US2303657A - Cupola - Google Patents

Description

Dec. l, 1942. J. R. PARSONS CUPOLA Filed .June 1o. 194s:

Patented Dec. 41,' 1942 OFFICE Joseph R. Parsons, Chicago,

United States Gypsum Comp a corporation of Illinois Application June 10,1940, serial 10.339595 rn om April 15, 1940 4 Claims. This invention relates to a cupola, and has nl., mimm-l to Chim, Ill.;

(Cl. 26S-38) for its primary object the provision of' a newy andimproved cupola and discharge-means for producing a substantially steady flow of a melt from which rock wool, mineral wool, or glass wool may be formed.

Cupolas have long been employed as means for melting metals and mineral substances. They have not proven entirely satisfactory for all purposes, however, particularly when 'the cupola is used for melting mineral material used for the production of mineral wool. The standard practice in cupola operation is to extract the melt from the side of the cupola at a point near the 'bottom 'Ihe undesirable results of this lpractice have been, at least two-fold. In the ilrst place. the melt accumulating in the bottom of the cupola remains in contact with the fuelunf. dergoing combustion and has a tendency to absorb excessive amounts of carbon from the fuel bed. 'This is particularly undesirable when the cupola is used to produce a mineral melt which the product is undesirably darkened by the carbon. Secondly, 'the path of ilow of the melt from a hole positioned in the side of the cupola is usually longer than desirable and the melt is chilled to an excessive degree, particularly if the of the cupola.k An outlet formed in the side walls of the cupola also may result in a variableow of melt, since the flow maygbe diminished or even stopped if it shouidchill' within the spout.

V/movable tap hole is blown to `a mineral wool` product, ,because melt must pass through water-cooledtside walls Under such circumstances, it is necessary to increase the temperature ofthe melt, which is also undesirable, since increased heat in' the melt increases its capac fuel bed.

It is, therefore, one object of the present invention to provide a cupola in which the aboveindicated undesirable-features have been elimhinted. In accordance with this invention, a

ty to absorb carbon from the cupola is provided in which the melt is removed from the cupola substantially assoon as it is formed. 'I'he amount of carbonrwhich it absorbs from the combustion chamber is, therefore, markedly reduced.

The present invention has for a further object the provision of la cupola.` which has a'tap hole or tap holes through which the rate ofdischarge of the melt from the cupola may be adjusted and uniformly controlled. The tap holes are so constructed that the melt passing therethrough does Y not have a tendency to chill, and therefore a constant flow of melt from the cupola is insured.

melted, fuel, and ldagen-continuing gases are introduced, a tap holel positioned ladjacent the bottom' of the chamber for\ removing the melt substantially as rapidly as it is formed, and a plate positioned adjacent the bottom of the cupola, said plateI having an orifice which registers with said tap hole for the purpose of controlling the amount of melt passing therethrough. l, The tap hole plate positioned adjacent the bottom of the cupola is adjustable and may contain a plurality of orifices, each of which is adapted to be registered with a corresponding 'tap hole in the bottom of the cupola-and each of which may be of a different size, so that any predetermined flow of melt may be obtained from th cupola. Furthermore the rate of flow may be further regulated by partially closing of! the passageway for the escaping melt byl moving the tap hole plate to a slight degree so that the tap hole and plate orice are'no longer in full register. The amount of melt flowing through any one orifice, therefore, may be readily adJusted. 'I'he tap hole plate is so constructd that. when it is in the desired position, the amount of melt flowing through the orifice remains substantially constant, the melt does not solidify around it, `and it is unnecessary for an operatorto give the cupola and the. flow therefrom continuous attengtion.

In accordancewith a further embodiment of this invention, acupola is providedwhich has comes `.unduly darkened. 'I'he bottom of the of tap holes, each of which is situated in the lowermost por'- cupola is provided with a numbertion of one of a plurality oi' depressions positioned in the bottom of the cupola. Each of the depressionsis separated from the others by means of a conduit positioned adjacent the bottom of the cupola., through which a cooling fluid may be passed. During the operation of the cupola,

Vthe cooling effect produced by the conduit causes a certain amount of slag to solidify adjacent thereto, thus building upa` ridge portion between the depressions and permitting the molten material to flow yout through the tap holes positioned in the lowermost portions thereof. If desired., tap hole plates with orifices, previously indicated and hereinafter more fully described,-

may be positioned adjacent each one of the tap holes for regulating the rate of flow of melt from each tap hole.

