US2471776A - Air supply apparatus for cupola furnaces - Google Patents

Description

ZvSheets-Sheet l H. A. REECE AIR SUPPLY APPARATUS FOR CUPOLA FURNACES May 31, 1949.

Filed March 24, 1947 r 1 f/ ILM 4 45 INVEN 0R.

H. A. REECE AIR SUPPLY APPARATUS FOR CUPOLA FURNACES May 31, 1949.

2 shets-sheet 2 r Filed March 24, 1947 Patented May 3 1., 1949 oEErcE AIR SUPPLY APPARATUS FOR CUPOLA FURACES Herbert A. Reece, Cleveland Heights, Ohio Application Marclf24, 1947, Serial No, 736,781

1` This inventionhas to do with the supplying ot air to metallurgical furnaces and relatesmore particularly to furnaces of the cupola type having a group or series of spaced tuyres and windbox means for supplying air to the tuyres.`

`In the operation of furnaces of thiskind the quality of the melt andv the characteristics of the castings obtained.therefrom` `are dependentv upon the attainment of a uniform condition in the combustion zone and this, in turn, isV dependent uponvthe attainment of afsubstantially equal dis-n tribution of the air supply to the individual `tuyres of the tuyre group or groups. Heretofore'various meansand methodshavebeen em ployed in endeavoring to achieve such an equal distribution of air and, so far as I am aware; all such attempts; have soughtto eliminate disturbance in the air stream and to obtain af now WhichV is relatively smootlfand' substantially de-v void of abrupt directional changes.`

The present invention represents a radical departure from suchiprior practice andobtains" the desired substantiallyrieq'ual distribution of air' vtothe tuyres bydeliberately producing additional disturbance in the air stream bymakinglabrupt" directional changes in advance of its deliveryt'd' the tuyres. As further' explained hereinafter; the disturbance is createdin the airfstream while it is passing through the-windbox and is produced` by using; in a novelmanner, a velocity discharge" of the air` supply into the f1 windbox. By i creating"I suchA a disturbance in theair-"stream as it enters' the1windbox the air being supplied distributes itself therein sothat substantially thesame?pres@u sure and velocity'factorswill exist in? the windbox for all points `of a given cross sectionand this will substantially eliminate -high and-low pressure areas, dead spots, andthe like, and will-result in` a: substantially equalow rof air to all of theT4 tuyres` being supplied'f `by that! particular vv-indl* box.

It is. therefore an1 object o'f this* invention to provide: a novel air supply means fora furnace of-` :this character inlwhich a substantially equal distributionV ot air to- .the individuall tuyres `of axgroup is obtained by creatinga disturbance the'stre'am of` air being supplied to such group.L

A'ffurther object is" to `provide an air supply for a.: group i of furnace tuylres-` in which" a: windbox` serving1 suchgroup embodies novel means for usingfthe'fvelo'city, ora` portion ofthe v'elo'cityj` of the` air" supply forobtainingf substantially equal distribution of the air tovallportions `of the wind! boxzxand the delivery of substantially equalwvolurnes ltothe individual` tuyres of thelgr'oup.A

` 2 claims.` (ci. 2st- 30) Still another object is to provide air supply* means of this character in which the air isf delivered to the tuyres of the group 'from theF lower end of the windbox and additional dis-- i turbance is created in the air stream by directing of the Vwindlzvox and against which theincoming:

air stream impinges.

Yet another object is to provide the windbox with an elongated air inlet opening which has a length approximately equalto the width of the windbox.

As another ofitsY objects this invention provides a cupola of the rectangular type having rows of tuyres in opposed wa'llsserved by' separate wind# boxes'.

Other objects and advantages of the invention will -be apparent from the following description' andv the'` accompanying sheets `of drawings in which Fig. l` is a side elevation of a furnace of the' cupola type showing the same equipped `with th'e equalizing air supply means of the present invente' tion andV with portions of one ofthe windboxes broken away; l

Fig?. 2v isA atransvferse sectional View of the1 cupola taken substantially at the plane of the air" inletopenings as indicated by line 2 2 of Fig'.` 3;

Fig. 3-isap1artia`1 vertical sectional View taken' substantially on line`34`3 of Fig; 2;

Fig. 4 is a partial side elevationsimilar' to Fi'g. 1r` but showing-a modiedcons'truction;

Fig.. 5 is' anotherl suchpartial side elevationA showing another modifying construction;

Fig; isfa partialverticalsectional view taker online 6-'6` of' Fig. 5; and

Fig; '7* is a`v sectional detail View showing" the' clamp adjustment provideill on the distributing vanes off the air supply nozzles.

