US2520679A - Thermoelectric generating device - Google Patents

Description

1950 H. J. FINDLEY 2,520,679

r TI'IERMOELEC'I'RIC GENERATING DEVICE Filed July 20, 1945 2 Sheets-Sheet l OGQOQOQOGO )6 l 7 IN VEN TOR. 75 1 HOME/30 J F7/VOLEY BY M WW am 1950 H. J. FINDLEY 2,520,679

TI-IERMOELECTRIC GENERATING DEVICE Filed July 20, 1945 2 Sheets-Sheet 2 INVENTOR.

7 Z//7 0 I Fix 01E) W5 4 BY W MW 51% Patented Aug. 29, 1950 UNITE THERMOELECTRIC GENERATING DEVICE Howard J. Findley, Chardon, Ohio, assignor to Eaton Manufacturing Company,

Cleveland,

Ohio, a corporation of Ohio Application July 20, 1945, Serial No. 606,121

6 Claims.

This invention relates to thermoelectric generating devices and, as one of its objects, aims to provide an improved construction ailfording a device of this kind which can be economically manufactured and operated and which is small and compact in relation to its electrical output capacity or rating.

Another object of this invention is to provide an improved thermoelectric generating device of the character mentioned, which will operate in a quiet and satisfactory manner and which embodies a relatively large number of thermocouple elements such as to deliver a high voltage suitable for direct operation of radio apparatus and for other purposes.

A further object of the present invention is to provide a thermoelectric generator of this kind, in which the thermopile has a plurality of groups of thermocouple elements for the delivery of different terminal voltages and current values and wherein one group of thermocouple elements of a, relatively heavier cross-section is located nearest the fuel burning means.

Still another object of the invention is to provide an improved thermoelectric generator of this character, which will operate on relatively inexpensive fuel such as kerosene and can be used to advantage in remote areas where a commercial distribution of electricity is lacking.

Yet another object of the invention is to provide an improved construction of the character mentioned, in which the thermopile is a selfcontained unit supported on a base containing a fuel burning means and'is removable or liftable from the base so as to afford access to the fuel burning means and also to enable the thermopile unit to, be placed on some other fuel burning means such as over a burner of a conventional stove or lamp.

The invention can be further briefly summarized as consisting in certain novel combinations and arrangements of parts hereinafter described and particularly set out in the appended claims.

In the accompanying sheets of drawings,

Fig. 1 is an elevational view partly in section showing a thermoelectric generating device embodying the present invention.

Fig. 2 is a plan view of the device with portions oi the cover and thermopile broken away.

Fig. 3 is a partial end view of the thermopile further illustrating the construction thereof, and

Fig. 4 is a partial sectional view taken through a portion of the wall of the thermopile as indicated by line 4-4 of Fig. 3.

Proceeding now with a more detailed description of the improved thermoelectric generating device, the drawings show the present embodiment of the device as comprising in general a base or support In containing a fuel burning means [I and an upright tubular thermopile l2 extending abov the base and forming a stack for the fuel burning means. As will be explained more in detail hereinafter the thermopile I2 is a self-contained unit which is removably supported on the base Ill so that it can be lifted therefrom and placed over a burner of a conventional stove or other available fuel burning means when this is desirable. The thermoelectric device herein disclosed is especially useful for delivering electricity for operating radio receiving sets or other electric devices in rural areas or other remote places where commercially distributed electric power is not available and is intended for operation on readily available and inexpensive liquid fuel such as kerosene.

The base I0 is here shown as being formed by an annular or ring-shaped fuel tank l3 and a vertically disposed supporting shroud It in which the lower end of the tank is telescopically received. Th tank I: is formed with a laterally outwardly projecting flange or rib l5 intermediate its ends and which limits the extent to which the tank extends into the shroud It. At its lower end the shroud I4 is provided with depending integral legs l6 having feet in the form of cushion or glider elements ll mounted thereon.

