US2905234A - Apparatus for the combustion of liquid fuels - Google Patents

Description

Sept. 22, 1959 H. SCHOLZ 2,905,234

APPARATUS FOR THE COMBUSTION of LIQUID FUELS Filed Feb. 17, 1956 5 Sheets-Sheet 1 INVENT OR 1: Hm SC/lOZiZ ATTORNEYS H. SCHOLZ Sept. 22, 1959 APPARATUS FOR THE COMBUSTION OF LIQUID FUELS Filed Feb. 17, 1956 5 Sheets-Sheet 2 INVENTOR H/MU SCHOLZ ATTORNEYS H. SCHOLZ Sept. 22, 1959 APPARATUS FOR THE COMBUSTION OF LIQUID FUELS Filed Feb. 17, 1956 5 Sheets-Sheet 3 IIIIIIIIIIIII v 1 HANS SCHOLZ NVENTOR ATTORNEYS Sept. 22, 1959 H. SCHQLZ 2,905,234

APPARATUS FOR THE COMBUSTION OF LIQUID FUELS Filed Feb. 17, 1956 5 Sheets-Sheet 4 F 1- F 5/ l I I FUEL 5A FUEL 5 l TANK TANK CONTROLLER i i E E 5 i v I i 52' a e;

i l I PLATE I I i I l i i l Br 1 0e 06 M M=L1U 1 l=kll INVENTOR HAN! SCHOLZ ATTORNEYS H. SCHOLZ Sept. 22, 1959 APPARATUS FOR THE COMBUSTION OF LIQUID FUELS 5 Sheets-Sheet 5 Filed Feb. 17, 1956 ATOMIZING AGENT INVENTOR HANS SMULZ BY W y ATTORNEYS tates APPARATUS FOR THE COMBUSTION OF LIQUID FUELS Hans Scholz, Dortmund, Germany, assignor to Dortmund- Hoerder Huttenunion Aktiengesellschaft, Dortmund, Germany Application February 17, 1956, Serial No. 566,307 Claims priority, application Germany May 9, 1955 17 Claims. (Cl. 158-76) This invention relates to new and useful improvements in the combustion of liquid fuels. The invention more particularly relates to an improved apparatus for atomizing and combusting liquid fuels and an improved burner construction.

Burners which are operated with liquid fuels such as fuel oil or the like are utilized in many industrial furnaces. Such burners must finely atomize the liquid fuel and intimately mix the atomized fuel with the oxidizing agent so as to obtain complete combustion. In order to obtain a complete and efiicient combustion it is necessary to completely vaporize the fuel. As is well known, the finer the atomization of the fuel, the more rapidly the vaporization will proceed. In order to obtain the finest possible atomization, super-heated steam has been used in place of cold-compressed air as the atomizing agent. With the use of such steam, however, various problems and disadvantages arise as, for example, in increased scaling of the metal when the burner is used in conjunction with an open-hearth furnace.

Burner constructions are known in connection with which the liquid fuel flows from a feed-pipe through suitable nozzles into a chamber in which the fuel is placed in a strong turbulent motion by repeated impingement against the chamber walls. The fuel which has been placed in this turbulent motion, however, emerges from the burner nozzle in the form of coarser droplets rather than in the form of a fine mist. The air or oxygen for supporting combustion is mixed with the fuel with further turbulence. With such burner constructions, however, a relatively long combustion path occurs and in order to avoid flare-back a correspondingly large combustion chamber must be provided. In conventional burner construction operating on this principle, for example, a feed pipe would be provided which would lead into a mixing chamber of somewhat larger cross-section through smaller nozzles. The burner nozzle would be provided at the forward end of the mixing chamber. The fuel and atomizing agent would be passed through the feed pipe nozzles into the mixing chamber where the same would be placed into strong tutrbulent motion by repeated impingement on the chamber walls. The fuel would then emerge from the nozzle in the form of coarser droplets and burn upon becoming mixed with the combustion air.

