US2333631A - Steam generator - Google Patents

Description

Nov. 9, 1943.

E. G. BAILEY AL,

STEAM GENERATOR Filed Aug. 2, 1940 5 Sheets-Sheet l www . INVENTORS Ervz'n GBai/ey "4 Dana H/VMay ATTORNEY.

Nov; 9, 1943. E. G. BAILEY ETAL STEAM GENERATOR Filed Au 2, 1940 5 Sheets-Sheet 2 INVENTORS Ervin GfBaileg 34 Dna H NM ayo ATTORNEY.

Nov; 9, 1943.

E. G. BAILEY ETAL 2,333,631

STEAM GENERATOR Filed Aug. 2, 1940 5 Shets-Sheet 5 00 0 00 OO O 0 O O0 0000 O0 0C 00C 00 INVENTORS fz'w'n G Bailey 2 BY Dana HN M ayo ATTORNEY.

/4 n Ill/46 I 71/! Nov; 9, 1943. E. G. BAILEY 515p,

STEAM GENERATOR Filed Aug. 2. 1940 INVENTORS Err/m G: Bailey Da a H/VMayo ATTORNEY.

Nov. 9, 1943- E. G. BAILEY ETAL 2,333,631

STEAM GENERATOR Filed Aug. 2, 1940 5 Sheets-Sheet 5 INVENTORS Erz m G Bai/eg 2'9 BY Dana HM M ago ATTORNEY.

Patented Nov. 9, 1943 STEAM GENERATOR Ervln G. Bailey, Easton,Pa., and Dana 11. N.

Mayo, Ridgewood, N. 1., assignors to The Babcock & Wilcox Company, Newark, N. J., a corporation of New Jersey Application August 2, 1940, Serial No. 349,950

Claims. '(Cl. 122-436) The present invention relates to the construction and operation of steam generating units, and more particularly to steam generating units of the integral furnace type in which a major portion of the steam generating surface is arranged in a vertically disposed tube bank alongside the furnace chamber. Steam generating units of this type are disclosed in U. S. Patents Nos. 1,999,982 and 2,109,278.

The general object of our invention is an improved construction of a steam generating unit of the character described. A more specific object is the provision of a steam generating unit of the character described which is particularly designed and especially useful for operation with a mechanical stoker. A further specific object is the provision of an improved construction and arrangement of a steam superheater in a steam generating unit of the character described.

The various features of novelty which characterize our invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which we have illustrated and described a preferred embodiment of the invention.

Of the drawings:

Fig. 1 is a sectional elevation taken on the line l-l of Fig. 3;

Fig. 2 is a longitudinal vertical section taken on the line 22 of Fig. 1;

Fig. 3 is a horizontal section taken on the line 3-3 of Fig. 1;

Fig. 4 is a longitudinal vertical section taken on the line 44 of Fig. 1; and

Fig. 5 is a transverse vertical section taken on the line 55 of Fig. 2.

In the drawings we have illustrated a steam generating unit of the integral furnace type constructed in accordance with the invention. As shown, the unit has a setting substantially rectangular in horizontal and vertical cross-section formed by a front wall l0, rear wall II and opposite side walls I2 and [3. The upper side of the unit is closed by an inclined roof [4 and the bottom by a foundation floor l5.

Alongside the side wall I3 is arranged a bank of substantially vertical water tubes 20 forming the major portion of the steam generating surface of the unit. The tubes 20 are connected at their upper and lower ends to horizontally arranged drums 2| and 22 respectively extending longitudinally of the tube bank, the drums andtubes being supported from the foundation of the unit. The space containing the tube bank is divided into inner and outer heating gas passes l6 and II respectively by a vertical tile baflle l8 extending longitudinally of that space between the drums from the rear wall II to a point short of the front wall III. A heating gas outlet l9 controlled by a damper 23 extends over the major portion of the rear end of the gas pass II, as indicated in Fig. 1. The steam generating tubes in each gas pass are arranged in two longitudinally spaced groups to permit the installation of a steam superheater in the space so formed in the gas pass l6 and to provide for the bodily removal of the superheater through the gas pass II as hereinafter described.

The innermost tube row of the tube bank is formed by tubes 20 of larger diameter than the tubes in the remaining portion of the bank. The tubes 2|] are provided substantially throughout their height, except as hereinafter described, with metallic studs along their outer sides to provide means for hoding a layer. of initially plastic refractory 24 in position thereon, the refractory being arranged to cover the face of these tubes exposed to the gas pass l6 and close the intertube spaces of the studded tube portions. The tubes 20 and refractory 24 thus define a fluid cooled vertical partition between the space occupied by the main tube bank and the remaining portion of the setting. With the described arrangement of the studs and refractory, a considerable portion of the surface of the tubes 20 will be exposed on the outer face of the partition.