The fuel burning means II is located inside or coaxially of the ring-shaped fuel tank of the base In and includes a. substantially cylindrical upright wick tube i9 containing a cylindrical wick 20. The wick tube I9 is firmly attached to the base III as by means of annularly spaced brackets 2| located between the inner wall or periphery of the fuel tank I! and the outer wall of the wick tube. The arcuate spaces extending around the wick tube l9 between the brackets 2| provide passages 22 for a flow of air upwardly through the base for combustion purposes. Air for combustion purposes also flows upwardly through the central passage 23 of the circular wick tube. Fuel from the tank [3 is supplied to the lower end of the wick tube at one or more points therearound as by means of the downwardly and inwardly inclined tubular connection 24.

The fuel burning means ll may also include a flame tube 25 surrounding the upper end of the wick tube l 8 and a dame spreader comprising the perforated annular elements 26a. 23b and 23c located in the air passage 33 of the wick tube adjacent the upper end thereof. The combustion air which flows upwardly through the air passage 23 of the wick tube is delivered to the vicinity of the upper end of the wick tube through the perforations 28 of the flame spreader elements 26a, 26b and 260. Some of the combustion air which flows upwardly through the passages 22 outside of the wick tube passes upwardly through the annular space 29 between the wick tube and the flame tube 25. Some of this outer air stream also passes through perforations 30 provided in the lower portion of the flame tube 25.

The fuel supplied to the wick tube [9 passes upwardly by capillary action through the wick and is burned in the usual way in the form of a more or less sustained flame 3! extending upwardly from the exposed upper end of the wick.

The thermopile l2 comprises an elongated upright tubular member 33 and a relatively large number of thermocouple elements 34 carried by such tubular member and extending through the wall thereof. The thermocouple elements 34 are constructed so as to provide hot" thermocouple junctions 35 at their inner ends which are spaced along and around the inner surface of the tubular member and cold thermocouple junctions 36 at their outer ends which are spaced along and around the outer surface of the tubular member. -The thermopile l2 also includes an annular supporting ring or stand 31 upon which the lower end of the tubular member 33 is supported.

The supporting ring 31 may be constructed as here shown with an outwardly and downwardly extending skirt or shroud 38 which conforms to and harmonizes with the base I 0. The supporting ring also has a downwardly and inwardly extending cylindrical portion 39 which engages and rests on an annular supporting member 40 carried by the wick tube IS. The latter member is disposed around the wick tube and mounted thereon by a spider or bracket structure 4!. As shown in Fig. 1 the fiame tube can be formed as an integral extension of the ring portion 39. When the thermopile i2 is mounted on the base III it is supported by the ring portion 39 resting on the top of the annular member 40. When the thermopile is lifted from the base l0 and placed on a stove top or other supporting surface it is supported by integral depending lugs or feet 42 formedon the shroud 38. The feet 42 are also engageable with the top of the fuel tank I3 to prevent tipping of the thermopile when the latter is supported by the base l0.

As mentioned above the thermopile I 2 is supported on the base In in upright relation in which position the passage 43 through the tubular member 33 forms a stack and combustion chamber extending above the fuel burning means 'H.

When the thermopile is mounted in this relation the heat and combustion gases delivered into the combustion chamber 43 by the flame 3| causes'the hot or inner thermocouple. junctions 35. tobe heated while the outer or cold junctions 36 are cooled by air flowing upwardly around the outside of the thermopile. This temperature differential causes electricity to be generated in the junctions asis well known in this art. The thermocouple junctions are,- of-course, suitably connected in series relationship to each other so that the increments of electric current generated in these couples will be cumulative.

The thermopile I2 is provided with suitable terminals, or pairs oi terminals, 44 and 45 for connecting the generator with the electrical apparatus to be operated. The thermopile is here shown as being provided with a cover 43 at its upper end and a cylindrical protective screen member or name 43 is supported from the cover 46 by the rod 50 and extends downwardly in coaxial relation substantially centrally of the combustion chamber 43 for a substantial portion of the length of the thermopile. The bailie 49 is in the form of a truncated cone having its small end disposed downwardly and serves to direct or distribute the heat and combustion gases so as to cause the same to more effectively heat the hot junctions 35.