When the cupola is employed for melting mlneral material for the production of mineral wool,

the'end of a blowpipe is positioned below the tap hole so that the melt falls into a high velocity stream of steam or air whereby the mineral wool is formed. A chamber is providedfor collecting the resulting mineral wool fibers. In a mineral woolblowing apparatus having a cupola with a plurality of tap holes, a number of blowpipes are provided equal to the number of tap holes, whereby the melt from each of the holes is blown by each blowpipe into the mineral wool collecting chamber. It is preferable that the tap holes be staggered somewhat so that the blowpipes below the cupola may be positioned in the same plane and all blow the disintegrated melt stream in a single direction into a single mineral wool collecting chamber.

For a more complete understandingof this invention, reference will now be had to the drawing. in which:

Fig. 1 is a diagrammatic elevational view, taken partially in section, showing a cupola associated with a mineral wool blowing and collecting chamber constructed in accordance with one embodiment of this invention;

Fig. 2 is a bottom view of the cupola taken along the line 2-2 of Fig. 1;

Fig. 3 is a cross sectional'view of the cupol taken along the line 3 3 of Fig. 1;

Fig. 4 is a plan view of a tap hole plate that may be used with a bottom discharge cupola constructed in accordance with one embodiment Jof this invention;

Fig. 5 is a cross sectional view of the tap hole plate taken along the line 5-5 of Fig. 4;

Fig. 6 is a detail view of the bottom portion of a modified form of cupola having two bottom discharge tap holes;

Fig. '1 is a cross sectionalfview of the modified cupola taken along the line 'i-I of Fig. 6;

Fig. 8 is similar to Fig. '1, but shows a cross sectional view of the bottom of a second modified form of cupola having four tap holes; and- Fig. 9 is an enlarged sectional view through one of the tap holes of the cupola.

Referring now more particularly to Figs. 1 through 5, a cupola'is provided having an outer side wall l0 and an inner side wall I2 which co-operate )to provide a cooling water jacket I4 completely surrounding the sides of the cupola. Cooling water for the water jacket is introduced at the lower end of the jacket through an inlet pipe I6 and is withdrawn atr the top through an outlet pipe I8. As shown, the cupola is provided with an unjacketed sheet metal bottom portion 28 which may be protected from direct contact with the melt formed in the cupola by means of In a central portion of the bottom of the cupola a tap hole 24 is provided whose edges are protected by a collar 28 of refractory material. The

secured to the bottom plate 20 in any desired manner. The tap hole plate 28 has one or more orifices 32 which are positionable by sliding the plate 28 on the brackets 20 to register with the tap hole 24. Suitable handles or engaging means 34 are provided on the tap hole plate 28 so that the tap hole plate may be engaged by a suitable tool to position 'the plate so that. one or the other of the orifices may be brought into registry with the tap hole 24 in the bottom of the cupola or to move an orifice out of full registry with the tap hole whereby the rate of flow of. melt from the bottom of the cupola is diminished to the desired extent. The flow of melt from the cupola thus may be regulated by providing a 'plurality of different size orifices in a single plate or by adjusting the relative positions of the orifice 82 and the tap hole 24 with respect to each other.

