US2483737A

US2483737A - Internal-combustion burner for heaters

Info

Publication number: US2483737A
Application number: US494155A
Authority: US
Inventors: William C Parrish
Original assignee: Stewart Warner Corp
Current assignee: Stewart Warner Corp
Priority date: 1943-07-10
Filing date: 1943-07-10
Publication date: 1949-10-04
Anticipated expiration: 1966-10-04

Description

Oct; 4, 1949. w. c. PARRISH mwmmucomausnon BURNER FOR HEATERS 5 sheets-sheet 1 Filed July 10, 1943 alicr'r ngys Oct. 4, 1949. w. c. PARRISH INTERNALCOMBUSTION BURNER FOR HEATERS Sheets-*Sheet 2 Filed July 10', 1943 Mb) mam;- M 1,2 x22,- I eas,

Oct. 4, 1949. w. c. PARRISH 2,483,737

INTERNAL-COMBUSTION BURNER FOR HEATERS Filed July 10, 1943 5 Sheets-Sheet 3 Oct. 4, 1949. w, c, p s 2,483,737

INTERNAL-COMBUSTION BURNER FOR HEATERS Filed July 10, 1943 5 Sheets-Sheet 4 4 w. 6. PAR RISH INTERNAL-COMBUSTION BURNER FOR HEATERS I 5 Sheets-Sheet 5 Filed July 10, 1943 Patented oct Ql m' mmauat-oomnus'rron nunm-m roa mums wllliamc.l'arrish,llrkme,m.,lsllgnorto Stewart-Warner corporation, Chicago, 111., a-

eorpcraticn of Virginia Application July 10. 104:. Serial No. 494.155

' 3 Claims. (01. iss-zs) My invention relates to internal combustion heaters, and is more particularly concerned with. but. is not limited to, internal combustion heaters oi the kind used in aircraft for heating the cabins and other spaces,

An object oi my.invention is to provide a new and improved internal combustion heater, wherein the combustion of the fuel is more complete and eil'icient than in the heaters of the prior art.

Another object oi my invention is to provide a new and improved internal combustion heater, wherein the fuel is sprayed into the combustion chamber in a direction counter to the incoming combustion air to insure thorough vaporization of the fuel and thorough admixture of the vaporized fuel and air.

Another object of my invention is to provide an internal combustion heater having a new and.

improved combustion chamber.

Another object of my invention is to provide an internal combustion heater-wherein the combustion chamber is specially designed to promote thorough intermixins and combustion oi the burning gases. 7

Another object of my invention is to provide an internal combustion heater having a novel design of combustion chamber which shortens the length of the flame created by. the burning gases.

Another object is to provide an internal combustion heater having a novel combustion chamher which prevents the flame leaving the combustion chamber from concentrating on any partlcular part of the heat exchanger.

Another object of myinvention is to provide a new and improved internal combustion heater which may be operated more eihciently to give oil. difierent quantities of heat.

Another object of my invention is to provide a new and improvedinternal combustion heater wherein the ventilating air may iiow through the heater in'either direction.

Another object of myinventlon is to provide a new and improved'internal combustion heater which is capable of operating with nozzle supplied iuel under lower. fuel pressures than were heretofore deemed necessary.

Other objects and advantages'will become apparent as the'description proceeds.

In the drawings:

Fig. 1 is a longitudinal sect on hrwsh art of an internal combustion heater embodying one form of my invention;

Fig. 1A is a sectional'view through the fuel supply nozzle, and is taken on the line Ia-la of Fig l;

Fig. 2 is a view similar to Fig. 1, but showing a modified form of my invention;

Fig. 3 is a longitudinal sectional view through a third form of internal combustion heater embodying my invention. In this figure, the carburetor and related connections to the heater are diagrammaticaily' shown in side elevation.

Fig. 4 is-a transverse section taken on the line 4-4 of Fig. 3; a

Fig. 5 is a partial transverse section taken on the line 5 -5 of Fig. 3; and

Fig. 6 is a partial longitudinal section through the fourth form of internal combustion heater embodying my invention.

The heater shown in Fig. 1 has a casing in provided with an inlet i2 adapted to be connected to a ram, blower, or any other suitable source of ventilating air. The right-hand end of the casing is not shown but is designed to discharge the heated ventilating air either directly into a cabin or otherspace to be heated, or into a duct having one or more outlets at any desired location or locations in one or more spaces requiring heat. A heat exchanger indicated generally by reference numeral II, is located in the casing l0 and is supplied with hot products of combustion by a combustion chamber l6 attached in any suitable manner to the left-hand end of the heat exchanger. The particular heat exchanger indicated in Fig. 1 is shown morev fully as part of the embodiment of Fig. 3, and will be discussed in greater detail in the discussion of the modification of that figure.

