US2332534A - Steam generator - Google Patents

Description

Oct. 26, 1943. E. J. RooN'EY 2,332,534

STEAM GENERATOR I Fild Sept. 7, 1938 4 Sheets-Sheet 1 f INVENTOR.

f ATTORNEY.

STEAM GENERATOR INVENT OR.

Edu/ard Jfooncy ATTORNEY.

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E. J. ROONEY STEAM GENERATOR Filed Sept. 7, 1938 OOO Oct. 26, 1943.

INVET-OR Edu/ard JRooney ATTORNEY.

oct. 26, 1943.

E. J. ROONEY STEAM GENERATOR Filed Sept. 7, 1938 4 Sheets-Sheet '4 O o o i o U c n o 000% j IQOOO 35 g ae/ Y o 6 "T3 o l Y Ao o o o .OO q OO :l

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Patented oct. 2s, 1943 STEAM GENERATOR Edward J. Rooney, Bayonne, N. J., assignor to The Babcock & Wilcox Company, Newark. N. J., a corporation of New Jersey Application September 7, 1938, Serial No. 228,734

' 7 Claims. (Cl. 122-473) The present invention relates to the construction and operation of vapor generating units, and more particularly, to water tube steam boilers particularly designed for and especially useful in marine ins.tallations.`

Steam generating installations in the marine field are characterized by relatively low space,

weight, and headroom limitations, all contributing towards the use of compact light-weight steam generator designs of adequately high eiliciency requiring a minimum alteration of the surrounding ship structure. The recent trend in this eld towards units adapted to produce steam at A relatively high pressures and high superheat temperatures with control of the superheat temperature over a wide range has substantially increased the problems of design and construction.

One proposed unit for this service has a separately red auxiliary furnace chamber incorporated in the generator setting and arranged to regulably heat the steam superheating surface. To reduce the space requirements of the unit and to more effectively utilize the heating gases from the auxiliary'furnace, the setting has only a single gas outlet iiue for all of the heating gases from both the main and auxiliary furnace chambers.. The flow of products of combustion from the auxiliary furnace through the main furnace chamber however tends to substantially interfere with the progress of combustion in the main furnace chamber due to the consequent introduction of a substantial amount of relatively cold and v vinert gases therein. A further structural disad-` vantage of such units resides in the relatively small amount of steam superheating surface rcapable of being located therein in a position for effective heat absorption and the difficulties of adequately protecting and supporting such surface.- A further disadvantage resides in the location of the main and auxiliary furnace burner groups at substantially different elevations, necessitating operating platformsat different levels and increasing the work of operators.

The main object of my invention is the provision of an improved construction of a steam generating unit of the general type described which is particularly characterized by an arrangement and construction of the main pressure parts permitting the incorporation of a large area of adequately supported and protected steam superheating surface, a substantial combustion space in the main and auxiliary furnaces, a desirable fuel burner arrangement, a common gas outlet ue for the main and auxiliary furnaces the unit and desirable combustion conditions in the main and auxiliary furnace chambers. superheat control over a wide range of temperatures. and a high overall efficiency.

T he various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a partof this-specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had tothe accompanying drawings and descriptive matter in which I 'have illustrated and described a preferred vembodiment of my invention.

Of the drawings:

Fig. 1 is a partly diagrammatic sectional elevation of a steam generating unit constructed in accordance with my invention;

Fig. 2 is an enlarged vertical section taken on the line 2-2 of Fig. 1;

Fig. 3 is an enlarged `pian section taken on the line 3-3 of Fig. 1;

Fig. 4 is an enlarged view of a portion of Fig.

' 1, the superheater tubes being omitted; and

while retaining a relatively low draft loss through 53 Figi. 5 is a section taken on the line 5- 5 of Fig.

The steam generating unit illustrated comprises" a setting II) of substantially rectangular transversely elongated cross-section, a horizontally arranged steam and waterv drum II extending longitudinally thereof, a laterally offset lower water drum I2 arranged along one side thereof and connected to the drum I I by a relatively wide inclined bank of bent steam generating tubes I3.

The tube bank I3 extends the full length of the setting,` the end walls I4 and I5 of which are formed by refractory. At the outer side of the tube bank I3 is a vertical sidewall I6 which unites with the walls I4 and I5 and roof I1 to form a gas outlet flue I8 at the outer side of the tube bank. A bank of economizer or air heater tubes I9 can be advantageously located in the outlet flue I8. y

At the inner side of and below the tube bank I3 is located a main furnace chamber 20 adapted to be fired by a plurality of fluid fuel burners 2I arranged to discharge through burner ports 22 in the front wall I4. The main furnace chamber extends the full length of the setting, with the burners located so as to provide ample space for combustion and to avoid damaging flame impingement.

