US1822844A - Apparatus for burning liquid fuel - Google Patents

Description

Sept. 8, 1931. A. L.. KLEEs APPARATUS FOR BURNING LIQUID FUEL Original Filed Feb. 15, 1926 l Patented Sept. 8, 1931 UNITED ALBERT `L. KLEES, F NEW YRK, N. Y., ASSIGNRTO COMBUSTION UTILITIES CORPO- BATION, 0F YORK, N. Y., A CORPORATIDN 0F MAINE Arramrus ron summe LIQUID :FUEL

Original application led February 15, 1926, Serial No. y588,196'. Divided and this yapplication led December 2, 1927.

, copending application Ser.No.,88-,196 filed Feb. 15,* 1926, which has resulted in Patent No. 1,740,249 issued December 17, 1929, of which this is a divisional application.

The combustion of oil or other liquid fuel is ordinarily accomplished in domestic heating furnaces by atomizing a jet of the oil with air or steam under pressure into the combustion chamber of'a furnace through a small orifice Ilozzle, and igniting the a1ror. 1

steam-oil mixture by contacting it with the flame from a gas pilot light or other source of heat as it leaves the tip of the nozzle. It

has been proposed to operate furnaces for heatin houses or the like with gas as the' normal load fuel and to supplement the gas with oil during periods in which the demand for heat is greater than can be readily taken care of by the amount of gas available. Ac-` cording to this proposed system the air-oil mixture issuing Afromthe atomizing nozzle is ignited and rapidly vaporized by heat supplied from the flame of a gas burner of relatively much greater heating power than that furnished by the ordinary pilot light. Accordingly with a combination gas and oil. burner such as that suggested it is possible to burn a relatively much cheaper grade of oil than can be used in,.the ordinary type of burner, burning oil only.. .It has been found,

- however, that the combustion of oil in a furnace either equipped withthe common type of oil burner or with a gas-oil burner such as that suggested is generally accompanied by a ilickeringame and a roaring noise of varying intensity which is very objectionable and disturbing to the householder.

The primary object of the present invention is to provide an improved apparatus for i effecting the combustion `of oil in house heating furnaces without any objectionable combustion miis. l A furtheri'objec't 'of the invention 1 s to pro- Serial No. 237,187.

yide apparatus for burning oil in house heating furnaces with a smoother and more efficient flame than thatcommonly produced with the ordinary type of oil or oil-gas burner above referred to.

With these and other objects in view the `invention consists in the improved apparatus for burning liquid fuels hereinafter deuscribed. and particularly defined in the claims. v

The various features of the invention are illustrated in the accompanying drawings, in which L Fig. 1 is a view in elevation, partly insectionkof a standard type of domestic heating furnace'equipped with an `improved gas-oil burner apparatus of the type embodying the preferred form of the present invention.

Fig. 2 is a vertical section of the oil atomizing nozzle illustrated in Fig. 1; and `Fig. 3 isaplan view with parts cut away showing the relative arrangement ofthe gas burner and oil atomizing lnozzle, taken on line 3-',3 of Fig. 1. The basic principle underlying the present invention has been evolved as the result of a large number of experiments carried out to determine the source of the considerable amount of,noise produced when an air-oil mixture is injected under pressure into the combustion chamber of a house heating furnace and is ignited as it leaves the tip of the rate of .dame propagation of the atomized 'air-oil mixture:

Accordingly one feature of the present invention contemplates a new design of gasoil burner having the gas burner so arranged relative to the oil atomizing nozzle that the' ignition of the atomized oil `air mixture enteriug the combustion chamber will be ef ratus 12 in the furnace the coal burning grates with which the furnace may be originally equipped are removed and a cast or sheet metal cone frustum 14 is placed in the furnace with its base resting on the lugs or rings 16 ordinarily used to support the grate. The cone 14 is centrally apertured to permit the flame issuing from an oil atomizing nozzle 18 to project into the lower part of the furnace without coming into contact with any solid surface. Apparatus 12 isV mounted in the lower portion of the furnace at one end of flue 20 which extends into the ashpit 22 of the furnace 10 through the doorway ordinarily used for removing ashes.

