US1805066A - Gas burner or nozzle - Google Patents

Description

y "I931. P.'J. J. ANDRIEUX 3 9 GAS BURNER 0R NOZZLE 2 Sheets-Shae! Filed April 23, 1929 y' 1931. P. J. J. ANDRIEUX GAS BURNER OR NOZZLE Filed April 23, 1929 2 Sheets-Shea! 2 //V VE/V 70/? Pierre la/es J0 Ia/e/I lair/ear ATTORNEY Patented May 12, 1931 uma 1S PIERRE JULEs .rusrnvrnn ANDRIEUX, onmournnoune, re meeAs BURNER, on uozZLn Application filed April 23,1929, Serial No. 357,534, and in France May 2 1928.

- The present invention relates to gas burners or nozzles adapted for thecombustion of a mixture of hot or cold air or Oxygen, or like gas, and a combustible consisting of finely 1- powdered solid fuel, or of a liquid or gaseous fuel, and more particularly'to burners ofthe type comprising a central core.

One object of. thepresent invention is to provide a humor of the above mentioned on type which will afford a perfect combustion throughoutthe whole thickness of the'flame; another important object is to obtain a flame ofellipsoidal shape without high heated axial point and in which the region of the strongest combustion is at the exterior; a. further object resides in the provision of means whereby the diameter andthe length of the flame maybe-easily varied at will.

In the appended draw1ngs,-wl1ich are given solely by way of example r Fig. 1 is adiametrical and longitudinal sec- 7 tion of a burner according tothe invention. i Fig. 2 is an end view of the device shown inFig. 1 according to the line A .A.

. Fig. .3 isf'a cross section, perpendicular to the longitudinal axis of the burner, on the line BB of Fig. 1.

Fig. 4: is'a sectional furnace, :such as a cement view of end of a furnace, showing -10 the disposition of the burner and the shape of.

the flame obtalned wi-ththe burner in con formity to'theinvention. v Fig; 5 isa cross section on a largerscale on the line C-C ofFig. l, of the jet or fuel mixtureissuing from the burner.

Fig. 6 is a diagrammatic view showing the flame obtained with the knownburners having asimple jet. 1

o In the construction shown in Figs. 1,2 and 3, the whole amountv of the fuel is'supplied to the cylindrical conduit connecting the burner to a blower (not shown) whichwdelivers ahigh pressure blast. A joint with inclined surfaces 2 servesto adjust the direction of the nozzle. i

The said blower d livers to the conduit only a part of the air necessary for the combustion, which will be designated asprimary air, this air being also adapted to produce an energetic stirring and mixing of the fuel and to provide for a high speed when issuing from the burner or nozzle.

The said burner comprises a cylindrical part 3 in the region a 71 extending from the saidconduit supplied by the'blower. At the end of saidcylindrical part '3 isEa tapered sheet metal chamber which has a funnel shape at thepart b 0; and is cylindrical at the part c 03, then having an inverted funnel shape at 6 at thepart c c, this being followed by .a'cyfig lindricalpa-rt es of a few centimeters length. In the combined device 3,4, v5, 6., is disposed a I solid or hollow internal core which is' ta-pered at 7 at the part f g, and iscyl-indrical at 8 outwardlyof g, as far as the outlet h ofthe burner or nozzle. The said core is secured in position-by the cross members 9.

1 The said-device is completed acylinder 1O concentric with the cylinder B of the cen tral core. Into the said cylinder 10:, which .74) extends as far as-Z 'or to the outlet of the burner, is inserted the tapered part '6, allowing betweenthelatter and the base 10-01 the cylinder 19 a space 11 for theadmission of'an additional supply of "air (secondary air). E5 The cylinder :10 is preferably terminatedby a tapered part 12 whose-function will he fur .ther specified. s a. The operation-of the said blast nozzle is asfollows: 1 wThe mixture of. fuel and primary air is supplied to'thc cylinder .3, andpat f themass of gas forms a hollowcylinder whose wall is thick atthe part, Z2 10 v(ligand .becomes thinner at the part cl 2; corresponding to the converg- 35 ing part-'6 of the nozzle. During its flow 'in Z 0' d c the gas undergoes from]; to 0 a' change of direction, speed and form, thus producing a whirling motion which the mixture of fuel and primary air is well stirred.- j

' The progressive reductionof theffiow section in the part 03 6 results in a'continuous increase-ofth-e speed of said mixture,"and

"this attains its maximum at e "at' 'the outlet of the tapered'part' b, thus forming a hollow the flame 8 at a reduced thickness and without being separated from the said wall 8, due to the action of the flow of fluids upon Walls.

