US151568A - Improvement in thermo-electric piles - Google Patents

Description

UNITED STATES PATENT QETTGE.

CHARLES CLAMOND, 0F PARIS, FRANCE.

IMPROVEMENT IN I'HEnIvI-Erscmlc PILEs.

Specification forming part of Letters Patent No. 151,668, dated June'2, 1874; application lcd May 22, 1874.

In my improved thermo-electric battery the' groupngof the barsiseylindrical; but for batteries of large dimensions I can impart to the assembled bars a rectilinear contour. In this case the bars would be arranged insnpcrposed rows. i

It is noticeable that thermo-electric bars, as heretofore Ina/Je, preserve their property for but a short time. Under the continued action ofheat, and the successive beatings and coolings to which they are subiected,.they acquire an internal resistance, which constantly in;l

creases, while the electric force' remains the same, which resistance, in time, becomes such that the current generated` by the heat can give but a very feeble and almost inappreciable quantity of electricity. lon'Ictimes,indeed, there takes place even aconpletc solution of continuity, which reduces the electric ci'ect to almost nothin. 'I have ascertained that this grave defect is due to two causes. On the one hand, the surface of contact of the metal strip or bladewith the crystallized metal or mi neral becomes oxidized, and consequently resistant to the passage of the `current. (.)n the other hand, the crystallized barv cracks or presents' eleavages, which, though imperceptible to the naked eye, increase and permit the oxidation to extend into the interior of the bar, which thus becomes more and lmore resistant. These causes have the effect of rapidly impairing the efficiency of the battery.

I remedy the 'aboveoted diticnlti'es, rst, by new method of uniting the metallic strip or blade with the part of the bar exposed to the heat; second, by casting the bars in heated y molds.

The nature of these improvements will be readily understoodk by reference to the accomT panying l:lrawing.;, in which- I Figure 1 is a vertical central section, andv Fig. 2 is a plan, ot' my improved pile. Figs. 3 and 4 represent, in'detail, the manner of unit* ing the blades or strips with the bars.

The elements A A A are grooved in the form of circular crowns, isolated onefrom the other by mica or amianthus. In this instance 1 employ disks or washers a 1.a of amiaiithus'.,

The ,elements A A, superposed one on the other, form a cylinderr to, the interior of .which heatis applied. The heat can be obtained by means of gas, which is used as follows: A tube, B, of refractory earth, closed at top and pierced with small holes b in its sides, is placed within the central chamber ofthe pile, leaving between it and the inner ends of the bars au annular space, open above and below to the atmosphere. lo Ythe base of thc tube B is attachechthe cylinder C, closed'at bottom and communicating with the pipe E, which con` nects with the source of' gas-supply. This pipe is provided with Bunsen burner e, which mingles gas with the air entering through holes o o. The mixture of gasand air passes to the refractry tube "B, whence it issues through the holes b into the annular space around the tube, .where .it is burnt in contact with the air entering` said annular space through the lower openiugp. This air, being of necessity preliminar-ily heated, renders the combustion very perfect. The bars thus areheafnd both by radiatiou from the refractorytube, which soon becomes red hot, andV by direct action of the' iiame and" products of combustion, which are brought in contact with the inner ends ofthe bars. Each bar provirjled with two blades or strips,p n, that serve to collect the electric current. .The former, 1I, is situated on the exterior at the positive pole, the latter, n, is fitted v to the inner part of the bar at the negative pole. rlhe manner of uniting these strips with electrodes of the buttons N4 P depends upon the nature of the current to be developed,

whether tension or quantity-'In Fig. 2 the strips are represented as arranged for tension. The strips p are attached in the usual way to the exterior and cold part of -the bar. The union'of the strips n with the bars, said strips being in contact with the inner and heated portions of the barsyis, howeveneffected during the casting of the .bars and in theI '.'following manner: The metallic strip', placed in advance in the mold, is provided with a small appendage that, during the castingg` of the bar, will be taken and incorporated in the material ofthe bar itself. This appendage isa. metallic ring o'r bent, I', united, by

solder, with strips n, and'formed of a small strip narrower thon n, as seen in Ifig. 3; or this ring may be formed in the Strip 'n itself, which is reduced in width :tt the part s, which is then bent up into ring form, es shown. The extremity of the strip n is folded over, in order to double the thickness. The width of the metal that forms the ring should be a little, .less than half of that that forms the strip n.

The strip n, thus furnished with a bent or ring, is, after being thoroughly-cleaned, placed in the mold and suitably arranged, and the 'metal or mineral constituting the body of the bar is rnn in and envelops the ring r, which is thus incorporated into the ber and assumes an intimate and permanent contact between' the strip and the bar.

In making the bars, I make use ot' any suitable thermo-electric substance, preferably the compound metal known as Marcus metal, composed of about two'parts of antimony to one part of zinc. Whatever may be the' metal employed, it is impossible to avoid cracking and -cleavage so long as it is run into cool molds,

since, under sucli conditions, crystallization cannot be uniform and regular. I completely obviate this ravedefect by preliminarily heating the molds to a. degree bordering on the fnsingpoint of the 'metal or mineral to. be cast. The latter, melted and agitated in a crucible, is run into the heated molds, which are then placed in a. medium, wherethey will cool qnite A slowly. I thus obtain bars which are' perfectlir homogeneous, and consequently will not crac e The elements A are held together between two plates or skeleton frames, t, hound togoth-er by tie-rods u passing through their The products of combustion escape through alateral orifice to the chimney. For smellK piles coke een be replaced by charcoal or artiiici'al fnel.

Having4 described my invention, what' I claim, anddesire to secure by Letrs Patent, 1s'4 1. The mode of uniting the negative strip with the bar by'means of a metallic ring or bent, soldered to or making part ofthe strip,

and incorporated into the body of the bar by casting, substantiallyas set forth.

2. The' manufacture of the bars ot' thermoelectric piles, by casting' thel same in molds preliminarily heated to ncurthe fusing-point of the thermo-electricmeterial, as set forth.

' 3. The combination, with the elements A,

of the central perforated radiating cylinder B,

made of refractory materinlhthe pipe E, and' the Bnnsen burner e, the come' being arranged and operating together, as herein shown and 'set forth. l

to this specitication before two subscribing witnesses. V V

' C. CLAMOND. Witnesses:

DAVID T. S. FULLER, ALBERT CAREN.4

In testimony whereof I have signed my name

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