US 1722495 A
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Description (OCR text may contain errors)
W. B. CHAPMAN PRODUCER GAS BOILER July 30, 1929.
Filed July 29, 1926 2 Sheets-Sheet 1 D. be /M; M
ATTORNEYS '7 i INVENTOR 3 22 21 BY 6%,,
Z0 Z5 Z1 2 July 30, 1929. w. B. CHAPMAN PRODUCER GAS BOILER Filed July 29, 1926 2 Sheets-Sheet 2 INVENTOR Ma. Q. CZ
I A ATTORNEYS Patented July 30, 1929.
WILLIAM B. CHAPMALL OE JACKSON HE IGHTS, NEW YORK.
Application filed July 29,
The invention although applicable to boilers in general is especially designed to enable the cheapest grade of fuel to be employed in boilers used for heating purposes, wherein the undue amount of smoke produced by the cheaper grades of bituminous coal, and the tendency of this coal to burn irregularly with zones of high temperature which produce many clinkers, heretofore have compelled the use of more expensive fuels, especially in small boilers.
The invention aims to enable the combustion of fuels to be carried on under such conditions as will avoid the necessity of introducing air in quantities much in excess of those which are 'proper to complete combustion, avoid non-uniform conditions of combustion within the fire bed, such as are caused by nonuniform fuel distribution, non-uniform distribution of the blast over the difierentparts of the fire bed, non-uniform ash removal from different parts of the ash bed, blow holes, etc., to the end that the cheaper grades of bituminous coal may be satisfactorily employed.
According to the present invention the boiler is heated by means of a deep fire bed which generates producer gas, the firebed being several feet in thickness as contrasted to ordinary practiceof seldom more than one foot, the fire bed being conditioned by means of an agitating member which rotates around slowly in the bottom of the fire bed so as to spread the fuel out evenly over the fire bed and pack it against the walls, eliminate blow holes,
grind up clinkers and eject the ash; this agitating member being employed in conjunction with a continuous fuel feed, preferably of the underfeed type, whereby the fuel may be fed to the fire bed at the proper rate, the fire bed properly conditioned and the ash removed at a rate corres onding to its rate of production, thus enab ing gas to be produced which will be uniform asto quality and quantity. The gas thu 's produeed is then collected and mixed with secondary air and completely burned within the boiler, the uniform production of gas as above mentioned making it possible to feed inthe proper amount of secondary air which will be required to complete combustion.
1926. Serial No. 125,618.
F urthen objects and advantages of the in- VQIItlOIl w ll be in part obvious and in part spec fically pointed out in the description hereinafter contained which taken in conjunction with the accompanying drawings','discloses a boiler adapted to operate in accordance with the invention; such disclosure, however, should be considered merely illustrative of its principles. In the drawings:
Fig. 1 is a central vertical sectional view of a boiler constructed in accordance with the invention.
Fig. 1 is a detail view showing a device for automatically regulating the amount of secondary air.
Fig. 2 is a horizontal section taken on line 22 of Fig. 1.
Fig.- 3 is a horizontal section taken on line 3-.-3 of Fig. 1.
Fig. 4 is a. deta1l section taken on line 4-4 of Fig. 2.
Figs. 5 and '6 are diagrammatic views illustrating the shape of certain blades used to assist in feeding the fuel.
In the illustrated embodiment of the invention I have shown a boiler having inner and outer cylindrical shells 1 and 2' which enclose the chamber 3, which contains the fire bed, and also a secondary upper combustion chamber or zone 4, the shells 1 and 2 being provided with upper domes 5 and 6 respectively th'ereby affording heating surfaces both above and around the burning gases.
As shown the fire bed is supported upon a grate denoted generally by numeral 7. lhe
' fire bed is conditioned by means of an agitating member 8 which is illustrated as extending substantially diametrically across the bottom of the fire bed and which rotates with regard to the fire bed. The agitator is both up and out stroking in its action whereby the rotary. motion above mentioned causes an upward undulatory motion substantially throughout the fire bed, the agitator being shown as provided with an incllned forward surface 9 (Fig. 4) to facilitate its upstroking action. The outstroking action of the a itating beam tends to crowd outwardly any arge clinkers which may form and the inner shell 1 of the boiler preferably is provided with an annular wear ring 10 opposite the ends of the agitator, whereby clinkers may be ground up between the ends of the agitator and such wear ring. This wear ring 10 furthermore is provided with inclined ridges 10 (Fig. 2) which prevent the firebed from turning around bodily with the agitator. 4
In the illustrated form of the invention, the fuel is fed from underneath into the fire bed through a hollow column-11, passing up centrally through grate 7 and fixedly connected to the agitating member so as to turn the latter.' The hollow column 11 is shown as supported and rotated by the ratchet gear 12 which in turn is rotatably supported upon the hub 13 of a large gear 14 which latter runs on a ball-bearing raceway 15.
