US2647505A

US2647505A - Thermoelectric space heater

Info

Publication number: US2647505A
Application number: US295026A
Authority: US
Inventors: Frederick J Bordt; Andrew J Shine
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1952-06-23
Filing date: 1952-06-23
Publication date: 1953-08-04
Anticipated expiration: 1970-08-04

Description

Aug. 4, 1953 F. J. BORDT EIAL THERMOELEC'TRIC SPACE HEATER 6 Sheets-Sheet 1 R as IOI

Filed June 23, 1952 INVENTOR-S. FREDERICKJ.BORDT EL ANDREW J. 5mm.

A Horn y g- 1953 F. J. BORDT ETAL 7 2,647,505

THERMOELECTRIC SPACE HEATER Filed June 25, 1952 FIG.

6 Sheets-Sheet 3 INVENTORS. FREDERICK J. BORDT 32 a ANDREW J. SHINE.

Aug. 4, 1953 F. J. BORDT ETAL 2,647,505

THERMOELECTRIC SPACE HEATER Filed June 25, 1952 v s Sheets-Sheet 4 5 INVENTORS. FRsozmqK 150201 & ANDREW J. SHINE A Home y Aug. 4, 1953 F. J. BORDT EIAL 7 2,647,505

THERMOELECTRIC SPACE HEATER Filed June 23, 1952 s Sheets-Sheet 5 68 65 f 65 INVENTORS.

FRLDERIcKJBo DT 46 3 y &. ANDREW J. Suma 20-" 59 M 24 Affarne) Patented Aug. 4, 1953 THERMOELECTRIC SPACE HEATER Frederick J. Bordt, Averill Park, N. Y., and Andrew J. Shine, Xenia, Ohio, assignors to the United States of America as represented by the Secretary of the Army Application June 23, 1952, Serial No. 295,026

7 Claims.

Our invention relates to heaters of the type embodying a thermoelectric generator.

A primary object of the invention is to provide a space heater having air circulating means operated by a thermoelectric generator, or thermopile, forming a part of the heater.

A further object is to provide an air circulating heater which requires no external source of electrical power to operate the air circulating fans.

A further object is to provide in a heater of the above-mentioned character a novel and simplified thermoelectric generator unit which is easy to assemble, disassemble, and maintain.

A further object is to provide a thermoelectric generator comprising readily removable and replaceable panels or sections.

A further object is to provide in a heater of the above-mentioned character a base or supporting structure which houses and protects the thermoelectric generator panels and bears the weight of the entire heater assembly, in such a manner that the generator panels are subjected to very little strain.

A further object is to provide a space heater in which bulkiness and weight are reduced to a minimum.

A still further object of the invention is to provide a heater of the above-mentioned character- Whieh is highly compact and simple in construction, sturdy and durable, reliable in operation and very easy to assemble and disassemble.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this application, and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a side elevation of a heater embodying our invention,

Figure 2 is an enlarged central vertical longitudinal section through the same, part broken away,

Figure 3 is a further enlarged central vertical section through a thermoelectric generator and burner unit employed in our heater,

Figure 4 is a plan view of the unit shown in Figure 3,

Figure 5 is a horizontal cross section on line 5--5 of Figure 3, with parts omitted,

Figure 6 is a fragmentary vertical section on line 8-B of Figure 5,

Figure '7 is a plan view of an air-circulating fan adapter, part broken away and parts omitted,

Figure 8 is a fragmentary vertical section on line 8-8 of Figure 7,

Figure 9 is a plan view of a heat exchanger employed in our heater,

Figure 10 is an end elevation of an air-circulating fan, parts omitted,

Figure 11 is a plan view of a center cone or flow divider employed in the heater,

Figure 12 is a plan view of a combustion cham'- ber and burner support,

Figure 13 is a side elevation of a thermoelectric generator panel or section removed,

Figure 14 is an edge elevation of the same,

Figure 15 is a horizontal section on line I5'l5 of Figure 13,

Figure 16 is a diagrammatic view showing the electrical connections between an adjacent pair of thermoelectric generator panels and the fan which they operate, and,

Figure 17 is a cross section similar to Figure 15 and illustrating a slight modification of the invention.

