[1]Patented Oct. 149 1941 2AS9@010 UNITED STATES PATENT OFFICE 2,259,010 "PARATUS FOR COMBUSTION OF FIUIID FU Edwin Taylor, Brooklyn, N. Y., asdguor of twofifths to Wffllam P. Doyle, Summit, N. L Application Mlay 24.1939, Serhd No. 275,462 7 Claims. (CL 60-45) This invention relates to an apparatus for pro- ponent, after utihzation of the mixed gases, is ducing substantiary complete combustion Qf a fluid fuel. More particularly the invention relates to an improved process and app aratus for the buriiing of a gaseous or liquid combustible 5 material commingled with a combustion-4upporting medium to produce 9, heat-conveying pressure fluid medium, which contains products of complete combustion but substantially no prqducts of incomplete combustion, and whicli fUr- lo ther contains substantially all of the heat developed by the substantiary complete combustion of the fuel; and in a particularly advantageous embodiment of the invention to a highly efficient method and means for producing such 15 a heat-conveying pressure fluid medium contatning in addition a volatilized condensable gas and having a temperature substantially less than the combustion temperature, but still containing in a potentially available form substantially aU of 20 the heat units produced during the complete. combustion of the fuel. The heat-conveying pressure fluid medium of the last mentioned preferred embodiment may with particular advantage be employed directly in an iinproyed heat- 25 radiating system or to operate prime movers for the production of power as described And claiined in my co-pending applications for Letter8 Patexit, Serial Nos. 275,464 and 275,465, ffled of even date herewith. The phrase "heat-conveying pressure 30 fluid medium" as used herein and in the claims refers to a gaseous medium which is capable of conveying heat and of being maintained under pressure, which is capable of and may be used for perforining useful work by the release of its 35 heat or by being expanded to a lower pressure, and which further may have associated therewith varying proportions of liquid vapor. Pbr example, if a hydrocarbon fuel is bumed in air in the normal way, the resulting mixture con- 40 tains excess air, nitrogen, carbon dioxide, carbon mono)dde and water vapor. Such a niixture, as do products resulting from the buming of other types of fuel, falls within the designation, "heatconveying pressure fluid medium," as wen as 45 such a mixture to which has been added a vaporized condensable liquid, for example steam. In the latter case the gas or mixture of gases may carry a quantity of water vapor substantially in excess of that re@quired to saturate the gas. 50 Water is the most satisfactory volatile liquid medium, although other Uquids hgving suitable properties may be employed. Since water is one of the products of combustion of most fuels, the cyclic return of a single condensed Uquid com- 55 possible when water is the liquid which is vaporlud and added to the produets of combustion. The present Invention provides a method and apparatus of improved construction adapted to 4ccelerate and complete the combustion of a fluid fuel In a manner and to an extent wl-Ach results in maricedly increased efficiencies, as well as more economic consumption of fuel than has been possible in the methods heretofore employed, and which additionaby provides products of combustion capable of directly Performing useful work to a degree not possible with the previously employed methods. Numerous methods have In the past been proposed for accelerating the combustion of gaseous and licluid fuels and for inducing a more complete combustion of such fuels. For example, the use of catalyzing materials variously disposeci in combustion chambers has been suggested. Such suggesti6ns have included the incorporation of the ca4lyst in the waus of variously shaped fire boxes and combustion ebambers, or its deposition in porous refractory materials through which a gaseous fuel and air can be passed and bumed, or against which a fuel and air mixture can be impinged. Substances most frequently suggested as catalytic agents are freshly deposited and finely divided metals, such as platinum and paliadiuin, or metaric oxides, such as copper, nickel, lead, cobalt, chromium, thorium -and uranium oxides. , The effectiveness of such metals and oxides in promoting and catalyzing surface combustion is well known, but it is equally well known that few if any of such proposed methods have been successful in avoiding the presence