US2368211A

US2368211A - Vapor generator

Info

Publication number: US2368211A
Application number: US427403A
Authority: US
Inventors: Fletcher James
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1942-01-20
Filing date: 1942-01-20
Publication date: 1945-01-30
Anticipated expiration: 1962-01-30

Description

Jan. 30, 1945. J. FLETCHER VAPOR GENERATOR s Sheets-Shet 1 Filed Jan. 20, 1942 IINVENTOR. James F/ezfcher ATTORNEY Jan. 30, 1945. J, FLETCHER 2,368,211

VAPOR GENERATOR Filed Jan. 20, 1942 3 Sheets-Sheet 2 Fig.3

IN VENT OR.

JamesFZeicfzer AJTORNEY Jan. 30, 1945.

,1. FLETCHER VAPOR GENERATOR Filed Jan. 20, 1942 3 Sheets-Sheet 5 INVENTOR.

.Jame5 Fleficher ATTORNEY lets of the separators. utilizes this. same velocity in a manner to secure Patented Jan. 30, 1945 VAPOR. GENERATOR,

James Fletcher, Akron, Ohio, assignor to The Babcock & Wilcox Company, Newark, N. 1., a corporation of New Jersey AppncatmnJanuary 20, 1194a, Serial No. 427,403

4 Claims.

This invention relates to fluidheat exchange installations in which a vapor or gas is generatedfrom a liquid under conditions including high pressures. Theinvention more particularly relates to a type of steam generator in which a steam and, water drum, connected to one or more downcomers, is provided with a plurality of centrifugal steam and water separators arranged longitudinally of the drum. These separators receive steam and water mixtures through circulatory connections to the drum, these connections directly communicating with the inlets of the separators. The separators discharge separated water downwardly into the drum with a velocity sufiicient to overcome any static head resulting from a submergence of the water out- The present invention improved conditions of water flowwithin th dr m.

The improved steam and water separators of the present invention contribute to higherinitial flow velocities at the water outlets of the separators, and the separators are so arranged with reference to'the drum and its downcomers that each stream of separated water discharging from a separator merges with the streams of separated water'from adjacent separators, all of which are directed toward the nearest downcomer. This arrangement is particularly important in long boiler drums associated with a single .downcomer or, at most, asmall number of downcomers. In such a drum, the separated water from many of the separators must travel a. considerable distance longitudinally of the drum to reach a downcomer, and it is an important desideratum that drum water flow and water level conditions benot disturbed by this requirement. The separators of the present invention, arranged with their merging streams of separated water result in a higher average flow, of water longi; tudinally of the drum.

The invention will be better understood by reference to the following description of an illustrative steam generator indicatedin theaccompanying drawings, and other obiectsof. the invention will appear as the description proceeds.

'In the drawings:

Fig. 1 is a diagrammatic viewin the nature of a verticalsection longitudinally of a steam and water drum of a steamgenerator;

Fig. 2 isa plan section of a drum, showing the arrangement of steam and water separators h rein;

ig. 31 shows an endz rt n of the teamand. 55

by steam generating tubes.

water drum broken away to disclose' the steam and water separators on a larger scale;

Fig. 4 is a transverse vertical section as indicated by the line-4-4 of Fig. 3; v

Fig. 5 is an elevationshowing one of the steam and water separators on an enlarged scale;

' Fig. 6 is a vertical section on the line 6-. 6--of Fig. 5;

Fig. 7 is a horizontal section on the line 'I-.-.l

of Fig. 6;

Fig. 8 is a detail section on theline'.,8.-8 .of

Fig; 6;

Fig. 9 is a. diagrammatic view illustratingthe type. of steam generator to which the. invention is applied; and

Fig. 10v isa. diagrammatic view illustrating-the generic arrangement of partsof the circulatony system with whichthis invention is concerned.

