US2037997A - Mechanically operated smelting hearth - Google Patents

Description

April 2l, 1936. w. E. NEWNAM MECHANICALLY OPERATED SMELTING HEARTH Original Filed June 4, 1928 2 Sheets-Sheet l April 21, 1936, w. E. NEWNAM MEGHANICALLY OPERATED SMELTING HEARTH original Filed 1928 2 Sheets-Sheet 2 June Patented Apr. 21, 1936 UNITED STATES MECHANICALLY `OPERATED SMELTING HEARTH William` E. Newnam, Collinsville, Ill., assignor to National Lead Company, St. Louis, Mo., a corporation of New Jersey Application June 4, 1928, Serial No. 282,663 Renewed December 13, 1934 7 Claims.

This invention relates to smelting hearths, and more particularly to the type described in Patent No. 1,388,144, granted August 16, 1921.

.An ore hearth, designed more particularly for the smelting of lead, comprises a comparatively deep basin of cast iron, a water back having tuyres at the lower end thereof positioned just above the basin, an apron which extends forwardly from the basin, and a hood which extends 10 over the hearth. In the operation of such a hearth, the basin is filled nearly full of lead,

which is brought to a molten condition, and the ore and fuel are then placed so as to oat on top of this bed of molten metal in the basin and banked up against the Water back. If a blast is now applied to the tuyres, a part of the ore is reduced to a molten state and settles in the basin while the unmolten clinker rises to the top. In

the continuous operation, a charge of ore and fuel banked against the water back is rabbled soas to turn over and Work up the material on the hearth and bring the grey clinker to the surface;

this rabbling proceeds from one end to the other of the hearth and is succeeded by a backing oper- 5 ation to push back the rabbled charge against the Water back. The clinker is picked oft' and removed from the hearth for subsequent reduction in a blast furnace. Small quantities of ore and fuel in a ground condition, and preferably mixed, are scattered over the hearth after the charge has been backed. The molten metal is drawn off to form pig lead, while the fumes given off during the smelting operation pass upwardly and are caught by the hood, from whence they pass to the bag house, where they are collected,

, sintered and subsequently smelted.

The length of a hearth of the character described is limited from a metallurgical standpoint; for a continuous structure is not suiiicient-` ly elastic to permit accurate'control of the temperature, exhaust, rabbling, backing and addition of fuel. As a practical proposition, therefore, a hearth about eight feet in length is found to sea hearth, the ore is'spread at intervals of about two minutes; for the blast should be kept as low as possible, for the reason that a high blast has a tendency to increase the temperature to a point Where volatilization affects the extraction on the hearth by increasing the proportion that passes v into fume, which must be sintered and again smelted. Moreover, the exhaust or suction should vnot be any more than necessary to keep the Working atmosphere free from fuel and dust; for

cure vthe best,results. In the operation of such if there is excessive suction, the proportion carried off as fumes is again increased.

As a result, therefore, in the operation of a hearth of this character, there is a number of factors entering into the successful operation which determine the extraction. An important factor is the addition'of the material in the form of ground ore and coke breeze. Not only is it desirable that this material be fed in small quan@ tities, in order to spread a thin layer over thev mal0 terial already on the hearth and floating on the metal, but it is desirable that this material be spread uniformly throughout the length and width of the material bed. It is, moreover, de-

sirable that this feed of. the material follow the l5- rabbling and banking operations just as quickly as possible, in order that there .will always be a charge of fresh material dn top of the bed.

One of the objects of this invention, therefore, i is to provide a smelting hearth of the character 20 referred to with means whereby the material may be spread thereover uniformly in order to secure the desired result.

Another object is to provide means whereby this material mxay be spread over the hearth me- 25 chanically and in measured quantities at regular intervals.

Another object is to provide a hearth of the character described, having means for spreading the material over the hearth, 4which is simple in 30 construction, effective in its action, and economical to manufacture.

Further objects will appear from the detail description, 'taken in connectionwith the accompanying drawings, in which 35 Figure 1 is a front elevation of a hearth embodying this invention; and l Figure 2 is an end view.