In accordance with my invention the remaining portion of the setting is utilized for the location ently fired auxiliary furnace chamber for regulably heating the superheating surface. As shown, a small diameter water drum or header is arranged below the level of the water drum I2 and at the opposite side of the main furnace chamber. The drum 25 is directly below and connected to the steam and water drum II by transversely spaced groups of vertically extending water tubes 26, 21, and 28. The tubes 26 are arranged adjacent the main combustion chamber with the upper middle parts of the innermost rows of tubes bent inwardly toward the same.

'I'he tubes 21 are of larger diameter than the tubes 26 or 28 and arranged in a single row. The tubes 21 act as columns aiding to support the steam and water drum II. The two front end tubes 21 are closely spaced and serve as supports for nested rows of horizontally arranged U-shaped superheater tubes 38 positioned between the tube groups 28 and 26 with their tube legs surrounding the tube row 21. The superheater tubes have their ends connected to a pair of external vertbcally arranged headers 3l and 3 2, the header 3| serving as an inlet and outlet header. As shown in Figs. 4 and 5, each of the superheater supporting tubes 21 carries a vertical series of heat resistant support castings along one side thereof, each consisting of a pair of semi-circular collars 34 fitting around the tube and a perforated plate 35 carried by the collars and through the openings in which the superheater tubes extend. Each of the support castings is held in position on the supporting tube by a semi-circular clamp 36 welded to each collar 34 and by a lug 31 welded on the tube. As shown in Fig. 5, the supporting tubes have their support castings arranged at opposite sides. 'Ihe superheater support structure is reinforced by welding together adjacent collars of the supporting tubes.

The rows of tubes 28 are arranged in staggered relation at the outer side of the superheater and serve as a water tube screen between the superheater tubes and an auxiliary furnace chamber 40 occupying the remaining portion of the setting. The auxiliary furnace chamber extends the full length of the setting with its sides defined by the tube rows 28, refractory bottom 23, a vertical outer side wall 24, and an inclined portion of the roof I1. The side wall 24 and inclined roof portion of the auxiliary furnace chamber are protected by a row of water tubes 4I extending along the same from a bottom header 42 to the steam and water drum II. The tubes in the forward half of the side wall and roof are of fully studded refractory covered construction, While the tubes in the remaining portion of the side wall and roof are of partly studded construction, thus providing a refractory-faced construction. in the forward portion of the auxiliary furnace and alternately cold surface and refractory in the rear portion. The auxiliary furnace chamber is fired by a plurality of vertically spaced uid fuel -burners 43 arranged to discharge through burner ports 44 in the front Wall I4. The burners 43 are located at substantially the same levels as the burners 2| for the main furnace chamber. This arrangement permits the use of a single operating platform along the front wall with greater convenience for operators in charge of the burners.

In the described construction only the auxiliary furnace side wall'24 and roof arefluid cooled, while the remaining walls of the setting are formed of refractory. The setting also includes an outer casing spaced from the refractory walls to provide a space through which combustion air is supplied to the fuel burner ports. The casing 50 also serves to enclose water supply connections from the drum I I to the several generating sections of the unit. Downcomers 5I at opposite ends of the unit serve the drum I2 and tube bank I3. Downcomers 52 connect the drum I I to the drum 25, while downcomers 53 connect the drum I I to the header 42.

With the setting construction described, the heating gases generated in the auxiliary furnace chamber ow laterally and transversely over the screen tubes 28, superheater, and superheater support tubes into the main furnace chamber, and then outwardly over the main tube bank and economizer tubes I8 through the gas outlet flue I8. Short curved baiiles 55 are formed at the upper and lower ends of one row of tubes 28 to limit bypassing of the superheater gases around the ends of the superheater. At the opposite side of the superheater and spaced from the superheater tubes is a partition or baille 56 extending upwardly from the drum 25. The space is Wider toward the top of the baille to facilitate gas ow across the superheater. The partition 56 is formed by metallic studs welded along the length of the innermost row of tubes 26 and refractory closing the intertube spaces of the studded portions of the tubes. The partition 55, like the side wall 24, has the refractory covering the inner face of the tubes throughout the forward portion of its length, while the remaining portion has refractory in the intertube spaces only. The partition terminates short of the bottom of the drum II, leaving a passage therebetween across which the unstudded portions of the partition tubes extend.

With the described construction the steam generating unit is started up with only main furnace chamber burners 2I in use. The heating gases generated by the fuel burning in suspension therein flow transversely of the tube bank I3 and the gas outlet flue I8 passing over the economizer tubes I9 before leaving the unit. The fluid-cooled partition 55 and tubes 26 form an effective radiant heat shield between the main 'furnace chamber and the superheater tubes 30.

