US1815086A - Steam generator - Google Patents

Description

July 21, 1931. A. c. WOOD STEAM GENERATOR 1 d m m c.

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A TTORNEY July 21, 1931; A. c. wboD 1,815,086

STEAM GENERATOR Filed Oct- 9, 1926 3 Sheets-Sheet 2 IN VE N TOR ATTORNEY juiy 21, 1931. A. c. WOOD STEAM GENERATOR Filed Oct. 9 192 S Sheets+Sheet 5 m w N N IN VEN TOF? jibe/Z Cit 00d oHooo A TTOHNE Y Patented July 21, 1931 PATENT oF lcE ALBERT C. WOOD, OF PHILADELPHIA, PENNSYLVANIA STEAM". GENERATOR Application fll'ed October 9, 1926. Serial No. 140,437.

My invention is designed to provide a steam generator of high efliciency particularly adapted for using fuels which, can be burned in suspension, and providing a furnace and primary boiler elements of integral construction affording extended surface contact between the products of combustion and the surfaces of compactly arranged circulating elements. My invention minimizes the number of drums required and avoids the necessity for the numerous baflles heretofore commonly used, the courses of theheating gases being primarily controlled by the inherent design of the combustion chamber and] fuel feeding means and the regulation of. the air supply. By my improvements, the generator may be efficiently and economically operated even when the gases leave the primary boiler elements ata comparatively high temperature m'nce further heat is absorbed from the gases before discharge to the stack by auxiliary economizing devices for preheating fluids utilized in effecting the generation of steam.

My improvements are preferably embodied in a steam generator having a combustion chamber with walls cooled by fluid circulating tubes adjacent thereto and communicating with horizontal drums arranged one above the other at one side of the combustion chamber the drums being further connected by sets of upflow and downflow tubes spaced by a baffle. I preferably use fluid fuel. such as powdered coal, wood waste, oil or gas, which can be injected into the combustion chamber at such angle to a wall thereof .protected by heat absorbing tubes that the combustible gases are deflected by the wall and by the admission of an auxiliary air supply so as to form substantially nonconfiicting currents flowing in reverse directions in the combustion chamber..

The circulating tubes protecting the walls of the combustion chamber preferably meet at right angles, and either communicate directly with the drums or connect with tubes or headers communicating directly with the drums. The tubes at the top and bottom of the combustion chamber are arranged radially to and communicate directly with the drums and are preferably inclined to the horizontal, the downward discharge of water. and the segregation of steam from the water being thereby facilitated.

The products of combustion discharged from the combustion chamber are preferably delivered to upright approximately parallel flues in which are contained the downflow tubes of the primary steam generating system; and also heat absorptive devices such as economi'zer tubes, air preheaters, and steam superheaters, although the latter may be positioned in the path of the heating gases before the discharge thereof from the primary steam generating system.

The fuel is preferably fed to the combustion chamber through a flaring passage supplied from a hopper or reservoir with regulated amounts of powdered or liquid fuel, and a regulated volume of heated air is combined with the fuel in its passage to the combustion chamber. Further regulated volumes of heated air are supplied to the opposite end of the combustion chamber to divert the current of incandescent or highly heated gases in a direction opposite to the initial movement thereof, intensify the combustion, and protect the tubes at the end of the combustion chamber where the course of the gases is reversed.

My improved generator is particularly adapted for assembly in batteries of pairs,

each pair having flues containing the economizing devices and disposed adjacent to one another, and the spaces between the ends of adjacent pairs providing room for working platforms and air control mechanisms.

The characteristic features and advantages of my improvements will more fully appear from the following description and the accompanying drawings illustrating embodiments thereof.

In the drawings, Fig. 1 is a vertical sectional view through generating units illustrating my invention, portions of one of the units being omitted and parts of an adjacent pair of units being shown diagrammatically in elevation; Fig. 2 shows the construction illustrated in Fig. 1, with the top of the fuel hopper and some other parts omitted, the view being partly in top plan and partly along a horizontal section taken on the line 22 of Fig. 1 above theeconomizer and below the air preheater; Fig. 3 is a vertical sectional view chamber wall or lining of a slightly modified form. 5

The generating units A, B, B, etc. are preferably mounted in pairs to form batteries within a setting 1 and are suitably supported on foundations 2.

