US1883789A - Burner - Google Patents

Description

D. J.'lRlSH Oct. 18, 1932.-

BURNER- Filed oct. 5. 1928 lll J. lRISH A IORNEY l rlllllllll Patented Oct. 18, 1932 STATES Arr-:Nr OFFICE i nAvIn a." IRISH, orv RIQIIMOND, STATEN ISLAND, NEW YORK, ASSIeNOny To FOSTER WHEELER CORPORATION, or NEW YORK, N. Y., A CORPORATION OF NEW YORK BURNER .Application Iled October 5, 1928. Serial No. 310,481.

The invention relates torburners for powder ed fuel and more Y.particularly to burners for burning a variable quantity of fuel.

The combustion ofA fluid fuels has the distinctive advantage :over the combustion of solid fuels in that the rate of combustion can Vbe quickly and easily varied over a. wide range vto accommodate varying demands for heat and'power. In thus varying the quantity and volume of fuel, in the types of burners heretofore used, the'velocity of the fuel adjacent the peripheral edge of the fuel outletr was permitted to' vary with changing rates 'of combustion and` to thereby affect the effectiveness with which the'fuel was mXedand agitated with the adjacent air. Consequently, under some conditions of operating Vand 'where powdered fuel was used, the parts of theffuel more remote from thezair supply did not become thoroughly mixed with the air. during the passage through the combustion zone. Moreover, in cutting down the fuel supply, particularly burning suspended,powdered fuels, there was danger of the flame being extinguished vbecause of too great a diffusion of the fuel. Moreover, if in burning pulverized fuel, the burner be closed entirely it and thesupply conduits may become filled and plugged with fuel.

An object of the invention is to provide a powdered fuel burner in which the volume of fuel may be varied independently ofthe vel locity of the .fuel or, in which the velocity may b-e varied independently of the volume or rate of supply of the fuel.

Another object of the invention is to provide a burner in which the velocity and 'volume ofthe fuel may be varied, and in which a minimum velocity andfvolume' or rate of supply is always maintained and the burner is-ensured against` a complete, blocking of the fuel supply. y ji Further objects and features of the invention areto provide a burner in which-a small, concentrated flame may be obtained at 'low rates of fuel consumption; to provide a variable feed burner in'which the size of the minimum flame may beadjusted; andto provide an effective and 4efficient air and fuel mixing means, and means for .easily and conveniently varying the rate of supply of the fuel. Y a

Y, .With theseand other Objects in view, which will more fully appearV from the following description, the invention comprises the burner described and set forth in the following vspecification and claims.

The various features of the invention are illustrated in the accompanying drawing, in which t Fig. 1 is a longitudinal sectional View of a burner embodying theinvention and showing it mounted in the wall of a furnace, and

' lT ig. 2 is a cross sectionalview of the kburner taken on line 2 2 of Fig. l.

ln .the present invention the fuel is `sup- 1 plied through `a burner nozzle which, near its v outietend, is divided by means of an annular partition co-aXial with th-e nozzleV into an annular'channel, which is open at all times, and an inner passage, which may be ypartly .Or entirely closed tol control the rate ofsupply of fuel. Y The outlet edge fof the burner is vsharply inturned'or contracted immediately beyond the outer annular passage lso vas to direct the fuel passing .therethrough inwardly towards the axis of the burner.