One object of this invention is the provision of apparatus for the atomization and combustion of liquid fuels in a manner which avoids the above-mentioned disadvantages, which allows the atomization to be effective with the use of relatively low pressures and which allows a relatively short combustion time and an extremely efficient combustion. This and still further objects will become apparent from the following description read in conjunction with the drawings in which:

Fig. 1 is a longitudinal section through an embodiment of a burner in accordance with the invention,

Fig. 2 is a cross-section of the burner shown in Fig. 1,

Fig. 3 is a further cross-section of the burner shown in Fig. 1,

Fig. 4 is a longitudinal section of a further embodiment of a burner in accordance with the invention,

Fig. 5 is a longitudinal section showing in further detail the forward portion of the burner shown in Fig. 4,

Fig. 6 is a longitudinal section showing a still further embodiment of a burner construction in accordance with the invention,

Fig. 7 is a longitudinal section of the flow guide member of the burner of Fig. 6,

Fig. 8 is a cross-section of the flow guide member shown in Fig. 7,

Fig. 9 is a further cross-section of the flow guide member shown in Fig. 7,

Fig. 10 diagrammatically shows an entire feed arrangement for a burner in accordance with the invention with manual feed control,

Fig. 11 diagrammatically shows an entire feed arrangement for a burner in accordance with the invention with an automatic regulation control,

Fig. 12 is a partial longitudinal section of a burner diagrammatically represented in Figs. 10 and 11,

Fig. 13 shows a cross-section through the burner shown in Fig. 12, and

Fig. 14 shows a further cross-section of the burner shown in Fig. 12.

In accordance with the invention, as contrasted to the turbulent flow conditions of the prior art, the atomizing of the liquid fuels and the mixing thereof with the oxidizing agent such as air, oxygen or oxygen enriched air, are efiected under conditions of quiescent flow.

The term quiescent flow as used herein is intended to designate a flow condition in which each individual particle retains its direction of movement and does not substantially change its relative position with respect to adjacent individual particles. The direction of motion in this connection need not necessarily be linear and the same may be curved. Thus, within the scope of the invention, the conditions of flow of an eddy may be termed quiescent provided that in the movement of the individual particles there does not take place any change which would lead to marked relative motion between the individual particles or rebounding of the individual particles. Such a relative motion between the individual particles or rebounding of the particles within the Scope of the invention may be termed as a turbulent fiow as opposed to the quiescent flow.

In accordance with the invention, the liquid fuel is first broken up into a large number of individual droplets by pressure atomization which may be effected in the conventional manner even under turbulent flow conditions. This initial atomization is termed a pre-atomization in accordance with the invention and the preatomized liquid fuel is moved forward linearly and preferably with a rotational or spiral motion in quiescent flow with an atomization agent and preferably a combustionsupporting gas. As a result of this a homogenization occurs which results in a tearing-apart of the individual droplets so as to form a fine mist of particles which are thus capable of suspension. With the quiescent flow, the mist cannot recombine into individual particles as would occur if turbulent flow conditions were prevalent.

With the mist formation which can remain in suspension, it is possible to obtain the ideal maximum combustion efficiency of a liquid fuel.

The invention will be described in further detail with reference to the embodiments shown in the accompanying drawings. In the embodiment shown in Figs. 1, 2, and 3, the rear portion of the burner is constructed as a pre-atomizer having an annular pre-atomizing space 7. A liquid fuel such as fuel oil is passed tangentially into this annular space 7 through the nozzle 6 and the atomizing gas is passed into the annular space 7 through the nozzle 6'. This arrangement may best be seen from Fig. -Z. Due to the tangential entry of the liquid fuel and the gas through the nozzles 6 and 6' respectively, a rapid rotation is caused in the annular space 7 due to which the liquid fuel is torn apart into large droplets by the gas. The flow path at this point is too short for a more extensive tearing apart of the individual droplets into a large number of mist particles. Furthermore, even if such a tearing apart of the individual droplets would occur, the same would re-combine again as a result of the centrifugal impingement against the walls of the annular chamber. In spite of this, the annular chamber is preferably so developed that all sharp edges and dead corners which might lead to a condition of turbulence are avoided. a

