US1887015A - Means for the combustion of pulverized fuel - Google Patents

Description

Nov. 8, 1932;

E w. GREEN ET AL MEANS FOR THE COMBUSTION OF PULVERIZED FUEL Filed March 18, 1929 2 Sheets-Sheet 1 Edward Wflham Green George. Wad ham Ur'vH'mnk Doo/Lcl Dunn Nov. 8, 1932. E. w. GREEN ET AL MEANS FOR THE COMBUSTION OF PULVERIZED FUEL Fiied March 18, 1929 2 Sheets-Sheet 2 Edwavd \Wh am Greer.

g o oooo oo o O O O O O O O O O O O O O O O O O O O O O O O fieovqe Rokiham Unrncnk Dcwc) Dunn jr/ffdjgy Patented Nov. 8, 1932 UNITED STATES n-Arsnr EDWARDWILIZIAI GREEN, GEORGE RODHAM UIITEANI, DUNN, OFLONBON;

ENGLANDQASSi-GNOBS 1TOTHEiBUELLCOMEBUSIIQN COMPANY'LIMITED, OF LONDON,

ENGLAND i MEANS FORTHE GOMBUSTION OF"PULVERIZED"FUEL' App atim fi March 18, 1929, r M33755, nd in; Great Britain April 13 ,rc1928.;

This invention relates to improvements in the combustion of pulverized fuel and means therefor, has particular reference to burners suitable for heatingsteam boilers andhas for its object the more Complete combustion of the fuel than has been possible heretofore, saidcombustion being effected by simpler and more reliable apparatus than has hitherto been used for thispurpose;

The invention consists in the arrangement within a stream of pulverized fuel and its carryingfluid, of a core in the form of a stream of'air, and about said stream of pulverized fuel and its carrying fluid of'an envelope in the form of a streamof air, means being provided for constituting said streams and for proportioning the volumes and Velocities of the various streams relative the one tothe other so as to ensure effective inter-.

amount of air for complete combustion in the combustion chamber.

y In the drawings Figural is alongitudinal section of an improved structure adapted to operate in ac cordanee with this invention, said structure being arranged with a Howden forced draught furnace front so asto constitute a burner; a a

Figure 2" is a sectional end elevation of the structure illustrated in Figure 1' taken on the line 2-2 of that figureand looking in the direction of the arrow; and

Figure 3; is an external'end elevation of'the Figures 1 and 2; c

From thedrawings it will be seen that the inventionis carried into, practical effect by discharging through the furnace front into thecombustion chamber the pulverized fuel and its carrying air as a tubular stream from an annular conduit a, the stream of air forming the core being delivered through the tube b whilst the air forming the envelope is delivered through the perforated plates 0, d, e, f, g, h, and 2' as described hereinafter.

The tube 7) is supplied with air from the Howden or other preheater associated with the furnace front through the flexible tube 6 and the end of the tube 6 external to the furmingling of the fuel with the requisitev parts associated with the Howden front in' means of the finger operable nut 6 and is provided with a'window b to enable the colour and nature ofthe flame to be observed whilst the burner is inoperation. y

In order that the pulverized fuel shallibe venly distributed in the carrying fluid and the mixture shall be evenly supplied to the annular conduit a, the fuel and its carryingfluidare tangentially introd ed "f om, the supply nduit j int a chamber is adapted to'produee a whirling stream from which chamber the mixture is centrallydisc'harged into the, annular conduit a between the tube bandv a tube Z'attached to th W ir hamber i v To ena the mos desirab e a mixture. between the fuel; and its carrying air to be obtained andto, adjust the quantity delivered to the annular conduit (l the whirl chamber A: 1s provided" with a lip is about its discharge orifice, said lip k projecting into the whirl an berv fsueh istan as will ens r th the requirediconditions are complied with,

A deflector n is mounted upon the end of the tube 6 remote from-the cover plate 6?; said deflector cooperating with the adjacent end of the tube Z; The tube Z7 is slidably mounted in the whirl chamber 70 and tube Z, so that the deflector n can be displaced longi-v tudinally relatively to theend of the tubel as q ed, th aid tub 'b i g ur d i the most satisfactory position by means. of a screw m.