When the inner passage is .nearly closed the centrally deflecting effect of thecontracted outlet edge of the burner hasa imarked effect in deflecti-ng theannularstream of fuel ra-Y dially inwardly, but when the central passage isopened wide this edect is modified by the larger volume of fuel passing through the central part of theapparatus. The position of the partition may, however, be varied lon,- gitudinally of the burner'to bring the outlet edge of the annular .partition and. of the outer annularpassage nearer to the outlet edge 'of the burner to deflect the annular stream more, sharply'and thus increase the converging edect, or it Vmay be drawn farther therefrom to decrease this effect. In this mannerthe size andshapeof the minimum y fiamemay be adjusted Vto a vburner setting. Suitable Vanes are provided in the annular passage and thefcentral passage to give'the fuel a rapid rotary motion as it 'issues from the burner and to thus give it a tendency to nozzle or conduit 10 and having a contracted throat portion 13 and a gradually expanding outlet let which diverges until it meets the inner surface of the nozzle 1l. Immediately beyond the edge of the expanding outlet 14 of the shell 12, the burner nozzle diverges and expands, as at 15, to an enlarged cylindrical part- 1G. At the outlet edge of the cylindrical portion 16 an inturnedV or inwardly curved rim portion 17 is secured by vmeans of screws 18. rlhe rim portion 17 may, of course, be made integral with the burner nozzle but, inasmuch as it is exposed to the radiated heat ofthe furnace, as well as to the erosion of the fuel particles, and is thus subject to more rapid wear, itis preferable to make it removable, as shown, so that it may be easily and quickly renewed and replaced.

As the fuel passes through the expanded portion 15 of the cylindrical part 16 it is separated into an outer annular stream and a partition comprising an inner stream by means of an expanding or frusto-conical partition 19 co-axial to the of the nozzle. The two streams are maintained separate in passing through the cylindrical part 16 of the burner by means of a cylindrical portion i 20 of the partition. The cylindrical wall 20 is spaced from the wall of the burner nozzle and supported co-axially of the burner nozzle by means of longitudinally curved radial vanes 21 between the cylindrical portion 16 of the burner and the cylindrical wall portion 20. The longitudinal position ofthe vanes 21 and cylindrical wall portion 20 may be varied and adjusted by means of longitudinally disposed rods 22 secured to the rear edges of the vanes 21 and extending to the exterior of the nozzle through longitudinal openings in bosses 23 in the expanding part 15 of the nozzle. he projecting ends of the rods 22 are provided with eyelets 211 by which they may be grasped and moved longitudinally. l/Vhen the cylindrical wall portion 20 has been moved to the desired adjustment its position is fixed by means of nuts 25 which are threaded onto the rods 22 and abut the ends of the bosses 23 through which the rods 22 extend. The rods are further prevented from longitudinal movement by means of set screws 26 projecting through the sides of the bosses. By adjusting the position of the rods 22 and wall portion 20, the

annular stream of fuel issuing through the passage between the wall portion 20 and the nozzle wall 16 is brought into more or less immediate contact with the inturned edge member 17, and thus caused to deflect more or less i sharply inwardly towards the axis of the burner.

The annular passage between the annular wall portions 19 and 2O and the wall of the nozzle is open at all times and unobstructed to the passage of fuel. The passage of fuel centrally of the annular walls 19 and 20 is, however, controlled by means of a longitudinally movable valve 27 having a cylindrical portion 28 which is guided and supported on the inner edges of curved vanes 29 projecting inwardly of the annular wall portions 19 and 20. The forward end of the valve 27 is closed by means of a vtapering or frusto-coni-V the cylindrical wall 28 andthe conical wall 30 tightly against the block 31 which is stopped against the enlarged part of the valve stem 33. The space within-the open end of the cylindrical wall 28, which is exposed to the heat of the furnace, is filled with a refracl tory material which is held in place by an anchoring ring 3 6.

It will be obvious that as the valve 27 is moved forwardly towards the Contracted end of the wall 19, the area ofthe passage and the rate of supply of fuel are reduced. However, even though the passage be entirely closed by drawing the valve 27 forwardly until the cylindrical wall 28 meets the con- Y tracted forward edge of the wall 19, the annular passage between the cylindrical wall 2O and the inner surface of the nozzle remains open. Accordingly, complete stoppage of the burn er, such as might result in clogged conduits, is avoided and also sufficient fuel i" is supplied to prevent the flame from being extinguished. lWhen the valve 27 is in closed position, the annular stream o-f fuelpassing between the cylindrical wall 2O and the wall of the nozzle is deflected inwardly by the inturned edge 17, thus giving the fuel stream a converging shape and holding it within a small compass of intense heat, so that the fuel will not become too widely dissipated and extinguished by too rapid cooling in the large volume of surrounding air. The vanes Y 21 give the issuing annular jet o-f fuel a ro- .tarylmotion which ensures thorough mixing with the surrounding air. j Y

