US1434878A - Hot-blast stove - Google Patents

Description

A. N. DIEH'L,

HOT BLAST STOVE.

I APPLICATION FILED AUG-8,1921. 1,434,878, Patented NOV.I 7, 1922!.

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A. N. DIEHL. HOT BLAST STOVE.

APPLICATION FILED AUG.8, 192|.

Patented Nov. 7, 19,22.

4 SHEETS-SHEET 3 Patented Nev. '7, 1922.

STATES Hor-BLAST s'rovn.

Application filed August 8, 1921.

To all w wm t may concern:

Be it known that I, AMBRosn N. DIEHL, a

citizen of the United States, and resident of Duquesne, in the county of Allegheny and State of Pennsylvania7 have invented certain new and useful Improvements in Hot- Blast Stoves, of which the following is a specification.

My invention relates to the construction of hot blast stoves employed in heating the air used in blast furnaces, and while not limited thereto, the invention relates more particularly to the construction of the top of a two-pass stove ot the central combustion chamber type.

In such stoves the cylindrical plate metal shell is lined with refractory material and is provided with checker-work formed of fire brick or similar refractory material. In using the stoves the refractory walls torming the channels or passages in the checkerwork are heated to a high temperature by burning gases in the central combustion chamber and causing the burned gases or products of combustion to pass through the passages in the checker-work in the travel thereof to the stack through which the products of combustion are led trom the stoves. After each 'heating operation the cold blast, or air under considerable pressure, is passed into and through the stove and is heated kby contact of the air with the surfaces of lthe highly heated checker-work.

In stoves of this type as constructed heretofore, the products of combustion, in the passage thereof through the stove, form an annular dead space or pocket of still gases immediately above the upper 'end of the vchecker-work, and the lpresence of this pocket of still gases causes an uneven distribution o't' the products of combustion Vwithin the distributing chamber above the upper end of the checkerwork. The result `has been that the vertical passages in the checker-work ad- Ajacent to the outer wall or lining of the stovesand the annular row of passages in the checker-work adjacent to thewalls forming fthe central combustion chamber, receive "the `major portion of the products of combustion, while the intermediate annular rows of passages inthe checker-work,.or those immediately vbeneath lthe pocket, `receive little or "none oi. them.

One object of invention is `the provision in-'a 'hot blaststove yoi novel fmean's Serial No. 490,527.

whereby the formation of such pockets of still gases within the distribution chamber is avoided and overcome, the burned gases or products of combustion are uniformly distributed over the top oi' the checker-work and are caused to How through all oi'l the passages in the series of rows `of vertical passages within the checker-work and the thermal etiiciency of the stove is materially increased.

Another object ot' the invention is the provision in a hot blast stove of novel means for distributing and directing the flow of the burned gases into the series of rows orn vertical passages in the checker-worlr of the stove that may readily be applied to existing stove structures without material changes in the stove structure.

Referring now tothe drawings forming part of this specification, Figure l is a vertical sectional elevation, partly broken away, showing a hot blast stove having my invention applied thereto.

Figure 2 is a sectional plan oi" the apparatus of Figure l, the section being taken on the line H-Il oic Figure l.

Figure 3 is a similar sectional plan taken on the line III-HI oit' Figure l.

Figures 4t and 5 are anemometer charts showing the results obtained before and after the application of my invention to a hot blast stove, in a series oi tests made for that purpose. 4

Figure 6 is a vertical section of the upper end of a `hot blast stove of the usual construction illustrating the way in which the dead spaces or pockets torni above the upper end of the checker-work and the resulting unequal distribution o the products ci' combustion within the distribution chamber and into the vertical passages formed by the checker-work.

Figure 71is 'a similar vertical section illustrating the way the annular dead spaces or k'pockets yare eliminated and the iiow oft the products of combustion is directed within the distribution chamber so as yto supply the products of combustion to all of the vertical passages formed bythe checker-work within the stoves embodying my invention.

