US1812118A - Method of and apparatus for charging electric furnaces - Google Patents

Description

June 30, 1931. A. G. RIPBERGER 1,312,118

METHOD OF AND APPARATUS FOR CHARGING ELECTRIQFURNACES Filed Nov. 11, 1930 E SheBtS-Sheet 1 gwumatoz AGRlpbe/yer June 30, 1931 A. e. RIPBERGER METHOD OF AND APPARATUS FOR CHARGING ELECTRIC FURNACES Filed Nov. 11,1930 5 Sheets-Sheet 2 AGK/pbe/y June 30, 1931. A. G. RIPBERGER 1,812,118

METHOD OF AND APPARATUS FOR CHARGING ELECTRIC FURNACES Filed NOV. 11, 1950 3 Sheets-Sheet 3 gwoemtoc Afibobelyer 119-4 9 w/ Patented June 36; 1931 e raw materials utilized in melting a charge in arc-type electric melting furnaces are charged into the furnace shell through doors in the side of the same. This charging operation is essentially a hand operation and requires a considerable length use, as follows: of time for being carried out. Moreover, the charge of raw materials cannot be evenly placed on the furnace hearth, which increases v the length of time required for melting the charge. And finally, the current to the elec- ALEXAIIDER G. RIPBERGER, 0F PHILQ, OHIO Application filed. November 11; 1930. Serial No. 494,975.

trodes must be turned off during the charging relative movement.

operation thereby creating an operating loss in carrying out the charging operation.

The aggregate losses of time consumed in charging and melting raw materials in such arc-type electric furnaces constitute operating losses, which must be included in the cost of melting a heat in such an electric. furnace, and which increase the cost of producing the finished product.

Many designs have been suggested for use in order to reduce these operating losses by shortening the charging time. All of these 'devices are characterized by the fact that the electrodes are first moved upwardly in order to clear the upper edge of the furnace shell; the roof and furnace shell are then separated to break'the seal therebetween by relatively 40 moving the roof and furnace shell vertically,

and the furnace hearth is then exposed by relatively moving the roof and furnace shell ity equ'al to that of the furnace, including the horizontally. t of a complete charge of raw materials weig A grab bucket containing the charge of carried therein.

raw materials is then positioned over the exposed furnace hearth and the charge is dropped on the hearth, the roof and furnace shell are then moved relatively horizontally until the roof covers the furnace shell, the

It is therefore one of present invention to eliminateeither in part or in entirety all of the above disadvantages encountered in charging present designs of arc-type melting furnaces.

[TED srarss PATENT orr ca METHOD OF AND APPARATUS FOR CHARGING ELEGTBIC FURNACES tively vertically until a seal is created between the same, and the electrodes are then moved downward until they contact with the charge at which time the current is turned on and the melting operation commences.

In one furnace design, the relative vertical and horizontal movement between the roof and furnace shell is accomplished by one slanting movement in order to hasten the time when the charge of raw materials may be cc dropped upon the furnace hearth.

However, all of such devices have a number of disadvantages which substantially 035?- set any gain in time required for carrying out the charging operation resulting from their The Weight of the furnace shell, roof, and electrodes is of such magnitude that relative movement between the same can only slowly be accomplished, and a very large amount 7a of power must be expended to produce such The furnace shell brick work, in being fully uncovered to expose the hearth, experienres a very great heat loss so as to require the expenditure of additional power for reheating the brick work after the completion of the charging operation. v

The charge of raw materials in being dropped from a grab bucket is not evenly distributed on the furnace hearth in a manner necessary for the economic operation of an arc-type electric melting furnace.

The grab bucket must have a capacity equal to that of the furnace so that only one crane trip is required for charging the furnace in order that the furnace shell will be uncovered for only a minimum time.

The handling crane for the grab bucket is thus required to be of large capacity in order to handle a heavy grab bucket of capacthe objects of the roof and furnace shell are hen moved rela- It is a further object of the present invention to materially reduce the time loss and consequent operating lossencountered in carrying out the operation of charging an arctype electric furriace.

