US2310026A - Thermopile - Google Patents

Description

ma, 2, w43., F. R. HJIGLEY 2,310,025

THERMOPILE Fild Nov. 14, 1940 IL 5 a? INVENTOR.

'fQ/KE-Mc-MEY ATTORNEYS t. t t n. igley, Clevelan energias, om, assignorto The Bryant Heater Company, Cleveland,

Ohio, a corporation of Ohio application November 14, 1940, senat vantistatic a (ci. 'ies- 4) invention relates Vto improvements in thermopiles, and has reference to a novel construction of thermope as well as to amethod oi making the same.

In control apparatus thermopiles areused to operate switches or valves; The current that may be set up by any one couple is of course quite small, and in order to build up a potential of sumcient amount a series of couples must be combined to give an additive result.4 The cost of such a thermopile as heretofore constructed has been high, and that fact has-tended to limit `the number of couples to whateveris found to be absolutely essential. 4 I

The present invention seeks to provide a thermopile ofany required number of couples at a relatively lowcost, and one in which the application of heat to the hot junctions may be accom- Iplished easily and eiiiciently.

The primary object of the invention therefore is the provision of .a low cost high efliciency thermopile. I i

Another object is the provision of a novel thermopile mounting, particularly adaptable to control mechanism for gas burners or the like.

Other objects and features of novelty will appear as I proceed with the description `of those embodiments of the invention which, lfor the purposes of the present application, I have illustrated in the accompanying drawing, in which Fig.-1 is an'elevational view of a thermopile constructed in accordance with the invention.

Fig. 21s an end view of the same.

Fig. 3 is an elevational view partly broken away and partly in section illustrating another embodiment of the invention.

Fig. i is an end view of the same partly in elevation and partly' in section.

, Fig. 5 is a top plan view of a further modification of the invention.

Fig. 6 is an elevational view, partly in vertical section, of the construction shown in Fig. 5.

Fig. 'i is a view similar to Fig. 6 of a slightly I modified form of the invention.

4termed.. Various metals or alloys may be usedl for the wire coil, and various metals may be used for the coating on the coil. As examples of such that the repeated expansions and contractions due totemperature changes may not affect adversely the adherence of the coating to the wire. The application of the coating to the wire may fbe eected by plating, dipping. spraying, etc. I

prefer however to plate it onto the wire. The

wire after being formed into a coil of the length Iand diameterI desired may be immersed p'art-vvay in a platingbath. Preferably one-half of the coil is immersed and this half is plated, so that after the coil is removed from the plating bath one-half of each convolution is plain wire and the other half is coated wire, and the two Junctionsbetween the coated and uncoated portions of each convolution are spaced preferably 180 apart.

When the plating, or coating by other method,

has been completed and the coil has been removed from the coating apparatus, it may be permitted to remain straight, as in Figs. 1 to 4 inclusive, or Vit may be ,bent into a ring as in Figs. 5, 6 and 7. Referring first to Figs.'1 and 2, one set of junctions between the parts I 0 4and II is in this case joined mechanically but not electrically by a pair of bars I2 and I3 that are held together by high temperature cement 9, which also serves.`

to rmly fix the convolutions in properly spaced relation and to transmit heat to the junctions.

Heat is applied to one of these bars by names I! or other suitable means.' The bars I2 and I3 are made of some non-metallic refractory material which is not a conductor of electricity, for example porcelain or oven glass.-

In the form of the invention illustrated in Figs. 3 and 4 the straight coil is arranged with one set of junctions at Vthe top and the other set at the bottom, and a tubular fluid fuel burner I5 is introduc'ed'into the coil with the burner openings in a row at the top thereof. When the burner is on the flames heat the junctions above them.

materials I may mention a ferrous alloy as the Furthermore the draft created by the heat from the flames causes a ow of cool air upwardly over the lower set of junctions which helps to maintain a wide difference in temperature between the upper and lower sets of junctions. In order to accentuate this eiIect I may partially enclose the coi1 in a non-metallic refractory electrical insulation material it providing an opentopped housing' with an alr passage I1 beneath the lower set of junctions, so that the air now induced by the natural draft is conned somewhat and caused to pass over the lower junctions. Wnere a thermopile of this design is used in control apparatus for gas burners the tube I5 may be continued beyond one end of the coil where it may be provided with a larger orifice in order to function as the pilot of the system.

In the construction. oi.' Figs. 5 and 6 the coil after being coated in lthe same manner as before is bent into a hollow ring, each convolution however being separated from adjacent convolutions by an air space or other electric insulating medium. The coated portions ofthe convolutions in this instance are positioned at the top of the coil in order that one set of junctions may fall at the inner border of the ring and the other set at the periphery of the ring. The coil then may be associated with a pilot or other burner I8 adapted to play a flame upon all of the inner junctions.

