US2411181A - Combustion turbine burner - Google Patents

Description

Nov. 19,' 1946. H. A. ALToRFER 2,411,131

COIBUSTION TURBINE BURNER med April 1o. 194:5A

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CGMBUSTION TURBLNE BURNER l Hans A. dltorfer, Wauwatosa, Wis., assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application April l0, 1943, Serial No. 482,561

i Claims. y

This invention relates generally to the combustion oi iiud fuel and is directed toward and contemplates the construction of a fluid fuel burning apparatussuitable for use in combustion gas turbine and other high temperature fluid systems.

The primary object of this invention is to minimize the erratic operation o! combustion apparatus heretofore experienced and considered as being attributable, at least in part, to variations in the rate of fuel ow caused by a relative expansion or contraction of the nozzle and body portions of the burner, and/or to a, non-uniform Y 'atomization of the fuel, and/or to an incomplete mixing oi atomized fuel and combustion supporting air at a point immediately adjacent the burner nozzle.

More particularly, the present invention is directed toward and has as an object the provision of a combustion apparatus including a uid fuel burner and air directing parts operatively combined to eect an increase in the rapidity and extent to which primary air is mixed with atomized fuel immediately adjacent'the burner nozzle.

The hereinabove mentioned combining of burner and air directing `parts to effect an increase in the rapidity and extent to which primary air is inbred with atomized fuel immediately adjacent the burner nozzle affords a material advantage irrespective of the particular burner construction employed. However, best results are obtained by employing a burner embodying parts constructed and combined to minimize variations in the rate of fuel flow caused by a relative expansion or contraction of the nozzle ,and body portions of the burner, and/or to a. non-uniform atomization oi the fuel. And although such a burner is herein shown and described as comprising an element oi the combination deiined by the appended claims, the burner is oi 4general application andl embodies features of construction which have been made the subject oi! a. divisional application' Serial No. 649,721, :bled February, 23. 1946, to

which reference may be had for a .better under-- standing of the construction and coaction oi various parts thereof.

Combustion apparatus constructed in accordance with this invention may also embody parts detailed description, reference being had to the accornpeulyingl drawingV illustrating an embodiment of the invention and in which:

Fig. l is a partial longitudinal section through a combustion chamber embodying a burner and air directing parts combined in accordance with the present invention; and

Fig. 2 is an enlarged longitudinal section through the burner proper.

Referring to the drawing, it is seen that apparatos embodying the invention may include a ycylindrical combustion chamber forming shell l having kan air admission connection 2, a coaxial mixing chamber 3 defined by a tube i and axially spaced inwardly extending annular inner and outer Wall portions 6 and 1, respectively, forming therebetween an annular air passage B; guide venes 9 disposed between and connecting the outer portions of the walls 6 and l, and a burner H coaxially disposed Within said mixing chamber with its nozzle portion extending through and terminating a short distance beyond the coaxial opening formed by the inner peripheral edge of inner wall 6. The tube 4 is coaxially supported within combustion chamber l by means of radially extending coacting lugs or brackets l2 and I3 and boltsit, only one set of which is shown in the interest of simplicity, and wall E is spaced from and secured to the rear Wall i6 of combustion chamber i by means of brackets I'! and tap bolts i8; the burner being also removably mounted on rear wall IG by'V means of a plurality of tap bolts i9. The annular outer wall 1 addition to being connected to inner wall 6 by means of guide varies il is provided adjacent its outer periphery with a,

y coaxial collar br flange 2i telescopically engagm ing the adjacent end of mixing tube t for support thereon.

Annular Wall l extends radially inward for a short distance and then forward in coaxial parallel relation to the tube l, whereas wall t extends inwardly and forwardly toward the burner with its inner peripheral edge terminating short of and surrounding the nozzle end oi the constructed and combined in a manner considered' ci special importance with respect to compactness, durability and reduced manufacturing cost,

