US3144897A

US3144897A - Oil burner apparatus

Info

Publication number: US3144897A
Application number: US70245A
Authority: US
Inventors: Biber Albert; Sr Orvis A Davis
Original assignee: Gulf Research and Development Co
Current assignee: Gulf Research and Development Co
Priority date: 1960-11-18
Filing date: 1960-11-18
Publication date: 1964-08-18
Anticipated expiration: 1981-08-18
Also published as: BE600428A; CH369852A; GB928355A

Description

1964 A B|BER ETAL 3,144,897

OIL BURNER APPARATUS Filed Nov. 18. 1960 2 Sheets-Sheet 1 INVENTORS RVIS A. DAVIS, SR.

LBERT BIBER ATTORNEY 'Aug. 18, 1964 BlBER E 3,144,897

OIL BURNERYAPPARATUS Filed Nov. 18. 1960 2 Sheets-Sheet 2 INVENTORS ORVIS A. DAVIS, SR.

ALBERT BIBER ATTORNEY United States Patent 3,144,897 OIL BURNER APPARATUS Albert Biber, Verona, and Orvis A. Davis, Sn, Gihsonia,

Pa, assignors to Guif Research & Development Company, Pittsburgh, Pa, a corporation of Deiaware Filed Nov. 18, 196i), Ser. No. 70,245 6 Claims. (Cl. 158-28) This invention relates to oil burner apparatus employing an aspirating type nozzle.

The flame produced upon ignition of the spray from a nozzle to which a liquid fuel is pumped under pressure has the general characteristics of being widely dispersed, having a deep yellow coloration and being extremely smoky. In order to produce a flame of improved characteristics from this type of nozzle it is necessary to construct a nozzle having such a restricted orifice that the nozzle generally becomes inoperative due to plugging. On the other hand, a flame of sharply improved characteristics is produced by employing for liquid fuels aspirating type nozzles wherein an aspirating gas such as air or steam but preferably air passes through the nozzle in a manner which creates a suction thereby drawing liquid fuel into the nozzle which admixes with the air to form an atomized fuel-air mixture. In contrast to non-aspirating nozzles, such a nozzle employs relatively large oil passageways while spraying as low as about 0.1 gallon of fuel oil per hour. The air or other gas used to aspirate oil into such nozzles is employed at the low pressure of about 2 to 10 pounds per square inch gauge while the oil is made available to the nozzle at only atmospheric pressure. Advantageously, the oil is drawn into the nozzle from a level lower than the nozzle so that the oil reaches the nozzle purely by the aspirational effect of the air passing therethrough.

Aspirating nozzles for liquid fuel preferably employ a frusto-conical swirl stem possessing slanted peripheral grOOVes and disposed against a corresponding frusto-conical surface inside the nozzle body. The grooves constitute ducts leading into a swirl chamber whereby a swirling motion is imparted to the aspirating air passing therethrough en route to the swirl chamber. The swirl chamber has an axial discharge orifice restriction at the end opposite the swirl stem and an oil inlet duct extends axially into the swirl chamber a portion of the distance from the swirl stem to the discharge orifice. The aspirating air swirling through the swirl chamber draws oil into itself to form a mixture of fuel and air. The air-oil mixture from the swirl chamber is passed through the discharge orifice of the nozzle and upon ignition burns as a compact, elongated flame.

Other constructions can be employed in place of a swirl stem for swirling the aspirating air. For example, the aspirating air can be admitted tangentially to a swirl chamber which is circular in transverse cross section through a wall opening. However, no matter what swirling means is employed, when an axial oil inlet duct is employed it must extend to at least an intermediate point along the length of the swirl chamber or else the aspirating gas will not aspirate suflicient oil into the swirl chamber to form a combustible mixture.

The compact, elongated, high velocity flame from the aspirating nozzle burns with a light yellow coloration. The base of the flame starts at a point just slightly outside "ice the discharge orifice of the nozzle and in the case of a nozzle employing air at about 3 pounds per square inch gauge pressure drawing into the nozzle about 0.15 gallon of oil per hour this flame extends for about 12 inches and averages about 1 to 3 inches in diameter. In accordance with this invention an apparatus has been developed to be employed in combination with such a nozzle for sharply improving the characteristics of the flame.