Likewise it is an object of the present invention to eliminate the necessity of fully charged into the furnace on the furnace hearth.

Moreover, it is an object of the present invention to provide a charging device for electric furnaces for carrying out all of the above objects which can be readily erected and operated in connection with existing furnaces substantially without interrupting the operation of such furnaces, which may require only minor accessory devices to be added to the furnace construction per se.

And finally, it is an object of the resent invention to provide an electric urnace charging device which may serve for selectively or alternately charging two furnaces having the same hearth diameter placed side by side, with the charging device located between the furnaces.

These and other objects may be obtained by providing an electric furnace construction, a charging device therefor, and a method of operating the same which requires for carrying out the charging operation a lifting of the electrodes, a lifting of the roof through a very limited distance vertically of the furnace shell, the introduction of a material car-' rier in a horizontal direction into the space created between the roof and furnace shell,

the dropping of the charge of raw material from the material carrier to the furnace hearth in an even and uniform manner, the withdrawal of the material carrier from the space betweenthe roof and furnace shell, the lowering of the roof, and the lowering of the electrodes. y

One form of carrier which may be introduced in a horizontal direction into the space created between an electric furnace roof and shell is illustrated in the accompanying draw!- ings and may be stated in general terms-as consisting of a vertical spindle, a lower plate member provided with a plurality of openings or'slots, an upper carrier member provided with a plurality of pockets adapted to register with the openings or slots in the lower plate member when the plate member is moved to one position, means for simultaneously horizontally moving the two members to position the same in a space created between the roof and shell of an electric furnace, means for relatively moving the two members to bring the pockets and slots or openings into registry, and the external horizontal cross sectional contour of the members substantially conforming with the external. horizontal cross sectional contour and dimensions of the furnace hearth.

One form of improved charging device for electric furnaces is shown in the accompanying drawings, in which Figure 1 is a plan view of a typical arc electric furnace equipped with the improved charging deviceshown in full lines in position to receive raw, material, and shown in dot-dash lines in osition to discharge raw material onto the fiirnace hearth;

Fig. 2 is a vertical section through the furnace shown in Fig. 1, showing the material carrier of the charging device in section in discharging position as on the line 2-2, Fig. 3, located in the space created between the furnace roof and shell;

Fig. 3 is a plan view of the charging device showing the same in discharging position; and

' Fig. 4 is an elevation of the charging devioe, certain parts being shown in section as on the line 4-4, Fig. 1. v

Similar numerals refer to similar parts throughout the drawings.

A material charging devipe is indicated, generally at A in the drawings used in connection with a typical are electric furnace indicated generally at B. The arc-ty electric furnace B includes a shell 5, roviri e d with a hearth 6, and a cover or roof The cover or roof 7 is provided with a plurality of openings '8, through which are slidably mounted the electrodes 9, carried on electrode supporting structure 10. Raising and lowering mechanism indicated generally at 11 is provided adjacent the furnace shell for raising and lowering the electrodes 9, vertically of the shell 5 and hearth 6 thereof.

The furnace B, including its shell, roof, electrodes, and electrode supporting mechanism is mounted for rocking movement on a pier or foundation 12. Suitable tilting or .rocking mechanism'13 is provided for tilting the furnace to discharge its molten contents from the pouring spout 14, when the pouring spout door 15 is raised by operating mechan1sm'16 and when the furnace B is in tilted position. a

' An opening 17 is provided in the side wall 5 of the usual arc-type electric furnace, and

the opening 17 is equipped with. a/ door 18,

through which raw materials to betnelted in the furnace are ordinarily introduced therein. For the purposes of the present invention,

the opening 17 and door 18 will only be uti- 'lized for inspecting or conditioning the charge being melted in the furnace, or for inspecting the furnace when the. same is not being 0 rated.