The combustion chamber It has a cylindrical sidewall l8 preferably formed of sheet metal or other suitable material, and an end wall 20 welded or otherwise suitably secured to the cylindrical side wall It. An important feature of my invention lies in the particular configuration of the end wall 20. This end wall has a central inward projection 22 which merges in a curved surface with an annular groove 24 which is semi-circular in cross section, as clearly shown in Fig. l 01 the drawings. Fuel is supplied to the combustion chamber through a nomle 26 which is threadassays? a 3 ed into a ring 28 welded or otherwise suitably secured to the central projection of the end wall 20. i

\ 4 airisdeflected away fromthetransversely curved The nozzle 26 is connected to a fuel supplypipe 30 which receives gasoline or other liquid fuel under pressure from a fuel pump or any other suitable source. In accordance with usual practice, suitable means may be provided to vary the rate of fuel delivery from the nozzle orifice 36 by varyingthe pressure in the fuel pipe 30, and thus vary the heat output of the heater. The nozzle 25 has a spinner 32 provided with tangentially arranged fuel delivery passages ll, which give the fuel a whirling motion so that it emerges from the nozzle orifice 36 in the form of a fine coneshaped spray. The dimensions of the structural I parts of the nozzle may be varied to give any desired included angle to the spray, and this included angle should be selected to meet particular conditions of heater operations and sizes of heater. I have found, however. that an included angle of 80 operates very successfully in the heater shown in Fig. 1. It is to be understood, however, that changes in any of the dimensions or arrangements of the several parts of the fuel mixing parts of this heater may make some other angle of fuel delivery more desirable.

Combustion air is supplied to the combustion chamber It by way of a combustion air pipe 38. This pipe is illustrated as having a flange 40 welded to its upper end and as being secured to the casing ill by bolts 42 which pass through this casing and flange 40. In the particular embodiment illustrated, these bolts also secure to the casing l 0. the flange 44 of connecting pipe 48 which is supplied with combustion air by a ram, blower, or other suitable means. The combustion air pipe 38 extends through the cylindrical wall iii of the combustion chamber in a direction radial to the axis of this chamber. and is welded to this side wall as indicated at 18. The lower or delivery end of the pipe 38 is curved as indicated at 50, to bring the extreme straight end portion 52 of the pipe in axial alignment with the nozzle 26. The delivery end of the pipe 88 is preferably provided with partitions or vanes 54 which maintain substantially even distribution of the air throughout the cross section of the pipe and prevent a majority of the air from following closely along the outside wall of the curve.

The air discharged by the pipe 38 flows directly toward the rounded head of the nozzle 26 and in a direction generally opposite to that of the fuel spray leaving the nozzle. This counterflow of fuel and air promotes vaporization and 5 thorough intermixing of the fuel with the combustion air to form a substantially homogeneous, highly combustible mixture. It should be noted that that portion of the combustion air pipe 38 which is located in the combustion chamber serves as a preheating means for the combustion air so that when the heater is in operation. the preheating of the combustion air aids in the va porization of thefuel sprayed into this air by the nozzle 26.

The counter-flow of air delivered by the pipe 38 reverses the spray delivered by the nozzle 28, in the manner indicated by the small arrows in Fig.

l, and the mixture of fuel and air formed adjacent the outlet end of the nozzle 26 flows around the sides of this nozzle in a conical pattern and into the annular groove 24.

Particularattention is directed to the fact that the inwardly projecting portion 22 of the end wall of the annular ring 2|, as clearly shown by the arrows in Fig. 1. This leaves a relatively dead space 58 between the whirling vortex of the incoming air and fuel and the adjacent curved portion of the end wall 20. This space is filled with eddy currents of combustible mixture, and these eddy currents may be readily ignited by the hot wire 58 of the usual electrical ign'iter 60, whereas if the wire 58 of this sniter were located directly in the main stream of air and fuel entering the annular groove, the flow of this mixture would tend tocool the wire 58 below igniting temperature. The igniter 60 is preferably provided with the usual thermostatic switch (not shown) for cutting out this igniter after the heater has attained normal operating temperature. Thereafter the burning eddy currents in the dead space it effectively maintain combustion so that the usual reigniter may be dispensed with.