In the drawings, where for the purpose of illustration are shown preferred embodiments of our invention, attention is directed first to Figures 1 to 16 inclusive, wherein the numeral 20 designates generally a thermoelectric generator and burner unit, constituting a support for the remainder of the heater. The unit 20 comprises an open-type frame or support which is octagonal as shown in plan, and comprising eight ,equidistantly spaced legs 2|, having upper and lower inclined diverging

portions

22 and 23, and intermediate vertical portions 24, integral therewith. The legs 2| are rigidly connected at their lower ends and above such ends by horizontal

octagonal braces

25 and 26, welded or otherwise rigidly secured thereto. An additional horizontal octagonal brace 21, L-shaped in cross section, is rigidly secured by welding or the like to the inner sides of the legs, adjacent to the lower ends of their vertical portions 24, and brace 2'! also serves as a support for thermoelectric generator panels ,or sections to be described. A top horizontal 00- I tagonal brace 28 is welded or otherwise rigidly secured to the legs 2! at their upper ends. The support thus far described is preferably formed entirely of stainless steel, although other suitable rigid and sufiiciently lightweight material may be employed, if desired.

A combustion chamber and burner support unit 29 is provided, and comprises a downwardly tapering conical sheet metal sleeve or wall 30,

arranged within the lower portion of the main open support, and including a top horizontal octagonal mounting flange 3 I, integral therewith.

The mounting flange 3! is inwardly directed, Figures 3 and 6, and welded or otherwise rigidly secured to the bottom of the L-shaped brace 27, and the entire unit 29 is thus suspended from the brace 2'1. The conical sleeve 30 is lined with cast refractory material 32, as shown, and a depending vertical cylindrical burner support sleeve 33 is rigidly 's'ecu red by welding or the like within the lower end of the conical sleeve 30 and extends for a substantial distance below the same, Figures 2 and 3.

An outer burner sleeve or air duct-*sect'ien- 34 engages telescopically within the support sleeve 33, and is detachably held therein by bolts-35 or the like, with the lower endo'f the sleeve 34 spaced above the bottom of the support, and open for the free admission of air. A tubular, vertical wick-type burner 36 is diseased centrally .row, Figure 1 3. Each thermocouple 49 comprises within the sleeve 34, and rigidly connected therewith by horizontal radial arms or brackets 37. An open annular air pass-age isdefined by the side wall of the burner 36 and the sleeve 34, for the free upward passage of air to support cdmb'ustion. The burner 36 has its top open, and disposed near and slightly below the lower eifd ofthe refractory linedsleeve '3 6'. The burner is filled with Fih'ergias within st, or the like, and 'the bo'ttbin of the burner is connected with a liquid fuel feed line 39, leading to a constant level that valve '40, supplied with .fuel from a suitable tank, not shbwn, by a gravity feed line 49, Figure 2. With this arrangement, a constant fuel Ievei is maintained in the burner 36, and the Fiberglas wick 38 remains saturated with ruer et that it is easy to start the burner in all weather ediiditions.

A thermoelectric generator or "thermopile 4! is housed within the main o'pen support above the unit '29. The thermoelectric generator '4! cbr'npiises 'eigl'i't vertical sections or panels 42 ofcast ceramic material such as J ohns-lVIanv'ille lightweight Firecret'e. The panels 42 have their vetticai edges beveled at 43, so that the eight panels 'in assembly form a continuous octagonal ceiai'fiic Wall, of the vertical leg sections 23, Figures 3 and 5. Each pahe1 I2 is fiat and rett hgurat side 'elevatio'n, as shown. Each sent-1n has embedded therein hear its vertical eagles long vertical act/e1 pins 4'4, which project slightly bey'o'ir'cl the upper and lower ends of the panel. W'hen the panels 42 are placed within the main support, inwardly of the leg sections 2'4, the lower ends 'o'f the panels engage and rest ubon'the L'-"sh'aped octagonal brace "21, and this trace is provided adjacent to its "eigh't corners with pairs of openings '45, Figure '6, receiving the lowei'j'ehd's or "the dowel pins '44. This arrangemerit 'firinly anchors the lower ends of the panels 42 to the -"supporting brace '21, and maintains tl'iefpain'els spaced slightly inwardly or the vet tree; leg portions 24. The panels 42 extend vertically tl'xro'ug'hout substantially the entire le'i'igthsbfthe'leg'sections 24. w