of,incompietely, burned materials such as carbon monoxide In the products of combustion. It is the primary object of the present invention to effect the complete combustion of a fluid fuel, thus producing a heat-conveying Pressure fluid medium, containing the substantially complete amount of heat theoretically available from the complete combustion 6f the fuel in a form which is directly available for various useful purposes. I have found that this may be accomplished by injecting and passing, at a pressure in excess of atmospheric pressure, an intimate mixture of a fluid fuel and a combustionsupporting medium, preferably an oxygen-containing ga. s, between a plurality of closely spaced heated contact- surfaces of refractory niaterial. The coinbustion or oxidation of the fuel occurs Pr,'Lmarfly at these contact surfac@6s and results in what Is commonly referred to as "flameless coinbustion.,, The re-
[2]2,259,010 fen-ed to closely spaced surf&M are 30 CODWtuted and disposed In *=rdance vith my lnymtion that their areas hicrease outwardly from the point of injection of the fuel@ at rate substantiau_v in excess of a linear rate. i; such an ar- 5 rangement the mixture of fuel and oxygen-cmtaining gas, which Is rapidly expandim In volume and increasing In speed, is given ample W7 portunity to be In contact with the bmted Surfaces at which the nmjor PorUon of the combus10 tion occurs. By virtue of such a rapid lncrmw outwardly of the ares@s of the contact surfacm the volume of the space between the surfaCM outwardly from the point of Injectim of the fuel, increases at a rate in excess of the rilte of In- is crease in speed and volume iof the coulbusuble .mixture. I[ am thus able to effect the referred to substantiauy complete combustion. L e.. buming to completion the oxidizable constituents of the fuel, by virtue of the Just dwzlbed DOyd 20 arrangement of contact surfaces, as a restfit Of whilch the heated and rapuuy expa dlnff gem and fuel are permitled to be in contact WM the said heated surfaces for a period of time BuMbefore use at a lower temperaum. Ja-that the fuel is being uulized at what Js commonly referred to as its "higher heating viaut"; that * an appreciable part of the heat of combu$Um normsl]ly lost through the llue as latent heat em- 49 ployed in transforming the water of combusum into steam is made use oL Due primarily to failure to achieve substantially complete combustion, however, previously ProPosed system based on this principle have been unsuccesdw. 45 This is in part due to deleterious effects of products of incomplete combustion, such as cazbon monoxide, bydrogen, free carbon and swty ma@- terial, and unbumed entrained fuel. My Invention avoids the formation of Products of incom- 50 plete combustion and provides a method whereby a fuel may be utdiwd at its "higher beaUU9 value." An additional advantage of the Invention resides in the fact that if desired, excess $Lir may be used in the combustion without intr(- 5-1 ducing a loss in heat efficiency. A further important advantage of my Invention, In part due to the completeness of combustion, Is the -gLbsence of corrosion of the varlous surfam with which the products of combustion come in con- 60 tact. improved apparatus, adapted to generate the described heat-conveying Pressure fluid medium in accordance with such a process, is included within the scope of the present Invention, and 65 will be described with reference to the accompanying drawmgs, wlnch wiU serve to Mustmte altemative forms of generator made in accordance with my invention. ]in the drawings, wherein like reference nu- 70 merals indicate corresponding elements: . Figure I is an elevational diagrammatic view. part in elevation and part in section, of an SLPparatus for producing complete combustion In iLccordance with my Invention. 75 rangement does not offer reddance to or build up back pressure agaimt the NW exPsndOn. Or permit any substanual convwuon cunents to be set up whereby products of combusum am . circulated m the -combustim zone to reduce the So availability of the hot contact surfwft to unoxidized materlal. An important advantage of buming a fuel and directly using the products of con2bustion or PUMM 2 Is an axial metion of a generator ad&pw to produce a beat-conveying pressure fhdd medium comprishw a mixture of hot gases and a vol&tmzed condennble Uquid. Figure 3 is an -viol mcum of an altemative form of generator made In &=rdance with my lnvenuan. . Flgure 4 In a diagrammatic representation of the form of gennator niustrated in Flgwe 3, which further Mustrates one mlethod of introducing a volatik liquid Into the products of com-, budim emanating hvm the plurality of combustion =Dm of the genemtor. 