The whirling vortices of burning gases which are first formed in the annular recess or groove 24, move from this groove toward the heat exchanger I I, and as these whirling vortices move lengthwise of the combustion chamber, they move readily inward of this chamber, as indicated by the arrows in Fig. 1. As these vortices converge inward, they strike each other to create further intermixing of the burning gases and thereby produce ideal conditions for rapid and complete consumption of all fuel contained in these cases. This is an important feature of my invention, as it insures most complete and eflicient combustion of the fuel and has the further advantage of shortening the total length of the flame under any given conditions of operation. This means that the combustion chamber may be made of minimum length, and that for any given size of combustion chamber the flame will extend a minimum distance into the heat exchanger Hi. In this connection. it should be understood that in aircraft operation, the flame lengthens as the plane ascends, since the combustion air must be delivered to the combustion chamber at a greater volumetric rate of flow to compensate for its decrease in density.

In heaters of this type, and particularly in aircraft heaters where the flame is greatly elongated at high altitudes, it is ordinarily impracticable.

to make combustion chamber of such length that all combustion takes place therein. In this type of heater, therefore, part of the combustion occurs in the adjacent end of the heat exchanger, and in that type of heater wherein the burning gases are given a spiral flow, these burning gases con tact the heat exchanger mainly over a relatively restricted surface. The tendency is to heat this restricted surface to an unduly high temperature, with the result that this part of the heat exchanger has a shorter life than other parts of the heater.

Another important feature of my invention is to provide a type of combustion chamber which 5 causes the burning gases to issue therefrom in a substantially uniform flame directed longitudinally of theheat exchanger so that the inner wall 20 is so curved that the mixture of fuel and 78 her from the annular oov 24 to about the center Of'the side wall I8. This converging of the whirling vortices, as hereinabove pointed out, creates additional intermixing of the burning gases and promotes most efllcient combustion. The converging vortices tend to break up as they converge and interengage, and to produce a continuous uniform flame extending lengthwise of the combustion chamber, and fanning out from the center thereof toward the heat exchanger. The whirling gases tend to form a cone with its narrower or more pointed end in the heat exchanger, and .the narrower end of this cone is surrounded by axially flowing gases which are burning at a lesser rate than the centrally located vortices, or are completely burned out. This flame structure is indicated by the arrows in Fig. 1, and leaves an annular dead space 62 adjacent the side wall of the combustion chamber. As clearly indicated in Fig. 1, this dead space 62 is of greatest width adjacent the longitudinal center of the combustion chamber, and is filled with eddy currents. The flaming gases entering the central chamber 64 of the heat exchanger I4, fan out as indicated in this figure, and engage the adjacent portion of the wall of this chamber substantially uniformly throughout its circumference.

As hereinabove pointed out, the length of the flame created by the burning gases will vary with altitude, and at high altitudes this flame may extend a very appreciable part of the length of the central chamber 64 of the heat exchanger.

Regardless of the extent to which the fiame penetrates this chamber, however, the wall of this chamber is heated to a substantially uniform temperature throughout a circumference at any given distance from the combustion chamber.

A still further feature of my invention lies in the fact that the stream of combustion air flowing directly toward the fuel nozzle 26 prevents the accumulation of soot on the exterior surface of this nozzle and maintains the nozzle clean at all times. The stream of combustion air also cools this nozzle and prevents it from becoming overheated and warped, or otherwise impaired. This cooling of the nozzle also aids in preventing both the occurrence of vapor-lock in the nozzle due to gasification of the fuel within the nozzle or fuel supply line, and cracking of the fuel with resultant deposit of carbonaceous material in the tangential slots 34. This cooling of the nozzle, therefore, promotes maintenance of proper spray characteristics throughout the life of the heater.

In Fig. 1, the ventilating air is illustrated as entering the tapered end I2 of the heater casing I0. Withthis direction of airflow, the air first passes over the combustion chamber and absorbs some heat therefrom, and then passes into the heat exchanger I4 where it receives additional heat. This particular direction of flow, however, is not important, and my novel heater will operate equally well if the flow of ventilating air is reversed so that it first passes through the heat exchanger and then over the combustion chamber.

In Fig. 2, I have illustrated a modified form of my invention wherein the side wall I of the combustion chamber I02 is given a Venturi-like shape so that this side wall more nearly approaches the flow pattern of the whirling vortices of burning gases. This Venturi-like shape of side wall reduces the thickness and length of the annular dead space I04 formed adjacent the interior of this wall, and by reducing the volume of eddying gases in the combustion chamber, reduces resistance to flow through this combustion chamber, and thereby reduces the overall flow resistance of the heater.