An important feature of the present invention is the construction of the thermopile I! so as to enable the same to generate relatively high voltage values in relation to the size of the unit. Theinvention provides a very compact form of construction such that a thermopile capable of producing current and voltage values suiiicient for the direct operation of a radio receiving apparatus embodying a loud speaker can be made of a very small size which will occupy only a small amount of space and which will be manually portable so that it can be easily carried from one point of use to another. Because of this small size and compact construction the thermopile 12 can be heated and operated satisfactorily on the fuel burning means ll shown in the drawings or can be readily lifted from the base l0 and placed over a burner of a conventional cooking stove, lamp, or any other available fuel burning device.

In constructing a thermopile of this compact nature the tubular member 33 is made up of a large number of c'oaxially disposed flat rings 52 formed of asbestos paper or other suitable re fractory and electrically insulating sheet material. The thermocouple elements 34 are disposed in annularly extending groups as shown in the drawings with one such group located between each pair of th refractory rings 52. The thermocouple elements 34 are preferably laid in a layer of suitable refractory cement 53 which serves to connect the adjacent rings 52 together and to hold thethermocouple elements in the desired annularly spaced arrangement.

Another feature of the present invention is the provision in the thermopile I! of a plurality of groups of thermocouple elements for the generation of electric currents of different terminal characteristics. One group of these thermocouple elements consists of the above described elements 34 .which are made of relatively small size wire and a second group comprises similar thermocouple elements 55 which are provided in a relatively smaller number and which are of a relatively heavier material or cross-section. The heavier thermocouple elements 55 are embodied in the thermopile I2 in the same way as the elements 34 and include inner or hot thermocouple junctions 56 spaced along and around the inside of the tubular member 33 and outer or cold thermocouple junctions 51 spaced along and around the outside of the tubular member. When the riorating effect produced by the flame.

The thermoelectric generator which is disclosed herein as one embodiment of the present invention is well suited for use as a source of operating current and potential for radio apparatus such as a radio receiving set embodying a loud speaker. When used for this purpose the group of thermocouple elements 34 constitute the radio and the group of thermocouple elements 55 constitute the source of the A" voltage and current. The values for the 8" and A voltages and current will depend upon the requirements of the corresponding 13 and A" circuits of the. radio apparatus to be operated and the thermocouple elements 34 and 55 are of a suitable construction and are provided in appropriate number to produce these required voltage and current values. In the thermopile 12 as herein disclosed the thermocouple elements 34 and 55 are in the form of paired wires of appropriate diameter or cross-sectional area and are made of dissimilar materials suitable for this purpose such as constantan and Chromel. Since the "B" voltage required by radio sets is usually relatively high in comparison with the A" voltage, the thermocouple elements 34 will usually be provided in very large number as compared with the thermocouple elements 55.

By way of example and in further explanation of the compact construction of the thermopile I 2, it is pointed out that when the generating device is to be used for operating a radio receiving set embodying a loud speaker it is desirable to have the thermocouple elements 34 serve as a source of B voltage and to deliver and maintain a terminal load voltage of approximatelyv 100 volts and a terminal load current of approximately 15 milliamperes. Likewise, it is desirable to have the thermocouple elements 55 serve as a source of A voltage and to deliver and maintain a terminal load voltage of approximately one and one-half volts and a terminal load current of approximately 300 milliamperes. In order to obtain the above mentioned 100-volt terminal potential with the desired load applied, the thermocouple junctions 35 and 36 must be provided in very large number, for example, on the order of 7000 of such junctions. When this number of thermocouple junctions is embodied in a thermopile of the laminated paper and refractory cement construction above described the thermopile 12 can be on the order of six inches in outside diameter and in the neighborhood of six to eight inches in length.

The thermocouple elements 34 and 55 can be made of any material suitable for this use and preferably are in the form of paired wires of dissimilar material such as constantan and Chromel. The wires used for the elements 34 in the example given above may be on the order of .012 of an inch in diameter and the thermocouple elements which are ofrelatively heavier cross-section can 8 be formed of similar wires on the order of .050 of an inch in diameter.

