US1731428A - Boiler furnace - Google Patents

Description

Oct. l5, 1929.

E. LUNDGREN BOILER FURNACE Filed Dec. 8. 1925 2 Sheets-Sheet l oct. 15, 1929.

E. vLUNDGREN BOILER FURNACE Filed Deo. 8. 1925 2 Sheets-Sheet 2 INVENTo/e ,6, s Z By fw www@ A Trop/Wsw Patented ocr. 15, lezeA UNITED sT-A'rss PATENT lour-Fica EDWIN LUNDGREN, OF FREDERICK, MARYLAND, ASSIGNOR TO INTERNATIONAL COM.- BUSTION ENGINEERING CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF 'DELAWARE norman FURNACE Application mea neoember s, 1925. serial No. 73,991.

lThis invention relates to boiler-furnaces, and is especially useful where the fuel is burned in suspension, as, for example, pulverized coal. I employ the term boiler-furnace as indicating a boiler installation', the

furnace of which is primarily defined by the boiler itself, whereby the evaporating elements are subjected to radiant heat.

lit is one of the objects of my invention to l@ utilize the radiant heat, or the radiation, to a maximum extent, and to provide a boiler-furnace in which the Haine can be so burned as to secure approximately the theoretical maximum flame radiation.

Another object of the invention is to simplify the boiler in some of its features, and to provide an installation which, 1n its overall dimensions, both as to height and ground area, is very small, as compared to what 1s today required in standard practice for producing the same, or anywhere near the same,

. quantityof steam.

It is another object of the invention to rovide a boiler-furnace sov constructed an arranged that it is possible to locate a super- -heater so as to obtain any degree of superheat desired.

llt is still a further object of the invention to make' it possible to fire the'fuelwith low injection pressure, and low airv` pressure,

whereby the power requirements for operatio are materially reduced.

My invention also contemplates a construction by virtue of which practically standard units may be employed, in consequence ofv which it is possible to construct boiler-furnaces of various capacities, merely by increasing or decreasing the number of units employed.

A further object of the invention is to so burn the fuel that the boiler-furnace of my invent-ion can bev effectively used.

How the foregoing, together with s uch other objects as may hereinafter-appear, or are incident to my invention, arefobtained, is

illustrated in the preferredv form in the ac.

companying drawings, wherein- Fig. 1 is a vertical section through a b1ler` furnace embodying my improvements.

Fig. 2 is a section taken on the line 2-2 of Fig. 1, and

Fig. 3 is a section taken on the line 3 3 of Fig. 1. Y

Referring now to the drawings, the reference character A denotes the boiler combustion chamber considered as a whole.v This combustion chamber is largely formed by boiler tubes subject to radiant heat, and by certain refractory wall portions to be de-V scribed. The combustion space of the furnace at the sides is defined by :two Water walls, a, a, such Water walls consisting of a plurality of tubes 7 slightly inclined from the horizontal, and arranged in a vertical row. These tubes are provided on opposite sides with longitudinally extending fins 8, which fins are preferably welded to the tubes, and cooperate with the tubes to constitute, in effect, a practically continuous metallic wall. At the rear, the tubes of the side water walls are connected into the headers 9, 9, and at the front they are connected into the headers 10, 10. The headers10,'10, are connected into the drum 11 by upcomers 12, 12. The headers 9, 9, are connected by downcomers 13, 13, to the drum 11, whereby circulation takes place downwardly through said downcomers into the headers 9, 9; thence through the tubes 7 to the headers 10, 10, and through the connections 12, 12, back tojthe drum. The interior of the combustion chamber is divided into vertical compartments b, c, d, e, by the water wallsf. Each of these water walls comprises tubes 7"L inclined slightly nected by rdoyvvncomcrs 18 with the drum 11,

and'the .headers 17 are connected by upcomers 19 to the drum 11.

A hollow wall portion 20 de ends from the arch 14 to the lower end o the water walls" f, this bafiie being divided to permit burners 2G, of which there is one llocated I above each vertical compartment described.-

of the passage'therethrough of the water walls Refractory walls form the ash pit, and surround the combustion space bridging the gaps'betwmni the various headers described. ln fact, these headers are set into these rel'rarlory walls, as will be clear on inspection of the drawings.