and accordingly the invention consists ci the verious details ci construction, combinations oi elements and arrangements of parts as is more fullyset forth in Vthe appended claims and in the burner in passage forming relation therewith. The interior of combustion chamber l is provided with an inwardly extending annular air directing Bange 22 positioned to divert some of the air entering through the connection Z into the passage 8 and into the passage 23 formed between annular inner wall o and the rear wall 6 of combustion chamber i from which the air flows along'the burner and through the opening 2t formed between the inner peripheral edge. oi wall' e and the nozzle portion oi burner it; the remainder the .inner peripheral extending coaxially therethrough Vsage :48 forming `continuations diverted by the Iiange 22 into and forwardly throughthe coaxial annular space 26 provided between shell I and mixing tube 4. In this connection, it should be noted (s ee Fig. 1) that the inner annular air diverting and directing wall 6 is shaped and arranged to form with the nozzle portion of the burner an inner annular air passage of decreasing cross sectional area in the direction of air ow therethrough to thereby sur- .tions to direct the air entering passage 8 forwardly in an annular stream surrounding the nozzle end of the burner. K

Referring to Fig. 2, it is .seen that burner Il embodies unitedbody and nozzle portions 21 and 28, respectively, surrounded by a tubular radiant heat reflecting shield 29 which may be chromium plated or otherwise treated to provide a .suitable reflecting surface and which is radially spaced from and secured to the means of spacing blocks portions 21 and 28 by 3| welded to body por- 'tion 21 and screws 32 and by having circumfer- 33 of its nozzle end bent entially spaced portions inward to engage the orice end of the nozzle portion. The remaining coaxially extending nozzle end portions 34 of shield 29 support an annular member 36 in surrounding passage forming relation tothe orifice end oi nozzle portion 28 and in axially spaced relation to the inner peripheral edge' of annular wall 6; member 36 having a diameter approximately equal to the diameter of the inner peripheral edge of wall 6 and being secured to the shield portions 34 in any suitable manner such as by welding. Member 36 is positioned and shaped flowing through the opening 24 provided between edge of wall 6 and shield 29 and the inner portion of the forwardly directed annular stream issuing from passage 8 inwardly against vthe fuel spray lemitted from the nozzle 'orifice at a p'oint immediately adjacent thereto.

Body portion 21 comprises a mounting block 31 having a bore 38 extending coaxially therethrough which 4has enlarged or counterbored outer and inner ends 39 and`4l, respectively, and an'enlarged intermediate portion 42, a tubular member 43 which is coaxially seated in counterbore 4| and forms a continuation of bore38 and which is welded or otherwise permanently secured to the block 31, and a second tubular member 44 rhavingr a peripheral flange 46 intermediate its ends abutting and welded to the inner end of tubu- .lar member 43 withits outer end portion telesCoped therein, having its inner end portion externally threaded, and having a series of bores 41 about the central lpassage 48 therein; the bores 41 and pasof the central passage 4'in tubular member 43. Block 31 also has '.formed therein. a transverse. bore 49 which ter- Vminates .1in-the v,enlarged portion 4.2 of bore 38 andAhas its outer end threaded and connected with a fuel return pipe a bore 52 extending axially outward from counterbore 4| antiterths feature forms ,of the` air entering through the connection 2 being minating adjacent the enlarged portion 42 of bore 38, and a transverse bore 53 terminating in the uter end of -bore 52 and having its outer end threaded and' connected with a fuel supply pipe 54.

Nozzle portion 28 includes a rst tubular member 56 having axially spaced outwardly extending projections 51 and 58 and having an inner reduced end portion provided with axially spaced series of ducts 59 and 6| extending transversely therethrough. And a second tubular member 65 surrounds member 56 and is in general spaced therefrom through engagement with the projections 51 and 58. The space between members 56 and 65 provides a passage 66 in continuous communication with coaxial bores 41 in body member 44. Member 65 has an externally threaded inner end and has its outer end internally threaded and secured to the externally lthreaded inner end portion of body member 44. An orice member 61 abuts the linner end of member 56 and is held clamped thereagainst by a tubular member '68 having an internallythreaded outer end portion secured to the externally threaded inner end portion of member 65. And it should be obvious that the purpose of member 68 is to secure orice member 61 and member 56 in coaxial abutting relation with the outer end of member 56 engaging the inner end of body member 44, as shown. A set screw 69 locks member 68 in'its clamping position just specied. A tubular valve element 1| is disposed within nozzle member 56 and has an externally threaded intermediate portion 12 engaged with an internally threaded intermediate portion of member 56 to thereby render elementl 1| rotatably axially movable therein. Element 1| has a coaxial bore 13 extending from its outer end, which projects intol the central passage 48 in body member 44, to a point adjacent its inner or orice end, and has a plurality of transverse bores 14 extending outwardly therethrough from the inner end portion of bore 13.