The studded portions of the tubes in the tube row 20 forming the rear end of the partition do not extend substantially throughout the height of these tubes. The studs and refractory are omitted from the upper portion of these tubes to form a vertically elongated rectangular passage or opening 30 at the upper rear corner of the partition, as shown in Fig. 2. The bottom of the passage 30 terminates a substantial distance above the lower drum 22. The effective flow area of the passage 30 is increased by bending the tubes 20, which would otherwise extend directly thereacross, outwardly in progressively greater bends 2|! as shown in Figs 1 and 3, thus forming an inclined tube screen in front of the passage 30. The passage 30 serves as an outlet for the heating gases generated by the fuel burning provisions in the remaining portion of the setting.

The described construction. and arrangement of the steam generating parts and heating gas flow path is particularly designed for use with fuel burning means having a stationary or movable grate on which a fuel bed is maintained at a level a substantial distance below the passage 30. A mechanical stoker 35 of the single retort underfeed type is conventionally illustrated in the furnace chamber 36 which occupiesthe remaining space in the setting. The stoker is mounted on a pair of laterally spaced masonry walls 31 defining the sides of an air chamber 38 below the stoker to which air for combustion is delivered by an external forced draft fan (not shown) through a duct 38. Solid fuel from a hopper 39 is fed by a suitable feeding mechanism 40 into the stoker retort 4| from which it is forced upwardly and outwardly over the movable stoker grate sections 42. Dumping grates 43 are positioned along the sides of the stoker and permit the fuel residue to be dropped into ash pits 44 along the sides of the air chamber. The ash is removed through suitable clean-out doors 45 in the lower part of the front wall.

A masonry wall 46 forming the inner side of the inner ash pit 45 aids in supporting the tube row 20. Several rows of Bailey blocks 41 are mounted on the subjacent portions of the tubes 20 to provide a smooth water cooled side wall at this side of the stoker. The portions of the tubes 20= between the wall 46 and drum 22 are bare, permitting ash carried over into this gas pass to drop therebetween. A clean-out door 48 provides access to the space 49 below the bare tube portions.

The side wall I2 is provided with a row of water tubes 50 extending from a bottom header upwardly along the side wall and roof l4 to the upper drum 2|. The rear wall H is likewise provided with a row of water tubes 52 having their lower ends connected to a header 53 and their upper portions curved as shown in Fig. 1 and connected to the drum 2|. Some of the tubes 52 are bent forwardly out of the plane of their lower portions and connected to the drum 2| in a second circumferential row. The headers 5| and 53 receive their water supply from the drum 22.

In the normal operation of the construction described, solid fuel is burned on the stoker grates substantially throughout the length of the furnace chamber and the heating gases generated rise and flow towards the heating gas outlet 30, passing across the screen tubes 20 before entering the passage 30 and main tube bank space. This relative arrangement of the stoker and heating gas outlet 30, and particularly the location and size of the outlet above the rear portion of the fuel bed, promotes mixing of the gases flowing towards the relatively restricted outlet and insures a path of travel of the combustible volatiles and unburned carbon in the heating gases of suflicient length in the furnace chamber to have combustion substantially completed therein. The location of the passage 30 above the fuel bed also reduces the carryover of particles from the furnace chamber into the main tube bank space.

The heating gases leaving the furnace chamber through the passage 30 flow longitudinally of the tube bank first through the gas pass I6 and then through the gas pass I! to the gas exit I9. The portion of the gas pass is opposite the passage 30 has substantially all of the tubes 20 omitted therefrom to thereby form a gas equalizing space IS at the entrance to the gas pass I6. With this portion of the tube bank space empty, the entering gases are free to pass downwardly as well as longitudinally of the gas passes l6 and I1, so that the tubes 20 will be contacted by heating gases substantially throughout their lengths. Ash depositing in the space 56 between the drum 22 and side wall l3 can be removed through the door 51.

A steam superheater is located in an intermediate portion of the gas pass l6 between the groups of generating tubes and comprises two transverse rows of inverted U-shaped tubes extending between transverse bottom headers SI and 62, which extend horizontally through the baflle l8, gas pass l1, and side wall l3 to points externally of the setting. The space between the upper looped ends of the superheater tubes and the drum 2| is substantially closed by a baffle 63, while plates 64 extending between the bottom drum 22 and headers 6|, 62 close this space as well as support the superheater. Tile 65 close the space between the superheater headers. The portion of the baflle [8 in the tube bank space and the corresponding portion of the side wall l3 opposite the superheater unit are removable sections and the corresponding portion of the gas pass I! is left unobstructed so that the superheater tubes and headers may be withdrawn as a unit through the side wall 13 for tu-be renewals. The superheater receives a supply of saturated steam from the drum 2| from a downcomer pipe 66 arranged externally of the side wall l3 and having a flanged connection to the end of the superheater header Bl. This external arrangement of the superheater headers and steam supply and discharge connections facilitates the operation of removing the superheater from the unit.

While in accordance with the provisions of the statutes we have illustrate'cband described herein the best form of the invention now known to us, 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 the'claims, and that certain features of our invention may sometimes be used to advantage without a corresponding use of other features.

