US2554631A - Steam generator - Google Patents

Description

y 1951 e. NEHRBAS 2,554,631

STEAM GENERATOR Filed Feb. 20, 1947 2 Sheets-Sheet 1 HOW/9RD G. NEHRBfl-S' IN YEN TOR.

43 40 43 a BY W W May 29, 1951 H. G. NEHRBAS STEAM GENERATOR Filed Feb. 20, 1947 xxx A v 2 Sheets-Sheet 2 Mbu l I I 30 3/ 32 33 Y Haw/m1: G. NEH/PEAS IN VEN ro/R By M W Patented May 29, 1951 UNITED I STATES OFFICE STEAM GENERATOR Howard G. Nehrbas, Hammond, Ind, assignor to Combustion Engincering-Superheater, Inc., a corporation of Delaware Application February 20, 1947, Serial No. 729,761

6 Claims.

The present invention relates to heat transfer apparatus and particularly to improvements in a forced circulation steam generator of high capacity.

The present invention contemplates the prothe ends of the inner wall of the furnace or vision of a steam generator of high capacity approximately in the plane marking the diviwhich is nevertheless of simple and compact sion between the furnace chamber I0 and the construction, adapting it for use in situations convection passage ll. As appears in Figure 3 where there is only a limited amount of space these headers are of inverted L-shape and the to accommodate such a generator as when ap ends I6, I? of the furnace coils l3, l4 and I5 plied to a Diesel unit for supplying steam to are connected to the vertically extending legs heat the cars of a train. A further feature of 28, 2| of these inverted L-shaped supply and the invention is a construction affording ready collecting headers. access to the steam generating elements for in- To provide an opening for the flow of gases specting them or replacing them if necessary. from the furnace Ill into the convection pas- The invention will be best understood upon sage H some of the tubes 23 of the lowermost consideration of, the following detailed descripradiant coil 13 are staggered or offset horizontion of an illustrative embodiment thereof tally with respect to the adjacent tube porwhen read in conjunction with the appended tions 2 3 so as to leave gas fiOW Op 5 drawing in which; between a number of adjacent tubes in the in- Figure 1 is a longitudinal sectional view of a ner wall of the furnace which otherwise is sursteam generator constructed in accordance with famed w th 0 3 Co tactin tube portions the present invention; which in the embodiment shown are disposed Figure 2 is a transverse sectional view of the in sup p d relation- Fillel plates 26 4 generator on the line 2-2 in Figure 1; and 5) ar pr v d to p v n gas leakage Figure 3 is a sectional elevation on the line through the Side Wa ls Of the furnace Where 33 in Figure 2. spaces are created between adjacent tube por- Figure 4 is a fragmentary plan View on a tions by the offsetting of the tube portions 23 enlarged scale of one of the furnace coils; from the adjacent tubes OthBI' filler plates Figure 5 is a side view on a still further en- 30 2? r p v between contiguous u p rlarged scale of part of the coil shown in Figtions of adjacent coils, as between coil is and ure 4. coil M, where the lateral extension of the end In its general aspects the steam generator emportions !5, I! thereof would otherwise leave bodying the present invention hasa U-shaped a p due to partial p on Of the Congas passage, one leg of which forms a furnace tinuity of the helical formed wall surface.

