US2058706A - Bell operating mechanism for blast furnace tops - Google Patents

Description

Oct. 27, 1936.; s. L. MARTIN 2,053,706

" BELL OPERATING MECHANISM FOR BLAST FURNACE TOPS Filed March 9, 1935 2 Sheets-Sheet 1 Isfiventor STEPHEA/LNART/N (lttornegs Oct-'27, 1936. s, MARTIN BELL OPERATING MECHANISM FOR BLAST FURNACE TOPS Filed March 9, 1935 2 Sheets-Sheet 2 I 42 I 40 Z0 .5 41 3nv entor 41 'STEPHf/V LMART/N attorhegs Patented Oct. 27, 1936 UNITED STATES PATENT OFFICE BELL OPERATING MECHANISM FOR, BLAST FURNACE TOPS This invention relates to bell operating mechanism for blast furnace tops and more particularly to a simple, safe and effective means for raising and lowering the large bell of a blast furnace top.

In modern blast furnaces the ore, coke, limestone, etc, is charged into the top of the furnace through two independently movable bells or valves which are adapted to close the top and bottom openings of the stationary charging hopper. In the operation of a blast furnace, when it is desired to charge material into the top thereof, the charge is deposited in the upper rotatable hopper and then the top or small bell is lowered permitting material to be dumped into the main stationary hopper. The bottom or large bell is closed during this operation and serves to support the material until the desired quantity has been charged into the main hopper. When the charge has been thus deposited in the main hopper the small bell is closed and the large bell is lowered permitting the charge to drop into the furnace. As soon as the charge is deposited in the furnace the large bell is closed and an effective seal is provided at the top of the furnace. With this arrangement, as is well understood by those skilled in the art, the material can be charged into the top of the furnace without permitting gas to escape or air to enter.

7 In the usual blast furnace top provided with the above described double bell arrangement the bells are connected to operating rods or tubes which extend upwardly and are secured to the ends of levers which are fulcrumed on the framework on the top of the furnace. These levers carry counter-weights at their outer ends which weights must be sufiicient to support both the bell structures and the weight of the material charged thereon. In the case of the bottom or large bell this total weight will be considerably greater than in the case of the small bell as the large bell must support the entire charge up until the time it is dropped into the furnace while the small bell need only support a part of the full charge of material at a time.

In the arrangement just described the heavy counter-weights, and particularlytheheavycounter-weight of the large bell, must be supported on the top of the furnace structure. This necessitates an extremely heavy, strong and expensive supporting framework on the top of the furnace. Another serious disadvantage of this arrangement is that in case of explosions, which sometimes occur in the main hopper between the bells, the large bell will be moved downwardly with great force and the counter-weight will move up and may crash into and break the supporting structure and wreck the furnace top. Also, in order to lower the large bell, its counter 5 Weight must be lifted. This must be effected through a cable passing over suitable sheaves to a winch on the ground. Inasmuch as the counter-weight and counter-weight lever arm must be disposed in a particular location on the top 10 of the furnace in order to avoid striking the various pipes and structural supporting members,

a complicated system of sheaves is frequently required in order to bring the operating cable down to the ground at a point where the bell 15 operating hoist may be conveniently located.

It is among the objects of my present invention to provide a bell operating mechanism for blast furnace tops by which the above noted defects are overcome. Other objects are: the provision 20 of a bell operating mechanism for blast furnaces which requires a smaller counter-weight to support the same load; the provision of a bell operating mechanism in which a bell hoist of relatively small capacity may be used thus saving in first cost and operating cost; the provision of blast furnace bell operating mechanism in which the counter-weight is located at the ground level thus eliminating the possibility of wrecking the furnace top due to explosions between bells; 30 the provision of a blast furnace top in which the movement of the bell and its supporting rod is always in an absolutely vertical direction thus insuring perfect seating of the bell; the provision of bell operating and supporting mech- 35 anism which may be readily adjusted to properly center the bell in relation to its seat.

The above and other objects of my invention will appear from the following description of a preferred embodiment thereof, reference being 40 had to the accompanying drawings in which Figure 1 is a fragmentary side elevation, partly in section, illustrating the top of a blast furnace with my improved bell operating mechanism installed. 45

Figure 2 is a fragmentary side elevation, partly in section, diagrammatically illustrating the ground end of the bell operating cable together with the counter-weight and operating motor.