an upper remove-hie octagonal ring 46, L-

shaped in cross-section, rests upon the upper eiid's the panels 12 and is disposed inwardly of the leg sections "2 4. The removable ring 46 is arranged in opposition to the ring. or brace 21, as shown, and is likewise provided near its eight corners with .pairs of openings 41 which receive the upper ends of the vertical dowel pins 44, for 'turther rigidly securing the panels in place within the mainsupport. It will be noted that the arrangement just described renders the individual panels 42 readily removable irom the generator and burner unit 20, and any one. of the panels may be readily removed for servicing a section, 54%01" constantan wire, preferably 20- gage wire, approximately of an inch long; anda section 5205? ZO-gage Chromel wire, ap-

proximately of an inch long. The constantan and Chromel elements -51 and 52 have their ends welded together for forming hot junctions 5'3; embedded within the panels *4: near the centers of the same. "Cold junctions 54 of the thermocouples 8'9 "are spaced beyond the outer faces of the ceramic panels 42', as best shown in Figure 1'5. Heat conductin rods o'r Tim 5 50: stainless steel or the" like are welded to the hot urretithst's, and project beyond the inner faces of the panels E2; The stainless steel rods 55 are fins "5!; of copper or the like are welded to the coldjunctions '54 of the thermocouples, and proje'ct outwardly of the panels '82, as shown. The cop cna'r rods 5% are preferably about one and one 'half inches long, and the panels 42 are preferably about one-half inch thick, although these dimensions may be varied somewhat as desired. The purpose of the stainless steel rods efi is to conduct heat rapidly to the hot junctions of the thermocouples, and the copper rods 56' conduct the heat away from the cold junctions '54 and radiate heat to the air, exteri'drly dithe heater. This "arrangement increases the temperature difiereritial between the hot and cold junctions "53 and 54, 'and renders the thermocouples more efiicient in the generation of electric current. It is to be noted "that the hdtj motions 53, embedded within-the ceramic p'a'n'el fiar'e not "exposed to oxidation, as would be the {case if the hot junctions were disposed beyond the inner side-of the panel 42, for direct contact with the h'ot 'coriibus'tion products. With the arrangement "described above, it is only the stainlesssteel element's which are directly contacted by the hot combustion products. The exposed can junctions 54 "are subjected to "no substantial oxidizing eltect, and the copper ele meh'ts 56 did in 'c'oel ing the same. The thermocouples 49 of each row 50 are electrically connect'e'di'n series, Figure 15, and the several rows 50 of each panel 42 are connected in series by conductors '57, welded to the endmost copper rods i'fi of the rows of thermocouplesas shown. The arrangement is such that the successive rows 50o?thermocouples are-ccnn'ected in series in the "iig-Zag manner shown in Figure 1-3.

A center cone or flow divider '-''58 'is disposed centrallyof "the panels ""42 and spaced inwardly thereof and extends .for the entire vertical lengths of the panels "42, Figure 3. The flow divider 58 forms with "the eigh'tpanels 42 asubs'tantially annular vertical combustion passage 59 forthe upward flow of .the hotgaseous combustion-products generated by the burner 36. The vflow divider 58 has :a bottom conical extension 60, integral therewith and projecting into the combustion chamber defined by the refractory lined sleeve 30, Figure 3. A flame bafile or spreader 6| is rigidly secured to the lower end of the extension 60 and spaced above the open top of the burner 36. The flame spreader 6| causes the flames and hot gaseous combustion products to pass upwardly between the refractory lined sleeve 36 and flow divider 58, and increases the turbulence of the upwardly flowing combustion products and flame. Above the tops of the panels 42, the flow divider 58 has a somewhat enlarged top section or sleeve 62, integral therewith, and having its open top end terminating at the top of the main support including the brace 28. The center cone or fiow divider 58 is rigidly connected with an outer cylindrical adapter sleeve 63, by means of horizontal radial arms 64, Figure 11. A horizontal octagonal flange 65 is rigidly secured to the lower end of the adapter sleeve 63, and rests upon the top of the removable ring 46, Figure 6. The octagonal flange 65 may also have openings formed therein to receive the tops of the dowel pins 44, as shown in Figure 6. The top of the adapter sleeve 63 terminates a substantial distance below the top of the extension 52, and the adapter sleeve 63 is spaced radially outwardly of the extension 62 for forming a continuing annular passage for the upwardly flowing hot combustion products. It may be here noted by way of concluding the description of the thermoelectric generator and burner unit 29, that the stainless steel rods 55 project radially into the annular combustion space 59, and the copper rods 56 extend radially outwardly beyond the vertical leg sections 24, so as to be exposed to the cold air.