19 downwardly fired by fuel burner means 9 In the convection pass I! the steam generatand communicating through its inner side wall 111g surface is formed by ur Ve t p d at the lower end thereof with the juxtapos'i- 00115 30, 3 e having u t p dtioned convection passage H f m the p r like layers with their ultimate inlet and outlet end of hi h th spent gases pass t a Stack portions 34 and 35 connected to the horizontally :2, The walls of the f rnace ch ber is are disposed sections 22, 2% of the inverted L-shaped lined with radiantly heated steam generating supply and collecting headers. Each convection surfaces comprising (as shown) three superposed 0011 -3 Comprises Sevfiral Ser es connected helically wound tube coils !3, it and :5. Each grid-like t coils in n e p f a numof these cells is made up of a long length of ber of parallel tubes connected by return bends small diameter tubing which is helically wound at their contiguous ends n rr d in rows to form a coil whose successive convolutions are tending across the ga p d located in in contact to entirely line the side walls of the a vertical pl e h row f rm n a fl r furnace chamber, although the tube convolu- Several of which (three for p being 011- tions might be spaced apart and the intervals 50. nected in series to form a complete convection closed by fins or otherwise. The coils however coil which has its ultimate end portions 34 and are not fully circular but of a roughly square 35 connected to the shorter horizontal legs 22, shape (Fig. 2) and the inlet and outlet por- 28 of the inverted L-ohaped S pp d ollecttions l6, ii thereof are located at opposite coring headers respectively. The major part of more of the inner wall. These inlet and outlet each coil 30-33 is located centrally in the convection pass I i inasmuch as the parallel tube portions of the two central coils SI, 32 have their contiguous end portions interconnected by closely coupled integral return bends 46 while those tube portions 36, 3! which run vertically along the end i of the convection passage and the opposite side 62 thereof forming the boundary between the convection passage and the adjacent furnace chamber are connected to the contiguous tube portions by return bends or loops of wide radius. A similar coupling arrangement is followed for the inwardly positinned grids of the coils 3i and 33. Thus the greater number of parallel tubes of each coil are closely spaced in the center of the convection passage while the wider spacings of the tube portions 35 and 3? from the tube portions it, il leave spaces for gas flow along the coils in a vertical direction in the convection passage as the gases are directed back and forth cross the convection coils by the deflecting bafiies at which extend part of the way across the convection passage from the end wall ll and the inner wall ti! thereof. The outermost grid portions of the two convection coils 39 and 33 being located adjacent the side walls of the convection passage have tubes 59 thereof uniformly spaced and provided. with fins to close the spaces therebetween and close in the side walls of the convection passage.

The circulating pump 52 for the steam generator is supplied with water from a separator drum 53 through a do-wtocomer Fi l and discharges into the lower end of the vertically disposed portion 29 of the inverted Lshaped supply header. From this vertical portion 2% of the supply header the water enters the end portions it of the three radiantly heated coils l3, i i, iii and flows in parallel therethro-ugh, passing downwardly through the helical convolutions of each coil to be discharged from the lower ends of the three coils into the vertically disposed portion 2i of the collecting header from which the mixture of steam and water flows upwardly and through the horizontal portion 23 of the collecting header into the and water separating drum 53. Simultaneously with the supply of water to the radiant coils iii-45 the water passing upwardly through the vertically disposed portion 20 of the supply header enters the horizontally disposed portion 22 thereof and from the latter passes through the inlet portions 34 into each convection coil 3al33 and in parallel through the latter. Having flowed downwardly and upwardly a plurality of times through the parallel tube portions of each convection coil in the several parallel grid-like sections thereof the steam and water mixture is finally discharged through the end portion 35 at the top of each coil into the horizontal part 28 of the collecting header and mixing with the steam from the radiant coils l3-i5 passes into the separating drum 53.

Diametrically located on opposite sides of the vertical portions 2% and 2! of the supply and collecting headers, respectively, are mounting strips or brackets 55 to which are attached flangepcrtion E5 on the inner edges of the sides 59 of U-shaped casing sections 57, 58 for eniosing the generator.

In the event that it should become necessary to replace any part of the radiantly heated tubes in the furnace, access may be readily had to the latter by unbolting the two side flanges 58 and casing section 58 from the header carriedmounting strips and then withdrawing the entire casing section and insulation to afford direct access to the convection coils 13 to l5. If necessary, any one of these may be readily removed by simply cutting it off between the joints between its end portions [6 and I! and the nipples attached to the vertical portions 20, 2! of the supply and collecting headers. Likewise, access may be had to the convection section by first removing the bolts from the flanges which connect with the vertically disposed parts of the supply and ,collecting headers and then drawing the section 51 and its insulation away from the generator so that the convection coils are exposed.

The entire radiant section including the coils 13, I4, l5 connected to the vertical legs 20 of the headers may be removed as a unit (coils and vertical headers together with or without casing section 58 attached) upon unbolting the flanges between the vertical and horizontal header sections and also unbolting the section 57 for the convection section from the mounting strips on the headers 20, 2:. Likewise the convection section may be withdrawn as a unit ( coils 30, 3|, 32 and headers 22, 28) upon unbolting the flanges 60 and also unfastening the radiant casing 58 from the headers 20, 2!.

From the above it will be seen that the inverted L-shaped headers act as a structural support. To render this more rigid the horizontal header sections may be fastened together as indicated at 6| in Fig. 1.

Although an illustrative embodiment of the invention has been described in detail herein there are many changes and variations that may be made without departing from the spirit of the invention and, therefore, it is desired and intended to include all such changes and variations within the scope of the appended claims.