The apparatus contemplated by this invention when used in combination with an aspirating type nozzle improves the characteristics of the flame in two important respects. The first improvement is the nearly complete elimination of flame or combustion noise whereby the flame from the aspirating nozzle burns at a barely perceptible noise level. The second improved burning characteristic is the alteration of the visible fire from a narrow, elongated light yellow streak to a soft blue flame of generally spherical configuration located in a zone close to the extremity of the elongated type flame which would exist in the absence of the apparatus of this invention. In effect, the apparatus of this invention thereby moves the flame away from the discharge orifice of the nozzle and limits nearly the entire combustion to the region occupied by the very tip of the elongated flame which would exist in the absence of the apparatus. Removal of the flame from the nozzle in this manner serves the important purpose of keeping the nozzle in a cool condition during operation. Moreover, the replacement of a yellow flame with a soft blue flame evidences the realization of substantially complete rather than partial combustion.

The apparatus of this invention comprises a tube preferably cylindrical in shape, an aspirating nozzle having a discharge orifice disposed coaxially with respect to said tube with said discharge orifice directed into the first end of said tube, means at the first end of said tube apart from said nozzle for the admission of air to said tube, barrier means in the region of the second end of said tube, said barrier means being disposed a flame noise reducing distance from said nozzle and exhaust gas passage means at the second end of said tube, preferably between said barrier means and said tube.

It has been discovered that each element of structure recited is essential to the realization of the improved combustion achieved in accordance with this invention when employing an aspirating nozzle. For example, when an aspirating nozzle is directed axially into a tube having a length substantially as great as the length of the flame it is necessary to provide opening means at the nozzle end of the tube for the admission of the air needed to support combustion of the flame and prevent its extinguishrnent. Whereas air is directly charged to the aspirating nozzle to serve as an aspirating gas the quantity of air which passes through the nozzle is only a small fraction of that required for the substantially complete combustion of the amount of oil this air aspirates in its passage through the nozzle. Therefore, to permit ignition and support combustion opening means is necessary at the end of the tube in the region of the aspirating nozzle for the admission of auxiliary air in substantially suflicient quantity for complete combustion. It was further found that the auxiliary air must be introduced at the end of the tube in the region of the aspirating nozzle and cannot be introduced gradually over the entire length of the tube as by employing a perforated rather than a non-perforated tube. The use 3 of a perforated rather than a non-perforated tube totally failed to achieve the silent burning characteristics of the apparatus of this invention.

The combination of the aspirating nozzle, non-perforated tubular member and auxiiiary air passage means in itself had no important effect upon the characteristics of the flame. However, when operating such a combination it was discovered that as a barrier member on a plane transverse to the axis of the nozzle and tube was moved from a distant point into the region of the end of the flame remote from the nozzle, but remaining out of contact with the tube so as to define an exit duct between itself and the tube, a drastic transformation in the nature of the flame occurs. The flame noise is transformed from its normal level and almost completely disappears during movement of the barrier into the flame in a critical region at which impingement of the flame upon the barrier apparently starts to effect substantial gas turbulence. Concurrently with loss of flame noise the shape and color of the flame is altered from an elongated light yellow flame to a flame of spherical configuration having an almost transparent bluish hue centered in the region near the barrier and away from the nozzle.

No comparable effect was achieved by merely moving a barrier member into the tip of a flame from an aspirating nozzle in the absence of the tubular member and auxiliary air source described. In the absence of the tubular member and auxiliary air source, placing a barrier transversely against an aspirating nozzle burner flame at a point along the length of the flame where noise reduction occurs causes the tip of the flame upon striking the barrier to reflect back to the region of the nozzle thereby surrounding base of the flame and depriving it of the auxiliary air necessary for complete combustion. This produces a flame of deep yellow coloration indicating highly incomplete combustion and deposits a heavy layer of soot upon the nozzle in addition to depriving the flame of its elongated configuration.

Observations of flame characteristics such as shape and color when employing the apparatus of this invention were made possible by constructing the tubular member of transparent glass. Such observation indicated that although the barrier member could comprise a flat, solid, metallic sheet, highly superior results are achieved by employing as a barrier a concave or, preferably, a cupshaped member disposed concavely with respect to the flame. The use of a cup-shaped member allows maximum spacing between the tubular duct and the barrier while achieving the desired improvement in flame characteristics, thereby avoiding retardation of gas flow through the system. In contrast, a flat barrier member required deposition so close to the tubular duct to achieve the desired improvement in flame characteristics that an inadequate exit duct for the system resulted.