7be Procen and appuatus of the invention are effecuft to produce complete combustion of -- different t"m of fluid fuels, provided only that they be gamous or Uquid at normal temPeratures. It to to be understood that the phrase "lWd lUeL" an und herein and in the claims, has xwh AL cmnO"UML AnY 928 or mixture of gam, for example, which is capable of combustion when admixed wUh a gas containing a proportion of oxygen apprqmute to support combustion, may be empkye& pawing them Umugh a volatile liquid n2e&um 35 ine&tm Produced. Pbr example, in burning a zuxfwu of my lnymuon, complete combustion nlay be achieved by the uw of the theoretical anm)unt, of a candmxum-xupporting medium, for exsn=d air. required to effect the oiddation of the components of the fuel In actual practice In the operation of my Process, 11 find It advantageo= to uw a MAU e=ess of ilir, for example 1 to 10%, In order to lower the working temPeraum of the heat-cmveying pressure fluid cient to insure C=Plete oxidatkm Sueb an ar- 25 In buridm a iftuld fuel between the contact cautn Ikuld fuel between contact surfaces of the tn@e dewxibed. a maximum temperature of 3$W P. could be attained. In order to that the contact surfaces would not be harmed bY such a high temperature, an exceft of aPProxtmatelY 10% of air over the theoreticauy required amount was introduced. and the temPUSUM of the resulting :duid medium reduced to &Mroximately 2500- to 2700- P. A sin2PIe and effecuve form of apparatus for carrying out the Process of my Invention is iuustmted In PUme 1. SubstanURBY flat ParaBel Plates of refractory material i aW 2. which n'aY have Incorporated therein A C&ta]Ytic mAteriAl. xuch as for example an oxide of chromium, are backed or supported by Plates 3 and 4 of a'swtable material, such as for exmple heat-resistant steel or other suitable allOY. In the embodiment here ilaustrated, plates 1 and 2 are circular and deffne a narrow flat zone 5. Into which projects through an opening Jn the lUVex contact surface the delivery end of an 'LPProPriatelY suPPorted fuel atomizing head 6, here shown in elev'LUon, of anv aPPropriate design &ftpted to spray an Intimate mixture of a fluid fuel and air radiauy outwardly between the contgct surfw-m. Such a fuel injection device, particularly when a liquid fuel is employed, is Preferably of the tYPe containing an adjustable conical head 7 and WM be described in greater det&U below In connecuon with the apparatus 11IMtrated In PJgure 2. ]In oPer&Ung an apmjltus of the type illustmted. the fuel and air or other combustion supPorUM =@dium. at a pressure in excess of atPressure, are supphad to the atomizer through Inlet PiPes I and I respectively. Thethoroughly admixed. and In the case of a liquid fuel atomlzed nftuare of fuel and air Is sprayed OutwardlY from the delivery end of the atomizer
[3]2,259,010 .3 in a disc-like sheet substantially parallel to the contact surfaces. The mixture Is ignited by a suitable means, suoh as, for example ' a hot wire. T'he mixture of hot gases expanding rapidly with a consequent increase in speed comes into con- 5 tact with the combustion-accelerating surfaces whose areas are Increasing outwardly from the center at an even more rapld rate, and Is completely oxidized at the said surfaces. In the injection of an atomized liquid fuel mixture be- 10 tween such parallel plates, it Is of particular advantage to employ an atomizing fuel head such as is described and claimed in my co-pending application for Letters Patent, Serial No. 275,463, filed of even date herewith, and wherein a por- 15 tion of the air is introduced through ports in the base of the conical head of the atomizer. Such an expedient results in important advantages as hereinafter more fully explained. The expanded heated gases arriving at the periphery of the cir- 20 cular contact surfaces contain carbon dioxide, ' water vapor, and the inert constituents of the combustion-supporting medium, which In the case of air is primarily nitrogen' The gaseous products are free of unoxidized fuel, carbon, or 25 carbon monoxide. I A heat-conveying pressure fluid medium which contains a volatilized condensable liquid, which is substantially free of products of lncomi)lete combustion, and which has a temperat;are lower 30 than the combustion temperature, produced in accordance with a preferred embodiment