US1883413A - Puddling furnace - Google Patents

Description

00L 1932' H. w. SCHOENFELDT 1,883,413

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Oct. 18, 1932. I H. w. SCHOENFELDT 1,833,413

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Patented Oct. '18, 1932 UNITED STATES PATENT OFFICE i HENRY w. soironnr'nnnnor younos'rown, onro', ASSIGNOR or SIXTY AND EIGHT- 'rnn'rns run CENT roenoaen J. BURNS, or ermnnomo runnLrNs summon Application filed January 3.192s. Serial No. 244,253.

This invention relates to the metallurgy of iron and has special reference to a puddling furnace.

It is well known that wrought iron has been largely replaced by mild steel. It is alsowell known that there are many uses for material of this description in which wrought iron possesses highly superior qualities to any steel. For instance, where the metal is exposed to the corrosive influence of gases, as in smoke stacks and the like, wrought iron plates will show practically; no wear while mild steel plates will corrode and wear in extremely short time andrequire to be replaced. The principal reason why mild steel is used in many cases is simply because of its lower cost and the facility with which it can be produced by mechanical methods.

I-Ieretofore the production of wrought iron has necessitated a large amount of hand work. Attempts have been inadeto eliminate some'of the hand work by two means. In

some cases the puddling furnace itself has been made to revolve with a view of producing a mechanical puddling or separation of the slag and impurities from the bath' of molten pig iron so that the carbon is eliminated and pure iron left. In other cases a like effort has been made by operating on the bath with mechanically moved stirrers or rabbles but by none of these means has an effective separation of the dross and carbon from the bath been accomplished. A i

' One important object of the invention is to provide an improved form offurnace wherein the furnace itself is moved, either byrotation constantly in one direction or rotation first in one. direction and then the other and this is combined with the mechanical moving of a rabble so that the bath is not only stirred up bythe-movement of the furnace but this stirring effectually brings all parts of the bath into the range of operationof the rabble so that the entire bath is. properly and effectually worked to segregate the dross from the pure iron and a fresh surface of the bath "is constantly being exposed to the flame which is used to burn out the carbon existing in the pig iron as it is placed inthe furnace. Asecond important object of the invention the furnace and many other factors.

is to provide a novel arrangement of furnace wherein the furnace and the rabbleare coupled together by suitable mechanismso that movement of the furnace effects movement of the rabble, the latter being arranged .for disconnection and rest when desired by the operator.

Again, in the production of puddled iron it has heretofore been necessary to employ the services of a puddler having highly trained eyes to observe the conditions within the, furnace and therebydetermine the character of the iron and the change taken place in the reduction of the pig iron to Wrought iron so that the mass of wrought iron may be, removed at the proper time. Obviously, the human factor enters so largely into an operation of thischara'cter that no uniformity in the production can be assured. Different puddlers observing the conditions at the same instant .will judge differently as to these conditions and even the same puddler .will have his judgment affected by varying conditions in his health, the light outside of y reason of this even whereefforts have been made to produce wrought iron by mechanical puddling the eye of the operator has been depended upon to insure the results and consequently there is no uniformity in the iron' thus produced. A third and invention is to provide an improved form of puddling furnace wherein the. temperature and flame conditions within the furnace will be automatically controlled by thermostatic means so that the temperature and flame conditions. will be maintained at the desired points within very close limits.

' With the above and otherobjects in viewas will be hereinafter apparent, the invention consists in general of certain novel deta1ls of construction and comblnations of parts hereinafter. fully described, illustrated in the accompanying drawings and specifi cally claimed.

In the accompanying drawings like charactors of reference indicate like parts in the several views, and:

Figure 1 is a side elevation of a furnace very important'object of the constructed in accordance with this invention and showing one form of operating mechanism for the rabble.

Figure 2 is a horizontal median section through such a furnace.

Figure 3 is an end view of the furnace with the fuel supply and thermostatic control removed.

Figure 4 is a section on the line 4-4 of of supporting the'furnace for rotation.

Figure 5 is a section on the line 55 of Figure 1 but showing only the drive for the furnace.

Figure 6 is an enlarged detail section on the line 66 of Figure 2 illustrating the upper part of the rabble support.