Figure 3 is an enlarged side elevation, partly in section, showing the upper end of the bell supporting rod and my improved bell operating mechanism associated therewith.

Figure 4 is a view of the apparatus shown in 55 Figure 3, partly in section, and taken substantially on line 44 of Figure 3.

Figure 5 is an enlarged cross sectional view of my improved universal joint type bearing taken on line 55 of Figure 3.

In Figure l I have illustrated the top structure of a conventional type of blast furnace in which my improved bell operating mechanism has been installed to operate the lower or large bell.

The top of the furnace supports the stationary hopper 2, the bottom end of which is adapted to be closed by the large bell 3. A rotatable hopper 4 projects down into the top of the stationary hopper 2 and any suitable means (not shown) may be utilized for rotating the hopper 4 to distribute the material charged thereinto by the skip car 5 evenly into the stationary hopper 2. The skip car 5 is shown in its upper position in which the material is discharged into the rotatable hopper 4. This car 5 is adapted to run on and be guided by tracks 6 and be operated by the cable 1 which passes over a suitable sheave 8 to the ground. The bottom of the rotatable hopper 4 is normally closed by the small bell 9 which is supported by the tubular member ill. Protecting rings i may be disposed about the tubular member H) to protect it from the abrasive action of the material charged into the hopper 4. A coupling I2 is secured to the top of the tubular member I and rods l3 extend upwardly from the coupling |2 to links I4. These links M have pivotal connections at their lower ends to the rods I 3 and at their upper end to opposite sides of the short end of the small bell operating lever l5. The small bell counter-weight i6 is carried on the long end of the lever l and a cable ll passes upwardly over the sheaves i8 and Hi to a suitable winch (not shown) on the ground. The counter-weight E6 is heavy enough to normally maintain the small bell 9 in its upper or closed position and to support any load of material which may be deposited in the rotatable hopper 4. When it is desired to open the small bell 9 its winch mechanism will be operated to raise the counterweight IG and the long end of the lever l5 thus lowering the tubular support l0 and the bell 9.

The large bell 3 is supported by a rod 29 which extends upwardly through the tubular support ll) of the small bell 9. The upper end of the rod 20 is secured to my improved bell operating mechanism, the details of which will be best seen in Figures 3, 4 and 5.

A transverse connecting piece 2| is secured to the top end of the rod 28 and extending upwardly therefrom are the cross head arms 22 which are connected at their upper ends by the shaft 23 on which is rotatably mounted the roller 24. This roller 24 is adapted to move up and down in a guideway formed between the surfaces 25 and 26 of the downwardly extending brackets 2'! and 28 respectively which brackets are in turn suitably secured to the top frame structure of the blast furnace. The guideway 26 is grooved, as seen in Figure 3, the groove being just slightly wider than the face of the roller, in order to guide the roller and cross head 22 and prevent lateral movement thereof. The guideways 25 and 2'5 are spaced a distance slightly more than the diameter of the roller 24 so that in operation of the apparatus the roller will engage only one of these surfaces. Connecting rods 29 and 3B are pivotally mounted on the shaft 23 at their lower ends and on the crank shaft 3| which is carried by the sheave or pulley wheel 32, at their upper ends. The sheave 32 is preferably keyed to a shaft 33 which has a bearing in the brackets 34 and 35. These brackets 34 and 35 are mounted on the transverse beams 36 of the furnace top structure and are provided with lugs 31 which extend laterally outwardly adjacent their bases. These lugs cooperate with centering bolts 38 and the fixed adjusting box members 39 to provide means for positioning the brackets 34 and 35 so that the supporting rod 20 and the large bell 3 will be accurately centered in the hopper 2.

As is best seen in Figures 3 and 5 the connecting rods 29 and 30 are carried on the ends of the shaft 3| which is mounted on roller bearings 40, the outer races 4| of which are carried by the spherical member 42. This spherical member 42 is supported in a correspondingly shaped bushing 43 which may be held in a boss 44, formed on the web 45 of the sheave 32, by a bolt 46. This connection between the upper ends of the connecting rods 29 and 3E! and the sheave 32 permits of some sidewise movement of the connecting rods 29 and 30 and thus accommodates any small swaying or disalignment of the rod 20, the cross head members 22, the connecting rods 29 and 30 and the sheave 32.