kOrifice member 61 The adjacent cylindrical portion of element 1| also closing the series of ducts 6| in the nozzle' end oi tubular member 56. 'I'he inner ends of the transverse ducts 5,9 in tubular member 56 terminate in a coaxial enlargement 18 of the central passage 64 therein and the outer ends of the bores 14 in valve element 1| also terminate in said enlargement to thereby maintain the coaxial bore 13 in valve element 1| in continuous communication with the space or passage 66 irrespective of whether said valve element is in its closed or fully open position.' The outer end of valve element 1|, thatis, the portion extending within the central passage 48 in body member 44, is provided with a radially extending coaxial key 19. and the actuation of said element is accomplished by means of a coaxial rod 8| which extends into bore 38 in block 31 and terminates within the enlarged portion 42 thereof and a tube 82 which is secured to the inner end of rod 8| for angular movement therewith and extendsI coaxially through the inner portion of vbore, 38, the counterbore 4|, the tube member 43 and into the central passage 48 in tube member 4,4 rwith its inner end telescoping the outer end of valve element 1|; the key 19 on said valve element being disposed within a coaxial 4slot 83 formed on the inner surface of said tube4 is provided with a valve seat "16 adaptedto be engaged by the orifice end of valve element 1| to close the orifice 11 therein..

handle 84 for .rotating same andthe counterbored portion 39 of bore 38 is filled with packing 86 which is held in place by a coaxial jam member to--which the primary air mixes with A:the atomized fuel issuing from the nozzle orifice and thereby effects complete combustion of the resulting 8l secured to the outer face of block member 3l by means' of tap bolts 88. 'Ihe outer end of tube 82 is provided with ducts 89 extending transversely therethrough and placing the interior of said tube in communication with the enlarged portion 42 which in turn communicates with the fuel return pipe 5l through the bore 49; the pipe 5| being preferably provided with a suitable valve 9| as shown in Fig. 1.

With the burner parts positioned asshown in Fig. 2 and the valve 9i in the return pipe opened, fuel under pressure from a suitable source (not shown) will iiow from supply pipe lill into bore 53, through bore 52 into the annular passage 93 formed between tube 82 and the surrounding tubular body member 43, through the coaxial bores 4l in body member 4H into the passage 6 formed between nozzle elements 56 and 65, through ducts 59 in element '56, through ducts ld in valveelement 1l into the coaxial bore 13 therein, through tube 82 and ducts 89 therein into the surrounding chamber formed by enlargement [i2 in block member 3l, and then through bore de into return pipe 5i. This arrangement permits fuel oil to be circulated through the burner after operation ceases in order to keep the burner cool; the circulation of oil therethrough being preferably controlled by a valve Si in return pipe di.

When it is desired to operate the burner, the handle BA1 is turned in a direction to withdraw valve element ll from its seat 'it on orice member 5l. thereby opening said orice and, depending upon the extent of the withdrawal, wholly or partially opening the series of ducts 6i in the orifice end of valve carrying element t6; the oriflce end of valve` element li forming with the opposed surface of orifice member tl acoaxlal fuel receiving chamber of variable axial length determined by the extent to which element ii is withdrawn from` its said seat. It is unnecessary at any time to supply an excess of fuel to the burner nozzle even for cooling purposes since the fuel for combustion flows through an outer surrounding passage, thereby effectively cooling the burner during normal operation; it being understood that during normal operation the valve 9i in return pipe bl is kept fully closed and that said valve is opened when combustion ceases in order to continue the cooling action for a time .interval sufcient to prevent carbonization of fuel in the nozzle portion of the burner. However, if additional cooling should be desired when operating under conditions effecting extremely high temperatures, the valve 9i may -be opened to permit some of the fuel to return through the inner passage as previously described.

