US2175866A

US2175866A - Fuel burner

Info

Publication number: US2175866A
Application number: US720826A
Authority: US
Inventors: Philip S Arnold
Original assignee: Individual
Current assignee: Individual
Priority date: 1934-04-16
Filing date: 1934-04-16
Publication date: 1939-10-10
Anticipated expiration: 1956-10-10

Description

Oct. 10, 1939. P. s. ARNOLD FUEL BURNER 3 Sheets-Sheet 1 Filed April 16, 1934 INVENTOR.

PHILIP 5 ARNUL-D Oct. 10, 1939. P. s. ARNOLD FUEL BURNER Filed April 16, 1934 3 Sheets-Sheet 2 INVENTOR. PHILIP 5.ARNDL:D.

ATTORNEY.

Oct. 10, 1939. P. s. ARNOLD FUEL BURNER 3 Sheets-Sheet 3 Filed April 16, 1934 can 00 INVENTOR.

Pl-nmp S.ARN:1L.D.

ATTORNEY.

Patented Oct. 10, 1939 UNITED STATES PATENT OFFICE 7 Claims.

This invention relates to fuel burners, and the principal object of the invention is to provide a burner operating upon a new principle of combustion, the burner construction and manner of introduction of the fuel and air for combustion being productive of a highly eflicient method of combustion of low grade liquid, or a solid or gaseous fuel. Preferably, my improved fuel burner comprises a chamber into the bottom of which fuel is injected in any of its convenient forms such as a liquid hydro-carbon or powdered combustible material and enough air is injected into the fuel body to produce suilicient combustion to raise the temperature of the remaining portion to above combustion temperature and then passes into a zone wherein air is added at successive points of its travel suflicient in volume to produce complete combustion.

A further object of the invention is to provide a combustion chamber in which the combustion is attained withoutreverberation. In the present forms of combustion chambers or devices a reverberatory combustion is produced due to the turbulence resulting from the non-uniform rate of heat absorption through various parts of the fuel and air body. This invention seeks to avoid turbulence of combustion and therefore secure a quiet high capacity combustion chamber for continuously burning any fuel capable of a practical continuity in supply.

An additional object of the invention is to provide a new and unique burner structure positioned exteriorly of the furnace and including a refractory lined combustion chamber so constructed as to reduce the noise of combustion therein to a minimum.

A further and primary object of the invention is to provide a combustion chamber of such construction that combustible gases introduced thereintopass spirally to a discharge opening,

the wall of the chamber having apertures for the admission of air at successive spaced points to introduce air progressively into the gases as they pass through the chamber.

A further object of the invention is to provide in a combustion chamber of the character described a construction tending to restrict the rapidity of movement of the gases linearly through the chamber.

It is also an object of this invention to provide a combustion chamber having a nozzle connected with a fuel pipe or conduit for injection of air, steam or gas and fuel into the chamber under pressure to cause atomization or separation of the fuel and to impart velocity thereto. a

valve for varying the flow of fuel in the fuel pipe per unit of time, and means for positioning the valve relative to its seat actuated by pressure of air in the air pipe and a temperature controlled means for varying the pressure in the air pipe to thereby variably position the fuel valve relative to its seat and thus vary the flow of fuel and air per unit of time in the fuel pipe in accordance with temperature change in the area being heated.

Further features of the invention are involved in the construction of the parts for providing the air and fuel and the associated control devices whereby a high efliciency is attained in opera tion coupled with a minimum expense of construction, all of which are hereinafter more fully described and claimed.

A preferred form of construction of an oil burner embodying my invention including the arrangement of the burner in relation to a furnace of the ordinary coal or wood burning type is shown in the accompanying drawings in which- Fig. 1 is an elevation showing my improved burner as applied to a domestic heating furnace. v Fig. 2 is an enlarged vertical section of the burner proper and the associated control devices.

Fig. 3 is a section of the combustion chamber taken on line 3-3 of Fig. 2.