The chain 41 extends around the sheave 32. The outer periphery of the sheave 32 is provided with lugs 48 and a pin 49 extends through the lugs 48 and one link of the chain 4! thus securing the chain 47 to the sheave 32 and positively connecting the sheave and chain so that there can be no slippage therebetween. A cable 50 is secured to the left hand end of the chain 41 (Figure 1) and a cable 5| is secured to the right hand end thereof. The cable 5| extends down to the ground level where it passes over a sheave 53 and supports a counter weight 63 disposed in a well or pit 62. The sheave 53 is freely rotatable on the shaft 56 which may be supported on a suitable bracket 54. The outer end 50 of the cable which extends around the sheave 32 also leads to the ground level where it is securel to any suitable type of bell hoist indicated at 60. This bell hoist consists essentially of a drum 59 about which the cable is wound and a driving motor 6! which drives the drum through suitable gearing. It will be seen that the counter weight 63 exerts a constant and uniform load on the cable 5| and that when the drum 59 of the bell hoist is rotated in clockwise direction the cable will be moved to rotate the sheave 32 in counter clockwise direction thus lifting the counter weight 63 and lowering the bell 3.

The operation of my improved bell operating mechanism which has been illustrated and described in connection with the large bell on a furnace top is as follows:

When the parts are in the position illustrated in the drawings the large bell 3 is in its raised or closed position. The counter weight 63 is heavy enough to exert a force on the cable 5| which, transmitted through the sheave 32 and the other connecting apparatus, will support the weight of the bell and any load which may be imposed thereon due to the charge of material in the hopper 2. Normally the bell 3 is held closed by the counter weight 63. When it is desired to lower the bell 3 to discharge the charge into the furnace top the bell hoist 60 will be rotated in counter clockwise direction. This rotation will lift the counterweight and will cause a corresponding counter clockwise rotation of the sheave 32. During this rotation of the sheave 32 the supporting shaft 3| will move downwardly as will the connecting rods 30 and the supporting rod 20.

The roller 24 will be guided during this downward movement by the guide faces 25 and 26. In the ordinary operation of the apparatus the counterclockwise rotation of the sheave 32 will continue until the boss 44 on the web 45 of the sheave '32 reaches its lower dotted position 44'. When this point is reached the bell 3 will have been lowered to its completely open position. After the charge has beendeposited in the furnace top. the bell 3 may be lifted and closed by reversing the direction of rotation of the bell hoist motor and causing the sheave 32 to, move in clockwise direction. Substantially no power will be required during this rotation of the motor as the counter weight 63 is heavy enough to lift all of the parts which are supported from the sheave 32.

It will be seen that when the bell 3 and the bell lifting mechanism parts are in the positions shown in the drawings the maximum lifting force is imposed bythe counter weight 63 on the cable 5| and the chain 41. The center of the shaft 33 may be considered, to be the fulcrum of a lever, one arm of which is equal to the diameter of the sheave (the distance from the center of the sheave 32 to the center line of the chain 41) and the other arm of the lever will be the perpendicular distance from the center of the shaft 33 to a line drawn from the center of the shaft 3! to the center of the shaft 23. It is seen that, in the position of Figure 3, this line drawn from the center of shaft 3| to the center of shaft 23 will be quite close to the center of the shaft 33, providing a comparatively short lever arm. Thus, the mechanical advantage will be in the ratio of this short lever arm to the above noted long lever arm. When the bell 3 is in its raised position and this relatively great mechanical advantage exists the greatest force will be effective to oppose downward movement of the bell 3. This is desirable in order to support the charge in the hopper 2 by means of the smallest possible counter weight 63.

As the sheave 32 is moved counterclockwise the center of the shaft 3! moves away from a vertical center line passing through the center of the shaft 33, and the short arm of the lever effective to lift the bell 3 will become longer until it reaches its maximum length when the center of the shaft 3! and the center of the shaft 33 both lie in a horizontal plane. Then, as the shaft 3| drops to the position 44, this lever arm again diminishes in length until at 44 it is substantially the same as it was in the full line position shown in Figure 3. Thus the greatest possible leverage will also be effective to assist the counterweight in starting to lift the bell 3 and its supporting parts from the lowest or wide open position.

