US1970221A - Air supply means and method for cupolas - Google Patents

Description

R. 8. BROWN AIR SUPPLY MEANS AND METHOD FOR CUPOLAS Aug. 14, 1934.

Filed Nov. 9. 1931 5 Sheets-Sheet 1 [72 U678 2, 07" jigerfihccrf fimzwz/ 1 Aug. 14, 1934. R. s. BROWN AIR SUPPLY MEANS AND METHOD FOR CUPOLAS Filed Nov. 9, 1931 3 Sheets-Sheet 2 Invemzfor fi oyerfizfmrf .Bmzwz Aug. 14, 1934. R. 5. BROWN 1,970,221

AIR SUPPLY MEANS AND METHOD FOR CUPOLAS Filed Nov. 9. 1931 5 Sheets-Sheet 5' 1720672250? Zggerfiaaamfrawr'a Patented Aug. 14, 1934 r v i UNITED PATENT V '1,9'70,2 2'1".; I V AIR se ia MEANS Ass stant FoR oUroLAs r Roger Stuart Brown,"Ch ioago,' Ill. Application November 9, 1931, scram. 574,176

9 cla ms; (o1."2c 14) This invention relates to improvements in blast able inlet pipes Bwhich Communicate with the furnaces, and more particularly tocupolas. One bustle pipe B Assuming the connection with object is to provide a durable, low cost, hot'bl'ast the usual blower, when the cupola is in operation cupola which will melt or smelt withagreat econ and the blower starts to Ope it forces omy of fuel, or at a highertemperature, or with through the pipe B and the bustle pipe B for both results. For certainoompositions, melting distribution for example through the nipples B at a higher temperature produces a better grade 130' th h at p p Order to p e of cast iron, probably due to thecomplete solustrain on the parts due to variations in ten1peration of the carbon at: the higher temperature. ture I may provide any suitable flexible connect- I 10" Another advantage is the possibility of melting ing m ans, f r xampl the flexibl xp n a'gre'ater proportion oran entirety of steel scrap, joint c p ings B between the nippl B and B. without a prohibitive fuel ratio or liability of It will be seen from reference to Figures 1, 2 and freezing or bridging. Another'adva-ntage is S'that the pipesl; are cl sely dj nt he inner that the much smaller quantity of fuel required. Wallof the refractory liningA said refractory V 15 results in less sulphur absorption, of paramount ing being e sod a at A t give om for importance in melting iron suitable for malleabil them. Notwithstanding the close spacings of izing. The higher temperature, less, sulphur abhe 911F 53? h re i i he forms Shown in F sorption, and high percentage of steel scrappos ures1 l t sufficientspacing between adjacent sible, enables the making of pearlitic high p pes a d b tw n p p and the refractory v 2o '1 strength iron, which could heretofore bemade lining to permit the heated gases of combustion only in an electric or air furnace with greatly in to contact allfsides of each pipe. At least a small creased fuel and investment costs. Otheradvarrquantity'of the-productsof combustion rises be tages will appear from time to 'time'in the spectween and behind the pipes B so that they are ification and claims. 7 heated to some extent on the sides and back as p 25 The present applicationis a continuation in well as on theinner face which is in contact with part of my application, Ser. No. 371,156, filed on the descending charge and the burned gases pass- June 15, 1929. ing up'through it. The res'ult is a heating eiiect -I illustrate my invention more or less diagreater than if the pipes were abutting or heated grammatically in the accompanying drawings," on only the inside face. Furthermore, heating 30 *wherein 1 ,7 v the pipes on all sides reducesthe tendency to Figure 1 is a vertical section through a cupola Warpingand growth' on the front or inside face of my invention, one half beingan outside eleva otthe pipes r H tion'; i The heated air passes through the pipes B Figure 2 is ahorizontalsectionon-the1ine2 2" through nipples B7 and 3 connected by the H 35"of Figure 1; flexible connection BL'into the .hot air bustle Figure 3 is an enlarged horizontal section er pipe B f a a'part of-Figure 2; A J Communicating with :the hot air bustle pipe Figure 4 is a section similar to Figure '3 through B?" are the hot air down-comer pipes .C. In avariant form; 1 I orderto provide for expansion and contraction 4 Figure 5is a detail of one of the tubes of Fig these pipes ma have inte posdr t r any lire iand suitable flexible or" expansion connection .0