In front of the annular pre-atomization chamber 7, an elongated atomization chamber 3 is provided which is in the form of an elongated tube or pipe. Leading into the atomization chamber 3 is a conically narrowing chamber which is connected to the annular pre-atomization chamber 7 through tangentially arranged nozzles 8 Which extend through a flow guide member 9. The flow guide member 9 has a conically shaped tip which extends into the chamber 10 so that the chamber 10 actually has the form of a smoothly conically converging annular chamb'er.

. As the pre-atomized mixture passes through the nozzle 8, the same is imparted a further rotary motion in the chamber 10 and as the mixture passes through the chamber 10 into the atomization pipe 3 the same has an opportuiiity to develop its rotary motion to its fullest extent. Due to the flow guide member 9, the chamber 10 is in "the form of a smoothly converging annular passage so that no dead fiow areas may occur which could cause turbulence. The conical shape of the flow guide member 9 corresponds to the conical shape of the opposing wall portion of the housing which forms the chamber 10. As the mixture passes through the elongated atomization pipe 3, the same follows a helical rotating path with Quiescent flow. The helical rotating path is caused by the rotary motion previously imparted to the mixture. The atomization pipe is sufiiciently long so that with this helically rotating advance of the mixture an aerodynamic tearing-apart of the same may occur into fine mist partiples and the same will not recombine due to the quiescent flow characteristics. A burner mouth or tip is provided atjthe forward end of the atomization pipe 3.

Surrounding the atomization pipe 3 is a further pipe 'of greater diameter which forms the annular space 12 into which oxygen may be passed. The oxygen flows in a forward direction in the same manner as the atomized 'mixture towards the burner tip or mouth. The burner tip or mouth is formed by the flow guide member 13 which is conically tapered at each end in the annular s ace 17. and which is provided with a central bore leading from the atomization pipe 3. The forward portion of the central bore of the guide member 13 conically widens and a doubly conically shaped flow guide member 14 is inserted in this widened portion so that a conically diverging annular path is formed as an exit from the atomization pipe 3. Due to the shape of the forward ends of the flow guide 13 and 14, the chamber 12 has a forward exit in the form of a converging annular passage 19 into which the diverging annular passage 16 leads. The oil mist emerges from the passage 16 and mixes with the oxygen emerging from the converging annular pas- "sage 19. A double water jacket 17 and 18 surrounds the forward portion of the entire burner arrangement so that the portion of the burner arrangement which is inserted in the interior of the furnace may be water-cooled. V A very rapid, complete and efficient combustion of the fuel may be effected with the burner arrangement as shown using relatively low pressures.

In order to maintain the high degree of atomization in the atomizing pipe 3 and to prevent the fine mist from partially combining when the same contacts the inner wall of the pipe, it has been found preferable to heat this inner wall 11 to atemperature which is above that of the oil mist so that there is present a perceptible temperature gradient. As a result of this, a repelling action against the impinging mist occurs. A temperature gradient of at least 20 and preferably 50, between the wall 11 and the flowing oil mist has been found suflici'ent for this repelling action. This temperature gradient may be established by heating the wall 11 in any known or desired manner and preferably by heating the oxygen passing through the chamber 12.

