US1992954A - Steam boiler - Google Patents

Description

March 5, 1935. H. J. KERR 1,992,954

7 STEAM BOILER Original Filed Feb. 4, 1929 5 Sheets-Sheet 1 OOOOOOODOOOOGOOOOOO 00090000 000000000 INVENTOR Howard J 'h err AT ORNEY March 5, 1935. H. J. KERR 1,992,954

' 7 STEAM BOILER Original Filed Feb. 4, 1929 3 Sheets-Sheet 2 March 5, 1935.

Original Filed Feb. 4, 1929 H. J.-. KERR STEAM BOILER 3 Sheets-Sheet 3 INVENTOR Howard J Ker! A ORNEY Patented Mar. 5, 1935 7 992 954 UNITED STATES PATENT OFFICE STEAM BOILER HowardJ. Kerr, Westfield, N. J., assignor to The 1 Babcock & Wilcox Company, Bayonne, N. J.,

a corporation of New Jersey Original application February 4, 1929, Serial No. 337,295. Divided and this application October 7, 1932, Serial No. 636,648 j 7 Claims. (Cl. 122235) My present invention relates to a method of in the flue 12 and comprising an inlet header 16 and apparatus for generating steam at high adjacent the bottom of the flue, and an outlet pressures in large capacity steam generating header 17 adjacent the top of the flue connected units. by a series of return bend tubes 18. The inlet The general object of my invention is the proheader 16 is connected to a suitable feed pump 5 vision of an improved method of and apparatus (not shown) through a supply connection 19. A for. generating steam at high pressures and in pair of steam and water drums 20 is symmetriamounts substantially in excess of those usually cally arranged longitudinally of the boiler adjaattained in modern steam generating units with cent the longitudinal center line thereof,extendcorresponding rates of heat input. A more ing over both the combustion chamberlo and flue 10 specific object is the provision of a steam boiler 12. The drums 20 are separately supported by in which substantially all of the steam generastraps 21 from cross-beams 22. 1 tion is effected in steam generating elements In the present construction substantially all of absorbing heat by radiation from the combustion the steam isgenerated in heating surface 7 archamber. A further specific object is the pro ranged for the absorption of radiant heat from 15 vision of a steam boiler having a forced flow fluid the combustion chamber 10. This heating surheatingsectionand one or more natural circulaface includes a row of tubes 23 extending'along tion steam generating sections and direct conan inclined bottom section of the front wall of nections between the forced flow sections and one the boiler and having their upper and lower ends or more of the natural circulation sections to connected respectively to'headers 24 and '25. A 20 accelerate the fluid circulation in the natural row of tubes 26 extend npwardly along the front circulation section or sections so connected. wall of the combustion chamber to an upper The various features of novelty which charheader 27, which is connected to the steam spaces acterize my invention are pointed out with parof the drums 20 near the front end thereof by 25 ticularity in the claims annexed to and forming tubes 28. The tubes 23 and 26 are preferably 5 a part of this specification. For a better undercovered on their furnace sides with refractory standing of the invention, its operating advanmaterial 29. A natural circulation in' this furtages and specific objects attained by its use, nace' wall section is established by tubes 30 exreference should be had to the accompanying tending from the water spaces of thedrums 20 30 drawings and descriptive matter in which I have to the bottom header 25. Recirculation tubes 30 illustrated and described preferred embodiments 31, on the outside of the combustion chamber, of my invention. preferably connect the headers 27 and 25.

Of the drawings, Each side wall of the furnace is similarly pro- Fig. 1 is a sectional elevation of a steam boiler vided with a row of closely spaced tubes 32 lead- 35 constructed'in accordance with my invention; ing from a horizontally disposed beam header 5 Fig. 2 is a vertical section through the boiler, 33 upwardly to the upper end of the combustion the left half being taken on the line 2-2 and the chamber, and having inclined portions 32 lining I right half on the line 2A-2A of Fig. l; and the roof of the chamber, as shown in Fig. 2, and Fig. 3 is a sectional elevation of the steam boiler thence connected to the drums 20 above the water 40 shown in Fig. 1 with a modified furnace wall level therein. To equalize conditions in the W04 section. drums, some of the tubes 32 of each side wall are The apparatus embodying my invention illusadvantageously connected into the drum for the f trated in the drawings-includes a furnace comopposite side. The side wall tubes-32 are prefbustion chamber 10 into which fuel is introduced erably covered with refractory material 29in the I and burned by suitable fuel burning means, such same manner as the front-wall tubes. A pluas powdered coal burners 11 located in the front rality of tubes 34 connect the water space of each wall thereof. A vertical flue 12 is formed at the drum 20 to the header 33 on the same side of the rear of the combustion chamber'with its upper combustion chamber. The roofportions 32 of end communicating therewith through an outlet the tubes 32 may be supported from above by 5 13 in the upper rear portion of the combustion suitablesupports 35. 0 a