Fig. 4 is a section taken on line 4-4 of Fig. 2 showing the safety control.

Fig. 5 is a section similar to that shown in Fig. 3 showing an alternative form of construction of the combustion chamber at the point of introduction of the fuel.

Fig. 6 is a similar view of another form of construction of the combustion chamber.

Fig. '7 is a longitudinal section of a convenient form of atomizing nozzle.

Fig. 8 is an elevation partly in section showing an alternative form of construction of a combustion chamber and its relationship to a domestic heating furnace.

Figs. 9 and 10 are sectional views of alternative forms of the combustion chamber,

Fig. 11 is a vertical section of another form of combustion chamber.

Fig. 12 is a section taken on line 2l2 of Fig. 11.

Fig. 13 is a vertical section of a further modifled form of combustion chamber.

In Figs. 1 and 2 is shown a preferred form of the construction and arrangement of the burner and the means for supplying air and oil under pressure thereto, the burner being housed in the casing indicated at I and to this casing is connected a conduit 2 opening to the exhaust flue 3 of the furnace indicated generally at 4. A valve 5 is provided in the flue 3 which, when in the open position as shown in Fig. 2, directs the gases of combustion into the flue and into the radiator ring 6 or chamber of the furnace through which the gases of combustion usually pass when used in the ordinary way in the burning of fuel and in my arrangement, these gases pass downward through the radiator, firepot, grate, ashpit, and thence out through an auxiliary flue I which is here shown as discharging into the exhaust flue 3 adjacent the stack (not shown) in the wall I. The heating of these usual channels for heated gases in a hot air furnace heats the air in the exterior shell of the furnace and this heated air passes through the usual fiues 9, 9 to the rooms of a building to be heated. The casing I having my improved burner may be formed of any approved material, preferably metal, and the exterior thereof may have an insulating covering I particularly about that portion thereof immediately surrounding the combustion chamber I I to prevent material loss of heat to atmosphere.

The combustion chamber II is preferably formed of a refractory material and the bottom section thereof, indicated at I2, is greater in diameter than the body I3. The bottom wall of the chamber is provided with a series of apertures I4 for inflow of air and the side walls of the bottom portion I 2 are provided with the tangential apertures I5. The body of the chamber above the bottom wall has apertures I6, preferably tangential, opening therethrough. There are also a series of air inlet holes II at the open upper end ll of the combustion chamber II. This end I8 closes the interior of the casing I to the conduit 2 so that air in the casing must pass into the combustion chamber to complete combustion. The flue 2, valve 5. and the walls of the tube 3 to the point of entrance into the combustion chamber and channel 6 of the furnace are lined with a fire resistant material indicated at I9. To the bottom wall of the combustion chamber II and adjacent the nozzle 22 is connected a fuel pipe having a valve 2| for control thereof to provide a pilot light. Liquid or other form of fuel in atomized condition is discharged through the nozzle 22 into the bottom section I 2 of the combustion chamber as shown in Fig. 3 from which it will be observed that the atomizing nozzle by discharging the fuel stream tangentially into the chambercauses the supplied fuel to pass circumferentially thereabout in order that burned and/or unburned gases will partially or wholly envelop the fuel Jet. This condition is enhanced by extending the wall of the chamber at the nozzle aperture inwardly of the circumference to provide a shield for the nozzle as indicated in Fig. 3 and preventing contact of free air with the let.

The atomizing nozzle is shown generally in Fig. 7 and is a common form of structure having an exterior shell 24 through which air under high pressure is fed from the pipe 25 and within this member 24 is the terminal portion 26 of the oil supply pipe 21. The discharge end 23 of the pipe 2! is of a smaller diameter and terminates at the opening 29 of the shell 24 through which air flows parallel to the end of this tube and past the button 30 to produce spray. This is a common form of atomizing nozzle and other forms of nozzles adapted for the purpose may be utilized if desired without departing from the spirit of this invention.

