US1970500A - Boiler construction - Google Patents

Description

3 Sheets-Sheet l A. J. DONOHUE BOILER CONSTRUCTION Filed Jan. 31, 1933 Aug. 14, 1934.

211 6 6' Maw W 3 Sheets-Sheet 3 A. J. DONOHUE BOILER CONSTRUCTION Filed Jan. 51, 1935 Aug. 14, 1934..

Patented Aug. 14, 1934 UNITED STATES PATENT-orifice BOILER CONSTRUCTION Anthony J. Donohue, Philadelphia, Pa., assignr to Simplex Gas Products Corporation, Phlli delphia, Pa., a corporation of Delaware Application January 31, 1933, Serial No. 854,508 11 Claims. (01. 123-210) This invention relates to improvements in fluid- Abruptly changing the direction of flow of the fuel-fired heating apparatus. This class of apgases by the use of baiiies or staggered flue pasparatus is now subject tostringent laboratory apsages tends to eliminate stratification and proproval tests to insure the user safety from carbon mote scrubbing of the hot gases a a t the heatmonoxide poisoning, To t these approval ing surfaces. Such means, however, reduce the 69 tests with heat absorbing structures heretofore capacity of the heating unit due to thehigh reused, over-ventilation and higher stack temperais e y imPOSe O the flowing 848368, with tures than necessary are resorted to in order to the result that larger amounts of heating surface achieve high capacities without the formation of are necessary, lee-ding t umbe o e units in a carbon monoxide. This practice, obviously, reattempt to. produce complete combustion at any suits in lower operating efilciencies. definite capacity. 1 1 f The transfer of heat in apparatus of the class An important object of the present invention described, especially when using the usual type is the provision of a structure of this character of Bunsen burners in a gas-fired boiler can be in whi h the fl w y are se' onstructed that an best effected by convection, for under the most i r f m l ar impingement! is Produced favorable conditions, less than 15 per cent. of the without imposing any appreciable resistance total heat in the fuel will be transmitted from upon the convectionalflow of the hot gasesthe flame to the heat-absorbing surfaces of the A further object 01 the-i v n i t p v boiler by radiation. Some additional heat will be an efficient absorbing structure vcapable of operradiated from the carbon dioxide and water vast ng at high capacities with low stack tempera- 7 por molecules in the hot gases, but this amount tures and a minimum amount ofexcess air withis'negligibie due to the thin streams of gases used out the formation of carbon monoxide. in order to promote the maximum heat transfer A further object of the invention is the proviby convection. The quantity of heat transmit- -Bi0n of a novel and imp v x nded Surface ted by convection per unit of heat-absorbing area Projection and method of arranging such surface 80 depends primarily on the number of molecular pr j c i n up n h w lls to increase the heatimpingements of the hot flowing gases against ins p y theIeOfthe heat absorbing surfaces. Increasing th Astill further object is to provide improved exnumber of molecular lmpingements against the lir a Pr je tions arranged to substanheating surfaces or decreasing the temperature tially prevent 8.11 undesirable flOW Of gases to the 85 gradient across the gas stream by increasing the exits through uninterrupted inclined P e-8 8- number of impingements of hotter molecules These and other Objects I attain y e 00 against layers of cooler molecules near the heat striletioi'i Shown in the mp nying drawin ing surface increases the rate of heat transfer. wherein, for h p p f illustration, I h v The molecules of hot flowing gases, unl .shown a preferred embodiment of my invention to strained, tend to stratify in layers of varying temehd wherein; peratures generally parallel to the direction of 1 is vertieel Se ie dl View through a flow with the hottest layersoi molecules in the boiler constructed i a c rda ce wit my inve center or core of the stream. Due to their kinetic tioh;

co energy, the molecules vibrate within the flowi a similar enlarged sectional view us ing layers of the gas stream, colliding repeatedly through di e et ehs ii ll t e t e ellwith adjacent molecules at a speed dependent Striietieh 0f the fi W;

upon their temperature. The slower moving d- 3 is mde fragmentary ec molecules of the cooler layers are next to the th u h ne oi'the duewuys on linedf Fid- 4 cs heat-absorbing surfaces, and the more rapidly F dt is i Side v -On of @he of the flectiehs, 1

vibrating molecules and hotter layers towards the the Surface projections of the boiler being parcenter of the streaming gases. This results in a tiail i d; temperature gradient across the gas stream i 5 is a Section on i H Oi F d- 3 which is especially steep near the heat-absorb- Fig. 6 is a section on line 6-6 of Fig. 3; and

to lug surface. The sharp drop near the heat-ab- Fig. 'l is an enlarged detail elevation showing llltl sorbing surface has lead many investigators to the surface projections.