A lower heat exchanger and fan adapter 66 is provided, and comprises a central vertical tubular body portion 61 of sheet metal, having a bottom reduced cylindrical extension 68 which tele-' scopes over the adapter sleeve 63. At its top end, the body portion 61 has a reduced cylindrical extension 69 for connection with a heat exchanger to be described. The tubular body portion 61 receives directly the upwardly flowing hot products of combustion from the adapter sleeve 63, and is in direct communication with the annular combustion space 59. The adapter 66 further comprises an inner tubular wall or duct 76 having its top end terminating at the top of the extension 69, and spaced radially inwardly of the extension 69, in concentric relation therewith. The inner duct 19 is integrally connected with four circumferentially equidistantly spaced fresh air elbows ll, having their outer ends rigidly anchored in openings formed in the tubular body portion 61, Figure 8. The elbows serve to rigidly connect the body portion 61 and inner duct 10, in the formation of the integral rigid adapter 66.

Outwardly of the tubular body portion 61, the elbows H carry somewhat enlarged horizontal cylindrical extensions 12, integral therewith, and these extensions 12 are arranged directly over the top brace 28 of the main support, as shown.

Four axial flow air circulating fans 13 are provided, and these fans comprise split cylindrical mounting sleeves or wrappers 14 having telescopic engagement over the extensions 12, and resting directly upon the top brace 28 and adjacent leg sections 22, as shown in Figures 2 and 8. The wrappers 14 have opposed radial flanges 15, integral therewith, secured together by bolts 16, so that the sheet metal wrappers 14 are tight ly clamped about the extensions 72. fairing. ll of wood or thelikeisrigidly mounted A tubular.

within each wrapper I4, and undercut at one end to form a groove receiving the extension 12, Figure 8. A small permanent magnet motor 18 for each fan is provided, and rigidly mounted centrally within the fairing 71, in spaced relation therewith. An air impeller 19 is carried by the armature shaft of each motor 18 for forcing fresh air axially through the fairing 1! and into the adjacent fresh air elbow II. The fresh air from the elbows H then flows upwardly through the duct 19 and into the heat exchanger to be described. The arrangement is such that the entire weight of the adapter 66, fans 13 and all parts of the heater above the adapter 66 is borne by the top brace 28 and leg sections 22, and none of this weight is transmitted to the generator panels 42, which bear only the weight of the sheet metal flow divider 58 and ring 46.

Each fan motor 18 is driven by a pair of the thermoelectric generator panels 42. The current developed by a pair of the panels is suflicient to operate one of the fan motors at maximum efliciency. Wires 88 and BI from each fan motor 18 are connected to one endmost copper rod 56 in the top and bottom rows of thermocouples of an adjacent pair of the panels 42, as shown diagrammatically in Figure 16. A wire 82 connects the endmost copper rods 56 of the opposite endmost rows of thermocouples of the panels 42, Figure 16. With this arrangement, all of the 600 thermocouples of the pair of panels 42 are connected in series with the fan motor 18, and the arrangement is repeated for each fan motor in the same manner indicated in Figure 16. The arrangement whereby a pair of the generator panels 42 operates a single fan 13, independently of the other fans is advantageous, because if one or more of the fans should fail to operate, due to a defect in their motor or in the pair of panels 42, the remaining fans will continue to operate for circulating the heated air.

A vertically elongated heat exchanger 83 is mounted upon the adapter 66 and extends above the same for a substantial distance as shown in Figure 1. This heat exchanger 83 comprises inner and outer

sheet metal ducts

84 and 85, Figure 9, arranged in concentrically spaced relation and defining a generally annular vertical passage 86 for the rising hot combustion products. The outer duct of the heat exchanger is preferably star-shaped as shown in Figure 9 to provide an increased surface for radiating heat. The inner duct 84 is preferably formed to provide a plurality of circumferentially spaced inner and outer radial extensions or

hollow fins

81 and 88, projecting into the bore of the inner duct and into the passage 86, respectively. The

