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@ct 8, ‘R946. zmwm e. E. MUMMA WARM AIR FURNACE Filed April 28, 1941 ' 5 Sheets-Sheet 1 Wat. , , 2,408,991 G. E. MUMMA ’ WARM AIR FURNACE 5 Sheets-Sheet 2 Filed April 28, 1941 55/ / Z5 55 25 BY Gear . QZMMZ/Im ' Oct. 8, 1946. ' e. a. MUMMA r 2,408,991 WARM AIR FURNACE Filed April 28, '1941 5 Sheets-Sheet 3‘ Oct. 8, 1946. ' s. E; MUMMA 2,408,991 ' WARM AIR FURNACE Filed April 28, 1941 5 Sheets-Sheet 4 J“ilI[-‘.zlQi-fM.lT INVENTOR. 600/’ 2/1- , w G. E. MUM-MA WARM AIR FURNACE 2,408,991 ' Filed April 28, 1941 . 1% 5 Sheets-Sheet 5 I ' o 4.9 - Patented Oct. 8, 1946 ‘ 2,408,991 UNITED STATES PATENT OFFICE 2,408,991 WARM AIR FURNACE George E. Mumma, Winnetka, Ill., assignor to Sears, Roebuck and 00., Chicago, 111., a cor poration of New York Application April 28, 1941, Serial No. 390,713 2 Claims. (Cl. 126—99) 1 2 Fig. 16 is an enlarged fragmentary perspective detail of a juncture ring shown in Fig. 12; My invention relates to warm air heaters, and has to do more particularly with a sectional heat Fig. 17 is a similar view of a side wall liner ing device. I realize that sectional heating devices have heretofore been suggested, as shown for example forming a part of my invention; and Fig. 18 is a similar view of the rear cover shown in Fig. 14 and showing detached from the cover a liner associated therewith. It will be understood that the device shown in the drawings may be constructed either as a hot in Richardson Patent 1,072,499, September 3,. 1913; Allington 1,723,716, August 6, 1929; West wick 2,157,643, May 9, 1939, and others. However, I have evolved what appears to be a air furnace or as a circulating stove, the differ novel construction for a device of the type referred 1O ence being principally one of size and proportion, to, which I believe to have certain marked ad in either event being surrounded by a casing vantages over any device of this type heretofore through which air circulates in a manner well known. known in the art. The drawings show only the Particular objects of my invention are to pro heating element itself which serves to transfer ’ vide a sectional warm air heater which may be 15 heat to the air circulated around it, the outer constructed either as a furnace or as a circulating shell or casing being omitted for convenience of illustration. stove, which is especially simple in design, which is economical to fabricate, which provides in creased heat exchange efficiency, and which, in general, is thoroughly satisfactory for the pur The numeral iii indicates a front cover section which may conveniently be provided with a ?re door II for the introduction of solid fuel, and a suitable forward extension [2 may be provided for this purpose, if desired (Fig. 3). It will be understood, however, that my invention is not limited to a hand stoking device but may, if poses desired. Other objects and advantages will, no doubt, suggest themselves to those skilled in the art as the description proceeds. Referring now to the drawings forming a part desired, be adapted for automatic stoking and of this speci?cation and illustrating a preferred embodiment of my invention: even for gaseous and liquid fuels. The front cover section may also be provided with an extension 15 which is provided with a door 16 for the ash ' Fig. 1 is a front elevation, partly in section, of a heating device embodying my invention; Fig. 2 is a detail elevation of the lower extremity pit. Suitable draft opening is provided for, as at H, with a closure therefor, such as damper l8 of the shaker handle; Fig. 3 is a sectional view taken substantially along the line 3-3 of Fig. 1; Fig. 4 is a fragmentary perspective view show ing an end of a grate bar section; Fig. 5 is a perspective view of a grate shaker arm; Fig. 6 is a vertical sectional view of an inter mediate section along the line 6-6 of Fig. 3; Figs. 7 and 8 are sectional views taken sub stantially along the lines 'l——‘| and 8-—8, respec tively, of Fig. 3; A rear cover sectionz? is also provided (Fig. 14). 35 . Intermediate the front section 10 and rear sec tion 20, I provide a plurality of duplicate sec tions 25. Any desired number of these inter mediate sections may be employed, depending upon the heating capacity desired. Referring to Figs. 6 and 15, it will be seen that each of the intermediate sections includes a vertically elon gated and laterally restricted chamber 26 which includes the ash pit portion 21, fire box portion Fig. 9 is a plan view of a front closure element for the foremost exhaust ?ue section; pivoted on pintles I9. , Fig. 10 is an elevational view of the front cover; Fig. 11 is a plan view of a juncture ring; Fig. 12 is an elevational view of a juncture ele 28, and a restricted gas portion 29, Fig. 6. The 45 shape as illustrated in Fig. 6 is found very advan tageous in promoting rapid travel of combustion gases and efficient contact thereof with the sur‘ faces. Improved combustion is also facilitated by this shape. There is also effected a saving of ment forming a part of the main ?re box; Fig. 13 is a plan view of the rear ?ue connecting 50 metal. Above the ?re box portion 28 it will be Fig. 14 is an elevation of the rear closure ele seen that the section becomes extended or ?ared in width and narrower from front to rear, to pro ment for the ?re box; Fig. 15 is an elevational view of one of the inter mediate sections shown in Fig. 6; 55 ferred to generally by the numeral 3% (Fig. '7). element; vide a scutiform pouch 30 for gaseous products of combustion, this upper pouch portion being re 2,408,991 4 Elongated ports 3| permit