When sucient steam is flowing through superheater tubes 30 the auxiliary furnace chamber burners 43 are started up and regulably operated as to number in use and firing rate to control the superheat temperature. The heating gases generated in the auxiliary furnace chamber flow substantially horizontally across the rows of screen tubes 28 and superheater tubes 3U throughout their length due to the gas flow equalization space formed by the arrangement of the partition 56 throughout its extent in spaced relation with the superheater tubes. This construction facilitates effective convection heating of the entire superheating surface. After leaving the superheater tubes these gases flow across the tubes 26 and over the upper end of the partition 55 through the extreme upper portion of the main furnace chamber 20. The confinement of the auxiliary furnace products of combustion to the extreme upper portion of the main furnace chamber avoids the introduction of relatively cold and inert gases into the main combustion zone of the main furnace chamber so that combustion is completed therein with little or no interference by the heating gases of the auxiliary furnace. The gases then pass across the upper end of the tube bank I3 to the gas outlet flue I8, within which they contact with the economizer t'ubes I9. The contact of these gases with the gases and without any substantial change f direction in the same whereby the pressure drop therethrough is extremely low. The described construction and` operation of the baille 58 effectively screens the radiant heat of the main furnace from the superheater. The Adescribed ar-v rangement of the auxiliary furnace chamber at substantially the same elevation as the main furnace chamber simplifies the supporting structure of the unit and permits the arrangement of the water tubes associated with the superheater in a position to function most effectively as supports for the steam and water drum I I. The arrangement of the auxiliary furnace -parts also simplies the installation, support and removal of the superheater tubes.

While in accordance with the provisions of the statutes I have illustrated and described herein the best form of the 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. The word outer is used herein to designate the side of the tube banks and associated parts opposite the side thereof facing the main furnace chamber.

I claim:

1. A steam generator comprising a setting, an upper steam and water drum, a laterally offset lower water drum, a bank of inclined steam gen-v erating tubes connecting said upper and lower drums, a second water drum arranged directly below said upper drum, a group of vertically Aarranged water' tubes connecting the upper drum to said secondwater drum, a main furnace chamber between said tube bank and said tube group, means for firing said main furnace chamber, a vertically arranged group of horizontally extending U-shaped superheater tubes at one side of and screened by -said tube group from said main furnace chamber, an auxiliary furnace chamber laterally adjoining the outer side of said superheater tubes, means for independently ring said auxiliary furnace chamber, a single heating gas outlet flue at the outer side of said tube bank and arranged to receive all of the heating gases owing from both of said furnace chambers, said ue being so located that the heating gases from said auxiliary furnace chamber tend to flow over said superheater tubes, through said main furnace chamber and across said tube bank before entering said flue, and a partition at the superheater side .of said main furnace chamber and arranged to direct the heating gas ow from said auxiliary furnace chamber across the upper part of said main furnace chamber and to shield'said super- Vheater tubes from flame radiation from said main furnace chamber.

2. A steam generatorcomprising a setting, an

upper steam and water drum, a laterally offset lower water drum, a-bank of inclined steam gendrums. a second water drum arranged directly below said upper drum, a group of vertically arrangeddrum-supporting water tubes connecting the upper drum to said second water drum, a main furnace chamber between said ltube bank and said tube group. means for firingVVV said main furnace chamber, a group of superheater tubes adjacent said tube group, an auxiliary furnace chamber laterally adjoining the outer side of said superheater tubes, means for independently firing said auxiliary furnace chamber, a single heating gas outlet ue at the outer side of said tube bank and arranged to receive all of the heating gases flowing from both of said furnace chambers, said vflue being so located that the heating gases from said auxiliary furnace chamber tend to flow over said superheater tubes, through ,said main furnace chamber and across said tube bank before entering said iue, and refractory means cooperating with tubes of said tube group to form a fluid-cooled partition at the superheater side of said 'main furnace chamber extending upber between said tube bank and said tube group,

means for firing said main furnace chamber, a

group of superheater tubes arranged adjacent sa'id tube group, an auxiliary furnace chamber laterally adjoining the outer side of said tube group, means for independently firing said auxiliary furnace chamber, a single heating gas outlet flue at the outer sidelof said tube bank and arranged to receive all of the heating gases flowing from both of said furnace chambers, said flue being so located that the heating gases from said auxiliary furnace chamber tend to flow oversaid tube group, through said main furnace chamber and across said tube bank before entering said flue, and a partition at the tube group side of said main furnace chamber and arranged in laterally spaced upwardly diverging relation to said superheatertubes to form a gas equalizing space therebetween through which heating gases from said auxiliary furnace chamber iiowing over said superheater tubes pass before contacting with said tube bank and a radiant heat shield between said superheater tubes and Vsaid main furnace chamber.