i believe that a so-called dead film or layer of Referring now more particularly to the drawinactive gas adheres to the heating surface and ings, the numeral 10 generally designates a suitthat this layer or film acts as a heat insulation able casing having arranged therein end sections to retard the flow of heat. ll and a center section 12, each of said sections Rm I ll and 12 having it water leg 13 extending to the bottom of the burner pit 14 of the boiler. Connecting the upper ends of each end section ll and the center section 12 is a stack outlet 15, and arranged between each end section and the center section is one or more intermediate sections 16. Suitable intake and flow connections between the sections ll, 12 and 16 are provided, as indicated on Fig. 4 of the drawings. Each of the ections 11, 12 and i6 is narrowed at its lower end to produce a tapering introducing throat I! for riueways 18 between the sections and each or" the sections has its side wall of slightly sinuous or zigzag formation with the peaks 19 of the angle between adjacent singularly related laces aligned with similar portions or the adjacent or oppose section, with the result that a vertical series oi fentnriform flueway sections are provided. The throats 28 of these Venturi-forin flueway sections decreose in width from bottom to the top of the i'iuewey so that compensation is had for the contraction of the es a result of reduction of temperature thereof.

he fenturl shape of iineways tends to direct a considerable the flowing gases nor mally flowing in the center oi the flneway toward the nest-sheer" r crraces, due to the feet that s s the Ventin'i action. tends to screed i e out through the user.

werdly 2c. is the flowing es to v S ll? he should I y ice; neg,

. .l' e y rticel i: men's street is to attained. ventin'i with relativeangles and l .1 street c cy to ones lg oi the sec at the Venti i' throats. Vent action further minimizes and exit ence to t? flowing gases, espe fluevioys, cons w .ile constantly varying in width, ere neither tort-none nor sinuous, so the resistance set unloy t e ilnewey wells is reduced to a r.- nails on ports 2]. lfillliicti in termediete sections it permitting transmission oi gases adjacent finetvays of the unit of the boiler and will serve to tether eliminate any 'enclency to chokino'. These ports are, pref= located at the junction of the Venturi se tlons,

Having increased the number or heat molecules directed against the Wells oil the fineweys, an all r 'tional amount of heating surface per unit area must be provided to absorb the increased heat rendered available. To this end, I provide adjacent faces of the sections 11, i2 and 16 with erotended surface projections 22. Such surface pro jections, where provided in a construction of this character, should be of a construction nroviding a relatively large heat=absorhing surface without imposing appreciable resistance to the passage of the flowing gases. Furthermore, the projections should be so arranged that resistance to flow re snltim; from the arrangement is minimized without the f rmation or direct passages either vertirev eoo rnodiztiecl slip-stream formation, each comprising a main body portion 23 and an elongated tall portion 24. The tail portion is reduced in thickness in relation to the main body portion and extends from the main body portion in the desired direction of flow of the gases; in the present instance, vertically. The main body portion 23 or the pin presents slightly singularly related upstream surfaces 25 which divide the gas stream and direct the divided stream to the rounded side surfaces 26 of the body. l'he tail portion serves, as in all slipstream constructions, to prevent the formation of dead air pockets at the down-streero face of the pin and being elongated ots likewise as a straightening vane directing the the desired vertical direction, thereby substantially preventing a short circuiting fiovv of em in an inclined plane to the fiueway exits. For practical reasons, the upper end portions of the tails 24 preferably decreased in height as i dicated et 24-41, connection of these low portions with the pin pro enting e, relatively ly or: erdly end downwardly sloping" sur to avoid the collection or foreign rtien, the sin-faces of he toil meet at e reen ant s ngle,

i t the genes engaging the tail portion most or e their direction to a certain erne t. This ce s sli check in the moveend a ther i oningement oi es the surfaces oi ti pins. The ortions are of such width that no truly vertical gas prem ses are provided between pins, end tail portions 2% ere oi such length that diagonally vertical posse-gee ere sulcstantieily interrogate-cl.