chamber. A stack connection 14 for waste gases The fourth or rear Wall of the combustion is provided at the lower portion of the flue 12 chamber, which in operation is usually subjected beyond soot and dust hoppers 15. I to more intense heating effects than the other The fluid heating surface of the boiler adwalls of the chamber, has its sloping bottom pervantageously includes an economizer positioned" tion provided with a row of tubes 36 similar in 55 formation to the tubes 23, and connected at their upper and lower ends, respectively, to headers 37 and 38. The header 37 is connected to a header 39 arranged in the roof of the combustion chamber alongside the tubes 32 by a plurality of rows of vertical tubes 40, preferably staggered to facilitate the passage of heating gases between their upper end portions which extend .across the chamber outlet 13. The tubes 40 forming the rearmost row of tubes 40, are protected for a major portionof their length from the heat of the combustion chamber by a refractory wall 40 and form downcomers for the front tube rows, as is indicated by the arrows in Fig. 1.

A rapid fluid circulation can be maintained through the rear wall tubes 36 and 40 by the connection of the header 38 to the economizer outlet header 17 through a series of tubes 41 and the connection of the upper header 39 to the steam spaces of the drums 20 by a row of refractory covered inclined tubes 42, a header 43, and tubes 44 having their upper ends spaced alongthe sides of the drums 20.

A superheater formed in two side-by-side sections is advantageously located at the'upper end of the flue 12 at the rear of the gas outlet 13,.each section comprising inlet and outlet headers 45 and 46, respectively, connected by a series of return bend tubes 47. The inlet and outlet headers of the adjacent sections are preferably horizontally aligned, each extending approximately half way across the setting, as shown in Fig. 2. Each supe-rheater section is connected to the corresponding drum 20 by tubes 48, having their ends uniformly spaced along the corresponding drum 20 and header 45. The upper portions of the tubes 40 advantageously shield the superheater tubes from the radiant heat of the combustion chamber. Each outlet header 46 is connected to a steam main in the usual manner.

With the steam boiler constructed as described, the feed water is delivered to the economizer which may be steaming or non-steaming as conditions may make desirable. The fluid leaving the economizer outlet header is discharged into the header 38, passing upwardly through the rear wall tubes 36 and'40 in which a portion of the water is evaporated. The steam and water mixture entering the header 39 passes through the tubes 42, header 43, and tubes 44, into the drums 20, while some of the water is returned to the header 37 through the tubes 40 providing a natural circulation generating section. The effective cross-sectional area of the tubes 42 and 44 is advantageously restricted to obtain steam of the desired dryness'entering the drums 20 and to avoid carrying a water level in this wall section of the boiler. The natural circulation in the bank of tubes 40 will be considerably accelerated by the connection of the economizer thereto instead of to the .drumsZO, as is the usual prac: tice. The front and side wall tubes form natural circulation steam generating sections to which water is supplied by the tubes 30 or 34 from the water space of the drums 20, and the mixtures of steam and water from these sections are discharged into the steam space of the steam and water drum or drums connected thereto.- The steamso generated and collecting in the drums 20, is superheated in the tubes 47 before delivery to the point of steam utilization.

' The required supply of heat for effecting the described steam generation is delivered to the combustion chamber by the fuel discharged through the burners 11 and burned in the combustion chamber. The products of combustion from the combustion chamber pass across the upper end portions of the tubes 40 and downwardly through the flue 12, contacting successively with the superheater and economizer before leaving through the gas outlet 14.

The modification illustrated in Fig. 3 differs from the construction shown in Figs. 1 and 2, by the replacement of the bank of tubes 40 by a single row of refractory covered tubes 50 extending between the headers 37 and 39.

While in accordance with the provisions of the statutes I have illustrated and described herein the best forms of my invention now known to me, those skilled in the art will understand that changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention covered by my claims, and that certain features of my invention may sometimes be used to advantage without a corresponding use of other features. r The subject matter disclosed and claimed here,- in is disclosed but not claimed in my copending application, Serial No. 337,295, filed Feb. 4, 1929, of which this application is a division.

I claim:

1. A steam boiler comprising walls forming a combustion chamber, fuel burner means in one wall of said chamber, staggered rows of vertical steam generating tubes adjacent the rear wall of C said chamber, a vertical heating gas flue at the rear of said chamber and opening to thejupper portion thereof behind said steam generating tubes, a steamgenerating drum, means connecting said steam generating tubes to said drum, an economizer positioned in said flue, means directly connecting the outlet end of said economizerto the group of steam generating tubes, and a superheater positioned in said fiue above said economizer and arranged to be shielded from the radiant heat of the combustion chamberiby said generating tubes. 1

-2. In a water tube steam boiler having a preponderance of its steam generated in furnace wall tubes subjected to radiant heat, a steam and water drum, a combustion chamber, separate natural circulation steam generating sections separately connected to thedrum and including tubes in the walls of the combustion chamber, means for burning fuel in the combustion chamber, a forced flow economizer having tubes subjected to the combustion gases after they leave said chamber, a single row of wall tubes subject to a once through fluid flow from the economizer and having direct connections to the drum separate from the drum connections of the wall tubes of said steam generating sections, and means directly connecting the outlet of the economizer to the inlets of the tubes of said single row of wall tubes for a series flow therethrough to the drum.