extensions

81 and 88 define narrow

vertical passages

89 and 90 for the hot combustion products and fresh air respectively. This arrangement provides an increased area for the transfer of heat from the hot combustion products in the passage 86 to the fresh air flowing upwardly through the inner duct 84. The

extensions

81 and 88 extend for the entire length of the heat exchanger 83. The heat exchanger 83 is provided at its lower end with inner and outer concentrically spaced cylindrical adapter rings 9| and 92, rigidly secured thereto by welding or the like, and having interfitting telescopic engagement with the cylindrical extensions l0 and 69 of the adapter 66, Figure 8. The heat exchanger 83 is thus bodily mounted upon the adapter 66 and readily removable therefrom. The inner duct 84 is in direct communication with the duct 18, through which the incoming f esh the heat exchanger is in communication with the annular passage between the inner duct. and.

body portionfi'l ofthe adapter 58; Figure 9, and

the rising hot combustion products. mustv enter. the passage 8c and cannot enter the inner heat exchanger duct 8d. The risinghot gases in the passage to transfer most of their heat to the rising fresh air in theinner duct 84.. The star v shaped outer duct 85' will also radiate heat to the surrounding air space to be heated.

An upper adapter and how divider 93; identical with the adapter fifi but.inverted;with-respect to the same, is carried by the top oi-the. heat, exchanger 83. The heat exchanger is provided at its topencl with inner. and outer concentric cylin-.

drical rings M and 95*, rigidly secured thereto and these-rings. engage telescopically with cylindrical extensions 9? and 91: at the lower end of the adapter 93'. The adapter 93. has atubular body portion -28 which communicates with the passage to of the heat exchanger and receives the combustion products after the heat exchange. process has taken place. Elbows 99 of theadapter 93 receivethe heated fresh air from the inner duct 84 of the heat exchanger and these elbowsare connected in theadapter 93' inthe identical manner that the elbows H, previously described. are connected in the adapter The four cl. bows 98. have their discharge ends Hi0. extending radially beyond the body portion fill and horizontally disposed for discharging heated air into the surrounding room or space to'be'heated;

'A conical flue section it; is telescopically mounted upon the top of the adapter 9.3-, asshown,

and a cylindrical chimney M2 is: telescopically mounted upon thefiue section If for conveying away the combustion products, after the. same have been cooled by the action Of the. heat ex changer 83.

As previously stated, the adapter 6ft, fans 113;

and all cf'the. parts above the adapter fifi have their weight borne by the top of the mainframe, including the. brace 28, and the ceramic-genera tor panels 42 donot hear the. weight ofrthese parts. adapter. heat. exchanger &3' and adapter 83 are readily separable, and" may be lifted as a unit from the lower generator and burner unit 2i! shown in Figure 3'; With this arrangement, it is. a very simple matter to remove or replace one or more of the generator panels 4-2, and todo this, itis merely necessary tocremo-ve the loclcingring. to and lift out. the particular panel or panels. 532' and replace thesame by' new panels.

Although-theoper-ation oi the heater is believed to be practically obvious in View of. the. foregoing description, it maybe stated briefly that withtho heater assembled as shown in Figures. 1. and and a constant level of liquid fueluinaint-ained in the burner 36 the wick its-is. ignited, and burning takes place within. the annular combustion space afforded byv the refractory lined sleeve 3.0 and cone t8. A natural updraft ofifreshair to sup port comb ustionenters the lower end of'the. sleeve Gland thehot combustion products upwarch ly and over the stainless steel rods 55. As this occurs, current isdeveloped by the thermoelectric generator panelsdi and the air circulating fans 73 are operated to. force fresh air through the innerduct 84 oil theheat exchanger 8:3.

Simultaneously, the: hot combustion products flow upwardly through the-passage 86 0f the heat exchanger and the transfer of heat from the combustion products to-the-airin the inner duct 8" 84 takes place. Theheatedair passes outwardly from the upper radial elbows 99am. is directed".

oward'the wallsof the room or enclosure. The

residual combustion. products are discharged through the duct section it] and-chimney 111.2.

While we have shown andv describedra simple wick-type burner 36 for the heater, it shouldme understood that any desired type. of updraft burner may be employed.