In the form of construction of the bottom section of the combustion chamber shown in Fig. 5. a single nozzle 22 may be employed discharging centrally between two circular portions providing chambers 3| and 3|. In the construction shown in Fig. 5, the wall of the chamber opposite the nozzle has the inwardly extending point or portion 33 with curved side walls and at the nozzle has similar curved portions of the wall thereabout. The inwardly projecting portion 33 divides the fuel and air stream causing the same to circulate in opposite directions around the chambers 3i and 3i and the curved portions at the nozzle deflect the air and fuel stream from direct contact with the nozzle end and thus shield the nozzle from the rotating gases. In either of these chambers shown and in any form of the combustion chamber the apertures I5 for inflow of air into the fuel stream should extend practically tangentially through the wall or at least at a material angle to a radial line of the circular chamber and in a direction to permit air to pass into the chamber in approximately the direction of flow of fuel discharged by the nozzle.

Thus the inflow of air tends to accentuate the rotation of the gaseous body in combustion and preferably in any of the constructions of the combustion chamber shown, the wall, as the wall 34 shown in Fig. 2, between the body and the bottom sectionor chamber I 2, is inclined or so constructed as to tend to delay movement of the gases in combustion axially through the body of the burner. Ignition of the fuel takes place in this bottom section and theinflowing fuel body is raised in temperature to above the combustion temperature. To continue the combustion, the openings I6 are provided in the body in order to discharge air into the gases in passing upwardly toward the exhaust fiue 3 of the furnace. Air passing through these apertures I4, I5, I6 and II in the form of combustion chamber shown in Fig. 2 is provided by a fan 35 which is positioned above a dividing wall 36 in the casing I and takes its supply through an aperture 31 opening to the lower chamber 33 of the member I. The chamber 38 is open at its bottom to atmosphere through a conduit 39 having a valve 40 for varying the area of the opening, the control of which is hereinafter described. The fan 35 is driven by a motor 4I supported on a base 42 suspended from the dividing wall 36 by the studs 43.

For supplying air under pressure to the nozzle, I provide a two-cylinder compressor supported from the base 42 on which the motor is mounted and this apparatus consists of a casing providing a chamber 44 containing oil for lubrication purposes and the compressor consists of the two outwardly disposed cylinders 45 and 46 and companion pistons operated alternately by any approved means as an eccentric 41 on the motor shaft.

The said shaft has a bearing in a central column 48 in the chamber 44 and the column has an aperture 49 opening into the chamber below the 011 surface and leading upwards to the bearing for the motor shaft. The pistons have the usual spring valve 50 in the outer end which opens on the instroke of the piston and closes on the outgoing stroke and the head of the cylinders is formed with an aperture 5| covered by a recessed plate 52. An aperture 53 is provided from the recess of this plate to the interior of the chamber 44. Thus the air is taken from the interior 3. of the casing i in which the compressor is mounted through the motor ll and through apertures ll in the base 42 and is discharged into the chamber 44 and thus the oil in the said chamber is under pressure and is caused to lubricate the bearing for the motor and compressor. This oil under pressure may, by a conduit, (not shown) lead to any part of the apparatus which requires to be oiled.

The chamber 44 acts as a storage tank for air under pressure and the air line 25 has its intake end in this chamber above the oil surface and upturned as shown to prevent any material amount of oil entering the same. As before described, the air line 25 opens to the nozzle as shown in Fig. 7. The oil line 21 has a constant level chamber 54 and leads to the atomizer or nozzle as indicated in Fig. 7. The compressor may be of any type providing for substantially constant air pressure.