Fi ur s 6 and are pa tial h rizont l's t The ends c ofthe'pip'es'Ccornmunicate with the each through a n t m I wind-boxer tuyere'bustle pipe C which may 7 Llke are q by k? S m connectdirectly, or through bootlet boxes C s 45 throughout the specification and drawings; I with r s of tuyre's C5 C6 the'drawings A indicates "theshell R i i to One or more connecting pipes D may-extend of the cupola WhlCh may be supported onany f th h d b t h suitable frame'or supportingstructure A withrpm 2 9 1 eirwor us is 0 t e itsbottomplate 2- pp-b ti g'1 g' 3.I-, hy': bustle (F whereby a contlolled fraction of the 50 suitable closure means'may be providedffo'r the W t m be bymassed, permlttmg hole in the bottom plate A the detailsthereof: wlthmllmltse ee e t i blast t aforming no part per se oifithepresentinvention'; i ture entering theituyeres. In order to control h ig shown at' A6 in 'F1gur "1 A passage of air through the passages D, I may indicates'arefractory liningfortheshellA: provide'any 'suitable'valve mechanism D Each '55- In ordftovpre'heatthanI employ hnysuit" 1 Such y e controlled manually but. I il- 11b lustrate diagrammatically any suitable thermostatic control member D Referring to Figures 4 and 5, I may employ instead of the pipes 18 the pipes E of circular 5 cross-section. Each such pipe, as shown in Figure 5 has an upper integral nipple E and a lower nipple E which may extend to any suitable fiexible or expansion couplings E G indicates the sand bottom for the coke bed. G indicates the melting zone and G: the charging door.

Figure 6 illustrates a variant form in which the air passages H, corresponding to B of Figure 2, are bounded on two faces by. the arcs H H which may be concentric with the axis or center of the cupola. The passages are separated from each other by the arcuately walled spaces H Figure 7 illustrates another variant form, which the air passages or ducts J are bounded by the generally plane surfaces walls J being separated by the plane walled passages J Preferably, as in the form of Figures 2, 6 and 7, the

air passages B H or J, as the case may be, are

' separated from each other by passages of generally uniform width and are separated from the refractory lining A by spaces of generally uniform width.

It will be realized that whereas I have deso; scribed and shown a practical and operative device, nevertheless many changes might be made in the size, shape, number and disposition of parts without departing from the spirit of my invention. I therefore wish my description and drawings to be taken as in a broad sense illustrative and diagrammatic rather than as limiting me to my specific showing. In particular I wish to be understood that I do not limit myself to any particular size, shape or combination of parts except so far as I specifically limit myself thereto in any individual claim.

' The use and operation of my invention are as follows:

' In employing my invention I pass the air blast of ablast furnace .or cupola through an air 'jacket or series of pipes set around the shaft intermediate the level of the melting zone and the charging door. The length and the location of these pipes may vary with the choice of mam terial and its possible heat resistance. Preferably they do not extend lower than two feet above the upper limit of the melting zone as de fined as the point of greatest cutting' away of the refractory lining. This might be five or six 5 ,-feet above the upper level of the tuyeres. 'If they are brought down lower it is at the expense of employing very highly heat resisting material for the pipes, with the consequent increase in the initial investment and probably in the 6o; .maintenance cost. To raise their lower ends much above four feet above the melting zone results in a decrease of efficiency.

An important feature of my invention is that by limiting the total cross-sectional area of the ca -air passages shown at 13 I increase greatly'the amount of heating effect obtainable from the maximum amount of surface it is possible to place within the cupola. At the same time the heating area of the pipes or pipe walls is infik creased by the employment of a plurality of in dividual pipes and passages and by admission heater will run so, much hotter than with the the excess of carbon monoxide (CO) gas. Therethe. adequate exposed or heating wall area is to great pressure loss, and hence with a saving in power in running the blower.

Taking the structure as shown for example in Figure 2, I illustrate the passages 13 the preferred radial width of which is about 1/28 of the inside diameter of the general cupola passage defined by the inner walls or faces of the members B In practice I find that a reasonable range of variation in this ratio is from 1/14 to 1/56 of the diameter of the cupola. As small a width as 1/56 is about as small as can be used without getting an -excessive power consumption of the blower, and although the heating effect and fuel economy is better, it may usually be preferable 'to use a greater width of passage. On the other I find that a width of passage greater than 1/14 of the inside diameter of the cupola, while resulting in a minimumof power consumption, reduces the pro-heat and fuel economy. Further, the metal of the presmaller ratios, that the maintenance cost is high.

In operation the cupola may be=made up with a sand bottom coke bed and charges in the usual manner. When the blower starts its operation it forces air through the inlet pipe B. The cold air so supplied fills the bustle passage 13 and thence passes through the heat passages B Note that the direction of travel of the air in the passages B is indicated as parallel with and in the same direction of travel as the by-products of combustion. This arrangement is preferred but I do not wish tobe specifically limited thereto except so far as I limit myself in my claims. By passing the air along a path or paths parallel with the ascending gases from the combustion, but passing the air in an opposite direction to the direction of movement of such gases, a somewhat increased pre-heating efficiency is obtained, but

at the expense of a greater deterioration of the materials and a resultant necessity of greater investment in heater pipe material of greater heat resistance. .As the air enters the relatively restrictedpassages B its velocity increases due to the small cross-sectional area of the vertical sections of the heater pipes. Heated by its quick passage through the pipes B around which the burned or burning gases are flowing, it issues through the nipples B B to the hot air bustle pipe C. It thence passes to the wind box C and thence to the tuyeres C or C Inasmuch as it may be advantageous to control to some extent the temperature of the air I provide means, in?- cluding the passages D and the valve D for -by-.. passing a certain proportion of the cold air from the bustle B to the wind box C .I find it advantageous to place the air heater sections or passages below the charging door.