In accordance with one embodiment of this invention, as more particularly shown in Fig. 5.

the orice 32 in the tap hole plate 28 has a countersink 36 which is preferably on that surface of the plate away from the tap hole 24 whenA the plate is in position adjacent the bottom of the cupola. The tap hole plate 28 is thus somewhat thinner adjacent the orifice 32 and the melt keeps the metal surrounding the orifice l2 at a sufficiently high temperature to prevent the melt from solidifying adjacent the orifice. Consequently, the effective size of-the orifice 82 remains substantially constant in diameter at all times and periodic cleaning of it to break out any solidified slag becomes'unnecessary. The metal tap hole plate 28, however, is sufficiently thick- `so that a certain proportion of the heat imparted by the melt to the plate adjacent the orifice 32 is conducted away from the Iorifice and becomes dissipated; This is desirable because, if some means were not provided for dissipating this heat,

the side walls of the orifice 32 have a tendency .to mlt, thus increasigglthe volume of melt flowing therethrough. The -countersink 88 adjacent the orifice 32 is of such size and shape that it permits the metal adjacent the orice to be maintained at a sufficient temperature toprevent the melt from solidifying in the orifice, but. on the other hand, permits a sufficient amount of heat to be conducted away from the side walls of the orifice, whereby melting of the plate is prevented.

It has been found that a suitable tap hole plate may comprise cast iron. However, any other material maybe employed which will withstand the temperature to which the plate is heated during opera-tion of the cupola. A cast iron plate having an orifice with a diameter of 3/4 inch. i inch, or 11A inches may suitably be about 6 inches square and '1,/2 inch thick. The-countersink for a 1-inch orifice maybe about 21/4 inches in diameter adjacent one surface of the plate and have uniformly converging side walls extending into the plate and terminating about inch from the opposite surface of the plate, as indicated (on a reduced scale) in Figs. 4 and 5. It will, of course, be clearthat the various dimen- 2,303,657 sions of the tap hole plate, the orifice, andthe f.

,countersink maybe variedy in relation to each other within wide` limits .to Vp'roducv the desired lresult, particularly fwhe'n aplurality of orifices are provided in the plate. as previously indicated. vThe endofthe blowpipe,, positioned underneath the tap hole 2,4 and orifice registered therewith, blows a stream of steam or air at high velocity athwart the falling stream of melted material to disintegrate the same, thereby formingthe mineral wool 42 which is collected' in a suitable settling chamber 44.

The fuel for producing the melt and material to be melted vare introduced into the top of the cupola through an opening 46 which is opened and closed by a vertically movable plunger 48. As shown, a funnel-shaped structure 50 formsthe top of the cupola and provides the side walls of a hopper into which maybe placed the fuel and mineral material prior to the time that it is introduced into the cupola by depressing the plunger 48. The fuel and mineral material are introduced into the cupola through the opening 46 in the form of briquettes which may be formed by intimately mixing comminuted mineral mat-A ter and solid -fuel with'a binder and pressing the mixture, whereby the desired briquette is formed,

"The oxygen-containing gases, such as air, for` promoting combustion of the fuel in the cupola are forced into the cupola by means of anelectrically motivated fan 54 through a conduit 55 and a wind box 55 .which surrounds the lower` side walls of the cupola. A plurality of apertures 58 provide passageways for the air from the wind box 56 to the inside of the cupola.' 'I'he gaseous products of combustion escape through a suitable nue or chimney Sil.

It is `clear from the foregoing description that the fuel is ignited in the cupola, and the air introduced through the wind' box 56 and the openings 58 promotes rapid combustion of the fuel to heat the interior of the cupola to temperatures sunlcient tov melt the mineral material compounded` with th'e fuel in the briquettes 52. The melt thus formed flows to the bottom of the cupola out through the tap hole 24, through the oriilce 32, and at a steady rate into the stream of rapidly moving steam or air discharged from the blowpipe, whereby the meltis drawn out into mineral wool fibers and projected into the settling chamber 44. The vohime rate of discharge of themelt may be controlled by proper positioning of the tap hole plate as previously indicated.

Referring now more particularly to Figs. 6 and 7, -a cupola is shown which contains a bottom of the cupola. Consequently, the fluidity of the melt is not impaired by the presence oi' the dividing cooling conduits $2, and a means has been provided for withdrawing a plurality of molten streams from a single cupola. .,A pair of blowpipes Ila and 38h are provided below the tap holes 24a and 24h for blowing the melt into a mineral wool chamber if such is desired.