In Figure 17; we have shown a modified form, of thermoelectric generator panel 42, similarto and interchangeable with the panels, 42, pre viously described. in connectionw-ith the panel 42. the thermocouples 49' have their hot and cold junctions 5t? and 54' embeddedin theocramic material ofythe panel, as shown, and; all of the thermocouple junctions are thus protected from oxidation and other damage which they might be subjected to when projecting outwardly of the sides of the ceramic panels. Each panel as is: preferably provided near its center. and between the hot and coldiunctions. 58 and" 54 with vertical openings or passages I63: Portions of the thermocouple elements, between, thehot and cold junctions extend'through the passages.

Hi3. as shown in Figure 17. If desired, the ends of thepas age it may be closed, adjacent to h upper and lower. endsof the paneldt, and it so closed, the passages its are dead air spaced and; serveto retard or interrupt the flow ofiheat from the hotto the cold junctions, and thus aid-ininoroasing the. temperature differential; between the hot and cold junctions andthe efiiciency of the thermoelectric generator. If desired; the. passages Hi3 may extend. through the top and bottom ends of the panel t2", and air, or some other electrically non-conducting fluid may he. forced through the passa es. This-will further tend to. interrupt the flow of heat between the hot andcold junctions 53 and 5t. As shown in Fla. lire-l7, stainless steel fins. or rods fifi'are welded to the hot junc i n 53 and extend beyond the in..- ner hot side of the panel 42., and copper-rods 56, are also weldedto-the cold junctions 54 and extend beyondthe outer or cold side of: the panel;

' In the form of panel shown in,,Figure ljhtheiinnor-ends of her dsifi and 5B are cast crem bedded inthe ceramic panel- 42, ancl thzis-chro-i vide a very sturdy construction for. the thermoelectric generafter. Except for the modified are rangemcnt shown in Figure 1''? and described above. the oi -11.21542 are identical inconst-ruction with the panels 42 previously described, and shown in e a l in Figures 13 to 15 inclusive. As. previously stated, the panels 42' and 42? are complet ly. intercha eable in the-h ater asseniw b y-shown i Fi ure It is to be understocdthat the forms of the invention herewith shown and described are to betalifinfifi preferred-examples of thesame. and that-various changesin the shapasizeand'aw rangement of parts-may beresorted to,,without. departingfrorn thespiritof the inveutionor the scope of: the subioi.nod" claims.

Hflfilll'lg thus described our invention, we claim:

1. In a thermoelectrichcatenarr upright sup, port includinga pl r l y f circumferential pacedil ss, a subs antially horizontal. poly onal flan e. secured to;the legs a substantial distance above the bottom. or the support and having openings, a plurality of. separateupright thermoelectric' generatorpenels having their lower ends resting uponthe polygonal flange and-having opposed substantially contacting vsiileezlges anddefining a substantially continuous upright panels and provided with openings receiving the upper 'ends of said dowel pins, the top of the support extending above said locking ring for supporting the weight of heater superstructure above the support, and burner means arranged below said substantially horizontal flange for supplying hot combustion products to the passage defined by said panels. I 3K 2. A heater comprising an upright stand;v a plurality of separate substantially fiat thermoelectric generator panels removably mounted upon the stand in upright edge to edge relation and spaced from the top and bottom of the stand and defining a substantially vertical passage through the stand, a fuel burner carried by the stand below said panels and adapted to supply hot combustion products to said passage, a spreader device carried by the stand and extending into the passage defined by the panels for causing the combustion products to pass near the panels while traveling upwardly through said passage, an adapter arranged above the tops of the panels and having a tubular body portion receiving the upwardly moving combustion products, elbows carried by the adapter and extending radially beyond the tubular body portion and resting upon the top of the stand above said panels and supporting the weight of the adapter, fans connected with the elbows for forcing fresh air into the same and electrically connected with the generator panels, an elongated substantially vertical heat exchanger mounted upon said adapter and having passages receiving the fresh air from the elbows and the hot combustion products from the tubular body portion, and a second adapter mounted upon the top of the heat exchanger and having a tubular body portion receiving the combustion products from the heat exchanger and lbows for receiving heated air from the heat exchanger and directing the same substantially horizontally outwardly from the second adapter.

