US1784407A - Steam generator - Google Patents

Description

Dec. 9, 1930. y w R woon 1,784,407

STEAM GENERATOR 'Filed Aug.' 5. 1927 w I I J INVENTOR I ATTORNEYS' Patented Dec. 9, 1930 UNITED STATES PATENT OFFICE WILFRED It. WOOD, OF LONDON, ENGLAND, ASSIGNOR T0 INTERNATIONAL COMBUSTION ENGINEERING CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE STEAM GENERATOR f Application led August 5, 1927, Serial No.210,787, and in Great Britain' February 14, 1927.

This invention relate-s 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- 5 diant heat and very high capacities are obtainable with relatively small installations.

One of the primary objects of my invention is to introduce fuel` and air intosuch a furnace in an effective manner.

Another object of my invention is to ensure elfective circulation throughout such a boiler. K

A further object is to reduce the losses in combustibles in such an installation to a neg- Fig. 2 is a fragmentary section taken substantially on the lin'e 2-2 of Fig. 1, a portion of the view being broken out to condense the figure,

Fig. 3 is a fragmentary plan view of a detail of the invention, and

Fig. 4 is a diagrammatic plan View illustrating the manner of introducing fuel to the furnace.

seen that my improved steam generator comprises, in general, a combustion chamber A; a boiler unit B arranged at the rear of the combustion chamber and comprising an upper steam and water drum 4, a lower water drum 5, and a bank of upright tubes 6 connecting said drums; and burner means C to be hereinafter fully described.

The combustion chamber A comprises side tubular water walls 7 (only one of which appears in the drawings), a front tubular water wall 8, a rear tubular water wall 9 composed of the first row of tubes of the bank of tubes 6, a top or roof tubular water wall 10 and tubes 11 marginal of the bottom of the ligible quantity; and also to burn coarser fuel Referring now to the drawings, it will be.

combustion space. Suitable sheathing is provided for enclosingv the side, front and top water walls.

The side walls 7 comprise a plurality of closely spaced' upright tubes, preferably finned, connected at their upper ends into headers 12 and at their lower ends into headers 18. The upper headers 12 are preferably connected to the upper drum 4 of the boiler unit B by means of a plurality of bent tubes 14 andthe lower headers 13 mayl be directly connected into the lower drum 5 of the boiler unit as shown inl Fig. 1 at 13a. The front wall 8 comprises a plurality of similarly finned uprightv tubes, each tube of which is connected at its upper end into a separate header or junction box 15 and at its lower end into a separate header or junction box 16. Each of t-he upper headers 15 has connected thereinto a pair of tubes of the double row of tubes of which the roof wall 10 is composed, and these tubes are connected at their other ends into the upper steam and water drum 4. It is to be noted-that I have preferably provided the upper row of tubes of this double row with fins. Each of the lower headers 16 has connected thereinto a tube of the double row of tubes which constitute the tubes 11 marginal of the bottom of the combustion space. It will be seen that the headers 16 although closely spaced transversely considered, are spaced suiciently apart vertically considered as to provide ample space between the tubes 11 so that gravitating particles may pass therebetween to the refuse hoppers 17. The tubes 11 are connected at their ends opposite the headers 16 into the lower drum 5 of the boiler unit C.

From the foregoing it will be seen that .two upcomer tubes which connect into the upper steam and water drums of the boiler Yunit B. Thus effective circulation is ensured which is an important conslderation 1n boilers fired in the manner hereinafter appearing.

Pulverized fuel with carrying air is introduced into the combustion chamber A at the ,lower part thereof by means of the burners circle having its center in the axial line of the chamber ask diagrammatically indicated in Fig. 4. Air, in addition to that introduced at the burners with the fuel, is introduced into the combustion chamber by means of the air nozzles 18 located below the fuel burners, which air nozzles are arranged in like manner to the burners to tangentially deliver I their air streams. The air admitted through these burners is preheated as by means of an air heater 19 located in the flue 20, which air heater is provided with an air inlet 21 and an air outlet 22. The air may be caused to pass through the heater in any suitable manner as, for example, by the draught of the flue, or by means of a fan (not shown) or both. A duct 23, preferably branched and extending alongeach side of the combustion chamber, leads the preheated air from the air heater outlet to the nozzles 18.

From the foregoing it will be understood that the fuel streams injected by the burners C in the manner described will be given a violent swirling motion. The air injected by the nozzles 18 is likewise given a violent swirling motion. By so introducing the fuel and air a violently swirling vortical flame is produced, the axis of the vortex being vertical, which flame sweeps and scours the tubes of the water walls hereinbeforementioned and produces a high rate of heat transmission. By admitting the air injected by the nozzles 18 in the lower part'of the combustion chamber and below the point of fuel admission this air lifts the flame whereby heavier fuel can be burned than has heretofore been possible, the' air lift holding the heavier particles up and ensuring their complete combustion. .The firing of the fuel in the lower part of the furnace chamber puts gravity and the draft to some extent in opposition, in consequence of which the time interval for combustion of any given particle or particles is lengthened which not only makes it possible to burn coarser fuel but also secures complete combustion within the combustion space, reducing the loss of combustibles to a negligible quantity.