Figs. 4 and 5 show a preferred embodiment of the invention in which this heating of the flowing oxygen is effected to establish the temperature gradient between the wall 11 and the oil mist. As shown, the chamber 12 is formed as a double annular chamber by the concentrically positioned pipe sections 22 and 23. The oxygen is passed in at the forward end through the connection 21, shows through the outer annular space and then through the inner annular space 12 toward the burner 10. As the oxygen flows along the outer annular space, the same is heated by the heating jacket 25 provided with the electric resistance heating elements 24. In addition, to aid in the heat transfer from the heated oxygen to the wall 11 of the atomization pipe 3, heating ribs or fins 31 are welded to the outer surface of this pipe. In order that the mixing nozzle at the burner tip does not have any impact surface for interrupting the quiescent flow and causing recombining of the oil mist into coarser particles, it is developed by means of the flow guide 'member 14 in the form of a double cone as mentioned above. As a result of this flow guide member, the rotary motion and direction of rotation of the oil mist is retained since the inwardly directed conical part of the flow guide member 14 forms the conically diverging central bore of the flow guide member 13 as a conically diverging annular passage. The outwardly directed conical portion of flow guide member 14 also aids in preventing recombining of the oil mist since the same fills up a region which would otherwise be a dead flow region and could effect a very disturbing influence on the mixing of the oil mist with the oxygen flowing out of the annular passage 16. With this conical shape, however, the combining flow paths merge together in a very favorable manner. Additionally, if the flow guide member 14 is heated up by the combustion to a temperature at which a flow repelling occurs in the same manner as in connection with the heating of the pipe wall '11, the outwardly directed conical shape, in conjunction with this repelling action prevents a recombining of the oil mist.

The heating ribs or fins 31 are preferably formed in the manner of a helical screw or worm having the same direction of rotation as the direction of rotation of the oil mist in the atomization pipe 3. With this shape, the oxygen, as the same flows through the chamber '12 toward the nozzle 10 is imparted a rotary helical motion corresponding to the motion of the oil mist flowing through the atomization pipe 3. With this rotating'motion, the oxygen, as may best be seen from Fig. 5, as the same emerges through the annular passage '19, will have a motion corresponding to the motion of the oil mist. In this way, the occurrence of turbulence which would cause arecombining of the oil mist is avoided and the homogenizin'g effect of the two media flowing together with different Reynolds number brings about an approximately ideal mixture condition. In this connection, the :state of flow remains preferably quiescent despite the rotary motion of the two media. The flame produced receivesits axial components of advance away from the burner tip by the angle of incidence of the flanks and the aperture cross-section of the annular nozzles through which the oxygen emerges. The part of the heating the oxygen is occurat times. vance with a preferred embodiment of the invention, may

burner extending into the furnace as, for example, the hearth, is protected by a water-cooled jacket in the same manner as described in connection with the embodiment of Fig. 1. In Fig. 5, the direction of advance of the oxygen stream is designated by the arrowed path labelled 28 and the direction of advance of the atomized oil mist is designated by the arrowed path designated 27. As may be seen from Fig. 5, the flow guide body 14 is maintained in place by means of the support ribs 15 which may, for example, be inclined at the angle of the helical path of the oil mist.

While in the embodiments shown, the pre-atomization takes place in the rear portion of the burner, it is also possible for the pre-atomization and the fine atomization to take place in the vicinity of the burner tip or mouth. Such an embodiment is shown in Figs. 6, 7, 8 and 9. In this embodiment, the oil 'is passed through the central pipe 3 to the flow guide membe 9 and sprays through the nozzles 34 as may best be seen from Fig. 8 at right angles to the burner axis against the opposite pipe wall. Compressed air is passed into the annular space sur rounding the pipe 3 and is imparteda helical rotational motion by means of the ribs 32 which are in the form of a helical worm. The ribs 32 may be welded directly to the pipe 3. The contacting of the oil sprayed through the nozzles 34 with the helically moving compressed air stream causes the oil stream to be broken up into particles so that the spray or rough atomization is effected. The