The heater of Fig. 2 may in all other respects be identical with that of Fig. 1. In Fig. 2, however, instead of supplying the combustion air from a separate ram or blower, the combustion air is supplied by the same ram or blower which furnishes the ventilating air for the heater, although either source of combustion'air supply is equally available for use in either of these modifications. In Fig. 2, the combustion air pipe I06 has a bent and slightly flared upper end I00 directed o posite tothe general direction of flow of ventilating air in the adjacent portion of the heater casing I I0, so that part of this ventilating air enters the combustion pipe I06. The lower end of this pipe I06 ma be identical with the lower end of the combustion air pipe 38 of the previous embodiment. In Fig. 2, both of the curved portions of the combustion air pipe I06 are provided with vanes or transverse partitions I I2 to provide more uniform flow of air throughout the entire cross section of the pipe I06.

In Figs. 3, 4, and 5. I have illustrated my invention as being applied to a heater, which is supplied with combustible mixture bv a carburetor I50 of any conventional or suitable type. This carburetor receives fuel through a fuel supply pipe I52 controlled by the usual solenoid valve I54. The carburetor receives combustion air through a combustion air pipe I56 which passes through the tapered outlet end I58 of the heater casing I60, and this end of the combustion air pipe is so positioned that part of the heated air leaving the heat exchanger I4 flows into this pipe end to the carburetor I50. The remainder of the heated air leaving the heat exchanger I4 passes into a duct I62 leading to the aircraft cabin or other space orspaces requiring heat.

The combustible mixture of fuel and air formed by the carburetor I50 passes into an induction pipe I64 which extends through a wall of the heater casing I60. and a wall I66 of the combustion chamber I68. The delivery end of the induction pipe I64 may be identical with the delivery ends of the, combustion air pipes of the previous embodiments. As shown in Fig. 3, the delivery end of the induction pipe I64 is curved as indicated at 'I10, and has a straight outlet portion I12 coaxial with the cylindrical wall of the combustion chamber, and directed toward the dome-shaped inward projection I14 provided by the end wall I16 of the combustion chamber.

This end wall has essentially the same shape as the end walls of the two previous embodiments so that the mixture flows into the annular recess I18 and forms whirling vortices of burning gases as in the previous embodiments. The dome-shaped projection I14 is so curved that the combustible mixture flowing into the annular recess I18 does not closely follow the walls of this recess, but provides a dead space as in the previous embodiments. The combustible mixture in this dead space is initially ignited by the igniter 60 as is the embodiments of Figs. 1 and 2.

The heat exchanger I4 is generally of the type disclosed and claimed in my Patent No. 2,432,929, issued December 16, 1947, and has a heat transfer means formed of a piece of sheet metal I bent back upon itself, as indicated at I02, to form a double walled structure which is spiraled assays? as indicated at I86.

From Fig. 4 it will be apparent that the double walled structure is provided with longitudinally extending spacing ribs I88 which determine the thickness of the double wall structure. I have found it most desirable to decrease the thickness of this double wall structure as it approaches the casing I and I have accordingly made the end ribs I 88' and I88" of progressively decreasing height, as clearly shown in Fig. 4.

The righthand ends of the central chamber 64 and of the spiral gas passage I84 communicating therewith are closed by a plate I90 having a spiral-like extension Ii90' and secured to the edge of the sheet metal plate I80 by welding or in any other suitable manner. The plate I90 has attached thereto a supporting bracket I92, having a pin I94 carried in asecond bracket I96 bolted or otherwise suitably secured to the casing I 0.

Another plate I98 having a spiral extension I98 serves to attach the cylindrical wall I 66 of the combustion chamber to the lefthand end of the heat exchanger. and to close the lefthand end of the spiral gas passage in this heat exchanger. A bracket 200 supports the combustion chamber and adjacent end of the heat exchanger in the casing I0.

A plurality of resilient clips or plates 202 (Fig. 4) each have an end 204 welded or otherwise suitably secured to the interior of the casing Ill. The other ends of these clips or plates are free to slide against the inner wall of the casing I0. These clips or plates-serve to center the heat exchanger I4 in the casing I0 while per mitting adjustment of the heat exchanger relative to the casing resulting from expansion and contraction of the heat exchanger due to starting and stopping of the heater. In effect, there is a floating mounting for the heat .exchanger which provides for clockwise and counter-clockwise rotation of the outer portion of the heat exchanger relative to the casing and which also permits the heat exchanger to shift sidewise of the casing to prevent any portion of the outer part of the heat exchanger from approaching too closely to the casing. The pin I94 is also arranged so that it may slide axially in its supporting bracket I96 to provide for axial expansion and contraction of the heat exchanger.