This invention is illustrated more particularly by reference to the accompanying drawings in which FIGURE 1 illustrates a preferred aspirating nozzle construction to be used in the apparatus of this invention and FIGURES 2, 3, 4 and 5 show the other apparatus elements employed in combination with this nozzle.

Referring to FIGURE 1, a longitudinal cross sectional view of a nozzle designated generally as is shown having a tubular body portion 12 which is internally and externally threaded as shown. The forward end of body portion 12 terminates with a substantially flat integral enclosure 14 which is on a plane transverse to the axis of tubular body 12. Enclosure 14 has an axial tapered central orifice opening 16. Orifice plate 18 immediately inside of and adjacent to enclosure 14 has an over-all diameter less than the internal diameter of tubular body 12 and has an axial orifice 20. Orifice 20 is the apex of an axial conical bore 60 as shown. The diameter of orifice opening 16 is larger than the diameter of orifice opening 29 and a duct 62 extends from orifice 20 to partially obstruct the entrance to orifice 16. The forwardly 1- protruding peripheral rim 22 of orifice plate 18 contains one or more borings 24 which open in a tangential manner into swirl chamber 53 which is formed by virtue of rim 22 setting apart the rearward surface of enclosure 14 and the forward surface of orifice plate 18.

A plug 26 having external threads and an axial bore 28 is equipped with two or more prongs 30 on its rear face so that it can be screwed into the interior of tubular body 12 and urge orifice plate 18 in sealing engagement against the inner surface of enclosure 14 so that orifice opening 29 is axially disposed. Plug 26 has a central forwardly projecting stud 32 terminating with a frustoconical swirl stem 34 which holds orifice plate 18 in place by abutting firmly against the complementary internal surface of the base portion of conical bore 60 leaving unoccupied the apex of conical bore 60, the unoccupied apex of conical bore 60 constituting a swirl chamber 40. Swirl stem 34 is equipped with one or more peripheral slots 36 extending the length of the stem and providing passage between air chamber 33 and swirl chamber 40. Slots 36 are generally comparable in cross section and length with borings 24 so that the pressure drop through each is generally the same. In one example, slots .030 inch square are employed. Bore 2-8 which is coaxial with tubular body 12 constitutes a connecting passageway for the suction of oil from an oil reservoir on a lower level, not shown, into swirl chamber 4-9. Bore 28 is extended through a portion of the length of swirl chamber 40 by means of tube 61.

After the orifice plate 18 is secured in position by tightly screwing plug 26 into place as shown in FIGURE 1, the entire resulting nozzle assembly is secured into position for use by screwing tubular body 12 into end piece 42 of the tubular member shown in FIGURES 2, 3, 4 and 5. After the nozzle is assembled and secured into place, an oil reservoir on a level lower than the nozzle is connected to the nozzle at externally threaded boss 44 extending rearwardly from the center of plug 26 and coaxial with oil passageway 28. Suitable flared tubing 46 extends from below the level of oil in the reservoir and is attached in sealing connection to boss 44 by means of nut 48. Passage of compressed air to chamber 38 is provided by passageway 50 through plug 26 terminating with rearwardly extending externally threaded boss 52 to which flared tubing 54 is attached in sealing connection by means of internally threaded nut 5a.

In operating the nozzle shown in FIGURE 1 air under a pressure between about 2 and 10 pounds per square inch gauge, pressures in the upper portion of this range being employed when it is desired to aspirate greater quantities of fuel oil than are aspirated at air pressures in the lower portion of this range, is charged to air chamber 38 from which it passes through groove 36 and enters swirl chamber 40 substantially tangentially and swirls in swirl chamber 40. The swirling air draws oil from a reservoir which is on a lower level than the nozzle by suction through passageway 23 into swirl chamber 40 where a fuel-air mixture is formed which passes through orifice 20 and duct 62 to a second orifice 16. Tube 61 allows the air to assume an adequate swirling pattern prior to aspirating in oil and prevents air back pressure against the oil from the reservoir. Secondary air from air chamber 38 passes through tangential inlet ducts 24 to second swirl chamber 58 from which it swirls through orifice 16 where it increases in velocity and aspirates into itself the fuel-air mixture from duct 62 to form a new iixture in which the oil is more highly atomized and which is richer in air. The new mixture is discharged in a swirling pattern through orifice opening 16.