In accordance with one embodiment of this invention, a carriage is mounted for movement 40 along the hearth, and on this carriage and movable therewith is a device adapted to spread the material vover the hearth. This device, in the embodiment described and shown, comprises a tray `mounted on the carriagefor movement to- 45 wards and from the hearth. A feeding device is arranged to feed measured quantities of the material to the tray when retracted, and after the receipt of each charge the tray is moved towards the hearth to spread the material there- 50 over; the tray moving back and forth as the carriage moves along the hearth from end to end. Upon retracting vthe tray to receive its receipt of the charge it is released and there- 55 70 the spring 42, and the latch 43 will take beafter arrested rather suddenly to project the charge therein over the hearth.

Referring now to the accompanying drawings, designates a hearth of the character referred to, which has a basin 2, an apron 3, a water back 4 provided with tuyres 5, and a hood I3. This hearth may be of any suitable or usual construction well known to those skilled in. the art, such as, for instance, that shown in Patent No. 1,388,144.

Mounted in front of the hearth are pairs of braced standards 20, which carry rails 2|.. A carriage 22 has wheels 23 rolling on the rails and fixed to shafts 24. A motor 25 mounted on the carriage is provided with a gear 26 meshing with a gear 21 loose on one of the shafts 24, while another gear 28 on the motor shaft meshes through an idler 28 with a gear 30 also loose on that shaft. A suitable clutch 3| may be provided to connect either the gear 21 or the gear 30'With the shaft so as to drive the carriage in one or the other direction. This clutch may be operated by a clutch shifter 32. It will be understood that the motor 25 may operate its shaft and the gears 26 and 28 through suitable reduction gearing as is usual Where a high speed motor is employed.V The clutch shifter may also have an arm 33, so as to be struck by suitable stops 34 on one of the rails 2|, in. order to automatically reverse the motor when the carriage arrives at one or the other end of the hearth.

Mounted on the carriage 22 is a lever 35 pivoted at 36 and having at its lower end a tray 31 for receiving the material. The upper end of the lever is connected by a cable 38 with a lever 39 pivoted at 40 and in the path of a series of pins 4l on one of the rails. The lever 35 is acted upon by a spring 42, which tends to move the lever and tray from full to dotted position. This lever is retained under spring tension and with the tray retracted by a latch 43 pivoted at 44 and connected bya lever 45 plvoted at 46 with a lever 41 pivoted at 40 and in the path of a series of pins 48 on and along the rail 2|.

Arranged on the carriage 22 is a material hopper 49, having a contracted bottom normally closed by a slide 50 having an opening 5I arranged to aline alternately with the bottom of the hopper and an aperture 52 in an adjustable bottom 53 below the slide 50. This slide is connected by a pitman 530 with a crank disc` 54 on a shaft 55 mounted on the carriage and having fixed thereto a sprocket 56 connected by a chain 51 with a sprocket 53 on a shaft 59 also mounted on the carriage 22. The shaft 58 has a bevel gear 60 meshing with a bevel gear 6| on a shaft 62 mounted in a bearing bracket 63 on the carriage 22. Loosely mounted on the shaft 62 is a pinion 63 meshing with a rack 64 on the rail 2l. Splined on the shaft is a clutch member 65 held against a clutch face attached to the pinion 63 by a spring 66.

It will be ncted that the clutch faces are beveled so that the clutch will slip in one direction and engage in the other direction.

' When the motor 25 is started, the carriage 22 will -be moved" along the hearth. During this movement, the engagement of the pins 4| with the lever 39 will move the lever 35 to aline the.

tray 31 with the opening 52; this will tension hind the lever and hold it in position. Thereafter a pin 48 will engage with the lever 41 so as to retract the latch 43 and permit the tray to move towards the hearth under the tension will reach the opening 52 at the time the tray alines therewith. Accordingly. when the tray is released, the charge of material deposited therein will be spread over the hearth. When positioning the bottom 53 having the aperture 52 therein, the pocket 5| can be arranged to aline more or less with this opening so as to vary the quantity of the charge deposited in the tray. This adjustment of the bottom 53 can be obtained in any suitable manner, as by mounting it slidably and securing it in adjusted position by set screws 63.