of my invention is of particular utility. The temperature of such, a fluid medium may readily be controlled to any desired value and is most frequent- 35 ly utilized betw6en about 200' F. and 800' P., depending on the particular use to which it is to be put, for example In heat-radiating systems or In operating prime mover engine assemblies. A generator for producing such a fluid medi- 40 um having a temperature lower than the combustion temperature, but in which substantially aU of the heat is Tetained, will now be described with reference to Flgure 2 of the drawings. As there illustrated, an outer cylindrical wall lO is sup- 4.5 ported by an annular plate I I adjacent the bottom thereof preferably welded thereto. This bottom plate is in turn supgorted by the downcomer pipe 12 whose outer wall is advantageously welded to the inner peripheral edge of the rO bottom annular plate. Mounted on the bottom Dlate 11 and positioned concentrically between ihe down-comer pipe and the outer shell are spaced inverted cup-shaped shells 3 and 4. These may be made of any suitable material capable of withstanding temperature differentials such as,,for example, steel or approortate alloy materials. The annular spaces defined by the outer shell 10 and Intermediate shell 3, Intermediate shell 3 and Inner. shell 4, and inner shell 4 and down-comer pipe 12 are interconnected by means of a series of peripherally spaced openings or ports 13 and 14 adjacent the bottom plate I 1. Eiepending on the desired capacity of the apparatus, additional ports may be provided 6 above the, bottom of the shells, but below the liquid level. These openings permit the free flow of liquid between the various chambers, the common depth in the chambors being determined by an overflow outlet l@ in the exterior cyhndrical 70 wall, to which is attached waste pipe 16. The adjacent opposite walls of the cup-shaped sheils 3 and 4 are cove'red by narrowly spaced linings I and la, and 2 and 2a respectively of refractory ,rnaterial, which define an area 5 similar to that 75 shown In Mgure 1 and an annular cylindrical space 5a. The said refractory material may with advantage have Incorporated therein a combustion-catalyzing substance, for example an oxide of chromium. Releasably attached to the upper edge of outer cylinder I 0 Is a circular plate 17, forming with the cylinder and bottom plate a closed vertical contginer. Through the center of closure plate 17 passes and is secured a fuel inJection device 6. The fuel iweetion device here illustrated Is an atomizek suitable for injecting an atomize ' d mixtnre of oil or other liquid fuel and a combustion-supporting medium such as air Into the combiistion zone 5. The nozzle or delivery end of the atomizer projects through the center of shell 3 and lining plate I' into zone 5 defined by the closely spaced plates I and 2, which provide the contact combustion surfaces. The atomizer should be so positioned with respect to the contact surfaces that the fuel mixture will be sprayed radially dutwardly from the nozzle at an elevation approxiinately eduidistant from the two plates. Extending through the top closure plate 17, the intermediate plate 3 and the contact surface I into the zone 5 Is an ignition mechanism 18 for initially Igniting the fuelair mixture. A hot wire type of.mechanism is preferredparticularly when a liquid fuel Is employed, but ignition may also be effected by means of a jump-spark device. In a generator of this type the fuel is substantially completely burned by the time it has reached the periphery of plates I and. 2. As a precautionary measure, however, I prefer that the annular passage 5a, by means of which the hot gases are removed, be def!Aed by closely spaced concentric cylindrical plates of refractory material In which niay also be incorporated a catalytic matierial. The hot gases are partially cooled by being passed through a continuously replenished standing body of volatile liquid, for example water, in which the plates la and 2a are immersed. The hot gases pass from the annular space 5a through ports 13. The partially cooled gases together with superheated steam pass upwardly through space 19 and are removed from the generator by means of pipe 12. Water is continuousiy supplied. to the generator thtough pipe 20, and may be introduced at ti@e top of the generator through an annular chamber 21 having.downward ' ly dise.harging ooenings 22. The outer cup-shaped she)l 3 is provided around its upper. end with an upwitrdly.extending peripheral