pre-atomized fuel then passes through the nozzles 35, the

construction of which can best be seen from Fig. 9. These nozzles are twisted or helical nozzles shaped in the manner of a guide stator, of .a turbine. vThe pre-atomized fuel is imparted the necessary twist by these nozzles and passes through the conically narrowing portion 10 into the forward portion of the pipe 3 in which the fine atomization takes place. A flow guide member 9' extends into the conically narrowing portion 10 and has a. conical shape converging in the same direction as the portion 10. With the guide body 9', a passage from the nozzles 35 to the forward portion of the pipe 3 is formed which has an annular conically converging shape. The guide body 9 prevents the formation of dead flow areas which might cause turbulence. As the pre-atomized mixture passes through the passage 10 into the forward portion of the pipe 3 with the linearly advancing helical quiescent flow the fine atomization occurs with the oil being divided into a. fine mist in the manner described in the previous embodiment. In all other respects the construction and operation of the burner corresponds to the embodiment as shown in Fig. 4. The forward portion which extends into the furnace or hearth and which has the water-cooled jacket is designated 1 whereas the latter part which is provided with the electric resistance heating element for designated II. In place of the electric resistance heating any other heating means may be provided as, for example, a'steam jacket for superheated steam or the like. The parts I and II are connected together by means of a compensator 36.

With the burner construction it is possible to operate at relatively low pressures. At these lower pressures, however, the tendency toward fiickering ofthe flame may This disadvantage, however, in accordbe avoided by maintaining the fuel inlet pressure into the burner and particularly at the entrance into the atomization chamber equal to 'the pressure of the atomizing agent. It has furthermore been found desirable to adjust the velocity of emergence of the atomized oil from the burner at an optimum value in proportion to the .outlet velocity of the oxidizing agent from the mouth of the burner.

n The regulation of the oilpressureandthe pressure of the atomizing agent so that the same are substantially equal to each other may be effected manually or auto natically.

In the embodiment as shown diagrammatically in Fig. 10 the adjustment is effected manually. As shown, a storage tank 51 is provided for the fuel oil. The fuel is introduced into this tank through the feed line 52 after opening of the vent vale 5%. When the burner Br is placed in operation, compressed air which is used as the atomizing agent is conducted from a suitable source such as a compressor to the reduction valve 54 into the tank 51 and exerts a feed pressure on the oil contained therein. In the drawing the oil lines are shown as solid lines, the compressed air lines as dash lines and the control lines as dotted lines. The quantity of fuel to be burned in the burner Br is adjusted by the orifice plate 56, the U-tube manometer 58, and valve 57. The inlet pressure into the pie-atomizing chamber is indicated on the pressure gauge 02. The atomizing agent, i.e., the compressed air, enters the mixing chamber of the burner Br through the reduction valve 55 and the line 48. The inlet pressure of the compressed air into the pre-atomizing chamber is indicated on the pressure gauge Z. The pressures of the oil and of the compressed air are regulated by adjusting the reduction valves 54 and 55 so that the indications on the pressure gauges Oe and Z coincide with each other. The pressure prevailing in the pre-atomizing chamber itself is indicated from the pressure gauge M.

It is also possible to provide for an automatic adjustment of the reduction valves 54 and 55. An embodiment of such an automatic adjustment is shown diagrammati cally in Fig. 11. The construction corresponds exactly to that shown in Fig. 10 except that the manual pressure reduction valves 54 and 55 are replaced by the automatic valves 54 and 55 which are controlled by an automatic control regulator 58 which is connected to the lines 48 and 49 respectively. The automatic regulator 58' is of conventional construction and adjusts the valves 54' and 55' so that the pressures in the lines 48 and 49 remain equal.