`Inrthe accompanying drawings, the numeral .2 `designates themetal shell ofahot blast stove :having a vcentral `combustion chamber f3, and :being provided with the usual cold :blast inlet @stack l5,;and stack'valve 6. The

stack 5 and cold blast inlet 4 open into the passage 7, which in turn opens into the outer end of the horizontal flue 8. The flue 8, which is located below the bottom of the stove, has its inner end connected with the vertical flue 10, which extends upwardly into the chamber 11 in the bottom of the stove, this Chamber being on the axial center of the stove.

An annular wall 12 forms the combustion chamber 3, and a second annular wall 13 forms the outer wall or lining of the stove. The space between the wall 12 and wall or lining 13 forms an annular lengthwise Vertical chamber which contains the stove checker-work. This checker-work as shown comprises a series of radial walls 14 and intersecting series of annular walls 15, forming a multiplicity of lengthwise vertical passages 16, through which the products of combustion pass downwardly in heating the stove checker-work.

The vertical passages 16 open into the distributing chamber 17 which is located at the top of the stove above the upper end of the checker-work, this chamber 17 having a dome-shaped refractory lining 18 which is supported on and built integral with the refractory lining or sidewall 13. The passages 16 are in open communication with the upper end of the combustion chamber 3, through the medium of the distrib'- uting chamber 17 so that the products of combustion pass from the combustion chamber, through the distributing chamber 17., into the vertical passages 16 and, after traversing the vertical passages 16, emerge into the chambers 22, and pass through the radial passages 21 into the chamber 1 1, and thence out of the stove by way of passages 10 and 8 into the stack 5. the stack valve 6 being open at such time.

The combustion chamber is provided. with a refractory bottom 19 which is spaced some distance above the bottom 2O of the stove and forms a top or roof for the chamber 11. The stove is provided with the usual complement of gas and air inlets, relief valves and other necessary appliances These not forming part of this invention are not shown and will not be further described.

In stoves of this type as constructed heretofore, the products of combustion flowing out of the combustion chamber 3 into the distributing chamber 17 impinge against the top or roof 18 of the stove and, due to centrifugal force and other natural and artificial forces, are held close to the roof 18 and directed toward the outer wall or side of the stove. This results in the major portion of the products of combustion entering the passages 16 nearest to the side 13 of the stove and some of the products of combustion enter the passages 16 nearest rases/s the wall forming the central combustion chamber'. A considerable portion of the passages, (those located midway between the wall 12 and wall 13) receive little or none of the gases. lStated another way, an annular pocket or dead space filled with still or inert gases forms immediately above the upper end of the checker-work, with the result that the entering products of combustion form currents and flow into the annular rows ofpassages in the checkerworlr closest to the store side wall 13 and to the annular wall 12, and do not to any extent flow into the intermediate rows of passages. (See Figure 6).

In order to avoid and prevent the formation of the annular dead space or pocket in the distribution chamber 17 and in order to cause the products of combustion to be uniformly distributed over the entire area above the checker-work, an annular deflecting ring or baflie 23, having'converging upper and lower faces 24 and 25 respectively, is provided within the distribution chamber 17 on the wall 13 of the stove at a point immediately above the upper end of the checker-work.

In the operation of stoves equipped with my invention, the products of combustion emerge from the combustion chamber 3 into the distribution chamber 17 impinging upon the roof 18 of the distribution chamber l17 and lflowing loutward toward the outer wall 13 of the stove. The flowing products of combustion, upon striking the inclined surface 24 of the deflecting ring o-r baffle 23, are retarded and deflected inwardly toward the vertical. center of the stove. In this way the dead space usually occupied by the still gases or products of combustion is eliminated and the flowing gases are directed into the upper ends of the intermediate rowsy of passages in the checker-work, as well as into those adjacent tothe periphery of the stove and to the inner series of passages next to the wall 12 forming the central combustion cha-mber. The uniform distribution resulting from the use of the deiector ring or baflie 23 will be readily seen by comparing Figures 4 and 5 and by reference to Figures 6 and 7 In Figures 4 and 5, in which the lines 26 and 27 designate the walls defining the transverse dimensions of the passa-ges 16 of the checker-work, the numerals within each space represent the relative velocities in feet per minute at which Vthe products of combustion flow through the multiplicity 0f passages 16. In Figure 4 it is shown that without the use of the deflector ring or baille 23, the outer three annular rows of passages 16 receive most of the products of combustion, while the amount of products of combustion entering the next three annu- 1 ,assess lar rows is practically Zero, and that the innermost annular row of passages received less than either of the outer three rows. The cause of this effect is illustrated in Figure 6.