Each generating unit comprises a pair of horizontal drums 3 and 4 arranged one above, but not necessarily over the other, in the setting and connected by upright primary generating tubes consisting of the bank or nest of upflow tubes 5 and the bank" or nest of downflow tubes 6. These generating tubes are preferably inclined to the vertical approximately one inch to the foot through the greater part of their lengths and have bent ends disposed substantially normal to the peripheries of the drums.

The respective banks of upfiow and downflow tubes are separated through the greater part of their lengths by a battle wall 7 resting on tubes 5 and provided with deflectors 7 for directing the hot gases outwardly toward the tubes 6. Y

A pair of headers or tubes 8 project from the drum 3-adjacent the ends thereof, and preferably radially thereto, and the outer ends of these headers may be connected by a transverse header 9. A pair of headers or tubes 10 project from the drum 4 substantially parallel with the headers 8 and may have their outer ends connected by the transverse header 11. The drum 3 is connected with the header 9 by a row of prostrate tubes 12; the

headers 8 are connected with the headers 10 ber or furnace surrounded on all sides by water tubes communicating with the steam and water drums, the chamber having its top, sides and end walls rendered resistant to the effects of high temperatures by absorption therefrom of heat by the circulating tubes, which are preferably soYconnnected with the lining blocks as to afford maximum exposed tube areas. The lining members are preferably provided with angular wings conducing to uniformity in the transmission of heat through different portions of the peripheries of the tubes, and the tubes and lining members are held in intimate extended surface contact by fasteners 13a integral with the tubes, protectedgthereby from the direct action of the heat and extending through apertures in the furnace lining, as set out in my application Serial No. 104867.

Fuel, combustible in suspension, and preferably powdered coal, is supplied to the combustion chamber from a hopper 17 by means of a rotary cylindrical feeder 18 containing a plurality of staggered diametral passages. Reciprocable pistons or plugs 19 separate the respective passages into pockets 20, 20. As the feeder rotates, the respective pistons drop in sequence to the lower parts of the respective passages and eject fuel from the lower pocket; this movement of the piston enlarging the complementary upper pocket which is filled with fuel having little or no air occluded therewith. Other fuels, such as gas, oil or sawdust may be conveniently used for heating the generator, such gaseous, liquid or finely divided solid substances being referred to herein as fluid fuels.

The fuel is deposited by the feeder in supply passages 21 each having an air port 22 and a flaring mouth 23 discharging fuel into the combustion chamber between the tubes 12 and toward the tubes 15. The primary supply of air for carrying on'combustion is mixed with the fuel in its passage through the passages 21 and is supplied from a header 24 under :control of a valve 25 operable by the link 26, crank arm 27, shaft 28, gear 29, worm 30 and pulley 31.

Preheated air under pressure is supplied to the header 24 from a conduit 32 communicating with the horizontal air preheater tubes 33, disposed in the .upright flue 34, and connected with a blower 35. A branch conduit 32 supplies preheated air under pressure to a header 36, which in the form shown in Figs. 1 and 2 communicates through a valve 37, similar to the valve 25, with flaring nozzles 38 discharging beneath the tubes 16.

Economizer tubes 39 may be disposed in the flue 34 beneath the preheater tubes 33 and preheat the water supplied to the drum 3 through the pipe 40.

In the form of apparatus shown in Figs. 1 and 2, a superheater. 41, communicating with the steam drum 3 through the conduit 42 and having a superheated steam outlet 43, may be disposed adjacent to the tubes 6 in the passage 44 between the inclined bafile 7 and the flue 34, as shown in unit A, or a somewhat modified form of superheater 41 may be disposed in the flue 34, as shown in unit B.

It will be understood that, in the operation of a unit, water will be supplied to the drum 3, preferably after passing through economizer tubes 39, and flow from the drum through the main and auxiliary circulating tubes and. the drum 4, the tubes 12 and 16 being inclined to the horizontal and the former openin into the drum 3 beneath the guard plate 3' therein and below the water level. The connections of the tubes at the top, sides, outer end and bottom of the combustion chamber preferably form right angles, so that the combustion chamber has the general form of a parallelepiped with banks of upright primary generating tubes at an end thereof.

