US2170349A

US2170349A - Forced flow vapor generator

Info

Publication number: US2170349A
Application number: US113060A
Authority: US
Inventors: Ervin G Bailey
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1936-11-27
Filing date: 1936-11-27
Publication date: 1939-08-22
Anticipated expiration: 1956-08-22

Description

Aug. 22, 1939.

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Aug. 22, 1939. E. G. BAILEY FORCED FLOW VAPOR GENERATOR 6 SheetsSheet 2 Filed Nov. 27, 1956 IIL INVENTOR.

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ATTORNEY.

Aug. 22, 1939. E. G. BAILEY' 2,170,349

FORCED FLOW VAPOR GENERATOR Filed Nov. 2'7, 1936 6 Sheets-Sheet 3 j'uperbeazer Inlet INVENTOR.

Y Ervz'n G. Bailey ATTORNEY.

Aug. 22, 1939. E. G. BAILEY FORCED FLOW VAPOR GENERATOR Fiied Nov. 27, 1936 I 6 Sheets-Sheet 4 h wm Aug. 22, 1939. E. G. BAILEY FORCED FLOW VAPOR eaNEamo-n e Shets-Sheet 5 Filed Nov. 2'7, 1936 A'iTORNEY.

Aug. 22, 1939.

E. G. BAILEY FORCED FLOW VAPOR GENERATOR 6 Sheets-Sheet 6 Filed Nov. 27, 1936 INVENTOR. B Lin 1'12 G. Bailey ATTORNEY.

7?: Steam Separ'aior Patented Aug. 22, ,1939

PATENT OFFICE FORCED VAPOR GENERATOR Ervln G. Bailey, Easton, Pa., asslgnor to The Babcock & Wilcox Company, Newark, N. 1., a cor- .poration of New Jersey Application November 21, 1936, Serial No. 113,060

9 Claims.

This invention is a light weight compact forced flow vapor generator with minimum liquid and heat storage for a maximum heat absorbing surface, particularly adapted for generating superheated steam at high pressure while maintaining practically uniform temperature and pressure over a wide range of substantially instantaneous load variations, thus rendering this vapor generator acceptable for variable speed motive 10 power applications in a range of sizes suitable for locomotive, ship and other classes of service demanding minimum weight and standby expense.

As in my co-pending applications Serial No.

55,020 and Serial No. 55,021 the vapor generator of the present inventionis characterised by a fluid path comprised of small bore tubes of great length'arranged in multiple for parallel flow to secure the desired capacity, and into which fluid 0 path liquid is introduced at one end and steam and water taken from the other; the water passes therethrough in suiilcient volume and in a manner to limit concentration of scale forming substances while, at the same time, maintaining tube metal temperatures within a safe range.

' At the end of the generating section the steam and water are separated, saturated steam passes to a superheater while excess water may be removed from the system after recovery of heat, or

may be recirculated in part with any incoming make-up water; the method of operation and apparatus for carrying out the operation, as set forth in .the hereinbefore identified applications, in combination with certain methods of operation and apparatus of the present application are a part of this present invention.

The steam generator of this present invention includes three separate parts or chambers, and the term "chamber as herein used is a wall- 40 enclosed space with'inlet and outlet openings for the flow of gas through it while the gas is in heat transfer relation to the working fluid flowing in tubes located in the walls or across the space between walls. The three chambers are, namely,

a combustion chamber fired by fluid or solid fuel and air, a tube bank chamber, and an intermediate gas chamber. The intermediate gas chamber has a bottom inlet from the combustion chamber and a bottom outlet to the tube bank or convection chamber, the inlet andoutlet to and from said intermediate gaschamber being directly opposite but screened from each other by a cooled partition extending upwardly from the bottom and which, being at low temperature is' incapable of intensively re-radiating.

(c1. 122 -2so) The walls of this gas chamber as well as its partition are heat absorbing surface for lowering the temperature of the hot products of combustion to the desired degree before they are per- -mitted to contact the subsequently positioned 5 tube banks, such as a superheater, in the convection chamber, thus the intermediate gas chamber, which is constructed to be free of'any crossing tubes, has the triple effect of screening the tube banks from furnace radiation, lowering 10 the temperature of. the hot. gases of combustion, and mining the said gases for uniformity of temperature throughout the cross-section of the gas & stream while, at the same time, not imposing any substantial additional flow resistance or draft 5 loss.