The steam generator diagrammatically indicated in Fig.9 includes. a steamand water drum Hl' connected to a submerged header or drum I2 l4, l6, and I8, define walls of a. combustion chamber 20 fired'by a burner 22;

From the combustion chamber the furnace gases pass to a second furnace chamber H defined by the steam generating tubes. including the tubes [6. At the upper partof the chamber 24' the gases pass over successive screens .28 and 3| formed by spaced'upper portions of the tubes I4 and 16. Beyond these screens, such auxiliaries as a superheater, economizer and air heater may be disposed.

The steam generating tubes are distributed along the length of the drum is, as diagrammatically shown in Fig. 10, and the natural circulation circuit is completed by large diameter '

downcomers

30 and 32. These are preferably disposed exteriorly of the furnace chambers where they connect the ends of the drums ll] and I2. At high furnace temperatures. and high loads the steam generating tubes discharge steam and water mixtures into the, drug 10 at high velocities, and, in the drum, the. water is separated from the steam anddirected toward the ends: of the drum and the downcomers.

Thev steam and Water separation is effected. in the whirl chambers of centrifugal eparatorsdis posed within the drum ID as indicated in- Figs. 1-4. The separators are arrainged in two rows longitudinally of the drum. The separators 40, at one side of the drum, aresecured by their scrollinlets 44 to a .fixed upright plate lfi, while theseparators; fillratthe other sideof the.drum, h

Some of the latter,

are similarly secured by their inlets 54 to a similar fixed plate 56.

Other plate structures such as the plates 60, GI, and 62 are joined with the

upright plates

46 and 56 to form the inlet compartment 64. This compartment extends over the outlet ends of the steam generating tubes (such as 14 and IS) and receives all of the steam and water mixtures discharged therefrom. The compartment also extends longitudinally of the drum and its ends are closed at positions near the

downcomers

30 and 32 as indicated in Figures 1 and 3.

The inlet compartment 64 confines the steam and water mixtures discharged from the steam generating tubes (such as l4 and I6) and directs the mixture to the separator inlets with the result that the velocity of the mixture at the inlets is higher than at the outlets of the tubes. The high velocity stream entering a separator is deflected by the whirl chamber wall and the centrifugal action induced causes separation of the steam and water.

The restricted outlets 12 for separated water are annular openings formed between the whirl chamber bottoms 14 and the walls of the whirl chambers. Helical vanes 16 may be disposed within the outlets.

Below the bottom of each whirl chamber there is a shrouded nozzle such as shown in detail in Figs. 5, 6, 7, and 8. Each includes a downwardly inclined bottom plate 80 and an upper plate 8| between which there is an outlet 84 presented toward one side of the separator. The

plates

80 and 8| are joined by side plates 85--88 to complete the structure.

The water leaving the whirl chamber through the annular opening formed by the restricted outlet 12 has a whirling motion, and the shrouded nozzle confines this water and directs it in a wide thin stream toward a downcomer. When the separators are arranged with reference to the 1 downcomer as indicated in Fig. 2, the nozzles preferably direct the separated water in streams angled slightly inwardly of the drum, the outlets of the nozzles facing toward the downcomer.

The provision of side nozzle outlets with a relatively small vertical dimension not only promotes desirable merging of the water streams and their direction toward a downcomer with a minimum of interference with drum flow, but it also pro vides a. maximum flow area in the drum beneath the separators and their nozzles.

In the illustrative steam and water drum H), the separators A (Fig. 1) have right hand nozzles directing the separated water toward the downcomer 32, while the separators B, in the same row have left hand nozzles directing separated water toward the downcomer 30.

The separators 50 of the row at the other side of the drum are similarly formed as rights and lefts, and they are similarly arranged relative to the downcomers.

This arrangement contributes to higher water velocitie longitudinally of the drum and thereby effects better water level conditions.

Above the steam outlet of each separator and spaced therefrom there is a multiple plate separator 90. On one side of the drum the multiple plate separators rest on a shroud structure 92 secured to the plate 46, while a similar structure 94 supports similar auxiliary separators at the opposite side of the drum.

