US2687294A - Pressurized cupolas - Google Patents

Description

Allg- 24, 1954 H. A. REI-:CE

PREssURIzED CuPoLAs s sheets-sheet 1' iled April 21 1951 ATTORNEYS Aug. 24, 1954 H. A. REECE PRESSURIZED CUPOLAS 3 Sheets-Sheet 2 Filed April 21 1951 \QLV a@ L X IN VEN TOR. Easem- AKeece BY 3 Sheets-Sheet 3 H. A. REECE PRESSURIZED CUPOLAS Aug. 24, 1954 Filed A prl 21 1951 INVENTOR.

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Patented Aug. 24, 1954 UNITED STATES PATENT GFFICE PRESSURIZED CUPOLAS Herbert A. Reece, Cleveland Heights, Ohio Application April 21, 1951, Serial No. 222,190

(Cl. 26S-25) 11 claims. 1

This invention relates, as indicated, to pressurized cupolas.

- It has heretofore been proposed to solve the problem of uniform distribution of air through a cupola charge, as by the use of a removable orice ring, which creates the desired static pressure in the stack, the velocity of air through the charge remaining constant since it is governed by the orifice ring and the volume of air it handles. Such a vpressurized -cupola is described on page 127 of the September 1950 issue of The Foundry. The pressurizing of cupolas in this manner has been lextremely difficult of attainment, due to the fact that the circular shape or design of the conventional type of cupola has necessitated, for this purpose, either the use of complicated and expensive equipment of the iris diaphragm type, or the use of cup and cone or bell and hopper equipment, borrowed largely from blast furnace design or practice.

I have found that the problem of pressurizing a cupola can be solved in a relatively simple and inexpensive manner by utilizing a cupola of rectangular cross-section, as disclosed, for eX? ample, in my Patent No. 2,471,776.

A cupola of this rectangular shape lends itself readily to the incorporation therein of pressurizing means or devices, which are of extremely simple construction and which can be installed at a fraction of the cost of installing pressurizing equipment in cupolas of circular or conventional design.

'By utilization of pressuring means or devices in accordance with my invention, I am able to use relatively high air pressures in the combustion zone of the cupola, thereby providing improved eombustion, hotter iron, increased melt per square inch of cupola cross-sectional area, greater fuel economy and more uniform operation of the cupola, and to avoid or minimize bridging of the cupola by slag.

YOther objects and advantages of the invention will become apparent during the course of the following description, when read in conjunction with the drawings forming a part of this specification, and in which like numerals are employed throughout tc designate like or corresponding parts.

In said annexed drawings,

Fig. lis a fragmentary vertical"cross-sectional View through a cupola similar to that shown in my aforesaid Patent No. 2,471,776, and having incorporated therein one form of pressurizing means embodying novel features of the invention;

Fig. 2 is a fragmentary vertical cross-sectional view, taken on the line 2-2 of Fig. 1;

Fig. 3 is a fragmentary transverse or horizontal cross-sectional view, taken on line 3-3 of Fig. 1, with two of the three plates inlowered position;

Fig. 4 is a view similar to Fig. 3, but showing a modified form of pressurizing means or device;

Fig. 5 is a fragmentary vertical cross-sectional View taken on the line 5-5 of Fig. 4;

Fig. 6 is a fragmentary view, showing in greater detail the plate lock mechanism of Fig. 4, and

Fig. 7 is a fragmentary cross-sectional view, taken on the line 'I-'I of Fig. 6.

Referring more particularly to Figs. 1, 2 and 3 of the drawings, the cupola will be seen to comprise an upright hollow` cupola body having opposed substantially flat side Walls I and 2` and opposed substantially fiatend walls 3 and 4. The side and end walls are formed of an outer metallic shell 5 and a refractory lining 6.

The wall 2 has a charging opening therein, defined by upper and lower edges I and 8 respectively, and side edges 9 and II).