The secondary air required for the combustion of the said mixture of fuel and primary air is admitted at 11. The high speed of flow of the gas issuing from s will. cause the suction of the secondary air, this being furthered by the tapered end 12 of the cylinder 10. This air may be either hot or cold, and in particular it may be heated by contact with hot material which is being cooled in a cold part of the furnace, or in a separate cooler employed with the furnace.

The cylindrical chamber 8 ending in the tapered part7 (should a hollow core be used) can be supplied with hot or cold air through the pipe 13 by means of a blower or the like.

Due tothe aforesaid construction, the cylinder of gas discharged from the end of the burner will not be homogeneous,but is in fact heterogeneous and comprises three distinct regions, surrounding the longitudinal axis of the nozzle (Figs. 3 and 5).

A.The central region has the form of a cylinder'of air 14 if air is injected into 17, or otherwise a vacuum will be formed.

B. At the periphery of the said cylinder of air 14 is situated a thin cylindrical layer 15 consisting of fueland cold primary air.

C.A cylinder of secondary air is formed at 16, this being hot or cold; it is in line with the nozzle and forms the outer region of the gas stream discharged by the nozzle.

lVith the said nozzle, which enters for a relatively longdistance into the furnace 17, due to its great length, the combustion takes place as follows: The cylinder of air 16 becomes heated by radiationfrom the walls of the furnace, and'it expands when it enters the heated furnace chamber, the expansion being greater'as the jet proceeds farther from the nozzle, and this constitutes around'the cylinder 16 which is formed of a mixture of fuel and cold primary air an envelope of a very hot oxidizing gas which greatly furthers the combustion of themixt'ure of fuel and primary air as well as the outward spreading of perpendicularly to the axis of the burner."

After the air 16 hasbeen heated, the gas cylinder 15 consisting ofthe mixture of fuel and primary air is in turn heated at its outer part, and this becomes ignited at a certain distance from the nozzle, the combustionthen progressing through the mass, and spreading throughout the entire mass within a short time, the thickness of the layer of gas being small and its surface which'receives heat by radiation from the chamber being large.

The gases resulting from the combustion of the primary mixture expand with great force and seek to spread and to complete their Combustion. They encounter at the exterior an environment which is well adapted for this purpose, that is, the region of hot air 16.

In the interior, on the contrary, the central cylinder of air 14.- remains at a lower temperature until the gaseous mass is in complete combustion; since the temperature of this air is lower, it does not further the spreading of the flame to the interior, and on the other hand the expansion of this air when in contact with the flaming gas will tend to remove the gaseous mass charged with combustible substance, and hence the region of combustion, from the axis of the nozzle.

In practice, the apparatus affords a flame of ellipsoidal form and without a highly heated axial point, in which the region of the strongest combustion is at the exterior, as compared with the nozzle of the current type 18'having a simple jet in which the flame has the form shown in Fig. 6 comprising three regions, firstly a region 19 in the interior which is without'brightness and comprises the mixture of fuel and air which does not burn, since the action of the radiation from the exterior fails to heat this mixture suiticiently to allow it to burn; secondly, a region 20 in which the combustion progresses, by successive contact, from the exterior towards the axis of the flame, this being a region of incomplete combustion having reducing properties; thirdly, a region 21 situated at the point of the flame and on the axis, in which the gas attains its complete combustion in a highly heated environment.

It is obvious that in the gas burner, the. subject matter of the invention, the diameter of the flame in a plane perpendicular to the axis can be regulated, since the flame can be shortened while its diameter increases, this effect depending directly upon the mount of secondary air supplied at 11 and upon the temperature of this air.

This adjustment can be made chiefly by the use of the tapered part 12 Whose displacement varies the intake section 11, and the flame can thus be regulated to obtain a great thermic efficiency both by radiation upon the material and by direct contact between the flame and the material to be heated.

The invention is obviously applicable to all nozzles or gas burners.

The secondary air may-be heated by the use of any desired system for the recovery of hot gas and air, whether directly by the suction of the burner or nozzle, or indirectly.

Thesaid invention is chiefly applicable to the revolving'furnaces employed in metallurgy, or in the cement or the chemical industries, or the like. In such cylindrical or cylindro-conical furnaces, the flame from the said burner will proceed along the walls of the furnace and it thus makescontact with the material to be heated and with the walls of the furnace.

In such. furnaces, when a region of maxizle or burner, around the saidmateri'al in course of cooling.