We claim:

1. A steam generator comprising means defining a setting including a bank of vertically disposed steam generating tubes along one side of said setting, a furnace chamber along the opposite side of said setting, a mechanical stoker in said furnace chamber, and a vertical partition separating the space containing said tube bank from said furnace chamber and having a heating gas passage of restricted gas flow area therein confined to a portion at one end thereof substantially above the fuel level of said stoker.,.

2. A steam generator comprising means defining a setting including a bank'of vertically disposed steam generating tubes along one side of said setting, a furnace chamber along the opposite side of said setting, a mechanical stoker in said furnace chamber opposite the lower end of said tube bank and extending substantially the full length of said furnace chamber, and a partition between the space containing said tube bank and said furnace chamber having a heating gas passage of restricted gas flow area ,therein confined to a portion at one end thereof substantially above the fuel level of said stoker.

3. A steam generator comprising 'means defining a setting including a bank of vertically disposed steam generating tubes along one side of said setting, a furnace chamber along the opposite side of said setting, a mechanical stoker in said furnace chamber, a partition between the space containing said tube bank and said furnace chamber having a heating gas passage therein confined to a portion at one end thereof substantially above the fuel level of said stoker, and means forming a gas equalization space in said tube bank space extending substantially the height of said tube bank space and opposite said partition passage.

4. A steam generator comprising means defining a setting including a bank of vertically disposed steam generating tubes along one side of said setting, a furnace chamber along the opposite side of said setting, a mechanical stoker in said furnace chamber, a partition between the space containing said tube bank and said furnace chamber having a heating gas passage therein confined to a portion at one end thereof substantially above the .fuel level of said stoker, and a row of steam generating tubes in said partition having upper portions opposite said partition passage bent into said furnace chamber to progressively greater distances.

5. A steam generator comprising means defining a setting including a bank of vertically disposted steam generating tubes along one side of said setting, a furnace chamber along the opposite side of said setting, a mechanical stoker in said furnace chamber, a partition between the space containing said tube bank and said furnace chamber having a heating gas passage of restricted gas flow area therein confined to a portion substantially above the fuel level of said stoker and occupying only a small portion of the length of said partition, a row of steam generating tubes in said partition having upper portions opposite said partition passage bent into said furnace chamber to screen said partition passage, and a gas equalization space in said tube bank space opposite said partition passage.

6. A steam generator comprising means defining a setting including a bank of vertically disposed steam generating tubes along one side of said setting, a furnace chamber along the opposite side of said setting, a mechanical stoker in said furnace chamber opposite the lower end of said tube bank and extending substantially the full length of said furnace chamber, a partition between the space containing said tube bank and said furnace chamber having a heating gas passage therein conflned to a portion at one end thereof substantially above the fuel level of said stoker, a row of steam generating tubes in said partition having upper, portions opposite said partition passage bent into said furnace chamber to progressively greater distances, and a gas equalization space in said tube bank space extending substantially the height of said tube bank space and opposite said partition passage.

7. A steam generator comprising means defining a setting including a bank of vertically disposed steam generating tubes along one side of said setting. a furnace chamber along the opposite side of said setting, a partition separating the space containing said tube bank from said furnace chamber except at one end thereof, and a steam superheater extending transversely of said tube bank space comprising a pair of transversely extending headers in said tube bank space and a group of inverted U-shaped tubes connecting said headers, said superheater tubes and headers being mounted for removal as a unit transversely of said tube bank space through one side of said setting.

8. A steam generator comprising means defining a setting including a bank of vertically disposed steam generating tubes along one side of said setting, upper and lower drums connected to said tube bank, a furnace chamber along the opposite side of said setting, a partition separating the space containing said tube bank from said furnace chamber except at one end thereof, and a steam superheater extending transversely of said tube bank space comprising a pair of transversely extending headers in said tube bank space above said lower drum and a group of inverted U-shaped tubes connecting said headers, said superheater tubes and headers being mounted for removal as a unit transversely of said tube bank space through one side of said setting.

9. A steam generator comprising means defining a setting including a bank of vertically disposed steam generating tubes along one side of said setting, upper and lower drums connected to said tube bank, a furnace chamber along the opposite side of said setting, a partition separating the space containing said tube bank from said furnace chamber except at one end thereof, a steam superheater extending transversely of said tube bank space comprising a pair of transversely extending headers in the lower part of said tube bank space and a group of inverted U-shaped tubes connecting said headers, means for removably mounting said headers on said lower drum, and a steam pipe connecting said upper drum to one of said superheater headers externally of said setting.

10. A steam generator comprising means defining a setting including a bank of vertically disposed steam generating tubes along one side of said setting, upper and lower drums connected to said tube bank, a furnace chamber along the opposite side of said setting, a partition separating the space containing said tube bank from said furnace chamber except at one end thereof, a steam superheater extending transversely of said tube bank space comprising a pair of transversely extending headers in the lower part of said tube bank space and a group of inverted U-shaped tubes connecting said headers, said superheater tubes and headers being mounted for removal as a. unit transversely of said tube bank space through one side of said setting, and a steam pipe connecting-said upper drum to one of said superheater headers externally of said setting.

ERVIN G. BAILEY. DANA H. N. MAYO.

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