flange 23. The water introduced through openings 22 passes across the top of the shell 3 and overflows through a series of peripherally-spaced notches 24. Exteriorly of th6 outer wall of the shell 3 is preferably attached a cylindrical screen '25 for distributing the water overflowing through notches 24 over the surface of the cylinder. The water added to the system in this manner attains an equal level in the various chambers at the bottom of the generator by passing through the peripherally-spaced ports 14 and 13. The common depth of the water in the various annular spaces is determined by an overflow outlet 15 connected with pipe I 6 provided with valve 26. The apparatus may be emptied when not in use through outlet pipe 27. The supply of water to the generator through pipe 20 is automatically regulated by a thermostatie'valve 28, set in accordance with the desired temperature of the gas-steam mixture to be generated. This valve may be secured outside and near the bottom of the outer wall of the generator. The valve may he of any standard construction suitable to
[4]4 2,250,010 effect the desired control of the Inlet water responsively to the temperature of the water in the bottom of the generator. As here Illustrated, the valve comprlses a chamber 29 for a thermostatic fluid connected to a Sylphon bellows 30 and 5 having an attachment extending through the exterior wall IC at a I)oint below the water level in the generator. The Sylphon bellows operates a valve 31 which controis the passage of water from the water inlet pipe to pipe 20. Other types 10 of thermostatic valves may of course be used. The above referred to valve 26 situated in the overflow pipe is a steam trap and may have a structure similar to that of valve 28, except that it opens and permits the pawage of water when 15 exposed to lower temperatures. A Sylphon bellows 30' opens the valve 31' to permit the exit of overflowing water but not the escape of the botter gases. The fuel atomizing head 6. illustrated in Figure 20 2, Is described and claimed in my referred to copending application, Serial No. 275,463, and possesses special advantage when used In connection with the present invention In cases where a liquid fuel is employed. As Illustrated, the atomizer 25 comprises an exteriorly fluted cylinder or rod 32 which is longitudinally and slidably movable in a tubular housing 33. Uquid fuel int-roduced through pipe 8 passes through the grooves of the fluted cylinder 32 to the surface of a conical 30 block 7 depending from the bottom of said fluted member. Air or other combustion-supporting gas is Introduced through connection 9 into an annular chamber 34 defined by the housing 33 and the outer cylindrical housing. Both of these cylin- 35 drical members are bevelled at their lower ends, the inner bevelled member being adapted to form an oil-tight ciosure with cone 7 when the said cone and central mechanism is raised by means of the threaded connection flxed to the upper 40 end of the fluted member. During operation the cone is adjusted to a position with respect to the bevelled edge of cylindrical housing 33 such that a desired amount of oil Is permitted to flow radially outwardly over the surface of the cone. 45 This oil, together with air introduced into annular chamber 34 through pipe 9, passes through the annular beveiled exit 35, and atomizes the oil as it passes therethrough, and particularly as it reaches the sharp peripheral edge of the cone, 5o thus delivering into the combustion chamber an atomized mixture of fuel and combustion-supporting medium. In the particularly advantageous form of atomizer here illustrated, there Is in addition a series of concentrically spaced ports 55 36, which pass through the cone substantially pa,rallel to the axis thereof. Each of these ports has an upwardly extending portion which extends into the air space 34, permitting the liquid' fuel to flow across the surface of the cone with- 60 out entering the ports. In such a device a portion of the air pa@ses through the ports 36 and thence radially outwardly past the surface of the base of the cone, being dlverted In this direction by the opposing piate 2. When this additional ai-r 05 reaches the periphery of the cone and the atomized mixture being discharged therefrom, an increased degree of atomization is produced. The air passing through these ports results In the fu-rther important advantage that the flrst point 70 of contact between the fuel and the contact surface is extended radiaby outwardly, thus