Smelting-furnace.

Application filed March 30,1900. (Renewed July 22,1903. Serial No. 168,636. (No model.)

To all whom it may concern:

Be it known that I, Allen R. Partridge, a citizen of the United States, residing at San Francisco, in the county of San Francisco and 5 State of California, have invented certain new and useful Improvements in Smelting-Furnaces, of which the following is a specification.

My invention . relates to the treatment of ores for extracting metallic matters, bullion, io &c., and refers particularly to an improved construction of smelter.

This smelter is especially adapted to carry cut the process of treating ore described in an application for Letters Patent filed upon the 15 same date as the present case and numbered 10,759.

The invention is fully hereinafter described, and is shown in the accompanying drawings, in which— ²⁰ , 1 is a side elevation of the smelter, broken away in parts to show vertical sections. Fig. 2 is a plan view. Fig. 3 is a plan of the portable hearth.

A represents a stack, preferably circular in ²5 section and supported in any suitable way, as by the angle-brackets a and beams J, the latter forming part of some suitable supporting structure. The stack may be constructed of iron and water-jacketed, as shown at a', or can 3° be built of brick or masonry, if preferred.

It is entirely open at the bottom.

B is the charging-door, which I prefer to place at the top, as shown, although this is not essential.

D is an outlet-pipe for the products of combustion, which leads from the side of the furnace near the top. If provision is made for charging the furnace from the side, however, the escape may be through the top of the stack.

I have illustrated the preferred construction.

Holes p p are provided at intervals around the furnace, which may bje opened for the purposes of inspecting and of stirring the charge. . l ^s.^{a wa}ter-feed pipe to the jacket, and O 45 is the jacket outlet-pipe.

Beneath this open-bottomed furnace structure is a hearth C, separated from the furnace, so as to form an open space, which is the draft - inlet' and which extends entirely 5⁰ around. This hearth is preferably a circular casing having an interior refractory lining and¹ bottom o’. At ofie side, near the top, is a slag-spout d, while near the bottom and opposite is another spout, e, for tapping the matte, bullion, or other product, The hearth is pro- 55 vided with a drop-bottom c³ c⁴ for obtaining access to the bottom and lining from below. The upper edge of the hearth cooperates with the. lower edge of the furnace to provide the open draft-space referred to, and in order to 60 control the draft and to regulate the quantity of air admitted I make the said upper edge adjustable toward andfrom the furnace. This can be done in the manner shown by bodily moving the entire hearth toward or away from 65 the furnace, as by the screws f, provided with hand - wheels f', and which .engage with threads formed in the base of the hearth and bear upon some solid support beneath. . It will be observed by reference to, the draw- 70 ings that these screws are independently movable, so that the hearth may be raised equally on all Sides or may be inclined by raising one part more and another less. The purpose of this is to increase or diminish the draft 75 upon one side or the other, as the contents and conditions of the hearth may* require. In addition to a vertical adjustment for controlling the draft-space I find it good and economical practice to make the hearth port- 80 able and entirely removable from below the stack, so as to be interchangeable with one or more others of . like. construction. In this manner I save time and expense in case repairs are needed to a hearth by substituting 85 another. By having the hearth movable I also save time and expense whenever it becomes necessary to blow the furnace in or out in case of the freezing of a charge or the formation of sows or accretions, which are det- 9° rimental to the success of the smelting operation. A track g is laid across the pit, upon which run carrying-wheels c, by which the hearth is portably supported. The screws/ pass through the brackets /* and can bear 95 upon the track-rails or at one side, as shown in Fig. 3, upon any suitable solid part of the track structure. Between the open-bottomed stack and the open-topped hearth a continuous draft-space thus exists, controllable as to 100

S3 757 size and adapted to admit a flow of air uniformly throughout its extent. I attach great importance to this manner of admitting a continuous and undivided volume of air to 5 the smelter instead of using blast or forcing means and twyers which supply the air in separated jets. When the furnace is charged with ore and fuel or with ore alone, which from its nature forms a fuel and combustion io is taking place, a narrow smelting zone is established a few inches above the open bottom, and the air entering uniformly and unbrokenly and without previous heating is immediately exposed to the intense radiated 15 heat from the zone before reaching the latter, and this radiation takes place uniformly throughout the extent of the air-flow, since there are no cross-currents, but only a uniform flow. Thus without previous heating 20 and without expensive mechanical forcing devices I produce a hotter and more effective zone at a considerable reduction in expense.

The necessary draft is produced in my furnace by exhaust or suction operating to.pro25 duce a vacuum in the stack, and I do this by means of a steam-injector operating in connection with an outlet from the stack for products of combustion. Near the upper end of the. structure is the escape-pipe D, which com30 municates with a flue E, which may extend vertically 6r at any angle, provided that it extends across the end of the pipe D. Within the flue E and near its end its inner diameter is reduced by a plug O, which forms an in35 jector-nozzle. A pipe F enters steam-tight through the closed end of flue E, through which steam from any suitable boiler is supplied .and injected through the plug. The steam passes the outlet from the smelter and 40 fills the flue beyond it, and it must always be liberated so as to pass such outlet. The result is that the flue is filled with rapidly-escaping steam, which continues on past the furnace connection and in the flue beyond, thereby 45 excluding air from the flue and drawing gases, &c., from the interior of the stack in the manner of a piston. From the flue the steam passes into the stack, which is larger than the flue, and these successive enlargements of 50 the .steam-passage, prevent any back pressure.

The injector tends to produce a vacuum in the stack, which of course causes a strong inflow of air from below in the manner already described. I may mention here that air under 55 pressure may be used as an injector for creating a vacuum in the stack and producing the draft, and although in such case I should be put to the expense of air-forcing devices I should still obtain an economical advantage 60 over the use of such devices for producing the draft by direct pressure from below. This will be understood by reference to the previous description of the character of the draft in my smelter, which cannot be produced by 65 direct pressure, but can be produced by any ,221 effective means for causing a vacuum in the stack. The flue E may open into the air or may lead to a condensing and dust-precipitating chamber, where fumes and dust carried by the steam are condensed and precipitated. 7°

It is essential to my invention and the successful operation .of the furnace that the junction of the escape-pipe with the flue shall be at a point intermediate between the contracted part in which the Injector is located and 7 5 the discharge end of the flue, so that the blast of steam or air shall impinge against the products of combustion as they emerge from the pipe into the flue. _Q

When the furnace is charged at the top, as °° shown, the escape-pipe D and flue E are practically continuations of the stack, and they are shown in the manner in which I prefer to arrange them. In some cases, however, as in smelters for copper, where it is not desired to 85 use a precipitation-chamber, the products of combustion can escape through an open-topped stack and the air or steam pipe can be led into the furnace at a point where the stack is contracted to produce the injector effect and 9° the consequent vacuum below.

I do not limit myself to the specific details of construction herein described and shown in the drawings, as I desire to avail myself of such modifications and equivalents as fall prop- 95 erly within the spirit of my invention as herein set forth and claimed.