US1847710A - Furnace - Google Patents

Description

Mardi 1, 1932. H. A. BRASSERT ET AL 1,847,710

FURNACE Filed Oct. 9, 1929 3 Sheets-Sheet l March l, 1932- H. A. BRAssERT ET AL 1,847,710

FURNACE 3 Sheets-Sheet 2 Filed Oct. 9, 1929 March l, 1932. H. A. BRAssERT ET AL 1,847,710

` FURNACE Filed oct. 9, 1929 s sheets-sheet 3 y jg.

Patented Mar. l, 1932 UNITED STATES PATENT AOFFICEy HERMAN A RRAssERT, SELWYNR P. XINNEY, AND HARRY I). WR'IHERBRR, or CHICAGO,

ILLINOIS, AssIGNoRs 'ro H. A. isRAssRR'r a COMPANY, oF CHICAGO, ILLINOIS, A

FUR-NACE Application led October 9, 1929. Serial No. 398,302.

This invention relates to ,a new and im.-

proved furnace of the vertical shaft type, and

more particularly to an improvement in the upper portion of furnaces of this character especiallyy adapted for use 'as blast furnaces for the production of pig iron. p v

During the past twenty years the trend of `blast furnace design has been more and more to increase "the diameter of the hearth of the furnace and at the same time to steepen the bosh angle and lower the height of the bosh. The result has beenthat blastfurnaces today are much'larger at the bottom than at the top. It will readilyy be seen that when the optimum wind is blown to'correspond to this greater increase'in hearthv area,`that the'velocity of the gases at the top of the furnace is very great, and in some cases twice of what it used to be when the furnace hearthl was not materially larger than 'the top area, and consequently only a half of the Wind volume blown. The difculty in regard to increasing the topl dimensions tocorres'pond with the increased hearth dimensions has been that it isnot possible to obtaingo'odJ distribution when discharging the raw materials from .a large bell into the furnace, unless the-distance between the large bell and thefurnace wall is kept within comparatively narrow limits. 'Itis also not desirable to use too large a bell because with a larger bell the depression of the stock below the bell becomes too pronounced, resulting in the coarse materials rolling into this depression and causing irregularity in the distribution of coarse and fines, and in turn a very` porous'colum-n in the center of the shaft. v

We propose to overcome these ditliculties by`laring out the -linesof the blast furnace at the top. In this way we are able to maintain the most desirable batter ofthe furnace inwall, which is required in order to have a free working furnace and yet to have a stock line area of such proportions that the velocity of the gases at the top is very considerably reduced. Al/Ve have ascertained that within the layers of material nearest to the top, called stock line, the pressure drop per vertical foot lof stock drops faster than in the sections bev low, indicating a greater resistance to gas flow in the uppermost area. By wideninvr out the top section this resistance is decreased and the speed of the flow of the gases. is reduced. Furthermore, with this design a larger size Ibell can beused without detriment, as thein- ,.verted batter will cause the materials to close in toward the center, thereby tending to fill up the depression under the big bell. This rearrangement of materials will cause a cross mixing of the materials deposited next to the wall with those which will have rolled' into\ the center. A further advantage of the reduced speed of the gases near the top of the furnace is that less flue dust will be produced in this section and that flue dust which has been generated Vin lower sections will tend to deposit in the -u pper section, thereby. greatly reducing the amount of flue dust produced. The cross mixing of the stock will afford a better'contact between the gases and the solids, and Will result in a saving` of fuel, the advantage' of which is self-evident. `The importance of reducing ilue dust losses is equally" evident and is a matter of increasing importance with the In both cases the length of timeof contact between gases and` solids is increased.' If this is done by increased height, therblast .pressure is inc eased, resulting ina great expenditure for powerY in blowing and more p ing the furnace higherforby making it wider.

costly construction of the furnaceand wastage lgf energy yin hoisting the materials to the top. Furthermore, with an increased velocity .of gases through the furnace by means of an increased'height'of the descent of the charges the abrasion withinthe furnace is increased. The coke is partially destroyed by a reductionof size before it reaches the hearth, resulting in the well known diilicul'- ties of operation..

With our type of furnace the same factor v of time is secured with a decrease in 'pressure, a-decrease 1n height of stock column,

.with a decreased tendency of-channeling which is generally caused by. too hi'gh a velocity in certain sections of the column.

Another advantage we claim for our invention is that the inverted batter in the top will protect the stock line due to the fact that the st'ock will 'lie close -to the wall, the fines protecting the lining against abrasion and the stock line armament, which enerally consists of cast iron or steel mer-n ers embedded in the brick work, will not be s o apt to fallout due to undercutting of. the

. brick work. Furthermore7 with .our designof furnace the'hightemperature gases will this upper portion of the brick work to the'4 3.5 metal shell so that stresses occurring in both the brick .work andshell are minimized and the brick work is .held in placeagainst the Y shell.