From the above description it will be seen that the maximum lifting force is imposed on the bell 3 when it is in its upper or closed position and that this force will diminish as the bell opens and the charge thereon is deposited in the furnace. Furthermore, the maximum lifting force will also be available during the initial movement of the bell in upward or closing direction. By means of this arrangement the power necessary to operate the bell may be reduced and the size of the counter weight 63 kept at a minimum. In the usual type of bell counter weight arrangement the greatest hoist torque is required to start and acceleratethe dead weight of the bell and counter weight to normal speed. With my improved bell supporting and; hoisting apparatus these peak 5 starting torque loadswill, not be imposed upon the driving motor because during the starting motion of the bell, both at its closed and open positions, the maximum mechanical advantage is obtained and the minimum motion of the bell takes place for any given angular movement of the sheave 32.

Another advantage of the variable lever arm arrangement obtained by my sheave, connecting rod and cross head assembly is that the hoist motor 6i can be operated at constant speed and a variable speed movement of the bell will be obtained. Of particular advantage is the fact that as the bell is being lifted and approaches its closed or seated position the vertical movement thereof is at its slowest rate due to the fact that most of the movement of the pin 3i is horizontal at this point. This results in an easy closing of the bell and the shock and vibration incident to the closing of the bell with present types of equipment is eliminated. Still another advantage of my apparatus arises from the fact that a rigid non-collapsible connection is provided extending from the bell 3 up to the sheave 32. This results in a positive opening of the bell and overcomes the disadvantage, experienced in bell supporting mechanisms which include cables or links, of the bell sticking in closed position due to the gas pressure in the furnace when it is desired to open the bell with no burden on it. With non-rigid connections when this occurs the bell may drop suddenly with resulting strain and damage to the apparatus.

By disposing the counterweight 63 at the ground level all danger of wrecking the top of the furnace due to explosions between the bells is eliminated. Moreover, the: top supporting framework of the furnace may be very considerably lightened as it is unnecessary to support the large bell counter weight thereon. This results in a very considerable saving in first cost. The system of sheaves on the furnace top is also simplified by my improved bell operating mechanism as the sheave 32 and its supporting brackets 34 and 35 may be positioned so that the operating cables 53 and 55 extend directly to the bell hoist and counter weight guide sheave without passing over intermediate guiding sheaves. It will be understood, however, that, if desired or necessary for any reason, the counterweight can be supported on the furnace top or other aboveground location and a number of the adv-antages of my operating mechanism obtained.

Adjustment of the position of the bell is simplified as it is only necessary to turn the centering bolts 38 to move the brackets 34 and 35 into position to accurately center the bell at the bottom of the hopper 2. As the movement of the rod 23 is guided by the roller 24 of the cross head 22, the bell and its supporting rod 23 will move in an absolutely vertical direction, thus insuring perfect seating of the bell at the bottom of the hopper 2 and eliminating, insofar as possible, wear due to rubbing of the rod 23 within the tubular support H! of the small bell 9.

Although I have described the illustrated embodiment of my invention in considerable detail, it will be understood by those skilled in the art that modifications and variations may be made from the specific form herein shown and described without departing from the spirit of my invention. I do not, therefore, wish to be limited to the specific details shown in the attached drawings and described in the specification, but claim as my invention all embodiments thereof coming within the scope of the appended claims.

I claim:

1. Bell operating mechanism for blast furnace tops and the like including a vertically extending bell supporting member, a cross head secured to the upper end of said bell support, a vertically disposed guideway for said cross head, a sheave wheel rotatably supported on the furnace top, a connecting rod pivotally connected at one end to said cross head and at its opposite end to a shaft supported by said rotatable sheave Wheel, and means for rotating said sheave wheel whereby said bell will be moved vertically.

2. Bell operating mechanism for blast furnace tops including a vertically extending bell supporting rod, a cross head at the upper end of said rod, a sheave wheel mounted on the blast furnace top and carrying a shaft spaced from the center of said wheel, a connecting rod extending between said cross head and said shaft, and guides for said cross head whereby rotary movement of said wheel and shaft will be transformed into vertical movement of said cross head and bell supporting rod.

3. Bell operating mechanism for blast furnace tops including a vertically extending bell supporting rod, a cross head at the upper end of said rod, a sheave wheel mounted on the blast furnace top and carrying a shaft spaced from the center of said wheel, a connecting rod extending between said cross head and said shaft, guides for said cross head whereby rotary movement of said sheave wheel and shaft will be transformed into vertical movement of said cross head and bell supporting rod, a bell hoist, power means for rotating said bell hoist in either direction, a counter weight supported by a cable secured to and extending around said sheave wheel, and connecting means extending between said sheave wheel and said bell hoist whereby rotation of said bell hoist will cause corresponding rotation of said sheave wheel.

