US2908737A - Smoke suction installation for electric metal melting furnaces - Google Patents

Description

Oct. 13, 1959 G. DE DOMINICIS SMOKE SUCTION INSTALLATION FOR ELECTRIC METAL MELTING FURNACES 5 Sheets-Sheet 1 Filed Feb. 8, 1957 Dill! Oct. 13, 1 5 6. DE DOMINICIS 2,998,737

SMOKE SUCTION INSTALLATION FOR ELECTRIC METAL MELTING FURNACES 5 Sheets-Sheet 2 Filed Feb. 8, 1957 Oct. 13, 1 59 G. DE DOMINICIS 2,908,737

SMOKE SUCTION INSTALLATION FOR ELECTRIC METAL MELTING FURNACES Filed Feb. 8, 1957 5 Sheets-Sheet 3 Oct. 13, 1959 DE D (118 2,908,737

G. SMOKE SUCTION INSTA N ELECTRIC METAL MELTING FURNA Filed Feb. 8, 1957 5 Sheets-Sheet 5 United States Patent SMOKE SUCTION INSTALLATION FOR ELECTRIC METAL MELTING FURNACES Giovanni de Dominicis, Milan, Italy Application February 8, 1957, Serial No. 639,080 8 Claims. (Cl. 13-

The present invention relates to smoke exhaust installations and, more particularly to installations for electric metal melting furnaces.

With particular reference to the type of electric furnace having a crucible mounted to oscillate on supports and having a cover rotating on the vertical axis of the crucible in which two orifices are provided (one for the tapping of the furnace and the other for the discharge of slag), it is a known fact that the exhausting of fumes involves considerable difliculty.

In fact, since the fumes must be exhausted while the furnace is working and since, during operation, the crucible is caused to oscillate, many technical and functional difliculties have to be overcome.

For instance, in heretofore known installations, a cover may be provided with a suction duct by means of which the'fumes are drawn off and, as long as thefurnace has its geometrical axis in a vertical position the exhaust installation generally works fairly satisfactorily.. This is, however, not a satisfactory arrangement when the furnace is tilted, because the suction piping, being rigidly fixed, cannot follow the motion of the cover. Furthermore, the connecting of such suction piping is not a simple matter.

It is an object'of the invention to insure, under all circumstances, the perfect exhaust of fumes, and at the same time to provide an installation of simple construction. It is a further object of the invention to provide for exhaust while allowing the associated furnace to move freely in the tapping and slag discharge phases, and while also permitting. a ready maintenance of the furnace itself.

These and other objects of the invention are achieved by an installation which is essentially characterized by the fact that, on each side of the furnace in correspondence with the tapping. spout and the slag discharging orifice, and also in correspondence with the electrodes, an exhaust hood and orifice are provided. The fumes are drawn through respective ducts connected to an exhaust manifold, so designed as to follow the motions of the furnace during. the phases. of tapping and slag discharge, but remaining constantly connected to the aforesaid hood and orifice, the manifold being in turn connected. to a vacuum inducing fan or the like. ':In order to permit maintenance work on separate furnaces without'hindrance to the various operations by the exhaust installation, the duct of each pair of installations, consisting of a hood, and orifice, is swivel mounted and connected to a header acting as a fumes collecting chest, from which collecting and discharge ducts branch out'so as to' leave the furnace free and to permit rotation for the loading phase and to allow access to the furnace for maintenance work.

Due to the oscillation of the furnace with respect to the sides on which the tapping spout and the slag discharging orifice are located, a variation of distance with reference to the fixed parts takes place, and therefore the collecting duct is telescopic so as to be able to adapt automatically to the axial variations which take place 2,908,737 Patented Oct. 13, 1959 along the duct itself and to allow furnace in its cradle.

In accordance with one embodiment of the invention, each hood and its corresponding suction orifice are made intercommunicating through a conduit. The free end of which is mounted, for oscillation in a horizontal plane with respect to the geometrical axis of the furnace, on a corresponding end of the collecting header firmly fixed to the outer shell of the crucible and having the possibility of rotating about a horizontal axis and therefore in o vertical plane in correspondence to its connection orifice with the telescopic collecting conduit. This latter conduit in turn is so designed as to be able to rotate about the lower connecting fitting with the piping abutting the fan.