It has been found that ducts 61 and 62, which project axially a portion of the distance into each swirl chamber, are essential to operation of the nozzle and in the absence of either or both of these ducts the air was unable to aspirate suflicient oil into inself to create a mixture of oil and air capable of sustaining combustion.

Referring to FIGURE 2, nozzle is shown disposed coaxially with and at one end of hollow tube 70 with its discharge orifice 16 facing into the tube. An ignitor, not shown, can be disposed near orifice 16. The ignitor can be of the sparking type or of any other electrical or nonelectrical type capable of kindling the spray from orifice l6. Tube 70 is shown in its preferred cylindrical shape but it may be of another shape, for example, it may be of elliptical or rectangular transverse cross section. Tube 70 is shown as being enclosed at the nozzle end by means of an end piece 42 to which nozzle 10 is secured. The nozzle is supplied with fuel oil from reservoir 47 by means of conduit 46 and with aspirating air by means of conduit 54 from header 72. Header 72 also supplies air to chamber 74 through conduit 76. Alternately, chamber 74 can be supplied with ambient air. Air chamber 74 has an open top which abuts in sealed engagement with end 42 of tube 70 and the top of chamber 74 encompasses a plurality of perforations 78 surrounding nozzle 10. As is indicated in both FIGURE 2 and FIGURE 3, air chamber 74 has access to the interior of tube 70 only through perforations 78 which extend through end piece 42 in the region thereof relatively close to the longitudinal axis of tube 7% while the region of end piece 42 relatively close to the wall of tube 70 as well as the region of the wall of tube 70 itself are free of perforations or other means through which air could enter tube 70 during burner operation.

The top end of tube 70 has a cup-shaped barrier 86 secured in spaced relation to it by means of brackets 82. The cup-shaped barrier 80 is inverted so that rim 84 is the portion of barrier 8th closest to tube 70. In place of cup-shaped barrier 80 a flat solid plate type of barrier can be employed such as barrier 92 shown in FIGURE 3. However, as shown in FIGURE 3 a flat solid type of barrier would have to be disposed much closer to the top of tube 70 thereby substantially reducing the exit opening defined between the barrier and tube 70.

The apparatus shown in FIGURE 2 contains all the essential elements of structure required to achieve the beneficial results of this invention. However, improved operation of the apparatus of this invention is achieved by employing a shield 86 which is a screen as shown in FIGURE 3. The shield 36 is disposed within and transverse to the axis of tube 70 intermediate the barrier 92, which is also transverse to the axis of tube 70, and the nozzle It Shield 36 is coaxial with tube 70 and has a central opening 36 providing an unobstructed path for the flame from nozzle 10 to barrier 92. Shield 86 provides two important functions by means of preventing reflection of the flame upon impingement at barrier 92 back to the nozzle. These are insuring the flame of the air it requires for substantially complete combustion and maintaining a relatively cool nozzle.

As previously noted when a fiat plate barrier, such as barrier 92 in FIGURE 3, is employed it is necessary that it be disposed much closer to the tube 70 than the inverted cup type of barrier 80 shown in FIGURE 2. It is especially important that shield 86 be employed when the barrier must be disposed so close to tube 70 that the combustion gases exit passageway becomes severely restricted. In the embodiment shown in FIGURE 3 it was necessary to move the flat barrier 92 so close to the nozzle 10 in order to achieve flame noise reduction that the barrier 92 is of smaller diameter than tube 70 allowing its insertion into tube 70 while still maintaining exit passage means between itself and tube 70. In the event that the clearance between barrier 92 and tube 70 provides insufiicient passage means for the exhaust gases, peripheral slots 94 on tube 769 just below barrier 92 are provided.

FIGURE 3 also shows the use of a perforated tube 90 disposed about nozzle 10. The diameter of perforated tube 9 0 is such that at least a portion of the auxiliary air entering the interior of tube 70 through the plurality of openings 78 rises along the outside surface of perforated tube 99 so that the aspiration etfect of the spray on the inside of the perforated tube tends to draw in through the perforations air required for combustion. Such inflow of air through the perforations of tube tends to make the spray more compact and tends to contain in the spray particles of liquid oil which otherwise would escape, thereby generally improving operation of the apparatus. It is noted that while shield 36 and perforated tube 99 are shown operating together their effects are independent and each can be employed in the absence of the other.