preventing the possibility of the deposition of carbon on the coolest portion of the plate substantially directly beneath the atom'7.ing head. A portion of 75 the air paswng through the beveled exit remains above the oil spray, thus delivering the fuel to the contact surfaces between two layers of combustion-supportmg gas. The conical block In the atomizer here Illustrated has an angle of 120* which, with the a@rangement as shown, Is appropriate to produce a flat disc-like sheet of atomlzed fuel and air between the contact surfaces I and 2. A conical angle of approximately 1200 gives best results when such a disc-like sheet is desired.. In generators in which the two closely spaced contact surfaces a&sume a dome-shaped or conical structure, the 6ombustible mixture being injected at the apex, angles somewhat less than 120' are advantageously employed. A conical angle of 90' to 100', as hereinafter more fully explained, produces a globular injection which Is particularly desirable in certain types of generator. Mgure 3 of the drawings illustrates an alternative embodiment of my invention suitable for producing a heat-conveying pressure fluid medium which may also contain a volatile condensable liquid. An apparatus such as that here shown Possesses a greatly increased capacity and may be used to effect a rapid complete combustion of fuel at a rate greater than is possible in an apparatus of the tYPe illustrated by Figure 2. In accordance with this embodiment a plurauty of superimposed coaxially aligned closely spaced substantially bell-shaped surfaces I and 2 provide a plurality of substantially bellshaped passages 5. These contact surfaces are With advantage made of refractory material, having incorporated therein a combustion-catalyzing substance such as for example an oxide of chromium. These surfaces may be supported by blocks 37, spaced at appropriate points in the annular passages between the concentrically placed surfaces. The tops of the bell-shaped surfaces, other than the innermost surface 2, are provided with coaxially aligned openings preferably having progressively smaller diameters approaching the in-ner surface. Such an arrangement of plates and openings deflnes a well, and Particularly when the openings are Progressively smaller a tapering well, which makes possible an equal distribution of thecorabustible mixture in the Passages 5 between the contact surfaces. An intimate nlixture of fuel and a combustion-supporting niedium is injected Into the passages. It will be noted that the areas of'the contact surfaces adjacent the opening at the top increase outwardly therefrom at a rate in excess of a linear rate. Although the rate of increase is not as great as in an apparatus such as that shown in Plgure 1 it is, nevertheless, sufficient to permit the hot gases to expand freely without the creation of a back pressure. 'Me fuel Injection device may be of any suitable type capable of injecting an intimate mixture of the fuel and air Into the space between the openings at the top of the plates. When a liquid fuel is used, an atomizer of the tYPe UIustrated in Figure 2 and more fully in my co-pending application, Serial No. 275,463, wherein the conical block 7 has. an angle of 90', is particularly suitable. . An irnportant advantage of a generator such as that illustrated in Figure 3 is that its use Is not restricted to a vertical position as Mustrated in Figure 3, but it may be Used equ&Uy well In a horizontal position illustrated in Plgure 4. Regardless of its position, the hot products of combustion emerging from the outer ends of the annular passages 5 may be brought In contact
[5],with a volatfle liquid medium to reduce the temperature of the products of combustion and convert a portion of their sensible heat to latent heat in any appropriate manner, for example by spraying the volatfle liquid across the path of the products of combustion. In this way the oxidiving mixture which has been maintained between the plates until complete combustion has been attained is combined with superheated, steam, In the case where water is the volatfle liquid, at any desiredtemperature, said temperature being regulated by the amount of water brought in contact with the hot gases. In Figure 4 is diagrannnatically illustrated one method ofintroducing a liquid, for example water, into the products of complete combustion emanating from between the plates I of a generator of the type illustrated in Flgure 3. In this particular method of operation water supplied through