Figure 7 is a detail section on the line 77 V of Figure 2 showing only the rabble used in 20 that figure and its support and connection.

' V Figure 8 is a detail section similar to Figure 2 but showing a second form of oper ating means for the rabble.

Figure 9 is a view similar to Figure 7 but showing the rabble used with Figure 8.

Figure 10 is a vertical section through the furnace and showing a pre-hearth and stack arrangement for such a furnace as isshown in Figure l. i 7 f 7 Figurell is a detail showing one manner of supplying a pulverized coal fuel to the furnace. V I Figure 12 is atypical wiring diagram for the reversing of a fuel or gas controlling motor such as is illustrated in Figure 2.

In each form of the invention herein shown the furnace is illustrated as consisting of a cylindrical casing 1Q having end walls 11 open at the center. This casing is lined in theusual manner with a suitable heat resisting lining 12 such as may be made from fire bI'lCkS, fire clay or any other material found best adapted for the purpose, the lining extending through the openings at the ends of thefurnace to cover the reinforcing rings 13 which are provided at these openings as clearly seen in the drawings. Spaced from each end of the furnace is a bearing ring 14 which surrounds the furnace and supports the wall thereof and these rings are also used for supporting thefurnace for rotation. To this end standards 15 are provided on each side ofthe furnace and in thesestandards are mounted flanged rollers '16 which engage the bearing rings 14 and thus carry the furnace. -Obviously while but two rings and corresponding standards have been here shown as "many'more' may be used as are found'desirable to support the furnace properly. Surrounding the furnace is also a gear ring 17 wherewith meshes a gear 18 mounted on a shaft'19 suitably supported by one or more bearings 20 and driven by a motor 21. By this means the furnace is given rotative 7 movement and it is to beunderstood at this Figure 1, the section showing only the method at one side of the furnace and in these standtime that by the use of the word rotative it is not desired to confine the movement necessarily to rotation continuously in one direction as by properly reversing the motor 21 from time to time or by a change in the driving arrangements a rotation first in one and then in the other direction may be accomplished. The word rotative, accordingly, as used in connection with this movement is to be understood to include both rotation continuously in one direction and rotation in one direction and then in the other.

In the form of the invention shown in Figures 1, 2 and 3 standards 22 are provided ards is supported a shaft'23 which carries on one end a gear 24 which meshes with the gear ring 17. This shaft is made in two sections whichniay be coupled or uncoupled by a suitable clutch 25 operated by a shipper lever 26. In the end of the shaft opposite the gear 24 there is provided some suitable form of crank mechanism here indicated by the eccentric 26 which is surrounded by a strap 27 carrying an eccentric rod 28 which passes through a cross head or guide 29' pivotally supported on the upper end of a standard 30. The end of this eccentric rod is forked as at 31 and receives the outer'end of'a rabble 32 which is connected to the eccentric rod by a remov- C5 able pin 33 so that the rabble can be readily connected to and disconnected from the operating mechanism. This rabble extends into the furnace through the opening 34 in the end wall and dips down into the bath, the loo rabble beingof some such form-as is inclicated in Figure 7 although not necessarily ofthis specific form. Just outside of the opening the rabble rests on a support 35 and is held in position to oscillate on that support "by pins 36 or other suitable means.

Similarly in the form shown in Figures 8 and 9 there are provided the standards 22, shaft 23, gear 24 and clutch 25. However, in this form the eccentric 26 is replaced by a bevel gear 37 which meshes with a bevel gear 38 carried ona shaft 39 supported in bearings 40 and running across the end of the furnace. On this shaft 39 there is an eccentric 41 surrounded by a strap 42 carrying an arm 43 which slides through a cross head or guide 44 pivoted on a standard 45. On the end of this arm'is a socket 46 in which is seated the "end of a rabble 47, the rabble being detachment of the furnace itself is accompanied by oscillatory movement of the rabble so that as the bath is moved around by the rotation of the furnace all parts are exposed to the action of the rabble it being remembered that p the molten iron is quite viscous after being worked a short time so that it is carried to some extent around with the furnace as the latter rotates and thus produce a flow of the mass which effectually keeps it in such motion that first one part and then the other is brought uppermost.

