US2121465A - Smelting furnace - Google Patents

Description

June 21, 1938. c. c. BERG SMELTING FURNACE Filez iAug. 10, 1937 Patented June 21, 1938 PATENT OFFICE SMELTING FURNACE Charles C. Berg, Spokane, Wash., assignor to Beryl Metals Company, Inc., Spokane, Wash.

Application August 10.1937, Serial No. 158,324

2 Claims. (Cl. 266-29) 7 My invention relates to improvements in smelting furnaces and has for an object to provide a smelting furnace adapted for the reduction of ores having a multi-metallic content.

Jinother object of my invention is toprovide a smelting furnace in which multi-metallic ores .may be smelted and during the smelting of which undesired metallic volatiles may be allowed to escape while the volatiles to be saved are caused no to be mixed with air under automatic control and the hot mixture passed and repassed through the smelting ores in the furnace to increase the furnace temperature and form useful new metallic substances.-

)5 Another object of my invention is to provide a 20 the said hot mixture of gases and air and con- A duct it to the tuyeres and also toretain the hot slag till is has cooled.

Another objectof my invention is to maintain the slag adjacent the tuyere openings at tem- 15. peratures above its melting point to provide for it to flow freely therefrom. I

Another object of my invention is to provide clqsable openings in the said annular chamber through which-to view smelting progress and 30 through which to remove the said cooled slag.

Qther objects of my invention will appear as the description proceeds.

I attain these and other. objects of my invention 'with the structure and mechanism illus- 35 trated in the accompanying sheet of drawings, forming a part of this specification, in which Figure 1 is a side elevation of my smelting furnace in section on a vertical medial plane, Fig. 2 is a front elevation of Fig. 1, Fig. 3 is a top plan 40 view of Fig. 2 and Fig. 4 is a bottom plan view of Fig. 2.

Similar characters refer to similar parts throughout. Certain parts are broken away to show other parts hidden thereby.

parts: My furnace, as illustrated, consists of three parts; the upper truncated cone 4, the lower cylinder '1 and the intervening truncated cone 6, all of which are lined with the fire brick 5o 5. The open bottom of the furnace is ciosable by double, hinged doors 8, 8, having the hinges l l the pivoted latch 8 and the catch 8 with which the latch engages to retain the doors in closed position. The top opening 35 is c'losable 55 with the cover 9, lined with the fire brick l0 and With more particular reference to designated intake of the blower not shown.

hinged at 9. The opening 35 communicates with the s'tack-22. The loading opening 35 is closable with the hinged door 31 which is lined with the fire brick 3B and provided with a pivoted. latch to engagearcatch on the furnace wall for retaining the door in its closed position. A by-pass opening ll extends through the furnace wall near its top and has the external thimble 3| with which is connected the downwarly curved pipe 30. Near the bottom of the. furnace are four spaced openings Reach of which, preferably, is lined with a metal thimble or bushing. The openings l2 serve the triple purposesof tuyeres, peep holes and slag outlets. Close to the bottom of the furnace is the molten-metal outlet l3 which communicates with the brick-lined spout 14.

The manifold chamber is annular and surrounds the inverted-truncated-conical part 6 of the furnace wall to enclose the tuyere openings. It is of triangular cross-section, preferably, and has the outer steel plate walls 16 and I1. Both of the walls I6 and I! are welded to the steel plate outer wall of the furnace. Throughthe wall I6 of the manifold are the four' hand holes [8, each of which is opposite one of the tuyeres 12-. Each of the openings'l8 is closable by a door l9 hinged to the manifold wall and fastenable by the pivoted latch 20 'engageable by the catch 2|. of these doors is shown in its open position in dotted lines at l 9' in Fig. 2. An opening 34 in the manifold wall It, preferably disposed midway'between two of the door openings [8, communicates with thepipe 33.

The furnace-is supported on four legs IS the upper ends of which are weldedto the bottom wall ll ofthe manifold. p

The sheave 23 is mounted in bearings on the stack 22 and has the chain 24 placed thereon. The upper end of the chain 24 is fastened on the cover 9 and the lower part is engageable with the notched catch 25 fastened on the furnace wall. A pull on the lower end of chain 24 will raise the cover 9 to its dotted-line position at 9 within the square stack 22, thus uncovering the furnace outlet 35. By engaging the chain with the catch 25, as shown in dotted lines at 24', the cover 9 may be retained in its open position.

The blower 26 has the pulley 2'! over which is laid the belt 28 from-a power pulley not shown. The lower end of the pipe 29 connects with the The downwardly bent pipe '30, fromthe upper part of the furnace, is extended a short distance into the upper part of the pipe 29 which is larger than the said pipe 3|].v The relatively large annu- One lar space II between the pipes II and II provides for the entry of draft air into the pipe 2! around the pipe Ill and the escape of excess furnace gases. The outlet pipe 32 of the blower It connects with the-outer end of the pipe 38, the inner end of which connects with the manifold chamber l6, ll in the opening 34.