A feature of the invention is the arrangement of the long small bore tubes of the fluid circuit in such manner that certain tubesare incorporated in and, in some .instances, form a total 20 wall of the combustion chamber and of the intermediate gas passage. I v

The invention also provides an. arrangement of heat absorbing surface such that there are no tubes crossing the opening or path between the combustion chamber and intermediate gas passage or the opening between the said gas passage and the tube bank chamber; also this is accomplished without headers within the combustion chamber or intermediate gas chamber which, if 5 present, would necessarily interpose metal parts having walls of greater thickness, due to'their larger size, than the metal wall thickness of the tubular heat absorbing surface.

With the foregoing in view, and for the purpose 35 of satisfying the patent statutes, I shall now describe a practical embodiment of this invention in reference to the accompanying drawings, wherein I have illustrated the same and in which-- Fig. 1 is a diagrammatic vertical sectional elevation illustrative of the hot gas and fluid flow paths.

Fig. 1 is a diagrammatic view in vertical sectional elevation illustrating the manner of combining. the combustion chamber, intermediate gas chamber, and convection chamber.. 0

Fig. 2 is a sectional elevation of the vapor .gen-

erator. I u

Fig. 3 is a sectional elevation in the plane of w the line 3-3 of Fig. 2. i

Fig. 4 is, a view similar to Fig. 3 on the plane of the line 4-4 of Fig. 2..

- Fig. 5 is a transverse sectional elevation on the plane of" the line 5-5 of Fig. 2.

and l is in three separate parts, namely, a

combustion chamber A, a tube bank or convection chamber C and an intermediate gas chamber B.

The intermediate gas chamber B has a bottom inlet E from the combustion chamber A and a bottom outlet F to the tube bank or convection chamber C, these openings are directly opposite one another but are screened from each other by a cooled partition G extending upwardly from the bottom and which, being maintained at 'rel-. atively low temperature by heat absorbing surface, is incapable of re-radiation.

The walls of this intermediate gas chamber B, as well as its partition G, are heat absorbing surface, as shown in Fig. 8. The multiple long small bore fluid flow conduits l and 2 providing this heat absorbing surface are supplied with liquid through resistors in the manner described in my hereinbefore referred to co-pending applications.

The conduit l passes around the inside of the bottom of the generator back and forth across the floor of all three chambers in return bend loops, across .to form a part of the partition G, and then rises, in the combustion chamber A, to a location above the level of the top of the bottom opening between said combustion chamber A and the intermediate gas chamber B; from this level it continues, in helical convolutions, up-

wardly to the level of the top of the intermediate gas chamber B; here it crosses back and forth, in horizontal return bend loops, to form heat absorbing surface for the roof of said intermediate gas chamber B, then again returns to the combustion chamber A where it is coiled helically and spirally upwardly and inwardly to thereby provide a conical burner throat D receiving a burner, as indicated, for finely divided fuel such as oil or pulverized coal.

The upper end of conduit l discharges into the separator 3 for'steam and water as shown, such separatorhaving a safety valve 4 and a handhole 5. The separator is fullydescribed in my hereinbefore referred to pending applications.

A second long small bore tubular conduit 2 for the fluid is first coiled aroundthe inside of the lower portion of the gas chamber C, thence extends transversely to provide a part of the cooled partition G, as does also the conduit I in its lower portion, and then takes several turns around the combustion chamber A and lower portion of the chamber C up to the level of the top of the bottom inlet and outlet of the intermediate gas chamber B where it next begins a distorted figure eight form such .that it provides alternate substantially horizontal lengths with conduit I to form the partition H in the nature-of a hung wall dividing combustion chamber A from the intermediate gas chamber B; the central portion of this distorted figure eight forms substantially horizontal .superimposed lengths providing the remainder of the upwardly extending cooled partiheat thereacross, whilethe remainder of this conduit 2' forms heat absorbing surface in the other wall I separating the intermediate gas chamber B from the tube bank chamber C; the upper end of conduit 2, like I, then discharges to steam and water separator 3.