The collecting conduit is advantageously formed by two end elbow fittings, each of which at one end have a flange, while the opposite end isconnected to two lengths of a conduit inserted one inside the other in a telescopic fashion, the portions of conduit connected with the elbow fittings being mounted so as to swivel about associated swivel pins mounted on suitable supports, the latter being respectively integral with the crucible and to the collecting manifold connected with the fan.

The invention will next be more fully described with reference to the accompanying drawings wherein:

Fig. 1 is a diagrammatic view in elevation of an electric furnace with an exhaust installation according to the invention;

Fig. 2 is a view taken along line 2-2 in Fig. l and shows the furnace in its normal position;

.Fig. 3 is a top plan view of the structure shown in Fig.

free movement of the Fig. 4 shows the furnace phase;

Fig. 5 shows the furnace charging phase;

:In Fig. 6 is shown an enlarged cross section along line 6-6 in Fig. 2;

Fig. 7 shows a cross section of the collection manifold in .Fig. 6; and v Fig. 8 shows the cross section of the flange of the collection manifold, taken along line 88 of Fig. 6. p

In Figs. 1 and 2, a pivotable crucible a having a cupola b is mounted so as to oscillate byvmeans of two curved slides 1 which are integral with the crucible and which run on the corresponding slideways 2, these means being conventional.

The furnace is equipped with a spout 3 for tapping and with an orifice 4 for slag discharge, as well as with electrodes 5, 6 and 7 (Fig. 3), all of these parts also being conventional.

In order to exhaust the fumes produced by the furnace and in correspondence with the tapping spout 3 and the slag discharge orifice 4, exhaust hoods 8 and 8a and orifices 9 and 9a are provided on opposite sides of the electrodes 5, 6 and 7. These elements are so positioned because the fumes usually originate in proximity to the electrodes. The elements 8 and 9 and 8a and 9a lead, respectively, into a conduit 10 or 10a, the ends 11 and 11a of which lead in turn into the branches 12 and 12a of a collecting head '13. I I

The conduits 10 and 10a are hinged at their ends 11 and 11a on'.pins 14 and 14a (Figs. 1, 2 and 3), and the branches 10 and 10a are supported by uprights 15 and 15a in brackets 16 and 16a.

.The collector 13 (is supported by two members 17 integral with crucible a.

The collector 13 is connected to an elbow 18 in such a manner as to render them mutually free to turn about the geometrical axis x-x of the axle 19 (-Fig. 6) which acts as a support, the collector 13 being fitted with an annular flange 20 in which a corresponding flange 21 on position during the tapping position during the slag diselbow 18 is free to "rotate. This permits relative movement of the whole furnace with regard to the elbow 18, the axle 19 being fixed at one end 22 in a boss 23 in the collection header 13 and at its middle part 24 by bearings 25 and 26 supportedbyspokes 25a and 26a on head 13 and elbow 18, while the other end 22a is free to turn on support 27 which is integral with the elbow 18.

The end 18a of the'elbow 18 terminates at 28a from which extends a vertical branch 28 inserted telescopically in piping 29 fixed firmly to another elbow 30.

' This elbow 30 is at the same time engaged by an annular flange 31 with a corresponding internal flange 32 of piping 33, the branch 34 of which is connected through its end 35 to a fan (not shown in the drawing).

'To guide the two sections 28 and 29 for mutual sliding (Figs. 3 and 4), guides consisting of a pair of rods 36 are provided. These rods are secured to the elbow 18 and are free to slide between pairs of rollers 37 fixed to the section 29 (see also Figi 7).

vA supporting pm or axle 38 is provided for the elbows 30 and'34 in which are mounted sleeves 39, 40, 41 and 42 which position the supporting pin 38, the sleeves 39, 40, 41 and 42 being supported in turn by members including spokes a and 41a (Figs. 6 and 8) on members 30 and 34. The pin 38 turns in bearings 45 and 46 on a base 47.