Then the valve 27 is moved rearwardly towards open position, a much larger and stronger volume of'fuel passes through the inner passage in an annular'sheet between the wall 28 of the valve 27 and the annular wall The volume of yfuel issuing through this passage is given a rotaryy motion by the vanes 29 which are curved in a direction opposite to the curvaturel of the vanes 21 so as to give the inner and outer annular streams greater turbulence as they issue from the edge 17. yI`he rotary motion of the inner fuel stream gives it a spreading action which causes it to expand into the surrounding air currents after leaving the burner to thereby supply sutcient air for the increased quantity of fuel.

By adjustingthe position of the annular wall and of the valve 27 the various effects Y noted above may be modified to give any desired condition of operation.

The valve 27 may be actuated in its longitudinal movements iny any desired manner.

In the means shown in the accompanying drawing, the valve stem'33 is guided'in a col- .o lar 37 supported centrally'in the shell wall 14 by means of vanes 38. The forward end of the valve stem is connected by means of a link 39 to a crank 40, one endfof which is journaled on a pin 41 threaded through the wall of the nozzle 10, and the other end of which is reduced, as at 42, to pass through a bearing 43 diametrically opposite to the pin 41. The crank is extended beyond the reduced portion 42 and is squared at 44 to receive an actuating handle 45 by means of which the crank may be turned to move the valve stem 33 and valve 27 forwardly or rearwardly on the vanes 29. The crank 40 may be secured in any position by means of a nut 46 threaded on the end 47 of the crank 40 and projecting beyond the squared portion 44. The crank 40 is of such dimension as to give the valve 27 sufficient movement to closev it against the contracted edge of the wall 19 in any position of adjustment of the latter so that the valve 27 may, at all times, be moved to entirely closed position.

The nozzle 11 may be mounted in a furnacey sage of air through the inlets 52 is governed by means of a damper 53 having openings 54 which may overlap the openings 52 to a greater or less extent. The angular position of the plate 53 and openings 54 may be adjusted by means of a collar 55 secured to the plate 53 at its inner edge and encircling the outer wall 11, and provided with a handle 56. `The collar 55 may be secured in position by meansy of a thumbscrew 57.

Through the above invention, a burner is provided by means of which the velocity of the fuel may be maintained independently of its rate of supply, and in which either the rate of supply or the velocity of the fuel may be varied independently of each other. The burner also provides means whereby the size and type of the flame issuing therefrom may be, controlled, and whereby the shape and di mension of the flame may be automatically regulated to produce the conditions most suitable for each rate of combustion of the fuel.

As changes of construction could be made within the rscope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall bel interpreted as illustrative and not in a limiting sense.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is :f

1. A pulverized burner which comprises a tubular nozzle wall having an enlarged por* tion near its outlet end and an inturned outlet edge,'an.annular inner wall in said enlarged portion of said nozzle wall and forming an inner passage, and said annular wall having an enlarged portion and a contracting portion, supporting and deflecting vanes between said nozzle wall and said inner annular wall, deflecting and guiding vanes within said inner passage at the enlarged portion of said annu-k lar wall, and a valve guided by said guide vanes and movable longitudinally in said inner passage.

2. A pulverized burner which comprises a tubular nozzle wall expanded towards its outlet end and having an inturned outlet edge, an inner wall within said expanded portion of said nozzle wall, said inner wall having a larger diameter part and a contracting .portion and forming an inner passage, supporting vanes between said inner wall and said enlarged portion of said nozzle, inner my hand. v

` DAVID J. IRISH.

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