USRE18901E - Water-tube steam boileb - Google Patents

Description

Re. 18,901 3 Sheets-Sheet 2 E. J. FRANKLIN WATER TUBE STEAM BOILER July 25, 1933.

Original Filed July 7. 1925 n M m T A INVENTOR.

m M m F, J 4 W a. f

posed to combustion chamber.

Reissued July 25, 1933 UNI ED- STATES T Re. 18,901

PATENT OFFICE EDWARD J; FRANKLIN, or SALT LAKE CITY, UTAH I WATER-TUBE) STEAM. BOILER Original No. 1,634,139, dated June 28, 1927, Serial No. filed October 2,1931.

This invention relates to water tube steam boilers, and more especially to a novel arrangement of boiler and rear or brldge wall are to expose a greater tube surface to the radiant heat of the furnace; to eliminate the necessity of a fire brick bridge wall; to pro-. vide maximum combustion space with given boiler setting dimensions; to provide a more suitable pocket or chamber for the collectlon and easy disposal of ash, flue dust or soot which may collect from the back passes; to

increase the circulation of water in the boiler, V and especially in the lowest row of tubes and thus prevent deposition of scale or sed ment with the resultant failure of tubes; to protect the furnace brick work both by direct screening effect of back. and side walls and by rei ducing the heat in the combustion chamber; to reduce furnace maintenance costs by eliminating large fire brick bridge walls commonly in use, and by reducing furnace temperatures due to increased radiant heating surface ex- The invention is particularly applicable to the straight tube type of boilers such as the Heine, Babcock & Wilcox,- Edgemoor and Case -Hedges steam boilers, but is also applica le with certain modifications to other types of water tubes such as the bent tube boilers of Stirling or similar types.

The accompanying drawings illustrate embodiments of my invention and referring thereto: Figure 1 is a longitudinal section of a.

straight tube boiler provided with my improved water tube bridge wall baflie. v

Fig. 2 is a section on line 22 in Fig. 1,

my with part of the frontheader broken away.

Fig. 3 is a section on line 33 in Fig. 1.

Fig. 4' is a section on line 4:l in Fig. 1.

Fig. 5' is a view similarto Fig. 1 showing the application of the invention to a straight 43'? tube boiler of a somewhat difierent construction. I 1

Fig. 6 is a partial section showing a different location of the water circulating system for the lower row of tubes. I

- ,Fig. 7 .is a longitudinal sectionof a bent The main objects of the invention 7 Serial No. 566,542.

tube boiler'provided with a bridge wall baflle according to my invention.

Fig. '8 is a section on line 8 8 in Fig. 7. Referring to Figs. 1 and 2 the steam boiler therein shown comprises a series or bank of 41,963, filed July 7, 1925. Application for reissue water tubes 1 connected to forward and rear headers 2 and 3 which are also connected to the steam drums 4. The usual meansare provided for drawing off steam from the steam ing' from the fire-box to the stack and 'de-' fiect such gas so as to cause same to pass several times between the water tubes in well known manner. The baffle plate 10 may be arranged in accordance with'the usual practice, preferably inclined or obliquely extending from' nearly the top'of the water tubes toithe bottom thereof in a downward and rearward direction and according to my invention a supplementary or additional baffie means 16is provided, preferably in line withj this baflle plate 10, and formed of firebrick, iron or'other suitable refractory material supported and protected by water tubes as hereinafter described.

In applying my invention to a boiler of the straight tube type I prefer to bend the lower row of tubes indicated at 1' downwardly where they approach the inclined baffie plate 10 and to extend said tubes in oblique downward direction to the rear end of,

Said downwardly bent por the fire-box. tions may extend at any suitable angle, for

example at an angle'of from 30 to 75 tothe horizontal. In the form shown the rearv portions of these tubes are bent at an angle of approximately 45 to their front portions and to the remaining tubes. As shown in the drawings, said boiler tubes '1 may extend through the rear wall of the fire box and be connected to a lower header 12 outside andimmediately adjacent the rear wall 19 of the furnace. Said lower header may be connected at its ends by pipes 13 extending either inside or outside of the furnace walls to an upper header 14 Which is "connected bypipes '15 to the rear header or Water leg 3 of the steam boiler. Baffle means 16 consisting for'exa'mpleof'plates or slabs of refractory material indicated at 17 are arranged back of and overlyingahe obliquerportions of water tubes 1 so that said vb aflle means are" supported by such water tubes and are protected by the water tubes to'a large extent from the heat of the combus-' tion chamber. The upper and lowerheaders 14 511C112 may be provided with Ts 18 where they areconnected to the pipes 13 to facili-. tate cleaning of theseheaders, the outeropening ofsaid Ts being plugged'in normal operation.-:&:Suitable blowoif'means 40 may also be 'providedat the ends of the lower header. I The baflle wall 16 cooperateswith the rear wall19 of the furnace to form a pocket 20 for v the collection of ashes,soot, dust,-etc., from" the back passes, and" a' suitable means maybe- 7 provided for permitting access to said, pocket:

1 from, for example an access opening 20 with or; forremoval of collected material th,ere-' door.-22.