Instead of directing a flame against the inner junctions in the ring form of the device, the inner portions of the convolutions may be sprung into an annular recess I9 in a porcelain or other heat conducting and electric insulating post 2U, the inner junctions then being heated by conduction from a flame 2l which is directed against the post at a point somewhat removed from the wire coil. Care must be taken as before to maintain the inner parts of the convolutions electrically separated.

While as previously stated the coating of the wire coil may be accomplished in diierent ways, the procedure which I prefer at `the present time is electroplating. Apparatus which may be employed in this step of the method is illustrated schematically in Fig. 8 where 22 is a tank containing electrolyte 23. 24 represents an anode of chromium, nickel, silver or other metal which it is desired to deposit upon the coil. 25 is a combination support and conductor which is caused to extend through the coil from end to end and is then rested upon opposite walls of the tank. The coil then hangs down into the electrolyte which is maintained at a level such that approximately half of the coil is immersed. 26 and 21 represent electric conductors for transmitting a current of electricity into and through the apparatus. It will be obvious that by the Patent No. 2,510,026.

FRANK4 R. HIGLEY.

operation of this apparatus the desired coatingmay be applied to the desired portion of the coil, generally one-half of the same.

Having thus described my invention, I claim:

1. A method of making a thermopile which comprises helically coiling a length of wire, coating one longitudinal halt of said coil with a metal different from that of the wire to form two junctions of coated and uncoated wire approximately apart for each convolution of the coil.' bende ing the coil either before or after the application of the coating to form a hollow ring with corresponding junctions at the inner border of the ring and providing means for applying heat to said last named junctions. the remaining portions of the convolutions being left free and unobstructed to facilitate the rapid dissipation of heat.

2. In a thermopile, a torus comprising a helical 'coil of metal wire having circular hollow' convolutions, a coating of a different metal on onehalf of each convolution, the coated and uncoated portions oi. the convolutions lying upon opposite sides of a plane through the centers oi the convolutions, whereby one set of Junctions between coated and uncoated portions are arranged .in the inner circle of the torus, and means for applying heat to said set of junctions.

3. In a thermopile, a helical coil of metal Wire bent to the form of a torus, a coating of a different metal on one-half of each convolution. the coated and uncoated portions of the convolutions lying upon opposite sides of a plane through the centers of the convolutions, whereby one set of junctions between coated and uncoated portions is arranged in the inner circle of the torusl and an electric insulator and heat conductor engaging the junctions at the said inner circle of the torus.

4. In a thermopile, a torus comprising a helical coil of metal wire having circular hollow con volutions, a coating of a different metal on onehalf of each convolution, the coated and uncoated portions of the convolutions lying upon opposite sides of a plane through the centers of the convolutions, whereby one set of junctions between coated and uncoated portions is arranged in the inner circle of the torus, and a heat conducting post of electrical insulation resiliently mounted in the inner circle of the torus.

FRANK R. HIGLEY.

CERTIFICATE or coautorfor.4 f

February '2, 191e.

oftgibhereby certified thai-.error appears in the 'printed3 specification ond- .ove numbered patent requiring correction as follows: Page 2 secmo glum, -lines 29 and 5o, Claims, rerthe -woz-esseci come *In either?V4 pl a helical coil ofI metal wire bent to the form of a torus read 4 In e. thermopile, a'torus comprising e. helical coil yof metal wire-ha lrllg r'ular hollow ,eonvolutions,;v and that .the said 'Letters Patert s ou streed with' this' o the record of' the 129.89 inctlri'ettxel.that the *same mgy enfom to ysigned and sealed this 415th .day er April, lr.' D. 1915.

Henry van Andale,

. CERTIFICATE oF conmzc'-rrq1r.v 'Patent No. 2,510,026. I Eebmmjg. 191,15. FRAM; n. Hmmmg L It .is hereby' certified thefterror appears in the printed' specification' of the above nnmbered patent redul'ring correction as follows: Pege 2, seci 0nd column, lines 29 and 50, claim, furthe wordaand comm. 'In a thermopile,a helical coil oif'metal wire bent tothe forgn of a torus]I vread ing'circular hcllow c0nvo1ut1ons,; and that .the .said 'Letters Patent should beregdwith' this correction therein that the same mey conform to the record of the cese' in the'Pat-ent Office. v l

eigned and sealed this ,15th .any f April, A D. 1915.

- I Henry van Arsdle, (Seal) Acting Commissioner` of Patents.

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