US1830181A - Steam generator - Google Patents

Description

Nav. 3, 1931.

w. R. wooD STEAM GENERATOR Original Filed Aug. 20, 1925 ATTORNEY Patented' Nov. 3, 1931 UNITED .STATES 'PATENT oEElcE WILFRED R. AWOOD, OF LONDON, ENGLAND, ASSIGNOR TO yINTEBLNA'IIONAI GOMBUS- TION ENGINEERING CORPORATION, OF NEW YORK, N. Y., A. CORPORATION OF DELA- WARE L 1 Original application filed August 2Q, 1925, Serial iNo. 51,294'. Divided and this application illed September STEAM GENERATOR 16, 1927. Serial No. 219,858.

This invention relates to steam generators of the type in which the boiler is furnace shaped, i. e., it is its own furnace whereby' the evaporating surfaces are subject to ra- Bfdiant heat and very high capacities are obc August 20th, 1925.

. One of thel primary objects of my invention is to burn thev fuel effectively in such a gen- .eratoln Another object is to not only effectively .liberate heat units in such an installation but also to effectively utilize the same. l

How the foregoing, together with such other objects and advantages as may hereinafter appear, or are incident to my invention,

are realized, is iltustratedvin preferred form I in the accompanying drawings, wherein- VFig. 1 is a vertical section through a boiler `installation embodying my invention, certain of the parts appearing in elevation,

Fig. 2 is a fragmentary section t'aken on 'i the line 2-2'of Fig. 1, and

Fig. 3 is a diagrammatic plan view illustrating the disposition ofthe nozzles for in troducing'fuel into the combustion chamber.

Inv the ldrawings I have illustrated a furnace shaped boiler A. the side walls of which are comprised of sets of tubes 3, one of which only appears in the drawings; the front wall by a set of tubes 4: and the rear wall ,by the bank of tubes 5 of the upright boiler unit 6.

The tubes of the sets of tubes 3, 3 and 4 are preferably provided with longitudinal fins as are also the tubes of the innermost and outermost rows of tubes of the bank of tubes 6. The tubes are arranged4 so that 'the 'I fins 'substantiallyl abut vwhereby a ,wall is formed. Certain of the fins are interrupted' to provide inlet openings 7 for a purpose hereinafter appearing.v The ins of the innermost row of tubes of the bank 5 extend from thelower drum of the boiler unit 6 to a point short of the upper drum and the tins of the outermost row extend from the up-v combustion chamber passing throu h the outlet 8 at the top, do-wn over the tu s of the bank of tubes 6 and out through the oiftake 9 at the bottom into the stack or iue 10 under iniuence of draft. Ity will be noted that the fins of the innermost row are of such extent that such row constitutes the rear wall of the furnace shaped boiler.

A set of tubes 11 extends across the bottom of the boiler thus formed and constitutes a water screen for the boiler, the tubes being relatively widely spaced to permit gravitating refuse particles to pass therebetween. A

set of tubes 12 extends -across the top of the boiler. It is to be noted that the bottom tubes 11 incline lupwardly toward 4the front wall and that the top tubes incline upwardly toward the boiler unit 6 and the bottom set of tubes is connected at one end intothe header 13 which, in turn, is connected with the lower drum' of the unit 6 by means of downcomer tubes and at the other end into the bottom header 14 of the set of tubes 4. 'The top lset of tubes 12 is connected at onel end into the upper header 15 of the set of tubes 4 and at the other end into the upper drum of the unit 6. The tubes 3 of the side walls are connected at their lower ends into headers 16 and at their upper endsinto headers 17. the lower'headers being connected 'with' the lower drum of the boiler unit by downcomers 18and the upper headers being connected with the upper drum of theboiler unit b v upcomers 19.- Thus it will be seen that the circulation in sets of tubes 11, 4, 12, 3. 3 and the front row of tubes of the bank 6 is in an upward direction. Inasmuch as there are a greater number of the tubes -4 than of the tubes 11 an adequate supply of water for the header 14. may be secured by providing downcomers 14a which supplement the tubes 11.

Suitable sheathingr is A'provided to enclose the front. top and side water walls. and an ash hopper 20 is providedbelow the comabustion chamber for the gravitating refuse which may be removed through the valve controlled opening 21.