Admission of air below the burners, in addition to its sustaining feature, provides a body of air for the consumption of any of the fuel particles which tend to sink below the level of fuel introduction.

In order to maintain the aforesaid swirling action throughout the hei ht of the combustion chamber, I have provided additional air nozzles 24 in the upper part of the combustion chamber which are also arranged tangentially in like manner to the burners C. These nozzles lare preferably supplied with preheated combustion air under pressure.

Thus violent agitation, mixing and swirling of the fuel and flame stream is ensured in the upper portion of the combustion chamber.

The products of combustion leave the combustion chamber at the upper part thereof and pass over the tubes of the boiler unit B. In this connection it is pointed out that the front row of tubes of the boiler unit are backed by a baffle 25 extending from the lower 'drum 5 to a point short of the upper drum 4,

thus leaving sufficient space above the baiiie at.26 for the products of combustion to escape between the tubes of the front row 9. The products of combustion then pass over the bank of tubes 6 to the outlet 27 communicating with the liue 20. Although the temperature of the gases entering the bank of tubes is high, the final exit temperature is lowered by the bank of tubes, the superheater 28 which is located in the flue and by the air heater.

In order to ensure proper water delivery to the lower drum 5 of the boiler unit B, I have provided a baffle 29 for protecting the rear row of tubes of the bank of tubes 6 from the direct heat of the gases of combustion.

I claiinz- 1. A boiler furnace comprising upright being connected with more than one tube of.

the top wall, a lower water drum int which said bottom cross tubes are connected, an upper steam and water drum into which the tubes of the top water wall are connected, downiiow means connecting said drums and means for introducing pulverized fuel into said boiler furnace.

2. A boiler furnace comprising upright front, rear and side tubular water walls, a top water wall composed of a plurality of rows of water tubes, a plurality of rows of cross tubes at the bottom, each tube of said cross tubes being connected with a different tube of an upright wall, and each tubeof said upright wall being connected with a dierent plurality of tubes of lsaid top wall, a water drum into which sail bottom cross tubes are connected, a steam drum into which the tubes of the top water wall are connected, an off-take for the products of combustion and means for introducing fuel to be burned in suspension.

3. A boiler furnace including upright front, rear and side tubular water walls, a

- top tubular water wall comprising a double rcw of tubes, cross tubes at the bottom, 4a header connecting each tube of said cross tubes with a different tube of one of the said upright walls, and a header connecting eachv of the last mentioned tubes with a different pair of tubes of said top wall.

4. A boiler furnace including upright front, rear and side tubular'water walls, a top tubular water wall comprising a double row of tubes, a double row of cross tubes at the bottom, the tubes of one row being-staggered with relation to the tubes of the other row, a header connecting each tube of said `cross tubes with a different tube of one of v the said upright walls and a header .connectthata row of tubes of said banktog'ether kwith a bale associated therewith constitute a rear steam evaporating wallV of the combustion chamber subject to radiant heat substanT tially throughout its length, said 'baille terminating short of the top of the combustion chamber to provide an outlet for the gaseous products of combustion, other tubes of said bank being subject tothe heat of the gaseous products leaving saidoutlet and still other tubes of said bank bein shieldedfrom the heat of the gaseous proiucts of combustion, the aforesaid front, side, top and bottom tubes and the row of tubes constituting'the rear wall of the combustion chamber` being connected to -receive their water from the lower drum of the boiler unit.

6. In combination, a furnace-shaped boiler, meansfor introducin fuel tangentially into the lower inart thereo to vbe burnedin space, and means for introducing air for combustion below the point of fuelintroduction in n a manner to create an ascending vortical current sweeping the Walls of the furnace-shaped boiler.

7. In combination, a furnace-shaped boiler,

lmeans for introducing fuel tangentially into the lower part thereof to be burned in space, means for introducing air for'v combustion below the point of fuell introduction in a mannerA to createan ascending vortical current sweeping the walls of the furnace-shaped boiler, and means for introducing air above the point of fuel introduction to maintain said vertical current for the length of the fuel and flame stream.

8.V In combination, a furnace-shaped boiler, 'means for introducing fuel tangentially intou the lower. part thereof to be `burned in space, means for tangentially introducing air for combustion below the point of fuel introduction and means for tan entially introducing airabove the point of el introduction.

9. In combination, va furnace having an unrestricted combustion chamber formed of upright steam evaporating surfaces, means for introducing fuel tangentially into the lower part thereof to be burned in space, means for tangentially introducing air for combustion below the point of fuel introduction and means for tangentially introducing air above the oint of fuel introduction.

10. In comination, a furnace having an unrestricted combustion chamber vformed of upright steam evaporating surfaces, steam evaporating surfacesjextending across `the bottom, and steam evaporating surfaces extending across the top means for introducing fuel tangentially into the lower part of said combustion chamber; means for tangentially means for tangentially introducing air abovev the point of fuel introduction and below said steam evaporating surfaces.

In testimony whereof I have hereunto signed my name. l

' WIIJFRED WOOD.

alsr

Images