Proceeding now with`- a` more' detailed descrip" tion ofthe invention, Figs'. 1; 2'v and 3 show' a furnace IB of the cupola type havingJ anJ upright hollow cupola body Ilcontaining a furnace shaft |25` The-cupolabdyll has opposedsubstantially flat side walls? l3` and i4 and@Olglpo'sed` end` walls l5 andi I6 Tliesid and endwalls are formed` by an*outermetalshll Il and a refractorylining |82* The'cupolabody |l`l is rectangular in cross" sectional lshapfand is provided withy groups or rows o'fftuy'resA 1919 and 1 2ll-located` in the opposed` i, y .A slag hole 21' can ,be provided infoneof the* eiidfvva11s,v iii this instance the end wall I5, and a tap hole 22 can be provided in the opposite end wall. The slag and tap holes are provided with appropriate spouts 23 and 24 as shown in Fig. 3.

As -indicated above in a general way, it is important in the operation of Ia lfurnace of this 'type that air be supplied simultaneously for the two opposed groups of tuyres I9 and 20 and be supplied in streams having substantially equal volumes and velocities. It is also important that the individual tuyres of the two EIOU-ps be Supplied with air of substantially equal volumes and velocities. rI'his is accomplished by the novel air supply means and method which will now be described.

Windboxes 26 and 21 which, las here shown, may be substantially ilat structures mounted on the outside of the substantially flat side walls I3 and I4. These windboxes have upright substantially flat front or -outer `walls 26a and 21a and u their upright rear or inner walls 2Gb and 21o may be formed-by portions of the shell I1 of the cupola body. The windbox 26 has opposed upright side walls 26c and 26d, and lthe windbox 21 likewise has opposed yupright side walls 21e and 21d. The walls of the airbox 26 dene an upright air ohamber 28 which is of sufficient width to serve all of the tuyres |9 constituting one of the tuyre groups and may have a width approximately equal to the width of the side `wall |3. The walls of the windbox 21 likewise define an upright eair chamber 29 of a width approximately equal to the length of the side wall I4 and capable .of serving all of the tuyres 26 of the other group. The inclined plates 42 and 43 form the tops of windboxes 26 and 21 respectively.

' The air supply means also includes a main duct 30 extending from a blower or other suitable source of air under pressure and a pair of branch ducts 3| and 32 which extend respectively to the windboxes 216 and 21. The branch ducts 3| and 32 Iare connected with the main duct 30 by means of a Y-fitting 33 which is preferably provided with a division plate 34 for insuring a substantially equal division of .the air supply between the two branch ducts.

The branch yducts 3| and 32 are connected with these inlet openings 36 land 31 by means of laterally elongated divergently tapered or ilared nozzles 38 and 39. These nozzles are provided with distributing vanes 38aand 39a extending in diverging or radiating relation and which serve to distribute the flow of air over the entire width of the inlet openings.

In connection with the nozzles 38 and 39 it should be noted that these nozzles are disposed so that they extend in a direction substantially normal to the front walls 26aand 21a or the windbox 26 and 21. This position for the nozzles causes the velocity discharge of air into the windboxes to take place in a direction crosswise thereoi, that is to say, in a direction substantially at right angles to the Idownward direction of flow which the air must subsequently followin passing to the tfuyres.

f By reason of the divergent shape of the nozzles 38 and 39 and the use of the distributing vanes therein, the streams of air constituting the velocity discharges into the windboxes 216 and 21 will be laterally :elongated substantially flat streams corresponding'with the laterally elongated shape of the inlet openings 36 and 31. When these flat streams of air are directed into the .'windboxes lina direction orosswise thereof as just mentioned above, they `will impinge 4 against the inner or rear walls 26h and 2112 of the windboxes, or against the delector plates 40 and 4| as the case may be, and this will cause great disturbance in the air streams because they will be subjected to an abrupt ldirectional change.

In the embodiment of the invention here illustrated the drawings show the tops of the wind- !boXes 26 4and '21 as being `formed by the laterally elongated deflector plates 40 and 4| which are located opposite the laterally elongated inlet openings 36 and 31. When the air streams are directed into the windboxes by the nozzles 38 and 39 they impinge against these deflectors in a direction normal to fthe surface of the deflector. The deilectors 40 and 4| can be omitted, in which case the air streams impinge directly against the rear side walls 2Gb and 21h as mentioned above. When the upper ends of the windboxes embody the deilectors 40 and 4|, inclined plates 42 and 43 may be located over the upper ends of the windboxes to serve as sheds for water, dust and the like so as to prevent an accumulation of such materials in the pockets existing behind the deilectors.