The products of combustion are discharged through an exhaust nipple 208 which is welded or otherwise suitably attached to the outwardly flared walls 208 of an opening punched in the sheet metal I80. This nipple extends through a relatively large opening 2I0 formed in an adjacent portion of the wall of the casing I0 whereby the nipple 206 may shift both circumferentialiy and axially of the casing with expansion and contraction of the heat exchanger. This portion of the casing wall is pressed outwardly to provide a flat shoulder 2I2 against which an annular sealing member2l4 is pressed by a spring 2I6. The sealing member 2I4 is slidably mounted on the nipple 206 and serves to form a sealed connection between this nipple and the shoulder 2l2. An annular spring abutment M8 is 8 weldedcrotherwisesnitablysccm'edtothenipple 286. Any suitable exhaust Pipe 228 (Fig. 3) may beconnectedtothe nipple288 andfromthis figure it will be observed that the nipple 288 is located adjacent the rlghthand end of the heat exchanger sofliat the products of combustion travel a maximum distance before passing out of the exhaust nipple.

The inlet I2 is supplied with air by aram, blower or other suitable means and this air first passes aroimd the combustion chamber from which it absorbs some heat. Some of this air then passesthrough the longitudinal air passages 222 formed between the longitudinal ribs of the heat exchanger. The remainder of the airpassesbetweentheoutermostportionofthe heatexchangerandthecasing I0. Astheair travels either of these paths, it receives additional heat from the heat exchanger and is dischargedinto the outlet I 68. Some of the heated airentersthecombustionairpipe I86 leadingto the carburetor 150, whereas the remainder lively small and since throughduct I82 tothe spaceor spaces tobeheated. WhiieIliaveshowntheairas traveling from left to right thro h the ces z I0, the heater is equally adapted for opposite direction of air flow by simply transferring the inlet end of the combustion air pipe from one end of the heater to the other.

Where the fuel is supplied to the combustion chamber in the form of a combustible mixture delivered from a carburetor of any usual or suitable design, any usual or suitable means may be provided for regulating the heat output of the heatenby varying the rate of fuel supply to the cmnbustion chamber. However, where the fuel is delivered to the combustion chamber by means ofaspraynomlelikethespraynozzlefiofl'lgs. 1 and 2, thefuel mustbe delivered to the nomle atsomeminimumpressureorthemelwillmerely dripfromthe nosrleinsteadofissuingtherefrom intheformofaspra Afuelspray'isn forpropervaporisationandmixingofthefuel andair,sndwhilethepressurento cansethefueltoissuefromanomleintheform ofaspraywillvarywithdiflerentnomesinaccordance with their dimensions and details of design, it is imdesirable, particularly in aircraft pressure. Therefore, the pressure range available for v rying the rate of fuel delivery is relathe rate of fuel delivery varies as the square root of the pressure, this constitutes a serious limitation to the operation ofaheater overawideheatoutputrange. In

' Fig. 6, I have illustrated a modified form of my invention which is particularly adapted to overcome this difliculty.

Inthisflgure.Ihaveillustratedaheater which may be identical with that shown in Fig. 1, exv p forthedetaiishereinafterpointedout. In thisl'lg. 6, a part only of the fuel is delivered to the' chamber I8 by the nozzle 28 when the heater is operating at maximum heat 26' is provided and discharges into the combustion air pipe 88', which is identical with the pipe 88, except for the provision of a threaded nipple 280 into which the nozzle 28' is screwed.

Whilethenozzles 26 and 20' maybemade of anyrelativesiaessothatthetotalfuel consumption of the heater is split between these nozzles in any desired ratio, 1 have found it preferable to utilise identical nozzles so that each delivers fueltothenozzleathigh one-half of the total fuel supplied to the heater at maximum operation.

Both of the nozzles 26 and 26' are connected to fuel supply pipe 252 which may be provided with any usual shut off valve. A solenoid or other remote control valve 254 is interposed between nozzle 25' and pipe 252 so that the fuel delivery to the nozzle 25' may be cut off independently of the fuel delivery to the nozzle 25. The fuel spray delivered by the nozzle 26' is transverse to the direction of flow of the combustion air in pipe 38' and does not initially form a homogeneous mixture with this air. This mixture, however, is improved as it absorbs heat from the lower end of the pipe 38' and any remaining lack of homogeneity in this mixture is overcome when this mixture is admixed with the spray from the nozzle 26 to form a final combustible mixture. This final mixture is ignited by the igniter 50 and burns in the manner described in the discussion of Fig. 1.