The fuel is fed in fromone or more spouts 16 which deliver it to a pan 17 carried by the large gear 14 .and underlying the open lower end of hollow'column 11. The pan 17 also fixedly supports a screw 18 which is enclosed by hollow column 11 and rotates relative thereto whereby fuel fed into the lower end of column 11 is raised through the column and into the fire bed by this screw. The hollbw column 11 preferably is provided with a spiral ledge 19 to assist inelevating the fuel therethrough.
Suitable devices are provided for crowding the fuel into the lower end of column 11 in position to be operated on by the screw. As shown the pan 17 carries a set of blades 20 having instroking curved inner ends 21 thereon which tend to crowd the fuel into the openings 22 (Fig. 1) in the bottom of column 11, and the lower end of column 11 carries oppositely curved blades 23 which cooperate with the blades above mentioned to accenmate the crowding action upon the fuel and thereby assure that the latter is properly en gagedby the lower end of screw 18.
As shown-the pan 17 its blades 20 and screw 18 are rotated faster than column 11 and an intermittent driving mechanism is provided for column 11 which derives its motion from gear 14. In the' present embodiment, an engaging and releasing bar 24 is slidably car- 'ried by lugs 25 and 26 on gear 14, the inner end of the bar engaging the ratchet teeth on gear 12, and the outer end of the bar being provided with a lug 27 (Fig. 1) adapted to engage fixed cam members 28 to throw the bar 24 into and out of engagement with ratchet gear 12. Thus the cam members 28 may be suitably spaced around the periphery of gear 14 to cause the column 11 to be driven through the medium of bar 24 during the desired fraction of each revolution of gear 14.
After being fed up into the fire bed through column 11 as above described the fuel tends to form a moundin the central zone of the fire bed leaving the peripheral zone too shallow. The upper delivery end of column 11, or the central opening in the agitator, furthermore, is preferably of restricted area as which is traveling downwardly to pass out through the grate as ash. The outstroking action of the agitating member, however, which extends substantiallyto'the top of the fire bed, spreads the fuel out evenly over the fire bed and crowds it against the walls thus preventing the air for combustion from passing up through any localized concentrated paths in the fire bed.
In operation gear 14 will be rotated at the speed necessary to feed fuelinto the fire bed at the .proper rate, and cam members 28 will be so spaced that the agitating member 8 is rotated intermittently at such rate as may be necessary to maintain uniform conditions of gas production in the fire bed.
I also prefer to employ in connection with the agitating member a grate which is made adjustable in some suitable manner, so as to permit the effective area of the grate openings as regards ash removal to be altered without substantially affecting the flow of the air for combustion upwardly through the grate. As shown the grate is made up of two relatively movable sections, the upper section 29 being fixed .and being provided with 'concentric series of arcuate grate openings 30 which flare outwardly at their bottoms as shown in Fig. 1,,and lower grate sections 31 are provided in the form of rings which respectively underlie the series of grate openings 80. In the illustrated form of the in 'As the agitating member 8 revolves it grinds up the ash into sizes sufficiently small to pass through openings 30 and the rate of ashdischarge thus will depend union the adjustment of lower grate sections 31. In this way by adjustment of the effective size of the ash openings in the grate as regards ash removal, the operation of removing the ash may be regulated to coordinate it properly with the operations above described with feeding the fuel and conditioning the fire bed. The openings 30, however, at all times are sufiiciently unobstructed to permit the air for combustion to flow upwardly therethrough.
In the illustrated form of the invention ash drops down from the grate on to a rotary table 85 carried by hollow column'll, the ash being confined to the table by an annular wall 36 until it is carried around against a fixed sweep 37 which pushes it into a watersealed chamber 38 from which the ash may be removed in any suitable manner.