The barrier means in the burner of this invention can take many advantageous forms. As shown in FIGURE 4 the barrier 96 is in the form of an inverted saucer having a brim 1% of substantially the same diameter as the tube 7% and resting coextensively upon the upper edge of tube 70. The side portion of barrier 96 contains a plurality of perforations 98. Still another barrier means is shown in FIGURE 5 wherein the barrier consists of an inverted cup N2 of greater diameter than tube 7% but having an inturned lip 14M at its brim to provide an opening of approximately the same diameter as the cylinder 70. The top of inverted barrier 1G2 is provided with a plurality of peripheral perforations 1%.

Various changes and modifications may be made without departing from the spirit of this invention and the scope thereof as defined in the following claims.

We claim:

1. An oil burner apparatus comprising a tubular wall having an inlet end and an exhaust end, enclosure means for enclosing the inlet end of said tubular wall, an aspirating nozzle adapted so that the passage of pressurized primary air therethrough aspirates liquid fuel existing under substantially atmospheric pressure to produce an atomized primary air-liquid fuel spray, said nozzle disposed at the inlet end of said tubular wall coaxially therewith and positioned for directing said spray along a path close to the longitudinal axis thereof towards said exhaust end, barrier means providing axial obstruction at said exhaust end, exhaust passageway means at said exhaust end in the region of said brrier means, said exhaust passageway means constituting substantially the only means for removal of exhaust from said apparatus during combustion of said spray, inlet passageway means through said inlet end enclosure means, said inlet passageway means extending through said enclosure means in a region relatively close to said nozzle and relatively remote from the tubular wall, said inlet passageway means adapted for the admission of secondary air to said apparatus relatively close to the longitudinal axis thereof and relatively remote from said tubular wall, the region of said tubular wall and the region of said inlet end enclosure means relatively close to said tubular wall and relatively remote from said longitudinal axis being free of any inlet passageway means so that said inlet passageway means constitutes substantially the only means for the admission of secondary air within said tubular wall during combustion of said spray, said apparatus adapted so that the flame produced upon combustion of said spray is axially removed from the nozzle and is substantially confined to a region axially remote therefrom.

2. An oil burner apparatus comprising a tubular wall having an inlet end and an exhaust end, enclosure means for enclosing the inlet end of said tubular wall, an aspirating nozzle adapted so that passage of pressurized primary air therethrough aspirates liquid fuel existing under substantially atmospheric pressure to produce an atomized primary air-liquid fuel spray, said nozzle disposed at the inlet end of said tubular wall coaxially therewith and positioned for directing said spray along a path close to the longitudinal axis thereof towards said exhaust end, concave barrier means providing axial obstruction at said exhaust end, said barrier means being concave towards said exhaust end, exhaust passageway means at said exhaust end in the region of said barrier means, said examass? haust passageway means constituting substantially the only means for removal of exhaust from said apparatus during combustion of said spray, inlet passageway means through said inlet end enclosure means, said inlet passageway means extending through said enclosure means in a region relatively close to said nozzle and relatively remote from the tubular wall, said inlet passageway means adapted for the admission of secondary air to said apparatus relatively close to the longitudinal axis thereof and relatively remote from said tubular wall, the region of said tubular wall and the region of said inlet end enclosure means relatively close to said tubular wall and relatively remote from said longitudinal axis being free of any inlet passageway means so that said inlet passageway means constitutes substantially the only means for the admission of secondary air within said tubular wall during combustion of said spray, said apparatus adapted so that the flame produced upon combustion of said spray is axially removed from the nozzle and is substantially confined to a region axially remote therefrom.