The control of the burner in operation is accomplished by the following described mechanism:

Connected into the fuel pipe 21 is a control valve 55 and this valve has a stem 56 connected to a lever 51 hinged at one end to a diaphragm casing 55 and the opposite end of the lever 51 is connected by means of a lever 55 with the valve 4|] controlling the air inlet to the casing through which the fan is supplied. The lever 51 has a spring 60 tending to close the fuel valve 55 and also to restrict the air opening through the turning of the air valve 40. The lever also has a bearing 5l opposite the pivotal connection with the oil valve stem 56 engaging the flexible diaphragm 6i forming one wall of the casing 56. The chamber of the casing 58 is connected to the air line 25 by a pipe 58 through which air under pressure is supplied to automatically open the valve and permit flow of 011. Thus it will be observed that the oil valve 55 and the valve or .shutter may both be operated or adjusted in unison and the proper proportion of the air and oil are admitted to the combustion chamber II for accomplishing complete combustion. The construction shown in Fig. 2 is an arrangement adapted for use with oil or gas as a fuel. With a powdered fuel some change in construction of the valve would be required but the relationship of the parts would be substantially the same.

The compressor preferably has a constant output greater than is required by the atomizing nozzle or nozzles and to control the operation of the burner, I provide a thermostat, indicated generally at 62, which may be located at any convenient point of the building or space to be heated. The thermostat consists of a bimetal helix 63 for operating a needle valve 64 normally closing the opening to a conduit 65 connected with the air line 25 here shown as being connected to the line 25 through the conduit 58' for the diaphragm chamber. Due to an excess temperature in the heated space the thermostat opens the conduit 65 permitting escape of air, thereby reducing the pressure in the diaphragm chamber 58 permitting the lever to act under tension of the spring 60 to partially close the valve 55. Under the opposite condition, that is, a reduction in temperature of the heated space, the helix operates to close the needle valve 64 which tends to build up the pressure in the diaphragm chamber thereby opening the fuel valve 55 to a greater extent and also opening the valve or shutter at 40 to increase the air flow to the fan 35 and thus increasing the heat output of the burner.

There is an additional safety control shown generally at 66. This, as shown in Figs. 2 and 4, consists of a bimetal helix 55' mounted rigidly at one end on the end of a tube 61 which is screwed into an aperture provided in the radiator ring or channel 6 of the furnace and attached to the inner end of the helix and'extending out through the tube 61 is a shaft 56 on the outer end of which is mounted a disc 65 having a notch II in its periphery.

When the temperature of the helix is not increased by combustion gases passing through the radiator ring from the combustion chamber H the disc rests in such a position that a pin II mounted on the end of a pivoted lever 12 is held in the notch by tension of the spring 11. The lower end of the lever 12 is connected by a link 13 with a needle valve ll having a stem riding in a guide 15. The valve may seat in the end of the tube 16 connected with the air supply pipe 1 56' and thence with the main air supply pipe 25. The toggle structure consisting of the lever I2 and link 15, is so arranged that when the pin ll rests in the notch in the disc 65, the needle valve 14 is open.

If at any time the fire in the combustion chamber goes out, the helix in the radiator ring is allowed to cool and thus rotate the disc 65 to bring the notch 10 opposite the pin permitting the lever to be moved by a spring 11 to open the valve 14 releasing the air pressure and closing the fuel valve. Flow of raw oil into the combustion chamber is thus prevented.

To start the burner, the lever 12 may be manually held in the position shown in Fig. 2 with the valve I4 closed. This causes a rise of pressure within the air supply pipe through operation of the motor and compressor which is understood to be in operation at the time and the consequent deflection of the diaphragm 6| to the position shown in Fig. 2 opens the fuel valve. After the fire has been burning a short time the helix in the furnace radiator ring 6, which has become heated, rotates the disc so that the lever upon release by the operator has the pin H resting upon the periphery of the disc thereby holding the. needle valve 14 closed and the fuel valve 55 open permitting the burner to continue in operation.