Since the space in the neighborhood in the axis of rotation of the agitatingmember through which water-cooling connections to the latter most feasibly can be made, is preempted by the fuel feeding mechanism, I prefer to cool the agitator by causing wet ash to travelover-its face. As shown the upper grate section 29 is provided'with a series of annular troughs 39 which are in communication with each-other through the gaps 40 between grate openings 30, and have suitable water inlet and outlet connections 41 and 42 (Fig. 1) leading thereto whereby the'ash within the troughs is constantly saturated with water. The agitating member 8 furthermore is provided with tongues 43 (Figs. 1 and 4) which extend down into the troughs 39 and thus cause the wet ash to pass upward ly over the inclined forward surfaces 9 of the agitator arms and over its top. As shown the agitating member is open on the underside and also provided with openings 44 (Figs. 1 and'4) in the rear walls of its arms whereby a portion of the air for combustion may pass through these openings up through the hollow beam and out thus assisting in cooling the'agitator.
In the operation of the apparatus thus far described the fuel will be fed in, spread out evenly over the fire bed, the fire bed agitated to promote uniform conditions of combustion therein, and the ash ground up and discharged, all in proper coordination to conform to the rate of fuel consumption, the fire" bed being maintained at substantially uniform depth whereby the producer gas generated will be substantially constant as regards quality and quantity. The hot producer gas is then collected and mixed with secondary air in a restricted. throat to promote uniformity in the mixture. As shown, a refractory arch 45 overlies chamber 3 and is provided with a central opening or mixing throat 46 through which the hot producer gas collected under said arch passes'from chamber 3 intd chamber 4 and is properly mixed with secondary air from a suitable number of air feed passageways 47 leading tangentially into the opening 46 through arch 45. It will beunderstood that one or more of these mixing throats or openings 47 may be employed, accordin to the size of the a paratus. This metho of introducin the air both preheats the air and prevents t e arch 45 from becoming overheated. It also produces a whirl which aids in the proper mixing of the air and gas. The fact that the quality and quantity throat 46 may be maintained substantially uniform as above described, makes it possible .to so control the amountlof secondary air fed in so that approximately the exact amount of air to complete the combustion of the producer gas will be supplied. As shown disks 48 hav- 1ng different sized openings 49 therein, overlie the inlet ends of the air passageways 47,
whereby the amount of' air fed in may be ad- I ing gases pass upwardly through throat 46 to the top of combustion chamber 4 and then turn to pass downwardly through an annular series of fire tubes 50 to an annular gathering chamber 51 at the bottom of the boiler heating surfaces, from whence the spent gases may be led off through a suitable exhaust flue 52 SlFig: 2).
T e re bed may be operated either by air under pressure supplied undereneath the grate and through the secondary air feed passageways 47 or by suction through the exhaust flue 52 in the latter event no pressure for the secondary air feed passageways will be required as the suction will automatically draw in the required amount of secondary air through these passageways as well as draw the primary air up t rough the fire bed.
Preferably. the heating surfaces of the boiler enclose the fire bed, as shown, thus im-' proving the efficienc of the heatinterchange as well as keeping t 1e enclosing walls of the fire bed sufiiciently cool to prevent the undue building up of slag or solidified clinkers thereon.
, A boiler of the above type may be operated with the cheapest grades of bituminous coal without producing undue amounts of smoke and dust since the fuel, being fed in from underneath does not cause fineun'consumed coal particles to pass off with the gases of combustion, and the agitation of the fire bed maintains uniform conditions of gas production such that the proper amounts of secondary air may be fed in to complete com bustion. If-the fuelbed were non-uniform in thickness at different times, or in different zones thereof, or non-uniform as regards pas throat 46, and thus the features of the uniform fuel feed and distribution, uniform fire bed agitation and ash removal are all vital in enabling the boiler to operate successfully.
While a specific apparatus has been described for carrying out the invention, it will be obvious that the invention is applicable to other forms of boilers than the one shown and that many changes may be made therein without departing from the principles of the invention as set forth in the appended claims.
I claim: I
1. A boiler having heat exchange surfaces disposed contiguous to a combustion cham; ber, means for feeding fuel up from underneath into a fuel bed located in the lower portion of said chamber, means for insuring-the formation of producer gas of substantially uniform quality in said firebed, and-means for supplying secondary air within said chamber to the producer gas so formed, to burn the latter in said chamber.