In order to supply the necessary heat a variety of means may be employed. As typical of one such means there is shown in Figure 2 a gas supply nozzle 49, the flow of gas being controlled by a valve 50. Now, it is well recognized that in the puddling of iron the heat must be kept under proper control and in the present instance arrangement is made whereby such control, and consequently the control of the flame for either oxidizing or reducing may be regulated. To this end thermostatic means such as are typically shown at 51 may be employed, these means operating by any well known manner an electric switch carried in a casing such as is shown at 52, the switch being diagrammatically indicated at 53 where it is shown as a reversing switch. This switch controls the flow of current to a controlling motor 54. which operates the valve 50 by a worm gearing 55. Thus when the heat tends to rise the operation is such that the valve 50 is closed or moved toward closed position while a lowering of the heat in the furnace reverses the motor 5i and the valve starts to open. It is to be understood that the control mechanism here shown is merely diagrammatic and is to represent any of the well known forms of thermostatic motor control which are adapted for high temperature use, it not being deemed desirable at this time to further illustrate or describe a specific type of such control. It is also to be understood that the controlling of the gas by the valve 50 is merely typical of a suitable control for the supply of gas, oil, or other fuel either by itself or mixed with air and it is not the intent in the present specification to set forth any specific control of this character.

Obviously the furnace may be supplied with burning gases to combine with the carbon in the bath by other means. For instance, in Figure 10 there is disclosed a prehearth or combustion furnace 56, the rabble i 32 working through the wall thereof. In

Figure 11 means is shown for providing pulverized fuel such as powdered coal and in this figure a hopper 57 feeds through a nozzle 58 into the intake of a blower 59 which is actuated by a motor 60 and blows air and the powdered fuel through 'a pipe 61 into the nozzle 62. Obviously the speed of the motor may be controlled in the usual manner for regulating the supply of fuel and air. In order to provide means for carrying off the productsof combustion the opening 63 op posite that through which the fuel enters is preferably connected-to a stack 64 having an elbow 65 jointed by a swinging joint 66 to the body of the stack so that the stack can be swung away from the opening 63 for the purpose of charging the furnace and withdrawing the iron afterthe puddling operation has ceased. It will be observed that by the control of the heat a charge may be placed in the furnace and the treatment carried on for a definite time at the definite temperature determinedto be most suitable, and by properly regulating the chemical nature of the charge and operating the furnace for uniform times under uniform heat'and flame conditions the product will be entirely uniform and this without depending in any way on the eye or other skill of the operator attending the furnace. Moreover, by proper regulation of the charge, time of treatment and conditions of heat and flame the iron may be-entirely separated from the carbon so that when the mass is removed and subject to the usual operations for the elimination of slag the resultant iron willbe wrought iron of a high grade of commercial purity.

There has thus been provided a simple and eflicient device of the kind described and for the purpose specified.

It is obvious that minor changes may be made in the form and construction of the invention without departing from the mastantially horizontal, means for supporting the furnace for rotative movement on said axis, a rabble extendlng 1nto said furnace and movable relative thereto, supporting means for said rabble, and means for simultaneously causing rotative movement of the furnace and oscillatory movement of the rabble.

2. In combination, a cylindrical puddling furnace having the axis of the cylinder substantially horizontal, means for supporting the furnace for rotative movement on said axis, a rabble extending into said furnace and movable relative thereto, supporting means for said rabble, means to cause rotative movement of the furnace, and an operating mechanism connecting the furnace and rabble to effect oscillatory movement of the latter upon movement of the furnace.

3. In combination, a cylindrical puddling furnace having the axis of the cylinder substantially horizontal, means for supporting the furnace for rotative movement on said axis, a rabble extending into said furnace and movable relative thereto, supporting means for said rabble, means to cause rotative movement of the furnace, and an operating mechanism connecting the furnace and rabble to effect movement of the latter upon movement of the furnace, said operating mechanism including a clutch whereby the rabble may be connected for operation and disconnected for rest during movement of the furnace.

4. In combination, a cylindrical puddling furnace having the axis of the cylinder substantially horizontal, means for supporting the furnace for rotative movement on said axis, a rabble extending into said furnace and movable relative thereto, supporting means for said rabble, means to cause rotative movement of the furnace, and an oper-

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