[in operation, the furnace, having been charged and the metal melted, is tilted by means of the rod 48 (Fig. 2) actuated by a hydraulic cylinder 49 and reaches the position shown in Fig. 4 for tapping. During this phase, the collector dust, i.e. the assembly consisting of the two elbows 11-8 and 33 and the connecting lengths 28 and 29 of these latter, makes a partial rotation 1 with respect to the vertical plane V, a constant connection between the pipes being assured due to the telescopic system of' mounting.

Similarly, for passing on to the slag discharging operation (Fig. 5), the constant connection between the pipes is insured, and consequently a perfect efiiciency of the installation results. 1

As may be best seen in Fig. 4, the geometric axis of symmetry G of the'collecting duct is at an angle with reference to, the vertical and is displaced towards the tapping-side in order to obtain almost equal sliding motions of the telescopically mounted pipes 28 and 29. In other words, when the furnace is caused to turn for the tapping phaseand also when it is tilted the other way for the slag discharging operation, the movements of the tubes one inside the other is practically equal.

Although one embodiment of the present invention has been described, it is to be understood that in practice various other forms may be possible without departing from the scope of the invention.

' What is claimed is:

i 1;A11 exhaust installation, for a furnace having a pivotable crucible with diametrically opposed tapping and slag discharge means, comprising exhaust hoods independent of and at opposite sides of the crucible for exhausting fumes therefrom, conduits coupled to said hoods for leading away the fumes, a collecting head for collecting the fumes from saidconduits, means coupling the conduits to said head and permitting movement of the conduits relative to the head so that the hoods can be guidably displaced from the crucible to permit a pivoting thereof for tapping and slag discharge operations, and a further conduit coupled to said head for the exhaust of fumes therefrom and including telescopic tubular elements'whieh adapt said further conduit for axial adjustments required by the tapping and slag discharge operations.

2. An exhaust installation, for a furnace having a pivotable crucible with diametrically opposed tapping and slag discharge means, comprising exhaust hoods inde- ,pendent of and at opposite sides of the crucible for exhausting fumes therefrom, conduits coupled to said hoods for leading away the fumes, a collecting head for collect: ing the fumes from said conduits, means coupling the conduits to said head and permitting movement of the conduits relative to the head so that the hoods can be guidably displaced from the crucible to permit a pivoting thereof for tapping and slag discharge operations, and an elbow coupled to said head for the exhaust of fumes therefrom, said elbow and head each including mutually engaged means enabling a rotation of said elbow on said head for facilitating the said operations.

3. An exhaust installation, for -a furnace having a pivotable crucible with diametrically. opposed tapping and slag discharge means, comprising exhaust hoods independent of and at opposite sides of the crucible for exhausting fumes therefrom, conduits coupled to said hoods for leading away the fumes, a collecting head for collecting the fumes from said conduits, means coupling the conduits to said head and permitting movement of the conduits relative to' the head so that the hoods can be guidably displaced from the crucible to permit a' pivoting thereof for tapping and slagdischarge operations, and a conduit coupled'at one end to said head for the exhaust of fumes therefrom, an elbow at the other end of the latter said conduit, and a support for supporting said elbow for rotation about an axis whereby said head and hoods can be pivoted with said crucible. 4

4. An installation as claimed in claim 1 comprising external guide means on said' further conduit for the guiding of said telescopic elements.

7 5. An installation as claimed in claim 2 comprising a telescopic conduit coupled tosaid elbow, and a further elbow coupled to said telescopic conduit, said elbows defining spaced and parallel axes, exhaust means, and means coupling said elbows respectively to said head and said exhaust means for rotation on said axes. i

6. An installation 'as' claimed in claim 5 comprising axles in said elbows and extending respectively into said head and exhaust means, bearings for the axles and spokes supporting said bearings in said .elbows,.head.and exhaust means. I f r i 7. An installation as claimed in claim 6 comprising flanges on said elbows and telescopic conduits for the engag'ement of the same and further flanges on saidelbows, head and'exhaust means for the rotatable "engagement of the same. V

8. An installation as claimed in claim 7 wherein said exhaust means comprises a fan and a conduit operatively associated therewith and coupled via said elbows and telescopic'conduit to said head. i i

I References Cited in the file of this patent Switzerland Sept. 1, 1938

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