Патент USA US2404676код для вставки
July 23, 1946. L. A. WILLIAMS, JR ‘HEATING APPARATUS ‘ 2,404,676 ' ' Filed Oct. 8, 1942 y ‘ Patented July 23, lhd? 2,404,676 ‘UNITED STATES .ATENT OFFICE 2,404,67 6 HEATING APPARATUS Lynn A. Williams, J12, North?eld, 111., assignor to Stewart-Warner Corporation, Chicago, 111., a corporation of Virginia Application October 8, 1942, Serial No.*461,‘261 1 Claim. (Cl. 126—116) 1 My invention relates to heating apparatus and is more particularly ‘concerned with, but ‘is not limited to, heaters of the internal combustion type 2 The heating apparatus ‘illustrated in the draw ing is an internal combustion type ‘of heater in corporating a typical embodiment of my inven especially adapted for use in aircraft. tion. This heater has a combustion chamber ll] In heaters of the internal combustion type, it 5 located in ‘one end of a ‘tubular heat transfer is ‘common to provide ?nned transfer means for means or heat exchanger l2 and supplying hot transferring heat ‘from ‘the products of combus products of combustion to this heat exchanger. tion to ventilating air directed over the heat A carburetor M has an open end 'I 6 receiving com transfer means by a ram ‘or blower or other suit busti'on air from the heater inlet 13, which is able air circulating means. The heated products 10 adapted to be connected to a ram, blower, or other of combustion are originally directed against the air circulating ‘means. The air entering the car ?ns at one end of the heat transfer means. buretor M is mixed with fuel supplied through a Where the hot products of combustion ?rst come pipe ‘2% having outlet openings 22 located ‘at the in contact-with these ?ns, they are raised to a throat '24 of the carburetor Iii. The combustible temperature which is much in excess of the tema mixture formed in the carburetor I4 is delivered peratures of other portions of the ?ns and par to the combustion chamber l9 through a burner ticularly of that portion adjacent the outlet end tube '28 which is designed to give the combusti of the heater. There is a practical limit to the ble mixture 2. whirling motion as it enters the temperature to which the ?ns can be heated and combustion chamber. since the hottest portions of the ?ns can not be 20 The combustion chamber H] is provided with operated above this temperature limit, the total one or more electrical igniters 28 for initially ig heat output of the heater is materially reduced niting the combustible mixture supplied to this where large portions of these ?ns are operated at chamber. It will be understood by those skilled a temperature materially below the practical in the art that the igniters ‘28 are connected to a limit. ‘ 25 suitable source of electrical energy through a An object of my invention is to provide heating thermostatic switch which is responsive to the apparatus of the internal combustion type in temperature of the heater and serves to discon which local hot spots are eliminated and the heat neat these igniters from their source of current transfer means is heated to substantially uniform when the heater attains normal operating tem temperature throughout its length. 30 perature. A re-igniter 30 is provided to insure Another object of my invention is to provide continued burning of the combustible mixture heating-apparatus wherein the temperature range supplied to the combustion chamber after the between different parts ‘of the heat transfer igniters 2?. have ceased to function. means is reduced to a minimum and stresses and The tubular heat exchanger i2 is made of thin strains caused by great variations in the temper sheet metal, such, for example, as stainless steel, ature of different portions of the heat transfer and has hollow ?ns 32 extending longitudinally means are avoided. thereof. The ends of the ?ns are sealed and the Another object of my invention is to increase interiors of these hollow ?ns constitute gas pas the efficiency of the heating apparatus by main sages 3i for the hot products of combustion sup taining all portions of the heat transfer means 40 plied by the combustion chamber ll! to the inlet at substantially the practical temperature limit. ends of these passages adjacent the combustion Another object of my invention is to provide chamber. The hollow ?ns 32 are provided with new and improved heating apparatus which is bases .35 and portions of these bases surround extremely light in weight and ‘compact and has a and closely engage the sheet metal shell 38 of a high heat output. 45 muliler it which is ?lled with sound absorbing Another object of my invention is to provide material such as glass wool or stainless steel new and improved heat transfer means. wool. The shell 38 is provided with a plurality Other object and advantages will become ap of openings ‘M which form ~acoustic couplings be parent as the description proceeds. tween the interior of the mulller shell and the gas In the drawing: passages 34, whereby sound may enter the mu?ler Fig. l is a view showing a longitudinal section shell and be absorbed by the glass wool or other through heating apparatus embodying my inven tion; and material therein. . The mu?‘ler 40 has a tapered end 46 which is Fig. 2 is a transverse, sectional view taken on covered by a rounded cap or nose 48 located ad the line 2-2 of Fig. 1 and showing part of my 55 jacent the combustion chamber ID. A space 50 novel heat transfer means in enlarged section. located between the cap ‘48 and the adjacent end 4 3 ing has a cylindrical part which closely ' sur- of the muffler shell serves as a heat insulator rounds the heat exchanger [2 and cooperates therewith to form ventilating air passages be to protect the sound absorbing material from the more intense heat created in the combustion chamber. The cap 48 is preferably of heat re tween and around the hollow ?ns 32. The ven tilating air ?owing through these passages ab sisting metal and is welded or otherwise attached to the end of the muffler shell. ,The hot products of combustion formed in the combustion chamber 18 flow from the open left sorbs heat from the hollow ?ns 32 and the aux iliary ?ns 54 and the heated