3. A thermoelectric generator unit comprising an upright stand including circumferentially spaced legs, a substantially horizontal polygonal mounting flange secured to the stand above the lower end of the same, burner means secured to the mounting flange and depending therefrom and disposed within the lower portion of the stand, a plurality of substantially vertical ceramic panels resting upon the horizontal polygonal mounting flange and having substantially vertical meeting edges and arranged to form a substantially continuous upright polygonal wall, the meeting edges of the individual panels being beveled, the polygonal mounting flange having openings near its corners, substantially vertical dowel pins carried by th panels near their meeting edges and extending beyond the upper and lower ends of the panels, the lower ends of the dowel pins engaging in said openings of the polygonal flange, a removable polygonal ring resting upon the tops of the panel and having openings near its corners receiving the tops of the dowel pins, a spreader device resting upon said removable ring and extending into th space defined by said panels and having its lower end spaced above said burner means and causing upwardly moving combustion-products to pass close to said panels, and thermocouples embedded in the-panels, the thermocouples of each panel being lectrically connected in series. 1

4. In a thermoelectric generator unit, a support, a generally vertical thermopile panel mounted upon the support, a plurality of rows of thermocouples having their hot and cold junctions embedded within the panel, the thermocouples in the rows and the rows of thermocouples .being connected in series, heat conducting elements secured to the hot junctions of the thermocouples and projecting inwardly of the inner side of the panel, heat conducting elements secured to the cold junctions of the thermocouples and extending outwardly of the outer side of the panel,-

ving through said passages, the passages serving to retard the flow of heat between the hot and cold junctions of the thermocouples, and burner means carried by the support below said panel and adapted to supply hot combustion products which pass upwardly adjacent to the inner side of the panel.

5. In a thermoelectric heater, an upright support including at least three circumferentially spaced legs, a substantially horizontal polygonal flange secured to the legs a substantial distance above the lower ends of the same, at least three separate upright thermoelectric generator panels having their lower ends resting upon the polygonal flange and having opposed substantially contacting side edges and defining a substantially continuous upright polygonal wall forming a substantially vertical passage within the support, a substantially horizontal polygonal locking ring removably mounted upon the upper ends of the panels and serving to prevent separation of said substantially contacting side edges, the top of the support extending above said locking ring, heat transfer means removably mounted upon the top of the support and having its weight borne by the support so that the generator panels are relieved from excess strain, and burner means arranged below said substantially horizontal flange for supplying hot combustion products to the passage defined by the panels.

6. In a thermoelectric heater, an upright support including at least three circumferentially spaced legs, a substantially horizontal polygonal flange secured to the spaced legs a substantial distance above their lower ends, at least three upright thermoelectric generator panels having their lower ends resting upon the polygonal flange and having opposed substantially contacting side edges defining a substantially continuous upright polygonal wall inwardly of said legs, a substantially horizontal polygonal locking ring removably mounted upon the upper ends of the panels and serving to prevent separation of said substantially contacting side edges, the top of the support extending above the locking ring for a substantial distance to support the weight of heat exchange means above the support, a depending tubular combustion chamber wall arranged inwardly of the legs of the support and having its upper end secured to said substantially horizontal polygonal flange i and terminating above the lower end of the support, and burner means dependingly carried by said tubular combustion chamber wall for supplying hot combustion products to the interior of said substantially continuous upright polygonal wall.

7'. In a thei moele etric heater, an up ghtsup- *poit including at least three circufnferiitiaily spaced legs, a substantially hoiizontalpoii'gofial flange secured to the legs a substantiaraistanee above their lower' ends, at East three i lpr i ght r;

thermoelectric generator pane-1's having their lower ends removably mounted upon-manpoweonal flange and having theii upper endetefmi- 'nating a substantial distance below-chaise of the upright support, a substantially horizontal-polygonal locking ring removably mounted upon the upper ends of the panels and serving to feleasabl y secure the same together for fermingasubs tantially continuous upright polygonal "wan, a

spreader device arranged inwardly of the-upright ii I panels and spaced therefrom and defining with the panels a substantially anii'iilai" passage tor receiving upwardly flowing'hot combustion'piouucts a supporting paxt carrying'the spreaderaaevice and resting upon said poly onal lock-mg ring,

means dependingly. secured to the polygemu 'flangeand arranged inwardly of the legs of me support-marine lower end of the support, and Heat truusiermeans removably mounted upon the "-to'p-ofrthessuppertand having their weight borne ==ei1tire1y bythe support so that the panels are free or excessive strain.

FREDERICK J. BORDT. ANDREW J. SHINE.

References Cited in the file of this patent UNITED STATES PATENTS