US1691934A - Boiler furnace - Google Patents

Description

' E. A. PACKARD BOILER` FURNACE Filed N'ov. 5, 1925 2 Sheets-Sheet l ullllmrl f1/wanton E. A. PACKARD BOILER FURNAGE Nov. 2o, 192s.

Filed Nov. 5, 1925 2 sheets-sheet 2 Patented Nov. 20, 1928.,

UNITED STATES NT oFFicE.. i

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EDWIN A. PACKARDQOF YONKERS, NEW YORK, ASSIGNOR TO INTERNATIONAL COM- BUSTION ENGINEERING CORPORATION, OF NEW YORK, N. Y., A CORPORATION F DELAWARE.

BOILER FURNACE.

Application led November 5, 1925.

This invention relates to boiler-furnaces and it is particularly useful where the fuel is to be burned in finely divided form 1n suspension, as for example, in the form of powderedcoal.

It has recently been proposed 1n pulverized coal burning installations to at one and the same time greatly decrease the size of the boiler as well as of the whole installation and to obtain the same or greater steaming capacity than heretofore obtained in what would be corresponding standard constructions.

In accordance with such arrangement, it

has been proposed to practically deinethe combustion space with the tubes of the boiler,

i. e. to provide a furnace shaped boiler within which the fuel is burned so that the tubes of the boiler are subjected to radiant heat,

the amount of work done by convection being relatively small'. The tubes deiining the upright sides of the combustion space, according to such proposal, have been provided with longitudinally extending fins so as to provide in eii'ect continuous water walls.

In such arrangement, however, the width of the ns must be comparatively narrow in order to prevent the edges of the fins from burning oil' and consequently the tubes must be relatively closely space altho they are more widely spaced than if no lins were employed.

According to one phase of my invention, I propose to obtain the advantages -of the water wall construction described, while at the same time making it possible to decrease the number of tubes and to increase the width of the fins employed.

Another of the advantages of the general construction previously described is that the extensive and heavy refractory side walls are eliminated for the reason that the water walls themselves define the boundaries of the combustion space, comparatively light sheathings to prevent radiation to the eX- terior being substantially all that is required in place of the usual refractory walls.

As to this phase of my invention I propose to obtain these advantages by employling a novel arrangement of tubes to be more particularly hereinafter described.

The foregoing, together with such other objects as may hereinafter appear, or are incident to my invention, I obtain by means Serial No. 66,929.

of a construction illustrated in preferred form in the accompanying drawings wherein,

Fig. 1 is a vertical section thru a boilerfurnace installation embodying Iny invention;

Fig. 2 is a diagrammaticview illustrating a modiiicationof my invention;

Fig. 3 is a fragmentary sectional view illustrating a detail of the arrangement of Fig. 2, and i Figs. 4 and 5 are sectional views illustrating a different manner of ring the fuel from that shown in Fig. 1, Fig. 4 being a section taken on the line l4 4 of Fig. 5.

Referring now to Fig. 1, the reference character A denotes the combustion space of the'boiler-furnace. Four upright water walls define the four upright sides of the furnace, such Vwalls being composed of tubes 7 provided with the longitudinally extending fins 8 previously described. The tubes 7 constituting the front water wall have their ends connected in the upper drum 9 and the lower drum 10, and the tubes 7 of the rear water wall have their ends connected to the drums 11 and 12 respectively. The drum 12 lies above the level of the drum 10 and the drum 11 lies above the level of the drum 9. The ktubes 7 of the side water walls have their upper ends connected into the header 13 and their lower ends connected into the header 14, the headers 13 connecting with the drum 11 and headers 14 connecting with the drum 10. Suciently large downcomer tubes 15 connect the drum 11 with the drum 10. The top of the combustion space is defined by a water wall c composed of tubes 16 provided with fins 17 as above. A number of inclined tubes 18 extending from the drum 10 to the drum 12, define the bottom of the combustion space, such tubes being spaced sufficiently far apart to permit the refuse to freely gravitate therefrom into the' ash space 19 therebelow.