The burner apparatus 12 comprises an annular gas burner 24, preferably cast as an integral part of the cone 14, and the oil atomizing nozzle 18, mounted centrally of the gas burner and in a horizontal lane vertically spaced a substantial distance elow the plane of the gas burner. The gas burner 24 includes a large number of individual burner tips 26 extending in a ring around its inner e ge with their bores directed horizontally and radially toward the central aperture of the burner, so that flames issuing from tips 26 lie in a position to strike the edge of and be drawn at right angles into a jet of atomized oil issuin from the centrally positioned oil nozzle 18. g1`he cone 14 entirely surrounds and extends upwardly a short distance above the level of the burner tips 26. Resting on brackets 28 on the upper edge of cone 14 is a spider 30y supporting a central plate or button 32, preferably made of cast iron and centrally posltioned in the furnace so as to contact with and spread oil fiame issuing from the nozzlev 18, to promote the thorough mingling of the oil and oil flame from nozzle 18 with the gas and gas flame from burner 24.

In accordance with the present invention an ideal apparatus arrangement for burning heavy fuel oil is provided by burning gas within a-refractory cone to maintain a radiating surface which will-readily ignite and vaporize even the heaviest grades of fuel oil. The burner is preferably so operated that at the time oil is introduced into 'the furnace through the nozzle 18, the gas from burner 24 will be burning at itsv maximum. Therefore the oil is introduced into a heated chamber and into a burning gas flame, thus insuring its complete combustion. The means for supplying gas and air to burner 24 form no part of the present invention and accordingly are lllustrated only diagrammatically in the drawings.

A pipe 34 is Shown, preferably connectedV zle 40. The gas flowing through nozzle 40 draws primary air in around the edges of conduit 42 through passages 44 and the air and gas after mixing in conduit 42 pass into the burner 24. In order that the flame of the gas burner may be `regulated as desired, a cap or shutter 46 is movably mounted on a threaded section of the nozzle 40. When moved up against the end of conduit 42 this shutter closes the air passages 44 and shuts off the flow of air into the mixing chamber. Therefore by screwing the cap 46 back and forth on nozzle 40 the flow of air and gas to the burner 24 may be regulated as desired and the position of cap 46 maybe so adjusted with respect to the amount of opening-of a valve 48 in gas supply line 34 that any desired percentage mixture of gas and air is admitted to conduit 42 and burner 24. Sufficient secon'dary air for burning the gas, in case no oil is entering the furnace, will leak in through small openings around the base of the furnace and Hue 20, and when oil is being supplied to the furnace additional air will be almitted in a manner hereinafter described. If the burner apparatus is a part of a house heating system the hand valve 48 on the gas line may be preferably replaced by a snap valve of some sort, together with automatic means for operating the valve in accordance with the call for heat registered by a thermostat in some part of the house (not shown).

The means for supplying oil to the nozzle 18 and the means for starting and stopping the flow of oil form no part of the present invention and accordin ly are merely indiloe" cated diagrammatically 1n the drawings. Oil