For t e purposes ofthe present invention, the [roof 7 of the furnace 13 maybe provided with a plurality of brackets 19 which are slidably mounted on posts or pillars 20. The roof 7 may likewise be provided with a plurality of projecting lugs 21, to which crane hooks 7 may be attached for raising and lowering the roof 7, vertically of the shell 5, slidably on the posts 20.

The material charging device A includes a base 22 which may be secured in any suitable manner, to a foundation. A. mast, post or spindle 23 is mounted on the base and extends vertically thereof for journalling the hub 24, of the lower plate member 25, and the hub 26, of the upper carrier member 27.

An arm 28, carrying a counterweight 29, projects laterally from the hub 24 to provide means for compensating for the weight of the lower plate member 25 which extends laterally of the hub 24-. in the opposite direction.

' A bevel gear is preferably formed integrally on the hub 24, and meshes with at bevel pinion 31, mounted on the shaft 32, journaled in bearings 33, provided with a gear 34, meshing with a pinion 35, mounted on the shaft 36, of the drive motor 37.

A spindle 33, provided with a bevel pinion 39, is jcurnaled at 40 and 40 on the upper carrier member 27, and the spindle 38 likewise is provided preferably with a chain sprocket 41, operatively connected by the link chain 42, to a sprocket on the shaft of the motor 43. The motor 43 is mounted on a bracket 44 ext tending outwardly from the upper carrier member 27. The bevel pinion 39 meshes with rack teeth 45, formed on the upper surface of the lower plate member 25.

The lower plate member 25 may be provided with a plurality of brackets 46, mounting rollers 47, which bear on a flange 48 projecting from the upper carrier member 27, for supporting some of the weight of the lower plate member from the upper carrier member which may be conveniently reinforced by ribs 49.

The upper carrier member 27 is'provided with an upper horizontal wall 50 and a plurality of vertical walls 51 forming pockets 52, 53, 54, 55 and 56 having an irregular but predetermined design, shape and capacity.

Likewise, the lower plate member 25 is provided with a plurality of openings or slots 57 53, 59, and 60 having a contour similar to the horizontal cross sectional contour of the pockets 52, 53, 54 and 55 respectively, and adapted to register respectively with the pockets 52, 53, 54 and 55 respectively, when the upper carrier member 27 and lower plate member 25 are in the material discharging position shown in Figs. 2 and 3 of the drawings.

/V hen the upper carrier member 27 and lower plate member 25 are in the raw material receiving position shown in Figs. 1 and 4 of the drawings the solid portions of the lower plate member 25 register with the lower ends of the pockets 52, 53, 54,55 and 56 to form the bottoms of the pockets so that raw material to be charged to the furnace B maybe selectively distributed in the desired quantities and location in the pockets.

The operation of the device is as follows:

During the time when a heat is being melted and poured from the furnace B, the charging device A is in the position shown in full lines in Fig. 1. The desired quantities of raw materials to be charged into the furnace B for the next heat are selectively deposited in any suitable manner in the pockets 52, 53, 54, 55 and 56 of the carrier member 27 by the operator. The height of the charge of raw materials deposited in the pockets is preferably somewhat less than the depth of the pockets.

After the heat has been poured from the spout 14 of the furnace B, and. the furnace B is returned to vertical position as shown in Fig. 2, the electrodes 9 are raised by the mechanism 11 to the position shown in Fig. 2. Crane hooks are then engaged with the lugs 21, and the roof 7 is raised a limited distance to the position shown in Fig. 2, to create a space C between the roof 7 and shell 5 of the furnace The motor 37 isthen started, which rotates the members 25 and 27 in a horizontal plane, about the mast 23 as an axis, to position the members 25 and 27 in the space C created between the roof 7 and shell 5 of the furnace B, until the position of the parts shown in dotdash lines in Fig. 1 is reached, when the motor 37 is stopped.