Directly opposite the aforesaid charging opening, the back wall I of the cupola is constructed to provide a recess I I, which is dened byA a vhorizontal rearwardly extending ledge I 2, sides I3 and I 4 which are rearward extensions of the end walls 3 and fi respectively, a rearwardly and downwardly inclined top wall I5 and a rearwall or back I6, which inclines rearwardly from the rear edge of the ledge I2 to the rear edge of the top wall I5. Y

Disposed within the recess of area thus described is a series of plates Il, I8 and I9, which are pivotally secured at their lower edges to a pivot pin or shaft 26, the ends of which are secured in the walls I 3 and I4.

The plates I7, I8 and I8 are of substantially rectangular form and are preferably made of stainless steel or other metal resistant to corrosion and heat. The plate I1 has a rectangular opening I'Ia therein of fairly'large `-area; The plate I 8 has a rectangular opening ISa therein of somewhat less area than the area Ila, Yand the plate I 9 has a rectangular opening I9a therein, of somewhat less area than the area IM. The openings I'Ia, I 6a and I9a are aligned axially with each other and with the axis or center of the shaft, when in operative position.

The openings in the plates may beA of various areas or sizes, and the areas can be predetermined in accordance with actual operation conditions of the cupola. In a cupola, for example, having a stack or shaft whosecross-section is 36" x 48", or

a cross-sectional area of 1728 square inches, a plate or leaf having a rectangular cut out or opening 23 x 30, or cross-sectional area of 690 square inches1 decreases or constricts the shaft opening 40% l have found, however, that a most desirable arrangement is provided by utilizing three plates or leaves, in which the plate il provides a constrictionpf 80%, vtheplate i8 a constriction of 60% andfthe. lplateaii a constriction oieC/b. Such an arrangement has been found highly effective in maintaining high melting zone pressures.

Cupolas ordinarily operate at an averagfpressure of about l pound per square inch, Ybut by means or" this method of constructingthe shaft area, operating pressures canfhe increased-to2, 3 and 4 or more pounds per square inch.

When not in use, the plates i?, i8 andiszare stored in the recess il othe cupola, with their upper edges;-. resting"l against` the inclined back wall i6, in which-open.positiongthe plates are inclined-.andy cannot: be dislodged g unless pulled forwardly, 4as by-,.-mea-nsof a: hooked rod inserted through-the'. opening i0 :and into an opening 2l adj-acentfthe-upper edge oifeach plate. In order to insure,y against :accidental Ydislodgnient oi the p latesdil,` isandnl, as fonder certain operating conditions oi the cupola. in which a strong suctionpinayv befcreetedlnfthe recess H, a latch niemberlw (Figs: l-and-2) is provided, which' extends .through the side Wall i5 and may be slid to the plate-latchingposition shown in solid lines in Fig; 2,-k orh to the positionindicated by the brokendinesdn Fig. 2, in which latter position, theplates may-be pulled forwardly.

As each-,plate*is-pulledgforwardly, it falls by gravity to the operative, closed, or horizontal position shown in broken lines in Fig. l, inwhich position, the plates are supported by brackets or stops 22 eXtend-inginward-ly from the walls of the cupola. When all-.of the plates are in operative position, only the plate i9 is eective to constrict the cupola area, sincethe,openingy in this plate is-smaller than the openings in the other plates. When only the plates :I1 and IB Vare in horizontal position'. only the -plate 8-is effective to constrict the cupola area, since the-opening in this plate is smaller than the opening in plate Il.

The-cupola may bev charged either before any oftheplateshave been moved into operative position, ormay-vbe. charged by dumping or raking the raw materials through the openings in the plates while the plates are in; operative position. To lfacilitatesuch charging through; the openings, the openngsmay, ifdesired, be provided'with inclined downwardly extendingv sides forming hoppers, it being understood, however, that this latter expedient serves to further constrict the openings which additional restriction must be compensated fonby making the openings larger.

When using mechanical charging devices, motor-drivenblades can be used to push the raw materials fto theleaf or `blade hoppers.

It` isthus seen'that, l;have provided .a means of veiectivelyV providingI for uniform distribution of air through` a -cupolaf charge, that isl to say, for thepressurizing of cupolas andrthat the means which I have 4provided forthis Apurpose is of extremely simple construction and -relatively inexpensive -to install.