AS neerly as can be determined, the noes-age oi the gases is as indicated by the sorrows of his. 5. Particular importance is attached to the fact that the pin arrangement leaves no uninterrupted vertical passages and substantially no inclined passageways through which hot asses may escape to the outlets. Pins on c oosing sides of the fluency are preferably arranged in stag Employing the construction herein disclosed, it is possible to operate apparatus of the class described, utilizing balanced draft only, at capacities slightly greater than one-quarter boiler horse power per square foot of flue-way surface while lowering the temperature of the flowing gases from approximately 2000 degrees F. at the point of entrance to the flueways to only 300 degrees F. at the stack outlet, showing a high ratio of heat transfer at high operating capacity. Further, the gases are discharged at this temperature free of carbon monoxide and with an unusually low percentage of excess air.

Since the construction illustrated is, obviously, capable of considerable modification without in any manner departing from the spirit of my invention, I do not wish to be understood as limiting myself thereto except as hereinafter claimed.

I claim:

1. In a boiler, a fiueway the walls of which are provided with substantially horizontal rows of surface projections, the projections of one row being staggered with relation to those of the next row, said surface projections being streamlined in the direction of flow of gases in the flueway, the rowsof projections at opposite sides of the flueway being staggered with relation to one another.

2. In a boiler, a flueway the walls of which are provided with substantially horizontal rows of surface projections, the projections of onerow being staggered with relation to those of the next row, saidsurface projections being streamlined in the direction of flow of gases in the flueway, the tail portions of the projections of each row directing gases against the sides of the body portions of the projectionsof the succeeding row, the rows of projections at opposite sides of the flueway being staggered with relation to one another.

3. A flueway wall provided with surface projections, each surface projection comprising a body portion and a tail, said body portion being of generally ovate cross section with its longer axis transverse to the general line of gas movement through the flueway, the tail portion being relatively narrow and extending in the direction of movement of the gases.

4. A flueway wall provided with surface projections, each surface projection comprising a main body portion elongated tail portion of abruptly reduced width with respect to the body portion and curvilinearly joined to the body portion, said tail portion extending in the direction of flow of the gases in the 5. A flueway wall provided with surface projections, each surface projection comprising a main body portion having rounded sides and an elongated ta l portion of abruptly reduced width with respect to the body portion and curvilinearly joined to the body portion, said tail portion extending in the direction of flow of the gases in the flueway and being of reduced height with respect to said body portion.

6. In a boiler, a flueway having surface projections upon the jections each comprising a main body portion having rounded sides and an walls thereof, said surface pro- 7. In a boiler, a flueway having surface projections upon the walls thereof, said surface projections each comprising a main body portion having rounded sides and an elongated tail portion of abruptly reduced thickness with respect to said body portion and curvilinearly joined thereto, said tail portion projecting in the direction of flow of gases in the flueway, said projections being arranged in rows, the rows of projections at opposite sides of the flueway being staggered with relation to one another, the projections of adjacent rows at being staggered with relation to oneanother, the tail portions of said projections being reduced in height with respect to the body portion.

8. A flueway wall provided with surface projections, each surface projection comprising a body portion and a tail, said body portion being of generally ovate cross section with its longer axis transverse to the general line of gas movement through the flueway, the tail portion being relatively narrow and extending in the direction of movement of the gases, the tail portion being curvilinearly merged with the body portion.

9. A flueway wall provided with surface projections, each surface projection comprising a body portion and a tail, said body portion being of generally ovate cross section with its longer axis transverse to the general line of gas movement through the flueway, the tail portion being relatively narrow and extending in the direction of movement of the gases, the tail portion being curvilinearly merged with the body portion and being of reduced height with respect to the body portion.

10. In a boiler, a straight vertical flueway hav ing surface projections upon the walls thereof, said surface projections each comprising a main body portion having rounded sides and an elongated tail portion of abruptly reduced thickness with respect to said body portion and curvilinearly joined thereto, said tailportion projecting in the direction of flow of gases in the flueway and a burner arranged beneath said flueway.

11. In a boiler, a straight vertical flueway the wall of which is provided with surface projections, said surface projections each comprising a body portion and a tail, said body portion being of generally ovate cross section with its longer axis transverse to the general line, of gas movement through the flueway, the tail portion being relatively narrow and extending in the direction of movement of the gases, the tail portion being curvilinearly merged with the body portion, and a burner beneath said flueway.

. ANTHONY J. DONOHUE.

the same side of the flueway

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