It is to be seen from the foregoing that there are preferably two instrumentalities for controlling the oil burner, one consisting of the thermostat structure 62 for varying the rate of consumption of oil to correspond with the temperature changes in the room being heated, and the other consisting of the safety control 66 both of which operate through a release of air pressure in the air supply pipe connected to the nozzle or nozzles. The room thermostat structure 62 and capacity of the port controlled by the needle valve 64 is such as to reduce the pressure but not to such extent as to quickly or fully close the fuel valve and its operation is therefore to control the burner in the amount of fuel consumption while the structure indicated generally at 66 is adapted to cause complete cessation of the fuel flow.

It will be observed that in the event of breakdown of the oil burner structure and necessity for continued use of the furnace through consumption of fuel within the furnace itself, the valve 5 in the exhaust flue 3 is closed and a valve TI in the flue I is closed. This permits the furnace to be operated in the usual way with the fire in the grate indicated by the dotted line II and the products of combustion will pass out through the usual exhaust conduit I. Under this condition, the valve plate 5 prevents soot or dust from entering the oil burner chamber. When used with the oil burner the valve 5 is open and the valve TI is also open so that the products of combustion pass through the radiator ring 6 downward through the furnace and out through. the flue I.

The combustion chamber itself constitutes one of the primary features of this invention, namely, a chamber of fire resistant material into which oil is discharged tangentially and to which air is progressively provided through apertures therein as the combustible products pass linearly through the chamber to finally discharge into the furnace. The invention is not confined to the use of a combustion chamber as shown in Figs. 1 and 2. An equivalent arrangement is indicated in Fig. 8 where the burner proper con sists of the shell Il of refractory material placed in the ash pit.

The oil nozzle 19 leads tangentially with the shell 18' in the same manner as the nozzle 22 of the burner shown in Fig. l. The open upper end of the shell ll discharges up through the normal combustion chamber and the usual radiator ring 6 of the furnace to the exhaust, flue 3'. Air may be provided by means of. a fan and motor therefor indicated at l! and while I have not shown the motors etc., for provision of oil and air in atomization of the fuel, apparatus such as is described in conjunction with the structure shown in Figs. 1 and 2 may be employed. Although not shown, this burner structure 18 is provided with a pilot light as shown with burners previously described. The combustion chamber may also be made as shown in Fig. 9 and may be made of a metal wall ll on the exterior of the refractory wall 82 and a nozzle is shown at I! entering the lower portion of the combustion chamber which is provided with a ledge 84 to prevent too quick a rise of the combustible gases into the main body of the burner.

Another convenient'form is shown in Fig. 10, which is preferably conical, having the tapered walls 85 of the same character and construction as shown in Fig. 9 and the lower end of greater diameter than the open discharge end It. This tapered inwardly inclined wall tends to delay passage of the gases until combustion has been practically completed within the chamber and in either of the combustion chambers shown the nozzles lead thereinto to cause rotational movement of the gasified elements and the smothering of the fuel jet.

In Figs. 11 and 12 is shown a different form of chamber, the principal feature of which is a construction providing for entry of air for combustion centrally of the rotating bodies of the gases in combustion. This arrangement is a useful form and is particularly useful where the burner shell III is of large diameter. The casing has a re-entrant portion llll open at the bottom for flow of air thereinto and has its walls provided with tangential apertures ill! for causing air to flow into the fuel body in the same direction as the outer tangential apertures ID! in the main shell. In all forms of combustion chambers carbon accumulation is prevented by the layer of air introduced between the flame and chamber wall.

The re-entrantportion extends centrally into the chamber and has openings I in the top thereof to provide additional air to the center of the gases of combustion as they pass into the outlet I 05. With a rotating body of the gases and air entering only from the exterior of the gaseous body, the central portion does not in some cases receive sufficient air for combustion or at least for complete combustion by the time the gases pass from the chamber and this, of course, varies with the diameter of the body of the rotating gases. By the arrangement shown, the gaseous body is provided with air in the interior as well as the exterior thereof. In Fig. 13 is shown another convenient form of chamber in which the fuel is discharged in the bottomi chamber I06 and ignited as in the other cases described. The walls of the combustion chamber above the chamber I08 are outwardly inclined so that the diameter of the chamber increases toward the outlet llil. By this arrangement there is a greatly increasing quantity of air discharged into the gases as they rise to the outlet. The diameter of the outlet being less than the diameter of the chamber, the volume of flow of the burning gases per unit of time from the chamber is restricted.