A burner construction, in accordance with the invention which is particularly adaptable for use in connection with the set-ups diagrammatically shown in Figs. 10 and 11 is illustrated in Figs. 12, 13 and 14. In this burner con struction, the fuel oil is passed into the pre-atomizing chamber 7 through the line 49 while the atomizing compressed air enters this chamber through the line 48. Both lines have connections for the pressure gauges Oe and Z respectively, as may be seen from Fig. 14. The nozzles 6 and 6' are interchangeable with nozzles of a different cross-section and the particular cross-section used depends upon the quantity ratio of oil and atomizing medium, the viscosity of the liquid fuel, and the specific gravity of the atomizing medium. The pre-atomization takes place as a result of the rotating movement of the compressed air and oil in the chamber 7 in the same manner as the previously described burner embodiments. The pressure in the prc-atomizing chamber 7 is. measured via a bore 43, annular space 44 and connection 45, by the pressure gauge M. From the pro-atomizing chamber 7 the mixture passes through the nozzle slots 8 and 8' into the central atomizing pipe 3 of the burner Br in the same manner as in the previously described constructions.

The construction and operation of the embodiment is similar to the previously described constructions except that the flow guide member 9 is formed with a piston 41 which is movable by means of the spindle 42 and the manual setting lever 46. By means of this piston, the cross-section of the nozzle slots 8 and 8 may be increased or decreased in order to change the pressure in the preatomizing chamber 7 as desired. As has been mentioned, this pressure is indicated on the gauge M.

The part of the inlet pressures in the mixing chamber 7 which can be read from the pressure gauges 0e and Z .which is intended for the pre-atomization is preferably section of the chamber 7 should be imparted a suitable adjustment of the burner 7 aerodynamic shape, such as the pear shape shown. The pressure regulation effected by the shifting of the piston 41 with the conical part 9, may then be effected with the losses in the pre-atomization reduced to a minimum.

It has been found preferable to maintain the following conditions in operation with the oil pressure in front of the nozzle 6 being designated e, the pressure of the atomization agent in front of the nozzle 6 designated Z and the pressure in the mixing chamber 7 designated M;

Condition 1: (0e)/ (Z)=1, regardless of the fuel rate Oe and Z should be smaller than 4 atmospheres gauge, preferably about 2 atmospheres gauge.

Condition 2: The difference between the average inlet pressure of the fuel and the atomizing gas should be maintained as small as possible. This difference may be designated as from the burner mouth, with the ratio of V zV greater than about 3.

The uniform, flicker-free operation of the burner is assured after a simple determination by experiment of the optimum mixture ratio K of compressed air (or theatomizing agent) and fuel in accordance with the formula In this formula al is the internal diameter of the nozzle 6' for the entrance of the atomizing agent into the chamber 7 and 41 is the internal diameter of the nozzle 6 for the entrance of the fuel into the chamber 7. In this connection -0.1 and the values for K have been found by experience to be between 100 and 200 when compressed air is selected as atomizing agent. It is therefore preferable to have the outlet velocity of the oxidizing agent (combustion air or air enriched 100% with oxygen) more than twice the outlet velocity of the fuel mist from the burner mouth.

Since the operating conditions change, depending on the purpose of use (nature and shape of the furnace), the can be effected in accordance with the best possible operating results obtainable, and, what is particularly important, independently of the average fuel rate or from that which exists specifically at the time.

The apparatus of the invention can be used to particular advantage in the production of steel in open hearth furnaces.

I claim:

1. A liquid fuel burner comprising means defining a preatomizing chamber, means forming an elongated tubular atomizing chamber positioned coaxially in front of said pre-atomizing chamber and defining at its forward end a burner mount, means forming a conically converging annular passage connecting said atomizing and preatomizing chambers, means for passing a liquid fuel and an atomizing gas into said pre-atomizing chamber for atomization contact therebetween, a tubular member coaxially surrounding said atomizing chamber defining an annular passage between it and said atomizing chamber and terminating as a conically converging portion at the burner mouth, a flow guide member conically tapered at its opposite ends surrounding the forward end of said tubular atomizing chamber and positioned in said annular passage defining with the conically converging portion at the burner mouth a conically converging annular passage, a second flow guide member having a conically tapered rear and forward end positioned with its rear end extending into the forward outlet end of said atomizing chamber and defining therewith a conically diverging passage and with its forward end extending outwardly in the burner mouth, and means for passing an oxidizing gas through said annular passage toward said burner mouth.