The upright water walls described are closed by a sheathing 20, and a similar sheathing 21 is carried by the tubes 16. The ash hopper 19 closes the bottom of the furnace, the ofl'take 21 for the waste gases of combustion leading from the space dened by the hopper.

The tubes 7 and the tubes 16 are relatively widely spaced apart and the fins carried thereby are correspondingly wide (see for example Fig. 4). ln the absence of provision to the contrary the edges of the fins would be burned off because the width of the fins is preferably so great that heat cannot be conducted into the tubes from the edges with sutiieient rapidity to prevent such edges from burning. I, therefore, provide in front of each of the side water walls and below the top water wall, boiler tubes which are staggered with reference to the tubes constituting the side and the top water Walls so as to come opposite the edges of adjacent tins, thereby shading the tins and shielding them from the direct radiant heat. The shading tubes for the upright walls are indicated at 22. The shading tubes for the front and rear water walls are connected respectively to the drums 9 and 1.0 and the drums 11 and l2, While the shading tubes for the side water walls are connected to the headers 13 and 14. The shading tubes 23 for the upper water wall are connected to the drums l1 and 9.

It will be seen from the foregoing that circulation is established from the drum 1l to the drum l0 and thence upwardly thru all of the tubes described back thru the drum ll. The tubes constituting the water walls and the shading tubes as well are all subject to radiant heat and, therefore, heat is transmitted at a very high rate and a very small boiler can be employed to produce a very large quantity of steam. By virtue of the employnient of the shaded tubes the water wall tubes can be Widely spaced apart and large fins may be employed Without encountering the difficulty of burning oil' and thus a practically continuous metallic Wall can be employed. Also, if desired, the fins may be dispensed with by virtue of the employment of the shading tubes, because the shading tubes'in such case Would shade that portion of the sheathing not directly covered by the tubes of the Water walls.

Steam from the drum 1l is led thru the super-heater 24 located in the bottom of the olftake 21 and the air heater B is located in such otl'take immediately above the super* heater elements.

The gases leaving the combustion space defined by the radiant heat tubes is at a very high temperature, `much higher than usual, in order that a high degree of preheated air may be obtained in the air preheater. This highly heated air is used for combustion and is taken from the heater by the ducts 25 leading to the burners 26 located at the four corners of the combustion space, preferably near the upper portion thereof. These burners discharge into the corners in a manner to produce vortical'mixture and combustion, the combustion being intense and turbulent, whereby a high llame temperature and short length of flame travel is obtained.

Referringnow to Figs. 2 and 3, I have being connected to the drum 3l by downcomers 32, While the upper portion of the next header is connected by upcomers itil to the drum 34, downcomers connecting the lower-most of the upper part of headers to the drum 31 and upcomcrs 3G connecting the upper of the two higher headers to the drum 34, Tubes 37 connect the two drums 3l and 34. It is obvious that the ar rangement of Figs. 2 and 3 may be employed with fuels otherv than pulverized coal.

Referring now to the arrangement of Figs. 4 and 5, the burners88, in this rase, extend downwardly thru an arch Bt) supported on tubes 4() constituting an outer water Wall. Certain of such tubes are formed so as to shade the edges oi the burner casting, the tins being interrupted for this purpose. The object of so shading the. burner casting is to prevent burning thereof, particularly where intense turbulent combustion is employed.

What I claim is:

l. In a boiler furnace, water walls delining combustion space and comprising tubes having longitudinal fins of such width that in normal operation of the furnace a portion thereof would burn off and means shading said tins to prevent such burning off.

2. In a boiler furnace, Water walls delining combustion space and comprising tubes having longitudinal fins of such Width that in normal operation of the furnace a por- Ition thereof would burn off and other tubes also subject to radiant heat spafjed inwardly from said first tubes and coming opposite the fins to prevent such burning ott'.

3. In a boiler furnace, water walls detining combustion space and comprising tubes having longitudinal tins of such width that. in normal operation of the furnace the heat absorbed by said tins could not be conducted to the said tubes rapidly enough to prevent burning off of said fins, and other tubes also subject to radiant heat spaced inwardly from said first tubes and coming oppositie the said tins to prevent such burning oil'.

In testimony whereof, I have hereunto signed myname.

EDWIN A. PACKARD.

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