By the construction of the combustion chamber hereinbefore described and particularly by the constructions shown more fully in Figs. 1 and 2, a complete burner outfit may be installed in con- Junction with an ordinary wood or coal burning heating furnace without removal of any of the usual furnace parts leaving it all in normal state. The installation may be made at very little cost, it being only necessary to provide the flue I open to the ash pit of the furnace and to the exhaust flue 3 of the furnace to which the discharge flue 2 of the combustion chamber is connected and also to provide a threaded opening in the radiator ring or correspondingly similar structure of the furnace for introduction of the safety trip 66. The burner may thus be completely set up in all its relationship of parts even including the trip 68 at the factory and practically adjusted prior to installation and thus upon installation and connection of the thermostat G2 and air supply pipe therefor and the oil supply pipe the installation is completed and ready for operation.

The combustion chamber forming the principal feature of this invention is not restricted to use with any specific type of furnace construction and may be used in any way that may be found desirable where a complete combustion of gases is desired. The burner may be used in the production of heat for any purpose and, as before stated, the invention is not only in the construction of the combustion chamber and the associated fuel supply pipes etc., but exists fundamentally in the method by which the fuel is progressively burned in passing through the chamber. In so far as this feature is concerned, the fuel may be of various forms in which it is first brought to a temperature above combustion temperature and given a rotary motion and passes linearly or outwardly through the chamber during which air for combustion is added as the gases pass progressively through the chamber. The air may be introduced to the exterior of the rotating body only or to both the exterior and.interior thereof and in the same direction as the body of gases is rotating to increase the rapidity of rotation. By this method of burning a very quiet combustion is attained. This quietness is due firstly to the excess of fuel over air and next to the fact that the fuel jet is surrounded by combustion gases and gasified fuel which presents contact of the free air with the jet and thirdly to the fact that the air is admitted in small streams to the gasifled and heated fuel that are distributed over a comparatively large area and therefore I do not secure a successive ignition within the mixture or a periodic portional heating of the mixture and thus avoid flame noises which are produced in other types of burners through the individual combustion of portions of the combustible mixture which reach ignition temperature at different time periods.

Thus while I have herein described a specific use of my improved combustion chamber, the invention is not confined to such use as the combustion chamber need not of necessity be positioned with its longitudinal axis in vertical position as is the desired arrangement in the use of the burner illustrated. The invention therefore broadly is involved in the combustion chamber and the manner in which combustion takes place.

From the foregoing description it is believed evident that the various objects of the invention are attained by the structures described, and that a comparative simple and economic construction is secured.

Having thus described my invention, its utility and mode of operation, what I claim and desire to secure by Letters Patent of the United States 1. In an oil burner, a combustion chamber havingvertical side walls of refractory material, a bottom, and an open top, the vertical walls of the chamber being provided with tangential openings, a nozzle dischargingv tangentially into the chamber adjacent the bottom, means for supplying a combustible mixture of hydro-carbon fuel and air under pressure to the nozzle, a pilot burner at the bottom of the chamber for igniting the combustible mixture as it passes into the chamber, and means for discharging air in desired volume through the said tangential openings into the combustible mixture in the combustion chamber, said tangential openings providing for addition of air to the combustible mixture at successive points in its path of movement through the combustion chamber whereby combustion is completed prior to passage of the fuel in combustion through the open top of the chamber.