Air is forced'by the blower 35 through the preheater tubes 33, conduit 32, header 24 and passages 23 into the combustion chamber and draws with it fuel supplied by the feeder 18, the stream of air and fuel being combustible in suspension and delivered to the combustion chamber at such, an angle as to cause the stream of burning fuel and gases to. sweep toward and downwardly in contact with or in proximity to the tubes 15, as indicated in dotted lines (Figs. 1 and 3).

In the form of apparatus illustrated in Figs. 1 and 2, the heated gases are deflected outwardly by the lining and wall behind the tubes 15 and its movement upwardly along the tubes 5 is facilitated by currents of heated air discharged between the bottom tubes 16 from the nozzles 38; the ashes dropping between the tubes 16 into the ash pit 2' from which they may be removed by a suitable conveyor passing through and sealing the aperture 2".

The current of heated gases flowing up the bank of upright tubes 5 escapes between thetop of the baflle 7 and the bottom of the drum 3 and flows downwardly over the tubes 6, being diverted outwardly by the deflectors 7'. The gases are discharged from the combustion chamber at a temperature sufiiciently high to efiiciently superheat the steam in the tubes 41 or 41' and any excess heat is utilized in heating the economizer tubes 39 and preheater tubes 33 in the flue 34, from which the gases escape to the stack at a comparatively low temperature. In the primary generating tubes, the circulation of water is upward in the bank of upright tubes 5 and downward in the bank of upright tubes 6, while in the wall cooling system the circulation is outwardly and downwardly from the lower drum, through the row of tubes 16 and headers 10, and upwardly through the rows of tubes 14, 15, 12 and headers 8 to the top drum. a

In the modified construction shown in Fi g. 3, the combustion chamber is not enclosed in a closely fitting casing but is spaced from the setting walls 2a.. The space between the lining plates 13 or 13" and the setting walls' 20 is divided into chambers 45, 46, 47 48 by partitions 49, 50, 51, 52. Access to the chambers 45, 46 may be had through manholes 45', 46 provided with detachable closures 45", 46 for the manipulation of tubes, admission of air or removalof dirt.-

The air supply conduit 32' is controlled by a damper 53 and the header 36 discharges to the chamber 48, which communicates with the chamber 47 and ash pit 2 through the ports 55 and 56 controlled by the dampers 57 and 58 operable by link and lever mechanisms 59 and 60. Where desired, a portion of the top of the combustion chamber may be closed and a part provided with passages or apertures for the admission of air from chambers 45 and 46, which may be supplied through a branch preheated air. flue or through the manholes.

The primary generating system is augmented by drums 3a and 4a connected with the drums 3 and 4 by sets of tubes 61, 62, 63. The drums 3a and 4a are connected by a bank of upright upflowtubes 5a and a bank of upright downfiow-t-ubes 6a inclined and bent similarly to the tubes 5 and 6.

A bafiie wall 64 extends from the drum 3a downwardly along and is supported by the upper parts of the tubes 5a, the bafiie being provided with a deflector 64' substantially parallel with a deflector 7 a on the baffle wall 7. A baflie wall 65 extends from the drum 4a upwardly along and is supported by the tubes 6a and is provided with a deflector 65 and a b'aflie wall 66 extends from the drum 3a downwardly along and is supported by the upper parts of the tubes 6a. The baflies may be formed of plates similar to those shown in Figs. 4 and 5 and aflord circuitous passages or flues providing extended contact of the heating gases with the tubes, as indicated in dotted lines.

A steam superheater 41", set in the passage between the drum 3 and deflector 7a, is supplied with steam from the drum 3a through the pipe 42 and discharges superheated steam from the outlet 43'.

When the generator is being worked at a low rate, the gases are sufiiciently cooled on leaving the tubes 6a for discharge through a flue 68 directly to the stack 69, this course of flow of the gases being controlled by a damper 70 between the stack and flue. But when the generator is being worked at a high rate so that the gases are discharged from the tubes 6a at a comparatively high temperature the damper 70 may be closed the blocks 13, 13" from the chambers 45, 46, 47, 48 and 2'. .Theauxiliary air supply may be so regulated as to aid in protecting the tubes and blocks as well as diverting the current of gases flowing downwardly along the tubes 15 in a reversecourse upwardly along the tubes as indicated in dotted lines. The gases then flow over the superheater tubes, the auxiliary generating tubes,

and through eitherthe flue 68 or 34, to the stack.

no not unduly impede the flow of gases or $uch bafiles as are required in my generator a'reffreadily installed and maintained,

l heat absbrption, and do not'collect thereon substantial amounts of soot.