3. An oil burner apparatus comprising a tubular wall having an inlet end and an exhaust end, enclosure means for enclosing the inlet end of said tubular wall, an aspirating nozzle adapted so that the passage of pressurized primary air therethrough aspirates liquid fuel existing under substantially atmospheric pressure to produce an atomized primary air-liquid fuel spray, said nozzle disposed at the inlet end of said tubular wall coaxially therewith and positioned for directing said spray along a path close to the longitudinal axis thereof towards said exhaust end, barrier means providing axial obstruction at said exhaust end, exhaust passageway means at said exhaust end in the region of said barrier means, said exhaust passageway means constituting substantially the only means for removal of exhaust from said apparatus during combustion of said spray, inlet passageway means through said end enclosure means, said inlet passageway means extending through said enclosure means in a region relatively close to said nozzle and relatively remote from the tubular wall, said inlet passageway means adapted for the admission of secondary air to said apparatus relatively close to the longitudinal axis thereof and relatively remote from said tubular wall, means for supplying pressurized air to said inlet passageway means, the region of said tubular wall and the region of said inlet end enclosure means relatively close to said tubular wall and relatively remote from said longitudinal axis being free of any inlet passageway means so that said inlet passageway means constitutes substantially the only means for the admission of secondary air within said tubular wall during combustion of said spray, said apparatus adapted so that the flame produced upon combustion of said spray is axially removed from the nozzle and is substantially confined to a region axially remote therefrom.

4. An oil burner apparatus comprising a tubular wall having an inlet end and an exhaust end, enclosure means for enclosing the inlet end of said tubular wall, an aspirating nozzle adapted so that passage of pressurized primary air therethrough aspirates liquid fuel existing under substantially atmospheric pressure to produce an atomized primary air-liquid fuel spray, said nozzle disposed at the inlet end of said tubular wall coaxially therewith and positioned for directing said spray along a path close to the longitudinal axis thereof towards said exhaust end, barrier means providing axial obstruction at said exhaust end, exhaust passageway means at said exhaust end in the region of said barrier means, said exhaust passageway means constituting substantially the only means for removal of exhaust from said apparatus during combustion of said spray, screening shield means having a central opening disposed coaxially within the said tubular wall intermediate said nozzle and said barrier means, inlet passageway means through said end enclosure means, said inlet passageway means extending through said enclosure means in a region relatively close to said nozzle and relatively remote from the tubular wall, said inlet passageway means adapted for the admission of secondary air to said apparatus relatively close to the longitudinal axis thereof and relatively remote from said tubular wall, the region of said tubular wall and the region of said inlet end enclosure means relatively close to said tubular wall and relatively remote from said longitudinal axis being free of any inlet passageway means so that said inlet passageway means constitutes substantially the only means for the admission of secondary air within said tubular wall during combustion of said spray, said apparatus adapted so that the flame produced upon combustion of said spray is axially removed from the nozzle and is substantially confined to a region axially remote therefrom.

5. An oil burner apparatus comprising a tubular wall having an inlet end and an exhaust end, enclosure means for enclosing the inlet end of said tubular wall, an aspirating nozzle adapted so that the passage of pressurized primary air therethrough aspirates liquid fuel existing under substantially atmospheric pressure to produce an atomized primary air-liquid fuel spray, said nozzle disposed at the inlet end of said tubular Wall coaxially therewith and positioned for directing said spray along a path close to the longitudinal axis thereof towards said exhaust end, concave barrier means providing axial obstruction at said exhaust end, said barrier means concave towards said tubular wall, exhaust passageway means at said exhaust end in the region of said barrier means, said exhaust passageway means constituting substantially the only means for removal of exhaust from said apparatus during combustion of said spray, screening shield means having a central opening disposed coaxially within the said tubular wall intermediate said nozzle and said barrier means, inlet passageway means through said end enclosure means, said inlet passageway means extending through said enclosure means in a region relatively close to said nozzle and relatively remote from the tubular wall, said inlet passageway means adapted for the admission of secondary air to said apparatus relatively close to the longitudinal axis thereof and relatively remote from said tubular wall, the region of said tubular wall and the region of said inlet end enclosure means relatively close to said tubular wall and relatively remote from said longitudinal axis being free of any inlet passageway means so that said inlet passageway means constitutes substantially the only means for the admission of secondary air within said tubular wall during combustion of said spray, said apparatus adapted so that the flame produced upon combustion of said spray is axially removed from the nozzle and is substantially confined to a region axially remote therefrom.