The tuyres I9 and 26 are connected with the lower ends of the Windboxes 26 and 21 by prioviding tuyre boxes of ith-e so-Galled drop type or by any other suitable tuyre construction which will provide the necessary air passages from the lower ends of the Windboxes to the tuyre openings |9a and 20a. In Figs. l-S, inclusive, individual tuyre boxes 4i and 45 are shown which are separated by upright partitions 44a. and 45a and which are connected with the windboxes through air delivery openings 4'6 and Because of the novel way in which the air stream is supplied to each windbox, the straight line ow is disturbed and broken up so that pockets of unequal pressure are avoided and the pressure over the ent-ire cross sectional area of the windbox is substantially the same. When the downwardly moving air stream strikes the bottom of athe windbox some of the remaining velocity of the stream Will be 4converted into pressure but the pressurefactor will have substantially the same value .for all points in a given transverse plane or cross-section of the windbox. The `air then ows `from the Windbox through the delivery openings to the tuyre group I9 and 20 and, since the air stream has equalized pressure values as just explained, the air passed through each individual tuyre of a group Will be substantially the same in volume and velocity.

Reverting to the distributing vanes 38a and 39a of the air supply nozzles 38 and 39 it should be explained that these vanes can be in fixed relation in the nozzles or, if desired, can be laterally adjustable so as to permit them to be located in the proper position to obtain the equalized distribution Iof the air being delivered to the air inlet openings 36 and 31 of the windboxes. For the purpose of this adjustment some or all of the vanes have a pivot 48 -W-hich permits lateral swinging. The adjustable van-es are adapted to be clamped in the selected position by va clamping means such as that shown in Fig. 7 and which comprises a screw or stud 48a projecting through a slot 48h in the wall of the nozzle and having a nut 48c lther-ecn bearing against a washer 48d which spans the slot. Members 38h connected to the vane fform a cover for the slot and prevent the -loss of air therethrough.

. Fig. Lishovvsa furnace t9 of the cupola type similar-to the-furnace. I0 above described but in4 which a modied construction is employed for connecting the lower ends of the windboxes 50 with the passages Sla of the tuyres 5I. In this modified construction the upright partitions 14a and 45a have been omitted and laterally continuous tuyre boxes 52 are provided for the groups of tuyres.

Figs. 5 and 6 show another furnace 53 of the cupola type which is similar to the furnace I0 above described but in which the windboxes 54 are extended downwardly to a point below the tuyres 55 and the air inlet openings 55a of the tuyres extend through the shell 56 forming the rear wall of the windbox.

From the foregoing description and the accompanying drawings it will now be readily understood that this invention provides a novel construction for supplying air to a furnace of the cupola type and particularly for a cupola of quadrangular cross-section having groups of tuyres in opposed walls. It will now also be understood that the division plate 34 in the Y fitting 33 can be set so that equal Volumes of air will be supplied to the separate windboxes through their respective nozzles with the result that all the tuyres leading into the furnace shaft will supply substantially equal volumes of air at substantially the same velocity` Also, if it is desired the division plate can be set so that the tuyres of one windbox will supply more air to the shaft than those of the other windbox, and any desired ratio of quantities of air can be obtained.

Although the improved air supply means of my invention have been illustrated and described herein to a detailed extent; it will be understood of course that the invention is not to be regarded as being limited correspondingly but includes all changes and modications coming within the scope of the appended claims.

Having thus described my invention, I claim:

1. A cupola having a rectangular shaped shaft having a separate windbox on each of two opposite sides, each windbox having a set of tuyres, a common main blast line for supplying air to said windboxes, a proportioning valve in the main blast line to permit selective proportioning of air to each of the windbox inlets so that the tuyres of one windbox may supply an equal, greater or less volume of air to the cupola shaft than the tuyres of the diametrically opposite windbox, the portion of each windbox opposite the inlet being provided with a curved delector plate facing the inlet deflecting the air toward the tuyres to obtain substantially equal air velocities in the tuyres of either tuyre set.

2. The furnace as described in claim 1 wherein the deector plate is of parabolic shape.

HERBERT A. REECE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,546,521 'Vanderstein July 21, 1925 1,788,888 Reid Jan. 13, 1931 2,188,920 Reece Feb. 6, 1940 2,273,902 Smalley Feb. 24, 1942

Images