We have also provided a construction '1 0 wherein the brick work in the uppermost portion of the furnace may be supportedby the shell independently of the brick wor in the main body of the furnace. This uppermostbrick work is thereby not affected' b 4Iany vertical movement of the --main bric work. It is an object ofv the presentfinvention to provide a new and` improved vertical shaft "furnace andmore particularly to provide a 5{"'n'ew and improved upper construction for such a furnace. j It is. an additional object to provide a furnace whereinthe quantity of flueodust produced and carried off from the furnace is reducedv and' wherein the gas velocities in the uppermost/portion yof the furnace are rel duced. v

.It is a further object to provide a construction in which the materials charged to 5 0 thefurnace are more uniformlydistributed throughoift the furnace area than in customary furnace construction, and in which 'a better distribution is had of the ascending gases among the descendin materials. It is also an object to provi e a construc- 'bodiments of our invention in the accomline -5-'5y of Figure 4 and 'and a substantially cylindrical shaft portion 'most portion of the furnace is supported bv the shell independently of the lower brick Other and further objects-will appear as the description. proceeds.

We have illustrated certain'preferred empanying drawings, in Which- Figures -1, 2'and 3 are somewhat dia rammatic showings of different forms o furnaces; Y.

Figure 4 is a section on an enlarged scale of the upper portion of the furnace constructedaccording to our invention; Figurev 5 is a fragmentary section taken on shown on an enlarged scale; and

Figure 6 is a fragmentary vertical section of part of Figure-4 on an enlarged scale.

Referring irst to the forms o ffconstruction shown in Figures 1, 2-and 3, in Figure 1 a furnace is' outlined having a hearth portion 11, an outwardly flaring bosh portion `12,

van inwardly inclined f-rusto-conical shaft portion 13, and anoutwardly flaring uppermost portion '14. The portion 14 is shown as rounded and the junction at 15 between the portions 13 and 14 is also rounded. The 10 charging bell is shown at 16. In Figure 2 a furnace is vshown having a hearth portion 17, a Haring bosh=portion 18,

19. The uppermost portion 20 inclines out- 105 .wardly and isin the form of an inverted frustrum of a cone. The portion20 joinszthe portion 19 on line 21. The charging bell is v shown-at 22.A f f The form of construction shown in Fignre 3 is generally similar to that shown in Figure-1 and comprises a cylindrical hearth portion( 23, Haring bosh portion 24, inwardly inclined shaft portion 25 formedas the frustrum of 'a cone, and a topmost portion 26 11,5

1 formed as an inverted frustrum of 'a cone and meeting the portion 25 on .'l-ine 27. The charging bell is shown at28.

In Figure 4 we have shown more in detail aform ofconstruction similar to that shown 12 in Figure 1. Here the metal kfurnace shell 29 is provided with a brick lining 30 and 'with the stock linevpro'tecting` plates 31.' These plates 31 are located at the line of junction between the shaft portion of th'e furnace and the outwardly Haring portion 32, andare tied into the shell 29 by connecting plates The olftake passages 34 serve to carry the products of combustion and blast gases vto the downcomers. The lower charging bell 35 o 'may be operated .by any usual bell operating mechanism and is 'shown as engaging the lower hopper section 36.

The details of construction of the bricky work and stock line protection plates are4 shown in Figures 5 and 6. The brick lining 130 is shown as-provided with a series of plates .extending portions40 bonding them to the brick work and having the T-shaped heads 41 which protect the faces of the brick work Aimmediately below the stock line. protection plates 31.. These plates 31 have extensions 42 which are located behind the T-heads 41 of g the pilates 39 and serve to hold thelower edges of the plates 31 in place.

The upper edges of the plates 31 have inwardly extending portions 43 and vertically extending portions 44, these latter engaging back of the vertically extending po tions 45 of the connecting plates 33. As bfst shown in the horizontal section of Figure ,the connecting plates 33 are provided wit the extensions 46 which-engage behind the T-heads 47 of the rails or tracks 48. These rails or tracks 48 are secured tothe inner surface of the metal shell 29.

It will be noted that the upper portion 49 of the metallic shell 29 extends upwardly inside the furnace, the upper portion of which is enclosed by the upwardly flaring shell section 50. The topmost portion; 51 of the main brick work in the furnace is located inside of the shell extension` 49.l The brick work 32 in the uppermost portion of the furnace is thus supported by the plates 49 and 50 independently of the main body of the brick work in the furnace. Therefore any vertical eX-' pansion or contraction of the main brick work will not affect the uppermost brick work 32. It will valso be apparent that due to the sliding connection between the plates 33 and the T-sliaped rails48 substantially no stresses are set up in the shell and there is no ruptur? ing of the brick work when the brick work moves under expansion and contraction.