pipe 20 Is sprayed inwardly from a circular ring 38 across the path of the hot products of combustion. - The amount of water, and thus indirectly the temperature of the combined hot gases,and steam, may be controrea by the regulation of a valve 39. In the event that a generator of this type is used in a,vertical position, an arrangement shnilar to that illustrated in Flgure 2 may be employed to pass the hot products of combustion into and through a continuously renewed standing body of water. The oxidation of the fuel according to my invention may be accelerated and perfected to a degree sumcient to yield a gaseous product substantially free of products of incomplete combustion by contact with surfaces of refractory material. I prefer, however, to incorporate in the refractory material a high melting oxidationcatalyzing material such, as for example'an oxide of a heavier metal. I have found that a particularly effective composition is one containing equal parts by weight of kaolin, a hydrated aluminum silicate having a melting point above 31001 IF., and chromic oxide having a softening point above 3800' F. Such a mixture wiR have a melting point above 3500' F. Inasmuch as operating temperatures in generators operated in accordance with my invention are maintained at approximately 25000 F. with 3000' F. a maximum, a mixture such as that described is of particular advantage. My invention, hi)wever, contemplates the use of other catalytic metallic oxides. Certain oxides, for example Fe2O3, having excehent catalytic properties are of limited utility due to their relatively low melting or softening points. The distance between the contact surfaces in the generators of my invention may vary somewhat, the lower limit being deterinined largely by practical considerations such ag the necessity in generators of the type illustrated in Mgures 1 and 2 of arranging the injection mechanism to inject the fuel between the @lates, and the upper limit being such that convection currents are substantially completely eliminated. In practice I have found that a distance of about % to @/8 inch produces the most satisfactory results. The catalytic plates are preferably supported by metallic plates having the same conflguration. Any metal or alloy capable of withstanding high temperatures and pressures is suitabie for this purpose. A high. grade steel or alloy steel wiU in most cases prove satisfactory. The cup-shaped members 3, and 4, in an apparatus such as, is illustrated in Figure 2, are not subjected to as high temperatures aS the corresponding plates In 2,259,010 the apparatus iuustrated In Mgure 1, due to the cooling effect of the water and the mixture of products of combustion and steam which are in contact with the outer surfaces of the said plates. Other heat-resistant alloys, for example the various cobalt alloys, or copper alloys, may also be used for this purpose. The present invention, which has been described In its preferred embodiment as passing 10 the hot products of combustibn into and through a standing body of water, may also be operated by subjecting the hot products of combustion to contact with the water in other ways. For example, as was described with reference to the 15 apparatus of Figure 3, as ieustrated in Mg. 4 the water may be sprayed into the expanding hot gases to accomplish the same purpose. A further method involves the passage of the hot gases into a packed tower, through which is circulated 20 a continuously renewed supply of water. As wiU be apparerit from the above description the heat-conveying pressure fluid medium produced @by a generator of the type shown in Mgure 2 may be regulated to any desired temperature 25 and pressure, these two properties being completely indepeiadent of each other. Thus my process will produce a gas-stream mixture for delivery to a heating system for example, having a pri@ssure of 5 pounds and a temperature 30 which may range from 200' F. to 1000' P. as desired. Similarly the pressure of the gas-steam mixture as delivered may vary over wide limits, for example from I to 10 pounds, as commonly used in heating systems up to several hundred 35 pounds when the mixtiire is to be used to drive air engine. The temperature of the emerging gas-@team mixt&e when a fixed prbportion of air is employed is determined largely by the rate at which wa@ter Is introduced into the generator. 40 The pressure on the other hand is dependent only on the pressure under which the fuel and air are supplied to and taken from the generator. I