The: construction of" the boiler shown in Fig. 5- isisubstantiallythe same" as that above 7 described with ,the exceptionlthat the drum is-located-at the rear of. the boiler setting and; extendstransversely with respect to the tubes andis connected to the front header 2 by means of pipes 23.- I have also shown the short pipes 15 connecting the header 14' to ithe watersleg 3' as bein'gQbent at right angles inthis case','although either the straight or bent 'form'iof connectingypipe is adaptable to either typeof'boiler construction. w

' In the operation of the boilers above de;

tscribedfuel and air are admitted through burner means '7 and combustion; takes place in -'the'combustio'n chamber 6. "It may be noted that'by forming the bridge wallbafile as substantially a continuation-of the bafiie 10 :and carrying it downwardly and rearwardly a larger combustion chamber -:i's provided 1 than is the case in the usu'al type'of construction in which a fire brick bridge wall is pro vided extending vertically downward from -Tthe lowerjend of bafile 10, that is approxi mately from the position of the upper end of: the bridge :wall bafllelG of my invention; By-A-means of 'myimproved' construction a substantially unobstructed combustion chamber isprovid'ed extending from-the frontwall 1 1 of the furnace to the rear wall 19;- The I provision of such'a'large unobstructed'combustionchamber i's of'particular advantagev in connection with the burning of liquid, 7 iga'seous, or powldere'd fuel, as it permits more complete combustion of such fuel therein.

The hot products of combustion pass up. over a the upper edge of bafile 10, down between baffles 10 and 9, and thenceout to the stack outlet 8, giving up their heat to the water tubes in their passage to heat'the water therein. The lower row oftubes 1 are exposed to the mostintense heat and particularly the inclined portions thereof in front of the baffies 16. In addition to heat received directly from the hot gases, these tubes are exposed to radiation of heat from the hot walls of the combustion chamber and .also take up heat received byradiation onto the basis 16' with which such tubes are in contact at their inclined portions. The rapid heating of. the water thusv produced in these tubes causes an extremely good circulation of water therein and not only produces an efiicient utilization of the heat but also prevents deposition of the scale or sediment in the tubes. The

direction of circulationof water is downward in the connecting pipes 13 and upward in the tubes 1. j The tubes 1 being directly connected with the boiler improve the entire circulation therein. I

,7 T he reception of a considerable amount of heat by radiation onto these tubes'cools the combustion chamber-somewhat below the temperature produced in the ordinary type of boiler in whichthecombustion chamber is almostentirely surrounded by fire brick and thus protects, the furnace brickwork.

F urthermore the inclined portions of the tubes 1 serve to protect the brick or refractory plates 1'7 both direct screening action and by taking up heattherefrom. In addition to the above advantageous features the elimination of the fire brick bridge wall now used initselfmateriallv reduces the 'cost'of maintenance ofthe, furnaces.

-Any soot,dust,or ashes collecting above the baflle 10 or the bridge wall bafile 16'settles tothe bottom ofpocketj 20 and may be easily removed from time to time'by removingdoor 22 and cleaning out the collected material through the opening 21. In the ordinary type of" Water tube boiler any solid ma'-- terial deposited in the back passes collects betweenthe tubes and is very difiicultly removed. Byjproviding the lower-most row of tubes,- according to my invention, with,

. portions extending clear" of and below the other :tubes and providing a wall of refractory material on such portions of these tubes, a readily accessible andeasily cleaned pocket is provided between said wall of refractory material and the rear wall "of the furnace,"

into which such deposited"solidmaterial falls andfrom which it may be removed easily;

While Iprefer, for the sake of. convenience and superior construction, to locate the lower header 12 outside the'rear wall of the furnace as above described, it may in some cases be located inside, but immediately adia cent-the lected material.

rear wall, as shown in Fig.6; Insu'ch case the lower-tubes? do not extend through the rear wall but header 12 extends through the side walls for'connection. to nines In order to facilitate the cleaning a metalplate 24 may be provided over the header 12.

i As shownin Figs. 7 and S-the: bridge wall baflie'according to'my invention may also be applied in connection with boilers-of the bent tube type such as the Stirling boiler. The boilershown in these figures comprises the usual steam, water and mud drums 25, 26, 27 and 28 connected in the usual manner by banks of tubes indicated at 29, 30, 31,32 and 33, and provided with the usual means for feeding water thereto and permitting with drawal ofsteam therefrom. Baffle means of suitable refractory material may also be pro vided arranged in any suitable manner for example as indicated at 34,35, 36, 37' and 38, so as to cause the hot combustion gases to passfbetween the tubes in a'circulatory manner, to the stack outlet 8.