The degree of atomization effected by passing a whirling mass of fuel through a coaxial orifice varies materially with changes in the whirling energy of the mass which in turn varies with changes 'in the velocity with which the fuel enters the whirling or receiving chamber. And in this connection, it has been determined that the use of acoaxial whirling or receiving chamber, the size of which is increased and decreased as the quantity of fuel entering same is increased and decreased, respectively, produces results which are uniformly excellent for all operating conditions. In addition, the correlation of this feature with the primary air directing means comprising annular wall 6 and annular member 36 increases both the rapidity and the extent mixture in a space or combustion chamber of short length in the direction of gas flow therethrough. However, the primary aixdirecting means improves the operating characteristics of any type of atomizing burner, and its use is not in any manner limited to the particular type of burner herein shown and described.

The feature of mounting the valve element 1| in and for axial movement relative to a member Y fixed in the nozzle portion of the burner for movement therewith is also of particular importance as it prevents an appreciable movement of the nozzle portion relative to the valve element and thereby the variation in the degree of fuel feedV and/or orifice opening which always occurs when the nozzle valve is carried by the relatively cool body portion of the burner.

The invention is applicable to fluid fuel burners generally, and although a particular applica- :tion has been illustrated and described in detail, it should be understood that it is not desired to limit the invention to the exact details of construction herein shown and described, as various modifications within the scope of the appended claims may occur to persons skilled in the art.

It is claimed and desired to secure by Letters Patent:

i. Combustion apparatus comprising a burner having a nozzle portion provided with an orifice effective to produce a diverging fuel spray, means defining a chamber surrounding said burn.- er and including an inner annular air diverting and directing wall shaped and arranged to forni with the nozzle portion of the burner an inner annular air passage of decreasing cross sectional area in the direction of air iiow therethrough, and an inner member -surrounding the orifice end of said nozzle portion in passage forming relation therewith, said member being axially spaced from the inner peripheral edge of said annular wall in the direction of air ow to divert and direct a portion of the air issuing from said inner passage inwardly against said fuel spray at a point immediately adjacent said orifice.

2. Combustion apparatus comprising a burner having a nozzle portion provided with an orifice` eifective to produce a dlverging fuel spray, means defining a chamber surrounding' said burner and including an inner annular air diverting and directing wall shaped and arranged to form with the nozzle portion of theburner an inner annular air passage of decreasing cross sectional area in the direction of air flow therethrough and an outer annular wall forming with said inner 'wall a 'surrounding annular air passage which merges with said inner passage adjacent the orice end of said nozzle portion, and an inner member surrounding the orifice end of said nozzle portion in passage forming relation therewith, said member being axially spaced from the inner peripheral edge of said inner wall in the direction of'air flow to divert and direct a portion of the air issuing from said inner passage inwardly against said fuel spray at a point immediately adjacent said orice.

3. Combustion apparatus comprising a burner having a nozzle portion provided with an orifice effective to produce a diverging fuel spray, a tubular radiant heat reflecting shield surrounding the nozzle portion of' said burner, means defining a, chamber surrounding said shield and including an inner annular air diverting and directing wall shaped and arranged to form with to the orifice end of said nozzle portion, said member having a diameter approximately equal to the diameter of the inner peripheral edge of said inner wall and being axially spaced from said edge in the direction of air ow to divert and direct a portion of the air issuing from said inner passage inwardly against said fuell spray at point immediately adjacent said orifice.

4. Combustion apparatus comprising a burner having a nozzle portion provided with an orifice effective to produce a diverging fuel spray, a tubular radiant heat reilecting shield surrounding t-he nozzle portion of said burner, means dening er Y 8 a chamber surrounding said shield and includ ing an inner annular air diverting and directing wall shaped and arranged to form with said shield an inner annular air passage of decreasing cross sectional area in the direction of air ow therethrough, said shield having at its orice end a plurality of inwardly bent lingers engaging said nozzlel portion adjacent said orifice and a plurality of axially extending ngers, and an annular member carried by said axially extending ngers in surrounding passage forming relation with respect to the oriiice end of said nozzle portion, said member -being axially spaced from the inner peripheral edge of said annular wall in the direction of air ow to divert and direct a portion of the air issuing from said inner passage inwardly against the fuel spray at a point immediately adjacent said oritlce. A

HANS A. ALTORFER.

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