Located above the ash pit 15, and well beneath the lower end of the baille 20, and the lower ends of the water walls f, is a water screen f7 which is composed of tubes 21, so spaced apart that the gravitating refuse particles can. freely pass therebetween into the ash pit. At their rear ends the tubes 21 connect into the 'header 22, and at their front ends they connect into the header 23. The header 22 is supplied with water from the headers 1G by means ofthe connections 24, and the connections 25 constitute upcomers from the header 23 into the headers 17. Thus, the water screen is in substantially the same circulation `as water walls ly the arrangement of parts described, the interior of the combustion chamber is divided into the vertical compartments b, c, d, c, by the water walls f. The space is divided into a sort of aU-shape by the baille wall 20.

The pulverized lfuel is admitted into the top of the combustion chamberby means of These. burners are flattened so as to deliver a 5 thin sheet of fuel mixed with carrying air,

that is to say, mixed with only a portion` of the Vair required for combustion@ 'There is,

. thus, a fuel and flame stream for each vertical compartment, the fuel= and flame stream proceeding downw rdly in. advance of the wall 2() around thea lower end thereof, and between such lower end and the water screen (7, and thence up through the vertical com-- radiant heat thus obtained, and, therefore, transmit 1t at a maximum rate. Consequently, I can produce a given quantity of steam, with but a fraction of the evaporating area now required'for this purpose, and can develop this capacity enormously.

By virtue of the rapid absorption of heat by the tubes, there will be a tendency to unduly. lower flame temperature, to overcome which the balance of the air required for combustion is delivered in highly preheated form', so as to increase the temperature head. I accomplish this by providing a casing 28 over the front wall of the combustion chamber, and

`a casing 29 in back of the baille 20. Air is supplied to these casmgs from an air heater 30 located in the olf-take 27. Air enters into the combustion space from the casings 28 and 29 through the inlets 8l and 32. There are two rows of these inlets 31 in the front wal] )for each vertical compartment, and there are two rows of these inlets 32 through the baille 20 for each vertical compartment. The

fair admitted through these inlets preferably,

' of the baille 20 to the off-take, and I locate superheater elements 33 in the compartments to the rear of the baille 20 at about .the level of the lower end of the baille, and I locate econoniizer elements 34, if desired, in the top portion of the space behind the baille wall 20. It will be seen that the super-heater elements may be located at any level with convenience, and that, in consequence thereof, any desired degree of superheat may be obtalned.

I prefer that the total evaporating surface should bcsuch that the gases leave the economizer at a much higher temperature than heretofore contemplated in standard practice,

Vto the end that'the high degree of heat de sired for the combustion air may be absorbed in the air heater. Obviously, the casing 29, being subjectedto the heat of the waste gases,

will servev to impart additional heat to the air.

The function of the screen is to prevent slagging of the refuse particles, the screen aeting to cool such refuse particles while they are in transit to the point of deposit in the ash pit to a condition in 'which the particles are no longer molten, in consequence of which they remain. in individual form readily removable.

No slagging difficulties will be encountered elsewhere within the combustion chamber by virtue' of the action of the tubes.

It will be observed that the installation is essentially a down-draft one, in consequence of which. the injection pressure of the fuel and air may be relatively lower thanv would be otherwise required. This effects quite a saving in the `power requirements which would otherwise be considerably greater for reasons which will be fully appreciated by those skilledlin the art.

What' I claim is 1. In combination, a pulverized fuel burningcombustion chamber, and a plurality of walls dividing the interior into narrow flames KBO wa s boiler,1 tubes subject to radiant heat, said tubes bing spaced so that the fins substantially a ut.

2. ln combination, a pulverized fuel burning combustion chamber, and a plurality of walls dividing the interior into narrow flameways, said walls being composed of boiler tubes extending substantially for the full height of the combustion chamber, together with a depending baiiie transverse to the said -walls and cooperating therewith to make the lameways of approximately U-shape, and heat absorbing elements in a vertical leg p0rtion of a lameway, Said means comprising serially arranged Superheater and economizer elements.

][n testimony whereof I have hereunto signed my name.

` EDWIN LUNDGREN.

said walls being composed of finned

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