Although the aforesaid-pressurizing means has been designed particularly for use or incorporationin a cupola ofrectangular design, as shown in -my aforesaid patent, it, is to be understood 4 that the principle of the invention can also be incorporated, by suitable modification thereof, in cupolas of circular or conventional design.

In Figs. 4, 5, 6 and '7 of the drawings, there is illustrated a modification of the invention, in which the back Wall of the cupola is not modified, as in the previously described construction, but instead, a plate 23 is provided of substantially the same exterior dimensions as the shaft of the rectangular cupola.

The plate Mis-provided with spacedpairs of openings 24 and 25, each pair of openings being adapted to be completely closed by means of rectangularfclosure plates 26 which are connected to each other as by a connecting arm 21. The arm 21 -is guided for slidable reciprocal movement ina-guidemember 28, which is secured to the plate 23. To further insure rectilinear movement of plates 2B, guides 29 are secured to the plate these guides having portions 35 which abut the sides-edges of the plates 24..

The plates 26 are movable from lthe solid' line position shownin Fig. 4, in which position the openings 2li-and 25are completely closed, to the broken line position` shown in this gure, in which theopenings 24 and 25 are completely open.

Byniovernentof one or both pairs or `the plates 26 to selected positions between the aforesaid completely closedv or completely open position, an almost .-innite variation in the area or size of the air passageways throughy ythe plate 23 may he attained, for pressurizing purposes.

The-plate 23is also provided at one edge with a flangeprlipr-ll, of arcuate cross-section, the` function of which-will hereinafter appear.

The plate 23-is rigidlysupported upon a shaft- 32 -whichfextendsthrough the Yend walls of the cupola.- This shaft mayberotated,` as byv areversing motor.33 to quickly rotate the'p-late 23,

in a clockwise direction, as viewed in Fig. 5, frein the-operative position shownin Fig; 5 to the position shownK in broken lines in this gure.

For the-purpose of locking or maintaining the plate 23in the solid line position shown in Fig; 5,

spaced dogs or latching elements Bilanci 35 are provided, which are pivoted, as at 3S, to thelower edge 8 of the charging -opening i0. These dogs or'ilatching elements normally underlie the forward edge. portion of the plate, while the rear edge of the plate rests on ledgesor stops 3l extending inwardly into thevcupola shaft-from the rear wall of the cupola.

In ,orderto permit the plate 23 to be rocked or oscillated to the broken line position showz-if in Fig.Y 5,-Ihave provided means, inthe form ota reciprocable rod 38,-having slots 39 through which portionsof the'dogs 34 `and-'351 extend, the dogs having arcuate slots-40, through which pins di extend,l and pins 4I extending diametrically throughA the rods and being-riveted to the latter.

The rod 38 is adapted to4 be reciprocated-'hy an air cylinder,"diagrammatically represented at 42 (Fig. 4), which cylinder may, for example, he

of the type known as aBellows airrnotor.

In onedirection -of movement of the rod 38,

the dogs 34-and v35 ,are brought into underlying relationship with the forward edge of the platelfi.

while in the other direction of movement, thedogs are withdrawn fromJ such relationship, permitting the-plate23 to be moved to the position shown` in broken lines in Fig. 5.

Afterthe openings in `theplate 23 have been adjusted to` predetermined size, the cupola may be charged by discharging the raw materials onto -the plate while in the solid line position shownV in Fig. 5. After each loading of the plate 23, the dogs 34 and 35 are released and the plate quickly rotated to the broken line position shown in Fig. 5, the stops 31 acting to prevent rotation of the plate through more than 180 degrees. This causes the raw materials to be dumped from the plate into the shaft, and upon completion of the dumping, the plate is quickly rotated in a counterclockwise direction to the solid line position, ready to be again loaded.

It will be noted that in the course of rotation of the plate 23 from the solid line position shown in Fig. 5, to the broken line position, it passes through a position in which it is disposed vertically, i. e., at a position of 90 clockwise from the solid line position as viewed in Fig. 5` In the solid line position, which may be termed the closed position, the plate 23 at least partially obstructs charging of raw materials into the shaft, depending upon the extent to which the plates 26 have been moved over the openings 24 and 25. In the 90 position, to which I have referred, which may be termed the open position, the plate 23 has virtually no obstructive effect, insofar as passage of raw material into the shaft is concerned.