Steam passes from the drum l through the off-take tubes 96 after passing through the additional multiple plate separators 98 and I" (Fig. 4).

The illustrative arrangement of nozzles or discharge spouts for the separator accomplishes a substantial improvement in water flow conditions within the drum. This is done by utilizing the kinetic energy of the denser fluid discharged from the separators, and directing this fluid in the direction of liquid flow within the drum rather than discharging it in a direction normal to drum flow. When the denser separated fluid i discharged in a direction normal to drum flow, there must be an independent difference in head or level within the drum to produce drum flow in the desired direction. The necessity for such independent difference in head or level is avoided by the present invention.

What is claimed is:

1. In a steam generator, a steam and water drum, a large diameter downcomer at each end of the drum, upright whirl chamber steam and water separators arranged in a row longitudinally within the drum and disposed between the inlets of the downcomers, tangential whirl chamber connections through which steam and water mixtures pass at high velocity, separate water outlets through which separated water passes at high velocity downwardly from the whirl chambers, and oppositely arranged flow directors secured to the separators below said outlets and directed to cause the water discharged therefrom to flow longitudinally of the drum and toward the nearest downcomers.

2. In a vapor generator, means forming a vapor and liquid chamber, fluid separators of the kinetic type within said chamber and disposed in a row arranged longitudinally thereof, means including yapor generating elements causing vapor v and liquid mixtures to be discharged at high velocities into the separators, said separators having restricted outlets conducting separated liquid downwardly at high velocity toward the liquid space of the chamber, means including a downcomer conducting separated liquid from the chamber to the inlets of the vapor generating elements, the

chamber being of such length and said downcomer being offset longitudinall of said chamber relative to the separators to such an extent that there must be considerable flow of separated water longitudinally of the chamber on its way to the downcomer, and separate flow controlling means below the liquid outlets of the several separators and directed transversely of said downward liquid flow and longitudinally of the chamber toward the downcomer to cause the separated liquid to flow at high velocity longitudinaly of the chamber and toward the downcomer, said separate flow controlling means having their exit terminals spaced longitudinaly of said chamber and disposed at progressively greater distances from the downcomer.

3. In a steam generator, a steam and water drum, whirl chamber steam and water separaits water space, the drum being of such length and said downcomer being ofiset longitudinally of said drum relative to the separators to such an extent that there must be considerable flow of separated water longitudinally of the drum on its way to the downcomer, and separate flow controlling means below the liquid outlets of the several separators and directed transversely of said downward water flow and longitudinally of said drum toward the downcomer to cause the separated water to flow longitudinally of the drum and toward the downcomer, the separate flow controlling means for the diflferent separators having their fluid exit terminals spaced longitudinally of the drug water space, and disposed at progressively greater distances from the downcomer inlet.

4. In a water tube steam boiler, a steam and water drum, steam generating tubes exposed to heat and discharging mixtures of steam and water into the drum at high velocity, a plurality of separators arranged longitudinally within the drum with each separator constructed to provide an upright circular whirl chamber with an outlet through which steam is vented into the steam space of the drum, means connecting the water space of the drum to the inlets of said tubes and including downcomers leading from the drum, means whereby the steam and water mixtures from the steam generating tubes are directed tangentially into the whirl chambers, and means providing a restricted water outlet adjacent the perimeter of each whirl chamber, the drum being of such length and said downcomers being ofiset longitudinally of the drum relative to the separators to such an extent that there must be considerable flow of the separated water longitudinally of the drum on its way to the downcomers, and a nozzle below the lower end of each whirl chamber directed longitudinally of said chamber toward the downcomer and transversely of the downward flow from said restricted outlet to cause flow of the separated water at high velocity longitudinally of the drum and toward a downcomer, the fluid exit terminals of said nozzles being spaced longitudinally of the drum and disposed at progressively greater distances from a downcomer.

JAMES FLETCHER.