In the generating device illustrated in the drawings the pairof terminals 44 are connected with the thermocouple elements 34 for the delivery of the 8" voltage and the pair of terminals 45 are connected with the thermocouple elements '55 for the delivery of the "A" voltage. The fuel tank i3 is provided with a suitable filling open- 10 ing closed by a screw cap or removable closure 59.

The wick 20 can be raised or lowered in the usual way by conventional adjusting means including a rotatable actuating knob 60. Access can be had to the fuel burning means I l for trimming or replacing the wick and for refilling the fuel tank It by simply lifting the thermopile l2 and removing the same from the base l0.

'F'rom the foregoing description and the accompanying drawings it-will now be readily un- 20 derstood that the present invention provides a the source of the B voltage and current for very useful and compact thermoelectric generating device which can be used in rural areas and other remote places for operating radio apparatus and other electrical devices.

Although the improved thermoelectric generating device has been illustrated and described herein in considerable detail it will be understood, of course, that the invention is not to be regarded as correspondingly limited in scope but is intended to include all changes and modiflca tions coming within the spirit of the invention and the scope of the appended claims.

Having thus described my invention, I claim: 1. In a thermoelectric generator, a base including a heating means and comprising a fuel tank and a burner mounted on the tank and adapted to be supplied with fuel therefrom, a thermopile comprising an upright hollow member and an adapter member connected with the 40 lower end of said hollow member and adapting said thermopile to be supported on said base as a stack for said burner, said hollow member having a wall formed of insulating material and numerous thermocouple elements extending therethrough and including hot and cold junctions located respectively on the inside and outside of said hollow member and spaced along and around the same, said adapter comprising in tegrally connected ring, flange and shroud portions of which said ring portion is an intermediate ring portion with which the lower end of said hollow member is connected and said flange portion is an inner annular flange portion constituting an integral extension of said ring portion and forming a flame tube for said burner cluding a heating means and comprising a fuel tank and a burner mounted on the tank and adapted to be supplied with fuel therefrom, a thermopile comprising an upright hollow member and an adapter member connected with the lower end of said hollow member and adapting said thermopile to be supported on said base as a stack for said burner, said hollow member having a wall formed of insulating material and numerous thermocouple elements extending therethrough andjncluding hot and cold juncarmour? tions located respectively on the inside and outside of said hollow member and spaced along and around the same, said adapter comprising integrally connected ring, flange and shroud portions of which said ring portion is an intermediate ring portion with which the lower end of said hollow member is connected and said flange portion is an inner annular flange portion constituting an integral extension of said ring portion and forming a flame tube for said burner and said shroud portion is a generally flat disk-like annular shroud portion extending laterally outwardly from said ring portion and adapted for supporting engagement with the top of said tank outwardly of said burner, said shroud portion being in plan of substantially the same size and shape as said tank and forming a cover for the tank when the thermopile is in assembled position on said base.

3. In a thermoelectric generator, a base including a heating means and comprising a fuel tank and a burner mounted on the tank and adapted to be supplied with fuel therefrom, a thermopile comprising a hollow member and an adapter member connected with one end of said hollow member and adapting said thermopile to be mounted on said base as a flue for said burner, said hollow member having a wall formed of insulating material and numerous thermocouple elements extending therethrough and including hot and cold junctions located respectively on the inside and outside of said hollow member and spaced along and around the same, said adapter comprising integrally connected ring, flange and shroud portions of which said ring portion is an intermediate ring portion with which said one end of said hollow member is connected and said flange portion is an inner annular flange portion constituting an integral extension of said ring portion and forming a flame tube for said burner and said shroud portion is a generally flat disk-like annular shroud portion extending outwardly from said ring portion and adapted for engagement with the top of said tank outwardly of said burner, said annular,

shroud portion having an angular flange around its outer edge extending in the direction of the axis of said hollow member, and terminal members carried-by such angular flange and electrically connected with said thermocouple elements.