The said burner permits, and chiefly in the revolving cement furnaces in which finely powdered coal is burned, eliminating all air in excess of the quantity actually required for the combustion. In such furnaces, which comprise a cooling device (not shown) which is supplied through one or more conduits 21 with the material clrculating in the furnace in the direction of the arrow .7, a considerable amount of air is admitted into the furnace by the said cooling device and the conduit or conduits 21, and this air, after recovering the heat given off by the material while cooling, enters the front part of the furnace in which it becomes gradually heated by its contact with the material proceeding from the heating region towards the said cooling device. This heated air attainsthe region oftheburner, and then reaches the flame. With the known burners, it is observed that the major part of this air passes around the flame between its outer walland the lining of the furnace, since the flame produced by an ordinary burner has a small diameter and a great length on the axis of the burner and the furnace, and it is thus at some distance from the Wall of tlie furnace.

The burner according to the invention offers the following advantages. On the one hand it distributes by automatic suction in the burner around the mixture of fuel and the major part of the air heated by recovery and facilitates the complete combustion of the elements, andon-the other I hand it produces a flame of large diameter struction,

which occupies nearly the whole of the section of the furnace as far as itswall.

The air used in the recovery of heat, when proceeding from the head of the furnace and attaining the region of combustion, encounters the flame which thus constitutes an obsince this flame extends to the wall of the furnace, and hence the whole of the hot air recovered is utilized for the complete combustion- In practice, the supply of priresponds to a reduced quantity of the'powmaryair is regulated accordin to needs in order to obtain the complete com ustion with out excess of air, this regulation depending upon the analyses of the gas issuing from the furnace. The diameter of the cylinder 10 is made such that the optimum quantity of hot air will be supplied to the burner, and this affords a complete combustion with a minimum amount of air, thus reducing the heat losses due to the discharge of the gases of combustion. This reduced amount of air corrounding a central core of the'same length asbefore and parallel to the longitudinal; axis, and each unit tube comprises an ejector for secondary, air. The ejector herein represented may be replaced by any other ejector serving thesame purpose, Without departing from the principle of theiinvention.

.' I-Iaving now described my invention what I claim as new and desire to secure by Letters Patent-is: I 1 1. Ina process for burninggaseous, liquid or powder-ed solid fuel,thefstepsconsistlng I in blending fuel with a fluidsupporting com bustion,'in forming saidmixture into an annular and substantially cylindrical layer having thin walls with respect to its diameter, imparting to said mixture a high velocity while thoroughly guiding same, in surrounding said layer with an external sheath of fluid supporting combustion formed into a'substanti-ally' hollow cylinder, the inner diameter of which is substantially equal to the'outer diameter of said layer and so guided that' it "will comeftangentially into contact with said layer, and in guiding 'both said annular layer and sheath in contact Withone another, While substantially preventing them from mixing together, whereby they will be able" to flow through a surounding heated medium while substantially keeping their cylindrical shape and without burning till the outer sheath will be sufliciently heated by the surounding medium.

2 In a process as claimed in claim 1, regulatlng atwill the quantity of fluid supporting combustion contained in the outer sheath,

whereby varying at will the stroke which both the sheath and layer are capable of performing in direct contact withthe surrounding heated medium before the combustion takes place.

. 3. A burner comprising in combination an elongatedtubular body connected at one end with means for supplyingthereinto a flow of a mixture of, fueland fluid supporting combustion, a core axially disposed withinsaid body and defining therewith an annular space I through Which the whole amount of said mixture 1s caused to flow, said core extending into a substantially straight and cylindrical sur-.-;.

face projecting greatly ahead of the outlet of said body, the outerdiameter of said cylindrical extension being smaller than the inner diameter of the body outlet, a substantially cylindrical tube ,coaxially disposed with said core and surounding at a distance the projecting part of said core, theinner diameter of said tube being greater than the inner diameter of the body outlet and means for supplying a fluid supporting combustion into said space between the core and the surrounding tube, so as to form a substantially annular sheath coming tangentially into contact with the annular cylindrical layer of mixture issuing from said tubular-body, the end of the straight and annular channel defined by the projecting part of the core and the. tube surrounding it forming the outlet of the burner.

4.- A burner as claimed in claim 3, comprising means whereby the amount of fluid supporting combustion supplied into said straight and annular channel may be varied at will.

5. A burner as claimed in claim 3, wherein said elongated tubular body comprises first a cylindrical part-adapted to be connected at one end with said mixture supplying means and extending at the opposite end into a tapered part of increasing cross-section itself I prolonged by a second cylindrical part merging into a second tapered part of decreasing cross-section, the latter ending into a third cylindrical portion of small length, and

wherein the core has a tapered closed end in register with said lirsttapered part of the tubular body, the arrangement being such that the flow section through the annular s ace in this region will be greater than the ow sections through said supplying means and adjacent the outlet of said tubular body. In testimony whereof I have signed my name to this specification. t v

PIERRE JllLliS JUSTlNlEN ANDRIEUX.

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