The motor 43 is then Operated, which through its chain and sprocket connection 4l42, rotates the bevel pinion 39 to swing the upper'carrier member 27 backward to the position shown in Figs. 2 and 3, so that the slots 57 58, 59 and 60 in the lower plate member 25, register, respectively, with the lower ends of the pockets 52, 53, 54 and 55, thereby permitting the charge of raw materials l) to drop from the pockets onto the i hearth 6 of the furnace as well shown in Fig. 2. By properly designing the pockets and slots, the shape of the charge after it comes to rest on the hearth can be predetermined with complete success.

The motor 37 is then started in a reverse direction to swing the upper and lower members 25 and 27 back to the position shown in. Fig. 1, after which the roof 7 and electrodes 9 are moved downward for operating the furnace B'to produce another heat.

The members 25 and 27 are then moved relative to one another to position the solid portions of the lower plate member 25 so as to form bottoms for the pockets 52, 53, 54, 55- and 56 of the upper carrier member 27.

Accordingly, only a very limited space is created between the roof and shell of the furnace in which the charging device is horizontally introduced so that the roof and electrodes are moved a minimum distance, and so that the heat loss from the furnace shell durng charging will be a minimum, resulting in decreasing3 he time required for charging the furnace together with decreasing the cost of carrying out the charging operation.

Moreover, by use of the improved device, the charge of raw materials is evenly, selectively and uniformly distributed on the furnace hearth so that the time and power required for heating the charge in the furnace is a minimum. 4

It is pointed out that the external shape and configuration of the carrier and plate members of the charging device A approximates the horizontal cross sectional contour of the furnace, so that two fufnacesof the same size located adjacent one another may be served by a single charging device A located between the furnaces and adapted to have its carrier member swung selectively or alternately horizontally into the space created between the roof and shell of each furnace.

And finally, the charging device may be utilized in connection with existing furnaces by the addition of only a few minor accessory devices.

a It is pointed out that the improved method of charging raw materials into an electric furnace may be carried out by introducing a raw material carrying conveyor into the s ace created between the roof and furnace s ell, or by introducing an open hearth. type furnace charging mechanism into the s ace created between the furnace roof and shell,

* in lace of the swinging carrier member described in detail above.

I claim:

-1. The method of charging raw materials into anelectric furnace which consists in creating a limited space between the roof and shell of the furnace, moving a charge of raw materials horizontally into the space, and then vertically dropping the charge onto the furnace hearth.

2. The method of charging raw materials into an electric furnace which consists in raising the electrodes, vertically raising the furnace roof a limited distance to create a limited space between the roof and shell of the furnace, moving a charge of raw materials ried bythe charging means onto the furnace v hearth.

5. Charging apparatus for electric furnaces including a spindle, a lower plate member provided with a plurality of openings journaled on the spindle, an upper carrier member journaled on the spindle rovided with a plurality of pockets ada te to register with the openings when the p ate member is moved to one position, means for simultaneously horizontally moving the two members about the axis of the spindle, and means for relatively moving the two members to bring the pockets and o nings into registry.

6. (iliarging apparatus for electric furnaces including a base, a lower plate member provided with a plurality of openings, an upper carrier member provided with a lurality of pockets adapted to register with t e openings when the plate member is moved to one position, means mountin the members on the base, means for sim taneously horizontally moving the members on the base, and means for relatively moving the two members to bring the pockets and openings into registry.

7. Charging ap aratus for electric furnaces includi a. spin e, a lower plate member provide with a lurality of openings journaled on the spin le, an upper carrier member journaled on the spindle rovided with a plurality of pockets adapte to register with the openings when the plate member is moved to one position, means for simultaneously horizontally movin the two members about the axis of the spin le, means mounted on the upper carrier member for relatively movin the two members to bring the pockets an openings into registry, and means for supporting a portion of the weight of the lower plate mem er on the upper carrier member. In testimony that I claim the above, I have hereunto subscribed my name.

G. RIPBERGER.

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