What I claim is:

1. Heat exchange apparatus having a furnace chamber and a juxtapositioned convection passage connected at contiguous ends for series flow of the products of combustion from fuel burned in the furnace; a water supply and a steam collecting header each of L-shape disposed respectively at opposite sides of the generator approximately in the plane dividing the furnace chamber and convection passage; helically wound tube coils stacked vertically in the furnace chamber with their end portions projecting from the furnace at opposite ends of the wall that is common to it and said convection passage for connection to the longer legs of said supply and collecting headers; and other steam generating coils having opposite ends thereof connected to the shorter horizontal legs of said supply and collecting headers and mounted in said convection passage.

2. Heat exchange apparatus having a furnace chamber and a juxtapositioned convection passage connected at contiguous ends for series flow of the products of combustion from fuel burned in the furnace; a water supply and a steam collecting header each of L-shape disposed respectively at opposite sides of the generator approximately in the plane dividing the furnace chamber and convection passage; and helically wound tube coils stacked vertically in the furnace chamber with their end portions projecting from the furnace at opposite ends of the wall that is common to it and said convection passage for connection to the longer legs of said supply and collecting headers; other steam generating coils having opposite ends thereof connected to the shorter horizontal legs of said supply and collecting headers and depending vertically therefrom into said convection passage and vertically spaced baffles extending from the wall separating the furnace chamber and convection passage and from the opposite Wall of the latter part of the way across said convection coils for directing heating gases across the latter in a plurality of passes.

3. In a steam generator having a furnace chamber anda juxtapositioned convection pass connected at contiguous ends to form a U-shaped passage for series flow of the products of combustion from fuel burned in the furnace; a water supply and a steam collecting header each of L-shape disposed respectively at opposite sides of the generator substantially midway of the side Walls thereof; radiantly heated heat transfer tubes lining the furnace walls with their end portions projecting from the furnace at opposite ends of the wall that is common to it and said convection pass for connection to the longer legs of said supply and collecting headers; and other steam generating tubes disposed in said convection pass with coils at opposite ends thereof connected to the shorter legs of said supply and collecting headers.

4. In a forced circulation steam generator having a furnace chamber and a juxtapositioned convection pass connected at contiguous ends to form an upright U-shaped passage into one end of which fuel is introduced and from the other end of which products of combustion are taken off; a water supply and a steam collecting header each of inverted L-shape disposed respectively at opposite sides of the generator substantially midway of the side walls thereof in the plane dividing the furnace chamber and convection passage; helically wound tube coils stacked vertically in the furnace chamber and having their end portions projecting from the furnace at opposite ends of the wall that is common to it and said convection pass for connection to the longer vertical legs of said supply and collecting headers; and other steam generating coils spaced transversely of said convection pass with opposite terminal ends thereof connected to the shorter horizontal legs of said supply and collecting headers and depending vertically therefrom into said convection pass.

5. In a forced circulation steam generator having a furnace chamber and a juxtapositioned convection pass connected at contiguous ends to form an upright U-shaped passage into one end of which fuel is introduced and from the other end of which products of combustion are taken off; a water supply and a steam collecting header each of inverted L-shape disposed substantially with their longer vertical legs located at opposite sides of the generator substantially midway of the side walls thereof in the plane dividing the furnace chamber and convection passage and their shorter legs extending horizontally at the top of the generator; helically wound tube coils stacked vertically in the furnace chamber and having their end portions projecting from the furnace at opposite ends of the wall that is common to it and said convection pass for connection to the longer vertical legs of said supply and collecting headers; and other steam generating coils spaced transversely of said convection pass with opposite terminal ends thereof connected to the shorter horizontal legs of said supply and collecting headers and depending vertically therefrom into said convection pass.

6. Heat exchange apparatus having a furnace chamber and a juxtapositioned convection passage connected at contiguous ends for series flow of the products of combustion from fuel burned in the furnace; a water supply and a steam collecting header disposed respectively at opposite sides of the generator approximately in the plane dividing the furnace chamber and convection passage; and helically wound tube coils stacked vertically in the furnace with their end portions connected to said headers, the superposed convolutions of said coils being in contact to form a continuous lining for the major part of the furnace wall with a number of convolutions of the coil adjacent the said contiguous ends of the furnace and convection passage being staggered on the side of the furnace adjacent the convection passage to provide openings in the furnace wall for gas flow into said convection passage.

HOWARD G. NEHRBAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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