US2114223A

US2114223A - Steam boiler

Info

Publication number: US2114223A
Application number: US121A
Authority: US
Inventors: David S Jacobus
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1935-01-02
Filing date: 1935-01-02
Publication date: 1938-04-12
Anticipated expiration: 1955-04-12

Description

April 12, 1938.

D. s. JACOBUS STEAM BOILER q' iled Jan. 2, 1955 INVENTOR David 5'. Jacobus' &;-R w

ATTORNEY Patented Apr-.12, 1938 PATENT OFFICE 2,114,223 STEAM BOILER David s. Jacobus, Montclair, N. J.,' assignor to The Babcock & Wilcox Company, Newark, N. J., ,a corporation of New Jersey Application January 2, 1935, Serial No. 121 5 Claims. (01. 122-302) My present invention relates in general to the construction and operation of high capacity steam generating units, and more particularly to generating units having one or more water tube steam boilers of the bent tube type including steam heating surface and steam and water separating provisions.

One object of my invention. is the provision in i a steam boiler of the type described of an improved arrangement of the steam take-elf drum at an elevation insuring adequate space for effectively washing and drying the steam generated while permitting a water level in the tube bank connected thereto sulllcient to protect the tube seats at high loads without tending to flood the remaining steam drum or drums on a sudden drop in load.

A further object is the provision in a superheater boiler of the type described of an improved arrangement of the boiler tubes adjacent the superheater facilitating the arrangement of the sup'erheater supply and outlet connections, and permitting the use of a low cost construction of the steam drum to which those boiler tubes are connected.

A further object is the provision in a boiler of the type described of substantially all of the steam generating surface concentrated in two main banks with a single pass flow of the heating gases across those tube banks and transversely of the boiler drums.

The various features of novelty which characterize my invention are pointed out with particularity inthe claims annexed to and forming a part of this specification.

vantages and specific objects attained by its use, reference should be had to the' accompanying drawing and descriptive matter in which I have illustrated and described a preferred embodiment of my invention.

Of the drawing:

Fig. l is. a partly diagrammatic sectional elevation illustrating one embodiment of my invention;

Fig. 2 is an enlarged sectional elevation of the rear steam drum shown in Fig. 1; and

Fig. 3 is a section on the line 3-4 of Fig. 1.

In the embodiment illustrated, l0 designates a furnace or combustion chamber, the walls of The water tube steam boiler illustrated in the For a better understanding of the invention, its operating addrawing is of the bent tube type and comprises front, middle and rear upper parallel steam drums l5, l6 and !1 respectively, and a mud drum l8 therebelow.,. The upper drums are connected to the'mud drum by front, middle and rear banks of tubes 20, 2| and 22 respectively. The tube rows in the front bank 20 are separated into two sections and the space therebetween provides an effective location for a superheater 25. The tubes 20 in the tube rows in front of the superheater are arranged in alignment transversely of the drums with the well known alternate wide and'narrow spacings of the tubes in each longitudinal row. The tubes 20 at the rear of the superheater are preferably uniformly spaced with alternate tubes in each row'having their upper ends bent in two directions, as shown in Figs. 1 and 3, to enter the drum 15 in circumferential alignment with an adjacent tube in the same longitudinal row. By

this arrangement lanes are provided at the upper ends of the two rows of tubes of substantially twice the width as the spaces between the regitudinally of the drum as the tube openings for the tubes 20. The consequent increase in drum ligament strength permits the use of a thinner wall in this segment of the drum. The drum I5 is therefore formed by a thin wall segment I5" extending throughout most of its circumference and a thick wall segment I 5' welded together.

The tubes in the middle bank 2| are preferably arranged in a staggered formation and spaced so that the total flow area through the tube rows of the middle bank will be less than through the tube rows of the front bank to increase the mass flow of heating gases through the middle bank. The middle drum I6 is connected to the front drum l5 above and below the normal water level in the middle drum by

circulators

26 and 21 respectively. As shown in Fig. 1, the capacity of the boiler is increased by providing for 'a single pass flow of heating gases from the furnace l0 across the front and middle banks of tubes. This arrangement substantially lowers the draft loss through the boiler, and affords a more uniform distribution of the heating gases over the heating surface.

In accordance with my invention the rear or steam take-off drum l1 is'positioned at a substantially higher elevation than the drums I5 and IS, with the bottom of the rear drum preferably at least as high as the maximum water level in the middle drum IS. The middle drum I6 is connected to the rear drum l1 solely by steam cit-- culators 28, the flow area of which is so proportioned that the maximum water level in the rear tube bank will be only sumcient to fill the tubes 22 and cover the tube seats thereof in the drum I! at high loads, and thus protect the tubes and tube seats from overheating. To further protect the rear drum, the boiler feed. water is delivered thereto as hereinafter described. The number of tubes in the rear bank 22 is substantially less than in the front and middle banks, and as shown, only one row of tubes 22 is provided to minimize the level fluctuations in the drums l and IS on sudden drops in the boiler load due to changes in water level in the tubes 22.

At the rear of the tube bank 22 is positioned an upfiow economizer 30 in a gas pass 3i formed by the adjacent walls of the boiler setting and a vertical baflle 32 at the rear side of the tubes 22. The

baflle 32 extends upwardly from adjacent the drum l8 and terminates short of the bottom of the drum I! to provide an exit passage thereabove for the heating gases and insure a downward flow of heating gases over the economizer 30. The heating gases after passing over the tubes of the economizer 30 and above a soot collecting hopper 33, pass out through a. gas exit 34.