ventilating air is discharged from the lefthand end of the casing 66 into the air craft cabin, or other space to be hand end of this chamber around the tapered end of the mu?ier and into the gas passages 34 in the 10 heated, or into a system of ducts for conducting this heated air to variously located outlets. hollow ?ns. The annular wall 52 of the combus When the heater is in operation, the auxiliary tion chamber is illustrated as being spaced from ?ns 54 conduct heat away from the adjacent por the bases of the ?ns and this arrangement and tions of the bases 36 of the hollow ?ns with su?i the tapered end of the mu?ier permit these gases to ?rst contact the heat exchanger l2 over an cient rapidity to maintain these portions of the ' appreciable portion of its length. By thus creat bases at substantially the same temperature as other portions of the heat exchanger. In other words, the entire heat exchanger is maintained at substantially the same temperature during heater operation. Since this temperature may be the practical temperature limit at which the heat exchanger can be maintained, the heat output of my novel heater may be'the maximum pos sible for the materials used. This provides a light r and compact heater of high output and wherein ing a relatively large area over which the hot products of combustion ?rst establish contact with the heat exchanger, the creation of intense v1y heated local hot spots in the heat exchanger, and more particularly inthe bases of the hollow ‘?ns, is avoided. Even with this arrangement, .however, those portions of the ?n bases with which the hot products of combustion ?rst come in contact, would be heated to a higher ‘temper ature than the rest of the heat exchanger, un durability and long life are insured by the ab sence of stresses and strainsresulting from sub stantial temperature variations in the heat ex ‘ less special means is provided to carry off more rapidly heat from these portions of the ?nned bases. My invention lies in the provision of such special means. changer. Such a heater isrparti'cularly adapted for, but not limited to, use in aircraft. ' My novel means for reducing the temperature ‘ 'While my novel heat exchanger with its auxil iary ?ns at one end thereof is particularly adapt; of these portions of the ?n bases which are ?rst contacted by the hot products of combustion is ed for use in a heater of the internal combustion best illustrated in Fig, 2. This means comprises type, this heat exchanger is not limited to such] the provision of auxiliary fins‘ 5!! located‘ between the hollow ?ns 32 and extending only through . use. Under some circumstances, ‘my new and improved heat exchanger is particularly advan "out that portion of the heat exchanger which is ?rst contacted by the hot products of combustion from the combustion chamber It. The auxiliary ?ns 54 are illustrated as being formed of sheet . metal and as being of T-shape in cross section. The heads 55 of the ?ns 54 extend lengthwise tageous in connection with exhaust heaters where . the hot exhaust gases are delivered to one end of the heat exchanger. and tend to raise the tem perature of the ?n bases adjacent this end above the temperature of other portions of the heat ex changer. My invention is also not limited to the details herein shown and described, but may as . of the bases 35 of the hollow ?ns and are se . curedlthereto by welding,rsilver soldering, or in. surnenumerous other forms and my invention is any other suitable manner so that theheads 55 i, -to be construed as including all variations and are in intimate, heat-conducting contact with modi?cations falling within the scope of the ap these bases 36. Large quantities of heat absorbed pended claim. * by the bases 36 of the hollow ?ns are transmitted ' to the auxiliary ?ns 54, which dissipate this heat to the ventilating air and thus reduce the operat- , claim: a A heating ‘apparatus of the class described, comprising in combination a heat exchange mem . ing temperature of the ?n bases where these Ibases are ?rst contacted by the hot products of combustion. The auxiliary ?ns 513 may be made ‘of any suitable length, but I have found that en-_ I ber formed of thin sheet metal and having deep ‘ longitudinally extending corrugations in its w .1 providing outwardly projecting hollow ?ns In spaced relation to each other about said member, Vmeans forming a combustion chamber at the rear end of said heat exchange member adapted to supply hot gases to the interior of said member and said ?ns, a backwardly tapered mui?er in said heat exchange member serving to close the inner faces of the ?ns through a substantial por tion of their length at their forward portions, tirely satisfactory results are obtained where ' these auxiliary ?ns are substantially co-extensive with that portion of the heat exchanger which is ?rst contacted by the hot products of combus tion. The lefthand end of the heat exchanger [2 is closed by a plate 58 supporting an outlet ?tting 50. The hot products of combustion give up their outwardly projecting auxiliary ?ns in the form :heat to the heat exchanger 12, as they ?ow of Solid metal plates secured in position in the. lengthwise of the passages 34 in the hollow ?ns,. and the cooled gases then flow from the lefthand 65 spaces between said ?ns by means of ?ange por tions turned at an angle to the ?ns and in snug ends of the passages 34 into an outlet chamber engagement with the outer faces of the wall por 62 ‘formed between the plate 58 andthe adja tions between said ?rst named ?ns and extending cent‘ end of the muffler 40. These gases are dis charged through the outlet ?tting 60 and pass ‘longitudinally adjacent the tapered portion of to atmosphere through any suitable exhaust pipe 70 said muffler, and means for feeding ventilating air attached to the threaded end 64 of the'outlet through the spaces between said ?ns for heating ?tting. said ventilating air and for protecting the ?ns - The heat transfer means l2, carburetor I4, and ‘ adjacent parts are enclosed within a sheet metal casing 66 connected to the air inlet I8. The cas from burning out. 75 > LYNN A. WILLIAMS, JR.