4. A steam generator comprising a setting, an upper steam and water drum, a laterally oifset lower water drum, a bank of inclined steam gen- .erating tubes connecting said upper and lower drums, a second water drum* arranged directly below said upper drum, a group of vertically arranged, water tubes connecting the upper` drum to saidl second water drum, a main furnace chamber between said tube bank and said tube group, means for firing said main furnace chamber, a group of superheater tubes positioned within said tube group, an auxiliary furnace chamber laterally adjoining the outer side of said superheater tubes. means for independently firing said auxiliary furnace chamber, the means for firing said erating tubes connecting said upper and lower main and auxiliary furnace chambers being arranged at substantially the same elevation, a single heating gas outlet flue at the outer side of said tube bank and arranged to receive all vof the heating gases flowing from both of said furnace chambers, said flue being so located that the heating gases from said auxiliary furnace chamber tend to flow over said superheater tubes, tube group, through said main furnace chamber and across saidtube bank before entering said flue, and a partition arranged to shield said superheater tubes from flame radiation from said main furnace chamber and to direct the heating gas flow from said auxiliary furnace chamber after contacting said superheater tubes across the upper part onlyr of said tube bank. f

5. A steam generator comprising a setting, an upper steam and water drum, a laterally offset lower water drum, a bank of inclined steam generating vtubes connecting said upper and lower drums, a second water drum arranged directly below said upper drum. a group of vertically arranged water tubes connecting the upper drum to said second water drum, a main furnace chamber between said tube bank and said tube group, a plurality of fluid fuel burners for firing said main furnace chamber, a vertically arranged group of horizontally extending U-shaped superheater tubes positioned within said tube group,

means for supporting said superheater tubes from tubes of said tube group, an auxiliary furnace chamber laterally adjoining the outer side of said superheater tubes, a plurality of fluid fuel burners for independently ring said auxiliary furnace chamber. the fluid fuel burners for firing said main and auxiliary furnace chambers being arranged at substantially the same elevation, a single heating gas outlet flue at the outer side of said tube bank and arranged to receive all of the heating gases flowing from both of said furnace chambers, said flue being so located that the heating gases from said auxiliary furnace chamber flow over said superheater tubes, tube group, through said main furnace chamber and across said tube bank before entering said flue, and means associated with the tubes of said tube group adjoining said main furnace chamber forming a partition shielding said superheater tubes from flame radiation from said main furnace chamber and directing the heating gases from said auxiliary furnace chamber towards the upper portion of said tube bank.

6. A steam generator comprising a setting, an upper steam and water drum, a laterally offset lower water drum, a bank of inclined steam generating tubes connecting said upper and lower drums, a second water drum arranged directly below said upper drum, a group of vertically arranged drum-supporting water tubes connecting the upper drum to said second water drum, a

main furnace chamber between said tube bank and said tube group, means for ring said main furnace chamber, a vertically arranged group of horizontally extending U-shaped superheater tubes screened by said tube group, m'eans for supporting said superheater tubes from tubes of said tube group, an auxiliary furnace chamber laterally adjoining the outer side of said superheater tubes, means for independently firing said auxiliary furnace chamber, a single heating gas outlet flue at the outer side of said tube bank and arranged to receive all of the heating gases flowing from both of said furnace chambers, said flue being so located that the heating gases from said auxiliary furnace charnbe1- flow over said superheater tubes, tube group, through said main furnace chamber and across said tube bank before entering said flue, and a fluid-cooled partition extending upwardly from said second drum towards and terminating short of said upper drum at the superheater side of said main furnace chamber and arranged to direct theheating gas flow from said auxiliary furnace chamber across the upper part of said main furnace chamber and to shield said superheater tubes from flame radiation from said main furnace chamber.

7. A marine steam generator comprising a setting, an upper steam and water drum, a laterally offset lower water drum, arbank of inclined steam generating tubes connecting said upper and lower drums and containing a major portion of the steam generating surface of the generator, a second water drum arranged directly below said upper drum, bottom supports for said water drums, a group of vertically arranged water tubes connecting the upper drum to said second water drumwith the tube connections to said upper drum conned to the portion thereof below the normal water level therein, some of the tubes within said tube group acting as supporting columns for said upper drum, downcomer tubes connecting the end portions 0f said upper drum and second water drum, a main furnace chamber between said tube bank and said tube group, means for firing said main furnace chamber, a group of horizontally arranged U-shaped superheater tubes positioned within said tube group, an auxiliary furnace chamber laterally adjoining the outer side of said superheater tubes, means for firing said auxiliary furnace chamber, and a single heating gas outlet ilue at the outer side of said tube bank and arranged to receive all of the heating gases flowing from both of said furnace chambers, said flue being so located that the heating gases from said auxiliary furnace chamber tend to flow over said superheater tubes, tube group, through said main furnace chamber and across said tube bank before entering said flue. EDWARD J. ROONEY.

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