4. In a thermoelectric generator, a base including a heating means and comprising a fuel tank and a burner mounted on the tank and adapted to be supplied with fuel therefrom, a thermopile comprising an upright hollow member and an adapter member connected with the lower end of said hollow member and adapting said thermopile to be supported on said base as a stack for said burner, said hollow member having a wall formed of ring-shaped layers of heat-resistant insulating sheet material and also having thermocouple elements extending through said wall and formed by wires of small diameter lying between adjacent layers of said sheet material and including hot and cold junctions in large number disposed respectively on the inside and outside of said hollow member and spaced along and around the same, said adapter comprising integrally connected ring, flange and shroud portions of which said ring portion is an intermediate ring portion with which the lower end oi said hollow member is connected and said flange tion and forming a flame tube for said burner and said shroud portion is a generally flat disk-like annular shroud portion extending laterally outmardly from said ring portion and adapted for supporting engagement with the top of said tank outwardly of said burner, said thermopile including said adapter member being freely liftable relative to and manually portable apart from said base.

5. In a thermoelectric generator. a base including a fuel tank having a substantially flat wall portion and a burner connected with said tank and adapted to receive fuel therefrom, a thermopile comprising a hollow member and an adapter connected with one end thereof, said hollow member having a wall formed of insulating material and also having thermocouple elements extending through the wall and including hot and cold junctions located respectively on the inside and outside of said hollow member and spaced along and around the same, said adapter forming a support for mounting said thermopile on said base so as to form a flue for said burner and comprising inner and intermediate ring portions and an outer shroud portion, said intermediate ring portion having said one end of said hollow member connected therewith and said inner ring portion being a flange of substantially U -shaped cross-section which engages said burner and defines a flame tube for the same and said outer shroud portion being a generally flat disklike portion extending outwardly from said intermediate ring portion and engaging said flat wall portion of said tank outwardly of said burner.

6. In a thermoelectric generator, a base including a fuel tank having a substantially vertical-axis central opening and a substantially flat top wall portion surrounding said opening and a burner mounted on said tank in substantially coaxial relation to said opening and adapted to receive fuel from the tank, said burner having thereon a shoulder means extending therearound, a thermopile com-prising an upright hollow member and an adapter connected with the lower end thereof, said hollow member having a wall for-med of ring-shaped layers of heat-resistant insulating sheet material and also having thermocouple elements extending through said wall and formed by wires of small diameter lying between adjacent layers of said sheet material and including hot and cold junctions in large number disposed respectively on the inside and outside of said hollow member and spaced along and around the same, said adapter forming a mount adapting said thermopile to stand on said base so as to form a stack for said burner and comprising inner and intermediate ring portions and an outer shroud portion, said intermediate ring portion having the lower end of said hollow member connected thereto and said inner ring portion being a flange of substantially U-shaped cross-section having supporting engagement with the shoulder means of said burner and defining a flame tube for the latter and said outer shroud portion being a generally flat disk-like portion extending outwardly from said intermediate ring v portion and having supporting engagement with said flat top wall portion of said tank, said shroud portion being in plan of substantially the same size and shape as said tank and forming a cover for the top thereof and said shroud portion also having a flange extending in depending relation around its outer edge, and terminal members portion is an inner annular flange portion concarried by such depending flange and connected stituting an integral extension of said ring par.

with said thermocouple elements. said thermopile including said adapter being freely liftable relative to and manually portable apart from said base.

HOWARD J. FINDLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 313,215 Lautensack Mar. 3, 1885 472,261 Gulcher Apr. 5, 1892 1,023,968 .Sharp -1 Apr. 23, 1912 1,519,899 Benner Dec. 16, 1924 1,774,720 Mieville Sept. 2, 1930 2,197,818 Tozier Apr. 23, 1940 2,269,337 Dulaney Jan. 6, 1942 2,362,258 Findley Nov. 7, 1944 2,410,872 Findley Nov. 12, 1946 Number 10 FOREIGN PATENTS Country Date Great Britain of 1891 Great Britain of 1893 Germany Aug. 12, 1893 Great Britain of 1915 Great Britain June 12, 1924 Great Britain May 21, 1925 Great Britain June 24, 1926 Great Britain Jan. 17, 1929 OTHER REFERENCES Kimball et aLz Monthly Weather Review, May 15 1923, page 240.

Milnes catalog (1938) page 2. Copy in Div. 60.

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