There are no holes or openings in the brick work necessary, as is the case where usual v types -of tie rods or bars are used to hold the.

brick lining back against theI metal shell. The stock line protection plates are effectively tied into the brick work and will not become loosened and fall out upon the impact of the incoming material. It will beap- 'parent from a consideration of Figure 4 that the incoming material will strike the inwardly sloping surfaces of the upperportion of the furnace and will be directed inwardly toward the center of the furnace. This will serve to reduce the usual depression below thebell and will more uniformly mix the various sizes of material throughout the cross sectional'area of the furnace.

While we .have shown certain preferred embodiments vof our inventionjby way of example, it is capable of change and modification to meet varying conditions'and requirements,'land'wev contemplate buch Variations and changes as come within the spirit and scope of-the appended claims.

' We claim:

1. In a vertical shaft furnace, an intermediate portion and an upper portion, brick work lining the intermediate sect-ion and brick Work lining the upper portion, the brick work of the upper portion being supported independently of the brick work in the intermediate portion. A

necting the shell and lining, said means hav-'1 ing a sliding connection with the shell.

4. In a vertical shaft furnace, a metal shell, a brick lining for the shell, and means connecting the shell and lining,-said means comprising vertically extending T-shaped members secured to Athe Shell and members car- 'ried by the brick work and slidably engaging the T-sha ed members.

5. In a last furnace, a metal shell, a brick lining, an upper outwardly flared portion ofthe brick lining located at the stock line,

- 2. In a vertical shaft furnace, a metallic shell, an intermediate portion and an upper and means slidably connecting the brick work to the shell at the stock line.

6. In a blast furnace, a metal shell, a brick lining, an upper outwardly flared portion of the brick lining located] at the stock line, and means slidably connecting the brick work to the shell at the stock line, said means including stock line protection plates on the inner surface of the brick and means slidably connecting @aid plate to the shell.`

7. In a blast furnace, a metal shell, a brick lining, metal stock line plates fitted upon said brick lining, and means slidably connecting said plates to the shell. V

8. In a blast furnace, a metal shell, a brick lining, metal stock line plates fitted upon said brick lining, and means slidably ponnecting the plates to the shell, said means including vertically extending traclg members and members extending through the lining conv nect'ed to the plates and slidably engaging the tracks. f

9. In a blast furnace, a metal shell, a bric means slidably connecting the connecting plates to the shell. f Y Y 10. jIn a blast furnace, a metal shell, a brick li/ning, stock line plates fitted in the i brick lininVr at the stock line, said plates hav- 'ng inwardly and vertically extending portions, connecting plates having verticallyA extending portionsengaging'the vertically extending portions of the stock line plates, `verlo tically extending T-shaped tracks secured to the inner surface of the shell, and portions formed on the connecting plates extending behind the heads of the T-shaped tracks to slidably connect the connecting plates and 15 stock line plates to the shell. i

11.4 In a blast furnace, a furnace shaft havan upper portion extending below and above the stock line and flaring outwardly Y whereby the upper portionof the stock has a greater gas releasing area than a lower portion ofthe stock whereby .gas velocity is reducedat the upper stock surface and gas olftakes in communication with the entire upper surface of the stock. 12. In a blast furnace, a furnace shafthaving walls sloping upwardly and inwardly and an upper'wall portion Haring upwardly and outwardly, 'the junction of the two portions being located below the stock line, a curved portion at the junction whereby the interior of the upper portion of the furnace is of generally Venturi section and gas oftakes in communication with the entire upper surface of the stock.

13. In a blast furnace, a shaft having walls sloping inwardly and upwardly and an upper section sloping outwardlyand upwardly, the plane of junction 'of the oppositely sloping walls containing a lesser furnace interior cross section than lplanes thereabove, said plane of junction being located below the stock line, and a. bell rcarried by the furnace top at a point materially above the plane of minimum charge material directly against the upper outwardly flaring walls whereby thematerial is directed by said walls inwardly and f downwardly lto reduce the stock depression `below the bell.

1f In a blast furnace, a shaft having walls sloping inwardly and upwardly and an up-v per section sloping outwardly and upwardly,

the plane of junction of the oppositely sloping walls containing a lesser furnace interior cross section than planes thereabove, said plane o'f junction being located below the stock line, a bell carried by the furnace top at a point materially above the plane of minimum furnace area and sloped to discharge materialY directly against the upper outwardly. flaring walls whereby the material is directed by said walls inwardly and down- Y wardly to reduce the stock depression below the bell and gas oftakes connected to the upper' portion of the furnace and communifurnace area and sloped to 'dis-v eating with the space above the entire upper stock surface. Y

15. In a blast furnace, a shaft having walls sloping inwardly and `upwardlyand an upper section sloping outwardly and upwardly, the plane of junction of the oppositely sloping walls containing a lesser furnace interior cross section than planes thereabove, said l.

plane vofjunction being located below the stock line, and a bell carried by the furnace topat such a height above the stock line4 and so sloped as to discharge material directly against the upper outwardly Haring walls which causes the materials to lie closely'

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