the passage of gases 6| engaging behind the hooks 58. These liners of combustion from the ?re box 28 into the ?ared 6B are formed of ceramic material, a heat re section 30, baffles 33 being provided in order to sistant alloy or other suitable heat resistant ma force these gases into contact with the outer walls terial to protect the device from the very hot gases of the section. The gases flow out of the enlarged In of combustion immediately above the fire bed. A section 39 through slots 35 into a manifold 35, suitable liner 62 is provided for the rear section passing out through a flue extension Iii (Fig. 3) 29, which has formed on the inside thereof a suit in the rear of the device. ' able socket-like element 63 (Fig. 18) for retain The ?ared section 35 is provided with an arcuate ' ing the former, and a similar liner 64 (Fig. 8) is slot 39 below the manifold 35, which permits attached to the front cover section is above the transverse passage of air through the flared sec grate. It will be noted from Fig. 8 that the liners tion 3!}, providing a large surface for heat ex~ 60, B2 and 64 are vertically corrugated and are change. t will be noted that the slots 35) follow spaced from the inner walls of the furnace. These the contour of the top of the combustion ch. .. liners thus serve not only to protect the walls from ber, thus providing a heat exchange surface at th overheating and possible disintegration but also hottest portion of the chamber; also that the slot provide vertical passages whereby air streams may is sloped so as to inhibit collection of dust. soot and fly ash, which would act as an insulator. Thus, it will be seen that each ?ared pouch section serves as a heat exchange ?n. Not only is a very great surface provided by the arrange ment shown, but also, by narrowing the flared sections, the velocity of the gases is increased, adding further to efficiency. Each flared section 30 is provided on each side thereof with openings which are closed by means flow from the lower portion of the furnace, heated, and continue into the upper portion, thus pro viding preheated secondary air for combustion of the gases distilled from the fuel bed, thus greatly adding to the efficiency of the device. The liners may, if desired, extend below the grate, in which case they will receive air rising from the ash pit along the sides of the grate and discharge it at the top of the liners. Juncture rings 65 (Figs. 3 and 11) similar in cross section and in function to the elements 55 of doors 4!), suitable packing, such as asbestos rope, being provided around the edges of the are provided in the upper or manifold portion of doors. These doors are provided with ‘nook-like the device, circular ribs 66 being formed on the portions 4! (Fig. 6) which engage studs 42 or ?ared portion 36 of intermediate sections 25 to the like formed on the inside wall of the ?ared seat in said rings 65. portion 30. A lip 43 or the like may be provided The grate is likewise formed in a plurality of on the outside of the doors 43 whereby they may sections 70, one grate section being provided for be engaged by a suitable tool and removed for each of the intermediate sections 25. As best seen cleaning out any soot, fly ash, or the like which in Fig. 4, each grate bar has formed on each end might collect in the passages of flared portion thereof a U-shaped outwardly extending hanger 39. However, it should be noted that by reason flange ‘H which is rotatably seated on a bearing of the downwardly sloping walls 45 of the por stud 12 extending inwardly from the wall of the tion 3!], which slope down preferably at an angle section 25 and preferably formed integrally there of at least 45°, fly ash will tend to drop by gravity 40 with (Fig. 6). Each grate section 19 is thus sup out of these passages and hence will not readily ported at each end thereof. At one end shaking collect so as to reduce heat exchange efficiency. means is provided in the form of a shaker arm Such collection is also minimized by the turbu 73 (Figs. 3 and 5) which has a stirrup-like por lence currents produced by the bailles and by the tion 15 encompassing the U-?ange ‘H of the grate. restricted width of the ?ared portion 38, produc ing high velocity of gases. Hence, cleaning will be only infrequently required. The manifold 36 is closed at the front by means of a plate 48 (Figs. 1, 3 and 9) which is provided with cars 49, 49', through which extend tie rods 50 and 50’, the front cover It! also having an upstanding ear £59" opposing car 49'. Similar ears 49a, 492). are provided on the ?ue section 37 through which the tie rods pass, while the rear cover section 25 has an car 490 opposing ear 491‘). Additional tie rods 5| are provided on each side 'I'he stirrup 15 is made only slightly larger than the ?ange "H so as to form a relatively snug ?t therewith, whereby rotation of each shaker arm rotates its corresponding grate section with sub stantially no play. Each shaker arm has a de pending bar 16 which carries adjacent its free end a stud 11 which is journalled in an eye portion ‘E8 of a grate connecting bar 80 (Fig. 3). The bar 80 is suitably connected to a shaker lever 82 dis posed in a convenient position to one side of the CLI .Vi front cover section I0, and journalled thereto as of the portion 28, suitable cars 52 being provided at 83', and having a depending arm 84 pivotally secured to the connecting bar 89 as at 85. thereat on the front cover section It] and rear cover section 20. Of course, the tie rods may be tionally advantageous arrangement. disposed at other suitable points, such as