4. Bell operating mechanism for blast furnace tops including a vertically extending bell supporting rod, a cross head at the upper end of said rod, a sheave wheel mounted on the blast furnace top and carrying a shaft spaced from the center of said wheel, a connecting rod pivotally connected to and extending between said cross head and said shaft, said shaft and wheel being so disposed relative to said bell supporting rod that when said rod is in its top position and the bell is closed the distance between a straight line, drawn from the center of said shaft to the pivotal connection of the connecting rod and cross head, and the center of said sheave wheel will be at its minimum value.

5. Bell operating mechanism for blast furnace tops including a vertically extending bell supporting rod, a cross head at the upper end of said rod, a sheave wheel mounted on the blast furnace top and carrying a shaft spaced from the center of said wheel, a connecting rod pivotally connected to and extending between said cross head and said shaft, said shaft and wheel being so disposed relative to said bell supporting rod that when said rod is in its top position and the bell is closed the distance between a straight line, drawn from the center of said shaft to the pivotal connection of the connecting rod and cross head, and the center of said sheave wheel will be at its minimum value, and means, operable from the ground level, for rotating said sheave wheel.

6. Bell operating mechanism for blast furnace tops including a vertically extending bell supporting rod, a cross head at the upper end of said rod, a sheave wheel mounted on the blast furnace top and carrying a shaft spaced from the center of said wheel, a connecting rod pivotally connected to and extending between said cross head and said shaft, said shaft and wheel being so disposed relative to said bell supporting rod that when said rod is in its top position and the bell is closed the distance between a straight line, drawn from the center of said shaft to the pivotal connection of the connecting rod and cross head, and the center of said sheave wheel will be at its minimum value, and means for rotating said sheave wheel to lift and lower said bell supporting rod, said means including a bell hoist, operating connections between said furnace top sheave and said bell hoist, a counter weight supported by a cable from said sheave and adapted to exert a substantially constant force tending to rotate said sheave in a direction to lift said bell supporting rod, and means for rotating said bell hoist in either direction.

7. Bell operating mechanism for blast furnace tops and the like including a non-collapsible vertically extending bell supporting member, a cross head secured to the upper end of said bell support, a vertically disposed guideway for said cross head, a sheave wheel rotatably supported on the furnace top, a connecting rod pivotally connected at one end to said cross head and at its opposite end to a shaft supported by said rotatable sheave wheel, and means for rotating said sheave wheel whereby said bell will be moved vertically.

8. Bell operating mechanism of the type described including a vertically extending bell supporting member, a sheave wheel rotatably mounted above the upper end of said bell supporting member, straight line motion means connecting said sheave wheel and said bell supporting member whereby rotation of said sheave wheel will be transformed into vertical movement of said bell supporting member, and means for rotating said sheave wheel whereby said bell will be moved vertically.

9. Bell operating mechanism of the type described, including a vertically extending bell supporting member, a sheave wheel rotatably mounted above the upper end of said bell supporting member, straight line motion means connecting said sheave wheel and said bell supporting member whereby rotation of said sheave wheel will be transformed into vertical movement of said bell supporting member, and means for rotating said sheave wheel whereby said bell will be moved vertically, said means including a counter weight supported by a cable secured to said sheave wheel and adapted to exert a constant force on said sheave wheel tending to maintain said bell in closed position, a bell hoist, a cable extending between said sheave and said bell hoist, and power rcneans for rotating said bell hoist in either direcion.

10. Bell operating mechanism of the type described, including in combination an upwardly extending bell supporting member, a cross-head attached to said member, a crank, a connecting rod pivotally attached at one end to said crosshead and at the other end to said crank, and means for turning said crank, said crank being so disposed that a maximum lifting mechanical advantage is obtained during the final bell closing movement and the initial bell closing movement of said crank and connecting rod.

11. Bell operating mechanism of the type described including in combination an upwardly extending bell supporting member, a cross-head attached to said bell supporting member, a crank having one arm of fixed effective length and another arm of Variable effective length, a connecting member between said crank and cross-head, a counter-weight, and means for attaching said counter-weight to the fixed length arm of said crank whereby said counter-weight will act through said crank, connecting member and cross-head to lift the bell supporting member closed positions of the bell.

STEPHEN L. MARTIN.

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