The elevated position of the rear drum l1 provides an adequate space for washing and dry- I ing the steam generated in the boiler and provisions for this purpose are incorporated in the upper part of the drum H. A steam and water separator 40 consisting of a twin arrangement of inclined corrugated plate separator sections 4! extends longitudinally of the drum I! at opposite sides of the vertical axial plane thereof and between the discharge of the circulators 2B and one or more steam outlet pipes 43. The steam and water separator illustrated is similar to that disclosed in Patent No. 2,007,966, granted July 16, 1935. In the present arrangement the separator drain pipes 42 extend downwardly into corresponding tubes 22 to a level below the'minimum water level therein in operation, so that the drain pipes will be continuously water sealed. Steam washing nozzles are arranged in front of each separator section 4| along the length thereof to provide a sheet of feed water across the inlets of the separator sections. The nozzles 44 are mounted on the ends of tubes 45 connected to the tubes at the upper end of the economizer 30.

The'outlet pipes 43 from the rear drum I I extend to an external distributing header 50 connected to the inlet end of each superheater tube 25, the outlet end of which is connected to an adjacent outlet header 5|. The portions of each superheater tube passing downwardly from the headers 50 and 5| to the main multi-looped tube coil located between the sections of the front tube bank are arranged to pass through the lanes formed by the bent upper portions of the tubes 20. Any tendency for the heating gases to bypass through these lanes is thus offset by the arrangement of the superheater tubes therein.

In operation, the water level in the middle drum I6 is used as the basis of regulating the feed water supply to the boiler. With the water level therein indicated in Fig. 1, the water level in the front drumii at normal load will be slightly higher due to the lesser density of the fluid in the front tube bank. Under these conditions, the water level in the rear drum II will be only sufficient to cover the tube seats of the tubes 22 therein, as indicated in Figs. 1 and 2. The relatively small steam liberating space in the drums l5 and I6 is compensated-by the substantial amount of steam and water separating space in the rear drum H. The safety of the rear drum is further insured by the supplying of the boiler feed water to that drum. While the water level in the tubes 22 will fall at light loads, the degree of protection then required will be substantially less due to the lower temperature of the heating gases. The effect of the pressure drop through the twin separator on the separator drainage is offset by the sealing of the drain pipes in the tubes 22.

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.

I claim:

l. A water tube boiler comprising front and rear upper drums, a mud drum below said upper drums, vertically extending front and rear banks of tubes connecting said front and rear drums to said mud drum respectively, said rear drum being arranged relative to said front drum so that the bottom of said rear drum is substantially as high as the top of said front drum, circulator tubes arranged to connect said front and rear drums only above the normal water level in said front and rear drums, a steam outlet from said rear drum, a steam and water separator in said rear drum between said circulator connections thereto and said steam outlet therein drain pipes for said separator having their lower ends fluid sealed in the tubes of said rear bank, and means for delivering feed water for said boiler to said rear drum in washing relation to the steam delivered thereto from said front drum.

2. A water tube boiler comprising front, middle and rear upper drums, a mud drum below said upper drumsQvertically extending front, middle and rear banks of tubes connecting said front, middle and rear drums to said mud drum respectively, said rear drum being arranged relative to said middle and front drums so that the bot-i tom of said rear drum is substantially higher than the top of said middle drum, and said rear tube bank having a substantially lower number of rows of tubes transversely of said rear drum than the transverse tube rows in said middle and front banks, circulator tubes arranged to connect said front and middle drums above'and belo'wthe normal water level in said middle drum, circulator tubes arranged to connect said middle and rear drums only above the normal water level in said middle drum, a steam outlet from said rear drum, means for delivering feed water for said boiler to said rear drum, a furnace adjacent said front tube bank, and said drums and tube banks being constructed and arranged to provide a single flow of heating gases across said tube banks and transversely of said drums.

3. A water tube boiler comprising front, middle and rear upper drums, a mud drum below said upper drums, vertically extending front, middle and rear banks of tubes connecting said front, middleand rear drums to said mud drum respectively, said rear drum being arranged relative to said middle and front drums so that the bottom of said rear drum is substantially as high.

as the top of said middle drum, and said rear of rows of tubes transversely of said rear drumtube bank having a substantiallylower number than the tube rows in said middle and front banks, circulator tubes arranged toconnect said front and middle drums above and below the normal water level in said middle drum, clrculator tubes arranged to connect said middle and rear drums only above the normal water level in said middle drum, a steam outlet from said rear drum, a steam and water separator in said rear drum between said-circulator connections thereto and said steam outlet therein, a furnace adjacent said front tube bank, said drums and tube banks being constructed and arranged to provide a single flow of heating gases across said tube banks and transversely of said drums, and meansfor delivering feed water to said rear drum.

4. A water tube boiler comprising front and rear upper drums, a mud drum below said upper drums, vertically extending front and rear banks of tubes connecting said front and rear drums to said mud drum respectively, circulator tubes arranged to connect said front and rear drums, a bank of superheater tubes positioned between tubes of said front bank, at least some of the tubes in said front bank having their upper portions bent to entersaid front drum in substantially the same plane transversely of said front I drum as an adjacent tube in the same row longitudinally of said front bank, and tubes arranged to pass through the spaces left by the bending of said bent tubes and connecting said rear drum to said superheater tubes.

5. A water tube boiler comprising front, middle and rear upper drums, a mud drum below said upper drums, vertically extending front, middle and rear banks of tubes connecting said front, middle and-rear drums to said mud drum respectively, said rear? drum being arranged relative to said middle and front drums'so that the bottom of said rear drum is substantially higher than the top of said middle drum, and said rear tube bank having a substantially lower number of rows of tubes transversely of said rear drum than the transverse tube rows in said middle and front banks, circulator tubes arranged to connect said front and middle drums above and below the normal water level in said middle drum, circulator tubes arranged to connect said middle and rear drums only above the normal water level in steam outlet from said said middle drum, and a rear drum.

DAVID S. JACOBUS.