from a storage tank or other'source of supply is preferably raised by pump suction to an oil pump 50Vthrough a pipe 52 and 'is forced by the pump to nozzle 18 through a pipe 54. Any excess oil handled by the pump and not needed at the burner is by-l passed to a tpipe 55 andreturned to Stora e. The type o oil pump 50 illustrated in t e drawings is of thevalveless oroscillating rotor type. As indicated in the drawings the pump 50 is mounted in alignment with the drive shaft of an electric motor 56 which is,y energized through a circuit 58. Intermediate oil pump 50 and motor 56 is a pump 60'fur- Leaaeaa nishing air under pressure for atomizing oil delivered by pump 50 at the nozzle 18. The casing of air pump 60 is fixed to the casing or motor 56 and oil pump 50 has its-shaft in alignment with those of the motor and oil pump. The motor and pumps 50 and 60 form a unitary structure. Air pump 60 receives air through an' inlet 61 and delivers it through a pipe 62, supported in flue 20, to the atomizing nozzle 18. Though not illustrated, thermostatic control switches' are preferably employed in the circuit of motor 56 for the purpose of automatically starting and stopping the oil pump 50 and blower 60 in accordance with the heat requirements on the furnace 10. Likewise the pilot 38 is equipped with a coil 64 of a vapor-stat or similar Huid control which will operate, upon the extinction of the flame of the pilot, preferably on a fluid motor controlled switch opening the circuit to motor 50 and also on a snap valve or other device cutting off the supply of gas to burner 24 (not shown). A similar device 66 positioned on the top of the furnace may be employed to interrupt the circuit of motor 56 and thus shut down the motor and oil pump 50 wheneverl the temperature of the furnace or the pressure on the boiler exceeds certain desired limits. These various automatic safety devices form no part of the present invention and accordingly have not been fully illustrated and will not be more completely described in connection with the present case.

As already indicated, primary air for atomizing and burning the oil is supplied by pump 60 through pipe 62 to the atomizing nozzle 18. A relief valve 68 near the head of pipe 62 affords the means both for proportioning the amount of air to oil supplied to nozzle 18 and also for regulating the pressure built up in line 62 and the resultant velocity with which the atomized oil-air mixture issues into the furnace from the tip of nozzle 18. For the purpose of supplying additional secondary air to burner apparatus 12 when oil as well as gas is being burned an air inlet aperture 70 is provided in flue 20, aperture 70 being closed by a damper 72 except when oil is being burned. Damper 72 is hinged at 74 to the inside of the bottom surface of flue 20, so that the damper remains normally closed by reason of its own weight. In order to open damper 72 when needed, link 76 is connected to the unhinged part of the damper. At its opposite end link 76 is connected to a flexible operating diaphragm 78. Diaphragm 78 is rigidly held in place by the two sections of casing 80 so as to form a tight closurey for a chamber 82 in the lower portion of the casing. A pipe 84 connects the interior of primary air supply line 62 with the interior of chamber 82 beneath diaphragm 7 8. With this arrangement the same air pressure is maintained` in chamber 82 that exists in pipe 62. Therefore when the air pump 60 is put into operation the diaphragm 78 will be automatically raised and the damper 72 will be opened to admit secondary air into flue 20.

As a result of a large number of tests made with the present burner apparatus, using many classes of oil fuels injected into a furnace at the relatively low atomizing air pressure, it has been determined that' a condition of substantially noiseless combustion with a correspondingly high degree of combustion efficiency can be maintained in the furnace when the gas burner 24 is elevated a distance approximating 4 above the tip of oil nozzle 18. In other words it has been found that by adjusting the volume of air passed by blower 60 to oil burner 18 by means of valve 68 in accordance with the type of oil fuel being burned the same relative setting of the gas burner and oil nozzle may be used when burninga wide variety of oils in the furnace without producing any undesirable amount of combustion noise. -Thus the valve 68 can be adjusted to change the proportions of air and oil and to vary the velocity of the oil-air mixture issuing fromc the tip of nozzle 18 to maintain the point of ignition of the oil-air mixture constant at approximately Athe desired point at which the velocity of the jet issuing from the nozzle has attained a value equal tothe rate of flame propagation of the various air and oil mixtures fired. l.