Thus, as described in the foregoing the heat absorbing surface defines a combustion chamber vA of substantially cylindrical form with a burner for finely divided fuel at the upper end originating its flame in a conical entrance and'pro- J'ecting it downwardly close to the walls. As shown, the walls, floor and roof of both the combustion chamber Aand intermediate gas chamber B are fluid cooled. The portion of the combustion chamber wall formed by the partition H and also the partition G are formed substantially throughout their height by superposed contacting tube lengths, while the superposed tube lengths lining the remaining wall portions of the combustion chamber and gas chamber are separated by refractory material. The tube lengths forming the partition G and the gas chamber side .of the tube lengths forming the partition H are directly exposed,-while the opposite side of the tubes in the partition H and the tubes in the balance of the combustion chamber wall and floor are studded to key a thin layer .of refractory 29 I The separator 3 located just above the upper end of the intermediate gas chamber B disposed of its spillover or excess Water separated from the saturated steam, under regulated conditions,

as set forth in my co-pending applications, and

through heat transfer surface 28 in the form of acoil arranged partly in the air' intake for the upper portion 23 of a tubular air heater and partly in the air exit passage 26 to the burner from the lower portion 24 of the air heater; these portions of the said air heater are connected by an air passage 25, and the passage 26 leads to the wind-box 21 at the burner entrance. The wind-box 2l'is provided with suitable vanes, as shown, to proportion the air delivery and change its direction for entrance to the burner throat.

The air heater is located in the cooler end of the tube bank chamber C. In the hotter end of this chamber is a two-pass superheater tube bank 8 receiving saturated steam from the separator 3, through the manifold pipe 6 which leads to the inlet header 1; from this header I the saturated steam travels through the return bend loops upwardly of one-half 'the superheater to the header 9, thence downwardly through the other half of the superheater to the header I0 and out the bottom of the intermediate gas chamber B to the tube bank chamber 0.

Each tube coil of the superheater bank is supported at its inner end from a bracket l2 securedto the tubes of the partition I and over which bracket is engaged a hook l3 carried on a bar or plate I at the upper end of each tube coil.

v Plates l5 are welded between the remaining superheater tube loops at each end of the tube coils.

Each tube coil is thus supported at opposite ends from the bracket l2 and the upper header 9.

Spaced above the superheater tube bank 8 in the tube bank chamber C is an economizer I6 comprising plural vertical coils l8 of return bend form connecting inlet header l1 and outlet header [9. The economizer tube bank l6 has its upright flat coils l8 carried opposite to the header end by the vertical bars or plates 22 supported at 2| on a bracket 20 supported on the tubes of the partition I. v

Accessibility to the intermediate gas chamber B is provided through the removable panel portion J indicated in Figs. 2 and '7.

If pulverized coal is used in the operation of this generator a suitably located slag outlet is provided in the floor or side wall of the furnace at a highly heated location such as is indicated diagrammatically at K in Fig. 1, the tubular conduits being adjusted in position in the fabrication of the steam generator to provide for this openmg.

While, in the foregoing, I have described a practical embodiment of the invention, it is to be understood that the method of operation and the structural details may be altered without departing from the scope of the invention as defined in the appended claims. The general construction and arrangement of the furnace chamber, tube bank chamber, and intermediate gas chamber are disclosed and claimed in my co-pen'ding application, Serial No. 88,285, filed July 1,

I claim:

1. In a forced circulation vapor generator, a combustion chamber and gas chamber with upright side walls, the walls of which are principally formed of a plurality of coiled long small bore fluid flow conduits arranged uprightly in stacks with the convolutions of one stack alternating with and overlying portions of those of another to provide a substantially continuous heat absorbing surface forming at least one wall of the gas chamber.

2. In a forced circulation vapor generator, a combustion chamber and gas chamber with upright side walls, the walls of which are principally formed ofa plurality of coiled long small bore fluid flow conduits arranged uprightly in stacks with the convolutions of one stack alternating with and overlying portions of those of I another in the same wall surface to provide a substantially continuous heat absorbing surface forming at least one Wall of the gas chamber.

3. In a forced circulation vapor generator, a combustion chamber and gas chamber, the walls of which are .principally formed of a plurality of coiled long small bore fluid flow conduits arranged side by side in stacks with the convolutions of one stack alternating with and overlying portions of those of another in the same plane to provide a substantially continuous heat absorbing surface forming at least one wall of the gas chamber, one of said stacks additionally having portions superimposed upon each other to-provide another wall of said gas chamber.