According to my invention the lowest row of tubes 29 of the front bank of tubes 29 are continued on down below the lower drum 28 and extend downwardly and rearwardly to a lower header 12 located outside the furnace wiall.. The portion of the tubes 29' below the drum 28 may as shown be in a direct line with the upper portions of these tubes or they may if desired be bent at any suitable angle to such upper portions in order to provide the desired slope, say from to to the horizontal. A bridge wall baffle 16 comprisin for example refractory slabs, plates, or

bricks 17 is provided as before, above and supported by the lower portions of these tubes so as to direct the combustion gases upward and eliminate the necessity for the usual fire brick bridge wall extending vertically downward from drum 28. The lower header 12 is connected as before at its ends by means of pipes 13 to the upper header 14 which is connected by short pipes 15 to the drum 28. I It will also be seen that as before an unobstructed combustion chamber is provided extending between the front and 7 rear walls of the furnace, and the baffle 16 cooperates with the rear furnace wall 19 to form a pocket 20 for the collection of soot, dust and ashes, and opening 21 and door 22 are provided for the removal of such col- The manner of operation of this type of boiler is well understood, including the direction of flow of the hot combustion gases therethrough, and the manner of operation and advantageous features of my invention are substantially the same in this case as in the forms above described.

The invention comprises in any case a row of tubes located below or constituting the lower-most row of a bank of water tubes and "having inclined portions extending rearcated above and supported'by, and preferably:

in direct contact. with said inclined portions of these tubes, said inclined portions: beingthus adapted to receive heat bvradiation from the furnacewalls and lay conduction from said baffle meansas well as from the hot combustiongases themselves, and said bafilemeans beingso disposed as to direct the combustion gases into contact with the bank of water tubes. Furthermore the said inclined portions of the lowermost tubes extend free of the remaining tubes of said bank, and in such a position that a pocket is provided above and behind'said baflle means, for the collection and easy removal of deposited solid material. Also, in all the constructions shown, a large and unobstructed combustionchamber is provided between the front and rear furnace walls, so as to provide ample space below the tubes for the complete combustion of liquid, gaseous, or powdered fuels.

I hereby disclaim so much of the subject matter of invention herein disclosed as is disclosed also in the application with which my orginal patent was in interference, namely, application of J. Coutant, Serial No. 60,435, filed October 5, 1925, for Pulverized fuel combustion, claiming the French filing date of October 7, 1924.

WVh-at I claim is: v

1. In combination with a furnace having walls enclosing a combustion chamber, a

boiler having a plurality of rows of inclined" water tubes above said combustion chamber and connected for circulation of water there-' through, sa'id'tubes extending from a lower rear connecting vessel or header inclinedly upwardly to a higher front connecting vessel or header, and a single supplemental row of said tubes the same having their front ends connected into said higher vessel for circulation in the boiler, and extended first rearwardly below and parallel to the boiler tubes and then having the rear end portions thereof extended downwardly below the boiler from a position adjacent the remaining rows of tubes at a substantial slant to a connecting header in a protected position, and such connecting header, downtake connections from the lower rear vessel feeding water to said connecting header and thereby to the lower rear ends of such extended single row of tubes, wall elements of refractory material associated with said slantingly extended portions of said single row of tubes to form a closed wall wholly below the boiler and bounding the combustion chamber and exposed directly to the rear ot-such: closed wall, and "such closed wall'a nd rearwall cooperating to provide a downwardly extending pocket wholly below the boiler'for collection ofvashes or solid ma- 7 'terial settling from the boiler; with means permitting discharge of material from said pocket and there being in closedrelation to said closedwall an upward baflle extension into the boiler to. form ascending and d escending passes therein. a 2. In combination with a'furnace having I walls enclosing a combustion chamber, a boiler'having a plurality of rows of-incline'd water tubes above said combustion chamber and connected for circulation of water there through, said tubes extending fr'om'a lower rear boiler header inclinedly upwardly to a higher front-boiler header,;and,a single sup,- plemental row ofsaid tubes the same having their front ends connected into said higher header for circulation in theiboiler. and'extended first rearwardly" below and parallel to the boiler tubes and being then bent and the rear end portions thereof extended and moor diverted downwardly below the'boiler i a PQSitiOII'iIItQIIHEdlHtG the ends of the remaining rows of tubes relatively steeply to a connectingheader in a protected position, downtake connections from the'lower rear boiler header feedin ,water to said connect-v ing headerand there y to the lower rear ends of such extended single row of tubes, wall elements of refractory material associated with said steeply-extended portions of said single row of tubes to form a closed wall wholly below the boiler and bounding the combustion chamber and exposeddirectly to the radiant heat therein; a furnace wall to the rear of suchclosed wall and such closed wall and rear, wallc'ooperating to provide a downwardly extendingpocket wholly below theboiler for collection of ashes or solid ma terial settling from theboiler, with means permitting discharge ofmaterial from said pocket, and said closed wall having an' upward bafiie extension into the boiler to form ascending and descending passes therein.

' EDWARD J. FRANKLIN.

Images