In order to provide for different fuel conditions, means are provided for securing a positive adjustment of the distance separating the tip ofnozzle 18 from the plane of burner tips 26. 'Ifhe device illustrated in the drawingtconsists essentially of a small jack screw arrangement 86 which is shown posil tioned under the base of nozzle 18. By rotating a worm 88 a rotary movement may be imparted to a pinion 90. The bore of pinion 90 is threaded so that by Iits rotation it raises or lowers a threaded plunger 92. The head of plunger 92 is positioned to carry the weight of nozzle 18 and by the movement of the plunger it is possible to raise or lower the nozzle through a short distance which, though limited by the angle through which it is safe to swing the pipes 62, 54 an-d 84, is still sufficient in conjunction with the alternate adjustment afforded by valve 68 to give a wide range of adjustment to the burner apparatus and thus afford the means for insuring noiseless combustion while burning a wide vvariety of fuel oils. In order to hold the nozzle 18 in a central position in the furnace, brackets 94, attached to the base of cone 14, extenddownwardly and form with their ends a sleeve the nozzle casing from pipe 54 through a chamber 96, the top of which is formed into acap 98. The air for atomizing the oil enters a chamber 100, into. which is threaded the pipe 62 leading from air pump 60. From chamber 100 the air passes upwardly through a nipple 102 into an annularA opening 104 surrounding a nozzle 106. A pipe 108 is threaded in cap 98 and runs centrally through chamber 100 and nipple 102, to conduct oil into the bore of burner nozzle 106. A protecting cap 110 may if desired be screwed onto threads on the casing of nozzle 18. The upper end of nipple 102 tapers at r'an angle toward an aperture 112 in nozzle 106, thoe inner tip of the nipple being spaced from the nozzle so that air may pass up around the outside of the nozzle through an annular aperture 114. Oil is delivered through the pipe 108 and the interior bore of) nozzle 106 to the aperture 112 so that air and oil are immediately and thoroughly commingled as they issue from the apertures 112 and 114A respectively.

The operation of the apparatus according to the present invention may be briefly summarized as follows: During periods of normal temperature only the pilot burner 38 is left burning. As the temperature begins to fall the gas valve 48 is opened and cap 46 at the head pf conduit 42 is adjusted to admit suitable proportions of gas and air to burner 24. When the maximum supply of gas has been reached the electric circuit of motor 56 is closed and the oil pump and air pump 60 will be simultaneously set in operation to supply oil and air under pressure to nozzle 18. Before the oil pump starts up the cone 14 will have become highly heated by reason of the combustion of gas issuing from the tips of burner 24, so that when the oil is introduced into the furnacefrom nozzle 18 it will be atomized into the gas flame from burner 24 and into the highly heated chamber formed by cone 14. When the oil pump is started by moto;` 56 the damper 7 2 in flue 20 is graduall opened as the air pressure in pipe 62 bullds up. This furnishes the secondary air for ythe loil and gas flame supplied by burner apparatus 16. The oil and gas continue to burn in the furnace until the heat supplied by the boiler is sufficient to raise the temperaturein the house to normal, at which time the circuit to the motor 56 will be broken, ,preferably automatically, and the motor, oil pumpl and blower will stop. If the temperature continues to rise the supply of gas to burner 24 can be cut off by closing Valve 48.

As previously indicated, the hand valve 48 illustrated in the drawings may be replaced by a snap valve of some sort with automatic means for controlling the operation of such valve and the supply of gas to burner in accorda-nce with the call for heat registered by a thermostat.

As previously pointed out, prior designs of oil and gas-and-oil burning domestic furnaces are so arranged that the pilot flame or other source of :ignition is applied to the atomized oil-air mixture atthe instant it enters the combustion chamber from the atomizing nozzle. Consequently in operating these burners an unstable condition of combustion is commonly present at the source of ignition and the oil flame which is produced continually bucks and flickers and generates a considerable amount of roaring noise. According to the present design an elevated source of ignition is used, spaced at exactly the proper distance from the tip of the oil burner so that the velocity of the atomized oil-air mixture is substantially equal to the rate of flame propagation of the mixture at the instant combustion begins. At this point the cross-sectional area of the air-oil Jet is .many times larger than the area at the base Consequently the mixture can be of the jet. much more readily ignited and combustion will maintain itself at this point Without any appreciable amount of bucking or flickering. By employing a gas burner which entirely surrounds the jet of o il and air issuing from 'the oil' burner, the gas flame thrown out from the tips of the gas burner spreads in a substantially horizontal sheet over the entire cross-section of the jet of combustible oil and air mixture issuing from the atomizing nozzle, igniting the mixture throughout the entire cross-section of the jet rather than at a few points in the periphery, as is now the common practice. In other words the ignition of the air-oil jet according to the present invention is effected uniformly throughout its entire cross-section yat an elevation where the mixture vis prepared to maintain its combustion without any flickering back and forth, producing practically lnoiseless combustion with a smooth andvmost desirable characterof flame. Moreover, because combustion takes place in a smooth'and effective manner the highest degree of efficiency in the combpstion of the oil fuel is obtained' with" a minimum amount of over-ventilation.