It will thus be seen that, as the carriage moves along the hearth, the tray will be actuated cooperatively with the movement of the carriage to periodically spread measured charges of the material over the hearth. The sudden arrest -of the tray facilitates the spreading of a thin layer of the material, and by the, proportioning of the quantity in each charge, the thickness of the layer may be made to suit requirements. When the carriage arrives at the end of the hearth, it may be manually stopped by movement of the shifter 33, or automatically by the engagement of this shifter with the pin 34 at that end. The movement of the carriage can then be reversed so as to cause it to take up its position at the initial end of the hearth. In order to secure a quick return, the gearing 28, 29 and 38 is used for securing this return movement. The gearing is, moreover, so proportioned that, during this return movement, the clutch 65 will slip so that no material will be fed to the tray during the return movement of the charge. 'I'his is preferable because it is desirable that the material be spread while the carriage is traveling in one direction along the hearth, in order that each t charge portion may receive its treatment before having superimposed on it another charge,

'While this invention has particular relation to means for spreading a charge of material uniformly over the hearth, it is to be understood that this spreading means may be used in cooperation with a rabbling device of the character disclosed in Patent No. 1,388,144, and even with a backing device, as well, of the character disclosed in application Serial No. 282,664, led June 4, 1928. It will further be understood that, while this invention is particularly applicable to the general character of hearth shown and described, it is applicable as to some of its features to other forms and types. It will, furthermore, be understood that certain features and sub-combinations are of utility and may be employed without referenceV to other features and sub-combinations; that is contemplated by and is withinthe scope of the appended claims. It is furthermore obvious that various changes may be made in details of construction, within the scope of the appended claims, without departing from the spirit of this invention. It is, therefore, to be understood that this invention is not to be limited to the specific details shown and/or described.

Having thus described the claimed is:

inyention, what is A aosaoev of the carriage through a predetermined distance` 1. A smelting furnace comprising, a hearth adapted to receive molten metal upon which floats the material to be smelted, a carriage -mounted for movement along said hearth, a material tray mounted on said can'iage for movement towards and from the hearth, means forD retracting said tray under tension, and means for releasing the tensioned tray.

2; A smelting furnace comprising, a hearth adapted to receive molten metal upon which floats the material to be smelted, a carriage mounted for movement along said hearth, a material tray mounted on said carriage for movement towards and from the hearth, means for retracting said tray under tension, means for releasing the tensioned tray, and means for arresting the released tray.

3. A smelting furnace comprising, a hearth adapted to receive molten metal upon which oats the material to be smelted, a trackway extending alongv the hearth, a carriage mounted on said trackway for movement back and forth in front ofthe hearth, means on said carriage for charging portions of material onto the hearth, means for driving said carriage, and means controlled by movement of the carriage for -automatically actuating said charging means at successive intervals during the movement 'of the carriage in front of the hearth. I

4. A smelting furnacel comprising. a hearth adapted to receive molten metal upon which floats the material to be smelted, a trackway extendingalongthe hearth, a carriage mounted 1 on said trackway for movement back and forth in front of the hearth, means on said carriage for charging portions of material onto the hearth, means for driving said carriage, and means automatically actuated in response to operation of the carriage driving means for successively actu-f ating the charging means upon each movement in one direction. I

5.,A smelting furnace comprising, a hearth adapted to receive. molten metal upon which iioatsthe material to be smelted, a trackway extending along the hearth, a carriage mounted on said trackway for movement back and forth in front of the hearth, means on said carriage for measuring successive equal portions of material, a charging device, and automatic means automatically actuated by movement of the carriage for a predetermined distance to transfer` material from said measuring means to said charging means' and to actuate the charging means.

6. A smelting furnaceV comprising, a hearth adapted to receive molten metal upon which floats the material to be smelted,` a trackway extending4 along the hearth, a carriage mounted on said trackway for movement back and forth in front of the hearth, means on said carriage for charging portions of material onto the hearth. means for driving said carriage, and means-for actuating said charging means successively as the carriage moves along the track, said actuating means being controlled by and actuated upon relative movement between the carriage and the track.

7. A smelting furnace comprising, a hearth adapted to receive molten metal upon which floats the material to be smelted, a trackway extending along the hearth, a carriage mounted on said trackway for movement back and forth in front of the hearth, a material container on said carriage, a charging device on the carriage, and means controlled by movement of the carriage along the track for automatically releasing material from said container into said charging device.

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