It will be evident that structural changes or modifications may be made without departing from my invention. For instance,

the ends of the headers 8, 9, and 11 may be capped instead of connected as shown, or the headers 9 and 11 may be eliminated entirely and the tubes 12, 15 and 16 joined to form independent circuits. It is generally desirable to have the tubes protecting the side walls of thecombustion chamber substantially parallel with the intermediate straight portions of the main generating tubes, hence if the drum 3 is disposed Vertition, the preheating of the air may be unessential, though in practically all cases where complete furnace wall cooling is provided it will be desirable to use an air preheater. When the generator is working at a low rate or a suflicient number of upright steam generating tubes are provided to reduce the temperature of the gases reasonably low, say 450 degrees to 550 degrees F., the air preheater and economizer may both be dispensed with, as shown in Fig. 3, without detracting from the advantages'derived from positioning the banks of upright generating tubes in a unitary arrangement with the combustion chamber or from feeding the fuel and effecting and controlling the circulation of water, air and heating gases in the manner described.

Moreover instead of providing separate fines and heat absorptive devices for each boiler of a battery, as shown in the drawings, the boiler units of a battery may discharge to a common flue containing heat absorptive devices serving both units.

Having described my invention, I claim: 1. A steam generator comprising a combustion chamber having a ,water cooled wall at one side thereof and a bank of up-flow generating tubes and a complementary bank of down-flow generating tubes at the other side thereof, means for discharging combustible products at an angle across a substantial portion of said chamber and toward one side of said chamber and along said wall, and means for diverting the course of products of combustion from said combustible products toward the other side of said chamber and in contact with said bank of up-flow generating tubes and thence downwardly over said complementary bank of down-flow generating tubes.

2. A steam generator comprising a plurality of drums disposed one above the other, headers and tubes projecting from the respective drums, tubes connecting the outer ends of the tubes projecting from one drum with outer ends of the tubes projecting from the other drum, and tubes connecting intermediate sections of a header projecting from one drum adjacent to an end thereof with intermediate sections of a header projecting from the other drum adjacent to the corresponding end thereof.

3. A steam generator comprising a plurality of drums disposed one above the other, substantially straight tubes projecting from said drums and substantially parallel with one another, tubes connecting the tubes projecting from the respective drums-and in the planes thereof, and further upright tubes connecting said drums and having sections normal to the peripheries of the respective drums.

4:. A steam generator comprising a combustion chamber having water tube side walls with blocks fixed thereto, and a top and bottom formed of parallel spaced prostrate tubes, an upright baflie at one side of said combustion chamber and having upright tubes on. opposite sides thereof, a flue having preheating tubes therein, a superheater disposed in the path of gases flowing from said combustion chamber to said preheating tubes, means for discharging fuel between spaced tubes of said top and means for introducing the primary air supply between the.

spaced tubes of said bottom.

5. A. steam generator comprising a pair of drums set one above the other in a horizontal position, inclined upflow and downflow tube banks connecting said drums, tubes projecting from and inclined downwardly from each of said drums and forming the top and bottom of a tube-enclosed combustion chamber,

6. A steam generator comprising apair of 1 drums set one above the other in a horizontal position, inclined upflow and downflow tube banks connecting said drums, tubes projecttom and one side of said chamber ing'from and inclined downwardly from each of said drums and forming the top and bottom of a tube-enclosed combustion chamber, inclined tubes forming walls of said combustion chamber, said combustion chamber being adjacent to said upflow tubes, and means for directing a current of products of combustion downward toward inclined wall tubes aforesaid and then upward toward said upflow tubes, a baflie between saidv upflow and downflow tubes, an air preheater in the path of gases flowing from said downflow tube bank, and means for conveying air from said preheater beneath said bottom inclined tubes.

7. A' steam generator comprising a combustion chamber completely enclosed by inclined tubes, the'tubes forming the top botbeing spaced to form'passages between said chamber and the exterior, means for directing acurrent of products of combustion diagonally downward from said spaced top tubes, means for directing the primary air current diagonally upward from said spaced bottom tubes, and a bafiie deflecting the combined currents aforesaid upwardly and downwardly over the spaced side tubes aforesaid.

In witness whereof I have hereunto set my name this'8th day'of October, 1926.

ALBERT O. WOOD.

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