inside the furnace in addition to or instead of at the points shown. Between adjacent sections 25 are provided junc ture or sealing sections 55 (Figs. 3, 7, 8, 12 and 16). These sections 55 are of H cross section, each having a groove 56, Fig. 16, on each side thereof which receives the edge of the adjacent intermediate section 25, rope asbestos or other suitable gasket material being disposed in the grooves to provide a gas tight joint. On the inner ?ange of each of the juncture sections 55 I provide a cut out portion 5'! adjacent which is an upstanding hook-like portion 58 for It will be seen that I have provided an excep Substan tially the entire organization may be cast, thus contributing greatly to low cost. A heater may be made of any desired capacity merely by pro viding the desired number of sections 25 and junc ture elements. After a unit has been set up, if 7 any change in capacity is desired, it is only neces sary to remove the tie rods and add or remove the necessary number of intermediate sections and juncture elements. Assembly and demount ing is done very rapidly and conveniently, in - view of the interlocking arrangement and tie rods. The front and rear sections may be inter changed without disturbing the rest of the or ganization. retaining liners 69 (Figs. 3, 6, 8 and 17), the heat efficiency is also found to be greater latter being provided with laterally extending ears 75 as The compared with similar devices heretofore 2,408,991 , known. Thus, I have found from tests that by reason of the large amount of heat exchange sur face provided, according to my design, a saving of metal amounting to as high as 35 per cent may be e?ected for a given heat output, as compared with standard cast iron warm air furnaces. Metal may be saved by reason of the fact that much thinner walled sections may be used than 6 fording accessibility to the interior of said pouch, coextensive opposite walls joining with the several of said narrower pouch de?ning edge-wall por tions to form an enclosure constituting said scutiform pouch, wall means de?ning an arched transverse communication opening through said coextensive walls and serving as a heat exchange passageway, said coextensive opposite walls hav ing also a circular flue duct over said arched view of the fact that, according to my invention, 10 opening communicating with the interior of said scutiform pouch, and fine deflecting ?ns extend the products of combustion are carried away at ing from said wall means and continuing the such a great velocity that local overheating is arched curvature of said opening within said avoided. Where such heat would be at all likely pouch for the purpose of deflecting ?ue gases to occur, as adjacent the ?re bed, protective is possible with previously known structures, in liners are attached. which rise from said ?re chamber into heat ex Various modi?cations may suggest them selves to those skilled in the art Without depart ing from the spirit of my invention, and, hence, I do not wish to be restricted to the speci?c form edge-wall portions. changing lapping engagement with said ?aring 2. A section furnace component for tandem multiple assembly comprising an integral casting shown or uses mentioned, except to the extent 20 having ?re chamber and ash pit de?ning wall sec indicated in the appended claims. I claim: 1. In a heater apparatus, a plurality of similar component sections of which each comprises an integral casting designed for tandem assembly, each of said component sections including a low ermost portion having a horizontal bottom edge wall and a pair of opposite side edge-walls, said bottom and side edge-walls pro?ling correspond ingly and proportionally an ash pit chamber and a fire chamber and including a junction-de?ning edging for abutment with the corresponding edging of adjacent component sections, reverse curve portions merging into the upper extremity of said side edge-walls and extending inwardly to form a Slight constriction thereat with edging flanges meeting centrally and de?ning an arch, relatively narrower side edge-wall portions merg ing with said reverse curve portions and ?aring outwardly to extend beyond said opposite side edge-wall of said lowermost portion, thence ex tending vertically, and thereafter joining‘ with a horizontal plane edge-wall portion to accordingly de?ne the perimeter of a scutiform pouch, the vertical portions of said relatively narrower edge wall having opposite cleanout openings for af tions at opposite sides and bottom of substan tially rectangular outline, said wall sections curv ing at the upper extremity of the sides inwardly into a constriction and arch de?ning outline, rel atively narrower edge-wall portions merging with said wall section at the region of said constriction and angling outwardly thence vertically and join ing with a horizontal-plane narrower edge-wall portion to accordingly de?ne the perimeter of a scutiiorm pouch, coextensive opposite walls joining with said narrower edge-wall portions to enclose said scutiform pouch, wall means extend transversely through said coextensive oppo site walls and de?ning an arched transverse com munication opening therethrough for serving as a heat exchange passageway, said opposite walls also having a circular flue duct opening over said arched opening by communicating with said pouch, and flue gas deflecting means extending within said pouch and abutting opposite ends of said arched opening wall means to effect wiping contactual engagement outwardly of flue gases rising within said pouch from the region of said ?re chamber. GEORGE E. lVIUlVEMA.