US1731446A - Boiler furnace - Google Patents

Description

Oct. 15, 1929. J. VAN BRUNT BOILER FURNACE Filed Dec. 1925 Patented Oct. 15, 1929 UNITED STATES PATENT OFFICE JOHN VAN BRUNT, OF FLUSHING, NEW YORK, ASSIGNOR TO INTERNATIONAL COM- BUSTION ENGINEERING CORPORATION,

DELAWARE OF NEW YORK, N. Y., A CQBPORATION OF BOILEB FURNACE Application filed December This invention relates to boi1er-furnaces and is especially useful where the fuei to be burned is in tinely divided frm,'such as pulverized coal.

One of the primary objects of the invention is to provide an improved arrangcncnt ot' boiler-furnace in which the boiler tubes define the combustion space and are primarily subjected to radiant heat, whereby a large quantity of steam can be generated in a very small installation; whereby the re- 'ractories may be very much lightened and chcapened; and whereby Operating difficulties incident to refractory combustion chambers are very iargely avoided.

Other objects and advantages of my invention will be set forth hereinafter as they will be more readily understood in connection with the description of the invcntion.

How the foregoing, together with such other objects as may be incident to my in- Vention are realized is illustrated in preferred form in the drawing which is a vertical section thru a boiler-furnace embodying the preferred form of my improvcments.

Reterring now to the drawing, A denotes the combustion space. The front, sides and top of this combustion space is defined by the water walls a, I) and e. The bottom of the combustion space is defined by a water screen d and the rear of the combustion space is de- "fined by a water wall e.

The side water walls are composed of vertically extending tubes 7 having longitudinally extending fins 8 welded or otherwise secured to opposite sides thereof so that the tubes and the fins co-operate to constitute in' effect a continuous metallic wall. The end portions of the tubes 7 pass outwardly thru the side walls and are connected to the upper and lower headers 9 and 10 respectively,

these headers being somewhat inclined from front to rear. The front water wall s composed of tubes 11, such tubes also having ngitudinal fins, which, however, are interi ripted at intervals to provide gaps 12 for admission of air as Will further appear. The top water w'all c is composed of tubes 13 which are also equipped with fins, these fins, however, being interrupted as indicated at 17 which have fins 18 extending for approximately one half ot their length.

The tubes 13 of the top wall extend from the drum 19 somewhat downwardly to the header 20 into which the upper ends of the tubes v 11 of the 'front water wall are eX- panded. The lower ends of the tubes 11 are expanded into the header 21 into which header, also, the lower ends of the tubes 16 are expanded. The upper ends of the tubes 16 are expanded into the header 22 and the tubes 17 extend from this header to the drum 19. 4

Suitable downcomers23 lead from the mud drum 24 to the header 21, supplying this header with water. The circulation, therefore, is downwardly from the drum 24 to the header 21 and thence upwardly thru the Water screen, front and rear water walls and thru the top wall, to the drum 19, the drum 19 being connected to the drum 24 by a bank of tubes g, certain of the tubes of which act as downcomers from the drum 19 to the drum 24, thus completing the circuit of circulation for the water screen, the front and rear water walls and the top wall. The unit com'prised of the drums 19 and 24 and the tubes g functions also as an economizer'.

Downcomers 25 lead from the drum 24 to the lower ends of the headers 10, suppl ing such headers with water. The tubes o the side walls constitute upcomers to the headers 9, which headers are connected as at 26 with the drum 19, thus providing' a circuit circulation for the side walls.

The drum 24 is set about midway of the height of the combustion chamber, to the rear thereof. That is to say, the drum 24 is lo- 'cated about opposite the upper end portions of the fins 18. The rear sheathing wall 27 also terminates at about the same point. Thus the space between the drums 19 and 24 constitutes the outlet from the combustion space for the Wastc products of combustion. The bank of tubes g extend within this space and consequently these tubes constitute a single pass boiler unit, with the tubes of comparatively very short length.

The pulverized coal with a portion of the air required for combustion is admitted downwardly thru the row of burners 15, the fuel being burned with a reverting or U shaped fuel and flame stream, with combustion being completed before the bank of tubes g is reached, except possibly at very extreme ratings. The balance of the air required for combustion is admitted thru the rows of damper control inlets 28 in the front sheathing wall 29, which inlets are located opposite the spaces 12 provided by the interruptio1 of the fins on the tubes of the front water wa In View of the fact that the water walls and screen define the combustion space and are subjected to radiant heat, they transmit heat at a very high rate and are, thcrefore, capable of generating a Very large quantity of steam. By the 'same token they have a tendency to lower furnace temperature and, therefore, to meet each condition I first cut down the amount of evaporating surface and increase the furnace temperature head by highly preheating the combustion air supplied thru the front wall as will further appear. The evaporating surfaces are so calculated with relation to the fuel to be burned in the installation that the waste gases leave the combustion space at a very high temperature indeed. They impart some of their heat to the small single pass unit g, but still leave said unit at a very high temperature so that What I claim is:

1. The combination with a. finely divided fuel burning furnace, of a boiler including two rows of substantially upright tubes defining combustion space, header means at the lower end of the tubes of each row, a row of tubes extending across 'the lower portion of the furnace and conncting the header means of an upright row with the header means of the other uprght row, economizer means n- I cluding connected upper and lower drums, the upper ends of the upright rows of tubes being connected to said upper drum and downcomer means connecting said lower drum to one of the said headers, and the lower drum being at a level above the lower headers.

2. The combination witha finely divided fuel burning furnace, of a boiler including two rows of substantially upright tubes de V dwncomer means connecting on'e of said drums with one of said headers, and the lower drum being at a level above the lower headers. In testimony whereof, I have hcreunto signed my name.

JOHN VAN BRUNT.

they may impart a high degree of heat to the air passing thru the preheater 30 located in the oftake 31 of the installation. The air is .forced thru the heater, as by means of a fan (not shown) and enters the breaching or casing 32, such casing being'shaped so as to provide a compartment or space 33 in front of the front wall.

The high degree of preheat obtained insures proper combustion by virtue of the increase in furnace temperature head, thus overcoming the chilling action of the Water Walls and screen. I

It will be seen that the arrangement of boiler is small and that the installation, as a whole, is quite simple and compact,both as to ground area covered and vertical height required. The sheathing is very light and simple in construction as Compared to the refractory walls which would otherwise be required, in which connection it will be understood that the sheathing as shown in the drawings is exaggerated as to thickness.

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