In operation: Before charging the furnace, the molten-metal outlet II is plugged with fire clay, a covering of sand is spread over the closed doors I, I and all of the movable parts of the furnace are in their solid-line positions, except the furnace-outlet cover I, which is raised and retained in its open position at l by pulling on the chain 24 and enga ing it at its dotted-line position in the chain catch II at 24'. The charging door 31 is opened, a quantity of coke and multi-metal ores are passed through it and the door is closed. The fuel is ignited and the blower 20 is started. The blower draws draught air through the opening I! and a small part of the products of combustion in the furnace through the pipe 30. But the major part of these gases escape through the furnace outlet fl into the stack 22.

At first the furnace heat releases the morehighly volatile metallic gases which are not desired to be retained. The progress of the process of smelting may be observed at the top of the smelter, where the cover is raised; each of the metallic contents escaping in gaseous form having different and distinct colors. when, to the expert attendant, these colors indicate that the more-highly volatile parts of the metals have been released then the speed of the blower is reduced and, the furnace cover I is closed.

The blower draws draught air through the annular opening 20-, thus tending to form a vacuum at the end of pipe I, to draw the furnace gases through the pipe 30 into the pipe as and force a draft at the tuyere openings i2. Thus the furnace gases, which include the gaseous products of combustion and the said less-highly-volatile metallic gases released from the ores, are mixed in the blower and elected through the pipes 82 and 0! into the manifold Ii, ll, where they are drawn through the tuyere openings II, l2, II, II into the combustion section of the furnace where the hot oxygen unites with the fuel in forced combustion.

The continuous return of the hot gases of combustion through the combustion area of the furnace builds up the furnace temperature till more refractory ores are melted in this furnace than is usual in coke-fired furnaces.

The return of the said less-volatile metallic gases to the surface of the molten metals in the bottom of the furnace at a reduced temperature and in the presence of carbon monoxide, which serves as a reducing agent, results in the union of these gases with the molten metals and the form ing of a homogeneous alloy of different metals.

The continuous flow of hot gases through the tuyere openings i2 maintains the contiguous slag at temperatures above its melting point and thus it freely flows out into the manifold I, II on the bottom of which it cools. Subsequently, the

hardened slag is broken up by hammer blows on the exterior of the manifold bottom and the pieces thereof are removed by hand through the handholes.

Even with the more-volatile metallic gases eliminated from the ores being smelted and with the blower running at a reduced speed, there may, at times, pass out through the pipe 30 a greater flow of furnace gases than will be drawn through the tuyere openings l2. Then a part of these gases will escape outward through the annular draft air inlet-ll into the air. Meanwhile their outward movement through the said air inlet will prevent the passage of draft air into the pipe 20 and into the 'fumace. The ceasing of the supply of oxygen to the fuel, thus caused, will slacken combustion and reduce the creation of furnace gases to a degree which will again allow their entire volume to be drawn into the furnace when draft air will again be drawn through the opening 20- and normal combustion will be resumed. Thus, even with the furnace outlet l0 closed, the smelting process proceeds automatically without the use of control dampers in the said pipes and without considerable attention of the furnace operator.

when the smelting of the ores placed in the furnace is completed, the molten metal is drawn 01! through the spout is by unstopping the outlet ll.

Although the operation of a coke-fired furnace is described above, it is clear that many of the advantages gained by the particular furnace construction disclosed and the smelting process which is made possible thereby may also be ob-.

tained when an electric smelting furnace is used.

Having thus disclosed my invention, what I claim as new therein and desire to secure by Letters Patent is,-

1. smelting apparatus including, a furnace having a by-pass opening near its upper end and a plurality of tuyere openings near its lower end, a manifold enclosing the said tuyere openings having closable hand hole openings, a blower, a

blower inlet pipe having an open outer end, a

furnace outlet pipe having conduit connection with the said by-pass furnace opening and extended into the said outer end of the blower intake pipe providing an intervening annular opening, and a blower outlet pipe having conduit connection with the said manifold.

2. smelting apparatus including, a furnace having a closable top opening, an unclosable bypass opening below and near the said top opening and tuyere openings near the lower end of the said furnace, a manifold enclosing the said tuyere openings, a blower, a blower inlet pipe having an unclosable outer end, an unclosable furnace by-pass outlet pipe extended into the said outer end of the blower intake pipe providingan unclosable space between them for the alternate automatic admission of air into the blower and the exit of surplus furnace gases into the open air, and a blower outlet pipe having conduit connection with the said manifold.

CHAS. C. BERG.

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