Pulverized fuel with carrying air is introduced into the combustion chamber at the lower part thereof by means of nozzles 22 located at each corner ofthe chamber, which nozzles, as will be clear from Fig. 3, are set so as to deliver the fuel tangentiallyto a circle having its center in the axial line of the chamber whereby a whirl or vortex is set up, the axis of which is substantially vertical. .Air under pressure is admitted around the entering fuel through the openings 23` around the nozzles, which air is supplied from `the air heater 24 through the medium of the 'duct 25. Air, in addition to that admitted with the fuel and around the nozzles may be introduced into the combustion chamber through. a plurality of air pipes 26 located in ofthe same deLIee of fineness and in a steam generator of this type which is fired from' above, instead of below as herein shown, the heavier particles may pass out of the combustion` space proper without being consumed. In installations fired from above the downdraft and gravity cooperate to reduce the length of timesuch heavier particles remain in the combustion space. By firing from below as herein set forth the updr'aft" counteracts gravitv and the heavier particles are drawn relatively slowly upward thru the combustion space and this coupled with the whirling or vortical motion of the fuel and flame stream' affords ample opportunity for 1 complete combustion .of vthe lheavier particles. Ordinarily no appreciable Aloss will be encountered bv unconsumed fuel. entering the ash pit. but if operating conditions are such where this might result. the inlets 28 are em ploved as above pointed out. The introduction of the coal stream in the manner above described secures mixture of the coal and combustion air in the combustionsnace and an intensely hot flame results.-

. The temperature head of the furnace is fur#V ther increased by the prebeatiug of the combustion air. Thus there is a verv hifrh rate of heat transfer with. correspondingly great l capacity. IAs the fuel and flame stream and gases move upwardly the velocity diminishes so that the exit gases travel at a velocitvsuch as to secure effective heat transfer -in the bank of tubes 6,'the majorvportion of which constitutes what may' be termedan eco-nomizer section integral with the boiler. This economizer section reduces the temperature ofthe relatively hot gases entering the bank to a point where the air preheater is not subjected to an excessive temperature. The air preheater absorbs heatvand further reduces the temperature to a point where the finalexit temperatures are within allowable limits. l

Thus the coal is effectively burned and the I B. t. us. effectively liberated and effectively applied. 'Maximum efficiency with mairimumcapacity from a small installation are thus ensured. v

l. In a pulverized fuel burning setting, the i combination of a furnace-shaped boiler having its walls defined by upright steam evaporating' boiler tubes, downcomer means supplying the lower ends of the tubes, an outlet in the upper part of the boiler for the gaseous products of combustion, and means for introducingpulverized fuel into the.Y lower partof the combustion space including burnners substantially at the corners arranged tp tangentially deliver the fuel' into the combustion space to produce a vortical flame, the axis of which is perpendicular whereby the most intense combustion is opposite the lower end portion of the tubes where the mixturein the tubes lis most dense and whereby said portions of the tubes .are subject to both radiant4 heat and heat of convection.

2. In a pulverized fuel burner setting, the combination of a furnace-shaped boiler having its walls defined by upright steam evaporating boiler tubes. downcomer means supplying the lower ends of the tubes.l an outlet in the upper part of the boiler for the gaseous products of combustion, and means for introducing pulverized fuel into the lower part of the combustion space fincludingburners substantially at the corners arranged to tangentially deliver the fuel into the combustion ,space to produce a vortical flame the axis of which is perpendicular whereby the most intense combustion is opposite the lower end portion of the tubes where the mixture in the tubes is most dense and whereby said por-y tions ofthe tubes' are vsubiect to both radiant heat and heat of convection, the tubes defining certain of the walls being finned. A.,

3. In a pulverized fuel burning setting. the combination of a furnace-shaped boiler hav- 'ino` its walls defined by upright steam evaporating boiler tubes. a bank of upright convection tubes grouped with the upright tubes of one of the walls. downcomer means supplying the lower ends of the tubes, an. outlet in the upper part of the boiler for the gaseous products of combustion, and means for introducingpulverized fuell into the lower part of the combustion space including burners substantially at the corners arranged to tangentially deliver the fuel into the combustion space to-produce a vortical flame the axis of which is perpendicular, whereby the most in.-

anse combustion is opposite theulower end `ortion of the tubes where the mixture in the ubes is most dense and whereby said porions of the tubes are subject to both radiant neat and heat of convection.

In testimony whereof I have hereunto igned my name.

WILFRED R. WOOD.

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