The amount of current used and the time employed will vary with circumstances. With a cube of pyrites a quarter of an inch across I have obtained excellent results with an alternating current of six volts by continuing the process for a few secondssay ten to twenty-five.

This step in the process being finished, the cube is carefully washed and preferably dried by evaporation, after which the proc- ,ess may be repeated until all six faces of the cube have been developed.

Figure 3 shows in a conventional form a picture that may be taken to roughly exemplify the appearance of the faces of the cube after the treament above described; it being understood, of course, that in actual practice the markings and shadings will var in form and location indefinitely.

F or pur oses of example the sides of the cube have n represented in three shades, pure white, light grey and dark grey. The pure white re resents a steely, hard surface which is brig t in appearance and conductive, but without appreciable rectifying power. There will also be observed patches represented by the dark gre which are actu: ally uite dark and lack uster, somewhat resem ling soot. tain degree of rectifyfing power, but they are very inferior to t ose parts of the sur faces conventionally shown in Figure 3 by the light grey shading.

These have a dull silvery aspect and invariably exhibit the maximum of rectifying power. Of course, the sharp limits between these various parts as shown in the figure are seldom found in practice. The various surfaces ma shade off into one another; but as a r'u e. the steely relatively useless portions are rather sharply defined.

\Vhen the entire cube has been developed in this way to make it reveal its true properties to si ht, the various faces are in-' spected to etermine whlch will give the These portions have a cer-' rubbin on emer cloth or otherwise grin ing. his has t ree uses. It increases the conductivity of these faces; it destroys any rectifying activity which might act counter to the effect desired from the chosen face; and it fits these faces. to be electroplated, preferably with copper.

This electro-plating is the next step, being accomplished in a well known manner; the

chosen active face being protected and ke t undisturbed and unrubbed so far as possib e.

The finished unit is thus completed and presents the appearance shown in Figure 4, wherein the sides other than the active top are shown covered with a copper coating 17.

\Vhen this unit is placed in operative position under the conducting point which conveys current to it, a further point development may be obtained. which increases its efficiency. This is described in my earlier application Serial Number 129,101.

The process above described may be indefinitely varied and may be applied to rectifying materials of various kinds in any stage of use and any condition without departing from my invention. It is also to e understood that the appartus herein described exemplifies merely the principles upon which commercial apparatus should be preferably constructed in carrying out my rocess.

W rat I claim is- 1. The process of treating the surface of a current rectifying substance to make vis-.-

ible the more sensitive areas, which consists in moistening said surface and passing an electric current through said surface. i

2. v The process as in claim lwherein dilute sulphuric acid is used to moisten the surface. v

3. The process as in claim 1 wherein two opposite surfaces are moistened and current is passed through both.

4. The process as in claim 1 wherein alternating current is used.

5. he process of treating the surface of a current rectifying substance to make visible the more sensitive areas which consists in moistening the surface and subjecting the same to friction while passing an electric current there-through.

In testimony whereof I have hereto aflixed mgy signature on this 24th day of September, 1 6.

EDWIN R. GILL, SR.

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