6. An oil burner apparatus comprising a tubular wall having an inlet end and an exhaust end, enclosure means for enclosing the inlet end of said tubular wall, an aspirating nozzle adapted so that passage of swirling pressurized primary air therethrough aspirates liquid fuel existing under substantially atmospheric pressure to produce an atomized primary air-liquid fuel spray, a pressurized primary air source and first conduit means between said primary air source and said nozzle, a reservoir containing oil under atmospheric pressure and second conduit means between said reservoir and said nozzle, said nozzle disposed at the inlet end of said tubular wall coaxially therewith and positioned for directing said spray along a path close to :the longitudinal axis thereof towards said exhaust end, barrier means providing axial obstruction at said exhaust end, exhaust passageway means at said exhaust end in the region of said barrier means, said exhaust passageway means constituting substantially the only means for removal of exhaust from said apparatus during combustion of said spray, inlet passageway means through said end enclosure means, said inlet passageway means extending through said enclosure means in a region relatively close to said nozzle and relatively remote from the tubular wall, said inlet passageway means adapted for the admission of secondary air to said apparatus relatively close to the longitudinal axis thereof and relatively remote from said tubular wall, the region of said tubular Wall and the region of said inlet end enclosure means relatively close to said tubular Wall and relatively remote from said longitudinal axis being free of any inlet passageway means so that said inlet passageway means constitutes substantially the only means for the admission of second ary air within said tubular Wall during combustion of said spray, said apparatus adapted so that the flame produced upon combustion of said spray is axially removed from the nozzle and is substantially confined to a region remote therefrom.

References Cited in the file of this patent UNITED STATES PATENTS Rice Feb. 21, Van Zandt Nov. 26, Kittel Feb. 10, Kraus Oct. 11, Parker et a1. Feb. 23, McCollum Nov. 2, Hunter et a1 Mar. 10,

Claims

1. AN OIL BURNER APPARATUS COMPRISING A TUBULAR WALL HAVING AN INLET END AND AN EXHAUST END, ENCLOSURE MEANS FOR ENCLOSING THE INLET END OF SAID TUBULAR WALL, AN ASPIRATING NOZZLE ADAPTED SO THAT THE PASSAGE OF PRESSURIZED PRIMARY AIR THERETHROUGH ASPIRATES LIQUID FUEL EXISTING UNDER SUBSTANTIALLY ATMOSPHERIC PRESSURE TO PRODUCE AN ATOMIZED PRIMARY AIR-LIQUID FUEL SPRAY, SAID NOZZLE DISPOSED AT THE INLET END OF SAID TUBULAR WALL COAXIALLY THEREWITH AND POSITIONED FOR DIRECTING SAID SPRAY ALONG A PATH CLOSE TO THE LONGITUDINAL AXIS THEREOF TOWARDS SAID EXHAUST END, BARRIER MEANS PROVIDING AXIAL OBSTRUCTION AT SAID EXHAUST END, EXHAUST PASSAGEWAY MEANS AT SAID EXHAUST END IN THE REGION OF SAID BARRIER MEANS, SAID EXHAUST PASSAGEWAY MEANS CONSTITUTING SUBSTANTIALLY THE ONLY MEANS FOR REMOVAL OF EXHAUST FROM SAID APPARATUS DURING COMBUSTION OF SAID SPRAY, INLET PASSAGEWAY MEANS THROUGH SAID INLET END ENCLOSURE MEANS, SAID INLET PASSAGEWAY MEANS EXTENDING THROUGH SAID ENCLOSURE MEANS IN A REGION RELATIVELY CLOSE TO SAID NOZZLE AND RELATIVELY REMOTE FROM THE TUBULAR WALL, SAID INLET PASSAGEWAY MEANS ADAPTED FOR THE ADMISSION OF SECONDARY AIR TO SAID APPARATUS RELATIVELY CLOSE TO THE LONGITUDINAL AXIS THEREOF AND RELATIVELY REMOTE FROM SAID TUBULAR WALL, THE REGION OF SAID TUBULAR WALL AND THE REGION OF SAID INLET END ENCLOSURE MEANS RELATIVELY CLOSE TO SAID TUBULAR WALL AND RELATIVELY REMOTE FROM SAID LONGITUDINAL AXIS BEING FREE OF ANY INLET PASSAGEWAY MEANS SO THAT SAID INLET PASSAGEWAY MEANS CONSITUTES SUBSTANTIALLY THE ONLY MEANS FOR THE ADMISSION OF SECONDARY AIR WITHIN SAID TUBULAR WALL DURING COMBUSTION OF SAID SPRAY, SAID APPARATUS ADAPTED SO THAT THE FLAME PRODUCED UPON COMBUSTION OF SAID SPRAY IS AXIALLY REMOVED FROM THE NOZZLE AND IS SUBSTANTIALLY CONFINED TO A REGION AXIALLY REMOTE THEREFROM.