Fig. 8 shows a construction in winch the bottom of a cupola is divided into four sections or depressions having a tap hole positioned in the lowermost portions of each and which depressions are separated one from the other by means of cross# ing cooling conduits 66 and 68 which have a function similar to the conduit 82 previously 4described in connection 'with Figs. 6 and 7. The tap holes positioned in the bottom of the vdepressions plate increasing of the, cupola constructed in accordance with Fig.

8 are staggered somewhat so that the blowpipes positioned below the tap holes lie in the same plane and are directedin the same direction so that all of the mineral wool formed thereby is 1 directed `into a single mineral wool collecting chamber.

It will be clear fromthe above description that a construction has been provided which has many desirable features not inherent in any of the devices of the prior art. While the cupolas specifically described above are those in whichfthe melt is formed directly within the combustion chamber of the cupola, other types of cupolas and melt for-ming furnaces are also included within the scope of this invention.

While several particular embodiments of this invention are shown above, it will be understood, of course, that the invention is not to be limited thereto `since many modifications may be made, and it is contemplated, therefore, by the appended claims, to cover any such modifications as 'fall within the true spirit and scope of this invention.

I claim: 1.1 In a cupola for the manufacturew of glass woo for continuously forming melt therein and continuously discharging said melt at a high temperature through a taphole in the bottom of said cupola, a tap tap hole and having a corresponding tap aperture through a relatively thin portion of said plate. to form a thin edge wall aroundsaid aperture, vsaid in thickness outwardly and downwardly from said aperture to provide an obtuse-angle conical depression substantially on the axis-of said aperture so that the said increasportion having a pair of tapholes-positioned in The ridge portion is permanent and does not have a tendency to corrode away, since the slag always provides a solidified portion adjacent the cooling conduit I2. The cooling conduit, however, does not exert auch a great cooling effect on the melt being produced in the cupola as to ail'ect its portion I4 between the two tap holes 24a and 2lb.

conical depression said aperture so\that the said increasing thickilowability through the tap holes in the bottom 76 ing thickness portion of said plate has a heat conducting capacity capable of maintaining said thin edge wall below its melting temperature but above a chilling temperature of the issuing melt.

wool or the like comprising a melting chamber for continuously forming melt therein and continuously discharging said melt through a tap hole in the bottom of said cupola, the combination with'. a refractory lining for said tap hole,l of a metal tap plate positioned snugly'under said lined tap hole for slidable registration therewith, said plate having a corresponding `tap aperture through a relatively thin portion of said plate to forma| thin edge wall around said aperture, said plate'increasing in thickness outwardly and downwardly from said aperture to provide an obtuse-angle substantially on the axis of ness portion of said Y e platehas a heat conducting capacity capable of 2. In a cupola for the manufacture ofsglass.v

maintaining said thin edge .or the like and having a melting chamber,4

plate positioned snugly under said wall below its melting temperature but above a chilling temperature of the issuing melt.

3. In a cupola ofthe character described having at least two spaced tap holes through the bottom wall thereof, a cooling conduit extending transversely between said holes closely adjacent the bottom oi' said cupola, a covering of sand orl e one of said tap holes snugly adjacent the bottom of said cupola and having a tap aperture movable into alignment with its associated tap hole, said plate being sumciently'thin at the edge of said aperture and closely adjacent thereto to prevent chilling and solidiiying of the melt in and closely :,aoaes'z adjacent said aperture, ,am plate gradually mcreasing in thickness downwardly and outwardly from said edge over a portion oi its extent so that sumcient progressively increasing heat conductivity is provided outwardly from said edge to prevent melting said edge while simultaneously maintaining said edge at a temperature closely` approaching the temperature of the melt. i

4. In a cupola of the character described having at least two spaced tap holesthrough the bottom wall thereof, a cooling conduit extending transversely between said holes closely adjacent the bottom of said cupola.` a covering of sand or the like in the bottom of said cupola and forming a ridge or elongated mound over said pipe to direct melt to said tap holes, said cooling conduit being ot suiilcient cooling capacity to cause a layer of solidiiied slag to i'orm at least a part of the ridge between said tap holes. A

JOSEPH R. PARSONS.`

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