When the heater is operating at maximum output, both nozzles 26 and 26' are supplying fuel. If it is desired to operate the heater at one-half maximum heat output, it is only necessary to close the solenoid valve 254, thereby cutting off all fuel supply to the nozzle 26. Under this condition of operation, the nozzle 25 supplies all of the fuel burned in the heater and the operation is identical with that of Fig. 1.

In most instances it will be sufficient to provide a heater having only two stages of operation and for such use the heater of Fig. 6 is ideally suited.

For these conditions the fuel can always be supplied to the nozzles at minimum efiective operating pressure and all heat output control is effected by opening and closing the solenoid valve 254. This is particularly desirable where conditions of use dictate a. low pressure fuel supply for the heater. Where the heater is to be used under operating conditions which call for greater flexibility in heat output, the necessary additional flexibility can be secured by varying the pressure at which the fuel is supplied to the nozzles 26 and 26' in the same manner in which different heat outputs are obtained in the embodiments of Figs. 1 and 2.

In describing the previous embodiments of my invention, I have referred to the fact that the air may flow through the heater casing in either direction. In this Fig. 6, I have shown the air as flowing from right to left, although in the tion and equivalents coming within the scope of the appended claims.

I claim:

1. A burner of the class described comprising means forming a combustion chamber having an annular wall and an end wall, said end walllhaving an inwardly extending projection on the axis of said annular wall and having an annular recess surrounding said projection, said projection, said end wall and said annular wall merging smoothly to form a surface of revolution which consists of substantially half a tore, a spray nozzle disposed at the end of said projection and oriented to direct a spray of liquid fuel axially of said combustion chamber and in a direction away from said end wall, combustion air delivery means disposed within said combustion chamber comprising a pipe extending substantially radially into a position in front of said combustion chamber, the inner end of said pipe being curved so that the opening at the inner end thereof faces said projection, and vanes within the curved portion of said pipe for subdividing and transversely distributing the flow of air therethrough so that the spray from said nozzle and the stream of combustion air are in counterflow relation to each other, means to supply liquid fuel under pressure to said nozzle, and means to supply air under pressure to said combustion air delivery means.

2. A burner of the class described comprising means forming a combustion chamber having an annular wall and an end wall, said end wall having an inwardly extending projection on the axis of said annular wall and having an annular recess surrounding said projection, said projection, said end wall and said annular wall merging smoothly to form a surface of revolution which consists of substantially half a tore, and means in said combustion chamber for directing a stream of mixed fuel and air at said inwardly extending projection and in substantially axial alignment therewith comprising a pipe extending substantially radially into a position in front of said combustion chamber, the inner end of said pipe being curved so that the opening in the inner end thereof faces said projection, and vanes within the curved portion of said pipe for subdividing and transversely distributing the moving stream therein so that said stream is divided by said projection and flows radially outwardly in all directions to form a vortex within said combustion chamber.

3. A burner of the class described comprising means forming a combustion chamber having an annular wall and an end wall, said end wall having an inwardly extending projection on the Thi is particularly important where atmospheric axis of said annular wall and having an annular recess surrounding said projection, said projection, said end wall and said annular wall merging smoothly to form a "surface of revolution which consists of substantially half a tore, and means in said combustion chamber for directing astream of mixed fuel and air at said inwardly extending projection and in substantially axial alignment therewith comprising a pipe extending substantially radially into a position-in front of said combustion chamber, the inner end of said pipe being curved so that the opening in the inner end thereof faces said projection, vanes within the curved portion of said pipe for subdividing and transversely distributing the moving stream therein so that said stream is divided by said projection and flows radially outwardly in all directions to form a vortex within said combustion chamber. and means for introducing 11 fiuld fuel into said P p at a point upstream or said curved portion.

5 The following references are of record in the WILLIAM C. PARRISH.

imr'mmcns 0mm Number Name Date Shaw June 2, 1863 Hall Nov. 12, 1907 Llnga sent. 8, 1914 Rector Jan. 28, 1919 Thompson Nov. 2, 1920 15 Walker Nov. 20, 1928 Number I Number Iomdes Nov. .10. 1925 Beach at u. Oct. 2a, 1928 mm Feb. 11; 1930 Gomtrr Date Greet mm Feb. 1a, 1933