2. Burner according to claim 1 including means for heating the wall of said atomizing chamber.

3. Burner according to claim 1 including means for imparting to the oxidizing gas being passed through said annular passage a rotational flow motion with the same rotational direction as said rotationally directed nozzles.

4. Burner according to claim 3 in which said last-mentioned means comprises a helical rib surrounding said atomizing chamber extending into said annular passage.

5. Burner according to claim 4 including means for heating oxidizing gas being passed through said annular passage.

6. Burner according to claim 5 in which said last-mentioned means comprises electrical heating means.

7. Burner according to claim 1 in which the forward portion of the burner has a cooling jacket surrounding it.

8. Burner according to claim 1 in which said pre-atomizing chamber is an annular chamber having a tangential liquid fuel inlet nozzle and a tangential atomizing gas inlet nozzle.

9. Burner according to claim 8 in which said conically converging annular passage connecting said atomizing and preatomizing chambers is formed by a conically shaped wall and a corresponding conically shaped flow guide member centrally positioned in spaced relationship to said wall.

10. Burner according to claim 9 in which said flow guide member has a rear cylindrically shaped portion and including means for axially moving said flow guide member so that said cylindrical portion moves across a portion of the cross-section of said rotationally directed nozzles.

11. Burner according to claim 10 including means for adjusting the pressure of fuel and atomizing gas being passed into said pre-atomizing chamber.

12. Burner according to claim 11 including means for automatically maintaining the pressure of fuel and atomizing gas being passed to said pre-atomizing chamber substantially equal.

13. Burner according to claim 1 including means for adjusting the pressure of fuel and atomizing gas being passed into said pre-atomizing chamber.

14. Burner according to claim 1 including means for automatically maintaining the pressure of fuel and atomizing gas being passed to said pre-atomizing chamber substantially equal.

15. Burner according to claim 1 in which said preatornizing chamber is an annular chamber and in which said means for passing fuel into said pre-atomizing chamber comprises a central fuel conduit terminating with radial nozzles extending substantially normally into said annular pre-atomizing chamber, and in which said means for passing atomizing gas into said chamber comprises an annular conduit surrounding said central fuel conduit, means for passing atomizing gas into said annular conduit and means for imparting to the atomizing gas being passed through said annular conduit a rotational flow direction.

16. Burner according to claim 15 in which said lastmentioned means comprises a helical flow guide rib surrounding said fuel conduit and extending into said annular conduit.

17. Burner according to claim 1, including a member having rotationally directed nozzles defined therethrough separating said annular passage from said pre-atomizing chamber.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Crowe June 5, 1951 Kermode Dec. 5, 1899 Schutte May 10, 1904 Kemp Apr. 17, 1906 Higgins Oct. 23, 1906 Lukenbach June 2, 1908 Rigg Aug. 2, 1910 Tucker Apr. 20, 1915 Start June 7, 1921 Hildebrandt Dec. 11, 1923 10 Lusk Oct. 28, 1930 Benjamin Feb. 23, 1932 Kinder May 14, 1940 Schultz Aug. 20, 1940 Crosiar Oct. 29, 1940 Hoifert Feb. 20, 1951 Schwietert Oct. 14, 1952 Benedek Aug. 2, 1955 Cress Jan. 24, 1956 FOREIGN PATENTS France Jan. 6, 1925 Switzerland Mar. 1, 1922 UNITED STATES PATENT OFFICE CETlFIfiATE @F CUR ECTION Patent Noa 2,905,234 September 22, 1959 Hans Scholz It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column '7, line 62, for "mount" read mouth a Signed and sealed this 22nd day of March 19609 (SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Ofiicer Commissioner of Patents

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