The above recited structure is mounted w t n a tubu ar xten ion. 0 on a plate p wh ch an e substitut d f r he-or inary fire door of the furnace front to, which the burner is to be applied 1 As illustrated the plat 2? has awindow p provided to enable the colour and nature of the flame to be observed? during operation of the furnace.

the arm r construction illustrat d i 160 Figure lthe structure is applied to an ordinary Howden forced draught furnace front for a boiler the said structure being located in the aperture through which firing with solid fuel is normally effected and to produce the envelope of air for the annular stream use is made of the Howden draught arrangements to supply air to the firing hole g and also to the ash pit 1'.

The supplementary plate 0 distributes the air supplied to the firing hole 9 through the port g under control ofthe valve 2, the supplementary plates d, h and 'i distribute the air supplied to the ash pit 1" under the control of the side valves usually employed with Howden forced draught fronts, the ordinary known perforated plate 0 distributes the air supplied through the port 0 under the control of the valve 2 and the ordinary known perforated plates f and g dist'ribute the air supplied to them through ports and under the control of the Valve 2.

The deflector n cooperates with the adjacent end of the tube Z to deflect the annular stream of fuel and air issuing from the conduit a directly into the path of the air issuing from the perforations in the plates 0, d, e, f, g, h, and i.

In order that the deposit formed during operation of the burner may be removed through the ash pit r in the ordinary way the plate d may be hung upon hooks al so as to permit of its deflection or removal as required during cleaning operation.

The perforations in the plates 6, f and g are of such size as will pass the requisite amount of air to promote complete combustion of the fuel introduced. Otherwise the parts 6, f and g aresimilar to the equivalent parts usually used with coal fired Howden forced draught furnace fronts.

Obviously, the proportions of .air supplied during combustion vary with .the fuel employed and the conditions under which combustion takes place. It has been found that with a burner having a two inch connection to the central tube 6 satisfactory results can be obtained when 400 pounds of pulverized North country steam coal are fed per hour through the annular conduit a together with about 1,750 pounds of air at a temperature of about E, about 380 pounds of air at a temperature of about 200 F. through the tube 6 and about 3,250 pounds of air through the plates 0, (Z, 6, f, g, 72 and 2' at a temperature of about 350 F. inasmuch as this air is heated by the plates.

Those skilled in the art will recognize that some variations of considerable magnitude may be required to operate such a burner satisfactorily, such alterations being determined in the ordinary way such as by the CO meter or the appearance of the eflluent from the funnel. To enable the required variations in proportions to be-obtained means of ordinary form are provided for regulating the quantity of fuel, the amount and temperature of the carrying fluid therefor and the amount and temperature of the air passing through the burner.

As illustrated, the Howden front is shown now with the usual regulating valve 2 but for purposes of clearness the side valves provided to control the flow of air to the ash pit are omitted and such valves as may be employed to control the flow of air to the central tube 6 and the combustible mixture through the tube 7' are also omitted.

We claim z 1. An improved burner for air borne pulverized fuel having in combination a combustion chamber, a furnace front comprising a front wall and a perforated rear wall spaced therefrom, a main tube carried by said front penetrating said walls, a central tube in said main tube leaving an annular passage about said central tube, a whirl chamber located eX- ternally of said combustion chamber and carrying said central tube and adapted and arranged to deliver a whirlin stream of air to said annular passage, a de ector on the free end of the central tube within the combustion chamber, means for supplying air to the space between said walls, means for supplying air to the central tube and means for supplying air borne pulverized fuel to the said whirl chamber.

2. An improved burner for air borne pulverized fuel, as claimed in claim 1, said central tube being adjustable along the longitudinalaxis of the main tube to vary the position of the deflector and means for securing the central tube in any position to which it may be thus adjusted.

3. An improved burner for air borne pulverized fuel, as claimed in claim 1, including a 1i interiorly arranged about the discharge ori cc of the said whirl chamber.

41. An improved burner for air borne pulverized fuel, as claimed in claim 1, including a displaceable cover upon the end of said cen- Eral tube remote from the combustion cham- 5, An improved burner for air borne pulverized fuel, as claimed in claim 1, in which the said central tube is adjustable with respect to the whirl chamber, whereby the deflector may be adjusted relatively to the end of the said annular passa e.

EDWARD WILLI M GREEN. GEORGE RODHAM UNTHANK. DAVID DUNN.

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