2. In an oil burner, a hollow member provid ing a combustion chamber having a bottom and an opening thereabove for movement of gases of combustion vertically therethrough, the chamber being of greatest diameter at the bottom, the body of the chamber above the bottom being of less diameter and the opening being less in diameter than the-diameter of the body providing a restriction to flow of gases through the chamber, the wall of the chamber above the bottom being provided with tangential openings arranged thereabout in successive horizontal planes from near the bottom to near the top, means for discharging air through the said tangential openings into the chamber, a nozzle discharging tangentially into the combustion chamber adjacent its bottom, means for supplying a combustible oil and air mixture to the nozzle, and means for igniting the combustible mixture as it enters the chamber, the tangential flow of said mixture and of air discharging into the combustion chamber causing the gases in combustion to flow in a rotating stream through the combustion chamber.

3. In an oil burner, a vertically positioned chambered member formed of a refractory material having a bottom wall provided with openings, side walls, and an open top, a nozzle discharging tangentially into the chamber adjacent the bottom wall, means for supplying air and liquid hydro-carbon fuel through the nozzle whereby a whirling mass of fuel and air is provided in the chamber, a pilot light approximately at the center of the bottom wall, the body of the chamber at a comparatively short distance above the bottom wall being of less diameter than at the point of introduction of the fuel and air providing a means for delaying the movement of combustible gases through the chamber, the side walls of the said chamber adjacent the bottom being provided with a series of openings through which air may pass into the fuel and air stream in the direction of its travel and further being provided with a plurality of series of openings in vertically spaced relation in the body thereof above the said bottom portion for passage of air into the chamber whereby air is added to the gases as they pass upwardly to the open top.

4. In an oil burner, a combustion chamber having a bottom wall and a discharge opening thereabove, said chamber having cylindrical bottom and upper sections, the upper section being of less diameter than the bottom section and greater in diameter than the discharge opening providing a structure tending to cause a slow movement of the gases in passing therethrough, means for discharging a fuel and air mixture tangentially into the bottom section, means in the bottom section for igniting the fuel mixture, the wall of both the bottom and upper sections being provided with openings for discharging air tangentially into the fuel and air mixture and maintaining the same in a rotating state in its passage toward the discharge opening, the tangential openings in the wall of the upper section being so spaced that air is discharged into the fuel and air mixture ';at successive points in its path of movement through the combustion chamber and combustion completed prior to flow of the gases through the discharge opening.

5. In an oil burner, a vertically positioned chambered member of refractory material having a bottom and an opening at the top, the wall of the chambered member being provided with a plurality of series of apertures in vertically spaced relation opening to the interior of the said chambered member between the bottom and top, a hollow casing within which the chambered member is positioned, a discharge conduit at the top of the said casing, the interior of the easing being sealed from the said discharge conduit and the open end of the chambered member discharging thereinto, a nozzle for discharge of liquid fuel in atomized form tangentially into the chambered member adjacent the bottom, means for supplying fuel to the said nozzle, and a controllable means permitting air to flow to the interior of the casing to pass through the apertures of the chambered member.

6. In an oil burner, a casing, a conduit at the upper end of the casing, a chambered member of refractory material within the casing and spaced therefrom, said chambered member having a bottom, vertical side walls and an opening at the top discharging to the said conduit, said chambered member being provided with a plurality of series of vertically spaced openings in its vertical walls through which air from the interior of the casing may pass into the chambered member, a fuel pipe for discharging fuel into the chambered member adjacent its bottom, a fan for forcing air into the casing for discharge into the chambered member through the openings in its vertical walls, and means for varying the volume 01 air and fuel flowing into the chambered member per unit or time. 7

'1. In an oil burner, a member providing for a combustion chamber havinga bottom, vertical side walls and a discharge opening at the top, the sidewalls of the member from the bottom to near the top being provided with a plurality of series of tangential openings in diflerent horizontal planes, means for discharging air through the said tangential openings into the combustion chamber, a nozzle positioned to discharge tangentially into the chamber at the bottom, means for supplying a combustible oil and air mixture to the nozzle, and means for igniting the combustible mixture at the bottom oi. the chamber.

PHILIP S. ARNOLD.