4. A forced flow vapor generator comprising means forming, a combustion chamber and a laterally displaced tube bank chamber, a fuel burner for burning a fluid fuel in suspension in said combustioncham'ber, a gas chamber intermediate and serially connecting said combustion and tube bank chambers, said means including a plurality of long small bore fluid heating tubes arranged for parallel fluid flow therethrough, one

substantially horizontal tube lengths arranged in of said tubes including substantially horizontal continuous tube lengths defining a portion of substantially all of the vertical outer walls of said vapor generator and extending in alignment to define an internal wall, transversely of saidgas chamber, and a convection heated tube bank in said tube bank chamber.

5. A forced flow vapor generator comprising means forming a combustion chamber and a laterally displaced tube bank chamber, a fuel burner for burning a fluid fuel in suspension in said combustion chamber, a gas chamber intermediate and serially connecting said combustion and tube bank chambers, said means including a plurality of long small bore fluid heating tubes arranged for parallel fluid flow therethrough, each tube in-- cluding substantially horizontal tube lengths defining at least a portion of the same vertical wall of said combustion chamber, some of said substantially horizontal tube lengths of separate tubes being alternately arranged in superposed relation in said combustion chamber wall, and a convection heated tube bank in said tube bank chamber.

6. A forced flow vapor generator comprising means forming a cylindrical combustion chamber and a laterally displaced tube bank chamber, a a fuel burner for burning a fluid fuel in suspension in a downwardly directed stream in said combustion chamber, a gas chamber intermediate and serially connecting the lower ends of said combustion and tube bank chambers, said gas chamber having a vertically disposed partition therein separating the gas inlet and outlet connections to said chamber, said means including a plurality of long small bore fluid heating tubes arranged for parallel fluid flow therethrough from a lower to a higher level, each tube including substantially horizontal tube lengths defining at least a portion of the same vertical walls of said combustion and gas chambers and said gas chamber partition, some of the substantially horizontal tube lengths of separate tubes being alternately arranged in superposed relation in a wall of said combustion chamber, and a convection heated tube bank in said tube bank chamber.

A forced.fiow vapor generator comprising means forming a combustion chamber and a laterally displaced tube bank chamber, a fuel burner for burning a fluid fuel in suspension in said combustion chamber, a gas chamber intermediate and serially connecting said combustion and tube bank chambers, said means including a plurality of long small bore fluid heating tubes arranged for parallel fluid flow therethrough, one of said tubes having superposed serially connected tube lengths arranged in a substantially figure 8 formation to define the outer walls of said vapor generator and a transverse internal wall of said gas chamber, and a convection heated tube bank in said tube bank chamber.

8.'A forced flow vapor generator comprising means forming a combustion chamber. and a laterally displaced tube bank chamber, a fuel burner for" burning a-fluid fuel in suspension in a downwardly directed stream in said combustion chamconnecting the lower ends of said combustion and tube bank chambers, said gas chamber having a vertically disposed partition therein separating the gas inlet and outlet connections to said chamber, said means including a plurality of long small bore fluid heating tubes arranged for parallel fluid flow therethrough, one of said tubes having a horizontal substantially figure! formation to define the outer walls of said vapor generator and said gas, chamber partition, and a convection heated tube bank in said tube bank chamber.

9. A forced flow vapor generator comprising means forming a combustion chamber and a laterally displaced tube bank chamber, a fuel burner for burning a fluid fuel in suspension in a downwardly directed stream in said combustion chamber, transverse vertical walls defining opposite sides of a. gas chamber intermediate and serially connecting the lower ends of said combustion and tube bank chambers, said gas chamber having a vertically disposed partition therein separating the gas inlet and'outlet connections to said chamber, said means including a plurality of long small bore fluid heating 'tubes arranged for parallel fluid flow-ther'ethrough, one of said tubes having substantially horizontal tube lengths arranged in a horizontal substantially figure 8 formation to .define the transverse walls and partition of said in said tube bank chamber.

. .ERVmG.IBAJLEY.

gas chamber, and aQconvection heated tube bank 10