The flange or lip 3l prevents the raw mate-t rials, as they are dumped from the plate 23, from dropping too quickly, which might cause undesirable piling of the materials at one point or side of the cupola. In other words, it tends to cause more uniform distribution of the dumped raw materials.

After the cupola has been charged, the plate 23 is returned to its solid line position, where it is ready for its pressurizing function.

In order to avoid interference with the rotary movement of the plate 23 as well as to provide for a more economical construction, the refractory lining of the four Walls of the cupola may be replaced with cast iron block or formed of Welded sheets of stainless steel or Inconel for a distance extending approximately two feet above and below the charging opening. Thus a maintenance problem is substantially avoided and the possibility of refractory becoming dislodged and interfering with movement of plate 23 is also avoided.

By the use of pressurizing means or devices of the character described, I am able to use relatively high air pressures in the combustion zone of the cupola, thereby providing improved combustion, hotter iron, increased melt per square inch of cupola cross-sectional area, greater fuel economy and more uniform operation of the cupola, and to avoid or minimize bridging of the cupola by slag.

It is to be understood that the forms of my invention, herewith shown and described, are to be taken as preferred examples of the same, and that various changes in the shape, size and arrangement of parts may be resorted to Without departing from the spirit of my invention, or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. In combination with a cupola shaft, means for pressurizing said shaft, said means comprising at least one plate within the shaft having an opening therein of lesser area than the internal cross-sectional area of said shaft at the level at which the plate is disposed, said plate being pivoted about a xed horizontal axis and movable from a closed position in which it partially obstructs charging of raw materials into the shaft to an open position.

2. The combination, as defined in claim 1, in which said shaft is of rectangular cross-section, and said plate is of corresponding rectangular crm.

3. In combination with a cupola shaft as claimed in claim 1 in which there is provided, means for selectively pressurizing said shaft at different air pressures, said means comprising a series of plates having openings therein, the openings being graduated in area as between the different plates.

4. The combination, as defined in claim 3, in which said plates are movable from a closed position in which they partially obstruct charging of raw material into the shaft to an open position in which they have no obstructing effect.

5. The combination, as dened in claim 4, in which said shaft is of rectangular cross-section, 21nd said plates are of corresponding rectangular crm,

6. In combination with a cupola shaft of rectangular cross-section, one wall of said shaft being fo-rmed to provide a recess and means for selectively pressurizing said shaft at different air pressures, said means comprising a series of plates having openings therein, the openings being graduated in area as between the different plates, said plates being movable from an inoperative position Wholly within said recess to an operative horizontal position transversely of said shaft.

7. The combination, as defined in claim 6, in which said plates are mounted for pivotal movenent between operative and inoperative posiions.

8. The combination, as defined in claim 1, in which means are provided for supporting one edge of said plate when in operative position, and other means are provided for withdrawing said supporting means when it is desired to move said plate to inoperative position.

9. The combination, as dened in claim 8, in which said shaft is of rectangular cross-section, and said plate is of corresponding rectangular orm.

10. In combination With a cupola shaft as claimed in claim 1 in which means for pressurizing said shaft are provided, said means com- Drising a plate having a plurality of openings therein, and means for varying the effective area of said openings.

11. The combination, as defined in claim 10', in

which said plate extends transversely of said shaft and is movable about an axis diametric of said shaft, whereby the plate may be used to dump materials charged thereonto into the shaft.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 635,652 Canavan Oct. 24, 1899 1,068,237 Gorr July 22, 1913 1,435,610 Koch Nov. 14, 1922 1,872,057 Boegehold Aug. 16, 1932 2,471,776 Reece May 31, 1949 FOREIGN PATENTS Number Country Date 16,484 Great Britain Sept. 14, 1901 OTHER REFERENCES The Foundry, Sept. 1950, page 127.

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