'115 Another advantage of using the elevated' gas burner is that .the heat of the'gas flame is not thrown into the atomized mixture until' f' tion and has spread over-a relatively large cross section. Throwing the heat of the gas the oil has reached a finestate of atomizafire into intimate contact with the finely atomized oil at ..this point Agives the burning'l gas a better opportunity to further break up the oil s ray 'and to completely vaporize the atomize i oil, thereby producing efficientI combustion without any possibilityof car--- bon formation. 'In other words by igniting the atomized mixture at the critical point at which the velocity of the jet entering the Lezama bon or surface combustion such as usually occurs with the common type of. oil burner apparatus.

It is not intended by the foregoing description to limit the invention to the use of air as an atomizing agent for the oil or other liquidfuel, since obviously steam or other suitable atomizing agent for the liquid fuel may be employed without departing from the principle underlying the invention. v

The term pre-mixing type gas burner9 has been used in the claims as a generic term to define that type of gas burner embodying in its structure a mixing tube or chamber wherein pre-mixing of the primary air and combustion gas takes place before the gas exits from the burner ame orifice or tip.

The invention having een thus described, what is claimed as new is: l j y 1. The combination withn a heating furnace, of a liquid fuel burner, asource of ignition spaced from said burner and ar` ranged to throw a sheet of flame across the flow area of the atomized fuel vented from said burner, and means `for adjusting the spacing between the discharge orifice of the burner and said source of ignition to 'maintainthe velocity of the jet of atonized-fuel entering the furnace substantially. equal to the rate of flame propagation of the airfuel mixture at the point of ignition.

2. The combination with a heating furnace', of a pre-mixing type gas burner adapted to form a ring of gas flame within the combustion chamber of said furnace.r and an oil'burner so arranged with respect to said gas burner as to throw a iet of atomized oil within said ring of 'gas flame at a velocity substantially equal to the rate of flame propagation of the ignited air-oil mixture.

3. The combination with a heating furnace of a pre-mixing type gas burner arranged vto throw a sheet of gas flame across sthe lower portion of said furnace, an atomizlng nozzle spaced from said gas burner and arranged to throw a jet' of atomized oil within said dame.,

burner to enter the furnace without coming l l linto contact with any solid surface.

5. rlhe combination with aheating furnace of a radiating body mounted in said. furnace and centrally apertured to kenclose a premixing type gas burner, said gas burner being so arranged as to throw a sheet of gas flame transversely across said aperture, and an oil burner adjustably spaced from said gas burner and arranged to throw a jet of atomized oil axially of'said aperture through said sheet of gas flame.

6. The combination with a heating furnace of a ring shaped pre-mixing type gas burner and an oil burner spaced from and mounted co-axially with respectto the aperture formed by said gas burn-er, means for supplying a combustible mixture to said gas burner, and means for adjusting the ratio of air to oil supplied to said oil burner in accordance with the grade of oil being fired and the space` separating the vent orifice in the oil burner from thering of gas flame produced by said gas *burner* to maintain substantially uniform and quiet combustion in said furnace.

7. The combination with a ring-shaped pre-mixing type gas burner adapted toform a ring of gas flame, of an oil burner having the tip of its atomizing nozzle spaced about four -inches from the center of said gas burner in position to throw a jet of atomized oil approximately through. the center of said ring of gas flame.

ln testimony whereof l affix'my signature.

ALBERT L. KLEES.

ica

and means for adjusting the space separating of an oil burner, al heat radiating surface of annular cross section disposed co-axially in front of said oil burner, a plurality of pre-

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