3. In a water tube steam boiler having substantially all of its steam generated in furnace wall tubes subjected to radiant heat, a steam and water drum, a plurality ofnatural circulation sections separately connected to the drum and including wall tubes located in separate furnace walls forming sides of a combustion chamber,

-means for burning fuel in the combustion cham- 4. In a water tube steam boiler having a preponderance of its steam generated in furnace Wall tubes subjected to radiant heat, a combustion chamber, a steam and water drum extending over the combustion chamber, separate natural circulation steam generating sections separately connected to the drum and including tubes in the walls of the combustion chamber,

means for burning fuel in the combustion chamber, a forced flow economizer having tubes subjected to the combustion gases after they leave said chamber, an economizer flue alongside the combustion chamber and beneath the drum, a single row of wall tubes subject to a once through fluid flow from the economizer and having direct connections to the drum separate from the drum connections of the wall tubes of said steam gen erating sections, and means directly connecting the outlet of the economizer to the inlets of the tubes of said single row of wall tubes, the upper portions of the tubes of said single row extending across the furnace gas entrance to the economizer flue.

5. In a water tube steam boiler having substantially all of its steam generated in furnace wall tubes subjected to radiant heat, a steam and water drum, a plurality of natural circulation sections having separate direct connections to the drum and including Wall tubes located in separate furnace walls forming sides of a combustion chamber positioned beneath the drum, means for burning fuel in the combustion chamber, a forced flow economizer including tubes subject to contact with the furnace gases after they leave the combustion chamber, an economizer flue alongside the combustion chamber and beneath the drum, a separate wall tube section including an inlet header directly connected to the outlet of the economizer so as to receive the flow therefrom and positioned at a lower part of the combustion chamber, an outlet header for said separate section beneath the drum, a plurality of rows of tubes directly connecting the inlet and outlet headers and subjected to different degrees of radiant heat from the burning fuel, and refractory material shielding the tubes of one of said plurality of rows, the tubes of at least one of said plurality of rows being positioned Within the combustion chamber so as to be envelopedby the combustion gases while all of the tubes of said rows extend across the furnace gas inlet to the economizer flue.

6. In a water tube steam boiler having a preponderance of its steam generated in furnace wall tubes subjected to radiant heat, a combustion chamber, a steam and water drum extending over the combustion chamber, separate natural circulation steam generating sections separately connected to thedrum and including tubes in the walls of the combustion chamber, means for burning fuel in the combustion chamber, a forcedflow economizer having tubes subjected to the combustion gases after they leave said chamber, an economizer flue alongside the combustion chamber and beneath the drum, a single row of wall tubes subject to a once through fluid flow from the economizer and having direct connections to the drum separate from the drum connectionsof the Wall tubes of said steam generating sections, means directly connecting the outlet of the economizer to the inlets of the tubes of said single row of wall tubes, the upper portions of the tubes of said single row extending across the furnace gas entrance to the economizer flue,

tubes forming a part of the roof of the furnace extending over the economizer flue and constituting parts of the direct drum connections for said single row of wall tubes, and a superheater beneath said roof tubes and positioned at the top of the economizer flue.

7. In a water tube steam boiler having substantially all of its steam generated in furnace wall tubes subjected to radiant heat, a steam and water drum, a plurality of natural circulation sections having separate direct connections to the drum and including wall tubes located in separate furnace walls forming sides of a combustion chamber positioned beneath the drum, means for burning fuel in the combustion chamber, a forced flow economizer including tubes subject to contact withthe furnace gases after they leave the combustion chamber, an economizer flue along- 'side the combustion chamber and beneath the drum, a separate wall tube section including an inlet header directly connected to the outlet of the economizer so as to receive the flow therefrom and positioned at a lower part of the combustion chamber, an outlet header for said separate section beneath the drum, a plurality of rows of tubes directly connecting the inlet'andoutlet headers and subjected to different degrees of radiant heat, from the burning fuel, refractory material shielding the tubes of one of said plurality of rows, the tubes of at least one of said plurality, of rows being positioned within the combustion chamber so as to be enveloped by the combustion gases while all of the tubes of said rows extend across the furnace gas inlet to the economizer flue, roof tubes positioned over the economizer flue and constituting parts of direct connections between the upper header and the drum, and a superheater positioned at the top of the economizer beneath said roof tubes and connected to the steam space of the drum.

HOWARD J. KERR.

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