2. The method of heating boilers which I comprises feedingj fuel up from underneath into a chamber having heat exchange surfaces disposed contiguous thereto, maintaining substantially uniform producer gas making conditions in the fuel bed thus formed in the lower part of said chamber, admitting air to the fuel bed and thereby forming pro ducer gas of substantially uniform quality and mixing secondary air with said producer gas in said chamber to complete the combustion thereof. v
3. A boiler having heat exchange surfaces disposed contiguous to a combustion chamber, means for feeding fuel u from underneath into a fuel bed located in t e lower portion of said chamber, means for insuring the formation of producer gas of substantially uniform quality in said firebed, comprising an upstroking agitating member working in the bottom portion of the firebed, and adapted to cause a vertical undulating movement therein, and means for supplying secondary air within said chamber to the producer gas so formed to burn the latter in said chamber.
4. A boiler having heat exchange'surfaces disposed contiguous to a combustion chamber, a grate beneath said chamber adapted to support a firebed, means for feeding fuel upwardly through the central part of said grate, means for insuring the formation of producer gas of substantially uniform quality in said firebed, comprising an upstroking agitating member disposed over said grate and adapted to cause a vertical undulating movement in the firebed and means for supplying secondary air within said chamber to the producer gas so formed to burn the latter in said chamber.
5. The method of heating boilers which comprises uniformly feeding fuel up from underneath into a chamber having heat exchange surfaces contiguous thereto, producing a vertical undulating movement in the firebed and uniformly withdrawing ash comprises feeding fuel up from underneath into the central portion of a chamber having heat exchange surfaces contiguous thereto, to the top portion of a firebed located in said chamber, agitating the lower part of the firebed to produce a vertical undulating motion therein, withdrawing ash from the lower portion of the firebed to cause partially consumed fuel to travel gradually downward around the central upwardly traveling fresh fuel all to form producer gas of substantially uniform quality and'mixing secondary air with said producer gas in said chamber to complete the combustion thereof.
7. A boiler comprising heat exchange surfaces and a combustion chamber disposed symmetrically about a common vertical axis, means for feeding fuel up from underneath into the lower portion of said chamber, said means feeding the fuel symmetrically with regard to said axis, a rotary agitating member sweeping through substantially the entire lower portion of said chamber and also turning substantially about the aforesaid common axis, means also act-ing substantially symmetrically with regard to said axis for supplying secondary air to said chamber.
8. A boiler comprising heat exchange surfaces and a combustion chamber, both disposed substantially symmetrically about a common vertical axis, said chamber having at it bottom, cylindrical firebed enclosing walls and a rotary fire bed agitating member sweeping substantially the entire cross sectional area within said firebedenclosing walls and turning about said axis, means acting substantially symmetrically with regard to said axis for supplying secondary air to said chamber, and for feeding fuel upwardly into the firebed. I
9. A boiler having heat exchange surfaces disposed contiguous to a combustion chamber, means for feeding fuel into a firebed located in the lower portion of said cham ber, means for insuring the formation of producer gas of substantially uniform quality 1n said firebed, and a partition divlding said chamber into a; lower producer gas gathermg chamber and an upper burning chamher, said partition having a central opening therethrough and means associated with said opening forunixing secondary. air with producer gas rising through the opening, said chamber having exit passageways periph erally disposed With regard to said central opening.
10. A boiler comprising heat exchange surfaces and a combustion chamber disposed stantially the entire lower portion of said symmetrically about a common vertical axis, chamber and also turning substantially means for feeding fuel up from underneath about the aforesaid common axis. 10 7 into the lower portion of said chamber, said In testimony that I claim the foregoing, I 5 means feeding the fuel symmetrically with have hereunto set my hand this 24 day of regard to said axis, a rotary up and outstrok- July, 1926.
ing agitating member sweeping through sub- WILLIAM B. CHAPMAN.
CERTIFICATE OF CORRECTION.
Patent No. 1,722,495. Granted July 30, 1929, to
-WILLIAM B. CHAPMAN.
It is hereby certified that error appears in the printedspecification of the above numbered patent requiring correction as follows: Page 4, line 65, claim 5, after the word "'firebed" insert the words "to level the fuel out over the chamber", lines 66 and 67, strikecout the words "to level the'fuel out over the chamber"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.
Signed and sealed this 1st day of October, A. D. 1929.
' M. J. Moore, (Seal) Acting Commissioner of Patents.