'They are in a position where they are exposed to a practically nonoxidizing atmosphere, due to fore they are relatively free from the scaling ofmaterial of low heat resistance which takes place in constructions where the air heater sections are placed elsewhere. It is important to properly relate the length of the passages B to their cross-r sectional area in order thatthe rapidly moving air will pass through a passage of sufficient lengthand with asufiicient exposed wall area to get the desired heating effect. One method of obtaining heat all sides of the passages, as shown in the accompanying drawings; 1

One advantage, ofmy construction involving only one straight passa e of the air through heator elements parallel with the movement of the furnace gases, is that it is possible to make the air heating elements without any joints exposed to the high temperature.

I claim:

1. In a hot blast cupola, a cupola member, an air blast inlet passage, a plurality of air preheating passages in communication therewith, positioned within said cupola, a charging door for said cupola, said air preheating passages being located substantially below said charging door and means for delivering the air to be pre-heated from said air blast simultaneously to the same end of each of said pre-heating passages, a plurality of tuyres, and means for delivering heated air from the opposite ends of each of said preheating passages to said tuyres, the radial width of the passage being in the range of from 1/56 to 1/14 of the interior diameter of the cupola.

2. In a. hot blast cupola, a cupola member, an air blast inlet passage, a plurality of tuyeres and means for pre-heating air for delivery to said tuyeres, including a plurality of generally straight pre-heating passage members positioned within said cupola and in general parallelism with each other, and means for maintaining a flow of air therethrough, in parallel, with a like direction of flow in all passages, the radial width of the passages being in the range of from 1/56 to l/14 of the interior diameter of the cupola.

3. The structure of claim 2 characterized in that the pre-heating passage members are spaced from the inner wall of the cupola, the space between the cupola and the passages being open for the passage of the hot gases through the cupola.

4. The structure of claim 2 characterized in that -the individual pre-heating passages are spaced from each other and from the inner wall of the cupola, the spaces between the individual passages, and between the passages and the cupola being open for the passage of heated gases through the cupola.

5. In a hot blast cupola, a cupola member, an air blast inlet passage, an air pre-heating passage in communication therewith, spaced within said cupola and a charging door for said cupola, said air preheating passage being located substantially below the level of said charging door and being spaced radially inwardly from the opposite inner face of the cupola, said passage having a radial width generally equivalent to 1/28 of theinte rior diameter of the cupola, means for delivering the air to be pre-heated from the air blast to one end of the pre-heating passage, and means for delivering heated air from the opposite end of the passage to theinterior of the cupola.

6. In a hot blast cupola member, a charging door for said cupola, pro-heating air passage elements, which include a portion positioned within the cupola and centrally spaced inwardly from the opposite inner face of the lining and being located substantially below the level of the charging door, and integral angularly extending end portions at the ends thereof extending outwardly through the cupola wall and removable flexible connection means associated with said ends, positioned substantially without the wall of the cupola.

7. In a hot blast cupola, a cupola member, a charging door therefor, a refractory lining therefor, pre-heating air passage members positioned within said cupola and being located substantially below the charging door level and spaced inwardly from the opposite inner face of said lining sufficient to define a gas passage of small but uniform width between the inner face of the refractory lining and the opposed faces of the passages, the passage faces remote from the refractory lining being adapted to contact the charge of the cupola, said passages being generally rectilinear in axial extension, and parallel with the axis of the cupola, the radial width of the passages being in the range of from 1/56 to 1/14 of the interior diameter of the cupola.

8. In a hot blast cupola, a cupola member having a charging door, an air blast inlet passage, a plurality of air heating passages in communication therewith, positioned within said cupola member and located substantially below the charging door and spaced centrally inwardly from the inner face of the cupola at that level, said passages having a radial width generally equivalent to 1/28 of the interior diameter of the cupola, means for delivering the air to be pre-heated from the air blast inlet passage to one end of the preheating passages, and means for delivering heated air from the opposite end of the passages to the interior of the cupola.

9. In a hot blast cupola, a cupola member having a charging door, an air blast inlet passage,

a plurality of air preheating passages in communication therewith, and located substantially below the charging door, and spaced centrally inwardly from the inner face of the cupola at that level, said passages having a radial width in the range of from 1/56 to 1/14 of the interior diameter of the cupola, means for delivering air to be pre-heated from the air blast inlet to one end of the preheating passages, and means for delivering preheated air from the opposite end of the passages to the interior of the cupola, said air delivery means being adapted to maintain a flow of air through said passage in parallelism with the path of movement of the heated gases upwardly through the cupola, and in the same direction.

ROGER, STUART BROWN.

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