By reference to Figures 5 and 7, it will be seen that in stoves equipped with my invention, the products of combustion are uniformly distributed over the area immediately above the checker-work within the distribution chamber 17, and that each of the annular rows of vertical passages 16 of the checker-work receives practically the same volume of the highly heated gases, with the result that all of the passa fYes are uniformly heated and, each of the passages is heated so as to perform its part of the worlr in heating the cold air afterward passed therethrough to form the hot blast for the blast furnace.

While a preferred embodiment of my invention isy shown herein, the invention is not to be limited thereto, since various modifica.- tions thereof may be made without departing from my invention as defined in the appended claims.

I claim l. The combination with a hot blast stove having' the usual. outer wall, central combustion chamber and intermediate checker-work. of means spaced above and independent of said checker-work for directing the flow of products of combustion from said combustion chamber, said means being adapted to effect a substantially even distribution of' the products of combustion within the passages of said checker-work.

2. The combination with a hot blast stove having the usual outer wall, central combustion chamber and intermediate checkerwork, of a baffle ring above said checkerwork for directing the flow of products of combustion from said combustion chamber, said baflie ring being constructed and arranged to effect a substantially uniform distribution of the products of combustion within the passages of said checker-work.

3. In a. hot blast stove having the usual outer wall and dome-shaped top, the combinat-ion of a central combustion chamber, checker-work surrounding said combustion chamber, said checker-work forming a multiplicity of lengthwise vertical passages connected with the combustion chamber at the upper end of the stove, and an annular defledtor on the inner face of said outer wall above the upper end of said checker-work, said defiector being adapted to direct the liow of products of combustion above the upper en d of said-checker-work, and thereby cause a substantially uniform distribution of the products of combustion within the passages of said checker-work.

si. ln a hot blast stove having the usual outer wall and dome-shaped top, ther combination of a central combustion chamber, checker-work surrounding said combustion chamber, said checker-work forming a multiplicity of lengthwise vertical passages connected with the combustion chamber at the upper end of the stove, and an annular deflector ring on the inner face of said outer Wall, said deflector ring being positioned adjacent to the juncture of said dome-shaped top with said outer wall and extending into the iiow path of the products of combustion, to thereby interrupt and deflect the flow of said products of combustion and cause a uniform distribution thereof within the passages of said checker-work.

' 5. lThe combination with a hot blast stove having the usual outer wall, central combustion chamber, and intermediate checkerwork, of a baille ring on the inner surface of said outer wall above the upper end of said checker-work, said baille ring having inclined sides adapted to distribute the products of combustion above the upper end of said checker-work and thereby cause a substantially uniform distribution of said products of combustion into the passages in said checker-work.

6. The combination with a hot blast stove having the usual outer wall, central combustion. chamber. and annular set of vertical dues, of means for retarding the flow of products of combustion along said outer wall.

7. The combination with a hot blast stove having the usual outer wall, central combustion chamber', intermediate checker-Work and distribution chamber above said checker-work, of means within said distributing chamber for directing the flow of products of combustion into the passages of said checker-work to thereby uniformly distribute said products of combustion within the plurality of rows of passages in the c ieclrer-work.

ln testimony whereof, l have hereunto set my hand.

AMBROSE N. DlEl-L.

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